[ExI] Lucy mission to Jupiter Trojan asteroids

spike at rainier66.com spike at rainier66.com
Tue Sep 21 16:02:28 UTC 2021

-----Original Message-----
From: extropy-chat <extropy-chat-bounces at lists.extropy.org> On Behalf Of
BillK via extropy-chat

>...An animation is here:  <https://whereislucy.space>

>...Looks like the sort of thing Spike would design after a few glasses of
sherry!   :)


Never met the girl, BillK.

Those loopy mass-assist orbits using available momentum all make perfect
sense if you have plenty of time.  There isn't much massive stuff out there,
so it does take some patience, which means you need long-lived propellant
(which we have (but it compromises specific thrust (to some extent
(fortunately not severely (hydrazine and nitric acid combination is the most

The asteroids are too small to help all that much in raising perigee, so we
get our first visit out there in 2027 and about every 6 years after that.

Fun aside: one of the early exercises we space geeks did back in 1989-90-ish
was to make a catalog of space objects massive enough to do gravity assist,
then have a kind of brute-force algorithm run over night on our razzle
dazzle new Mac-Praise-the-Woz-Intosh SE (!!running at an astonishing 8
miiiiilllllion (!!) clock cycles per second!) to try combinations chosen at
random, saving the ones which used the least propellant delta V, calculate
total time to desired orbit, keep the best combinations.  Oh we thought we
were soooo smart: we had created a program which could outdo the aged
carbon-based orbit mechanics, so smart were we.  No PhD, not even a Masters,
just a personal computer running overnight, total equipment cost less than a
typical 5 yr old car used at the time.  We had created artificial
intelligence, were so damn smart.  I begged myself for my own autograph.  I
gave me one.  I still have it in my collection of treasured autographs.

When indulging in self-delusion, it helps to not know how dumb one really


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