Throwing something overboard from ISS

Leovinus · Jul 17, 2006

I was wondering... If it were possible to throw a 90 mph fastball from the ISS at its current height straight "down" towards the Earth, would it just go into a funky orbit or would you actually be able to get it to snag the atmosphere and burn up? Now instead of straight "down", you threw it at an angle, say 45 degrees into the line of flight from straight down, 45 degrees aft, straight into the line of flight, and straight aft from the line of flight. Which of these angles has the best chance, if any, of throwing the baseball into the atmosphere for burning up? <div class="Discussion_UserSignature"> </div>

Saiph · Jul 17, 2006

straight back, retrograde, will create the largest deviation IIRC. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

Leovinus · Jul 17, 2006

So you're saying that if you throw it straight at the Earth it will come back up before snagging the atmosphere? <div class="Discussion_UserSignature"> </div>

lynchmob98 · Jul 17, 2006

Check out Tony's replies to my question about the spatula (recently loosed from the ISS/Shuttle) ... and/or run the simulations yourself with Tony's awesome software (http://www.orbitsimulator.com/gravity/articles/what.html)!

Saiph · Jul 20, 2006

yep, tony's replies do a good job summing it up. And yes, the object could come back up, and indeed go higher than before (see tony's response). Unless, of course, you throw it hard enough the atmosphere messes with it enough to no longer be free-fall orbital mechanics. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

toothferry · Jul 24, 2006

I suppose throwing the ball up away from the Earth would also cause it to eventually come crashing back down towards ISS. To get the ball to go "down" towards Earth in the long run one would need to throw the ball in the opposite direction of the ISS trajectory, and to get it to go "up" and away from Earth you'd need to throw it in the same direction as ISS's trajectory, increasing its velocity just a bit and causing it to achieve a bit higher orbit. But I bet either way it wouldn't change elevation more than 2 or 3 hundred meters at best. Is any of what I said correct?

Saiph · Jul 24, 2006

well, I haven't run the numbers on how much of a change a human can make, but yeah, you've got the rest down pretty good. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

tony873004 · Jul 25, 2006

It would change by a lot more than a few hundred meters. If you threw it towards Earth at 45 m/s (~100 miles per hour) it would be over 200 meters closer to Earth in less than 5 seconds. Although most of us can't throw this fast, this is about top speed for a major league baseball pitcher. The objects thrown prograde and retrograde would gain or lose 155 kilometers, while the objects thrown towards or away would gain AND lose 39 kilometers. I explained the math in the "spatula" thread. Here's the link to the math: http://orbitsimulator.com/BA/spatula.htm Interesting to note: by throwing directly towards or directly away from the Earth, you do not change the object's semi-major axis. Therefore, you do not change its period. This means that twice per orbit it would come whizzing back at you at 45 meters / second, and in an ideal situation (no external pertabutions, throw is EXACTLY towards or away, Earth is perfectly spherical, etc.) it would hit you on the way back. If you were to distance yourself a few meters from the ISS before making the towards or away throw, the object would appear to orbit the ISS. Here's a screen shot from a simulation showing the trajectories of the ISS, and 4 objects, each thrown ~100 miles per hour, towards, away, prograde, and retrograde. The object thrown towards the Earth spends a quarter of an orbit falling to Earth before its downward motion stops. Then it spends a quarter of an orbit rising to its original height. Then it spends a quarter of an orbit rising higher than its original height. Then it spends a quarter orbit dropping to its original height. The object thrown away spends a quarter orbit rising to its hightest point. It spends the next quarter of its orbit dropping back to its original height. It spends the next quarter orbit dropping to its lowest point. It spends the next quarter orbit rising t

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