SpaceX Starlink satellites had to make 25,000 collision-avoidance maneuvers • Hacker News Board

Re: SpaceX Starlink satellites had to make 25,000 collision-avoidance maneuvers

#51

Post by dgrin91 » Fri, Jul 14, 2023, 9:47 PM UTC

axus wrote: post #19

dgrin91 wrote: post #10

Earlier quoted context omitted.

> There’s traffic in space. Is there? I mean obviously there are other satellites, but typically the framing has been that space and LEO is so big that it doesn't matter. That even with all the other satellites you typically don't need any sort of course correction except in very rare circumstances. Isn't the better analogy 'I used to never need to do any swerving at all on my morning commute, but now I need to do it…

There's a space object and debris tracking visualization at http://astria.tacc.utexas.edu/AstriaGraph/ You can filter to "Low Earth Orbit" and play at 100x speed to get an idea of how things are moving around. There's a lot of intersecting paths, a lot of them Starlink satellite trains.

These visualizations are great to give you a basic sense of whats going on up there, but they do not represent any sort of realistic scale. If they did then the visualization would be boring because everything would be WAY too small.

Also it is stuck with a relatively 2D format. Are the satellites really intersecting or is there 10km of vertical distance between them? Its hard to tell with these forms of visualization.

Re: SpaceX Starlink satellites had to make 25,000 collision-avoidance maneuvers

#52

Post by yreg » Sat, Jul 15, 2023, 2:37 AM UTC

Stephen304 wrote: post #48

yreg wrote: post #42

Earlier quoted context omitted.

>by having such a lower risk tolerance What do you mean by this? The article says that NASA makes an avoidance maneuver when the chance of crash is over 1 : 10 000, SpaceX does it when it's over 1 : 100 000.

They seem to mean exactly what you quoted - a lower risk tolerance means they tolerate less risk, meaning they are more cautious. Doing an avoidance maneuver if the risk exceeds 1/100K instead of 1/10K is being more cautious because 1/100K is a lower threshold than 1/10K.

Ah, you are right of course.

Re: SpaceX Starlink satellites had to make 25,000 collision-avoidance maneuvers

#53

Post by wkat4242 » Sat, Jul 15, 2023, 3:22 AM UTC

How do these sats even know objects are coming? The relative velocity could be tens of kilometers per second. Meaning any optical method would direct it way too late.

And I don't think these are big enough to have serious radars on board capable of seeing hundreds of kilometers away. That just leaves ground control I guess?