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Comment by dylan604 | Hacker News Reader

“No one thought of this,” she said. “We didn’t think of it. The astronomy community didn’t think of it.”

I really have trouble believing that nobody mentioned adding thousands of satellites would go unnoticed. It is damn near impossible to take any image of the night sky without having a satellite streak through the frame. I have plenty of images with multiple satellites visible at the same time. In wide angle timelapse sequences, they are just small dots that move against the natural movement of the stars. In longer lenses/telescopes, they appear as long straight lines totally ruining the image.

The first time I heard about thousands more of lower altitude satellites, my first thought was about this very thing. We had already had the discussions from the giant disco ball that was launched. It was planned to be short lived, but it caused quite the stir. Saying people at SpaceX didn't think about it is one thing, but to claim nobody in the astronomy community didn't is hard to take. Maybe they didn't have any way to voice those thoughts in a way that SpaceX could hear.

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Yeah even the wikipedia page mentions the astronomers' concerns

https://en.wikipedia.org/wiki/Starlink_(satellite_constellat...

btw the amount of satellites is staggering and this is just a tiny batch: https://www.youtube.com/watch?v=gRz3988El7Q&t=116s (Warning: hilarious commenter)

> even the wikipedia page mentions the astronomers' concerns

Note, this section was added June 03 2019.

https://en.wikipedia.org/w/index.php?title=Starlink_(satelli...

yep. the referenced articles are from this summer. still before the launches

60 satellites were launched on 24 may 2019. It looks like all the articles are after that, in response to people seeing the satellites in the sky.

Here's a 1999 article, well before the announcement of Starlink, talking about the increasing problems of trails spoiling deep sky observations--- https://www.sciencedirect.com/science/article/pii/S027311779...

> From Table 1 it is clear that since 1985 the annual mean number of trails has risen from 2.5 to 2.9 in a 60 minute exposure, an increase of 16%; the number of spacecraft on orbit has increased by 39% in the same period. Since the trail rate data comes from a set of plates not selected for time of night of exposure, the trail rate is averaged over an entire night. Since trailing is most frequent in the two hours after sunset and before sunrise, it would be expected that the trail rate would not increase as rapidly as the spacecraft population. However, the trend is such that it supports the view that plate trailing is caused by spacecraft and large debris and not by debris more generally. The figures suggest that the satellite population is doubling approximately every 14 years at present launch rates. The concern of the astronomical community is that due to the advent of large satellite constellations such as IRIDIUM and, further in the future, a TELEDESIC network, there will be a sudden increase in the numbers of satellites capable of causing trailing. The time available to find a solution is thereby reduced.

It even foresees SpaceX's "solution" that they are trialing:

> The Space Agencies could also assist by reducing satellite albedos.

It's also discussed in similar terms in "Adverse Environmental Effects on Astronomy", D. McNally, 1992.

You can find early 2000's complaints about Iridium-spoiled optical observations.

You can find late 1960's papers analyzing the impact of satellites on optical astronomy... that point to exactly where we are now.

It's hardly a "surprise to the optical astronomy community." If there's any surprise, it's that people are actually willing to listen to their concerns.

The original assumption, as far as I'm aware, was that Starlink being in such a low orbit wouldn't have these issues that previous satellites had.

That's a bit of a strange assumption. Height doesn't have too great of an impact, other than reaching eclipse from solar illumination a little earlier. Given that Iridium has been a nuisance and they're at 780km, versus Starlink at 550km and 1150km...

A quote from a user above who worked for both SpaceX and the astronomy community:

"Now, that being said, even I was confused why this would cause a problem. The satellites are in low earth orbit, so low that they won't be able to reflect the sunlight, since they are in earth's shadow. Only during twilight and dawn will satellites be in the right position to reflect the sunlight back to the ground off of some panel.

Now, these are not prime observing hours for many people, since it is still not as dark as it could be. So most people point into the darkest parts of the sky (up) rather than at parts where there is still twilight (like nearer the horizon).

But for some types of observations, like near earth asteroids, you want to point into the evening sky to look for them, since that is one of the places you want to look, and the sky conditions should be good enough. In these pictures you'll get streaks of light as the satellites pass through."

I think the issue is more that no one has previously been launching constellations of literally thousands of satellites.

It's just not a thing that seemed like it would actually happen. I can very much imagine that it didn't get a lot of attention until they actually started going up.

Yes, it might be that the astronomer community didn't expect Starlink to actually happen. A lot of people still haven't learned that SpaceX isn't just hyping things up.

it remains an experiment; if the network test proves useful, they ll have to mitigate this issue somehow. perhaps also make the satellites smaller

They've now launched 120 satellites (there's been 2 launches of 60 satellites). The test has already proved successful. They're heading on to production now.

Off topic: I mentioned to someone at StarLink the idea of equipping their gear to perform global RF interferometry, will let you know if it turns into something!

