Stargaze: SpaceX's Space Situational Awareness System | Hacker News Reader

Stargaze: SpaceX's Space Situational Awareness System

starlink.com

187 pointshnburnsy108 comments

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!

Now I would really love to know who the other operator was.

And what the goal of that maneuver was.

Cause problems and deny it

It seems like it deliberately came close to the Starlink sat, but the "why" is still a good question.

A test of SpaceX's awareness & response would be ample reason.

If so, SpaceX's longer term response being "here's our SSA data for everyone and here's how we source it" is a good one for all parties involved (even more so for SpaceX and govt customers they share it with if they have other capabilities...)

Speculation:

SpaceX has considerably better data than what they disclose, and offer free of charge.

The USSF enjoys full access to that better data, for $[TOP_SECRET]/month.

Well we already know Starshield (the military version) has specialist space domain awareness capabilities that aren't being shared, and it's entirely plausible that data from regular Starlink sensors/receivers (other than the disclosed star trackers) can be fused into something useful by SpaceX and/or the Space Force.

Weapons test springs to mind, or as a sibling comment suggested a test of Starlink response capabilities.

How confident are we the intent was nefarious? Do you ever see accidental near-misses with this type of flight profile?

The system exists- ergo, people in the know are concerned about accidental collisions.

Alternative: the system exists, so people in the know may well have done proper risk assessment and may have identified multiple reasons that could result in a collision. Some of those reasons are accidental, some are not.

> 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.

> 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

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.

unless the sat operator is sueing for a refund because they were put in the wrong orbit... its the sat operator.

I think this is more that the offending satellite was at that point the responsibility of the satellite operator, not the launch operator.

If you get hit by a car 5 minutes after you get let off at a bus stop it isn't the bus drivers fault.

Nah, in this case the driver is the person who gets off and goes and bumps into another person.

Yeah while I didn't directly mention it, I'm referring to stages being discarded in space by a specific party

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.

When you're SpaceX and building this[1], others aren't going to try too hard to avoid your satellites..

[1] https://wikipedia.org/wiki/Golden_Dome_(missile_defense_syst...

> still failing to communicate out of band.

I don't understand countries or operators that do this.

There's no secrets about hardware position and orbit. Even amateur astronomers can track spacecraft.

There's no benefit to trashing orbit from failure to coordinate and cooperate. Any collision in LEO will deny it to everyone for several years.

So who is being insular and why is it to their advantage?

> 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.

> react within an hour of the maneuver being detected

I'm curious at what steps were involved took an hour. Running the calculations should be quick (computers are fast), as is transmitting commands.

This sounds like there's human in the loop that had to make decisions.

Orbital mechanics can be somewhat counterintuitive.

If you want to change the altitude of your orbit at a certain place, the most efficient place for that is generally when you're on the other side of the planet from that place.

In low earth orbit it takes about 90 minutes to go around the planet, so a small nudge 45 minutes before the potential intercept is going to be vastly more efficient than a big shove when the collision is 5 minutes away.

Starlink uses high efficiency ion thrusters so it has to do small nudges anyway..

So I would not be surprised if most of that hour is spent waiting for the right time to fire the thrusters.

Maybe I misinterpreted the statement - I thought it was talking about the time from detection to sending the command to the satellite, not the time until the satellite actually took action.

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.

The Space Force already tracks satellites (and debris). I imagine this is more of an improvement for small debris such as bolts, etc.

It's not.

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...

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...

So it looks to be just the latency improvement that's noteworthy, then. Thank you!

Yes. Sorry for the brief answer. Too bad I got downvoted. There's no size improvement.

It got downvoted because it had no info about why you claimed there was no improvement.

SpaceX wouldn’t waste money developing a system that had no improvement over what space force already offers.

They would if they could bilk more taxpayer money for it.

Maybe coverage, too?

10cm is huge, that could even be a functioning 1U cubesat.

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.

Kessler problems require Kessler solutions

There's an interesting podcast covering space situational awareness from RUSI (Royal United Services Institute, UK). Link: https://podcasts.apple.com/gb/podcast/eyes-in-orbit-space-si...

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.

Didn't the Pentagon give SpaceX a bunch of money a while back? Any chance this was developed alongside, or as a component of, military applications?

Getting 30,000 new eyes in the sky actively monitoring objects in orbit seems pretty appealing if that's your theater...

How does this compare in scope and quality to traditional tracking networks (ground or space based)?

Nah sounds like regular starlink they have 10,000 of them

The Pentagon has been giving SpaceX a bunch of money for over a decade

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.

Does anyone know what the "30,000 star trackers" are? There are about that many satellites in orbit, so does this mean almost everyone is contributing data?

