[HN Gopher] New Calculation Finds we are close to the Kessler Sy...
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New Calculation Finds we are close to the Kessler Syndrome [video]
Author : cratermoon
Score : 46 points
Date : 2024-11-20 20:33 UTC (2 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| visviva wrote:
| The paper in question is here:
| https://link.springer.com/article/10.1007/s40295-024-00458-3
|
| It adds to a pretty large body of literature around this subject,
| the gist of which is "risk is going up, but we don't really have
| a good way of estimating what that means in terms of actual
| collision rates".
| m3kw9 wrote:
| I would think newer sats will have collision avoidance
| capabilities and older ones will just crash. Maybe even clean up
| sats will be developed to collection them
| bell-cot wrote:
| With currently deployed tech, most of the smaller orbital
| debris is not (usefully) track-able.
|
| At orbital velocities, you gotta know it's coming to be able to
| avoid it.
|
| And a orbital velocities, the untrack-able stuff can still kill
| a satellite.
| michaelmrose wrote:
| Leo starts at 7.8 kilometers per second and speed plus
| secondary and subsequent collisions with very small debris
| makes it impractical. Also carrying fuel to react frequently
| would dramatically change the entire mission.
|
| If your non refuelable sat is good for 6 months it probably no
| longer makes sense to launch it.
| bagels wrote:
| Satellites fail (lost control, or spontaneously explode). Very
| small debris is everywhere and under 5-10 cm largely untracked,
| but some are working to fix this gap.
|
| There is no incentive large enough for cleanup (it's expensive,
| nobody can/wants to pay, and there are a lot of objects)
| benchmarkist wrote:
| As long as it is militarily and commercially viable then the
| number of satellites will continue increasing, regardless of what
| academics have to say about collision rates. As per usual this is
| a coordination problem and in case people have not noticed
| nations are becoming less coordinated and more insular.
| akira2501 wrote:
| > in case people have not noticed nations are becoming less
| coordinated and more insular.
|
| And what is your yardstick for measuring this? As far as I can
| tell this is the opposite of true. It's a popular national news
| meme but I don't believe it's been measured in any reliable
| way.
| bragr wrote:
| I don't know about whether it is more or less common, but
| there has been international drama over conjunctions over the
| last several years
|
| https://spacewatch.global/2021/12/spacewatchgl-share-
| chinese...
| mapt wrote:
| The current trajectory is that SpaceX proved the commercial and
| military viability of an LEO megaconstellation, repeatedly
| lowering their target altitudes and raising their satellite count
| because of debris and cell size concerns...
|
| And now the rest of the world is trying to catch up in a sort of
| arms race, and not taking any care about debris concerns. The
| most tempting orbits are the ones in upper LEO that permit them
| to launch fewer satellites.
|
| SpaceX are going to end up well under 500km (orbital lifespan: a
| decade) before things are finished, and they switched to very low
| orbit staging with SEP spiral out to reach final orbit a ways
| back.
|
| China's newest constellation Thousand Sails is at an altitude of
| 800km (orbital lifespan: thousands of years), with a thousand
| satellites in the works over the next year or so and 14,000
| planned, and they're launching them using chemical upper stages
| designed to explode into a thousand pieces at the target
| altitude. This is sufficient for Kessler Syndrome all on its own,
| without counting interactions with anything else up there. A
| catastropic debris cascade at 800km percolates down to lower
| altitudes over time and impacts.
|
| We need viable treaties limiting development beyond 400 or 500km
| and we need them ten years ago.
|
| I don't know how to sell the urgency of this predicament. You can
| have as many satellites as you want, a million uncoordinated
| bodies, at 400km because direct collision potential scales with
| (satellite count / orbital lifespan) ^2 . At 1000km, satellites
| decay so slowly we are already too crowded; we have already
| overused the space. We are speed-running the end of the space age
| and we are doing it to save a small number of dollars and to
| avoid a small amount of diplomacy.
|
| This is not something we get a do-over on. There is no practical
| way to collect ton-scale debris at present, no way to track
| kilogram-scale debris, no practical way to shield pressure
| vessels against gram-scale debris, and even milligram-scale
| debris can hit with the force of a bullet. After collisions start
| occurring at a rapid clip, the mass of potential impactors
| quickly forms a long tailed lognormal distribution that denies us
| space for centuries.
