SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

https://spacenews.com/spacex-working-on-fix-for-starlink-satellites-so-they-dont-disrupt-astronomy/

by woliveirajr • 7 years ago

204 213 7 years ago

spacenews.com

Spare_account• 7 years ago

My first thought was that they should paint them with Vantablack, but then I wondered if that might be too dark?

Do they need to aim for a specific reflectivity or just aim for the lowest possible value?

wongarsu6• 7 years ago

I think the lowest possible reflectivity is desirable. Space isn't perfectly black but very close to it. Any reflectivity means you sometimes reflect something very bright like the sun and sometimes nothing, so you have the wrong brightness no matter what you do. Black dots are at least fairly unambiguous.

MojoDwarf• 7 years ago

I was thinking about this also but wonder if it would collect too much heat while in direct sun light.

SEJeff• 7 years ago

That is often considered, but the light is absorbed and turns into heat. Where does that heat go? It would fry the electronics with no way to get rid of it.

kevingadd2• 7 years ago

You could use some mechanisms to convert and dissipate the heat, though that doesn't come for free. Though the atmospheric pressure at that altitude is pretty low, you might be able to rig up some sort of peltier cooler setup to dissipate heat. Alternately if you can convert enough of the heat to electricity some other way, you could convert the heat back to light using LEDs or something and only turn on the ones facing away from earth, perhaps?

Plenty of other orbital devices have to deal with heat so I'm sure this is something that has existing solutions.

the8472• 7 years ago

reflectivity/aborbtion is more than a percentage value. it's also a hemispherical distribution. if you glued retroreflectors to the surface most of the light would go back in the direction of the sun and thus never hit the surface. Those are probably too costly or bulk for satellites. If specular reflections are the problem they might just apply a more diffuse coating.

topologistics• 7 years ago

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

That is absolutely ridiculous. The Iridium satellites were decommissioned recently and it was a big deal because, for the longest time, you had to check for "iridium flares" if you were using any type of sensitive equipment. Basically, the entire class of iridium satellites was highly reflective and they tended to create shooting star type phenomena, sometimes really really bright, bright enough to be seen during the daytime!

Maybe she didn't think of it, but to say the astronomy comunity didn't think of it is just blatantly absurd on its face.

On another note, I miss spotting iridium flares and I'm looking forward to a new class of satellites being added into my weekly observations.

readams• 7 years ago

They announced their plans years ago. The astronomy community could have raised concerns then. The fact that they didn't would indicate nobody connected the dots.

dylan6043• 7 years ago

The fact that they didn't would indicate nobody connected the dots.

Or that nobody knew who/where to contact someone to raise their concerns. A lot of people will think that if I just had this thought, then it must be pretty obvious so that others will have the same thought as well. No need for further action. Others will just not feel the need to spend their time/effort trying to look up the complaints department. Others might not even feel like it is their place to say anything.

wpietri4• 7 years ago

Your theory is that corporate responsibility ends when you make the first press release? That if specialists everywhere aren't paying attention to the business news, we've arrived at "who could have known"?

mentos• 7 years ago

Not a valid solution but I thought maybe SpaceX could launch a bunch of telescope satellites that could be used by hobbyists.

wongarsu6• 7 years ago

SpaceX directly profits from space enthusiasm, and having their in-house satellite team design such satellites (during downtime, as practice or testbed, etc) and launch them using unused capacity on existing launches would be way cheaper than anything NASA could do. It's not as absurd as it seems at first glance. Not a good replacement for a proper solution, but a nice idea for something they could do in any case.

dylan6043• 7 years ago

Could you imagine the enthusiasm from amateur astronomers, kids in school, etc where they could schedule time on a space based telescope? Sure, they won't be anywhere close to Hubble, but even a 6"-12" mirror in ~0% atmosphere would be very cool. And if it were a true constellation, you could schedule time on a satellite in the night time part of the sky during normal daytime class room time rather than trying to take a class field trip to a typical astronomy facility. You would also eliminate the most frustrating thing about astronomy: cloudy skies. And you'd also be able to see parts of the sky that you wouldn't normally based on location, ie Northern/Southern hemisphere.

