Sun Coast Amateur
Radio Club Society - blog:2025-12-23

24_hours_of_earth_s_rotation

24 hours of Earth's Rotation

I just love to watch this time laps...

coastal_flood_mapping

Coastal Flood Mapping

On December 9, the Coast Reporter ran an article detailing how new SCRD maps “show just how close critical infrastructure is to the water’s edge”.

The article didn't really explain how to navigate the maps so here's what I found:

Load the maps from here (the map's home page is here).
To declutter the information a bit, you can remove the “Inundation at Current Sea Level” layer by clicking on:
- “I want to” (top left corner)
- “Turn map layers on and off”
- “Environment” → “Coastal Flood Mapping” → “Inundation SLR Scenario”

Here are two areas we all guessed would be affected first:

Downtown Sechelt	Davis Bay

The lightest colour represents a 0.5 m sea-level rise
The medium colour represents a 1 m sea-level rise
The darkest colour represents a 2 m sea-level rise

the_crash_clock

The CRASH Clock

A group of scientists from Princeton University, UBC, and University of Regina submitted a pre-print on the arXiv, where they

[...] introduce the Collision Realization And Significant Harm (CRASH) Clock, a [Key Environmental Indicator] (KEI) that evaluates the stress on the orbital environment. (p. 5)

The idea is to:

to determine how quickly we could expect a collision [between satellites] if collision avoidance manoeuvres were to suddenly stop or if there was a severe loss in situational awareness (such as due to a major solar storm or catastrophic software issue). It is a measure, in part, of the degree to which the orbital environment is a house of cards. (p. 5)

According to their work, back in 2018 (before the mega constellation era), the CRASH clock was 121 days. Now (as of June 2025), the CRASH clock is 2.8 days. (p. 6)

According to the most recent SpaceX biannual report, Starlink satellites made 144,404 collision avoidance manoeuvres in the period between 1 Dec 2024 and 31 May 2025, averaging to 41 manoeuvres per satellite per year, or one collision avoidance manoeuvre every 1.8 minutes across the whole megaconstellation. (p. 5)