ippw-13 program abstracts - missions...

IPPW-13 Missions Session Monday, June 13, 2016– 12:30 PM to 5:30 PM

Conveners: Swati Mohan Kim Reh Brandon Smith STATUS OF INSIGHT ENTRY, DESCENT, AND LANDING FOR 2018 LAUNCH OPPORTUNITY

Missions Brooke Harper [email protected] 1

EXOMARS 2016 MISSION ANALYSIS: COASTING, ENTRY, DESCENT AND LANDING

Missions Davide Bonetti [email protected] 2

EXOMARS SCHIAPARELLI ENTRY, DESCENT AND LANDING SYSTEM DESIGN, DEVELOPMENT AND POST-LAUNCH STATUS

Missions Olivier Bayle [email protected] 3

Mars 2020 Entry, Descent, and Landing Overview Missions Allen Chen [email protected] 4

HOW DOES TERRAIN RELATIVE NAVIGATION CHANGE THE MARS 2020 ENTRY, DESCENT, AND LANDING?

Missions David Way [email protected] 5

TRN Performance in M2020 Missions Swati Mohan [email protected] 6

ESA’s Phobos Sample Return Mission Missions Thomas VOIRIN [email protected] 7

THE PSYCHE MISSION: EXPLORING A METAL WORLD FOR THE FIRST TIME

Missions David J. Lawrence [email protected] 8

Overview of the Asteroid Redirect Mission (ARM) Missions Daniel D. Mazanek [email protected] 9

ROSETTA STAR TRACKERS IN THE COMET DUST : UNDERSTANDING AND IMPROVING THE FLIGHT BEHAVIOUR THROUGH ON-GROUND TESTING OF THE STR EQM WITH THE MICROSTOS

Missions Pascal Regnier [email protected] 10

Earth Entry Vehicle Design for Comet Surface Sample Return

Missions Todd White [email protected] 11

Saturn PRobe Interior and aTmosphere Explorer (SPRITE)

Missions Amy A. Simon [email protected] 12

THE BEE: A BIOSIGNATURE EXPLORER TO SAMPLE PLUMES OF OCEAN WORLDS.

Missions Paul Mahaffy [email protected] 13

A DESCENT PROBE FOR EUROPA AND THE OTHER GALILEAN MOONS OF JUPITER

Missions Peter Wurz [email protected] 14

ESA’s CLEO/P study: 3 potential contributions to NASA’s Multi-flyby Europa mission

Missions Thomas VOIRIN [email protected] 15

Global Aerial Exploration of our Sister World with the Venus Atmospheric Maneuverable Platform (VAMP): Mission Science Objectives and Potential Instr

Missions Kevin H. Baines [email protected] 16

DAVINCI: Deep Atmosphere Venus Investigation of Noble Gases, Chemistry, and Imaging

Missions Lori S. Glaze [email protected] 17

THE DAVINCI AND OTHER PROBE DESCENT MODULE AND ENGINEERING DEVELOPMENT UNITS

Missions Michael Amato [email protected] 18

IPPW-13 Program Abstracts - Missions Session

July 13-17, Laurel MD USA. http://ippw2016.jhuapl.edu/ 1

STATUS OF INSIGHT ENTRY, DESCENT, AND LANDING FOR 2018 LAUNCH OPPORTUNITY. B. P. Harper1, E. D. Skulsky1, M. R. Grover1, C. E. Szalai1, D. M. Kipp1, J. A. Wertz1, E. P. Bonfiglio1, R. W. Maddock2, 1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 2 NASA Langley Research Center, Hampton, VA.

Introduction: Interior exploration using Seismic

Investigations, Geodesy, and Heat Transport (InSight) is a NASA Discovery Program mission that will send a robotic lander to the Martian surface. It offers the op-portunity to understand the formation and evolution of terrestrial planets through two years of analyzing the deep interior structure and processes of Mars.

Much of its design and enabling technologies are derived from NASA's successful Mars Phoenix lander mission from 2008, including the entry, descent, and landing (EDL) system architecture.

The spacecraft had been on track to launch in March 2016 until a persistent vacuum leak in its prime science instrument prompted NASA to suspend prepa-rations for launch. Fortunately, a proposed plan to re-design the science instrument was accepted in support of a 2018 launch.

As the 2018 mission profile emerges, new entry conditions and environments need to be characterized in order to assess EDL performance. A brief overview of the InSight EDL system design and development challenges will be higlighted. A closer look at the sig-nificant changes between the 2016 and 2018 oppor-tunites and the effects they have on EDL performance metrics and margins will be presented. Results from initial flight dynamics simulations indicate an increase in margin for several critical metrics, most notably peak heat rate. In fact, because of the improvements, trade studies on entry flight path angle may be revisit-ed to balance margin across the entire EDL phase. Cur-rent status and plans forward to facilitate the 2018 launch opportunity will be discussed.



EXOMARS 2016 MISSION ANALYSIS: COASTING, ENTRY, DESCENT AND LANDING

D. Bonetti1 ([email protected]), G. De Zaiacomo

1, G. Blanco Arnao

1, J.L. Cano González

1,

C. Parigini1, I. Pontijas Fuentes

1, A.Pagano

1

S. Portigliotti2 ([email protected]), L. Lorenzoni

3 ([email protected])

1 DEIMOS Space S.L.U., Ronda de Poniente 19, Tres Cantos, 28760, Spain

2 Thales Alenia Space Italia, Italy,

3 European Space Agency (ESA), The Netherlands,

The ExoMars programme is pursued as part of a

broad cooperation between ESA and Roscosmos. This

cooperation foresees two missions within the ExoMars

programme for the 2016 and 2018 launch opportunities

to Mars.

The ExoMars 2016 mission, reaching Mars on Oc-

tober, 19th

2016, is led by ESA and has been success-

fully launched from Baikonur by the Russian launcher

Proton-M on March, 14th

2016. The mission is current-

ly on its route to Mars in its assembly configuration

including the Trace Gas Orbiter (TGO) and the Entry,

Descent, and Landing Demonstrator (EDM, named

Schiaparelli), both supplied by ESA. The TGO scien-

tific mission aims at investigating atmospheric trace

gases: it is expected to begin in December 2017 fol-

lowing an aerobraking phase, and to run for five years.

On October 16th

2016, after 7 months of interplanetary

flight and 3 days before landing on the Mars surface

(Meridiani Planum), Schiaparelli will separate from the

TGO and with its mission it will provide Europe with a

demonstration of the technology for entry, descent and

landing (EDL) on the surface of Mars with a controlled

landing orientation and touchdown velocity.

The 2018 mission of the ExoMars programme in-

cludes a carrier Module and a Mars Rover developed

by ESA, and a Descent Module including a Surface

Platform developed by Roscosmos. The project is is

currently in Phase C/D and it is scheduled to be

launched by Proton in 2018.

DEIMOS Space has been involved in the Exomars

Programme (2016 and 2018 missions) since 2004

providing more than 10 years of technical activities in

the areas of End to End (from launch to landing) Mis-

sion Engineering and GNC.

In autumn 2015, the backup launch window of

2016 mission has been activated postponing the launch

to the period 14th-25th March 2016, replacing the

nominal launch window originally set in January 2016.

This paper presents the Mission Engineering activi-

ties performed by DEIMOS Space in support to Thales

Alenia Space Italia, acting as prime contractor for the

ExoMars2016 Mission. Support is dedicated to the

analysis of the Schiaparelli mission, from separation

from the TGO to landing, for the March 2016 launch.

The analyses presented cover the impact of the switch

to the back-up launch window and initial flight predic-

tions for the current launch day, from multiple aspects:

system margins identification through local entry corri-

dors analyses and 3DoF/6DoF End to End Monte Carlo

campaigns, verification of nominal ESA trajectories

and separation maneuver optimization for landing site

targeting, EDM aerodynamic database inspection and

Flying Qualities Analysis, and TGO-Schiaparelli geo-

metric visibility analyses.

All the analyses rely on DEIMOS Space state of the

art tools for Mission Engineering (PETbox, Planetary

Entry Toolbox [1] and LOTNAV, Low-Thrust Inter-

planetary Navigation Tool) whose results and design

methodology for Atmospheric Flight have been recent-

ly Flight Qualified through the successful ESA IXV

mission [2], in which DEIMOS Space was responsible

of the Mission Analysis and re-entry Guidance and

Control.

References:

[1] Bonetti D. et al (2016) “PETbox: Flight Quali-

fied Tools for Atmospheric Flight”, 6th

ICATT.

[2] Bonetti D. et al (2015) “IXV Mission Analysis

and Flight Mechanics: from design to postflight”,

AIDAA 2015.



mailto:[email protected]



EXOMARS SCHIAPARELLI ENTRY, DESCENT AND LANDING SYSTEM DESIGN, DEVELOPMENT AND POST-LAUNCH STATUS

O. Bayle1, L. Lorenzoni1, T. Blancquaert1, S. Langlois1, T, Walloschek1, S. Portigliotti2 and G. Passarelli2

1European Space Agency (ESTEC, Noordwijk, The Netherlands) 2Thales Alenia Space Italy (Torino, Italy).

The ExoMars 2016 Mission was launched on 14

March 2016 and constitutes the first mission of the ESA-Roscosmos joint programme for Mars explora-tion. The ExoMars 2016 mission includes the Trace Gas Orbiter (TGO) and the Schiaparelli module, which shall provide a demonstration of key technologies re-quired to safely land a payload on the surface of Mars:

- Heat Shield - Parachute System - Guidance, Navigation and Control System - Doppler Radar System for ground relative al-

titude and relative velocity measurement - Liquid Propulsion System for attitude control

and final braking - Crushable material for impact loads attenua-

tion Schiaparelli (also called EDL Demonstrator Mod-

ule – EDM) includes a package of sensors that will monitor the performance of the EDL subsystems in order to maximise the lessons learnt from this technol-ogy demonstration mission in preparation to the subse-quent mission that shall bring the ExoMars Rover to the Mars surface. In order to guarantee the return of the data gathered during the EDL, a robust communication strategy has been established between Schiaparelli and the ESA and NASA orbiters, which will allow the re-turn of the complete data set before the end of Schiapa-relli short lifetime on Mars surface.

Although designed to demonstrate EDL technolo-

gies, Schiaparelli also includes a science package that will operate on the surface of Mars for a short duration after landing, to perform meteorological measurements and characterize the Martian environment during dust storms period.

