FEASIBILITY AND MASS-BENEFIT ANALYSIS OF AEROCAPTURE FOR SMALLSAT MISSIONS TO VENUS16th Venus Exploration Analysis Group (VEXAG) MeetingJohns Hopkins University, Applied Physics Lab, Laurel, Maryland, Nov. 6 – 8, 2018

Athul Pradeepkumar Girija | apradee@purdue.eduY. Lu, J. M. Longuski, and S. J. SaikiaSchool of Aeronautics and Astronautics, Purdue University, IN, USA

J. A. CuttsNASA Jet Propulsion Laboratory, California Institute of Technology, CA, USA

VEXAG travel support is gratefully acknowledged

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Aerocapture Control MethodsLift Modulation

Drag Modulation

L

L

D1 D2

MSL-like low L/D aeroshell, HEEET TPS

ADEPT-like system with β2/β1 > 10

β2β1

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1. Dedicated Mission to Venus

Orbit Insertion options

– Propulsive

– Bi-prop. (320 Isp)

– Aerocapture (MSL-like aeroshell)

– Propulsive + Aerobraking

400 x 400 km final orbit

400 x 60,000 kminitial aerobraking orbit

Not to Scale

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2. Rideshare with mission flying to/by Venus

Orbit Insertion options

– Propulsive

– Mono prop. (230 Isp)

– Aerocapture (ADEPT-like aeroshell)

– Propulsive + Aerobraking

400 x 400 km final orbit

400 x 60000 kmInitial aerobraking orbit

Not to Scale

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3. Rideshare with lunar mission 400 x 400 km final orbit

400 x 60000 kmInitial aerobraking orbit

Orbit Insertion options

– Propulsive

– Mono prop.

– SEP

– Aerocapture (ADEPT)

– Propulsive + Aerobraking

Not to Scale

1. Dedicated Mission to Venus: Capture options comparison

Propulsive(400 x 400 km)

Propulsive + Aerobraking(400 x 60,000 km)

Aerocapture(400 x 400 km)

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2.3xpropulsive

2.8xpropulsive

0.7

2. Rideshare with mission flying to/by Venus

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Propulsive(400 x 400 km)

Aerocapture(400 x 400 km)

Propulsive + Aerobraking(400 x 60,000 km)

V∞ = 5 km/s

3.6xpropulsive

4.8xpropulsive

2. Rideshare with mission flying to/by Venus

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2.3x propulsive 2.8x propulsive

3.6xpropulsive

4.8xpropulsive

Propulsive(400 x 400 km)

Aerocapture(400 x 400 km)

Propulsive + Aerobraking(400 x 60,000 km)

V∞ = 10 km/s

3. Rideshare with lunar mission

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2.8x propulsive

4.8xpropulsive

Propulsive(400 x 400 km)

Aerocapture(400 x 400 km)

Propulsive + Aerobraking(400 x 60,000 km)

SEP [6](bound large orbit)

2.3xpropulsive

2.9xpropulsive

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Summary

1. Aerocapture at Venus is feasible using existing low L/D aeroshells, or using drag

modulation systems in development. No new technology is required.

2. Propulsive capture + aerobraking to lower orbit allows most mass delivered, if

the time (several months) for aerobraking is acceptable.

3. Aerocapture offers mass benefit over aerobraking if,

− entry system payload mass fraction > 0.7

− or, for getting into orbit from high V∞ flyby mission

4. If low Venus orbit is desired immediately upon arrival, then compared to

propulsive alone option, aerocapture offers:

– 2.3x mass for dedicated large orbiter

– 3.6x mass for SmallSat ride-along with Venus mission

– 2.3x mass for SmallSat orbiter ride-along from lunar mission

Acknowledgements

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The authors would like to thank Alec Mudek for help with the Earth Venus

interplanetary trajectory data used in this study.

V-BOSS: Venus Bridge Orbiter and Surface System (S. Oleson et al.) study preliminary

report was used for rideshare from lunar mission calculations.

References

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1. M. K. Lockwood et al., “Systems Analysis for a Venus Aerocapture Mission”, NASA/TM-2006-214291, 2006.

2. D. W. Way et al., “MSL: Entry, Descent, and Landing Performance”, IEEE Aerospace Conf., Big Sky, MT, 2006.

3. B. Smith et al., “Nano-ADEPT: An Entry System for Secondary Payloads, IEEE Aerospace Conf., Big Sky, MT, 2015.

4. J. O. Arnold et al., “Arcjet Testing of Woven Carbon Cloth for use on ADEPT”, IEEE Aerospace Conf., Big Sky, MT, 2013.

5. D. Ellerby et al., “HEEET Development Status”, 13th International Planetary Probe Workshop (IPPW), Laurel, MD, 2016.

6. S. Spangelo, D. Dalle, and B. Longmier, “Integrated Vehicle and Trajectory Design of Small Spacecraft with Electric Propulsion for Earth and

Interplanetary Missions”, 29th Annual AIAA/USU Conference on Small Satellites, Logan, UT, 2015 .

7. R. Grimm and M. Gilmore, “VEXAG Update to the NASA Planetary Advisory Committee”, 2018.

8. R. Grimm et al., “Venus Bridge: A SmallSat Program Through the Mid-2020s”, 12th Low-Cost Planetary Missions Conference, Pasadena, CA, 2017.

9. S. Oleson et al., “V-BOSS: Venus Bridge Orbiter and Surface System: Preliminary Report”, 2017.

10. P. Wercinski, “Adaptable, Deployable, Entry and Placement Technology (ADEPT)”, Presentation at NASA Ames Research Center, 2017.

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Backup Slides

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Venus Exploration Domains

Long lived lander

(days)

Aerial platforms

(weeks)

Short lived lander

(hours)

SmallSat

(100 kg)

Comm. relayCubeSat

(5 kg)

Sample return

orbiter

Ascent vehicle

Descent probe

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Approach navigation

Coastphase

Periapsis Raise Maneuver (PRM)

Science Orbit

Too shallowToo steep

Aerocapture

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Lift Modulation: Aerocapture Feasibility Chart

Aerocapture at Venus is feasibleusing existing low L/D aeroshellslike MSL (L/D=0.24) and HEEETTPS material (7000 W/cm2).

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Drag Modulation: Feasibility Chart

Aerocapture at Venus is feasibleusing ADEPT-like dragmodulation systems indevelopment, with a β2 / β1 of~10, and carbon cloth TPS.

The entry corridor for dragmodulation aerocapture issmaller than that for liftmodulation.

Navigation studies will need tobe done to assess if entry flightpath angle errors can bereduced to a level required for itto fit within the drag modulationcorridor.

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Venus Aerocapture Payload Mass Fraction

Rigid lifting aeroshell ADEPT Nano-ADEPT

Payload Mass Frac. 57% * 50% 50%#

* Estimated for using an MSL-like aeroshell for Venus aerocapture# Estimated to be the same as full-scale ADEPT

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Dedicated Launch to Venus – Trajectory Data

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Rideshare with mission flying to/by Venus

Venus Mission Implementation Pathways

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Dedicated Launch

Missions to/flyby Venus

GTO/Lunar

Rideshare Options

Transfer Option

Capture Option

Low-thrust Chemical

Propulsive Propulsive + AB Aerocapture