I think it just means each starlink satellite has multiple star trackers. Probably pointed in different directions so that if one is blinded by the sun the others can still see the stars.

Quite common for a sat to have 3 star trackers so it is possible just starlinks

At some point in the future, will there be wars fought in LEO? Seems like a cold war already.

I believe the US and China (and Russia according to the Wendover video [1]) already have anti-satellite weapons to be used in a conflict, but they aren't like "blow this up" because of space debris. I'm not exactly sure how they work, but they aren't what we expect with terrestrial weapons.

1: https://www.youtube.com/watch?v=V0DmliiUFHk

Didnt russia cause a lot of debris due to one of their tests and endanger the ISS crew ?

Yeah I just watched my own video and was surprised to see exactly that. Because I remember reading somewhere else years ago that an ideal anti-satellite weapon would either de-orbit a satellite (like bumping it off orbit so it burns up) or use some kind of net/capture to push it off orbit, rather than blow it up.

Now this is going to have to be a rabbit hole for me (and some AI) this weekend.

Their test was in a low-ish orbit so most of the debris is gone now.

I haven't looked at stats lately but I'd guess the #1 source of debris in space right now is still the Chinese ASAT test which threw a bunch of crap into Medium Earth Orbit. Before that, the main source of debris was leaking coolant from some nuclear reactors the Soviet sent up

This article is a short history of anti-satellite weapons, discussing who has demonstrated their capability: https://www.raf.mod.uk/what-we-do/centre-for-air-and-space-p...

I'm sure I read a more recent account of a satellite moving another satellite around in order to degrade its orbit, but I can only find this 2022 instance: https://www.twz.com/44054/a-chinese-satellite-just-grappled-...

What happens if you have a satellite that takes images of earth and it gets hit with a power beam of light that destroys the sensor so you get no more images of earth? Is that satellite just as dead to you as if it were rapidly disassembled? What happens if your satellite was heated for extended time beyond what it was designed to do? Is that satellite just as dead to you?

Isn't this just a twist on celestial navigation?

Back in 2020 articles came out on how New Horizons is now so far out that it sees stars differently from its perspective than how we see them on earth.

https://www.space.com/nasa-new-horizons-star-shift-parallax-...

Damn it. I wanted to use that name

"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.

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

SpaceX has a very, very large financial interest in avoiding collisions. Providing this service helps ensure that.

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...

> 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.

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.

The one advantage of monopolies is that they tend the commons.

You're free to start your own space exploration company.

Er, no, you're not. That's the big problem with monopolies that execute regulatory capture.

Sure you are. SpaceX did exactly this and went against the well-connected monopoly at the time (ULA, a consortium of defense contractors) and beat it.

Nobody said it would be easy though.

You too can start your own space exploration company if you are lucky enough to somehow obtain capital and your luck compounds sufficiently from that capital.

That luck is out of grasp of the vast majority of the population. It isn't a matter of effort, but mostly luck. Playing the lottery is not a realistic strategy to put forth from a monopoly competition perspective. 90% of startups fail, for example. They worked hard, but were unlucky.

Spacex creating solutions to the problems they caused.. great

That seems... responsible? Maybe you meant "great" literally. In that case, I agree. Good job SpaceX.

all this tech is nice and dandy n' all but the guy in charge of it is so distasteful that id rather live in a cave with stone tools than rely on any of it.

I wonder what you have to say about our new generation fertilizers and vaccines.

I was just having this discussion in the other thread where people were blatantly lying about Tesla because they hate Elon Musk. Hate him all you want, but his companies are truly successful.

I was just thinking about that the other day while relaxing in my Hyperloop pod from Los Angeles to San Francisco. I was reminiscing about how I'd avoided all the traffic in LA by using the Boring Company's tunnels in my second-generation Tesla Roadster. I'd been in LA for a conference about the hugely successful Starship space launch system, which has revolutionized cost to orbit with fully reusable second stages. When I got to San Francisco, I hopped in a Tesla fully self-driving robotaxi, and when I got home, my Optimus robot served me tea after I instructed it to do so using my Neuralink probe. I then sent a video voicemail to my parents, who live in a city of 1 million people on Mars, which has recently been terraformed. I flipped on CNN and was gratified to see that, for the first time in 25 years, the US government was operating at a surplus, thanks to the $2T of annual savings delivered by DOGE.

Starship is iterating fast and flying in another 5 weeks. Boring company is executing slowly but steadily, the Vegas tunnel is progressing. Unsupervised robotaxis has started in Austin. Optimus started a few years ago only, it is disingenuous to expect it to be available immediately. Neuralink has 18 patients now. Mars is happening, Elon never promised it will be possible this decade.

