Brutkey

Prof. Sam Lawler
@sundogplanets@mastodon.social

Here's a (messy, quick, not peer-reviewed) animation I threw together* using one of AST SpaceMobile's requested orbital configurations. These AST satellites are so bright that if you were standing in downtown Toronto on the summer solstice, in the night sky you'd be able to see the moon, Venus, and a handful of AST SpaceMobile satellites all night long.

*the code was part of a peer-reviewed paper: https://iopscience.iop.org/article/10.3847/1538-3881/ac341b

Prof. Sam Lawler
@sundogplanets@mastodon.social

RE: https://mastodon.social/@sundogplanets/115748537218476769

Here's a nice, angry op-ed I got invited to write for Nature about AST SpaceMobile's first stupidly bright satellite a couple years ago: https://rdcu.be/drQOU

And just a reminder, if you're half as pissed off about stupidly bright satellites as I am, DarkSky International has an open letter to Reflect Orbital and their investors that you can sign here:

Prof. Sam Lawler
@sundogplanets@mastodon.social

DarkSky International just posted their position letter on Reflect Orbital. It is direct and to the point:

"Based on current scientific evidence, DarkSky does not see a viable pathway for such systems to align with responsible lighting principles or with our mission to protect natural darkness. These systems would introduce significant ecological, human health, safety, and astronomical risks at a global scale."

Read their letter and add your name here:

https://darksky.org/news/organizational-statement-reflect-orbital/

Prof. Sam Lawler
@sundogplanets@mastodon.social

Are direct-to-cell satellite connections useful? Yes. Are the benefits for a small handful of people who can afford access to those satellites worth the increased collision risks in orbit, the atmospheric pollution from launching and reentering all of them, the ground casualty risks from reentering them, and the light/radio pollution they cause? I would argue, no. Invest in better remote ground-based infrastructure! This scramble for direct-to-cell sats is NOT going to work.

Prof. Sam Lawler
@sundogplanets@mastodon.social

Damn, looks like the freaking huge AST satellite launched successfully. I guess we'll find out soon how incredibly fucking bright and radio-loud it is 😭

https://fed.brid.gy/r/https://bsky.app/profile/did:plc:vqtp5dj2o6rqnge56sz2db5a/post/3mapcxxetwk2o

Prof. Sam Lawler
@sundogplanets@mastodon.social

...and how hardy it is to debris hits. That's a big cross-section: 2,400 square feet, a bit bigger than a basketball half-court. This paper https://www.sciencedirect.com/science/article/pii/S027311772030644X suggests 1 hit energetic enough to penetrate 1 mm of aluminum per m^2/yr from debris and 1 from micrometeorites at AST's altitude, so about 1 hit per day. Good luck...

(Especially given a much smaller Starlink satellite and the similar cross-section Chinese space station both likely got hit by debris in the last few days)