chr13• 7 years ago

Why is it not a valid solution? It is actually a much better solution than using small low quality telescopes. If starlink is successful in a few years launching satellites will become cheap enough to allow us to launch multiple telescopes better than hubble, and we'll have equivalent of google earth with high quality images of night sky. Combined with VR why would anyone even want to use telescopes? (Maybe people who have personal memories linked to telescopes, like watching night sky with parents, but then even their children would prefer to use the VR version instead).

throwaway20483• 7 years ago

Because there is a difference between things that could maybe happen, and things that are almost certainly going to happen. Especially when the "maybe" is relying on the largesse of somebody else to fix the problem they created.

History is full of disasters and situations where that absolutely does not work out.

Pinning the near-entire future of astronomical observation on Musk's good will is ridiculous.

wongarsu6• 7 years ago

It will be interesting how they solve it without causing thermal issues. Just absorbing all light won't work, the energy has to go somewhere and the only viable way to loose it is through radiation (not much air around even in these low orbits). Maybe the satellites will be black on the earth-facing side and radiate heat on the other side?

My impression from the article is that they launch one coated satellite just to see if the coating helps at all, and how bad the thermal issues get, so SpaceX is still in the early stages of solving this. But if they keep up with launching 60 satellites every 2-3 weeks for the next months they have to make progress fast.

Fronzie• 7 years ago

Diffuse reflection might help as well. A sphere and a cube have very different maximum reflection values.

dylan6043• 7 years ago

“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.

XorNot• 7 years ago

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.

TeMPOraL3• 7 years ago

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.

9192631770_Hz2• 7 years ago

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.”

sunstone• 7 years ago

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

allovernow• 7 years ago

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.

mlindner2• 7 years ago

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.

s1k3b8• 7 years ago

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.

downrightmike• 7 years ago

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.

krastanov• 7 years ago

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.

takk309• 7 years ago

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.

buboard7• 7 years ago

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

buboard7• 7 years ago

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)

EE84M3i• 7 years ago

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...

tejtm• 7 years ago

“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

ceejayoz8• 7 years ago

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.

Iolaum• 7 years ago

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.

vasili111• 7 years ago

Also do not forget that SpaceX is not the only company that wants to launch low orbit satelites. I do not think it is possible to find any other real solution other then to move telescopes to space.

Tomte3• 7 years ago

Sure there is another solution: we ban them, or at least highly regulate them.

The idea that private companies can just do whatever, and there's nothing we can do is just so cliché HN.

lacker• 7 years ago

I am a big fan of astronomy, but satellites are doing a lot more for humanity than ground-based astronomy.

wongarsu6• 7 years ago

Nobody has jurisdiction over space. We can try to create an international agency and get all space fairing nations to submit to its regulations and rulings, but even if that was politically viable it would take years. Meanwhile Starlink will be deployed mid 2020 if no major delays happen

dang3• 7 years ago

You broke the site guidelines badly with this flamebait and generic tangent, which predictably started a wretched flamewar. Then you perpetuated it.

You do a lot of good for HN with your interesting submissions, but you've also been vandalizing HN with destructive comments for years. We've asked you not to do this many times.

https://news.ycombinator.com/item?id=20356880

https://news.ycombinator.com/item?id=18887148

https://news.ycombinator.com/item?id=17952388

https://news.ycombinator.com/item?id=17441941

https://news.ycombinator.com/item?id=17432633

https://news.ycombinator.com/item?id=17113849

https://news.ycombinator.com/item?id=17111984

https://news.ycombinator.com/item?id=14693327

https://news.ycombinator.com/item?id=11705439

Eventually the cost outweighs the benefit. I definitely do not want to ban you, so would you please review https://news.ycombinator.com/newsguidelines.html and fix this? All users here need to have self-control, and experienced contributors more so.

wongarsu6• 7 years ago

With James Web having an decently sized mirror on a space telescope that's not as ridiculous as it once was. Still we should search for cheaper solutions first.

https://www.eso.org/public/usa/images/eso1617z/?lang

mcbutterbunz• 7 years ago

JWST still hasnt launched after all these years. Building space based telescopes that will last years without maintenance is hard.