Your comment makes it seem that Elon's companies have done nothing. I know you are being disingenuous, but I am trying my luck to respond.

> “Starship is going to Mars at the end of 2026.”

https://www.futura-sciences.com/en/elon-musk-promises-a-trip...

> New video evidence shows that Tesla’s supposedly “unsupervised” Robotaxis in Austin are being closely followed by black Tesla trailing cars with safety monitors inside. Tesla didn’t remove the safety monitors – it just moved them to a different vehicle.

https://electrek.co/2026/01/22/tesla-starts-robotaxi-rides-w...

Lol. So a fully self driving car with a following car is not impressive? Elon over promised, no doubt. But don't tell me their tech is not amazing. Pure vision general purpose autonomy. It's going to be a game changer. It could be late but inevitable.

Remember when it was supervised FSD? They have come a long way.

Consider this: What tech might we have if the entire world economy weren't infested with termites like Musk who lie continuously to pull in investment that could have gone elsewhere?

What are you talking about? Please read Tesla stats.

Tesla's high-priced sports cars are the wrong product. The right product is a low-cost car like the BYD cars that aren't legally allowed to be sold in the US. The US has probably already lost the EV war, and Tesla is principally responsible. Everything Musk touches turns to garbage.

I'm sure the Midas touch of Ford and GM will fix it.

We can both be correct. I'm not saying he's done nothing. I'm saying he lies, A LOT.

Microsoft Bob, Google Inbox and Plus

Good-faith products that launched, were bad ideas, and failed. Musk is absolutely unique in world history for the sheer number of fake products he's used to garner investment (mostly from the government if we're being honest) and then line his own pockets. If Trump is Darth Vader, Musk is The Emperor.

This is cope sorry.

No honesty in your mostly.

Lol. The million Teslas and Starlink satellites are fake? At least be subtle to lend some credence to your statement.

better stay out of biography books

Would this sort of operational prowess be possible if it weren't for Musk? Will the future be kind and reflect back in the hindsight when Musk dies?

> Will the future be kind and reflect back in the hindsight when Musk dies?

id hazard a guess and say it will, people love to hero worship but he's his own biggest fan. nothing he built wasnt done before in some way. if im being generous id say hes a good integrator of tech, which in itself isnt such a bad thing, if thats all it was.

Uh huh, i get 300mbit burst 200mbit sustained download and 20mbit sustained upload, midday, from a forest in the dead center of louisiana. oh and with a consistent 59ms ping to our DC on the east coast (not aws), 24/7, over millions of pings.

can you tell me what other provider is doing that? for $120 a month? Were you thinking of hughesnet? because that was ADSL speeds with 20 times the latency. seriously, upwards of 1000ms round trip time.

yes, a century and a quarter ago there were electric cars. that went 15 units per hour for 20 minutes or whatever. Then Saturn EV-1 by GM was lease only, i wanted to own one and was unable to. what happened between the EV-1 and Tesla that made it to mass market? was there a fEV that i am not aware of that had sales numbers similar to Tesla's?

is it about the flamethrower? those already existed. So did tunnels. I guess you got me.

too bad all this is buried.

you missed my point but im glad your enjoying those things

I think it should. Hate it or not he has a proven ability to create environments where people thrive and want to work the hardest they ever have. Moreover, an ability to understand how much money is required to build something alongside the daring to actually try it. Again, I wish he never got into politics, but generally he knows how to build things people want, and uniquely wants to try.

There it is... the usual ELON MUSK BAD.

I usually don't comment on politically charged topics (because I don't shit where I eat), but the amount of champagne socialists around here is borderline Reddit and its negatively influencing the discoverability of the news I'm coming here to see.

Like... SpaceX is the world leader in rocket and satellite tech. This site is supposed to be about tech. Not to mention that the article itself is really interesting. Yet you come in here and dump your musky load like it's a public toilet. What the hell is wrong with you.

virtue signalling. in-band and out-of-band.

Casey Handmer was speculating that they could use these Starlink images to detect Near-Earth Asteroids using star occultations:

https://x.com/CJHandmer/status/2017124903057838374

You basically have thousands of cameras taking constant images of the sky. If you could upgrade the cameras, you could deploy a continuous all-sky astronomical survey as a by-product.

Rough estimate on the cost delta for the camera upgrades?

No idea--but he thinks the asteroid detection could be done even without an upgrade, assuming current cameras can see down to magnitude 7 (which is not that faint--human eye should be able to see down to 7 or 8 in space).

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

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.

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.

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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