Brutkey

Prof. Sam Lawler
@sundogplanets@mastodon.social
Prof. Sam Lawler
@sundogplanets@mastodon.social
selfie (barely)

First below -40 windchill morning. Yuck.

Me looking at the camera, wearing many layers of clothes. I've got a stripey neck tube over my face which is covered with frost from me breathing, a green hat with a headlamp (also covered in frost), a black hood over all that, and a purple scarf for good measure. I'm also wearing a purple jacket over a brown work snowsuit.
Prof. Sam Lawler
@sundogplanets@mastodon.social

Just another post about the ridiculous Saskatchewan weather... (and yes, these temperature swings are exacerbated by climate change, but this well within historical norms)

30 degrees Celsius of temperature swing in just over 48 hours. Wheee.

screenshot of the 4 day weather forecast. The high for tomorrow is -24C with a low of -31C. The high on Monday is -1C with a low of -1C. WHAT.
Prof. Sam Lawler
@sundogplanets@mastodon.social

I know e-audiobooks are not a good deal for libraries so they don't purchase many copies. But I am continually baffled by what my library has. Examples:

They have books 1-4 and book 6 of the Misewa series, but not book 5

They have Project Hail Mary in Spanish, but not English or French

They have Jurassic Park in German, but not English or French

...?

Prof. Sam Lawler
@sundogplanets@mastodon.social

Fascinating replies. No doubt this is all because of enshittification!

Has anyone made an enshittification song yet? I feel like a song would not help, but would make a lot of people feel better (ok maybe just me)

Prof. Sam Lawler
@sundogplanets@mastodon.social

I know e-audiobooks are not a good deal for libraries so they don't purchase many copies. But I am continually baffled by what my library has. Examples:

They have books 1-4 and book 6 of the Misewa series, but not book 5

They have Project Hail Mary in Spanish, but not English or French

They have Jurassic Park in German, but not English or French

...?

Prof. Sam Lawler
@sundogplanets@mastodon.social

It's absolutely dumping snow right now and it's one of the approximately one million times a year I am so so so grateful the schoolbus will bring my kids home for me. Yay transit! (Now if only we had literally any other kind of rural public transit at all, that would be lovely)

Prof. Sam Lawler
@sundogplanets@mastodon.social

One of the scariest parts of this project was learning more about Starlink's orbital operations. I had always assumed they had some kind of clever configuration of the satellites in the orbital shell that minimized conjunctions, and we would see the number of conjunctions grow over time. But no! It's just random! There's no magic here, it's just avoiding collisions by moving a Starlink satellite every 2 minutes. This is bad.

Prof. Sam Lawler
@sundogplanets@mastodon.social

I'll end with the last paragraph of the paper:

"In addition to the dangerously high collision risks calculated here, we are already experiencing disruption of astronomy, pollution in the upper atmosphere from increasingly frequent satellite ablation, and increased ground casualty risks. By these safety and pollution metrics, it is clear we have already placed substantial stress on LEO, and changes to our approach are required immediately."

Prof. Sam Lawler
@sundogplanets@mastodon.social

"In the short term, a major collision is more akin to the Exxon Valdez oil spill disaster than a Hollywood-style immediate end of operations in orbit. Indeed, satellite operations could continue after a major collision, but would have different operating parameters, including a higher risk of collision damage."

This is why I did a poll here about name recognition for Exxon Valdez a few months ago! (You young'uns go read about it because many of you don't know)

Prof. Sam Lawler
@sundogplanets@mastodon.social

One of the scariest parts of this project was learning more about Starlink's orbital operations. I had always assumed they had some kind of clever configuration of the satellites in the orbital shell that minimized conjunctions, and we would see the number of conjunctions grow over time. But no! It's just random! There's no magic here, it's just avoiding collisions by moving a Starlink satellite every 2 minutes. This is bad.

Prof. Sam Lawler
@sundogplanets@mastodon.social

This really highlights how incredibly dependent we are on Starlink's continued perfect collision avoidance maneuvers. So far they've done it, but they keep adding more satellites and making it harder.

Other megaconstellations are now launching as well, and they all need to communicate PERFECTLY in order to not crash. Will China talk to Starlink? Will the US gov't secret satellites talk to OneWeb? This is all incredibly important so that we don't destroy LEO.

Prof. Sam Lawler
@sundogplanets@mastodon.social

"In the short term, a major collision is more akin to the Exxon Valdez oil spill disaster than a Hollywood-style immediate end of operations in orbit. Indeed, satellite operations could continue after a major collision, but would have different operating parameters, including a higher risk of collision damage."

This is why I did a poll here about name recognition for Exxon Valdez a few months ago! (You young'uns go read about it because many of you don't know)

Prof. Sam Lawler
@sundogplanets@mastodon.social

We set up a CRASH Clock website here: https://outerspaceinstitute.ca/crashclock/

Note that this is a probabilistic calculation. A catastrophic collision could happen sooner than 2.8 days of no maneuvers. In our (extremely computationally expensive) collision simulation, just by random chance we actually got the first collision just 3 hours in.

We are currently well inside the Caution Zone. The probability of collisions happening if no avoidance maneuvers occur is >10% in any 24 hour period.

A plot showing how the 24 hour collision probability rises at lower values of the CRASH Clock. At very short CRASH Clock values (less than about 1.5 days), the probability of a collision happening within 24 hours if no avoidance maneuvers are executed is larger than 50%.
Prof. Sam Lawler
@sundogplanets@mastodon.social

This really highlights how incredibly dependent we are on Starlink's continued perfect collision avoidance maneuvers. So far they've done it, but they keep adding more satellites and making it harder.

Other megaconstellations are now launching as well, and they all need to communicate PERFECTLY in order to not crash. Will China talk to Starlink? Will the US gov't secret satellites talk to OneWeb? This is all incredibly important so that we don't destroy LEO.

Prof. Sam Lawler
@sundogplanets@mastodon.social

The CRASH Clock uses the current density in altitude bins (averaged over eccentric orbits) of satellites, rocket bodies, and tracked debris, assuming typical cross sections for each type and orbital speeds. This calculation tells us how long to a collision if all orbital maneuvers were to suddenly stop.

The CRASH Clock is currently* at 2.8 days.

In 2018 it was 121 days.

*This is actually for June 2025 because that's when we ran it. Will update soon!

Prof. Sam Lawler
@sundogplanets@mastodon.social

We set up a CRASH Clock website here: https://outerspaceinstitute.ca/crashclock/

Note that this is a probabilistic calculation. A catastrophic collision could happen sooner than 2.8 days of no maneuvers. In our (extremely computationally expensive) collision simulation, just by random chance we actually got the first collision just 3 hours in.

We are currently well inside the Caution Zone. The probability of collisions happening if no avoidance maneuvers occur is >10% in any 24 hour period.

A plot showing how the 24 hour collision probability rises at lower values of the CRASH Clock. At very short CRASH Clock values (less than about 1.5 days), the probability of a collision happening within 24 hours if no avoidance maneuvers are executed is larger than 50%.