The paper provides an overview of the EDM mis-

sion and design and describes the last integration and test activities that have already been carried out before the launch. In particular, the paper describes the last tests performed on the integrated subsystems (para-chute system, propulsion system, RADAR system) and on Schiaparelli flight model. An outlook of the last integration activities is presented, in particular to de-

scribe the completion of the Heat Shield, which took place only a few days before the launch.

The paper provides also the status of the ExoMars

2016 mission during its course to Mars and the de-scription of the next steps of the mission. Schiaparelli will reach Mars on 19 October 2016, and will land in Meridiani Planum.

Finally, the papers gives an outlook of the Entry,

Descent and Landing systems that will be used for the following ExoMars Rover and Surface Platform mis-sion. The EDL systems used for that mission will shared between ESA and Roscosmos, ESA providing the Parachute System, the Guidance and Navigation system, the Doppler Radar System, the Inertial Meas-urement Unit, the Data Handling unit and the TT&C system.

Figure 1 – Schiaparelli and TGO before encapsula-

tion in Proton launcher fairing



MARS 2020 ENTRY, DESCENT, AND LANDING OVERVIEW. A. Chen1, P. Brugarolas1, E. Hines1, A. John-son1, R. Otero1, A. Stehura1, G. Villar1, D. Way2. 1Jet Propulsion Laboratory, California Institute of Technology (Pasadena, CA, 91009, [email protected]), 2NASA Langley Research Center (Hampton, VA 23681, [email protected])

Abstract: Building upon the success of Curiosity’s

landing and surface mission, the Mars 2020 project is a flagship-class science mission intended to address key questions about the potential for life on Mars and col-lect samples for possible return to Earth [1]. The mis-sion will also gather knowledge and demonstrate tech-nologies that address key challenges for future human expeditions to Mars. Based on the highly successful entry, descent, and landing (EDL) architecture from the Mars Science Laboratory (MSL) mission [2], Mars 2020 will launch in July of 2020 and land on Mars in February of 2021.

The mission takes advantage of the favorable 2020

launch/arrival opportunity; this enables the delivery of a larger, heavier, and more capable rover to wider vari-ety of potential landing sites. While Mars 2020 inher-its most of its EDL architecture, software, and hard-ware from MSL, a small number of changes have been made to correct deficiencies, improve performance, and increase the overall robustness of the system. The most significant of these changes is the recent addition to the baseline of a Terrain Relative Navigation (TRN) system, which will allow the vehicle to safely land at much more rugged and hazardous landing sites.

This paper presents an overview of the Mars 2020

EDL design and discusses the changes made as the project enters Phase C. Additionally, the paper also summarizes the Mars 2020 landing site safety assess-ment that is in progress in preparation for the next landing site selection workshop.

References: [1] Mustard, J., et al. (2013) “Report of the Mars

2020 Science Definition Team,” Tech. rep., Mars Ex-ploration Program Analysis Group (MEPAG). [2] Steltzner, A. (2013) “Mars Science Laboratory Entry, Descent, and Landing System Overview”, AAS 13-236.



HOW DOES TERRAIN RELATIVE NAVIGATION CHANGE THE MARS 2020 ENTRY, DESCENT, AND LANDING? D.W. Way1, S. Dutta2, A. Chen3, and P. Brugarolas4. 1NASA Langley Research Center (Hamp-ton, VA 23681, [email protected]), 2NASA Langley Research Center (Hampton, VA 23681, [email protected]), 3Jet Propulsion Laboratory (Pasadena, CA, 91009, [email protected]), and 4Jet Propulsion Laboratory (Pasadena, CA, 91009, [email protected]).

Abstract: The Mars 2020 project is a flagship-

class science mission to land the next robotic explorer on Mars. With a state-of-the-art suite of scientific in-struments, the new Curiosity-class rover will conduct a search for the evidence of past life, and for the first time, collect rock and soil samples for possible return to Earth [1]. Based on the highly successful Mars Sci-ence Laboratory (MSL) Entry, Descent, and Landing (EDL) architecture and the Sky Crane landing system [2], the new mission will launch in July of 2020 and will reach Mars in February 2021.

While Mars 2020 inherits most of its EDL architec-ture, software, and hardware from MSL, a few minor adjustments and improvements have been made to the EDL system design to either correct known issues from MSL or to improve the overall robustness of the system. The most significant of these changes is the recent addition to the baseline of a Terrain Relative Navigation (TRN) system, which will allow the vehi-cle to safely land at much more rugged and hazardous landing sites.

This TRN system fits nicely within the heritage MSL architecture by taking advantage of the post-separation propulsive divert maneuver performed to minimize the backshell re-contact risk. The TRN sys-tem consists of two main sub-systems: the Lander Vi-sion System (LVS) and the Safe Target Selection (STS). The LVS provides terrain-relative localization of the vehicle position by taking real-time camera im-ages while descending on parachute. These images are processed and co-registered to an on-board map, all on a dedicated compute element. This localized solution is then used within STS to determine a safe landing site that is reachable within the constraints of the pro-pulsive divert.

The presence of the TRN system allows the science community to propose landing sites that would other-wise be considered too risky. This alters slightly the careful balance of EDL risks inherent in the MSL sys-tem. This paper will focus on the minor adjustments made to the MSL EDL system to rebalance these risks in the presence of TRN.

References: [1] Mustard, J., et al. (2013) “Report of the Mars

2020 Science Definition Team,” Tech. rep., Mars Ex-ploration Program Analysis Group (MEPAG).

[2] Steltzner, A. (2013) “Mars Science Laboratory Entry, Descent, and Landing System Overview”, AAS 13-236. [3] Way, D. W., Davis, J. L, and Shidner, J. D. (2013) “Assessment of the Mars Science Laboratory Entry, Descent, and Landing Simulation”, AAS 13-420. [4] Way, D. W. (2013) “Preliminary Assessment of the Mars Science Laboratory Entry, Descent, and Landing Simulation”, IEEE-2013-2755.



TRN Performance in M2020. S. Mohan1, P. Brugarolas1, D. Way2, N. Trawny1, A. Stehura1, S. Dutta2, J. Mon-togmery1, A. Johnson1, A. Chen1 1NASA Jet Propulsion Laboratory, Calilfornia Institute of Technology (4800 Oak Grove Drive, Pasadena CA 91109), 2NASA Langley Research Center (8 Lindbergh Way, Hampton, VA 23681).

Abstract: The Terrain Relative Navigation (TRN) system is

an enabling Entry, Descent, and Landing (EDL) technology slated for inclusion in the Mars 2020 mission [1]. TRN provides real-time, autonomous, ter-rain-relative position determination and generates a landing target based on a priori knowledge of hazards. TRN is composed of the Lander Vision System (LVS) [2] and the Safe Target Selection (STS) algorithm [3]. The LVS generates a map-relative localization solution by fusing measurements from a visible-wavelength camera and an inertial measurement unit using the Map Relative Localization (MRL) algorithm operating on a high-performance compute element. Updated state knowledge is provided to the spacecraft navigation filter, which uses the STS algorithm to direct a divert maneuver away from known hazards within an onboard map.

The needs of Mars 2020 require TRN to have suffi-cient horizontal position accuracy to avoid hazards of 60m or less. The nominal performance reserves mar-gin on this and sub-allocates the remaining to three parts. The three parts are: the targetting accuracy based on the LVS map-relative localization [4], the knowledge error from the time of localization to the ground, and the control error of the vehicle with re-spect to the reference trajectory. A reduced case per-formance is also flowed down with no margin for fault conditions that sub-allocates the entire 60m to the three parts. This paper presents the error budget structure and sub-allocations for both the nominal and reduced cases. Preliminary design results are presented that show current best estimate performance of 31m, more than 30% to the 60m requirement.

[1] Allen Chen et al. (2015) 2015 Update: Mars

2020 Entry, Descent, and Landing System Overview, IPPW12 Presentation #2104.

[2] Aaron Stehura et al. (2015) The Future of Land-ing: Terrain Relative Navigation From Prototype to Mars 2020, IPPW12 Presentation #3104.

[3] Paul Brugarolas et al. (2015) On-Board Ter-rain Relative Guidance-Target Selection for the Mars 2020 Mission, IPPW12 Presentation #3105.

[4] Andrew Johnson et al. Design and Analysis of Map Relative Localization for Access to Hazardous

Landing Sites on Mars, AIAA SciTech, San Diego CA 2016.

CL#16-1172



ESA’s Phobos Sample Return Mission. T. Voirin1, J. Larranaga2, J. Romstedt1, D. Koschny1, D. Rebuffat1 1 ESA-ESTEC ([email protected]), 2AURORA B.V. for ESA/ESTEC ([email protected]).

Introduction: ESA has just concluded a 1 year

phase A system study for a Phobos Sample Return Mission (PhSR). The main scientific goal of PhSR is to discriminate between the various candidate theories explaining Phobos formation : impact, co-formation and capture. Meeting this goal requires bringing back to Earth at least 100g of Phobos regolith for extensive laboratory analyses. This is the main mission require-ment for PhSR.

The PhSR S/C has a total mass at launch of ~ 5 tons and is a stack composed of 4 elements : the Pro-pulsion Module, the Landing Module (carrying the scientific payload), the Earth Return Vehicle, itself carrying the Earth Re-entry Capsule (ERC) in which the sample will be encapsulated. The S/C includes a comprehensive payload composed of several remote sensing instruments (Wide Angle Camera, Narrow angle Camera, Mid-IR and Near IR spectrometers), used for Phobos characterization, and a surface pack-age composed of a Stereocamera (STCAM), a Close-up imager (CLUPI), and the Sample Acquisition and Containment System in charge of collecting, verifying, sealing and inserting the sample in the ERC.

Mission Overview The PhSR mission foresees a launch in 2025 on the

Ariane 5 or 6 launcher, covering a total mission dura-tion between 3 and 5 years, depending on the selected launcher. After Mars Orbit Insertion, a series of ma-noeuvres are performed to phase the orbit with Phobos orbit around Mars. The Propulsion Module is jetti-soned afterwards. A 3-months phase of Phobos global characterization follows, using a quasi-satellite orbit (QSO) around Phobos, which allows mapping of more than 50% of its surface at 3m spatial resolution. During this phase, on top of the scientific observation, exten-sive radio-tracking orbit determination will be per-formed, supported by the acquisition of navigation images and the build-up of a landmarks database. This allows to reach unprecedented accuracy in the knowledge of Phobos gravity field and ephemeris, and of the knowledge of S/C position.

Based on the acquired images, 3 candidate landing sites will be selected by the ground team, involving scientists and engineers. The S/C will then perform one low altitude flyby (5 km) over each candidate landing site to allow for local characterization at 15 cm spatial resolution. These observations will allow the ground team to select the highest priority landing site among the three candidates.