That's awesome!

(Also, why do I get a feeling the two of us talked about using satellite constellations and interferometry on HN before?)

We did! That’s what caused me to inquire when the opportunity presented itself.

Right! I found it: https://news.ycombinator.com/item?id=19188205.

Thanks for remembering!

No need to thank me, was your idea!

That's not a new idea, and it's a lot harder than it looks.

It would be awesome if Starlink would donate bandwidth for the Greenland and South Pole EHT telescopes. Right now there's no "first look" capability for them.

Asking is free. I don’t mind making a hundred asks and looking silly if one turns out to be helpful.

If I have the opportunity, I’ll mention your suggestion.

Software should be able to account for this. If photoshop can remove people from photos, why can't astronomy software remove satellites? Orbit is already pretty cluttered and we can't remove much that gets stuck up there already.

Software can make a picture look pretty, but it has very limited use when you are fighting against the limits of information theory. You want an actual new measurement, not a guess of what a reasonable measurement would look like based on past measurements.

This isn't just about astrophotography, this has to do with real science too. Remember, most science work is already on a tight budget and now they will have to waste some of that budget sorting through the added visual clutter.

It's like with nature on earth, tech pollutes things. It's not really anything new.

its literally a new additional problem which is why its being discussed

Yes, and SpaceX seems to be actively downplaying that fact.

>. “We want to make sure we do the right thing to make sure little kids can look through their telescope,” she said. “Astronomy is one of the few things that gets little kids excited about space.”

since starlinks may change positions autonomously it's impossible to predict their positions. and they are so damn many

You don't need a position prediction to remove an anomaly.

Actually, you kind of do, because how do you know it's an anomaly and not something you want to observe? Especially if it's just occluding things in its path, and you can't see it. It's really helpful to know where everything is.

Optical signature.

Starlink satellites are too small to do much orbital maneuvering. They only carry a small supply of krypton gas for their station keeping thrusters.

They have enough propellant to change their orbital height by quite a lot, more than the typical satellite (other than GTO-to-GEO thrusters.)

OTOH you can just ask SpaceX or the Air Force where they have been in the past, SpaceX uses GPS and the Air Force radar is accurate enough for knowing where they were.

If the astronomer community requested it, I'm sure spacex would give them a real-time (or even a few minutes ahead of time) feed of satellite positions accurate to less than a pixel on these telescopes.

Yes, I’m an astronomer and I can tell you this SpaceX statement is pure BS. The astronomy community absolutely thought of this before any of these satellites were launched. I’ve personally talked about it at public outreach events (and it was members of the public who brought it up) and topic has definitely come up at professional meetings...but there is just a general feeling of powerlessness, both from the point of how do you fight a company like SpaceX and a charlatan like Musk, and also from the point of many members of the public don’t care.

I also know a lot of people directly involved in SSA and all of them are very concerned with how much these new constellations are going to increase the risk of collisions, and they all think it’s completely irresponsible when the SpaceX cultists just dismiss the concerns with, “space is a big place,” or, “they’ll deorbit in 20 years or so.”

It's very unlikely that SpaceX, who has to be concerned about space debris every time they launch, didn't think about the collision risk while they were designing their satellite system.

In fact they petitioned the FCC(?) to lower the constellation's altitude for the very reason that, in the case of a malfunction, the satellite's would orbit would degrade more quickly. A carefully tracked constellation of satellites would be much easier to avoid than the random chunks of shrapnel left behind by other mishaps.

EDIT: a few typos

I think they lowered the orbit because Starlink latency was/is not competitive.

It can’t be both?

Lowering orbit doesn't substantially reduce latency, building more satellites does.

compared to geostationary sats, starlinks are 1/30 of the distance, and thus 1/30 of the latency

It makes a difference there, sure, but SpaceX lowered orbits from 1,150 to 550km. Half the latency, but only by about as much as traffic between LA to SF incurs.

I was a bit wrong in my initial estimate. More satellites can't improve latency by much once they get dense enough, and it looks like Starlink has enough such that the altitude would be on the same scale as distance. Still doesn't matter for the typical home user. Like, I get 21 ms ping to servers in my local city.

> Still doesn't matter for the typical home user.

One very important market they're going after is global arbitrageurs.

The funny part is that by providing low latency service to them, they are (hopefully) going to be able to fund SpaceX longer to build rockets to get human colonies off-planet.

It’s almost like a Gibson or Stephenson novel.

Do you have any evidence of this? I work in algorithmic trading/finance and I'm relatively certain that this isn't true.

> Do you have any evidence of this?

My only evidence is a very basic evaluation of their publicly stated capabilities.

> I work in algorithmic trading/finance and I'm relatively certain that this isn't true.

It sounds like you have a much better informed opinion than I do.

