NEAR flyby of Earth

RJ@RMATSC.RIEM.COM
Wed, 24 Dec 1997 14:29:56 -0800

Seesat'ers,
	On Jan 23 the NEAR spacecraft will make a close flyby of earth.
Hyperbolic elements have been published at the NEAR web site.
http://sd-www.jhuapl.edu/NEAR/NewMissionDesign/index.html
The Excel version has slightly more information.

Initial JD    Final JD      a (AU)       e          i (deg)  W (deg) w (deg)
2450835.31069 2450838.31069 -8494.702 km 1.81342333 107.9725 88.2548 145.1235
(Periapsis Alt. = 531.6487 km)
This vector is only for the three day period surrounding closest
approach and closest approach is halfway between the two dates.
It will probably change as NEAR nears.

Obviously you can't plug these elements into your regular elliptical-
only orbit propagator.  Here is a state vector suitable for use with
SKYSAT.

NEAR
1 XYZ KM 98023.31069000     1045.94167    -5703.19474     3758.28951
2                         -3.445236000   -7.183138000   -9.941380000

This required quite a bit of hand calculation and I'm a little worried
that it might be very wrong.  If this vector is good, NEAR will 
approach from the direction of M1, pass over Baghdad in daylight and
leave towards the south celestial pole.  It will be visible to observers
in the US just before closest approach.  Assuming a standard magnitude
of 5.5, it should reach magnitude 11 for most of the US, favoring the
West coast.  As luck would have it, I'll be in Florida!

If someone has better information regarding the approach, I'd like to
verify these results.

			Randy John
			members.aol.com/skysatrj