A transfer manoeuvre then brings the S/C from the QSO to a “gate” located 5 to 10 km above the selected landing site, and from where a closed-loop controlled descent follows. The last 50m of the descent are per-formed in free-fall to limit the contamination of the sampling area by the propulsion system. The landing occurs at less than 1 m/s vertical velocity, and with a dispersion of 50m (at 95% confidence). Due to the low gravity of Phobos, hold-down thrusters are used during touch down to ensure the S/C stability on the surface.

Once on the surface, the sampling area reachable by the robotic arm is imaged by STCAM, providing a 1 cm spatial resolution. This allows the science team to pre-select 3 candidate sampling points within the reachable area. A CLUPI image of each of the candi-date sampling points is then acquired, providing 300 µm spatial resolution. This resolution allows the scien-tists to select the highest priority sampling point (en-suring for instance diverse types of grains,e.g. pebbles are present within the sampled area). In total, the deci-sion-making process including S/C operations for the selected sampling point can take up to a few weeks. Once selected, a complete CLUPI scan around the sampling point is performed at 100 µm spatial resolu-tion. This operation will be repeated after the sampling and will allow, by observing the macroscopic defor-mation caused by the sampling procedure on the sur-roundings, to infer properties on the Phobos soil struc-ture. The sampling itself will be performed by the sampling tool, of either a corer-type or a rotary brush. After the sampling verification, the sample will be sealed and inserted into the ERC.

After up to 1 month on the Phobos surface, the lift-off of the ERV will be triggered. Ultimately, the ERV is injected into a Mars-Earth transfer interplanetary orbit. The ERC will be released shortly before arrival at Earth vicinity to perform a direct entry into Earth atmosphere. To be representative of a potential Mars Sample Return mission capsule, it has been decided that the ERC would not have any parachute system, and would perform a hard landing in Woomera (Aus-tralia). The impact energy is absorbed by a crushable material, which allows the sample to remain within acceptable g-load levels (<2,000g). The ERC will then be localized by a beacon, retrieved and transferred to a Sample Receiving Facility.

Note that an alternative PhSR scenario in coopera-

tion with Roscosmos has been studied during the phase A, but this paper focuses on the ESA-only scenario.



THE PSYCHE MISSION: EXPLORING A METAL WORLD FOR THE FIRST TIME. L.T. Elkins-Tanton1, E. Asphaug2, J. Bell2, D. Bercovici3, B.G. Bills4, R.P. Binzel5, W.F. Bottke6, J. Goldsten7, R. Jaumann8, I. Jun4, D.J. Lawrence7, S. Marchi6, D. Oh4, R. Park4, P.N. Peplowski7, C.A. Polanskey4, T.H. Prettyman10, C.A. Raymond4, C.T. Russell11, B.P. Weiss5, D.D. Wenkert4, M. Wieczorek9, M.T. Zuber5, 1School of Earth and Space Exploration, Ari-zona State University, 781 Terrace Rd., Tempe AZ 85287, [email protected], 2ASU, 3Yale, 4JPL, 5MIT, 6SwRI, 7APL, 8DLR, 9IPGP, 10PSI, 11UCLA.

Introduction: Psyche is a Discovery-class mis-

sion, selected for a Step 2 concept study, to investigate an exposed metal planetary core. Our target is the large asteroid Psyche (~240 x 185 x 145 km) that orbits at 3 AU. It is made almost entirely of Fe-Ni metal, as indi-cated by: • High radar albedo of 0.42 [1] • Thermal inertia of ~120 J m-2 S-0.5 K-1 [2] (Ceres,

Pallas, Vesta, Lutetia are all 5 to 30 J m-2 S-0.5 K-1) • Density estimates of 6,980 ± 580 kg m-3 [3], 6,490 • ± 2,940 kg m-3 [4, 5], and 7,600 ± 3,000 kg m-3 [6].

A 0.9 µm absorption feature suggests 10% of Psy-che’s surface is high-magnesian orthopyroxene [7].

Psyche may be: • A larger planetesimal’s exposed core, once molten,

that solidified either inside-out or outside-in, and is now either intact or now broken into a rubble pile;

• Not a core, but instead highly reduced, primordial metal-rich materials that accreted, but never melted.

Hit-and-run collisions could create Psyche: De-spite living on this planet and being able to study it more closely than any other, we continue to revise our models of Earth’s core, in part because we cannot see

or measure the core directly. Psyche offers a unique window into the violent history of collisions and accre-tion that created the planets and their cores.

Meteorite geochronology reveals that metal cores formed within the first half million years [8]. Meteor-ites also reveal that many differentiated bodies, includ-ing iron meteorite parent bodies, produced magnetic dynamos [9-11]. High-energy impacts were ubiquitous in the early solar system, so cores likely formed and reformed repeatedly.

Models show that there were many destructive “hit and run” impacts that could strip the silicate mantle from differentiated bodies, leaving an exposed metal core. This is the leading hypothesis for Psyche’s for-mation (Fig. 1). Psyche is the only asteroid that will yield substantial information about metal cores (other metallic asteroids are far smaller and not roughly spherical).

The Psyche investigation has three broad goals: 1. Understand a previously unex-

plored building block of planet for-mation: iron cores.

2. Look inside the terrestrial plan-ets, including Earth, by directly exam-ining the interior of a differentiated body, which otherwise could not be seen.

3. Explore a new type of world. For the first time, examine a world made not of rock, ice, or gas, but of metal.

Psyche mission objectives: A. Determine whether Psyche is a core, or if it is unmelted material. B. Determine the relative ages of re-gions of its surface. C. Determine whether small metal bod-ies incorporate the same light elements as are expected in the Earth’s high-pressure core. D. Determine whether Psyche was formed under conditions more oxidiz-ing or more reducing than Earth’s core.

E. Characterize Psyche’s topography. We will meet these objectives by examining Psyche with three high heritage instruments and radio science:

Fig 1: Discovery class investigation of Psyche. The mission plan in-cludes solar electric cruise, arrival at Psyche in 2026, and 12 months of science operations.



1. Multispectral imagers (MSL Mastcam heritage)

with clear and seven color filters provide surface geol-ogy, composition, and topographic information [12].

2. A gamma-ray and neutron spectrometer (MESSENGER heritage) determines the elemental composition for key elements (e.g., Fe, Ni, Si, and K) as well as compositional heterogeneity across Psyche’s surface [13, 14].

3. Dual fluxgate magnetometers characterize the magnetic field [15].

4. Radio science will map Psyche’s gravity field using the X-band telecomm system.

Synthesis and Expected Outcomes: If our magne-tometer detects a coherent dipolar field, then Psyche had a core magnetic dynamo and solidified outside-in, allowing the cold solid exterior to record the magnetic field [16]. We would then expect to find Ni content of ~4 wt% (or slightly lower if diluted with other materi-al), consistent with the first solidifying metal in a frac-tionating core. Nickel of 6–12 wt% indicates the sur-face was the last material to solidify and thus the core solidified inside-out. We would expect no remanent magnetic field, since there would have been no cool surface material to record the field while the dynamo was working (Fig. 2).

If we find very low nickel content, and no coherent magnetic field, then we may arrive at perhaps the most exciting hypothesis: Psyche never melted, but consists of highly reduced, primordial metal. This hypothesis would be further supported by the discovery of no mantle silicates, but instead reduced silicates mixed on a small scale throughout the surface. The likeliest place for such material to exist is closest to the Sun in the early disk, where temperatures are very hot (reducing) and light elements are volatilized away, leaving heavy elements and metals. This outcome would support the hypothesis of Bottke et al. [17], that such bodies were injected into the asteroid belt from the innermost solar system. This kind of migration has been little consid-ered.

If we find a coherent dipolar magnetic field and ei-ther higher or lower average surface nickel content, then we have found something unexpected based on existing models for small core formation.

If we discover that Psyche has a magnetic field, then we will have detected in situ magnetization at an asteroid for the first time. The increasing evidence that some planetesimals had magnetic dynamos requires that they had convecting metallic cores, but our under-standing of the ways they solidify makes modeling their dynamos difficult. If Psyche was a core and solid-ified from the outside inward, it is an analog for Mer-cury’s and Ganymede’s cores in the present day, which may be solidifying this way [18]. This unexpected pro-cess could be observed on Psyche as can never be done on Mercury. Solidification inside out, in contrast, par-allels the Earth’s core.

References: [1] Shepard et al. (2010) Icarus, 208, 221. [2] Matter et al. (2013) Icarus, 226, 419. [3] Kuzmanoski & Koraccević (2002) Astron. & Astro-phys., 395, L17. [4] Baer et al. (2011) Astronom. J, 141, 1. [5] Lupishko (2006) Solar Sys. Res., 40, 214. [6] Shepard et al. (2008) Icarus, 195, 184. [7] Harder-sen et al. (2005) Icarus, 175, 141. [8] Scherstén, et al. (2006) EPSL, 241, 530. [9] Tarduno et al. (2012) Sci-ence, 338, 939; [10] Elkins Tanton et al. (2011) EPSL, 305, 1. [11] Bryson et al. AGU abstract (2015). [12] Bell et al., 47th LPSC, Abstract #1366 (2016). [13] Peplowski et al., 47th LPSC, Abstract #1394 (2016). [14] Lawrence et al., 47th LPSC, Abstract #1622 (2016). [15] Weiss et al., 47th LPSC, Abstract #1661 (2016). [16] Scheinberg et al., this LPSC (2016). [17] Bottke et al. (2006) Nature, 439, 821. [18] Hauck et al. (2013) JGR, 118, 1204.

Fig. 2. Instrument measurements allow hy-pothesis discrimination. Ni content and mag-netic field shows both measurement margin outside of expected models and utility of mul-tiple instruments addressing the same hypoth-eses. Ni below 4 wt% is not detectable by our instruments, but we will use magnetic field measurement, silicate domain size, and oxida-tion state to discriminate between the two low-Ni models.



OVERVIEW OF THE ASTEROID REDIRECT MISSION (ARM). D. D. Mazanek1, P. A. Abell2, D. M.

Reeves1, P. W. Chodas3, M. M. Gates4, R. L. Ticker4, and L. N. Johnson5, 1Systems Analysis and Concepts Direc-

torate, NASA Langley Research Center ([email protected]), 2Astromaterials Research and Exploration

Science Division, NASA Johnson Space Center, 3Center for Near-Earth Object Studies, Jet Propulsion Laboratory, 4Human Exploration and Operations Mission Directorate, NASA Headquarters, 5Planetary Defense Coordination

Office, NASA Headquarters.