Rebelgecko4• 7 years ago

For some added context, JWST costs about 10x more than the most expensive terrestrial telescope ever built.

close042• 7 years ago

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

This implies the community was asked or involved in such a discussion and no objections were raised, which is unlikely.

Whenever some "armchair specialist" commented about Musk's plans to put people on Mars and the challenges with the radiation, the magnetic field, the etc. the answer was always "Do you think a room full of scientists haven't thought about that?". Well there you have it, straight from the source: sometimes they (claim they) do not think about "that". Question everything, worst case someone already thought of that.

ChrisClark• 7 years ago

Yeah, that's why Musk always asks people to come to him if they have a better idea. Even in large groups, or maybe especially in large groups, things can be overlooked.

He recently said in a video that if anyone can convince him an aerospike is better than their solution, he wants to know.

kevingadd2• 7 years ago

There is a cultural risk involved though - we don't know how comfortable SpaceX employees feel raising objections given how aggressive Musk has been against concerns in the past (see the somewhat credible reports that Musk angrily rejected yellow safety markings on equipment based on personal taste: http://nymag.com/intelligencer/2018/04/tesla-workers-getting...)

I've heard similar reports from former Tesla employees. They found it stressful working with him in many cases (his brilliance/openness to feedback aside) which could impact this a lot.

jdsully• 7 years ago

He also has a history of calling people pedophiles for disagreeing with his designs. Even when they are domain experts and he is not.

I think that’s more just PR and he’s not honestly seeking feedback.

acd• 7 years ago

Good that is is being fixed!

Regarding "The astronomy community didn’t think of it"

I think just because we have public spaces does not mean one can do whatever one wants with them.

1) There has been disturbances in the past of radio astronomy spectrum from communication equipment, this limits our ability to learn and observe space. 2) There will be visual disturbances if we launch of satellite constellation for visual astronomy 3) There will be space junk when these satellites run out of service.

dang3• 7 years ago

All: since people feel passionately about this, if you comment in this thread please make sure you're doing so thoughtfully and following the guidelines. Avoid flamebait, don't fuel flamewar, and definitely don't do personal attacks.

https://news.ycombinator.com/newsguidelines.html

kerng4• 7 years ago

Isn't it obvious that this will happen? It's like taking a picture of nature and having airplane evidence in it, or take a picture of a city or even countryside and there are cars in it.

I'm sure the same was said about cars and planes. It will be weird and things will drastically change - but so have things the last 2000+ years.

rtkwe3• 7 years ago

You can easily get yourself between cars and whatever natural thing you're trying to observe on the rare cases that what you're trying to study is anywhere near cars. The only way to do the same for Starlink is to launch multi-million dollar+ space telescope.

kerng4• 7 years ago

But in that case you have to travel to a remote location (most likely using a car or plane ironically).

Hence, is it so far fetched that if you want to explore space in future you will do it from a different vantage point? Like via a satellite, or maybe in 50 years you go to a space station or the moon directly to do so.

With tech it has always been this way- it's nothing new.

cbanek3• 7 years ago

(I'm not speaking for any of my current or past employers, just for myself, and how I've seen this play out. One employer being a telescope impacted by Starlink, and the other being SpaceX, I want both sides to succeed.)

First, astronomers know that satellites can disrupt observations. They've known for a while, and have had to deal with things like flares from Irridium satellites, which were probably when these problems were first taken seriously. (It was a design defect where shiny panels would reflect the sun in a very efficient way).

