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Potential collision of space junk


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10 hours ago, RPM said:

I'm surprised they haven't developed a system to capture and de-orbit large junk. Some sort of drone to match speed, deploy a net and drag it to a fiery death.


 

You would think! Fuck other stuff but just the impact on space flight is bad enough that they should have done something already, let alone all the other bad things coming from it as well. 
 

Unless you want to get wigged out, don’t dig too much into all the space junk. 
 

Think it’s bad now? Here come all the min/micro satellites and bullshit ramping up too.  Space in space is becoming prime real estate.

 

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On 10/16/2020 at 3:13 AM, RPM said:

I'm surprised they haven't developed a system to capture and de-orbit large junk. Some sort of drone to match speed, deploy a net and drag it to a fiery death.

They have, there are multiple research projects testing concepts for this, some have flown demonstrations already. The difficulty is one of orbital physics - unless you specifically target pieces of junk and match their orbit, A. you never have a chance to come close enough to collect them, and B. anything you hit in a random other orbit is moving so fast relative to you that no material on earth can catch and contain the kinetic energy.

The incident in the OP is a great example of the difficulty - you had 2 objects on near-miss trajectory and A, they still missed, so you would have missed your grab, and B, they were moving at 33000 mph - nothing is going to 'catch' something going that speed.

There is a large amount of awareness now regarding space junk. The focus is on keeping the "junk" satellite in one piece and disposing of it, instead of having it break apart into many uncontrollable pieces. Some projects are focusing on being a "space tug" that can then target each satellite orbit, grab it, and tow it to a graveyard orbit or tow it to deorbit. Most modern satellites have End of Life (EOL) or deorbit as a distinct item in design. Fuel reserves are specifically saved for final EOL maneuvers, either to a graveyard orbit high out of use, or deorbit. If the final plan is deorbit, satellite components are designed to burn away on reentry, no large solid masses are allowed to survive through reentry, or deorbit is controlled enough to put surviving masses into the ocean and not over land.

SpaceX Starlink is designed to burn away completely, and their orbit is low enough that even if the lose control or break apart, their debris will deorbit itself in roughly 5yr. Some of the large commuications or imaging satellites are MUCH higher orbits where there will be no natural deorbit for thousands of years.

Other projects are investigating large deployable 'nets' where you could go to an important orbital lane and "sweep" it to gather up junk. Again the difficulty of closing speeds - you can be in the same orbit but still have too much speed for anything to be caught vs punching holes in the net. And if you fail, you just added pieces of net to the debris field.

 

Finally, any mention of space junk needs to mention this incident. In 2007, China shot one of its own satellites to prove an anti-sat missile system. The resulting debris makes up a full 1/3 of all tracked objects in ISS-risk orbit. A few shotguns of debris like this in common orbital lanes could effectively deny space to everyone if someone were to decide to go 'scorched earth' on space assets:

https://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_missile_test

 

Ultimately keeping orbit clear is going to require everyone be responsibile with their shit in orbit.

 

Edit: Bond figured out safe orbital practice 50yrs ago!

You-Only-Live-Twice-763.jpg

Edited by Sam Lin
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18 minutes ago, Sam Lin said:

Bond figured out safe orbital practice 50yrs ago!

That was the sort of "capture" I was thinking of. Slow approach from rear then overfly. I'm aware it would be incredibly difficult and only viable on larger objects.

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This is one company that has actually launched a space tug that can help move satellites that are out of propulsion - in this case the tug will help the satellite remain in useful orbit for 5 additional years, and then will move it to graveyard orbit.

https://phys.org/news/2019-10-life-geosynchronous-satellites.html

 

Edit: A lot more mission detail here, latest updates near bottom, but the relocated satellite was put into service April of this year. MEV-2 has also been launched.

https://directory.eoportal.org/web/eoportal/satellite-missions/m/mev-1

Edited by Sam Lin
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The problem is that there are essentially "four classes" of orbital debris:

  1. ACTIVE satellites/spacecraft (not really debris, but still need to account for them!)  
  2. INERT objects - those that are still fully intact, but not performing any useful function - this includes spent rocket/booster bodies that finished their job boosting satellites to higher orbits, but are still hanging around and orbiting the earth.  The Russians and Chinese are guilty of not providing planned deorbit capabilities for most of theirs.  We "used to be" bad about that, but have gotten much better about adding that little bit of fuel budget to nudge our spent boosters into a decaying/re-entering orbit to burn up after they're done.
  3. LARGE collision debris - chunks of things from collision events.  This is actually a much smaller number than you might think (see that "space is big" comment above).  There have been a relatively few "collision events" and most of those occurred low enough to where the debris was scattered and ended up deorbiting relatively soon after.
  4. REALLY HARD TO TRACK debris - the unclassified tracking limit is roughly softball-sized... the classified limit is obviously much smaller.  I could tell you about it, but then I'd have to kill you.  So, things much smaller than rocket bodies - all the way down to (no kidding) flecks of paint are included in this group (the classified tracking doesn't account for paint flecks). 