Background: To achieve its horizon goal of send-

ing humans to Mars, the National Aeronautics and

Space Administration (NASA) plans to proceed in a

series of incrementally more complex human space-

flight missions. Today, human flight extends only to

Low-Earth Orbit (LEO), and should problems arise

during a mission, the crew can return to Earth in a mat-

ter of hours. The next step comprises cis-lunar missions

which provide a “proving ground” for the testing of

systems and operations while still accommodating an

emergency return path to the Earth of several days. Cis-

lunar proving ground mission experience will be essen-

tial for more ambitious human missions beyond the

Earth-Moon system, which will require months, or

even years of transit time. In addition, NASA has been

given a Grand Challenge to “find all asteroid threats to

human populations and know what to do about them.”

Obtaining knowledge of asteroid physical properties

and performing asteroid deflection technique demon-

strations for planetary defense provide much needed

information to address the mitigation of potentials as-

teroid impacts with Earth.

Mission Description: NASA’s Asteroid Redirect

Mission (ARM) is a capability demonstration mission

that combines robotic and crewed segments to develop,

test, and utilize a number of key capabilities that will

be needed for future exploration of Mars and other

Solar System destinations, as well as providing other

broader benefits. ARM consists of two mission seg-

ments: 1) the Asteroid Redirect Robotic Mission

(ARRM), the first robotic mission to visit a large

(greater than ~100 m diameter) near-Earth asteroid

(NEA), collect a multi-ton boulder from its surface

along with regolith samples [1], demonstrate a plane-

tary defense technique known as the Enhanced Gravity

Tractor (EGT) [2], and return the asteroidal material to

a stable orbit around the Moon; and 2) the Asteroid

Redirect Crewed Mission (ARCM), in which astro-

nauts will take the Orion capsule to rendezvous and

dock with the robotic vehicle, conduct multiple extra-

vehicular activities to explore the boulder, and return to

Earth with samples. NASA’s proposed ARM concept

would leverage several key ongoing activities in human

exploration, space technology, and planetary defense.

The ARRM is planned to launch at the end of 2021,

which would likely place the ARCM in 2026.

Mission Objectives: The Asteroid Redirect Mis-

sion is designed to address the need for flight experi-

ence in cis-lunar space and provide opportunities for

testing the systems, technologies, and capabilities that

will be required for future human operations in deep

space. The highest priority objective of ARM is to

conduct a human spaceflight mission involving in-

space interaction with a natural object, in order to pro-

vide the systems and operational experience that will

be required for eventual human exploration of the Mars

system, including the Martian moons Phobos and Dei-

mos. The second primary objective of ARM is the de-

velopment of a high-power Solar Electric Propulsion

(SEP) vehicle, and the demonstration that it can oper-

ate for many years in interplanetary space, which is

critical for deep-space exploration missions. By trans-

ferring the multi-ton asteroid boulder to lunar vicinity,

ARRM will demonstrate the ability for SEP-based

spacecraft to transport massive objects such as crew

habitats, landers, or interplanetary cargo. ARRM will

also conduct proximity operations with a natural space

object in a low-gravity environment. Using sensors and

high-speed processing, the ARRM spacecraft will sur-

vey the asteroid surface, navigate to the selected land-

ing site and boulder, and autonomously capture the

target boulder using dexterous robotics. These autono-

my and dexterous robotics capabilities may be em-

ployed for future Mars logistics and in-situ resource

utilization, as well as science sample return. The

ARCM provides a focus for the early flights of the

Orion program, which will take place before the infra-

structure for more ambitious flights will be available.

Astronauts will participate in the scientific in-space

investigation of nearly pristine asteroid material, at

most only minimally altered by the capture process.

The ARCM will provide the opportunity for human

explorers to work in space with asteroid material, test-

ing the activities that would be performed and tools

that would be needed for later exploration of primitive

body surfaces in deep space. The operational experi-

ence would be gained close to our home planet, making

it a significantly more affordable approach to obtaining

this experience. The combined objectives of human

exploration and planetary defense, along with the

knowledge gained and operational experience that will

benefit the scientific and asteroidal resources commu-

nities, provide a broad-based rationale for the ARM.



Following completion of joint ARRM-ARCM opera-

tions, the ARRM spacecraft could possibly be refueled

and reused as an infrastructure element such as space-

based “tug” or power source, or to conduct additional

small body exploration.

Target Asteroid Candidates: NASA has identi-

fied the NEA (341843) 2008 EV5 as the reference tar-

get for the ARRM, but is also carrying three other

NEAs as potential options [(25143) Itokawa, (162173)

Ryugu, and (101955) Bennu]. Additionally, the near-

Earth object observations program continues to search

for potential candidates. The final target selection for

the ARRM will be made approximately a year before

launch, but there is a strong recommendation from the

scientific and resource utilization communities that the

ARM target be volatile and organic rich. Three of the

current candidates are carbonaceous NEAs. Specifical-

ly, the ARRM reference target, 2008 EV5 is a carbona-

ceous (C-type) asteroid that has been remotely charac-

terized (via visual, infrared, and radar wavelengths), is

believed to be hydrated, and provides significant return

mass potential (with evidence for boulders on the sur-

face greater than 20 metric tons). It also has an ad-

vantage in that the orbital dynamics of the NEA fall

within the current baseline mission timeline of five

years between the launch of the ARRM and the launch

of the ARCM to allow for the round trip return of the

robotic vehicle to cis-lunar space. Therefore, NEA

2008 EV5 provides a valid target that can be used to

help with formulation and development efforts.

Input to ARM and Future Plans: In the fall of

2015, NASA established the Formulation Assessment

and Support Team (FAST), which was chartered by

NASA to provide timely inputs for mission require-

ment formulation in support of the ARRM Require-

ments Closure Technical Interchange Meeting (TIM) in

mid-December of 2015, to assist in developing an ini-

tial list of potential mission investigations, and to pro-

vide input on potential hosted payloads and partner-

ships that could be provided by domestic and interna-

tional partners. Expertise from the science, engineer-

ing, and technology communities was represented by

exploring lines of inquiry related to key characteristics

of the ARRM reference target asteroid (2008 EV5) for

engineering design purposes. As of December 2015,

the FAST has been formally retired and the FAST final

report was publically released in February of 2016 [3].

However, plans have been made to stand up an ARM

Investigation Team (IT), which is expected be formed

in 2016. The multidisciplinary IT will assist with the

definition and support of mission investigations, sup-

port ARM program-level and project-level functions,

provide technical expertise, and support NASA Head-

quarters interactions with the technical communities

through mission formulation, mission design and vehi-

cle development, and mission implementation. Add-

tionally, NASA plans to provide opportunities for addi-

tional contributed hardware payloads and associated

investigations to be included as part of the ARRM.

References: [1] Mazanek D. D., Merrill R. G.,

Belbin S. P., Reeves D. M., Earle K. D., Naasz B. J.,

and Abell P. A. (2014) Asteroid Redirect Robotic Mis-

sion: robotic boulder capture option overview.

AIAA/AAS Astrodynamics Spec. Conf., San Diego.

[2] Mazanek, D. D., Reeves, D., Hopkins, J., Wade,

D., Tantardini, M., and Shen, H. (2015) “Enhanced

Gravity Tractor Technique for Planetary Defense,” 4th

IAA Planetary Defense Conference − PDC 2015, Fras-

cati, Roma, Italy. [3] Mazanek, D. D., et al. (2016).

“Asteroid Redirect Mission (ARM) Formulation As-

sessment and Support Team (FAST) Final Report.”

NASA/TM–2016-219011.



ROSETTA STAR TRACKERS IN THE COMET DUST : UNDERSTANDING AND IMPROVING THE

FLIGHT BEHAVIOUR THROUGH ON-GROUND TESTING OF THE STR EQM WITH THE

MICROSTOS OPTICAL STIMULATOR.

P. Regnier1, P. Vidal

1 and S. Lodiot

2, J-L Pellon-Bailon

2,

1Airbus Defence & Space ([email protected],

[email protected],), 2ESOC ([email protected], [email protected]).

Introduction: The Rosetta probe reached its des-

tination comet Churyumov-Gerasimenko in spring

2014 after a ten-year long journey through outer space.

After releasing the Philae lander on November 12th

of

that year, the European Space Operations Center

(ESOC) commanded the Rosetta orbiter to lower its

orbit to perform low altitude fly-bys for enhanced sci-

ence. However at that time the comet outgassing activi-

ty started to become burdensome to the spacecraft star

trackers and the Attitude and Orbit Control System

(AOCS) attitude estimation function, up to the point of

triggering a safe mode in march 2015.

Then, as anticipated, the situation did not improve

towards the comet perihelion passage in august 2015,

forcing ground operators to retreat the Rosetta orbiter

further away from the comet in order to preserve its

precious attitude estimation function from the hazard-

ous comet dust environment.

As the designer and manufacturer of the Rosetta

orbiter, Airbus Defence and Space proposed to ESOC

an original engineering support and in-flight expertise

trying to better characterize and potentially improve

the in-flight behaviour, through an on-ground testing

campaign of the 15-year old Rosetta Star Tracker En-

gineering and Qualification Model (EQM) connected

to the spacecraft EQM at ESOC, with a specially

adapted in-house Optical Stimulator named the mi-

croSTOS.

This presentation will first describe the observed at-

titude estimation in-flight behavior, then present the

proposed AOCS SW improvements before detailing

the Rosetta EQM test phase carried out at ESOC end

2015, and the obtained results.

Comet dust effects on Star Trackers and atti-

tude estimation : although the Rosetta star tracker

software was developed from the beginning with spe-

cial measures to improve the robustness of the lost-in-

space acquisition and tracking modes to comet dust

environment, actual conditions encountered at low alti-

tudes (illustrated in the attached STR CCD image)

have generated STR anomalies such as transient lock-

ing on false stars resulting in Failure Detection Isola-

tion and Recovery (FDIR) actions and safe mode trig-

gering. Attitude off-pointing was also observed as a

consequence of transient locking on false stars.