Astronomers use all sorts of image processing, because satellites aren't the only noise in the picture. The CCDs have to be kept cryogenically cool, and there's all sorts of electrical noise as well. There's not a lot of photons being collected in the grand scheme of things, so dealing with the noise floor is a real problem. There are all sorts of ways for removing tracks. And don't forget weather!

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.

Even if there is no light reflecting, these satellites could occlude a distant star or galaxy momentarily. You wouldn't see a streak as much as the light would go away and come back. This would affect how bright you see the star, since over the time of the exposure (let's say 30 seconds) you'll collect less light while something is blocking the light. This can also make it a bit more tricky to look at variable stars, where the light gets stronger and dimmer naturally.

I would say that astronomers definitely knew about these problems, since they have to deal with all sorts of similar problems, but the pitch didn't get fevered until people saw the first set of Starlink satellites and just how bright they were. SpaceX moves a lot faster than astronomy.

As for SpaceX not thinking about the astronomical implications of Starlink, I could believe that. I think most of them were more concerned with if it is possible rather than the implications of doing it. As much as I would think the two fields would know more about each other, I find they are very different and run in different circles it seems (launch vehicle industry vs astronomers), so I could easily see not much cross pollination between the two. For example, there were lots of NASA astronauts and air force people visiting SpaceX, but I don't remember one astronomer (not that I met everyone).

mstipetic6• 7 years ago

This sounds to me like a new technology and a way of operating has come and we're trying to make it accommodate the old way of doing things.

If we really have a way to launch thousands of satellites easily, can't we replace the terrestrial functionality with that? Let's launch hundreds of satellites observing near earth asteroids.

If a private company can do it, governments definitely can

whatshisface• 7 years ago

That's a good point. SpaceX could be the key to launching a horde of new Hubbles. However that's not so likely in the short run because everything is going towards the JWST.

Filligree• 7 years ago

Terrestrial telescopes are huge. Hubble is comparatively tiny, and launching a telescope the same size as the ones we use down here would be completely out of the question with any near-term launch capability.

cbanek3• 7 years ago

So while it sounds good that we've fixed the launch industry and can launch everything cheaper, that we should only have space based telescopes, space telescopes are a very different game from ground based telescopes.

First, as others have pointed out, is size. Ground based mirrors are very large, in the 10s of meters, and those mirrors are extremely heavy, like tons. You can't lift one of those mirrors up on one rocket, so you'll have to figure out some kind of in orbit construction. Not impossible, but we haven't assembled a lot of things in space, probably the biggest would be the ISS. But telescopes have tricky tolerances...

Which leads me to the next issue: not only is it heavy, but telescopes are fragile. They have to be very carefully calibrated and put together. Launching something into space tends to be a very bumpy ride, and making something that can withstand that kind of vibration for launch, and then the thermal problems while in space would be certainly not trivial.

But let's say you could build something and get it to work in orbit. Then it's still hard to service. Servicing the hubble to fix the optics was a very hard mission, and the hubble is relatively close to the earth. And that was when we had the shuttle, which we don't now.

Cooling is very tricky for both telescopes and space. Since there's no air to radiate to, you can get big thermal gradients over the length of your craft and you have to be very careful how you point it. Same for the optics and the camera, you want to make sure they have as little thermal gradient as possible.

Unlike a lot of commercial satellites, many scientific probes and telescopes are constantly refitted and reused. Ground based telescopes frequently reuse the same expensive (typically one-off) mirrors and put better cameras on them all the time. This is pretty hard to do in space.

That being said, being in space does have a lot of advantages, the most obvious one being a lack of atmosphere to mess with your observations. But assembling large telescopes in space still isn't exactly easy.

