We need to get the space freight off space trucks;
and back on to space trains!
Also, I thought that 56mph (90km/h) was less than escape velocity? Has this truck had its limiter removed? ;)
European space truck the Johannes Kepler successfully docked with the International Space Station this afternoon. The Johannes Kepler approaching the ISS earlier today The Automated Transfer Vehicle (ATV) made initial contact with the orbiting outpost at 15:58 GMT without the need for human intervention, and is now clamped …
The orbit of the ISS is due to it's speed. Basically it is always "falling" towards the Earth because of gravity, but because of it's speed it "misses"; If the Earth was not there, it would be travelling in a straight line, but the gravity of the Earth "bends" it's path around the Earth.
The height of the orbit depends on how fast the ISS is travelling; the faster it is going, the less curved it's path (in other words a larger circle, and hence further from the Earth's surface). You can also think of swinging a brick on the end of a piece of string; the faster you swing the brink, the harder it pulls outward, and this pull is what counter-acts gravity's attempt to make the ISS crash into the ground.
The atmosphere of the Earth does not just stop at a certain point, it keeps on going far far out into space (although the higher you get, the less there is). As the ISS passes through this atmosphere, it suffers from drag, which slows it down. Slowing it down causes it's path to be more bent by gravity, so it's orbit is lower.
The ATV is used to compensate for this by speeding the ISS up. (You can't just push the ISS away from the Earth to raise it's orbit, it would just fall back; you need to speed it up so that it's orbit is less curved.)
The statement says "that the ISS does indeed lose altitude due to skimming the Earth's outer atmosphere, rather than as a result of gravity."
If there was no atmosphere, there would be nothing to slow down the ISS and so it would NOT lose ALTITUDE. Gravity alone (without atmospheric intereference) would maintain the ISS in its orbit and therefore as stated would NOT cause the ISS to lose ALTITUDE.
The statement is correct as written.
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