Proposed improvements and on-ground tests :

The AOCS SW improvements proposed by Airbus

Defence and Space consisted in a tightening of the gy-

ro-stellar innovation threshold based on empirical in-

flight TM results, together with an enlarging of the

corresponding FDIR surveillance, in order to better

isolate the attitude estimation function from false stars

locking at STR level. However the limited Rosetta TM

observability and the limitations in the available 15-

year old simulation test benches did not allow to gain

enough confidence in the adequation of these proposed

SW modifications. Therefore Airbus DS proposed to

use a powerful optical stimulator (the in-house mi-

croSTOS) in front of the Rosetta Star Tracker EQM to

exercise the clones of the real in-flight STR and AOCS

SW in order to try to reproduce the in-flight behavior

and validate the efficiency and safety of the proposed

SW modifications. This raised many challenges such as

reviving a STR optical head HW unit never used since

15 years, by-passing Rosetta EQM simulation limita-

tions, adapting the microSTOS SW to add the simula-

tion of dust and the microSTOS HW to fit with the old

STR HW, and various iterations necessary to achieve

valuable results, notably locking the STR on false stars

before losing tracking.







MicroSOS installa-

tion on the Rosetta

EQM Optical Head

Test Results and Conclusions : At the end, the in-

flight complex behavior could be reproduced, especial-

ly the FDIR triggering and the attitude off-pointing as

observed in march 2015. Simulations done with the

proposed SW modifications exhibited no FDIR trigger-

ing and much less attitude off-pointing, showing a po-

tential benefit for more in-flight robustness in the com-

et dust environment. However since the testing has

been made, the comet outgassing has much decreased,

making the SW modifications less useful. This may

change near the end-of-mission when very low altitude

orbits will be flown by the orbiter before its planned

final touchdown.



EARTH ENTRY VEHICLE DESIGN FOR COMET SURFACE SAMPLE RETURN. T. R. White1, R. W. Maddock2, C. D.

Kazemba3, R. G. Winski4, J. A. Samareh2, D. S. Adams5, 1NASA Ames Research Center, Moffett Field, CA, 94035, [email protected] 2NASA Langley Research Center, Hampton, VA, 23681, [email protected]

3STC Corporation, NASA Ames Research Center, Moffett Field, CA, 94035, [email protected] 4Analytical Mechanics Associates, Inc., Hampton, VA, 23681, [email protected] 5Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, [email protected]

Introduction: The 2013 Decadal Survey for New

Frontiers missions identifies several high-value science

missions, including Comet Surface Sample Return

(CSSR) [1]. The goal of a CSSR mission is to advance

the scientific community’s fundamental understanding

of the origin of the solar system and the contribution of

comets to the volatile inventory of the Earth. The

CSSR mission has several fundamental scientific re-

quirements to meet this goal. CSSR would acquire and

return to Earth for laboratory analysis a macroscopic (≥

500 cc) sample from the surface of a comet nucleus.

The sample would be collected with a technique that

preserves complex organics and stored to prevent any

aqueous alteration of the sample.

Once the sample is in a laboratory on Earth, the

sample would be analyzed to determine the nature of

cometary matter. An entry capsule, or earth entry ve-

hicle (EEV), would be required to protect the scientific

payload from the extreme conditions of atmospheric

entry, descent, and landing.

The Decadal Survey Mission Concept Study [2],

along with an APL 2007-2008 Comet Surface Sample

Mission Study [3] details several of the driving re-

quirements for a CSSR EEV; these include a payload

volume and mass and inertial entry velocity of ~ 9

km/s. The mission concept study selected a Multi-

Mission Earth Entry Vehicle (MMEEV) design con-

cept derived from the Mars Sample Return (MSR) en-

try capsule design because of its increased reliability

over a parachute-based vehicle [4], [5]. This presenta-

tion will explore the entry vehicle design space associ-

ated with a CSSR mission, including trajectory options,

aerothermal environments, terminal descent conditions,

and thermal protection system materials.

References:

[1] National Research Council, “Visions and Voy-

ages for Planetary Science in the Decade 2013-2022,”

The National Academies Press (2011). [2] Veverka, J.,

Johnson, L., Reynolds, E., “Mission Concept Study:

Comet Surface Sample Return (CSSR) Mission,” Pre-

pared for the Planetary Science Decadal Survey

(2011). [3] The Johns Hopkins University Applied

Physics Laboratory, “Comet Surface Sample Return

Mission Study,” Prepared for NASA’s Planetary Sci-

ence Division (2008). [4] Maddock, R. W., “Multi-

Mission Earth Entry Vehicle Design Trade Space and

Concept Development Status,” 7th International Plane-

tary Probe Workshop (2010). [5] Maddock, R., Hen-

ning, A., Samareh, J., “Passive vs. Parachute System

Architecture for Robotic Sample Return Vehicles,”

IEEE Aerospace Conference (2016).








Saturn PRobe Interior and aTmosphere Explorer (SPRITE). A. A. Simon1, D. Banfield2, D. Atkinson3, S. Atreya4, W. Brinckerhoff1, A. Colaprete5, A. Coustenis6, L. Fletcher7, T. Guillot8, M. Hofstadter9, J. Lunine2, P. Mahaffy1, M. Marley5, O. Mousis10, T. Spilker11, M. Trainer1, C. Webster9. 1NASA Goddard Space Flight Center, 2Cornell University, 3Univ. Idaho, 4Univ. Michigan, 5NASA Ames Research Center, 6LESIA, Observ. Paris-Meudon, CNRS, Paris Univ. 6 and 7, France, 7Univ. Leicester, 8Observatoire de la Cote d'Azur CNRS / Laboratoire Cassiopée, 9Jet Propulsion Laboratory, 10Laboratoire d'Astrophysique de Marseille, 11Independent Consultant

Introduction: The Vision and Voyages Planetary

Decadal Survey identified a Saturn Probe mission as one of the high priority New Frontiers mission targets [1]. Many aspects of the Saturn system will not have been fully investigated at the end of the Cassini mis-sion, because of limitations in its implementation and science instrumentation. Fundamental measurements of the interior structure and noble gas abundances of Saturn are needed to better constrain models of Solar System formation, as well as to provide an improved context for exoplanet systems. The SPRITE mission will fulfill the scientific goals of the Decadal Survey Saturn probe mission. It will also provide ground truth for quantities constrained by Cassini and conduct new investigations that improve our understanding of Sat-urn’s interior structure and composition, and by proxy, those of extrasolar giant planets.

Key Science Questions: At the end of its 13-year mission, Cassini will have extensively studied Saturn’s upper atmosphere (troposphere to ionosphere) through a mix of imaging, spectroscopy, occultations, and other means. It will also have provided some gravity con-straints on its core size. However, the answers to sev-eral questions remain elusive, simply because Cassini was not designed to address them. Among these are:

1. What are the noble gas abundances? The abundance of helium, in particular, is needed to understand where (and when) Saturn formed, and how it has continued to evolve. [2,3,4]

2. What is the deep water abundance? Water is key to convective processes, and is governed by where Saturn formed and planetesimal de-livery. [4,5]

3. What is Saturn’s deep interior structure? The presence of a core, and any layered structure, is also determined during formation and tests instability models in the protosolar nebula. [4, 6]

SPRITE: The SPRITE mission will address these measurements primarily through delivery of an atmos-pheric entry probe. A probe allows direct measure-ment of composition and atmospheric structure along its descent path. This provides information on regions that were not accessible to Cassini remote sensing measurements, and provides ground truth of retrieved tropospheric parameters. In addition to temperature,

pressure and wind velocities, some quantities are even more difficult to constrain from remote sensing. For example, although analytical methods have attempted to determine helium abundance, they are dependent on model assumptions and can only place limits on the actual value to within the fidelity of those assumptions. A probe will provide an absolute direct measurement that can be used to validate the accuracy of these methods. This will determine if helium abundance can be reliably retrieved from remote sensing data for other planets, to better inform formation models.

References: [1] Vision and Voyages for Planetary Science in

the Decade 2013-2022, Space Studies Board, ISBN: 978-0-309-22464-2

[2] Ben-Jaffel, L. and I. Abbes 2015. J. Phys.: Conf. Ser. 577, 012003

[3] Encrenaz, T. 1990 Rep. Prog. Phys. 53, 793 [4] Guillot, T. 2005 Annual Review of Earth and

Planetary Sciences 33, 493 [5] Wang, D. et al. 2015 Icarus 250, 154 [6] Helled, R. et al. 2014. Giant Planet Formation,

Evolution, and Internal Structure in Protostars and Planets VI, U. Arizona Press.

Credit: T. Balint



THE BEE: A BIOSIGNATURE EXPLORER TO SAMPLE PLUMES OF OCEAN WORLDS. P. R. Ma-haffy1, R. Arevalo1, S. K. Atreya2, M. Benna3, W. B. Brinckerhoff1, R. Danell4, J. P. Dworkin1, J. Eigenbrode1, C. Freissinet5, J. Garvin1, S. Getty1, D. P. Glavin1, T. Hoehler6, T. Hurford1, R. Lorenz7, J. Nuth1, M. Ravine8, P. Spi-daliere1 and R. Summons9. 1NASA Goddard Space Flight Center, Code 690, Greenbelt, MD 20771 ([email protected]), 2AOOS Dept., University of Michigan, Ann Arbor, MI 48189, 3CRESST, University of Maryland Baltimore County, Baltimore, MD 21228, 4Danell Consulting, Winterville, NC 28590, 5CRESST, University of Maryland Baltimore County, Baltimore, MD 21228, 6NASA AMES Research Center, Moffett Field, CA 94035, 7Johns Hopkins University, Laurel, Maryland 20723, 8Malin Space Science Systems, San Diego, CA 92191, 9MIT, Cambridge, MA 02139.

Introduction: The possibility of the presence of

life in ocean worlds in our solar system is a compelling driver for a detailed exploration of icy satellites of the giant planets such as Europa, Titan, and Enceladus in the decades ahead. A variety of energy sources may exist to support microbial life in these environments (Figure 1), leaving both free organic molecules and cellular material in the ocean waters. We here describe the Biosphere Explorer for Europa (BEE) that was designed at Goddard Space Flight Center (GSFC) in response to a directive from NASA to explore options for possible augmentations to the Europa Multi Flyby Mission (EMFM) mission to directly search for life at

Europa. The EMFM investigations were selected to study the habitability of that moon but not to directly search for extant life. In response to this challenge to extend these investigations the BEE was designed as a probe to be released from the EMFM, to actively target and fly through a plume at a nominal altitude of 5 km, collect material, and then search for molecular signa-tures of life in these gas and icy particles vented into space from Europa’s interior ocean. Regardless of the archecticture ultimately selected for exploration of Europa with the EMFM mission, the BEE study pro-vides a case study example of how a robust search for signs of life may be realized on targets such as Encela-

Figure 1. Cartoon of possible sources of energy and nutrients at ocean/mantle and ice/water boundaries, radiation processes and mixing with exogeneous material at the surface. The BEE approach to fly through an active plume and secure a taste of samples that moments before might have been in a liquid environment provides a direct search for biosignatures and avoids the cost and risk of landing on the surface.



dus or Europa without incurring the risk and cost of landing on the icy surface of an ocean world.

