[staunton]

> quick to de-orbit in the case of disaster or destruction.

In case of destruction, the satellite breaks up into many individual pieces each having a potentially very different orbit. Many of those parts might then stay up longer than the satellite would have if it remained intact. The parts can also cause a chain reaction which eventually breaks everything in low earth orbit.

[mkaic]

Starlink satellites are placed in extremely low orbits specifically to avoid their becoming dangerous space-junk — their orbits are intended to decay after around 5 years, at which point they burn up in the atmosphere and leave no debris behind in LEO. Future iterations of the satellites may have even shorter lifetimes as launch costs get cheaper.

[maxglute]

Starlink V1 was placed in low orbits because it was cheaper / constrained by F9 payloads (not only reason by imo primary).

Starlink V2 is 1000-2000km orbits with expected deployment of 12000 sats.

[ricardobeat]

Starlink V2 already started deployment back in 2023, and they actually requested lower orbits (~350km) in order to reduce latency.

Moving to 2000km would be a massive downgrade in performance, I'm not able find any source for that, everything points to the next generation (V3) being deployed via Starship at that lower altitude of 350km.

[maxglute]

Apologies, I got 2000km confused with another megaconstellation, later rollouts / V2s+ are suppose to be up to 1200km, which was initially filed / granted with FCC. They did request/allow to move some of of larger v2s to lower orbits, but the full megaconstellation plan won't be constrained to <350km simply because there aren't enough orbit slots (as managed by UN/ITU) for the constellation size star link envisions. Below is recent image of current starlink distribution. Most are 400-500km and above, i.e. much longer decay times. My understanding is they're throwing v2 "minis" which still weight 3x more to lowerish orbits because that's most economical for F9 delivery, but once they have more payload via starship, full size v2+ is going 500km-1200km. 500km more altitude as like ~4 milliseconds of latency, which is not nothing, but still minor vs economic benefits of more coverage with less hardware. IMO current low LEO focus isn't ... starlink being responsible, it's result of cost optimization of coverage:payload for F9. Starship will come with different set of cost optimizations, likely for higher orbits using larger hardware, but less of it.

https://imgur.com/a/VuweZZo

[vatueil]

AFAIK Starlink does not plan to put satellites in 1200 km orbits. All Starlink satellites are in orbits of 600 km or less, where any debris naturally decays in less than 5 years:

https://www.starlink.com/updates#update10

> Starlink satellites operate in a low Earth orbit below 600 km altitude. Atmospheric drag at these altitudes will deorbit a satellite naturally in 5 years or less, depending on the altitude and satellite design, should one fail on orbit. SpaceX proactively deorbits satellites that are identified to be at an elevated risk of becoming non-maneuverable. This proactive approach minimizes the number of non-maneuverable satellites in space.

[chmod775]

> In case of destruction, the satellite breaks up into many individual pieces each having a potentially very different orbit.

Depends on what you mean with "potentially very different orbit". Each piece still has to be at least on some elliptic orbit that eventually again passes through the spot where where it broke up*. If it was on a low orbit to begin with, it'll still burn up soon-ish as it decays. You cannot increase the perigee of some formerly circular orbit with only a singular application of force, nor can you increase the perigee of an elliptic orbit higher than its old apogee through the same means.

It'll take a lot to get pieces into orbits where they avoid decaying within a reasonable time span.

*Disregarding external factors like the gravitational pull of a third object, and assuming no drag and perfect point masses.

[Salgat]

During China's ASAT test, almost all of the debris remained in the same LEO orbit. The amount of energy needed to climb over 1000km to reach MEO or over 35000km to reach GEO is significant, and even then, to reach a stable orbit after the climb is very unlikely. Kessler Syndrome is always a consideration, but with Starlink it's still minimal, especially since Starlink's elevation is only 340km, while China's ASAT test targeted a satellite at 900km.

[maxglute]

Next gen starlink v2s are going to be 1000-2000km with starship. Low LEO v1s was more limitation of F9. Shooting high LEO ery expensive (PRC has HQ19s for 3000km), but realistically once US/PRC rolls out starship tier reusable payload vehicles at scale, we're goign to start seeing enough co-orbital asats being launched to guarantee kessler.

[bmicraft]

Please stop spreading misinformation.

> On December 1, 2022, the FCC issued an approval for SpaceX[66] to launch the initial 7500 satellites for its second-generation (Gen2) constellation, in three low-Earth-orbit orbital shells, at 525, 530, and 535 km (326, 329 and 332 mile) altitude. Overall, SpaceX had requested approval for as many as 29,988 Gen2 satellites, with approximately 10,000 in the 525–535 km (326 to 332 mile) altitude shells, plus ~20,000 in 340–360 km (210 mile to 220 mile) shells and nearly 500 in 604–614 km (375 to 382 mile) shells.

Source: https://en.wikipedia.org/wiki/Starlink#cite_ref-66

[maxglute]

Was not aware they scuttled 1,200km ka/ku band constellation and corrected in another reply. Either way, per your citation, the current plan still puts 10k+ objects in 400km+ orbits where debris hangs around for much longer. Primary point still stands - starlink isn't limited to sub 400km constellation and kessler syndrome risk for higher orbits is real (risk increase not linear). Especially, if starlink plan to go to 42k above currently planned 30k, most are going to be 400km+ since sub 400km orbits are taken. Unless UN/ITU increase slots, the amount of sub 400km slots are fixed, and expanding megaconstellations including future starlink expansion is going to be satuating orbits with multi year / multi decade decay.

[vatueil]

Not sure why you picked 400km? All Starlink satellites are in orbits less than 600km where debris is naturally eliminated in 5 years or less:

https://www.spacex.com/updates/#sustainability

> SpaceX operates its satellites at an altitude below 600 km because of the reduced natural orbit decay time relative to those above 600 km. Starlink operates in \"self-cleaning\" orbits, meaning that non-maneuverable satellites and debris will lose altitude and deorbit due to atmospheric drag within 5 to 6 years, and often sooner, see Fig. 1. This greatly reduces the risk of persistent orbital debris, and vastly exceeds the FCC and international standard of 25 years (which we believe is outdated and should be reduced). Natural deorbit from altitudes higher than 600 km poses significantly higher orbital debris risk for many years at all lower orbital altitudes as the satellite or debris deorbits. Several other commercial satellite constellations are designed to operate above 1,000 km, where it requires hundreds of years for spacecraft to naturally deorbit if they fail prior to deorbit or are not deorbited by active debris removal, as in Fig. 1. SpaceX invested considerable effort and expense in developing satellites that would fly at these lower altitudes, including investment in sophisticated attitude and propulsion systems. SpaceX is hopeful active debris removal technology will be developed in the near term, but this technology does not currently exist.

> https://sxcontent9668.azureedge.us/cms-assets/assets/figure_...

> Fig. 1: Orbital lifetime for a satellite with a mass-to-area ratio of 40kg/m2 at various starting altitudes and average solar cycle.

[dotancohen]

It is perigee, not apogee, that matters for the lifetime of a satellite. In case of collision, it is near impossible for any object ejected to have a higher perigee than that of the original satellite. Some energetic particles might have higher apogees, sure, but that will not affect their time to deorbit.