Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[MonkeyHead]

Perserverence landed, apparently safe. Next milestone is probably Ingenuity taking off...

I am stoked to see how well it works. Truly a paradigm shift.

[Strife26]

Except each single one of the tiny ones won't necessarily explode every operating orbiter it touches. Again the total mass is smaller.

And I think a uniform cloud of small bits would be easier to clean up as well. Imagine catching a couple rabbits vs sweeping up a bunch of ants with a broom.

Actually I would say a uniform cloud of small bits is way more predictable as well. There'd be some set amount of abrasion that a spacecraft could reasonably experience on its way to orbit and in orbit that scientists could engineer for, rather than just hoping a big 'un doesn't strike it at random and blow it up.

I mean, you're free to say that. You're incredibly wrong, but you do you.

[bloop_bleep]

Except each single one of the tiny ones won't necessarily explode every operating orbiter it touches. Again the total mass is smaller.

And I think a uniform cloud of small bits would be easier to clean up as well. Imagine catching a couple rabbits vs sweeping up a bunch of ants with a broom.

Actually I would say a uniform cloud of small bits is way more predictable as well. There'd be some set amount of abrasion that a spacecraft could reasonably experience on its way to orbit and in orbit that scientists could engineer for, rather than just hoping a big 'un doesn't strike it at random and blow it up.

I mean, you're free to say that. You're incredibly wrong, but you do you.

Please, offer more witty passive aggressive passes in lieu of an actual response. 

If you think I'm wrong about something I'd welcome it if you'd at least explain it to some reasonable degree.

[wierd]

He is correct though Bloop.  The small cloud of debris is much harder to effective "bag and tag" than an intact spacecraft.

Due to the extreme costs of putting something into orbit, a great deal of the outer skin of orbiting spacecraft is essentially made of mylar coated aluminium foil.  It is very easy to tear, and once torn, it allows EM and solar radiation to enter the spacecraft, which can kill it in hours. 

Small bits of debris can have sufficient kinetic energy to shred that material ferociously, and thus, can wipe out whole constellations of craft.


Small bits of space debris is really really bad juju.

https://www.sciencealert.com/the-space-debris-problem-is-getting-worse-not-better

[Arx]

It's not about being correct, it's about the fact that it'd have taken about the same amount of time to write a condensed version of your post as to write what he did write. He chose to randomly sling insults instead.

[Starver]

We'd already seen...

Large numbers of fast moving impossible to track small bits are orders of magnitude worse than larger, fewer, slower, predictable objects.

...to which bb effectively responded "on the contrary, I think...". And I'm not sure weird's clarification is any more convincing (though it should be) against that miscomprehension.

You had bb not thinking of conservation of mass, now smeared over a larger and less confined danger-'zone' in a probability curve that potentially impacts (NPI) more and more operational targets, etc. Even if a 'catcher's mitt' (or ant-broom) can be hardened to inelastically absorb any small fragments with possibly counter-orbitting velocities (polar orbits would be the worst), many more fragments will miss that (or glance off a possibly more fracturable edge of the 'mitt') and continue(/increase) their danger to unmittable craft.


I don't think my expansion helps, but if it does it does...

[thompson]

I’d put it like this: what volume of space are you trying to clean with that broom? If you can put a number on it, the rest will be obvious.

[bloop_bleep]

You mentioned conservation of mass, but remember in my example the majority of the mass would be deorbiting after the inelastic collision between two orbiting defunct satellites having shed orbital energy. The bits would just be stray offshoots that incidentally are in an orbital trajectory as a result of the collision. EDIT: In fact thinking about it, I'm not sure whether there'd be an appreciable number of bit offshoots at all... most would be shooting off radially (perpendicular to the collision) and so probably won't be in an orbital trajectory.

Though I suppose the volume of space covered by the broom is a concern.

[wierd]

If the bits shooting upwards do not have sufficient energy to do a full escape, they will fall back into the well, and gain kinetic energy as they do so. They could end up with highly elliptical orbital paths.

The same would be true of particles shot "downward", if their angle of approach to the earth causes them to "miss" the atmosphere.

[bloop_bleep]

But I was thinking that most of the time their elliptical orbit paths would intersect the earth. Because they would have mostly radial velocities.

[wierd]

The paths they take before the hit the atmosphere on the way back down (since in both scenarios, particles would be shot 'up', then fall back down again, and continue doing so until they hit the atmosphere, or something else) could have them crossing paths with healthy satellites.  This causes the mylar sheet death scenario.

[Starver]

(Ninjas as I was researching this...)

Top of my search for "typical satellite collision" for actual details was: https://en.wikipedia.org/wiki/2009_satellite_collision

"...until then, all accidental hypervelocity collisions had involved a satellite and a piece of space debris."

Note the debris patterns shown as quickly developing in the illustrations. Each satellite effectively fired a narrow shotgun (choked!) blast very much in the direction they were already going as they crossed.  Not any significant down-and-up component because there was much orbital velocity involved. (You have to nudge an orbit up or down quite a lot to easily reach air-scraping perigree, or get sufficiently raised apogee, and I doubt even head-on there'd be a neat total velocity nullification for most of the fractured and thrown-off fragments.)

"By December 2011, many pieces of the debris were in an observable orbital decay towards Earth, and were expected to burn up in the atmosphere within one to two years. By January 2014, 24% of the known debris had actually decayed.[citation needed] In 2016, Space News listed the collision as the second biggest fragmentation event in history, with Kosmos-2251 and Iridium 33 producing respectively 1,668 and 628 pieces of catalogued debris, of which 1,141 and 364 pieces of tracked debris remain in orbit as of January 2016 [needs update]"

Two years, five years, seven years and counting, there were still 65% of the (large enough to know about) bits.


(And, at the bottom, a link to a Laser Broom. Not sure if there's any further development on that concept.)

[bloop_bleep]

Huh. So turns out it was mostly an elastic collision which kept a lot of the orbital energy. I guess perhaps at those velocities the inelastic properties of metal don't really matter as much anymore?

[Starver]

At those velocities, not very much does matter as much any more, I suspect...

[Madman198237]

The physical properties of material matter very little at those speeds, yes. Chips of paint and the remnants of explosive bolts become bullets capable of punching holes in sheet metal. Collisions at orbital velocity don't obey any rules you're familiar with except maybe "with a hard enough hit, something interesting is bound to happen" which, of course, is always true