Characteristics of Molecular Biosignatures: A range of molecular biosignatures give evidence of ex-tinct or extant life in terrestrial environments. These include [e.g. 1] patterns in the distribution of molecular weights of organic compounds that are structurally related, patterns of repeating units, structural prefer-ence for chain rather than branched compounds, enan-tiomeric excesses, and distinct isotopic signatures of biological activity. In fact, analog studies have shown that it is even possible to distinguish between a living biota, a recently extinct biota, a long extinct biota or an abiotic environment by looking at the distribution of the organic molecules present in the sample [e.g., 2,3]. For example, the presence of phosphoric acid and nu-cleobases in Lake Hoare samples from Antarctica sug-gest a living biota from the presence of DNA. The ter-restrial building blocks of nucleobases, proteins, and ultimately RNA and DNA are amino acids and the building blocks of cell walls are fatty acids and their derivatives. The presence of a wide range of amino and carboxylic acids reveals a recently extinct to extant biota, while the presence of the more robust carboxylic acids (fatty acids) with repetitive masses or with higher abundance of molecules with an even number of car-bon suggests remnants of a long-time extinct biota.

Synergy of Separation and Mass Spectrometer Techniques: Liquid or gas separation techniques com-bined with mass spectrometric analysis are the tool of choice for definitive identification of organic mole-cules in terrestrial environments. Either technique alone leaves ambiguity in the chemical analysis nec-essary for definitive identification of molecular bi-osignatures. For space applications, a gas chromato-graph mass spectrometer (GCMS) is the most robust tool. The GCMS technique has been successfully im-plemented on the Sample Analysis at Mars (SAM) instrument in the Curiosity Rover with the first in situ detection of organic molecules on this planet [4]. A GCMS based on an advanced ion trap mass spectrome-ter is presently being developed for the ExoMars mis-sion [5]. Its sensitivity in the GCMS mode is compara-ble to that of high end laboratory instrumentation and exceeds that of other mass spectrometers developed for space applications.

Thermochemolysis, Enatiomeric Separation of Chiral Compounds, and Tandem Mass Spectrome-try for Definitive Identification of the Molecules of Life: Chemical transformation of a polar molecule into a more volatile product molecule by introduction of a suitable reagent, is necessary to analyze the widest possible range of the molecules of life (amino acids, amines, sugars, and carboxylic acids) by GCMS tech-

niques. With efficient transformation of these mole-cules into species that are readily detected by a GCMS, patterns in molecular weight and chemical type will reveal distinct and definitive signatures of life. The ability of tandem mass spectrometry in the ion trap to selectively isolate a high molecular weight com-pound from the other species present in the ion trap, excite the compound and cause it to dissociate, and analyze its fragmentation pattern provides even more information on chemical structure.Advanced GC col-umns allow enantiomeric separation of chiral com-pounds of astrobiological interest such as amino acids – yet another tool to search for biosignatures.

Analog Studies Demonstrate Approach: With the inclusion of ocean worlds as an emerging target for NASA, the mass spectrometer team at GSFC in col-laboration with astrobiology colleagues has initiated a study of biosignature detection in various terrestrial analog environments, such as coastal upwelling and ocean gyre center, alkaline springs, and deep-sea hy-drothermal vents using the techniques described. These studies enable a comparison of analytical techniques and protocols and the promising results of these studies will be presented.

Mission Design, Plume Targeting, Multi-wavelength Imaging, and Planetary Protection: The details of the mission design to enable plume targeting in the context of the EMFM will be described by other presenters at this conference. Advanced imaging sys-tems in the IR, visible, and UV enable characterization of plume and source region morphology. The meas-urement techniques described could form the core of a ground-breaking mission to interogate the Enceladus plumes for signs of life and move toward an answer of the fundamental question of the existence of life in other parts of our solar system.

References: [1] Summons, R. E. et al. (2008)

Space Sci. Rev. 135, 135-159. [2] Bishop, J. L. et al. (2013) Icarus 224, 309-325. [3] Siljestrom, S. C. et al. (2014), Astrobiology, 14, 780-797. [4] Freissinet, C. (2015) JGR, 120, 495-514. [5] Brinckerhoff, W. B. Proc. Aerospace Conf IEEE, DOI: 10.1109/AERO.2013.6496942.



A DESCENT PROBE FOR EUROPA AND THE OTHER GALILEAN MOONS OF JUPITER. P. Wurz1, D. Lasi1, N. Thomas1, D. Piazza1, A. Galli1, M. Jutzi1, S. Barabash2, M. Wieser2, W. Hadjas3, and H. Lammer4, Physikalisches Institut, University of Bern, 3012 Bern, Switzerland ([email protected]), 2Swedish Institute of Space Physics, Kiruna, Sweden, 3Paul Scherrer Institut, Villingen, Switzerland, 3Space Research Institute, Austri-an Academy of Sciences, Graz, Austria.

Introduction: We present a study of an impacting

descent probe for Europa (EDP) to increase the science return of spacecraft orbiting or flying-by atmosphere-less planetary bodies of the solar system, such as the Galilean moons of Jupiter. EDP is a carry-on small spacecraft (< 100 kg), to be deployed by the mother spacecraft. After release, the descent probe brings itself onto a collisional trajectory with the targeted planetary body in a simple manner.

Science goals and payload: The foreseen science payload includes instruments for surface imaging (wide-angle camera, WAC), characterization of the neutral exosphere (exosphere mass spectrometer, EMS), magnetic field measurements (magnetometer, MAG), plasma measurements (3D plasma analyzer, 3DPA), and a radiation monitor, near the target body down to very low-altitudes, during the probe short (∼minutes) and fast descent to the surface until impact.

The science goals and the concept of operation are discussed with particular reference to Europa, includ-ing options for after-impact retrieval of very-low alti-tude science data.

Magnetosphere Interactions: in situ measurements of the magnetic fields and currents. Determination of ionospheric plasma populations currents, to identify all external magnetic field soruces from Europa’s induced magnetic field, and search for an intrinsic dipolar field.

Exosphere: EMS mass spectra along the descent trajectory to derive abundance of major species to ad-dress question on the formation, down to trace species for astrobiology and noble gases.

Geochemistry and Geology: Interpretation of the EMS mass spectra and the WAC images to derive mineralogy and geological domains on the surface, in particular areas with low ice abundance.

Astrobiology: Search for biosignatures in the EMS mass spectra, like hydrocarbons or sulfur-bearing mol-ecules.

Engineering Objectives: In addition, there are al-so engineering objectives the EDP will address:

Surface topography: From the WAC images the structure of the surface at length scales of 30 cm will be recorded to support future landings on Europa’s surface.

Radiation environment: The fluxes of penetrating radiation near the surface will be recorded to under-stand the radiation environment for future landers.

Mission Scenario: A sketch of the foreseen mis-sion scenario is given below. The EDP will be released about 24 h before closest approach (CA) from the main spacecraft. The probe will decelerate to enter a colli-sion trajectory with the object. Because EDP moves at a slower speed its prime science time is when the main spacecraft already passed CA, and the main spacecraft can be used to relay the data from the EDP to Earth.

Summary: All in all, we demonstrate how EDP

has the potential to provide a high science return to a mission at a low extra level of complexity, engineering effort, and risk. Given the moderate mass of EDP even two such probes could be carried by the mother space-craft and be used to investigate different surface loca-tions.

This study builds upon earlier studies for a Callisto Descent Probe (CDP) for the former Europa-Jupiter System Mission (EJSM) of ESA and NASA [1,2], and extends them with a detailed assessment of a descent probe designed to be an additional science payload for the NASA Europa Multiple Flyby Mission.

References: [1] Wurz, P., N. Thomas, D. Piazza, M. Jutzi, W.

Benz, S. Barabash, M. Wieser, W. Baumjohann, W. Magnes, H. Lammer, K.H. Glaßmeier, U. Auster, and L. Gurvits, The Callisto Descent Probe, European Planetary Science Congress, (2009) Vol. 4, EPSC2009-375-2, 2009

[2] Wurz, P., S. Barabash, N. Thomas, J. Fischer, D. Piazza, M. Jutzi, W. Benz, M. Wieser, W. Baumjo-hann, W. Magnes, H. Lammer, K.H. Glaßmeier, U. Auster, S. Pogrebenko, L. Gurvits, and G. Managadze, The Callisto Descent Probe, 9th International Plane-tary Probe Workshop (IPPW-9), Toulouse, France, 16th–22nd June 2012



ESA’s CLEO/P study : 3 potential contributions to NASA’s Multi-flyby Europa mission. T. Voirin1, J. Lar-ranaga2, J. Romstedt1, C.P. Escoubet1, R. Biesbroek1, D. Rebuffat1 S. Vijendran1 1 ESA-ESTEC ([email protected]), 2AURORA B.V. for ESA/ESTEC ([email protected]).

Following an ESA-NASA bilateral agreement in

2014, a mutual interest has been expressed by both Agencies for studying a potential contribution of Eu-rope, as a junior partner, to NASA's Europa Multiple Flybys mission, formerly known as Clipper. Such a contribution would be part of ESA’s Science Program (Cosmic Vision) and would consist of a piggyback spacecraft carried by Clipper during interplanetary cruise and released by Clipper in the Jupiter system. It would provide top-level science complementary to ESA’s JUICE and NASA’s Clipper science objectives.

A key requirement from NASA & JPL was that the

ESA spacecraft should not exceed 250 kg. Following a preliminary brainstorming by ESA, including iterations between system and science support teams, three pos-sible piggyback concepts for such a contribution within the mass constraint were identified for further study, in agreement with NASA and JPL teams, namely (i) a spacecraft performing several flybys of Io (e.g. Io ac-tive volcanism investigation) ; (ii) a spacecraft per-forming several flybys of Europa (e.g. for Europa plumes in-situ assessment) and (iii) a Europa penetra-tor concept, with high velocity impact on Europa and subsurface investigations (including a habitability package). Spacecraft concepts such as a Europa orbiter and a Europa lander, although scientifically meaningful, were not considered feasible within the allocated mass envelope of 250 kg and as a consequence were not studied further. These three pigyyback concepts were subject to a ded-icated ESA-internal “Phase 0” system study, carried out in ESA’s Concurrent Design Facility (CDF) in 2015. This study was called CLEO/P: Clipper ESA Orbiter or Penetrator. The CDF study concluded that CLEO/P concepts would be technically feasible, and with respect to the related schedule would also meet programmatic contraints.

