Thread | Brutkey

Starlink will lower the orbit of all (~4,400) satellites from 550 km to 480 km during 2026.

Reasons are described in the tweet below by VP of engg.

We presume they have FCC approval.

Qs:
1. Why now? Solar minimum is 5-6 years away.
2. Will they move back to using the 550 km orbit at the next solar maximum, 12 years from now?
3. Is Starlink responsible for some of that debris at 550 km?
4. Are there other reasons for this change in orbit?

Does this all make sense?
@sundogplanets@mastodon.social
1/n

Tweet by Michael Nicolls @michaelnicollsx, VP of Starlink Engineering

Starlink is beginning a significant reconfiguration of its satellite constellation focused on increasing space safety. We are lowering all @Starlink satellites orbiting at ~550 km to ~480 km (~4400 satellites) over the course of 2026. The shell lowering is being tightly coordinated with other operators, regulators, and USSPACECOM.

Lowering the satellites results in condensing Starlink orbits, and will increase space safety in several ways. As solar mininum approaches, atmospheric density decreases which means the ballistic decay time at any given altitude increases - lowering will mean a >80% reduction in ballistic decay time in solar minimum, or 4+ years reduced to a few months. Correspondingly, the number of debris objects and planned satellite constellations is significantly lower below 500 km, reducing the aggregate likelihood of collision.

Starlink satellites have extremely high reliability, with only 2 dead satellites in its fleet of over 9000 operational satellites. Nevertheless, if a satellite does fail on orbit, we want it to deorbit as quickly as possible. These actions will further improve the safety of the constellation, particularly with difficult to control risks such as uncoordinated maneuvers and launches by other satellite operators.

Prof. Sam Lawler
@sundogplanets@mastodon.social

@AkaSci@fosstodon.org Starlink asked for 15,000 more satellites at 350km altitude. Not at all clear to me if this is in ADDITION to the 42,000 they already have permission for, or how those other orbits will fit in.

They will be brighter, faster, and fitting into a smaller orbital area. They will stick around for less time after they start crashing, but will burn up in the atmosphere/hit the ground faster too. Not good.