Variable Angle-of-Attack Profile Entry Guidance for a Crewed Lifting ...

the full control power of the aerosurfaces for use in transient maneuvers, improving control power margin.
This is significant, as even when α control is used, bank control is the primary means of steering for most
entry vehicles. This improvement in control power margin may be used to either improve transient maneuver
response times or to reduce the mass of the aerosurfaces by imposing more strict deflection limits, allowing
use of a less massive TPS, or by reducing the size of the aerosurfaces.
While lifting body entry without steady-state LBF deflections has been shown to be feasible, small steadystate
deflections may be used judiciously to reduce the range of α profiles that must be accommodated by
the guidance algorithm and mission designers. Small LBF deflections will likely avoid severe aerothermal
conditions on the flaps and may be used to improve entry performance or overall entry system margins.
Steady-state LBF deflections may also be used after the heat pulse in the low hypersonic and supersonic
regimes when aerosurface heating is no longer a concern. This strategy may provide notable performance
improvements.
Acknowledgement
This work was performed under contract from the Sierra Nevada Corporation.
References
1 Stone, H. W. and Piland, W. M., “21st century space transportation system design approach - HL-20 personnel launch
system,” Journal of Spacecraft and Rockets, Vol. 30, No. 5, Sept. 1993, pp. 521–528.
2 Harpold, J. C. and Graves, C. A., “Shuttle Entry Guidance,” Tech. Rep. NASA-TM-79949, NASA, Houston, Texas, Feb.
1979.
3 Gamble, J. D., Cerimele, C. J., Moore, T. E., and Higgins, J., “Atmospheric Guidance Concepts for an Aeroassist Flight
Experiment,” Journal of the Astronautical Sciences, Vol. 36, No. 1/2, Jan. 1988, pp. 45–71.
4 Rea, J. R. and Putnam, Z. R., “A Comparison of Two Orion Skip Entry Guidance Algorithms,” AIAA Guidance,
Navigation, and Control Conference, Hilton Head, SC, Aug. 2007.
5 McNamara, L. W., “Entry Atmospheric Flight Control Authority Impacts on GN&C and Trajectory Performance for
Orion Exploration Flight Test 1,” AIAA Guidance, Navigation, and Control Conference, Minneapolis, Minnesota, Aug. 2012.
6 Vincenty, T., “Direct and Inverse Solutions of Geodesics on the Ellipsoid with Application of Nested Equations,” Survey
Review, Vol. XXII, No. 176, April 1975, pp. 88–93.
7 Justus, C. G. and Leslie, F. W., “The NASA MSFC Earth Global Reference Atmospheric Model—2007 Version,” Tech.
Rep. NASA-TM-2008-215581, NASA, Nov. 2008.
8 Chapman, D. R., “An Approximate Analytical Method for Studying Entry Into Planetary Atmospheres,” Tech. Rep.
R-11, Ames Research Center, 1959.
9 Tauber, M. E. and Sutton, K., “Stagnation-point Radiative Heating Relations for Earth and Mars Entries,” Journal of
Spacecraft and Rockets, Vol. 28, No. 1, June 2003, pp. 40–42.
10 Ware, G. M. and Cruz, C. I., “Aerodynamic Characteristics of the HL-20,” Journal of Spacecraft and Rockets, Vol. 30,
No. 5, Sept. 1993, pp. 529–536.
11 Powell, R. W., “Six-Degree-of-Freedom Guidance and Control-Entry Analysis of the HL-20,” Journal of Spacecraft and
Rockets, Vol. 30, No. 5, Sept. 1993, pp. 537–542.
12 Howard, R. D., Krevor, Z. C., Mosher, T., Scott, K. P., Voss, J. S., Sanchez, M. J., and Curry, J. M., “Dream Chaser
Commercial Crewed Spacecraft Overview,” 17th AIAA International Space Planes and Hypersonic Systems and Technologies
Conference, April 2011.
13 Ehrlich, K. F., “HL-20 Concept: Design Rationale and Approach,” Journal of Spacecraft and Rockets, Vol. 30, No. 5,
Sept. 1993, pp. 573–581.
14 Wurster, K. E. and Stone, H. W., “Aerodynamic Heating Environment Definition/Thermal Protection System Selection
for the HL-20,” Journal of Spacecraft and Rockets, Vol. 30, No. 5, Sept. 1993, pp. 549–557.
15 Lee, D. L., “Constellation Program Human-Systems Integration Requirements,” Tech. Rep. CxP 70024, Nov. 2010.
16 D’Souza, C. D., Crain, T., Clark, F. D., and Getchius, J., “Orion Cislunar Guidance and Navigation,” AIAA Guidance,
Navigation and Control Conference adn Exhibit, Hilton Head, SC, Aug. 2007, pp. 1–21.
17 Gamble, J. D. and Young, J. C., “The Development and Application of Aerodynamic Uncertianties in the Design of
the Entry Trajectory and Flight Control System of the Space Shuttle Orbiter,” 9th AIAA Atmospheric Flight Mechanics
Conference, NASA Johnson Space Center, San Diego, CA, June 2003, pp. 1–14.
18 Vanderplaats, G. N., Numerical Optimization Techniques for Engineering Design, Vanderplaats Research and Development,
Inc., 2005.
19 Brent, R. P., Algorithms for Minimization without Derivatives, Prentice-Hall, 1972.
20 Powell, R. W. and Cruz, C. I., “Guidance and Control Analysis of the Entry of a Lifting Body Personnel Launch Vehicle,”
29th AIAA Aerospace Sciences Meeting, Reno, NV, Jan. 1991.
21 Bairstow, S. H. and Barton, G. H., “Orion Reentry Guidance with Extended Range Capability Using PredGuid,” AIAA
Guidance, Navigation, and Control Conference, Hilton Head, South Carolina, Aug. 2007, pp. 1–17.
18 of 19
American Institute of Aeronautics and Astronautics