Analysis of Temperature-Constrained Ballute Aerocapture for High-Mass Mars Payloads Kristin Gates Medlock (1) Alina A. Alexeenko (2) James M. Longuski (3) (1) Graduate Student, Purdue University (2) Assistant Professor, Purdue University (3) Professor, Purdue University 6 th International Planetary Probe Workshop Atlanta, Georgia June 23-27, 2008 Funded in part by NASA GSRP Fellowship through MSFC MSFC Technical Advisor: Bonnie F. James
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Analysis of Temperature-Constrained Ballute Aerocapture for High-Mass Mars Payloads
Analysis of Temperature-Constrained Ballute Aerocapture for High-Mass Mars Payloads. Kristin Gates Medlock (1) Alina A. Alexeenko (2) James M. Longuski (3). 6 th International Planetary Probe Workshop Atlanta, Georgia June 23-27, 2008. (1) Graduate Student, Purdue University - PowerPoint PPT Presentation
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Analysis of Temperature-Constrained Ballute Aerocapture for High-Mass Mars Payloads
Kristin Gates Medlock(1)
Alina A. Alexeenko(2)
James M. Longuski(3)
(1) Graduate Student, Purdue University(2) Assistant Professor, Purdue University(3) Professor, Purdue University
6th International Planetary Probe WorkshopAtlanta, GeorgiaJune 23-27, 2008
Funded in part by NASA GSRP Fellowship through MSFC
MSFC Technical Advisor: Bonnie F. James
2June 25, 2008 Medlock, Alexeenko, Longuski
Can towed ballutes be used to capture high mass systems at Mars?
High-fidelity aerothermodynamic analysis must be achieved
ballute release
orbiter trajectory
3June 25, 2008 Medlock, Alexeenko, Longuski
Temperature-Constrained Trajectories for Towed Toroidal Ballute Aerocapture at Mars
Aerothermodynamic analysis indicates that CD for Mars is higher than the CD calculated for air at the same Knudsen number (as expected).
Aerothermodynamic analysis (both DSMC and preliminary CFD) predict a lower ballute heat flux than estimated by Sutton-Graves model (34 % lower for the 0.1 ton case and 41% lower for the 1 ton case).
Heating results suggest that ballute-spacecraft systems with larger ballistic coefficients (than predicted by the Sutton-Graves model) are feasible for Mars aerocapture.
Conclusions
15June 25, 2008 Medlock, Alexeenko, Longuski
Back-up Slides
16June 25, 2008 Medlock, Alexeenko, Longuski
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2 DD V AC
DSMC Predictions for CD vs. Kn (Earth)
Mean free path, λ, is a function of altitude
Moss, “DSMC Simulations of Ballute Aerothermodynamics Under Hypersonic Rarefied Conditions”, AIAA 2005-4949.
function of Kn
0
0.5
1
1.5
2
2.5
0.001 0.01 0.1 1 10 100
Knudsen Number = λ/L
Cd
Air (Moss)
17June 25, 2008 Medlock, Alexeenko, Longuski
Stagnation Point Heating Rate0.5 3
s
n
C VQ
R
Larger ballute = lower heating rate at a given altitude