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Clearspace-1 space debris cleanup target struck by space debris

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Re: Clearspace-1 space debris cleanup target struck by space debris

#11

Post by TomK32 »

bckr wrote: post #7
liquidise wrote: post #2

In N. Stephenson's Seveneves, a major plot point was that sufficient falling debris can superheat the atmosphere. Granted, we've orbited a trivial fraction of the Moon's mass, but have we orbited enough material to cause any warming to the atmosphere upon re-entry? Are we many orders of magnitude away? I'm frankly not even sure how to napkin math such a question.

Oh come on man, I'm on page 21.

Stop reading it after Part 2, I had the same feeling about Part 3 as this critic for the The Guardian did: "Once we arrive in the novel's snail-paced last third, there are lots and lots of lavish descriptions of imaginary machines: city-sized orbiting habitats, giant pendulums reaching down into the Earth's atmosphere, 'sky trains'. After scores of pages of this, my eyelids were succumbing to a powerful gravitational force."

Re: Clearspace-1 space debris cleanup target struck by space debris

#12

Post by uhhhhhhh »

coumbaya wrote: post #9
mrguyorama wrote: post #5

Earlier quoted context omitted.

Why would it be 2x? In terms of gravitational potential energy, you get out exactly what you put in, minus things like friction and air resistance. Also the vast majority of the energy in an orbiting body is not in gravitational potential energy (not that you said that) but in the kinetic energy of the object moving at something like 4.75 miles per second. The end result is that the energy an object decelerating back…

Well not 2x as the deceleration is 2x, but in total like you said, you put energy rocketing it up and sideway fast, it uses that same amount of energy going down.

Most of the energy used to put it into space was to push the fuel and delivery vehicle mass not the payload, that is not present on return.

Re: Clearspace-1 space debris cleanup target struck by space debris

#13

Post by yencabulator »

mrguyorama wrote: post #6

Sending up a whole rocket/"catcher" for every single bit of space debris you want to deorbit cannot possibly work. What other options are there?

Their goal is to develop a reusable craft, this is a single-use prototype. I don't think they've published any concrete plans for how they'll achieve reusability.

Maybe a future version of the catcher would have a large/refillable gas tank that lets it catch things, change their trajectory just enough to hasten their descent, and then continue on mission?

A no-fuel way to drag things down would be even better, like the sibling comment talks about tethers. Imagine a catcher that attaches a tether line that slows down LEO objects purely by drag.

Adjusting orbits to match multiple satellites is a tough requirement, with a heavy delta-V cost. Especially more so if it needs to get to a deorbiting trajectory in between each catch.

Re: Clearspace-1 space debris cleanup target struck by space debris

#14

Post by liquidise »

didgeoridoo wrote: post #8
liquidise wrote: post #2

In N. Stephenson's Seveneves, a major plot point was that sufficient falling debris can superheat the atmosphere. Granted, we've orbited a trivial fraction of the Moon's mass, but have we orbited enough material to cause any warming to the atmosphere upon re-entry? Are we many orders of magnitude away? I'm frankly not even sure how to napkin math such a question.

About 3,000 metric tons in LEO[0]. Don’t worry about mass above LEO, as there’s far less up there and it’s not decaying any time soon. LEO velocity is about 8km/s. Plugging that in to mv^2 gets you about 200 trillion joules of kinetic energy. Assuming the chemical (burning) energy contained in space debris is negligible, that 200 trillion joules is the maximum energy you’d transfer to the atmosphere if all this debri…

What a wonderful response to return to. Appreciate the work you put into this.

Re: Clearspace-1 space debris cleanup target struck by space debris

#15

Post by the_third_wave »

mrguyorama wrote: post #6

Sending up a whole rocket/"catcher" for every single bit of space debris you want to deorbit cannot possibly work. What other options are there?

Why, MegaMaid™ [1] of course!

[1] https://www.youtube.com/watch?v=O7aeWQCF1jM

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