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TheCrimsonSteel t1_jbydo8k wrote

Reply to comment by CollegeIntellect in Scientists call for global action to clean up space junk by thebelsnickle1991

Curious to pick a proper engineers brain as my main experience is just the game Kerbal Space Program

We'd have to deorbit existing junk, and maybe somehow figure out a way to eliminate the tiny junk? All the paint chips and screws and wrenches and things?

And I'm guessing most of the junk is also in the most commonly used orbits? All farirly equatorial (right term?) stuff in Low Earth Orbit?

All my knowledge of why everything's near the equator is from having to recheck my dV when I take a regual rocket setup and try to use it for a polar orbit, especially when I made my design as lean as possible

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CollegeIntellect t1_jbyif9a wrote

Tiny stuff is incredibly difficult to track and deorbit. There was one suggestion of using a reinforced solar sail or even aerogel to capture the tiny debris in orbit. It is incredibly difficult to go out and just say you’re going to clean up LEO of all paint chips. It is much easier to add reenforcement to your existing hardware or using debris agnostic designs.

NASA and DoD tracks everything larger than about 2 inches. If the object is greater than 4inches they plan on object avoidance maneuvers, otherwise they let ballistic shields handle anything smaller.

There are plenty of dead satellites out there in LEO that will eventually make their way back to earth from drag. All of those missions are grandfathered in to the old 25 year rule.

In real life, equatorial orbits aren’t very interesting. Most commonly satellites sit in sun synchronous orbits. This gives you the same angle of the sun to power your panels and observe the earth with the same lighting year round. It works because the earth is oblate and slightly causes the orbit to precess around the planet. Inclination is about 98 degrees.

Due to the limitations of kerbal, it’s not possible to get into that orbit. Gamers would be pretty mad if the game started taking into account orbital precession causing their orbits to change around the planet as they time warp through the year.

Source: https://www.hindawi.com/journals/amse/2013/484153/

Source: https://www.nasa.gov/mission_pages/station/news/orbital_debris.html

Source: https://space.stackexchange.com/questions/33704/distribution-of-satellites-by-inclination

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TheCrimsonSteel t1_jbymxam wrote

Man, one single post scratching every itch in my brain - nerdy generalist, mat sci engineer, and gamer. I do love Reddit

I'm guessing, depending on details, that ballistic shielding is generally designed to not cause further debris and sort of optimized for toughness? Assuming it doesn't impact the base protection and functionality of protection

And now I'm super curious about debris fields and tracking, I knew we did some amounts, may have to go on a nerd rabbit hole

It is good to hear we're doing a decent amount of 25 year self termination plans. I vaguely remember there being something of a "graveyard orbit" do you know if those are those deeper orbits, or do we try to make those also into one's that'll self-deorbit?

There's a niche of Kerbal players that love shooting for hyper realism. I'm more on the end of let's see what the existing engine can do and engineer something that functions on wonky mechanics and not so much real life. Like mass driver designs that are just... broken

And any resources to recommend from real life aerospace physics that'd improve my Kerbal skills? I'd love to improve my gravity slingshot game

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CollegeIntellect t1_jbys1jx wrote

The shielding is really just two plates slightly apart from each other. When the debris strikes the first plate it vaporizes and the second plate catches the vapor. It’s called a whipple shield. That first plate prevents back splash when it strikes the second plate. This minimizes debris going back to space.

Graveyard orbits are for geostationary satellites. That are farther out, if I remember correctly, than the standard GEO orbits. Those are premium orbits. They are tightly regulated. Unfortunately, those are way to far out to deorbit on their own. It’s something like a millennia or more before perturbations could cause it to deorbit. Going out to gather them and bring them back is a waste of current resources, hence the graveyard orbit.

If you’re looking to take some real life Aerospace knowledge into kerbal. I recommend searching for “patched conics”. This matches how kerbal models their system and will allow you to understand how they get to their dV calculations plus do slingshots in the game.

You’re in luck too, one of my favorite channels just dropped a video on space debris and debris shields here: https://youtu.be/_FFNz2q7F88

Source: https://ai-solutions.com/_freeflyeruniversityguide/patched_conics_transfer.htm

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TheCrimsonSteel t1_jbz3c6m wrote

Thanks!! And nice, I keep forgetting to sub to Real Engineering. I've stumbled onto his channel like 5 or 6 times now

If you don't know them already a few other favorites of mine are Smarter Every Day, Practical Engineering, and Kyle Hill

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