Prof. Sam LawlerJul 3

New SpaceX report on Starlink conjunctions and deorbits (a.k.a. dumping tons of metal/plastic/solar panels/computers into the upper atmosphere) https://www.scribd.com/document/883045105/SpaceX-Gen1-Gen2-Semi-Annual-Report-7-1-25

Scariest part:
472 Starlinks were burned up in the atmosphere in Dec-May. Assuming each satellite is 800kg, and 50% aluminum by mass, that's 1 ton of aluminum PER DAY.

The natural infall rate of aluminum from meteoroids is 0.3 tons per day. Starlink has been ~3x that, for the last 6 months.

SpaceX Gen1-Gen2 Semi-Annual Report (7!1!25) | PDF | Satellite | Space X

SpaceX FCC doc

Scribd
Show threadProf. Sam LawlerJul 3

Kessler Syndrome update:
They report 144,000 collision avoidance maneuvers across the whole constellation in Dec-May. That's about one maneuver every 2 minutes.

Every 2 minutes there's a chance for a mistake that would lead to a very bad day in orbit. And as this paper shows (with Dr. Kessler himself as a co-author!), a very bad day at that altitude would lead to a runaway collisional cascade. No more satellites at that altitude! https://conference.sdo.esoc.esa.int/proceedings/sdc9/paper/305/SDC9-paper305.pdf

Show threadProf. Sam LawlerJul 3

SpaceX spends a lot of time saying how safe they are with their threshhold for collision avoidance maneuvers, which is great. But they HAVE to be! With those densities, high collision probability conjunctions happen many times per day. It is impressive that they have been operating perfectly, but how long do they think they can keep this up with zero mistakes?

And what if all the Starlinks are not all fully burning up as they claim? That's a lot of stuff hitting the ground...

Show threadScottMGSJul 3
@sundogplanets Unfortunately, I think *they* think that since they've done it so far they can keep doing it forever. How they think they'll do when they have to dodge not only their huge constellation but Amazon's and China's (etc.), is anyone's guess. Especially if everyone starts locking down their orbital information like your post yesterday kind of implied!
Show threadTodd Heberlein (social)Jul 3
@ScottMGS @sundogplanets Is there a legal framework in place to address what happens if satellite collisions from one companies (i.e., Starlink) cause debris that damages satellites from another company (i.e., Kuiper/Amazon)?
Show threadScottMGS
@toddheberlein @sundogplanets This is *way* outside my area of expertise but the Outer Space Treaty (https://en.wikipedia.org/wiki/Outer_Space_Treaty) is the only thing I've heard of. Not sure it covers what you're asking but my understanding (based on what I read in A City on Mars by Kelly and @ZachWeinersmith) is that the country the space objects are launched from is legally? financially? responsible for damages caused but that might only apply to damages on Earth, not beyond it. But don't quote me on that!
Outer Space Treaty - Wikipedia

Jul 4 at 1:04pmWeb
Show threadProf. Sam LawlerJul 4
@ScottMGS @toddheberlein Further reading: https://www.cambridge.org/core/books/who-owns-outer-space/960CCB0464744F845B09434D932699EC
Who Owns Outer Space?

Cambridge Core - Astronomy: General Interest - Who Owns Outer Space?

Cambridge Core