california institute of technology neocam update joe masiero · national aeronautics and space...

National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology

6/25/2019 COMPETITION SENSITIVE: PRE-DECISION DRAFT: For Planning and Discussion Purposes Only

1PRE-DECISION DRAFT: For Planning and Discussion Purposes Only

NEOCam Update

Joe Masiero(NASA Jet Propulsion Laboratory/California Institute of Technology)

June 2019

March 2019 Pre-Decisional Information – For Planning and Discussion Purposes only

National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Top Goal

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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Top Goal

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NEOs: The Critical Questions• Need to know when impacts could occur and how bad they will be

• When: Comes from finding objects & determining good orbits for them

• How bad: Comes from measuring the impact energy (KE)• Impact energy scales as KE = ½ mass x velocity2• Velocity comes from orbit• Mass = density x volume = density x diameter3• Impact energy depends strongly on diameter

• NEOCam is narrowly focused on answering these questions

NEOCam is a dual-channel imager operating in a single step-and-stare survey mode.

• PI: Amy Mainzer• 50 cm telescope• Two 16 megapixel HgCdTe focal

planes at 4-5.2 & 6-10 μmsimultaneously imaged

• Detectors passively cooled to 40K• Sun-Earth L1 orbit• First proposed 2005• Awarded technology development

funding in 2011 Discovery• Awarded Extended Phase A in 2016• System Requirements Review/Mission

Definition Review passed Feb 2018• Pre-KDP-B review for instrument

passed 11/18 – KDP-B to be scheduled soon

NEOCam

Pre-Decisional Information – For Planning and Discussion Purposes only

PresenterPresentation NotesNEOCam is designed to leverage the NEOWISE experience at finding and characterizing asteroids using a space-based IR telescope.


Asteroid Spectral Energy Distributions Peak in the Infrared

Albedo = 3%

Albedo = 17%

Wavelength (µm)

Flux

(Jy)

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NEOs Are Bright in IR; Stars Less So

Cyan = 3.4 micronsYellow = 12 micronsRed = 22 microns


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NEOCam Is Capable of Approaching 90% for PHAs >140m

From NASA NEO SDT Report (Stokes et al. 2017)• GBO = Ground-based observatory


Cadence & Follow Up

• The NEOCam survey cadence is designed to produce orbits good enough to distinguish an NEO from an MBA

• Cadence optimized for this purpose

• Most objects are detected on many epochs spanning months or years

• In the event there is an object of particular interest, we have the ability to interrupt survey with a Target of Opportunity mode

• Survey cadence consists of a repeating pattern collected on either side of the Sun on ~2 week cycle

National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Mission Objectives

• Find 2/3 of PHAs >140 m in 5 years (goal: 90%) [driving requirement]

• Produce diameters for all detected objects

• Compute albedos where visible data are available

• Compute cumulative chance of impact over next century from PHAs >50 m and comets

• Deliver tracklet data daily; images & extracted source lists every 6 months


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Extended Phase A Technical Progress• Manufacturing flight pathfinder sensor chip assemblies (SCAs)

• Monolithic 2048 x 2048 devices shown to exceed NEOCamrequirements

• Multiple lots grown and processed of both 5 um and 10+ um devices• Extensive radiation & environmental testing performed

• Engineering Unit Camera Enclosure Assembly fabricated and undergoing thermal testing to validate predicted heat loads and temperatures

• Prototyping of NEOCam science data processing pipeline components underway, including

• construction of simulated images • development image differencing proof-of-concept• machine learning-assisted quality assurance• tracklet linking simulations


Detectors• Partnership between Teledyne Imaging Sensors, Univ. of Rochester, JPL• 4 x 1 mosaic of detectors in each channel imaging simultaneously• Long-wavelength HgCdTe material bonded to 20482 HAWAII-2RG readout

• Cutoffs >10 um demonstrated to exceed NEOCam dark current requirements• Mode of dark current driven down to


NEOCam Investigation Team Functions• Investigation Team members ensure mission achieves its Level 1 requirements.

• NEOCam Investigation Team consist of experts in systems engineering, asteroid & comet properties, focal planes, IR instrumentation, & data system architecture.

