Preliminary considerations for NEAR's low-altitude passes and landing operations at 433 Eros

Abstract

NASA's Near Earth Asteroid Rendezvous O I J E A R) mission is nearing its final goal of rendezvous and orbit about the asteroid 433 Eros starting in December 1998. The asteroid 433 Eros is an irregularly shaped body measuring about 20 km by 40 km overall. The plan. is to

Orbital Motion in Strongly Perturbed Environments

“…The difference of these forms the perturbation gravitational acceleration from a body with mass M p : 3 (2.57) This is a reasonable approximation, although it tacitly assumes that we will not deal with more complex situations where both planetary and solar gravitational perturbations become significant (which would be a 4+ body problem).…”

“…Even though these effects are large, it is possible to characterize them analytically and even use them in the design of close-proximity operations [3]. Such situations have not arisen in classical astrodynamics, where perturbations are generally small and effects take many orbits or days to become significant.…”

“…Related formulae were used to design relatively safe close flybys over the Eros surface [3]. Related formulae were used to design relatively safe close flybys over the Eros surface [3].…”

“…Applying this approach yields the following (p ·r) 2 r 3 = 1 2a 3 (1 − e 2 ) 3/2 1 − (p ·Ĥ) 2 (C.13) (p ·r) r 4 = 1 a 4 (1 − e 2 ) 5/2 e ·p (C.14) (p ·r) 3 r 4 = 3 4a 4 (1 − e 2 ) 5/2 e ·p 1 − (p ·Ĥ) 2 (C. 15) Finally, consider the direct averaging of vectors and their combinations. Although the average is defined with respect to mean anomaly, it is often more convenient to compute averages using the true or eccentric anomaly, using the differential relationships given in Appendix A.…”

“…3 (1 − e 2 ) 3/2 U −ĤĤ (C 17). where the second equation was simplified using the identity U =êê+ê ⊥ê⊥ +ĤĤ.…”