SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy
spacenews.com
spacenews.com
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).
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
I don't know much about astronomy, but from what I understand the Earth's atmosphere is hard to deal with, why aren't we talking more about what can be done with this new tech, and not how it makes current things more difficult
It's more than a decade late and billions over budget.
The required precision for construction of telescopes is incredible, and doesn't translate to space well, especially once you start talking about apertures that even folded won't fit into even the largest Starship SpaceX is proposing.
Ground-based astronomy is here to stay and with good reason. SpaceX needs to avoid or minimise the harms to these users of the night sky.
There is another aspect of harm, too - the casual observer. The night sky is a precious resource and shared by all. Introducing huge constellations which in many parts of the world will be visible year-round (and in some quite heavily populated areas like northern Europe, even through the night at some times of year) is like building a huge mobile phone mast outside someone's window and expecting them not to complain, but on a much larger scale.
Light pollution is a huge issue, and satellites can pollute just as well (if not more effectively) than ground based sources - it needs to be an ecological consideration of any launch.
https://en.wikipedia.org/wiki/List_of_largest_optical_telesc...
In general, I'm fine with scientists needing to accommodate people more than they had to 100 years ago.
As an example, why is this area named Observatory Hill? https://www.google.com/maps/place/Observatory+Hill,+Cambridg...
> In general, I'm fine with scie!tists needing to accommodate people more than they had to 100 years ago.
Indeed, that's the majority opinion.
https://www.rmg.co.uk/discover/explore/great-equatorial-tele...
This process is just starting with satellites. Can you see the connection now?
Why do you think telescopes in space - where they don't need to fight gravity just to stand - can't soon, with reasonable development, surpass land-based ones in capabilities?
Astronomers have been talking and acting for decades to take advantage of new technologies like orbital observatories.
Hubble is thirty years old, and is being used now as a reference. I don't understand all this negativity. Had we had this mindset, Hubble would not have been there
True but to their credit SpaceX's launch prices are substantially lower than pre-existing options and they have been a leader in a step change in competitive launch options coming to market.
and SpaceX customers hope to pocket a lot of use for that money. So taking that point literally - tiny astronomer's society is against the whole Earth load of Spacelink customers, and of course those customers' needs on average trump astronomers' ones.
I'm exaggerating, of course.
There is a question of whether 100 a foot diameter telescopes can work as well or better than one 8 foot one. Or 500. If it's about photons hitting the lens, do enough lenses in an area and post-processing make up for the fact that they aren't connected?
With capabilities to launch as cheap as Spaceship promises, we can develop space manufacturing rather soon.
This looks like something reasonably doable on Earth orbit with the current launch capabilities.
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.
We then add active optics to compensate for atmospheric distortion, alter airline routes and city lighting to help improve conditions, and then pray for no clouds on the nights we want to observe.
Constructing telescopes in space will become a reality within the next decade, while terrestrial telescopes currently in planning will be finding it harder and harder to navigate the mixture of light pollution, accessibility and indigenous rights. I expect there are terrestrial telescopes already in planning and even at early stages of construction which will never be finished. Between the ever-growing forest of red tape and the ever shrinking cost of building space telescopes in orbit, there will be an inflexion point where it makes sense to dedicate the remaining budget of a terrestrial telescope project to building its spaceborne replacement.
Seemingly fantastically - SpaceX is currently constructing a system designed to launch 100 tons to LEO, for as low as $35/kg [1]. Musk says this capability is what the Starlink business is to pay for. It appears lately, more realistic than it has sounded.
[1] https://caseyhandmer.wordpress.com/2019/10/29/the-spacex-sta... ( https://news.ycombinator.com/item?id=21397285 )
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.
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.
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.
(Also, why do I get a feeling the two of us talked about using satellite constellations and interferometry on HN before?)
Thanks for remembering!
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.
If I have the opportunity, I’ll mention your suggestion.
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.”
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
One very important market they're going after is global arbitrageurs.
It’s almost like a Gibson or Stephenson novel.
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.
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.
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'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.
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.
Acting like he hitched his flag to an already successful company is disingenuous.
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.
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.
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 was just explaining how to not embarrass yourself.
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.
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.
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.
>. “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.”
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.
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)
Note, this section was added June 03 2019.
https://en.wikipedia.org/w/index.php?title=Starlink_(satelli...
> 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.
"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."
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
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.
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.
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.
If you cared you could LinkedIn message a SpaceX employee. Tweet at Elon Musk. Connected with nyt or other media who’d love to run such a story.
...etc
SpaceX had to get approval from the FCC to launch these satellites. There was a comment period intended to provide an opportunity to voice these concerns. I looked into this the last time it was in the news (late May?), and could not find any petitions that raised concerns about reflecting light. There were several from other satellite companies requesting that the FCC deny the application based on concerns about increased risks of collision and/or radiointerference with their licensed bands.