This paper will present an overview of the CLEO/P study outcomes in terms of mission concepts and ESA piggyback spacecraft designs.

The CLEO/I or /E spacecraft configuration deployed

(left) and attached to Clipper (right)

Left : the CLEO/P penetrator penetrating the ice ;

Right : the CLEO/P spacecraft, including Penetrator Delivery System and the penetrator (courtesy of Air-

bus Defence & Space UK)



GLOBAL AERIAL EXPLORATION OF OUR SISTER WORLD WITH THE VENUS ATMOSPHERIC MANEUVERABLE PLATFORM (VAMP): MISSION SCIENCE OBJECTIVES AND POTENTIAL INSTRUMENTATION. K. H. Baines1, S. S. Limaye 1, G. Lee2, and B. Sen2, 1Space Science and Engineering Center, University of Wisconsin-Madison, Madison, WI, USA ([email protected]), 2 Northrop Grumman Aerospace Systems, Redondo Beach, CA, USA.

Introduction: VAMP, the Venus Atmospheric

Maneuverable Platform, under development by Northrop Grumman, is a versatile twin-engine buoyant aircraft capable of sustained (> months) exploration of Venus. Utilizing both dynamic and buoyant lift, the flying-wing-shaped aerial rover is capable of exploring a wide range of altitudes from its 50-km free-floating “safe-haven” level to over 65 km in altitude. Its solar-powered twin electric engines not only provide power for vertical ascents, but also the power for unprece-dented mobility, enabling the aircraft to cruise up to ~ 30 knots airspeed, and thus allowing pole-ward/equatorward aerial excursions extending over 1400 km (over 12 degrees of latitude) per terrestrial day. Over 4-5 days, the planet’s ~180 knot zonal wind enables the craft to circle the planet exploring all longitudes and times-of-day.

Fig.1 : The VAMP hybrid aerial rover exploring the skies of Venus, powered by twin solar-powered

motors As currently envisioned, VAMP provides unprece-dented large amounts of payload mass, power, and volume for an in-situ Venus explorer. While still under assessment, it is clear that VAMP will provide more than 20 kg for science instrumentation with electrical power exceeding several kilowatts during daylight hours and perhaps a kilowatt during nighttime condi-tions. The relatively large size of the aircraft – with its wings spanning more than 15 meters – provides oppor-tunities for instrumentation requiring relatively large volumes and/or space for an array of apertures (e.g., various forms of radar or electromagnetic detectors). Atmospheric Science with VAMP: Objectives and Techniques: VAMP thus provides an unusually versatile platform for the in-situ aerial exploration of Venus, conducting an array of novel measurements that promise to provide crucial insights into virtually all aspects of Venus atmospheric science, including (1) the planet’s origin and evolution, (2) its active and

varying chemistry, driven by latitudinally, time-of-day, and vertically varying photochemical/thermodynamical processes, and (3) its global circulation, dynamics, and meteorology. Via mass spectrometry (MS), new in-sights into the origin and evolution of Venus can be provided through accurate measurements of the D/H ratio and the noble gases and their isotopes over both altitude and time-of-day, to correct for fractionation effects. Via tunable laser spectrometry (TLS), the iso-topes of other light elements (e.g., nitrogen, carbon, and oxygen) can be measured as well, providing addi-tional insights into Venus’ origin and evolution. VAMP provides in-situ sampling of key reactive gas species such as H2O, CO, OCS, and SO2 , and can do so regularly over altitude, latitude, and time-of-day via the MS, TLS and/or a near-infrared spectrometer operating in the 1-2.7-µm range. Using a nephelome-ter that includes a high-resolution optical microscope for aerosol imaging, the size, shape, and chemical composition of aerosols can be accurately determined, which, together with the reactive gas abundance data, promises to provide additional valuable insights into chemical cycles within Venus’ dynamic clouds. VAMP’s mobility promises to be extremely effec-tive at measuring crucial aspects of the planet’s dy-namics and circulation, including local meteorological effects. The aerial rover’s ability to travel across nearly the entire globe over several weeks (likely limited by diminishing solar power poleward of ~ 70o latitude) enables it to measure key aspects of any Hadley cells as well as the characteristics of planetary and gravity waves over nearly the entire planet. Using Doppler radar, it can measure its ground speed both day and night and thus accurately measure both the meridional and zonal winds from 50 to ~ 65 km altitude. Its pres-sure (P) and temperature (T) sensors will continually sample the atmosphere. Vertical traverses (typically both ascents during the day, and descents from high altitudes during the night), will allow the temperature gradient (dT/dz) to be assessed, from which the stabil-ity of the atmosphere, as a function of altitude, can be determined. A key parameter for understanding the planet’s thermal structure and stability at lower alti-tudes is the vertical variability of the N2 abundance. While commonly considered to be constant at 3.5%, previous probes strongly suggest some 40% variability from ~ 22 km to ~52 km altitude. VAMP is well-suited to repeatedly measure N2 and its vertical variability above 50 km as observed over day/night conditions



and latitude. Any confirmed variability would have strong implications on the planet’s lapse rate, thermal structure, stability, and flux of material, temperature, and momentum from near the surface to the cloud lev-el, potentially providing significant new insights into mechanisms driving the planet’s circulation, including its not-well-understood super-rotation. Within the clouds, the vertical component of the wind can be measured from an on-board vertical wind sensor com-bined with the pressure (P) data, from which, when combined with the dT/dz information, the relative roles of convection and vertical waves (e.g., gravity waves) can be assessed over various terrains as well as lati-tudes and time-of-day. Investigations of vertical dy-namics combined with measurements of lightning from an onboard lightning detector will provide new insights into the role lightning and convective storms play in Venus’s meteorology and chemistry, particularly in the production of lightning-generated species (e.g., NO). Additional information over altitude comes from two other aspects of a likely mission. First, during atmos-pheric entry, VAMP’s low-density design enables it to slow to “observing speed” above ~ 90 km altitude, enabling the aircraft to make in-situ measurements from well above the unexplored UV aerosol layer down to ~ 50 km level. Second, the relatively large payload capability allows the possibility for both drop-sondes and balloon-borne “rise sondes” to be de-ployed, sampling both lower and higher altitudes than the 50-~65 km altitude regularly sampled by VAMP. Surface/Geologic Science with VAMP: Objec-tives and Techniques: Beyond aerial exploration for atmospheric science, VAMP also provides a valuable platform for discovering new insights into the planet’s surface geology and interior. RADAR maps and nighttime near-IR images can be used to characterize the surface topography, surface texture, and crude chemical make-up (e.g., igneous vs basaltic rocks), from which geological insights (e.g., the extent and relative age of surface volcanism) can be made. As well, an array of aural seismic detectors can be de-ployed which listen for the deep rumble of seismic events. As well, a large (multi-meter-wide) electro-magnetic array carried aboard VAMP could possibly sound more than 10 km below the planet’s surface, to map the depth of the lithosphere. Conclusion: VAMP thus provides a particularly versatile aerial platform for the exploration of nearly the entire planet, with particular emphasis on sampling highly diagnostic gases, aerosols, winds, temperatures, pressures and lightning characteristics, as well as for mapping key characteristics of surface geology. As such, it is an ideal platform around which to base an internationally collaborative mission.

.



DAVINCI: DEEP ATMOSPHERE VENUS INVESTIGATION OF NOBLE GASES, CHEMISTRY, AND IMAGING. L. S. Glaze1, J. B. Garvin1, N. M. Johnson1, M. J. Amato1, J. Thompson1, C. Goodloe1, D. Everett1, and the DAVINCI Science Team, 1NASA Goddard Space Flight Center (Code 690, Greenbelt, MD, 20771, [email protected]).

Introduction: DAVINCI is one of five Discovery-

class missions selected by NASA for Phase A studies. Launching in November 2021 and arriving at Venus in June of 2023, DAVINCI would be the first U.S. entry probe to target Venus’ atmosphere in 45 years. DAVINCI is designed to study the chemical and iso-topic composition of Venus’ atmosphere at a level of detail that has not been possible on earlier missions and to image the surface at optical wavelengths and process-relevant scales.

Science: Venus and Earth experienced vastly dif-

ferent evolutionary pathways resulting in unexplained differences in atmospheric composition and dynamics, as well as in geophysical processes of the planetary surfaces and interiors. Understanding when and why the evolutionary pathways of Venus and Earth di-verged is key to understanding how terrestrial planets form and how their atmospheres and surfaces evolve. DAVINCI would provide these missing puzzle pieces needed to understand terrestrial planet formation and

evolution in the solar system and beyond. The mission is tightly focused on answering fundamental questions that have been ranked as high priority by the last two National Research Council (NRC) Planetary Decadal Surveys [1-3] as well as by the Venus Exploration Analysis Group (VEXAG) since the time of its incep-tion in 2005 [4]. For example, DAVINCI will make measurements of the heaviest noble gases, including the first ever measurements of xenon [5]. These defini-tive measurements, which would be made well below the homopause to avoid any ambiguity, are sufficient to answer questions as framed by the NRC Planetary Decadal Survey and VEXAG, without the need to re-peat them in New Frontiers or other future missions.

The three major DAVINCI science objectives are: • Atmospheric origin and evolution: Understand the

origin of the Venus atmosphere, how it has evolved, and how and why it is different from the atmospheres of Earth and Mars.

• Atmospheric composition and surface interaction: Understand the history of water on Venus and the chemical processes at work in the lower atmos-phere.

• Surface properties: Provide insights into tectonic, volcanic, and weathering history of a typical tes-sera terrain.

Mission Design: The DAVINCI probe will make

in situ measurements during its one-hour descent through the Venus atmosphere. The descent sphere itself builds on the successful Pioneer Venus Large Probe design. The descent sphere and payload are pro-tected during intial atmopsheric entry by a solid body aeroshell.

The DAVINCI probe would be delivered to Venus by a carrier/telecommunications spacecraft (built by Lockheed Martin). The spacecraft first encounters Venus four months after launch. This initial flyby ena-bles targeting, when the spacecraft returns to Venus 15 months later, of the probe atmospheric entry location for optimized lighting conditions in the tessera region chosen for descent imaging. The probe is released a few days before the second Venus encounter and the spacecraft communicates directly with the probe throughout coast, entry and descent. The probe em-ploys a two-parachute system to extract the descent sphere from the entry system and to slow descent.