With my limited knowledge, I see no reason why SpaceX wouldn't aggressively go after that market, but like I said, my knowledge is limited.

> Still doesn't matter for the typical home user.

550km vs 1,150km might not matter, but it matters a ton vs 40,000km. Even without the bandwidth limits, I wouldn't be able to use geostationary internet for my normal usage.

Starlink has been LEO since it was first announced, so how bad geostationary internet may be is not relevant to the discussion about why SpaceX lowered the altitude.

right i didn’t know that

They didn't lower it from geostationary, so this is--while correct--irrelevant.

Building more satellites doesn't reduce latency. Are you referring to the ISL?

Having more satellites lets you communicate in a straighter line. Lower altitude lets you hug the Earth more closely. Higher altitude lets you see more neighbors. I'd wager the low altitude satellites are for last mile communication moreso than global linkage. I mean, otherwise they'd have no use for the higher altitude ones? An optimal low latency link around the planet would mostly alternate low-high-low-high-low in sequence, if there aren't enough low altitude nodes to use them exclusively. But maybe you could crush this argument by doing the actual math in this case.

You are referring to the ISL in these satellites, that are not in the first batch, nor are there any plans to change that soon from what I've seen. So without the ISL, their latency is certainly not lower by adding more satellites. The difference in latency from different altitudes LEO is negligible.

Adding more ground stations and building more satellites does reduce latency, because there will be a satellite closer to "halfway between" you and a ground station, which defines the shortest possible path.

If there is just one (non-stationary) satellite in your sky, the geometry is probably pretty crummy, so light-speed delay is greater. Also, link budget is worse, so probably data rate is lower too.

Yes, once you have a ton of satellites, adding more doesn't improve latency much.

I was under the impression that Starlink latency is actually very competitive with terrestrial fiber. Why do you say it wasn't or isn't? Everything I find suggest Starlink will have low latency.

For most usages yes. For gaming though it's right on the edge: theoretical minimum at 350km orbit is 40ms roundtrip, which would work for most games. But many complications, including position of the satellite, latencies within the networking components, packet loss etc, can easily slow this to 100ms+, which is unsuitable for many online games.

No, the round trip for electromagnetic waves at 350km it’s about 2 ms not 40. The lowest orbit of the satellites though would be 550km and not 350km, but it would still be less than 4ms. From where did you get the 40ms figure that it’s wrong by an order of magnitude?

I don't know where they got that figure from, but it is unrealistic to not also expect a decent amount of latency to be introduced by the transmission hardware, particularly under load. I have no idea how much, but this has generally been the case with most systems of this sort.

Electromagnetic waves travel at essentially the speed of light. The speed of light is roughly 300km per millisecond. So if they are 550km up, that’s roughly 4ms round trip. Even with horrible inefficiency, it won’t likely increase that by 10x.

>charlatan like Musk

I'm not a fanboy by any means but the guy built two companies and launched a car from his factory into space from a rocket his other business built. He's personally spearheading the early stages of commercial space exploration. I don't know that I'd describe him as a charlatan.

Musk did not found Tesla, but would like you to believe that he did: https://www.quora.com/Did-Elon-Musk-found-Tesla-1

Maybe 'charlatan' is unfair, but he's certainly more of a sales-and-hype man than a real engineering type. I don't understand why so many technical people are snowed by his razzle dazzle.

While true, the company was founded in July 2003 and Musk joined in February 2004. The first Roadster prototypes were revealed in 2006.

Acting like he hitched his flag to an already successful company is disingenuous.

And then there was paypal.

It's not clear to me how active Elon was with PayPal, I really think it was much more Peter Thiel that made it successful (although I am not claiming expertise). Elon founded x.com which merged with what become PayPal, but as PayPal started to become successful it was Peter Thiel at the helm. That doesn't mean Elon wasn't instrumental to its success, only that I cannot find much evidence that he was instrumental to its success.

https://en.wikipedia.org/wiki/PayPal#Early_history

> In October of that year, Musk made the decision that X.com would terminate its other Internet banking operations and focus on the PayPal money service.[25] In the same month, Elon Musk was replaced by Peter Thiel as CEO of X.com. The X.com company was then renamed PayPal in 2001,[26] and expanded rapidly throughout the year until company executives decided to take PayPal public in 2002.

And so what? founding a company is the easiest step (a little bit of money and paperwork). executing to make it the world leader in electric mobility is what really matters. So your point is really irrelevant.

What I have observed over the years is that Musk routinely burrows into engineering considerations, for better or for worse, most especially at SpaceX but also with regards to manufacturing, specifically, at Tesla. He is an engineering enthusiast with a well documented skillset.

Regardless of how we characterize Musk, however, reducing the issue at hand to a pro/anti Musk ad hominem argument is a distraction and a waste of time. It is suddenly relatively cheap to put a huge number of small satellites in low earth orbit. This creates a conflict with astronomical interests. What remains is a policy debate worth having.

