Space Forum / Space Flight / November 2003

I have a few dynamical questions, that I was hoping to get some "top
line" answers to:-

Suppose I want to propel a (hypothetical) 300-kg mass orbiter to
rendezvous with the Moon for lunar orbit capture, departing from a
circular LEO orbit of 400-km altitude inclined at 20 degrees to Earth
equator. Would I be right in thinking the Delta V increment would need
acclerate the craft from 7.7 km/s (LEO speed) to 11.3 km/s (Earth
escape)... a near 50% increase in velocity to achieve Earth to Moon
transfer orbit? What would be the fuel requirements (in terms of
additional propellant mass on top of the 300-kg existing orbiter mass)
to achieve such a transfer? How long should the burn time be (assuming
a simple RP-1 type propellant)? Would my hypothetical LEO orbiter need
to pre-adjust its orbital incline from 20 degrees to 28.6 degrees (I
assume to be co-planer with the Moon's 23.5 degree ecliptic + 5.1
degrees incline vs Earth equator) prior to firing the LEO departure
burn?

What would be the transit time (from LEO to lunar orbital capture) and
finally, how much retro firing would be required at the Moon end to
achieve initial orbit capture... assuming a lunar orbit of reasonable
altitde and shape?

In this simplified scenario, would I be o.k. to aim for a single
impulse Hohmann transfer ellipse (with just one departure burn at LEO
and no course corrections!) ensuring that its apogee point will
intersect the lunar orbit? Also if the transit time of the orbiter
from LEO to Moon is "T" hours, would the major axis of the transfer
orbit ellipse need to aim at a point which is (T*0.5) degrees ahead of
the Moon in its orbit (assuming the Moon moves roughly 0.5
degrees/hour along its orbit) so that both my orbiter and the Moon
meet at the same place at the same time?

Sorry for the long post, but I am sure you can appreciate the
complications!
Sincerely,
Abdul Ahad
http://uk.geocities.com/aa_spaceagent/