QUESTION:
What exactly became of the second and third stages of the Delta booster for
the Pathfinder launch?

Did the second stage leave Earth orbit? If so, how close will it come to
Mars? How close will the third stage come to Mars?

For those stages that did leave Earth orbit, how far into the future were
their orbits predicted to make sure that they did not collide with either
the Earth or Mars at some later date?

ANSWER from Pieter Kallemeyn on August 27, 1997:
The first stage came down in the Atlantic.  The second stage burned twice,
and after the second burn was completed was in a highly elliptical (173 x
4600 km) orbit about Earth.  Pathfinder and the third stage were sent on an
escape trajectory, with the third stage predicted to fly by at an altitude
of approx. 500,000 km from Mars.

We did not predict the orbit of the boost stage beyond Mars flyby for two
reasons.  One, there was no tracking of the third stage after separation, so
the post-injection orbit knowledge of the boost stage was poor (we did, of
course, track Pathfinder, but the nongravitation forces are different
between the spacecraft and the boost stage).  Furthermore, the Mars flyby
will magnify uncertainties in the initial orbit prediction (chaos theory,
right?), making any prediction after the flyby unreliable for the purposes
of predicting an Earth or Mars impact.

For example, if our post-flyby orbit prediction placed the boost stage on a
direct impact with Earth, the very large uncertainties about that prediction
would still result in our conclusion that the odds of an actual impact were
extremely low.

Pieter Kallemeyn
MPF Navigation Team Chief