Stargaze: SpaceX's Space Situational Awareness System
131 points
11 hours ago
| 9 comments
| starlink.com
| HN
neom
37 minutes ago
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I was kinda hoping the collision risk stuff might be what stops the sky quickly getting totally polluted. This is cool but... I presume just enables more and more and more density.
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pjscott
8 hours ago
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Honestly, these two paragraphs are one of the most compelling things they could possibly say in a press release:

> Stargaze already has a proven track record in its utility for space safety. In late 2025, a Starlink satellite encountered a conjunction with a third-party satellite that was performing maneuvers, but whose operator was not sharing ephemeris. Until five hours before the conjunction, the close approach was anticipated to be ~9,000 meters—considered a safe miss-distance with zero probability of collision. With just five hours to go, the third-party satellite performed a maneuver which changed its trajectory and collapsed the anticipated miss distance to just ~60 meters. Stargaze quickly detected this maneuver and published an updated trajectory to the screening platform, generating new CDMs which were immediately distributed to relevant satellites. Ultimately, the Starlink satellite was able to react within an hour of the maneuver being detected, planning an avoidance maneuver to reduce collision risk back down to zero.

> With so little time to react, this would not have been possible by relying on legacy radar systems or high-latency conjunction screening processes. If observations of the third-party satellite were less frequent, conjunction screening took longer, or the reaction required human approval, such an event might not have been successfully mitigated.

Looks like a non-trivial upgrade to previous systems, and they're making Stargaze's data available to other satellite operators free of charge. Nice!

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c22
2 hours ago
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It will be interesting when multiple parties are using these systems and still failing to communicate out of band. Like trying to pass someone in a hallway who keeps trying to make the same course correction as you until you both make eye contact and come to a real agreement.
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close04
1 hour ago
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> they're making Stargaze's data available to other satellite operators free of charge

With so many Starlink satellites odds are that one false move on anyone's part ends up in an incident involving them. Sharing this data makes the field safer for everyone, and Starlink gets to steer clear of any bad news titles.

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Coeur
3 hours ago
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Now I would really love to know who the other operator was.
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NitpickLawyer
2 hours ago
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> In a statement posted on social media late Dec. 12, Michael Nicolls, vice president of Starlink engineering at SpaceX, said a satellite launched on a Kinetica-1 rocket from China two days earlier passed within 200 meters of a Starlink satellite.

> CAS Space, the Chinese company that operates the Kinetica-1 rocket, said in a response that it was looking into the incident and that its missions “select their launch windows using the ground-based space awareness system to avoid collisions with known satellites/debris.” The company later said the close approach occurred nearly 48 hours after payload separation, long after its responsibilities for the launch had ended.

> The satellite from the Chinese launch has yet to be identified and is listed only as “Object J” with the NORAD identification number 67001 in the Space-Track database. The launch included six satellites for Chinese companies and organizations, as well as science and educational satellites from Egypt, Nepal and the United Arab Emirates.

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ge96
1 hour ago
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> 48 hours after payload separation, long after its responsibilities for the launch had ended

This is funny, the way things are just discarded in space, not our problem anymore vs. deorbit

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panzagl
30 minutes ago
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I think this is more that the offending satellite was at that point the responsibility of the satellite operator, not the launch operator.
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NitpickLawyer
30 minutes ago
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I think they are saying "this is not on us, this is on the sat operator". Which may or may not be true, who knows.
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jacquesm
3 hours ago
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And what the goal of that maneuver was.
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phkahler
17 minutes ago
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It seems like it deliberately came close to the Starlink sat, but the "why" is still a good question.
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bell-cot
8 minutes ago
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A test SpaceX's awareness & response would be ample reason.
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ge96
1 hour ago
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Cause problems and deny it
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thatjoeoverthr
1 hour ago
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Kessler problems require Kessler solutions
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Hextinium
9 hours ago
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Seems like a generally good idea, the satellites already need to use star trackers, they need an almanac of what should be there so deviations need to be tracked.

I can entirely see the military perspective though, this is almost a direct challenge for any adversary that any maneuver you perform, we will know about it.

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reed1234
8 hours ago
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The Space Force already tracks satellites (and debris). I imagine this is more of an improvement for small debris such as bolts, etc.
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sfblah
7 hours ago
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It's not.
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pjscott
7 hours ago
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If you're familiar with the technical specs, I'd be interested in hearing what size of objects the star trackers can sense and at what range. In theory the fancier star trackers can see objects around 10 cm diameter hundreds of kilometers away, without needing to worry about a pesky atmosphere [1], but I don't know how sensitive the sensors on Starlink's current generation satellites are, and this web site isn't saying.

They're mostly touting the improvement in latency over existing tracking, from delays measured in hours to ones measured in minutes. Which is very nice, of course, but the lack of other technical detail is mildly frustrating.

