4
$\begingroup$

I wonder what is the approach to replace let's say: 5 defective Starlink satellites, each one in a different orbit? I guess that it can't be done with just one launch as the krypton ion thrusters delta-v is low and should be used to avoid collision, orbit raising and re-entering.

$\endgroup$
4
  • 1
    $\begingroup$ I ballpark-estimated 190 m/s for a Starlink's delta-v, that gets you about 8 to 10 degrees of plane change if you blow it all at once, so yeah, they'd have to have some kind of enhancement gizmo to put each in a different plane. $\endgroup$ – uhoh Jan 28 '20 at 10:10
  • 2
    $\begingroup$ Wellcome to stackexchange. Good first question! I guess they will use some analog to this xkcd joke. As soon as a high enough number of satellites in a plane is defect they will simply replace the whole plane as most likely more will fail soon too. $\endgroup$ – Christoph Jan 28 '20 at 11:36
  • 1
    $\begingroup$ I would expect they are launched with spares in each plane, so when one fails a standby takes over. $\endgroup$ – user20636 Jan 28 '20 at 12:20
  • $\begingroup$ @JCRM is most likely correct: just as with GPS satellites, the point of having a bunch of them is so performance does not significantly degrade if a few go bad. $\endgroup$ – Carl Witthoft Jan 28 '20 at 12:40
2
$\begingroup$

There are a lot of possibilities. A few things to keep in mind.

  1. The early days of Starlink will not have guaranteed 100% uptime.
  2. Starlink requires a 40 degree above the horizon line of sight. This is actually very large, many satellites only require 10 or even 5 degrees. This means that there has to be a lot more Starlink satellites, but there might be a bit of spare capacity if you spread them out.
  3. Eventually the increase in satellite count will be more dictated on increased capacity, and not on redundancy. A few single missing satellites won't make a huge difference.

For the early days, I predict they will space out the satellites in the same plane a bit more for the short term. For the long term, they will have a few on-orbit spares, or new launches, where one of the satellites will be put in an orbit to gradually move it to the correct plane.

For later days, there will probably be some spares in the plane, so simply moving one of those around can be done, and will only take a few days. That will leave a "hole" where periodically the capacity will drop slightly, but that probably isn't a huge issue in the grand scheme of things.

$\endgroup$
2

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.