I think over time though, we will be heading to more space based telescopes as the cost comes down. But many slower moving telescope projects (mostly slow due to government funding) were started before Starlink was even announced.

dnautics3• 7 years ago

As an expert would you be able to comment on my speculation:

It seems like this whole hullabaloo is because a SpaceX launch happened to coincide with a rare event at an inopportune time:. The alpha monocerotids have a narrow band with a long recurrence time (2h window, with a peak recurrence on the order of 10 years). Moreover, some monocerotid observers are in parts of the world where they will appear near Dawn or dusk, so yes some of the starlinks will flash (as you mentioned). In general, the SpaceX launches will only cluster in that fashion a few days after launch as they haven't disperesed into final formation yet. Any other time this wouldn't be a problem.

pcunite• 7 years ago

We want to make sure we do the right thing to make sure little kids can look through their telescope

Before the end of next year, there is going to be 12,000 of these units above our Earth. One must certainly hope.

portillo• 7 years ago

I would bet that there will be no more than 1,200 (if they raise the money needed to launch and manufacture that many).

And I would also bet that even in an 8 year time-horizon, they will not launch 12,000 satellites for Starlink because simply, there will be no market for so much capacity. In my opinion, we are heading towards an Iridium, Teledesic, Globalstar 2.0 scenario.

phkahler• 7 years ago

On the plus side, Starship will be able to launch more and bigger space telescopes for lower prices, to places beyond the Starlink constellation. That doesnt help ground based observations though.

rrss5• 7 years ago

Last time this was in the news, there was another discussion on HN: https://news.ycombinator.com/item?id=20095462.

User 'twtw asked the following, with no responses:

Why didn't the IAU petition the FCC during the comment period for SpaceX's application? Seems sorta weird to wait for the first launch to express concerns when the application was submitted to the FCC many months ago (and I think I recall an earlier version years ago).

I think this is an interesting question. There are a number of commenters criticizing SpaceX's claim that "no one thought of this." I'd be interested in their response to this question. If so many people knew it was going to be a problem, why not raise those concerns to the organization tasked with regulating this stuff?

buboard7• 7 years ago

On the other hand we could use all this reflectivity ( and a ton more! Adding space sails on each of those) to cool the earth

antognini• 7 years ago

As an astronomer once upon a time I follow a number of my former colleagues on Twitter and pretty regularly see them posting images that have been ruined by Starlink. Here is one from just 12 hours ago:

https://twitter.com/MassiveStarGuy/status/120358895831320576...

This is going to have a bigger impact on the more expensive observations that require long-duration exposures.

justin663• 7 years ago

This definitely wasn't ruined (it's amateur video) but if anyone wants to see Starlink photobombing an astronomer, this amateur video of a recent meteor shower is an example:

https://www.youtube.com/watch?v=uHI8Z5qpd6I

(an astronomer friend thought I'd be able to identify the satellite amongst all the meteors, which was sweet... I think it's a bit after the 2 minute mark)

ricardobeat2• 7 years ago

Is it the one making a line starting from the bottom left corner, or the thing that makes a very short bright streak at 2:08?

woliveirajr• 7 years ago

Aside note: I didn't imagine one could see / film that much meteors during the night in some city. If I remember correctly, I saw 2 or 3 my whole life, and was driving at some road.

clon• 7 years ago

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

It seems probable that this is one of the things that can be ruled out. I find it inconceivable that none of the thousands of brilliant heads in SpaceX never thought of this.

- They spoke, but were not heard

- They never felt like speaking

coretx• 7 years ago

SpaceX sabotaging earth based astronomy sounds like yet another business trying to create a market/demand for itself. Herefore I bet my ass they'll do just too little to fix things and just enough in order to not be prosecuted.

ErikCorry• 7 years ago

I'm not an expert, so take this with a grain of salt, but isn't this fixable with mirrors and angles?

For a satellite in LEO most of the light is coming from the sun and a much smaller amount is coming from earthshine and perhaps the moon. If your solar panels are on an articulated arm it should be possible to place them so they reflect the light upwards and the satellite's body is in the shadow of the panels. Now the only light on the satellite (and the back of the panels) will be the earthshine, and you can perhaps combat that by painting the satellite black. If it's always in the shadow of the solar panels then heating shouldn't be a problem, right?