The only categories above that we can plan for doing something about are the first two.  And, for our part, the US (and EU... essentially everyone *but* the Russians and Chinese) try to be good stewards of the Low Earth Orbit (LEO) environment with regards debris.

Challenger, on STS-7, noted a debris impact post-flight on one of her windows.  It was a whopping 2.5mm in diameter.  Detailed analysis was able to determine it was from a paint fleck ... and further analysis of the COLOR of the paint fleck (!!!!) indicated that it was the same crappy green color that most Russian boosters were painted.  So ... the Rooskies attacked Challenger with paint.

 

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11 hours ago, Pato del Muerto said:

Instead of pulling them into the atmosphere, would it be too difficult to propel them all out of earth’s orbit and into deep space in all directions like breadcrumbs?

That would produce way too many Vgers for the future human race to handle.

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On 10/20/2020 at 10:12 PM, Pato del Muerto said:

Instead of pulling them into the atmosphere, would it be too difficult to propel them all out of earth’s orbit and into deep space in all directions like breadcrumbs?

In short, yes. Actually getting out of orbit takes a LOT of energy.

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9 hours ago, Sam Lin said:

In short, yes. Actually getting out of orbit takes a LOT of energy.

Yup -- it's literally only a little over 1% difference between being "in orbit" and "re-entering" (at least in LEO altitudes, more as you go higher, but it only takes the low/perigee end of the orbit to reduce into the atmosphere to deorbit), so that's much easier to budget for and execute.

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  • 2 weeks later...

Coming to this thread late but the paint fleck and the story of the Chinese blowing up a satellite to account for 1/3 of space junk have always made me think of  how much we must not know is out there.  If they blew up a satellite, there must be a ton of debris that I would think we have no idea is there, say the size of a small wing nut or screw.  Tiny, but 1000 times more massive than a paint fleck that nearly cracked a shuttle window.  I always think we are going to have a day when there is a chain reaction of debris in space crashing into each other knocking out satellite after satellite.

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Update on the Mission Extension Vehicles, satellites intended to dock to other satellites and extend their usable life by being 'tugboats' for orbital positioning (and also provide additional electrical power!) One has been active a year, the other just docked a week ago. Cool photo of the receiving satellite near the end of the article. This, combined with the decreasing cost of launch driven by SpaceX, has huge potential to spur a fundamental change in satellite design and life planning.

https://arstechnica.com/science/2021/04/the-era-of-reusability-in-space-has-begun/

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Space junk revealed by University of Texas graph database

Even though this isn't anything ground-breakingly *new*, per se, it's still very cool and good job to the Aerospace Engineering department guys for doing it.  Keep in mind that these are the "unclassified" tracking size elements.  There are many many more objects that are much smaller are are either not able to be tracked (due to size) or aren't represented in this database (to protect the minimum tracking size capabilities by our space assets).

AstriaGraph

 

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5 hours ago, Hate said:

Jesus.  That is cool but it also just can't be good.  Isn't there anything that can be done with the inactives?

It's a pretty hard problem, and a modern day tragedy of the commons. Orbital debris is a negative externality that you can ignore in a single case, but each collision and poorly designed mission/launch only worsens the problem. The things orbiting are at a high energy state and we don't currently have any scalable mechanisms to remove energy from that system to deorbit the debris.

Maybe some sort of directed energy weapon (read: frikin lazer beams) could be used, but it's not really something that has a solution yet

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The problem with grand ideas like this is from terrestrial thinking.  People don't realize the amount of energy required to change planes, altitudes, and phase angles to catch even the most obvious "refueling targets".  And, unless the systems were designed with robotic/remote refueling from the beginning, don't expect any sort of commonality or easy access to any refueling ports. 

This isn't a standardized industry where the nozzle on the local gas pump fits EVERY car on the market by design.  Spacecraft designers work with what they have and what they can afford to produce what they're required to produce.  Commonality with someone else's future refueling bot isn't "a thing" yet.

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The problem with grand ideas like this is from terrestrial thinking.  People don't realize the amount of energy required to change planes, altitudes, and phase angles to catch even the most obvious "refueling targets".  And, unless the systems were designed with robotic/remote refueling from the beginning, don't expect any sort of commonality or easy access to any refueling ports. 
This isn't a standardized industry where the nozzle on the local gas pump fits EVERY car on the market by design.  Spacecraft designers work with what they have and what they can afford to produce what they're required to produce.  Commonality with someone else's future refueling bot isn't "a thing" yet.
So it IS rocket science??
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