Author Topic: Researching Soviet moon program-have orbits, help back-computing delta-V please?  (Read 370 times)

Offline Everett

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I'm researching the Soviet manned lunar landing program, and for all the research I've done, I can't figure out the delta-V for the various planned burns (excluding course corrections of course). Since the burns at the moon all involve a payload that isn't constant for a given stage, I can't just plug the isp and mass (which I do have) into the rocket equation to figure out spacecraft delta-V. I do have a detailed list of which orbits the spacecraft would be in, and I'm hoping here that someone would be willing to do the math I don't know how to do to figure out the delta-V to move between them. :)

Anyway, here's the orbits:

-after launch (don't need delta-V for that): 220 km, 51.8 degree inclination parking orbit

-TLI burn; this used it's own stage, and I can use mass and isp to figure out the delta-V here.

-trans-lunar coast was 3.5 days.

Lunar orbit insertion burn, (elliptical orbit); then circularization burn to circular 110 km orbit, then burn lowering the pericynthion to 14 km. (Since the same stage is doing all this, all I really need is the total for these 3 burns put together; I'd assume that would simplify things. Have a separate figure for the pericynthion lowering burn would be would be nice, if it's not too much trouble.)

-Lunar landing from above orbit

-Lunar ascent to above orbit - the delta-V would be the same for both descent and ascent in this case, right?

-TEI burn - since it's back to one spacecraft at this point, I can figure out delta-V via rocket equation myself.
-3.5 day coast, then skip reentry at 11 km/sec over the south pole, slowing to 7.5 km/sec and skipping out to 5,000 km altitude, and reentry and landing on Soviet soil. (Hopefully.)

Hopefully someone who knows orbital mechanics math can help??? :)
« Last Edit: July 22, 2019, 06:02:11 PM by Everett »