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RE: How do rockets really get to where they're headed? - Orbital Mechanics
Phaw that's got to be one of the most insanely in-depth posts I've read! Awesome to read though.
I do have a question. On a day-to-day or week-to-week basis how much adjustment of orbit needs to be made by most space craft/ sattelites. Or are they put so precisely into position to start that they're mostly left untouched.
It is hard to get a simple answer on that. Mathematically an orbit is fixed, but in practice it depends on the orbital radius. The lower orbits still encounter runaway atmospheric particles and space dust so the lower the orbit the more adjustment is needed to maintain the orbit.
What I know by heart is that the ISS travels at ~17,500 mph or 7.7 km/s and it falls up to 1.5-2 kilometers per month. so every day it falls up to 100meters. To prevent this, the ISS engines are fired every month with the engines pointed retrograde ( to increase the tangential velocity ). This is enough to speed it up. Due to its sheer mass, the Space Shuttle was used to boost it up with the extra fuel it had before leaving every time, but since then this maintenance is done solely by the Progress Module ( a Russian module - basically a Soyuz, which also acts as the lifeboat of the ISS ).
And the fuel spent is a lot ( here documenting comes in) :
"The ISS requires an average 7,000 kg of propellant each year for altitude maintenance, debris avoidance and attitude control."
and
"Multiple supply vehicles are required to satisfy the ISS's 7,000 kg annual average propellant need.
The Propulsion Module would hold 9808 kg fuel. Progress M holds 1100 kg; Progress M1 holds 1950 kg. ESA ATV holds 4,000 kg."
Wow this is much more than I thought.
Update1:This bandwidth limit is killing me, but I will retry until it works :)
Update2:Since I coudn't post until now I remembered another image which rocked my world:
Finally :)
Hey man! Thanks for the explanation! I knew the ISS orbited low, but I had no idea it required such an active effort to keep it in space!
So the amount of fuel required just to keep afloat is alone enough to prevent the ISS from being self-sufficient... an interesting point. I always thought it was way less dependant than it appears it is!
PS. No wonder you're having issues with bandwidth limit. That image HUGE!
I think the image doesn't reside on the blockchain, that would be overkill. Only the link is written for eternity on the blockchain, and that's a few kb. I am new still and don't have a lot of bandwidth. It will get better after I grow a little more!