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Are retrograde orbits bad in real life too?


nascarlaser1

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In both RL and KSP, the planet rotates. The Earth rotates at over 1000 mph, and this gives spacecraft heading to equatorial orbit a boost, hence heading east. If you try getting into orbit by going west, you're fighting the Earth's rotation and this means you need slightly more delta-V to achieve orbit. 

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If you hit something going the opposite direction, then there’s twice orbital velocity wrecking things. 

One of the more effective ways to cripple modern communications would be to release a cloud of sand or ball bearings in a retrograde orbit at geostationary height, kicking off the Kessler Syndrome. 

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56 minutes ago, StrandedonEarth said:

If you hit something going the opposite direction, then there’s twice orbital velocity wrecking things. 

One of the more effective ways to cripple modern communications would be to release a cloud of sand or ball bearings in a retrograde orbit at geostationary height, kicking off the Kessler Syndrome. 

Although, realistically, any orbital speed collision will wreck you.

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1 hour ago, sevenperforce said:

Although, realistically, any orbital speed collision will wreck you.

Though you'll get more chances for collisions going retrograde. When you're on the freeway you pass more cars going the opposite way than the direction you're going (assuming similar traffic both ways and you're not going like twice the speed limit).

As to the original question, Kerbin is 600km in radius and rotates once in 6 hours. That means the KSC is rotating around Kerbin at 1200*pi or about 3768km in 6 hours or 628km/h or about 174m/s.

So if you launch EAST you will save 174 m/s from if Kerbin wasn't rotating. But if you launch WEST you lose 174*2 or 348 m/s from a launch the "correct" direction. This is just about a 10% addition to your typical 3500m/s to LKO launch. So it's significant enough to require thought put into it, but not significant enough to totally avoid if you have a good reason (say, the asteroid you're about to capture is passing retrograde).

Now, Kerbin spins faster than Earth and is smaller, and we humans never launch from the equator and frequently divert our launch angle significantly from "directly east" so the savings are not just different, but variable and I can't be bothered to do the calculations.

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56 minutes ago, 5thHorseman said:

When you're on the freeway you pass more cars going the opposite way than the direction you're going (assuming similar traffic both ways and you're not going like twice the speed limit). 

Even if you are going twice the speed limit, given your first criteria (similar traffic), you'll still pass more cars in the opposite direction.    I think the only 'scenario' where the difference between oncoming and .... not sure what the word is for traffic in the same direction..... would be about zero, would be where your speed would be fast enough to make the difference in the two traffics' velocities a tiny tiny negligible fraction of your speed.    So basically, you have access to your own lane, at light speed or faster, and a road of infinite length. 

 

And really good brakes. 

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Retrograde orbit aren't that bad, you can do just fine, if you are willing pay an extra ten-thousand bucks. They aren't really fuel and cost effective, because of Earth's spin, and since spaceflight is all about maximum efficiency, a retrograde orbit really isn't the best choice.

But if you want an extremely destructive way of de-orbiting space junk, then go for retrograde! You can probably de-orbit some of the junk out there all the way to 0m/s if you have craft heavy enough :sticktongue:

Edited by NSEP
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12 hours ago, StrandedonEarth said:

If you hit something going the opposite direction, then there’s twice orbital velocity wrecking things. 

One of the more effective ways to cripple modern communications would be to release a cloud of sand or ball bearings in a retrograde orbit at geostationary height, kicking off the Kessler Syndrome. 

I was going to write this^

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16 hours ago, StrandedonEarth said:

If you hit something going the opposite direction, then there’s twice orbital velocity wrecking things. 

One of the more effective ways to cripple modern communications would be to release a cloud of sand or ball bearings in a retrograde orbit at geostationary height, kicking off the Kessler Syndrome. 

Note that this will only quickly destroy geostationary satellites and threaten other geosynchronous satellites (with 24 hour orbits).  It also doesn't really follow the Kessler syndrome in that parts of one bird are unlikely to damage the next.  The Kessler syndrome seems a bit far fetched in itself: things that are in congested space won't stay in space long without additional thrusts (and smaller pieces fall out of orbit faster) while things at much higher orbits are rare and operate in vast open areas.

The real tragedy of such an attack would be that while the debris from each bird wouldn't put any other bird out of commission, it would also remain wherever the original satellite was effectively rendering that "zone" inhabitable.

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