[1] https://www.mit.edu/~hamsa/pubs/ShtofenmakherBalakrishnan-IA...

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jcims
43 minutes ago
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Note from analysis in the paper: (CST = Commercial Star Tracker, for which they model several common ones flown on satellites)

>From Fig. 1, it is clear that many typical CSTs can be used to detect debris with characteristic length less than 10 cm at distances as far as roughly 50 km. These same sensors have the potential to detect debris as small as 1 cm in diameter as far as 5 km away. Even space-limited CubeSats using nanosatellite-class CSTs can detect 10-cm-class debris at roughly 25 km away or 1-cm-class debris at a distance of 2.5 km. Higher-performing imagers like the MOST telescope can further characterize orbital debris of 10 cm diameter as far as 400 km away or be used to characterize orbital debris smaller than 1 cm at ranges not exceeding 40 km.

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mikkupikku
6 hours ago
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NASA tracks debris 10cm or larger. They also detect and statistically estimate debris as small as 3mm in LEO.

This is my source, from 2021 fwiw: https://oig.nasa.gov/office-of-inspector-general-oig/ig-21-0...

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wolvoleo
2 hours ago
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10cm is huge, that could even be a functioning 1U cubesat.
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pjscott
6 hours ago
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So it looks to be just the latency improvement that's noteworthy, then. Thank you!
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sfblah
5 hours ago
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Yes. Sorry for the brief answer. Too bad I got downvoted. There's no size improvement.
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w10-1
4 hours ago
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This seems necessary and desirable, but pretty much a government function. I can't see how simple good-faith cooperation prevents abuse.

Possible abuses:

(1) Use the information to actually interfere or collide with satellites

(2) Use the information to track secret satellites by excluding traces from non-secret ones

(3) Free riders gaining secondary access without providing data

(4) Use access to this when traffic is more contended to enforce hegemony

(5) Anti-competitive coordination under the rubric of cooperation

And while the system might be helpful under ordinary peacetime conditions, will it make a war more or less destructive?

It's silly that NASA is planning for Mars and the moon but hasn't already solved this coordination problem on a world scale.

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notahacker
31 minutes ago
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NASA already provides publicly accessible tracking data. They don't have 30,000 star trackers in orbit though, whereas the world's largest satellite constellation does and therefore has a lot more data points.
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nlitened
4 hours ago
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As far as I understand, bad faith actors already have wide possibilities for disruption and abuse. This system allows for better good-faith coordination for mutual benefit.
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user3939382
1 hour ago
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DARPA from long back had a project for tracking space debris related to this. I have an impossibility proof and some other math after many years of thinking about this problem which proves that what they really need (and have explicitly asked for) is impossible but also how theoretically close to it we could get. Hoping to publish soon but working on other things.
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01HNNWZ0MV43FF
5 hours ago
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Damn it. I wanted to use that name
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wtcactus
7 hours ago
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"To maximize safety for all satellites in space, SpaceX will be making Stargaze conjunction data available to all operators, free of charge, via its space-traffic management platform."

Many people don't still realize it, but the problem of low orbit debris is only getting worse. So, this is a really nice gesture. Thank you, Elon Musk.

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iNic
5 hours ago
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The one advantage of monopolies is that they tend the commons.
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uyzstvqs
5 hours ago
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You're free to start your own space exploration company.
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dmd
45 minutes ago
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Er, no, you're not. That's the big problem with monopolies that execute regulatory capture.
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lionkor
7 hours ago
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It sounds like a hook, like "don't like all the space debris? use our management platform" and then it'll suddenly start costing money
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bigfatkitten
5 hours ago
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SpaceX has a very, very large financial interest in avoiding collisions. Providing this service helps ensure that.
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wtcactus
4 hours ago
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Several governments have an even bigger interest in avoiding these collisions, so, these systems should have existed for decades now.

But, you can always trust the government to spend 10x more to do 10x worst...

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notahacker
27 minutes ago
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The US already provides publicly accessible conjunction avoidance data based on data points they have. They don't have the same number of satellites in the sky to make real time observations in as many different directions though.
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mikkupikku
3 hours ago
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> so, these systems should have existed for decades now.

Dubious. Perhaps if Congress could be persuaded to invest in tons of radio telescopes / radars, positioned all around the world, but good luck with that. The space-based approach used by SpaceX is something that presently only SpaceX is equipped to implement. Tracking star conjunctions only gives you high quality data on space debris / satellite maneuvers if you have a huge net of star trackers in orbit, and that's something which only SpaceX has been able to do.

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drivingmenuts
9 hours ago
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Who knew that Big Brother would name himself after a 1990s movie about a completely different premise?
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