Russian cosmonauts toss old equipment overboard on International Space Station spacewalk

[Admin]

Russian cosmonauts Sergey Prokopyev and Dmitry Petelin worked outside of the International Space Station to remove and toss overboard a trio of outdated devices, including a spent science experiment.

Russian cosmonauts toss old equipment overboard on International Space Station spacewalk : Read more

 

[David P L]

You can't just toss stuff overboard. They're just giving it a slightly different orbit, which will probably intersect with with the ISS in the future.

 

[Pietko]

ehm... maybe not... because it will slowly deorbit due to highly rarefied atmosphere... Still it will continue slowly on lower and lower orbits in the course of a few years.
I agree that this is not a good habit to litter around...

 

[Unclear Engineer]

It would have been useful if the article had given the projected remaining lifetime in orbit for the equipment that was "thrown away" as described. Presumably, it was pushed away in the opposite direction from the forward path of the ISS in its orbit. That would give it a more elliptical orbit, with its highest point being the ISS orbit and the lowest point getting closer to the atmosphere and increasing its drag while there. That drag reduces the high and low points in the junk's future orbits, until its low point gets to where it slows down enough to re-enter and burn-up. But, until then, it is a potential hazard to other, useful things in orbit, and should be tracked. So, how long is that period from jettison to burnup?

 

[AltBren]

Would it be useful to have some kind of cannon, to eject the rubbish in a specific direction with a bit of welly.. it could be used to make adjustments to it's trajectory and ensure the rubbish isn't a space junk issue.

 

[Pietko]

Would it be useful to have some kind of cannon, to eject the rubbish in a specific direction with a bit of welly.. it could be used to make adjustments to it's trajectory and ensure the rubbish isn't a space junk issue.

Deorbit takes about year from 400km
But it depends on a few factors. Overall mass and density of object, shape, solar activity...
Small, high density objects take long time to deorbit from that height.
Low density objects take short to deorbit... or they may be even pushed to interplanetary space(solar sail like very light objects with very large surface).

 

[wagonmaster]

ehm... maybe not... because it will slowly deorbit due to highly rarefied atmosphere... Still it will continue slowly on lower and lower orbits in the course of a few years.
I agree that this is not a good habit to litter around...

And what will it run into on the way down? A three layered low orbit group of satellites. An old camping saying applies "Pack it in, Pack it out". All such materials should be returned back to the ground for disposal

 

[Pietko]

And what will it run into on the way down? A three layered low orbit group of satellites. An old camping saying applies "Pack it in, Pack it out". All such materials should be returned back to the ground for disposal

We all know that russians do not care.

 

[BenN]

Russian cosmonauts Sergey Prokopyev and Dmitry Petelin worked outside of the International Space Station to remove and toss overboard a trio of outdated devices, including a spent science experiment.

Russian cosmonauts toss old equipment overboard on International Space Station spacewalk : Read more

So a couple of years to deorbit. They don't care but they should hear us complain.

 

[billslugg]

If the astronauts pushed the debris backwards at, say, one meter per second, then by 1/4 of an orbit, it is already about 500 meters lower. At 2 km lower per orbit, it is not going to last very long, maybe a week or so.

 

[HelpDPlanet]

You can't just toss stuff overboard. They're just giving it a slightly different orbit, which will probably intersect with with the ISS in the future.

I am a bit surprised that tossing stuff is a thing. If you look at a map of all of the junk orbiting around the planet, it is frightening. I guess "pack it in pack it out" is only for us landlubbers.

 

[YouMustBeBlind]

She really said "Oh its heavy".... Cause its not supposed to be weightless or anything.
The "earth" below them isn't even moving. How fast is the ISS supposed to be moving as it "orbits earth"
Watch as a piece of equipment slowly floats away... Don't worry about any of the other thousands of satellites "orbiting earth"
These videos are so cheap and fake its not even funny.
NASA needs to hire better video editors. Bring the Hollywood production team back in.

 

[Homer10]

This is not a good thing to do. When you are in orbit, You are in orbit with all the things around you. If you toss an object off the ISS, it effectively enters a different orbit, which means the object you threw away will come back when your orbit takes you around to the other side of the Earth. Twice during the ISS orbit this equipment will come back to the ISS (maybe bump into the ISS). It will come back with the kinetic energy it received when it was thrown. They just created more space junk that needs to be tracked. Unneeded equipment needs to be packed into a Cignet cargo capsule, and reentered back into the Earth's atmosphere where it will no longer pose a risk. Another dumb Russian move.

 

[Homer10]

I am a bit surprised that tossing stuff is a thing. If you look at a map of all of the junk orbiting around the planet, it is frightening. I guess "pack it in pack it out" is only for us landlubbers.

AMEN! All they did was add to the space junk problem. Pack in a Cignet cargo capsule, and reenter it in the atmosphere, and burn it up.

 

[Unclear Engineer]

Homer10,

Not quibbling with the sentiment about "packing out the trash" instead of throwing it out into a lower orbit.

But, I am going to quibble with your description of the orbit the trash goes into. Orbital dynamics are rather counter-intuitive.

Assuming that the piece of junk is pushed exactly backwards from the direction that the ISS is orbiting, and that the ISS is in a circular orbit, the piece of junk will go into a slightly elliptical orbit with only its high point (apogee) as high as the ISS orbit. It will be at its lowest point (perigee) on the other side of the Earth, and it will get there a bit sooner than the ISS, because it will have a shorter orbital period. By the time the two get back to the point in the ISS orbit where the trash was jettisoned, the junk will get there first, and the ISS a bit later, because the slightly lower orbit is slightly faster, it terms of angular degrees per unit time. In addition, because the junk spent time closer to the Earth, it will also have lost energy (faster than the ISS) so it will not get as high at its apogee and would be somewhat below the ISS orbit, even at apogee.

This back-of-the-envelope analysis assumes that the density of the parts is about the same as the ISS, so they react to the drag of the very thin atmosphere about the same. As Pietko posted previously, things that are light mass and large surface area would tend to slow down faster due to drag, but also could respond to solar pressure more and could actually "solar sail" into much different orbits.

 

[murgatroyd]

So if I understand correctly, the objects tossed by the cosmonauts from ISS will NOT pose a threat to ISS itself. But they could, in principle, intersect orbits of satellites or debris below? A Starlink satellite could then take evasive maneuvers, but what about a piece of debris that has no such capability of evasion?

 

[Unclear Engineer]

So if I understand correctly, the objects tossed by the cosmonauts from ISS will NOT pose a threat to ISS itself. But they could, in principle, intersect orbits of satellites or debris below? A Starlink satellite could then take evasive maneuvers, but what about a piece of debris that has no such capability of evasion?

Exactly!

And, because satellites (and junk) have orbits with various inclinations (to the equatorial plane), there is a lot of "crossing traffic". So collisions are potentially at very high speed differentials, potentially making a lot of smaller debris that is harder to track and avoid. That makes observable pits on solar arrays on satellites.