ISS orbit watch - 4km boost applied over the last few days
(whatever)Following
this post about the ISS falling, I started watching its orbit.
First thing of note - the ISS has a much
higher LOWER atmospheric drag value in its orbital elements than with other craft at that altitude,
like 2-4 times higher by one order of magnitude.
That can be due to having a large cross-section with hollow volume inside, though. With LESS drag, it should be EASIER to keep in orbit.
At the time (2024-12-18) its lowest altitude was 409.74 km; the projected descent was around 0.15 daily, which is indeed around 4.5 km monthly, close to the 5 about which "FEMA"-anon was doomsaying. Other craft drag too, though - anything as low as 400 is going to need tangential propulsion to keep speed up.
Since then (5 days ago) the ISS has been given a 4 km RADIAL boost to raise its orbit, now with a low of 413.20. This has delayed its timing and placed it some 10 degrees off its previous point above Earth, unlike other craft for which the older elements could still be used now.
Will keep watching and comparing it, and maybe try to get older data for comparison. If radial boosts are a regular occurrence then something's off, it should be a gradual tangential push to counter the drag.
EDIT: Misread the drag term, ISS is actually smoother and having to boost it upwards is sort of bad.
