uranus exploration challenges€¦ · uranus trajectory options • bi-propellant (chemical)...

Uranus Exploration Challenges

Steve Matousek

Workshop on the Study of Icy Giant Planet (2014)

July 30, 2014 (c) 2014 California Institute of Technology. Government sponsorship acknowledged. JPL URS clearance CL#14-3608 1

Outline

• Uranus System Summary • Challenges • Overview of Architectures • How Architectures Meet Challenges • Summary


A Brief History


1986

1781

2010 2011

2008

Higher Maturity Uranus Studies

2015?

202X?

Uranus System Summary


Uranus System Summary (2)


Challenges Challenge Possible Solution

1) Large distance

a) Long flight time Large launch vehicle, Solar Electric Propulsion

b) Large solar distance Radioisotope power (not discussed)

c) Large Earth distance Ka band and/or Optical comm (not discussed)

2) Measurement time Aerocapture to achieve orbit

3) Uranus system

a) Extended atm Orbit farther out

b) Rings Close orbit to avoid rings?

c) Tilted pole Arrival date, propulsion to change orbit inclination

4) Budget Novel flyby, orbiter, probe, and nanosat architectures


Notional Net Spacecraft Delivered Mass

Launch Vehicle Flyby Mission Orbiter Mission

Atlas V 401 800 400

Atlas V 551 2000 1000

Launch Vehicle Flyby Mission Orbiter Mission

Atlas V 401 1000 600

Atlas V 551 2500 1500

Chemical Trajectories (Estimate)

SEP Trajectories (Estimate)

These are rough estimates used for large trade space exploration


Uranus Trajectory Options • Bi-propellant (chemical) trajectories to Uranus are possible • Chemical trajectories require Jupiter or Saturn gravity assist

in order to deliver useable mass to Uranus • Chemical trajectories are typically 13 years flight time or

greater • Numerous families of Solar Electric Propulsion (SEP)

trajectories to Uranus exist • SEP provides 10 year flight times, with potential for 8 or 9

year flight times with Jupiter or Saturn gravity assist • Aerocapture potentially enables larger mass into orbit • Aerocapture requires thermal protection system and

deployments July 30, 2014 (c) 2014 California Institute of Technology. Government sponsorship acknowledged. JPL URS clearance CL#14-3608 8

SEP Example: EEJU

Chemical capture in Uranus orbit

• 1485 kg net mass • 504 kg Xe • 8.66 km/s V∞


SEP Example: Venus-Earth

• 1549 kg net mass (aero.) • 1396 kg net mass (chem.) • 505 kg Xe, 9.44 km/s V∞

Zero-rev to Venus One-rev to Venus

• 1972 kg net mass (aero.) • 1209 kg net mass (chem.) • 688 kg Xe, 11.47 km/s V∞


Easier to Get Into Equatorial Plane ~ 2028 Arrival


• A: Minimum Cost Flyby

Flybys

• B: Flyby w/3 Probes • C: Flyby + Nanosats

Flyby w/Elements

• D: Orbiter with instruments • E: Probiter

Orbiter

• F: Fully Instrumented Orbiter w/Probe • G: Dual Orbiters w/Probe • H: Fully Instrumented Orbiter w/Probe & Nanosats

Orbiter w/Elements

Architecture Concepts


Architectures – A Bit More Detail Architecture Description

A: Min Cost Flyby Limited # of inst, +/- 6 mon planet obs, +/- 1 mon detailed planet and rings, +/- weeks to days for moons and detailed atm

B: Flyby w/3 Probes Flyby S/C with limited # of inst deploys 3 probes, then relays back probe data to Earth

C: Flyby + Nanosats Flyby S/C deploys many nanosats

D: Orbiter with instruments Orbiter with limited instruments. Could also carry nanosats to deploy from orbit.

E: Probiter Orbiter with instruments. Then, deorbits and becomes a probe.

F: Fully Instrumented Orbiter w/Probe

Orbit with full set of instruments. Deploy probe before orbit insertion (easier), or after entering orbit (harder)

G: Dual Orbiters w/Probe Two orbiters, linked or not, one or both carry probes. Payload optimized for orbits (one polar, one equatorial for example)

H: Fully Instrumented Orbiter w/Probe & Nanosats

Large orbiter with probe, much like Decadal Survey probe. Add many nanosats that can go to risky areas and/or give simultaneous measurement by relaying back to orbiter


Meeting Challenges Summary (Subjective ratings)

Architecture/Challenge Ext Atm Rings Tilted

Pole Budget

A: Min Cost Flyby Likely Unlikely

B: Flyby w/3 Probes Possible

C: Flyby + Nanosats

D: Orbiter with instruments

E: Probiter

F: Fully Instrumented Orbiter w/Probe

G: Dual Orbiters w/Probe

H: Fully Instrumented Orbiter w/Probe & Nanosats


Meeting Challenges Summary (2) Architecture Comments

A: Min Cost Flyby Arrival geometry fixed, can target to miss rings

B: Flyby w/3 Probes Probe entry constrained due to arrival geometry

C: Flyby + Nanosats Nanosats can add simultaneous measurements

D: Orbiter with instruments Might be able to avoid rings by going close

E: Probiter Hard to avoid the rings on way to atmosphere

F: Fully Instrumented Orbiter w/Probe Might be able to avoid rings, high $ cost

G: Dual Orbiters w/Probe Easier to get best geometry, high $ cost

H: Fully Instrumented Orbiter w/Probe & Nanosats Most flexibility, high $ cost


Summary • Hard to meet all constraints of inclination, avoid rings,

probe atmosphere, and flyby large moons • Lower cost architectures exist, but they cannot meet all

desires • Continue to invest in key technologies

– Solar Electric Propulsion – Radioisotope power sources – Low power electronics – Aerocapture – Nanosats

• Need studies to look at full extent of architectures


uranus exploration challenges€¦ · uranus trajectory options • bi-propellant (chemical)...

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