We’re rewarding the question askers & reputations are being recalculated! Read more.

# Tag Info

## Hot answers tagged rendezvous

58

They are burns, with the direction of the arrow roughly indicating the direction of thrust. Ascent Earth orbit insertion Trans-lunar injection Midcourse correction Lunar orbit insertion Burn to drop out of lunar orbit for landing (LM) Ascent from lunar surface (LM) Lunar orbit insertion (LM) Trans-Earth injection Midcourse correction Whew! Found a ...

19

Lower orbits are faster, higher is slower, so by adjusting orbit altitude you can get an orbit that gains or lags until you are in position do execute a Hohmann transfer. The orbit period is around two hours and the velocities involved around a mile a second so 1000 miles does not have to take that long to close up. Especially if you get both craft change ...

16

There were specific procedures for an abort at any time during the powered descent and after landing. The abort case at the planned time of landing (about 12 minutes after PDI) is covered in this chart: It is from the LM Rendezvous Procedures - G Mission PDF page 78. It's a bit crowded, but it shows the relative profile between CSM and LM, centered on the ...

16

Gemini 4 was the first unsuccessful try of a rendezvous. They sought at that times it should be possible to rendezvous from a short distance by simply thrusting towards the docking object. They had to learn it the hard way that this strategy works only on very, very short distances and in a short time. The circumference of a low Earth circular orbit with a ...

14

The long comment chain below this answer highlights the mis-conception that NASA astronauts as a whole did not understand the orbital mechanics of docking. As this comment points out, the mechanics was well understood at the time, and at least one astronaut had written a thesis on the topic a few years earlier: ... Aldrins thesis about orbital ...

9

First, the Gemini IV maneuver was station-keeping, not rendezvous. Since the target was the just-separated upper stage, the two spacecraft were already rendezvoused, and point-and-burn would have worked if they'd done it properly. According to the Gemini IV mission report, the main causes of station-keeping failure were a mix of procedural mistakes and ...

6

They didn't have two functioning control rooms, so swapped off using the control room for the vehicle that was most active at the time, and used the distributed Mercury-style control for the less active vehicle, swapping back as required. The men in John Hodge's Flight Control Division found it "a hell of a great challenge and to a man they wanted to ...

6

I can't find anything on this online. It would seem to be a useful technique as it would lower the delta-v for the vehicle that lifts the payload from the ground to the rendezvous point relative to fully making orbit. (NOTE: Yes, you'd have to get extra fuel to the tug to perform this manoeuver but that's potentially a smaller problem.) This is the opposite ...

6

The upper stage of the Apollo lunar landing module ("LM") is itself a complete rocket ship, with an engine, propellant tanks, small thrusters to steer with, a guidance computer, and all the other requirements. With the moon's low gravity, it's possible to reach orbit with such a small (~4.5 metric ton) ship, especially as it only needs to operate ...

5

Since you are specifically asking for a reference, I'll refer you to the Appendices in History of Space Shuttle Rendezvous, where these topics are covered in some detail. Appendix G describes the relative frame used in the diagram. Appendix H describes the burn nomenclature (the squares in the picture are burns, and this appendix decodes their names). For ...

3

The launch window for LM might have been about 15 to 30 minutes every two hours, is that right? Not necessarily. Assuming the lunar module could sustain the astronauts for the needed time, the lunar and command service modules could have performed orbit phasing to rendezvous with each other with either the LM or CSM performing the orbital adjustments to ...

3

Let my preface my answer with a quote from Wally Schirra after Gemini 6A: "Somebody said ... when you come to within three miles (5 km), you've rendezvoused. If anybody thinks they've pulled a rendezvous off at three miles (5 km), have fun! This is when we started doing our work. I don't think rendezvous is over until you are stopped – completely stopped – ...

2

[ This is going to be a draft answer as I learn more and get more time to fill it out and edit with symbolic math -- right now its going to be super rough and this answer will evolve a lot over time ] Basic Simplified Problem The generic problem is to take a spacecraft from a set of initial conditions $\vec{r}(0), \vec{v}(0), m(0)$ to a set of terminal ...

1

note: The following two questions are related, may possibly have some helpful information, but both remain unanswered: Did DSCOVR travel “along the stable manifold of it's future SE L1 Halo orbit” to get there? Can Lissajous orbits have stable/unstable manifolds? If a spacecraft was in an EM-L2 halo/lissajous orbit, and another craft would was going to ...

Only top voted, non community-wiki answers of a minimum length are eligible