As I say I'm not an expert and there are probably multiple reasons this won't work.

notatoad• 7 years ago

Hoping i can get an answer here from somebody who actually knows, and not just a spacex fanboy or hater: what's the actual scope of the problem here?

Shotwell's response and other comments i've seen seem to imply starlink satellites are primarily impacting amateur astronomy ("kids looking through telescopes") and that scientific research is performing post-processing to the recorded images which can mostly eliminate the effects of the starlink satellites. Is that accurate, or is this also impeding telescopes at the big observatories?

joshvm• 7 years ago

Shotwell's comment is extremely patronising under the circumstances. This doesn't affect kids looking through telescopes at all. If it's bright enough to see through an amateur telescope, it's bright enough to ruin a precision observation from a real instrument. A large part of the outcry is lack of tact from Spacex.

Satellites in images is not new and has caused astronomers problems for a while. It's not common, but most people in the field know someone it's happened to.So now the issue is there will be an order of magnitude objects in space.

Any kind of time series where you observe brightness over time would be affected by a satellite impinging the field. Spectroscopic measurements would also be affected. Astronomers use incredibly sensitive instruments looking for very faint objects - if a bright object is in the field of view, it can saturate the detector and ruin the image.

For context some measurements, like imaging exoplanets, are so precise that you have to block the light from the (already faint) target star to see what's around it.

In reality it's amateurs that can compensate with post processing. Professional astronomers are likely to just trash the data and try again.

Then there are upcoming survey instruments like the LSST which take very wide angle images (I expect they already have some mitigation strategy becuase of other spacecraft). That said, the smaller your field of view, the lower the chance of a satellite impinging.

One solution could be a mechanical shutter which could be activated when a satellite is about to impinge the field, or triggered by a database of satellite ephemirides.

chmaynard• 7 years ago

Here's a novel idea for a fix: admit that Starlink is flawed, shut down the project, and come up with another way to make money.

avocado4• 7 years ago

This has already been tried by Luddites in 19th century, not a new idea.

clSTophEjUdRanu• 7 years ago

LEO just got a lot cheaper. Get ready for humans to fill this space with shit since it's economical.

tehjoker• 7 years ago

I don't understand why SpaceX is allowed to make this decision nearly unilaterally. This is so similar to how the modern tech companies treat data extraction: they find something unregulated and push until they get pushback.

This should have a been a worldwide consultation.

jsjohnst3• 7 years ago

Since there are folks here in the field, does anyone know what the feasibility of building something similar to the VLA, but with thousands of smaller satellites? If doable, seems potentially possible to cover a lot more sky at once with less terrestrial interference. No idea if this is practical or not.

Rebelgecko4• 7 years ago

There's a number of problems w/ doing interferometry in space, which vary a bit depending on the frequencies you're working with—

Thermal: Parts of the detectors need to be very cold. Depending on what you're doing you may have to cool parts of the satellite down to 5 kelvin (-450°F) or even lower. You need to use a cryocooler than won't vibrate too much and impact your measurements.

Power: Each VLA antenna uses about 18kW just for cooling. That's a lot of juice— back of the envelope math says you need a lot of solar panels for that. An area smaller than a football field but bigger than a tennis court. It's manageable if you're only building a few of these, but less practical if you want to build 64 or even thousands.

Positioning: Most proposals for space based interferometry didn't actually consist of individual satellites. They're typically one big satellite with telescopes sticking out on different arms. If they're free-flying, it gets a lot harder to know the precise relative positions of the different receivers.

jsjohnst3• 7 years ago

Each VLA antenna uses about 18kW just for cooling.

That’s likely at minimum partially proportional to the size of each VLA antenna, no? Each VLA antenna is larger than any antenna ever put in space I believe.

If they're free-flying, it gets a lot harder to know the precise relative positions of the different receivers.

That’s exactly what I thought would be one of the biggest challenges, but wasn’t sure if we’d solved that problem or not yet.

SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy

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