So, it was in the news that the Chinese had become the third nation to achieve manual orbital docking of a spacecraft with the International Space Station. I wondered why this would be considered a feat and so I consulted Wikipedia:
http://en.wikipedia.org/wiki/Proximity_operations
Turns out this is not an intuitive operation. The primary reason is due to the effects of accelerating while under the influence of gravity - it raises the craft into a higher orbit which decreases relative velocities. Buzz Aldrin has written a Phd Thesis on the issues of Orbital Mechanics. So, the answers to my (would be) question are probably here:
http://en.wikipedia.org/wiki/Orbital_mechanics
So, what I really want to do in this entry is to work out the simplest cases. If I have a spacecraft just behind (and slightly off to the side of) another in the same orbital plane:
1. What happens when I try to accelerate and then decelerate in order to catch up with it intuitively?
2. What do I have to do (I'll need to fill in the necessary parameters) in order to actually dock with the leading craft?
Hmmm ... side question/observation - Does this mean that a hypothetical vessel orbiting just over the event horizon of a black hole may never be safely docked with? heh.
ReplyDeleteThe answer to the above comment is "no". One can always delay an entire orbital phase by speeding up, gaining orbital height (hence decreasing relative speed), allow the leading vessel to catch up and then dropping down to complete the docking operation.
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