| autoexecbat wrote:
| > upper stages designed to explode into a thousand pieces at
| the target altitude
|
| By this do you mean at the 800km altitude?
| mapt wrote:
| Yes. In a lot of historical spaceflight programs, the stage
| used in the upper atmosphere stayed with you to the final
| orbit, and was detached at low speed there. This saved you
| from having to design your satellite with significant onboard
| propulsion. Some of the upper stages were able to vent
| remaining propellants or pressurants, some were allowed to
| heat up until the pressure vessel exploded.
|
| Suffice it to say this is not sustainable for
| megaconstellations in thousand years orbits. The responsible
| thing to do with that kind of scale involves reliable,
| redundant, prompt de-orbit of upper stages, and ideally for
| high-thrust, high-mass, high-engineering-margin-of-error
| atmospheric upper stages never to make it that far into the
| mission.
| bamboozled wrote:
| One way is for the the US to be more politically stable again
| (some how). Every country with an army will want its own star
| link now for trust reasons.
| mapt wrote:
| For how long?
|
| Because this thing is happening right now, it's happening
| fast, and it's happening without any effort to fight against
| the trend.
|
| If your answer is "let's revisit this in 2050", then it isn't
| an answer.
| bamboozled wrote:
| Yeah well it means a lot of satellites are going to end up
| in space then.
| leptons wrote:
| >I don't know how to sell the urgency of this predicament. You
| can have as many satellites as you want, a million
| uncoordinated bodies, at 400km because direct collision
| potential scales with (satellite count / orbital lifespan) ^2 .
| At 1000km, satellites decay so slowly we are already too
| crowded; we have already overused the space. We are speed-
| running the end of the space age and we are doing it to save a
| small number of dollars and to avoid a small amount of
| diplomacy.
|
| This sounds like the most first-world-problem ever. It
| realistically affects practically nobody alive, nor would it
| ever. Most people will live and die on the planet's surface and
| never visit space, nor do they need to. There aren't too many
| space-based services that are really necessary to life on
| earth. Nobody really _needs_ internet in the middle of nowhere.
| Sure, it 's nice to have, but that's a first world problem that
| few people have.
| nwiswell wrote:
| > It realistically affects practically nobody alive
|
| Do people in the Global South not use GPS or consume weather
| forecasts?
| Oarch wrote:
| There might be a cool storyline where we have to use enormous
| ground based lasers to clean up and start again.
|
| Could even look a bit like the iconic Gibraltar WW2 search lights
| photographs.
| jcgrillo wrote:
| What would zapping a satellite with a laser achieve? I suppose
| if you get it hot enough to melt everything, without anything
| flying off, then it would turn into a spherical drop of molten
| scrap... but then what?
| ZYbCRq22HbJ2y7 wrote:
| I assume the poster means to change its trajectory.
| sfink wrote:
| By adding energy (and momentum)? That seems unlikely to
| work. I guess you could try to shoot at things headed
| towards you over the horizon, to slow things down?
|
| I was assuming it was to vaporize things to make the re-
| condensed remnants small and dispersed enough to be less of
| a problem. Though that seems like a tough problem if you
| have to stay trained on an orbiting bolt for any length of
| time, as the atmosphere wobbles your laser around.
| aeternum wrote:
| You ablate part of it on the prograde side to create a small
| retrograde thrust which will deorbit it.
|
| I think the right move is to merge this approach with goo
| blobs. We launch a large goo blobs or nets into a few
| strategic geostationary orbits and now you only have to
| ablate objects so they hit the goo then deorbit the goo once
| it is full (or just leave it there) as they would be large
| known orbits.
| 0xbadc0de5 wrote:
| My understanding was always that LEO is much less of a Kessler
| risk due to atmospheric friction - ie: in the absence of active
| control and regular correction, LEO objects will gradually de-
| orbit themselves. It's the the higher geostationary orbits that
| pose the problem.
| resters wrote:
| Positioning a large, armored satellite in low or mid-Earth orbit
| significantly enhances its strategic value for both offensive and
| defensive anti-satellite operations. Such a platform could serve
| as a pivotal asset in maintaining orbital dominance, offering
| rapid response capabilities to neutralize threats and protect
| critical infrastructure.
|
| In other words, welcome various "death stars" to keep order
| against malicious Kessler style attacks, etc.
| donaldihunter wrote:
| I love Sabine Hossenfelder's videos but the audio effects on the
| transitions are killing me.
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