Aerocapture

From Wikipedia, the free encyclopedia
Jump to: navigation, search
The five steps of an aerocapture

Aerocapture is a technique used to reduce velocity of a spacecraft, arriving at a celestial body with a hyperbolic trajectory, in order to bring it in an orbit with an eccentricity of less than 1.[1] It uses the drag created by the atmosphere of the celestial body to decelerate. Only one pass in the atmosphere is required by this technique, in contrast with aerobraking. However, this approach requires significant thermal protection and precision closed-loop guidance during the maneuver. This level of control authority requires either the production of significant lift, or relatively large attitude control thrusters.

In practice[edit]

Aerocapture has not yet been tried on a planetary mission, but the re-entry skip by Zond 6 and Zond 7 upon lunar return were aerocapture maneuvers, since they turned a hyperbolic orbit into an elliptical orbit. On these missions, since there was no attempt to raise the perigee after the aerocapture, the resulting orbit still intersected the atmosphere, and re-entry occurred at the next perigee.

Aerocapture was originally planned for the Mars Odyssey orbiter,[2] but later changed to aerobraking for reasons of cost and commonality with other missions.[3]

Aerocapture has been proposed and analyzed for arrival at Saturn's moon Titan.[4]

In fiction[edit]

Aerocapture within fiction can be read in Arthur C. Clarke's novel 2010: Odyssey Two, in which two spacecraft (one Russian, one Chinese) both use aerocapture in Jupiter's atmosphere to shed their excess velocity and position themselves for exploring Jupiter's satellites. This can be seen as a special effect in the movie version in which only a Russian spacecraft undergoes aerocapture (in the film incorrectly called aerobraking).

See also[edit]

References[edit]

  1. ^ Cruz, MI (May 8–10, 1979). "The aerocapture vehicle mission design concept". Technical Papers.(A79-34701 14-12). Conference on Advanced Technology for Future Space Systems, Hampton, Va. 1. New York: American Institute of Aeronautics and Astronautics. pp. 195–201. 
  2. ^ "SCIENCE TEAM AND INSTRUMENTS SELECTED FOR MARS SURVEYOR 2001 MISSIONS". 6 November 1997. 
  3. ^ Percy, T.K. and Bright, E. and Torres, A.O. (2005). "Assessing the Relative Risk of Aerocapture Using Probabilistic Risk Assessment". 
  4. ^ Way, D. and Powell, R.W. and Edquist, K. and Masciarelli, J.P. and Starr, B. (2003). "Aerocapture simulation and performance for the Titan Explorer mission". AIAA Paper 495 (1).