Hackers' Pub

Syntax	Description	Examples
`"` keyword `"`	Finds the string within quotes, including spaces. Case-insensitive. (Escape quotes inside with `\"`)	`"Hackers' Pub"`
`from:` handle	Finds content written by the specified user.	`from:hongminhee` `from:hongminhee@hollo.social`
`lang:` ISO 639-1	Finds content written in the specified language.	`lang:en`
`#` tag	Finds content with the specified tag. Case-insensitive.	`#HackersPub`
condition condition	Finds content that satisfies both conditions on either side of the space (logical AND).	`"Hackers' Pub" lang:en`
condition `OR` condition	Finds content that satisfies at least one of the conditions on either side of the OR operator (logical OR).	`#HackersPub OR "Hackers' Pub" lang:en`
`(` condition `)`	Combines the operators within the parentheses first.	`(#HackersPub OR "Hackers' Pub" OR "Hackers Pub") lang:en`

Prof. Sam Lawler @sundogplanets@mastodon.social

12/11/2025, 2:12:07 PM

Public

Two incredibly talented students led the project. We figured out a much less hand-wavy analytical way to calculate close approach rates using real data from public catalogues. And then we also ran n-body simulations to double check. They agree very well! And are really scary!!

In the densest part of LEO (Starlink), there are closer than 1km approaches every 15 minutes. 1km sounds like a lot, but remember everything in LEO is moving at 7km PER SECOND

A plot from Thiele et al. 2025 showing average time between encounters that are closer than 1km at different altitudes in Low Earth Orbit. It's mostly in the 1 day range, except where Starlink's very dense orbital shell are, where it goes down below every 15 minutes.

Prof. Sam Lawler @sundogplanets@mastodon.social

12/11/2025, 2:16:24 PM

Public

Starlink themselves report an average of 1 collision avoidance maneuver every 2 minutes between Dec 2024-May 2025. So that's another (terrifying) double check on this calculation. https://www.scribd.com/document/883045105/SpaceX-Gen1-Gen2-Semi-Annual-Report-7-1-25?v=0.698

SpaceX Gen1-Gen2 Semi-Annual Report (7!1!25)

SpaceX submitted its semi-annual reports for Gen 1 and Gen 2 satellite constellations, detailing their commitment to sustainability and safety in satellite operations. The report highlights SpaceX's conservative approach to collision avoidance and deorbiting, emphasizing the importance of transparency and collaboration among satellite operators for space sustainability. Additionally, it addresses challenges in collision avoidance processes and the need for consistent data sharing among operators to enhance overall safety in space.

www.scribd.com · Scribd

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