But IAU publicly decried satellite constellations in January, months before May-- and this public statement followed literally years of IAU discussions and discussions with SpaceX, etc.
Despite that, years later, SpaceX is only just getting around to taking small mitigation measures now, after two launches.
I don't see why the FCC wouldn't consider impact to visual astronomy, when they did consider increased collision risk (also unrelated to any regulated frequencies).
> IAU publicly decried satellite constellations in January, months before May
Can you link to information about this public statement from January? When I google "IAU satellite constellations," I find only https://www.iau.org/news/announcements/detail/ann19035/ from June.
It's fundamentally a radio license:
https://www.law.cornell.edu/cfr/text/47/25.114
> when they did consider increased collision risk
Yup, they are supposed to evaluate orbital debris and collision risk, too, 47 CFR 25.114(d)(14). That, and equitable service (for some services) to Alaska/Hawaii are the only non-radio concerns they are permitted by regulation to consider.
Where is the restriction to only those concerns? 47 CFR § 25.156 has some pretty vague language about "the public interest, convenience and necessity."
Thanks for pointing out that the FCC is required to evaluate orbital debris and collision risk, but I don't think the FCC is prohibited from considering other concerns (and i might be wrong on that).
The public comments relate to the adequacy of the application, which is required to address those points.
Yes, users of radio frequency spectrum do have public interest obligations. Thus far, for spacecraft this has been entirely confined to coverage requirements (aka, helping out Alaska when it's not infeasible).
It would be highly unusual-- and likely to be overturned in judicial review-- if the FCC were to decline to issue a radio license because of secondary impacts of the business. (Outside the specific areas where the FCC has been granted oversight-- environmental impacts of radio towers, space debris mitigation, safe operation of radio facilities, etc).
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?
https://twitter.com/MassiveStarGuy/status/120358895831320576...
This is going to have a bigger impact on the more expensive observations that require long-duration exposures.
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)
The idea that private companies can just do whatever, and there's nothing we can do is just so cliché HN.
By contrast, earth-based telescopes are doing lots and lots of science right now.
One example: https://www.usap.gov/technology/1935/
> Amundsen-Scott South Pole Station uses communications satellites that serve as relay stations, receiving radio signals from one location and transmitting them to another. The United States Antarctic Program utilizes the satellites for the transfer of South Pole science, operational, and weather data, as well as Internet, telephone, and email services.
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.
Please don't censor people just because they criticize HN or the community.
I also read the rest of the comments linked as examples and some of them where obvious to me and some were not.
I'm not a native speaker though and I realize dang has a huge advantage there as well as access to see detailed voting statistics to see what riles people up.
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.
Genuine question: is your opinion about these satellites based on working in some related field, or simply on dislike of greedy capitalists? I have a phd in physics and have friends who work as astronomers, with whom i've talked about this. Of course there is always a chance that we misunderstand everything, but i have never seen any plausible arguments for why are some people considering starlink to be the end of world for astronomy, and i don't understand why are there so many people on hn defending "poor astronomers" from "The Evil Corporation".
For some types of astronomy --- especially larger fields -- heavily increased use of LEO may reduce the effective hours of observation by 4 hours a night by spoiling most exposures, while creating some impact at other hours. This is more than a 33% reduction in throughput.
Even with a smaller satellite population, there's been losses of valuable data. Two images in an early sequence of SN1987A had a (amazing improbable) perfect satellite streak right down the middle.
Or there's this past APOD https://apod.nasa.gov/apod/image/1910/M31Before_Scherer_4298... where we see the effect of the current satellite population (and a few planes with the ~10 parallel lines from upper right to lower left) on a big stack of images of Andromeda. Zooming in makes it obvious there are many more trails than leap out -- including a few neat tumbling objects's with periodic brightness changes (not the plane strobes).
What's tripling the number of satellites going to do?
I am concerned about increasing satellite counts for a few reasons (including the potential debris problems) I don't think it should preclude progress, but existing and future stakeholders (astronomers, people who enjoy dark skies, current/future users of LEO) should be considered.
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.
He recently said in a video that if anyone can convince him an aerospike is better than their solution, he wants to know.
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.
Plenty of yellow lines in those.
I think that’s more just PR and he’s not honestly seeking feedback.
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?
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.
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.
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.
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.
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.
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
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.
Do they need to aim for a specific reflectivity or just aim for the lowest possible value?
Plenty of other orbital devices have to deal with heat so I'm sure this is something that has existing solutions.
Same thing with the LED idea converting that heat into electricity requires some heat differential which requires... a radiator.
Thermodynamics says "lolnope", I'm afraid. You need a temperature differential to convert heat to power.
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.
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.
This should have a been a worldwide consultation.
Before the end of next year, there is going to be 12,000 of these units above our Earth. One must certainly hope.
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.