Element 21 Golf.

Next time I won’t do the math in my head.

jbs

My money is still on the station’s constant orbit maintenance vs. the golf ball’s nonexistent orbit maintenance (drawing ever downward to a burn-up in the atmosphere) make the collision aspect as close to a non-issue as possible (that is, it’s in the noise when compared to the chances of other collisions).

jbs

Assuming precession can take place quickly (within the four year expected orbit of the ball) the orbits can eventually cross at nearly right angles. I drew a picture (with a back ground supplied by Celestia) of such orbits (click on the word picture).

I don’t know how likely the orbits getting this out of sync is. Imagine two 17000 mph orbits intersecting at a right angle. Top of the head estimate is about 8500 mph closing speed (what’s that, about 4 km/s?).

jbs

jbs

Thanks, Tom and NelC. Okay, I think I get it. Now if ballistic coeffecient depends on mass to surface area, in a golf ball that should be a lot higher ratio than a solar array (I’m assuming). So you’re saying its orbit would decay faster, right?

And it’s the angle that matters when we consider the speed. That…actually makes sense, which probably means I’m kidding myself about understanding.

*considers*

It still sounds pretty darn unlikely that it’d ever be seen again, I must say. Let alone hit the Shuttle. But it’s a silly stunt all the same.

I have no idea how you’d do this with a single impact, but if you could get the orbit of the golf ball to start precessing such that it winds up with the same altitude and inclination, but opposite nodes at collision, it would hit head-on, which means an impact at ~53,000 ft/sec (~16 Km/sec).

- Jack

Let’s suppose the ball hits and damages something, who is legally responsible, who will have to pay for the repairs? Will it be the golf compagny?

If so, do you think they’ll have to raise the price of their golf balls to cover for the multi-billion dollars loss…?

The orbit will decay from interaction with the very tenuous atmosphere; the ball has a high surface to weight ratio ,so it will decay faster than the station, and it won’t be able to correct its orbit. Somebody around here said 4 years, which sounds reasonable.

Don’t know about the camera lens cover, but if it was dropped it probably had a velocity difference of a few cm/s, so I doubt it would have done any damage.

That aside, essentially I agree with Tom. I’ve flown the shuttle simulator software about 30 times, launch, orbit, rendezvous, deorbit, land (only landed successfully once) about 20 years ago. To deorbit, you flip the thing end-for-end (shut the bay doors, dummy!), decline about 23 degrees, then do an OMS burn for between two and three minutes. Shooting the ball both backwards and down is the only way you’re ever going to reach atmosphere, unless you leave the damn ball INSIDE the shuttle where it neither belongs, nor should have ever been. (sigh)

I love space. I’d like to live in an L-5 Colony. People that actually GET there ought not make a mockery of it and jeopardize the chance for all the rest of us to get there in our lifetimes…

If the ball and another spacecraft are at the same orbital altitude (circular assumed), then they are traveling at the same speed. If their inclination (angle made when they cross the equator) is different, then at the points they meet, their relative velocities can be very high. An example of the maximum (it’s impossible in this situation) would be an object in a 0 degree inclination, flying directly over the equator, striking an object with a 180 degree inclination, flying directly over the equator in the other direction. That would mean a closing speed of 36,000mph.

Orbits do decay, but the predictability varies quite a bit. I seem to remember that astronauts released a solar array during the first Hubble repair, and it stayed up much longer than people expected. The major variables are the expansion of the atmosphere and the ballistic coefficient of the object. A golf ball has a fairly high ballistic coefficient (compared to a plastic sheet of the same mass), so it could orbit for a while.

As I mentioned before in my 3/7 6:29 post, the differential speed, which translates to force shouldn’t be that high. It’s true that the speed and orbit of the ball will change over time, but while that would increase the collision speed it will also serve to move the ball away from the station.

Orbit mechanics plays with your mind.

First, I don’t understand this thing about the golf ball going at 18,000m/h. I mean, I do, it’s leaving at the same velocity that the shuttle is going and there’s whatever acceleration the cosmonaut gets on the ball, but isn’t everything up there going at that velocity too? Everything that’s staying in orbit, anyway. It’s not like the Shuttle is standing still and along comes this golf ball at 18,000 m/h, right? Or am I missing something?

Second, I don’t fully undertand orbital mechanics, but don’t orbits decay unless you keep correcting them? And wouldn’t a golf ball’s orbit decay fairly rapidly?

Third, how much force could be involved here? Someone mentioned a camera lens cover that got tossed out and later hit the craft. Did it damage it?

I just *know* I’m wrong about all of this, given my non-background in physics. So go ahead, tell me where. *g*

Hawkeye

Along the same idea, on the ISS, what would a 3D game of snooker be like? Granted it would be ‘indoors’, but I guess those balls would keep going until all dropped into the pockets. A long game I suppose with no chance of the opponet even getting a shot, even if the black ball dropped ‘ in – off ‘. Though he would win, it would not be much of a game.

But it would pass the time when you couldn’t play golf outside during a meteor shower! arrr, sorry ’bout that Phil.

Ivan.