• Key functions of the Investigation Team:• Develop Level 1 requirements • Calculate & monitor observatory performance against the Level 1

requirements throughout development phases• Develop survey cadence & ensure that it delivers adequate orbits• Develop & deliver survey planning tool used during ops• Contribute expertise on IR focal planes & instrumentation• Ensure data are properly calibrated (fluxes & positions)• Process data & extract moving object candidates• Link candidate moving objects into tracklets & submit to archives• Compute physical properties for objects & deliver to archives

National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Backup


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Mission Objectives• Make significant rapid progress toward finding &

tracking the majority of near-Earth asteroids & comets large enough to cause severe regional damage (diameters >=140m)

• Constrain impact energies to assess risk• Predict the chance of impact from objects capable

of causing severe local damage (diameters 50-140m)

Mission Highlights• 50-cm infrared telescope• Sun-Earth L1 Lagrange point halo

orbit• 2 channels: 4-5.2 um & 6-10 um• FOV: 12.7 sq deg• 3 arcsec pixels• Survey cadence optimized for

detection of potentially hazardous near-Earth asteroids & comets

Approach• JPL will provide the single instrument, including

systems engineering & thermal design• Instrument integration & electronics provided by

Space Dynamics Lab • Telescope (3-mirror anastigmat, beamsplitter, filters,

baffles) provided by L3-SSG• Detectors designed & manufactured by Teledyne

Imaging Systems• Detector characterization performed at U of Rochester• Spacecraft bus & flight system I&T provided by Ball• Survey planning tool & performance prediction by PSI• Image processing & data archiving by IPAC/Caltech

Key Milestones• Discovery Step 1 2006, 2010, 2015• Technology development funding awarded for

detectors in 2011• Discovery Step 2 in 2016• Extended Phase A awarded 2017• SRR/MDR February 2018• Pre-KDP B for instrument November 2018

Near-Earth Object Camera (NEOCam)PI: Amy Mainzer

Telescope entrance aperture

Sunshade & solar panels

Pre-Decisional Information – For Planning and Discussion Purposes only


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Data System & Products• Data products scoped to provide minimum needed to meet planetary

defense mission objectives: • Reliable detections & orbits• Diameters for all objects• Albedos where visible archival data are available• Updated estimate of impact probabilities from asteroids & comets

• Data system architecture based on WISE, 2MASS, Spitzer architecture

• Detections delivered daily to Minor Planet Center (MPC)• Required to provide >90% reliable detections to MPC avoid

contaminating catalog & producing false alarms

• Images, static sky atlas, extracted source databases delivered every 6 months to NASA’s Infrared Science Archive

• Lead: Caltech/IPAC

• Minor planet diameters & albedos delivered to NASA’s Planetary Data System every 6 months

• Lead: Investigation Team

National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Why 140 m and up?

• Two detailed studies (Stokes et al. 2003 & 2017) showed that the bulk of the integrated risk (probability x severity) comes from the largest objects that have not been found and eliminated from further consideration.

• Basically, the big impactors are extremely bad because of D3• This term dominates the risk calculation

• Below 140 m, the risk switches to become evenly split between smaller asteroids and long-period comets

• Small asteroids are far more numerous, but their impacts are less bad • However, their true numbers are poorly known

• Long-period comets are far less numerous, but their impacts are very bad due to high velocities & large sizes

• However, their true numbers are also poorly known

• NEOCam would address the risk from the largest objects (>140 m) and would tell us about the relative numbers of smaller asteroids and long-period comets

• Thus, it would inform whether or not to do any further planetary defense surveys after this one

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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology NEO Albedo Distribution

• There is a population of very dark NEOs (3% albedo), and a population of less dark ones (17% albedo)

• Data from NEOWISE• Recent results from Ryugu and

Bennu confirm very low albedos

Albedo

Num

ber o

f Obj

ects

3% albedo 17% albedo

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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Mission Summary:

NEOCam Is a Planetary Defense Mission

• NEOCam is designed to respond to the objectives of NASA’s Planetary Defense Coordination Office by discovering, tracking, and characterizing NEOs

• NEOCam is optimized for the task of finding and characterizing the risks posed by potentially hazardous objects (PHOs), both as individual objects and as populations

• NEOCam provides critical decision support for stakeholders who must assess the risks of NEO impacts to Earth and must identify potential mitigation strategies

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Orbit: Sun-Earth L1 Lagrange Point

• Close, constant distance from Earth allows full-frame images to be downlinked

• Thermal environment allows passive cooling to 40 K

• Key enabling technology

NEOCam Viewing Zones

NEOWISE Viewing Zone

National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Cadence

NEOCam Update��Joe Masiero�(NASA Jet Propulsion Laboratory/California Institute of Technology)��June 2019Top GoalTop GoalNEOs: The Critical QuestionsNEOCamAsteroid Spectral Energy Distributions Peak in the InfraredNEOs Are Bright in IR; Stars Less SoNEOCam Is Capable of Approaching 90% for PHAs >140m Cadence & Follow UpMission ObjectivesExtended Phase A Technical ProgressDetectorsNEOCam Investigation Team FunctionsBackupSlide Number 15Data System & ProductsWhy 140 m and up?NEO Albedo DistributionMission Summary: �NEOCam Is a Planetary Defense MissionOrbit: Sun-Earth �L1 Lagrange PointCadence

california institute of technology neocam update joe masiero · national aeronautics and space...

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