The entire science payload is contained within the pressure and temperature controlled descent sphere. All science data are collected and relayed to the flyby spacecraft during descent. DAVINCI has no require-ment to survive touchdown, however, the descent sphere carries sufficient resources (e.g., power, thermal control) to continue science operations and data relay for ~20 minutes on the surface. After loss of contact with the probe, the spacecraft begins relay of all data back to Earth.

Payload: DAVINCI builds on the tremendous success of the Mars Science Laboratory Sample Anal-ysis at Mars (MSL/SAM) suite carried on the Curiosity rover [6-13], by pairing the Venus Mass Spectrometer (VMS) led by NASA’s Goddard Space Flight Center with the Venus Tunable Laser Spectrometer (VTLS) led by the Jet Propulsion Laboratory. Combined, these two instruments provide the first comprehensive meas-urements of noble and trace gas species, as well as key elemental isotopes.

These two state-of-the art instruments are comple-mented by the Venus Atmospheric Structure Investiga-tion (VASI), which provides measurements of the structure and dynamics of the Venus atmosphere dur-ing entry and descent as context for the chemistry measurements, and enables reconstruction of the de-scent profile.

The Venus Descent Imager (VenDI) provides high-contrast descent imaging of the tessera terrain. Malin Space Science Systems is leveraging experience with the Curiosity Rover’s Mastcam and MARDI descent video imaging systems to develop VenDI.

Conclusions: An atmospheric probe, leveraging proven 21st Century instrument technology, definitive-ly resolves key Venus atmospheric science questions. Imaging of tessera at scales relevant to a lander will resolve radar ambiguities and uncertainties. DAVINCI will meet multiple, high-priority National Academy of Sciences goals, while also serving as a pathfinder for future orbital radar missions and landed missions to the Venus highlands.

References: [1] Crisp, D., et al. (2002) ASP conference Series,

272, Ed. MV Sykes, 5-34. [2] New Frontiers in the Solar System (2003) National Research Council of the National Academies, National Academies Press. [3] Visions and Voyages (2011) National Research Council of the National Academies, National Acade-mies Press. [4] VEXAG (2014) http://www.lpi.usra.edu/vexag/reports/GOI-140625.pdf. [5] Trainer et al. (2016) International-Venus Conference, Oxford. [6] Mahaffy et al. (2015) Science, 347, 412-414. [7] Webster et al. (2015) Sci-ence, 347, 415-417. [8] Atreya et al. (2013) GRL, 40,

5605-5609. [9] Mahaffy et al. (2013) Science, 341, 263-266. [10] Webster et al. (2013) Science, 341, 260-263. [11] Wong et al. (2013) GRL, 40, 6033-6037. [12] Conrad et al. (2014) LPSC XLV, Abstract #2366. [13] Webster et al. (2016) International Venus Conference, Oxford.



Biosignature Explorer for Europa (BEE) Probe –Directly Searching for Life Evidence on Europa. Michael J.

Amato1, P. Spidaliere1, P. Mahaffy1, C. Schiff1, O. Hsu1, T. Hurford1, M. Benha1, W. Brinckerhoff1, J. Garvin1, J.

Downing1, T. Errigo1, D. Glavin1, M. Sarantos2, R. Lorenz3, T. Hoehler4, et al. 1NASA Goddard Space Flight Center

(GSFC), Greenbelt MD. 2 University of Maryland Baltimore County/NASA Goddard Space Flight Center, 3 JHU

Applied Physics Laboratory, 4 NASA Ames Research Center,

Introduction:

Evidence for Europa’s substantial sub crustal water

ocean leaves us with the curcial question of if the

ocean is habitable and if it harbors life.

The tantalizing possibility of hydrothermal activity

below its ice crust shell has placed Europa as one of

the highest priority targets in the search for habitable

environmentsand potentially extant life [NRC, 2011].

The compositional analysis of potential plumes is a

high-value objective. Sporadic eruptive plumes at Eu-

ropa have been observed [Roth et al., 2013], and analy-

sis shows plume activity is likely at lower intensities

The plumes represent an opportunity to uniquely-

probe the chemistry of the subsurface ocean and assess

Europa’s potential to sustain life by looking for bio

signatures. Freshly-ejected ocean material would repre-

sent a relatively unaltered sample of the subsurface

chemistry, as compared to sputtered surface materials

exposed to high energy radiation that will destroy or-

ganic compounds. In addition to the detection of more

pristine organic molecules, the composition of the oth-

er constututnes such as salts in the ocean has important

implications for the source of ocean materials [e.g.,

Brown and Hand, 2013].

The potential changing intensity of the plumes at

Europa calls for a versatile measurements strategy that

can accommodate a wide range of geographical loca-

tions and outgassing intensities. While the NASA Eu-

ropa mission spacecraft is well equipped for Europa

studies, which include plume detection and characteri-

zation, more is needed to fully analyze Europa plumes.

The recently selected instrument suite likely lacks the

ability to achieve the highly desirable and difficult de-

tection of direct biosignatures or life evidence. In addi-

tion, the Clipper mission may not be able to easily

modify its orbital trajectory or altitude to fly through

plumes or remotely study plume events that may be

short lived or highly diffuse. Thus, a smaller Probe

equipped with the focused set of instruments and navi-

gation capabilities is better suited to target detection of

bio signatures and can target denser plumes and lower

altitudes that might be otherwise inaccessible to the

Europa Clipper spacecraft.

The BEE plume probe:

A small plume probe would have more flexibility to

perform the critical science investigations in support of

the goal of exploring Europa plumes for evidence of

past or current life on Europa. Objectives to meet this

goal could include: 1) Characterizing the building

blocks of life within the plumes, 2) investigating plume

source regions to assess them as a biological niche en-

vironment and 3) further assess plume source regions

for future landed missions.

Our team has designed a Biosignature Explorer for

Europa (BEE) Probe concept to ‘taste’ the ocean by in

situ analysis of plume sample for biosignatures, which

provide the most science and most programmatically

robust way to determine if the Europa ocean harbors

life evidence. By flying directly through a plume, the

BEE is able to sample freshly released ocean water and

search for evidence of extant life. BEE does this by

using newly matured collection approaches and mass

spectrometer designs based leveraging heritage ap-

proaches. The search for direct in situ molecular bi-

osignatures is the clearest path toward to definitive

identification of signatures of life as we know it at Eu-

ropa.

The BEE will search for molecular signatures of

life by capturing material soon after it is released from

a subsurface reservoir, and conduct chemical analysis

with experiments optimized for detection of molecular

biosignatures. Plume fly-through with sampling and

molecular analysis is akin to “landerless landing” in an

ocean (or fresh ocean deposit) in the quest for Europa

ocean biosignatures

The BEE fly-through approach may offer many

advantages over static landings. BEE plume sampling

collects intact biomarker material before their inevita-

ble destruction by radiation after release from the

ocean. BEE offers better access to freash material by

targetating plumes or active targets (2-10 km fly

through corridor vs. lander Braking-Descent-Landing

(BDL) uncertainty of at least 75-100km or worse).

BEE is less sensitive to radiation damage and effects

on sensitive instrumentation. BEE has no landing loads

on sensitive bio-molecule sensors. BEE’s broad re-

gional context can be established with simple imaging

systems.

BEE can be more agile and responsive to activity

on Europa when we arrive with the Europa mission,



allowing easier targeting to the “the action”. BEE has

no BDL lander systems and cost, uses less resources,

has less complexity, has fewer mission constraints and

no landing risks that will drive additional costs. BEE

has an advanced NASA Goddard Space Flight Center

led mass spectrometer with a large area collection ap-

proach that leverages past designs while enabling new

direct biosignature science. The sensitive mass spec-

trometer is combined with other separation approaches

for definitive identification of biosignatures. It also

carries the BEE UV plume targeting camera as well as

visible and IR cameras to image the active region with

better resolution than the Europa mother ships instru-

ments.

The BEE team has refined its cadence of prerelease

survey, probe release, refined targeting, sample collec-

tion, analysis and transmit operations. BEE is released

from the mother ship many hours before closest ap-

proach to Europa. Initial targeting is done using plume

data from the Europa mission instrument suite. Refined

targeting on a plume is aided by BEEs unique targeting

camera that senses emissions night or day. The BEE

probe flies thru at very low km altitude and collects

material. The probe images the surface in visible and

infrared at process-diagnostic scales. After exiting the

intense radiation environment, it uses proven mass

spectrometer technology to analyze the material for

biosignatures. The BEE then transmits the data back to

the Europa mission mother spacecraft. The BEE can be

released during a large number of the baselined flybys.

The BEE uses its refined targeting and propulsion sys-

tem to enable targeted access a majority of Europa’s

surface.

The small BEE probe attaches to the Clipper mis-

sion, currently on its NADIR viewing side. The BEE

team has worked with the Europa mission project engi-

neering team to work out initial mechanical, load, elec-

trical, communications and operations details that have

low cost and resources impact on the main mission.

BEE employs a modular mechanical design and a care-

fully designed internal radiation protection vault to

protect sensitive electronics from radiation effects and

is under 250 Kg.

The BEE probe ACS and propulsion system are de-

signed to enable targeting and post sample collection

maneuvers. BEE is three axis stabilized and utilizes

acceleration measurement systems, star sensors and

other packages. The propulsions system is a hybrid

system combining a basic bi-propellant design with a

simple hydrogen driven three axis cold gas system that

is compatible for use just before and during sample

collection.

The BEE’s avionics utilize a selectively redundant

design that leverages multiple NASA Goddard Space

Flight Center (GSFC) systems designed for far from

earth applications. The design has high performance

processor and memory units combined with a number

of interfaces cards. These interfaces include power and

data interfaces, propulsion and actuator interfaces, re-

fined targeting sensor interfaces and redundant X-band

transponder. The BEE’s power system is currently a

heritage primary battery designed with multiple battery

cell strings.

The BEEs thermal system utilizes blanketing and

four thermal zones as well as survival heaters. The bat-

tery system is isolated from the electronics vault to

minimize heating requirements but the propulsion tanks

are thermally linked to the vault. A separate thermal

interface will be linked to the mother spacecraft ther-

mal system during cruise.

The BEE probe is a feasible way to achieve criti-

cal biosignature and life evidence goals with less risk

and lower cost than other options. The BEE team has

shown this approach to be feasible approach to be con-

sidered.

Figure 1 – The BEE probe design and its current loca-

tion on the Europa mission spacecraft.

Acknowledgments: The author would like to

acknowledge NASA Headquarters Planetary Science

Division PSD for follow on study support and the

many team members at NASA GSFC and other institu-

tions involved in the BEE probe work.

References - [1] NRC, 2011, [2] Roth et al., 2013 [3]

Brown and Hand, 2013



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