camelot-forum.co.uk

This is absolutely fascinating.
The SpaceX Starlink internet satellite constellation requires many thousands of satellites to be deployed in relatively low earth orbit.
With a recent launch, it seems that a large number of those satellites never made it to orbit because of a solar storm - one of the consequences of which is that the atmosphere thickens, which created too much drag for the recently deployed satellites to be able to overcome.

Wow, given the relative frequency of solar storms and their forecasting many years ahead you would have thought someone would have raised this scenario? seems like a rooky mistake in that context, unless these satellites are only supposed to last 12 or so months before they are spent ?

Moxi

I don't think you can forecast a solar flare, they just erupt. A good description on the SpaceWeather site.

"Two days before launch a CME hit Earth's magnetic field. It was not a major space weather event. In fact, the weak impact did not at first spark any remarkable geomagnetic activity. However, as Earth passed through the CME's wake, some sputtering G1-class geomagnetic storms developed. It was one of these minor storms that caught the Starlink satellites on Feb. 4th.

Geomagnetic storms heat Earth's upper atmosphere. Diaphanous tendrils of warming air literally reached up and grabbed the Starlink satellites. According to SpaceX, onboard GPS devices detected atmospheric drag increasing "up to 50 percent higher than during previous launches."

"The Starlink team commanded the satellites into a safe-mode where they would fly edge-on (like a sheet of paper) to minimize drag," says SpaceX. "Preliminary analysis show the increased drag at the low altitudes prevented the satellites from leaving safe-mode to begin orbit raising maneuvers, and up to 40 of the satellites will reenter or already have reentered the Earth’s atmosphere."

Hi Sunrisemike,

They do attempt to forecast flares for years ahead - but its a "new" science as I understand things (a few decades in service ?) so a bit like terrestrial weather forecasting in the early years its prone to being inaccurate and have the odd surprises as you have noted.

I think what I was trying to say, badly as I only speak fluent Yorkshire, is that arranging for any satellite to sit in such a low earth orbit so as to be at risk of atmospheric expansion events should be expecting to lose some of those satellites given that we are likely to get flares more regularly than whatever the life expectancy of the satellite was?

Like designing car wheels only for dry weather when we know its going to rain at some point before the car reaches the scrappers at the end of its life, the exception being Datsuns of the 1960 and 70's which seemed to corrode away on the drive (for those of us of a certain age )

http://flarecast.eu/#:~:text=FLARECAST% ... n%20system.

Moxi

I'm sure theres a lot more to it than has been reported but I do wonder if the fuel weight for altitude manoeuvring would have been better spent on stronger electronics capable of doing their service duty at a higher altitude - unless of course the space X team only had access to the lower orbit zone in which case - unlucky.

The only positive is the satellites will not clutter orbital space as hazardous FOD I just hope theres nothing particulalry toxic that will cause issues upon burn up.

Moxi