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Live: SpaceX Dragon docking with ISS

bbc.co.uk

81–90 of 109 posts

Re: Live: SpaceX Dragon docking with ISS

#86
post #81

Earlier quoted context omitted.

That was great. Arm moving now! Edit: CAPTURE CONFIRMED!

Did you hear the part when he said "Looks like we have a dragon by the tail?" I cracked up.

Yes! Goosebumps.. But, I must unfortunately confess.. seeing all that unbranded space on the Dragon had me cynically thinking, how much could they sell that ad space for?

Re: Live: SpaceX Dragon docking with ISS

#88
post #70

This is just awesome. I'm sitting in the middle of the French country side in a building that was built during Galileo's life time with these links up across three monitors: http://www.n2yo.com/?s=38348 mms://a1709.l1856953708.c18569.g.lm.akamaistream.net/D/1709/18569/v0001/reflector:53708 http://www.nasa.gov/multimedia/nasatv/index.html?param=stati... Watching all of this makes me realise just how lucky we are to be…

Watching all of this makes me realise just how lucky we are to be alive at this point in human history.

Indeed. Sexy times!

Captured dragon: http://imgur.com/Vmnzj and http://imgur.com/mQU91

Re: Live: SpaceX Dragon docking with ISS

#89
post #72
post #60

Question: if Dragon is about 200m lower than ISS, and they are moving at the same velocity at one instant, wouldn't that put them in different orbits? Assuming ISS's orbit was perfectly circular, then Dragon would be moving too slow for its lower orbit, and would sink down, to its perihelion when on the opposite side of the earth, and so on, oscillating up and down, in an elliptical orbit with respect to ISS. The onl…

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Re: Live: SpaceX Dragon docking with ISS

#90

Earlier quoted context omitted.

Aren't lower orbits faster? So wouldn't dragon be moving too slowly to maintain it's orbit, not too fast?

Think of energy. The higher orbit has higher energy with respect to the earth -- gravitational, and by virtue of comparing stable orbits, also kinetic. Dragon will "catch up" with the space station by converting some additional chemical energy (propellant) into kinetic energy, moving into and matching the station's orbit (and gaining the additional gravitational potential). (Or, given the small adjustment needed, per…

Lower orbits have higher anglular velocity -- and it is angular velocity that dictates which craft gets ahead on orbit, because we're comparing angular position, not linear one.

For example, geostationary orbit (~36'000km radius) has period of 24h -- i.e., takes whole 24hours to cover all 360 degrees of rotation, having angular speed of 15deg/h, while Hubble's Space Telescope orbit (~560km radius) has period of 96minutes -- i.e., takes just over 1.5h to cover 360 degrees; with angular speed of 240deg/h.

Sure GEO has higher linear velocity and associated kinetic energy, but that's irrelevant.

I guess the Dragon was positioned under the Station so it gains the angular position slowly over time in a natural way.

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