Maneuver strategy for Near's rendezvous with 433 EROS I

On 17 February, 1996, a Delta-2 rocket placed NASA's Near-Earth Asteroid Re ndezvous (NEAR) spacecraft into a 2-year Delta VEGA trajectory that will re ndezvous with the large near-Earth asteroid, 433 Eros in early January 1999 . This paper discusses the strategy for performing NEAR's two large determi nistic Delta Vs, the Deep Space Maneuver (DSM; 269 m/s) 4 months after aphe lion of the initial 2-year orbit and the rendezvous (RND; total 971 m/s) wi th Eros. The DSM was performed flawlessly on 3 July, 1997, 6 days after NEA R's flyby of the main-belt asteroid 253 Mathilde. But NEAR could have still gone into orbit about Eros even if there had been a delay of 8 weeks in pe rforming the DSM. The RND maneuver will be much more time-critical than the DSM. The rendezvous will be split into four burns of decreasing size, the error for each of which will be successively decreased. The design can acco mmodate one-day and two-day delays. After that, NEAR will fly past Eros, ne cessitating longer delays and higher Delta V costs to orbit the asteroid. A strategy is shown that will allow the full Eros orbital phase to be perfor med with delays as long as 40 days in performing the first large rendezvous burn. If in the unlikely event the delay is even longer, NEAR could be aim ed to swing by the Earth in January 2003, and from there it could encounter 4 Vesta and other interesting objects. (C) 1997 International Astronautica l Federation. Published by Elsevier Science Ltd. All rights reserved.