SpaceX's statement may be ignorant, erroneous, or even deceitful. I have no doubt that the astronomy community identified the problem immediately and has been trying to bring it to public attention. However, as with light pollution at both optical and radio frequencies, they are relatively powerless compared to the interests with which they are in conflict. If the FCC is the arbiter of how many satellites a company can launch into LEO, they have already lost. This was a regulatory and legislative battle that they needed to be fighting, and probably were fighting, and basically had very little chance of winning unless they were somehow able to mobilize public support for earth-based astronomy against the telecommunications industry.

"Founder" is a label decided by the company, not by outsiders. Many Silicon Valley companies have "founders" who were not there on Day 1.

Founder is a word that has meaning, we shouldn't let companies dictate our use of language.

It's fun to watch people up and downvote me for just relaying what Silicon Valley founders have actually been doing for decades. I totally agree that it's a surprise to most people how it works, but I don't think "they" are going to change. It just is.

I find the "did Musk found Tesla thing" petty and unnecessary. Without Musk it would have been a footnote in history.

But I dislike your assertion that just because SV companies feel free to rewrite their history, we should consider that canonical.

It's totally valid to point out that Musk wasn't a founder, though using it as some kind of slight is juvenile.

eBay is free to claim it was invented to sell Pez dispensers and we're free to point out that's PR spin. Neither side is in the wrong.

I didn't assert that, nor did I say it was invalid to not understand the inside-Silicon-Valley use of "founder".

I was just explaining how to not embarrass yourself.

With all respect, I can't read your previous posts without taking the meaning I did, but the fault may be mine.

No, he wasn't a first-day founder. But he joined not to long after and it was his private money and him as a CEO which built Tesla.

Starting companies, even successful, relatively technical companies, does not preclude a person from being a charlatan. The charlatan part comes when he publicly dismissed the concerns of experts and claimed there wouldn't be a problem, but of course there was a problem.

> charlatan: a person falsely claiming to have a special knowledge or skill

"publicly dismissed the concerns of experts" i.e falsely claiming to have special knowledge

> Yes, I’m an astronomer and I can tell you this SpaceX statement is pure BS. The astronomy community absolutely thought of this before any of these satellites were launched. I’ve personally talked about it at public outreach events (and it was members of the public who brought it up) and topic has definitely come up at professional meetings...but there is just a general feeling of powerlessness, both from the point of how do you fight a company like SpaceX and a charlatan like Musk, and also from the point of many members of the public don’t care.

Why aren't you talking about any of the other constellations that are being built? They're all planning huge numbers of satellites, many of which are larger or in higher orbits than SpaceX's satellites. You can't single out Elon Musk's companies just because of a personal vendetta if you're actually trying to be fair and attack this from a technical perspective.

Many of the other constellations look unlikely to be completed.

> charlatan like Musk

If Musk was a charlatan, we wouldn't have this problem. Musk would have failed to put spacelink satellites in orbit and we wouldn't have this problem.

The reason why we have this problem is precisely because Musk isn't a charlatan.

> I also know a lot of people directly involved in SSA and all of them are very concerned with how much these new constellations are going to increase the risk of collisions

Just because they are concerned doesn't mean they are against SpaceX or Musk. Every venture is open to concern.

> SpaceX cultists

Is NASA and the US government SpaceX cultists? You act like Musk just sent this satellites up there without any warning or government approval. He didn't.

All you've done is toss ad hominems at Musk, SpaceX and those who support this venture.

I call Musk a charlatan because he tries to pass himself off as something he isn't. His physics and engineering knowledge is nowhere near the level he boasts about, and he often states things that an SME would find laughable were they not eaten up without question by so many ill-informed cultists. It's dangerous, and unfortunately it's probably going to result in even more harm to people before he's reigned in.

And to clarify, the SSA folks I was referring to are against these types of constellations particularly in the context of the speed and lack of oversight (and no, FCC/ITU spectrum approval has nothing to do with oversight and regulation of the physical objects in orbit) of these ventures.

I agree. I remember hearing/reading about similar problems from previous satellite constellations. Nobody thought of this means that SpaceX spoke with nobody who could tell them about this issue.

> “No one thought of this,” she said. > “We didn’t think of it. > The astronomy community didn’t think of it.”

Oh Really?

In 1979, NASA founded the Orbital Debris Program to adopt mitigation measures for space debris in earth orbit.

Apparently heaven forbids a web search on Astronomy & space junk. Or checking with astroimagery software to detect & mask frames contaminated with existing satellites streaks

That program's purpose is entirely different, though. It's focused on crashes between satellites, not avoiding impacts on astronomy.

SpaceX's constellation is already specifically set at a low orbit to prevent buildup of space debris. That impact was absolutely considered and mitigated from the start.

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