Hacker News Reader

Comment by artwr | Hacker News Reader

That's going to be interesting to see if others follow this as an anchor or buy more into the hype. Regardless it's still a large multiple of earnings...

View on HN

There's a finite supply of space before we lock ourselves in with trash

The risk here is severely overblown. Low earth orbit is self-cleaning with atmospheric drag. There’s comparatively little in MEO and even in a catastrophic Kessler syndrome scenario it’s still safe to transit through. Polluting higher orbits is so far beyond our current capabilities that it’s not even worth discussing.

This is the first time I’ve ever seen someone downplay Kessler syndrome so matter-of-factly. Has anti-doomerism spread to nearly every topic, or is Kessler syndrome really something whose severity has been massively overstated? Opportunity to shift my priors I suppose.

Kessler syndrome is way overstated. One way to tell is talk about it closing off space. That can't happen, it is possible to cross debris bands with low danger.

People also don't talk about different orbits. We can use higher low earth orbits if lower orbits are blocked.

Also, it is possible to clean up debris. The low cost launch means lower cost cleanup. My understanding is that big objects are most dangerous cause they would cause a lot of debris.

Kessler syndrome doesn't "work" with the orbits these sats sit in. Even left dead and tumbling, the sats would re-enter by their own in ~5 years time. Even less with the recent lowering of their operational orbits.

Also, a common misunderstanding of orbital mechanics (probably amplified by otherwise great cinematography, but poor physics depictions movie Gravity) is that after a collision things move to higher orbits and thus remain up there forever / change planes and affect other satellites. But that's not how it works, the orbit gets elongated, but the periapsis remains the same (or slightly lower), so the things / parts / pieces still re-enter the atmosphere. And the satellites are grouped in rings, with different inclinations, making it extremely hard to reach one from the other.

Also also, space is like really really big. Plenty of space (hah) to put lots of rings of satellites and coordinate between themselves up there. The operators are the first ones who care about it, and they're slowly improving the existing systems, in both tracking (and access to tracking) and automated collision avoidance. Having 10k sats up there makes you good at keeping them separated.

Low earth orbit includes orbits that take from hours to centuries to decay, depends a lot on altitude/apogee/perigee. Starlink for multiple reasons places satellites in the range where it takes ~5 years to decay, thankfully. Kessler syndrome is real though, and satellites do collide or break apart in LEO.

To take the opposite angle of the other reply, if we lock ourselves in with trash, then orbit will be fucked for everyone. That's not something that SpaceX could plant their flag in and then be the only one to use it. If Kessler syndrome happens, SpaceX would be just as worthless as any competitors they might currently have an edge over.

Reply on news.ycombinator.com