What would you prefer: Satellite-streamed cat GIFs – or a decent early warning of an asteroid apocalypse?
- Reference: 1598511726
- News link: https://www.theregister.co.uk/2020/08/27/satellite_constellation_astronomy_warning/
- Source link:
A report
[1]PDF
out this week compiled by the Satellite Constellations 1 (SATCON1) committee [2]outlined the repercussions of the growing number of metallic birds in low-Earth orbit (LEO) on astronomy.The high reflectivity of these satellites ruins images of the night sky, as far-away objects are covered by bright streaks leftover from the passage of the satellites. The effect was [3]noticed as soon as SpaceX flung its first constellation of 60 internet-relaying satellites into the heavens last year. That number has steadily risen to 655 as of this month. And with tens of thousands more on the way, the astronomical community is racing to come up with solutions to minimize their impact on science.
Good news: NASA boffins spot closest near-Earth asteroid ever. Bad news: We never saw it coming. Good news: It's also really small [4]READ MORE
The satellites appear brightest at twilight, and, unfortunately, that’s the best time to inspect near-Earth objects. Detecting and monitoring asteroids is time-sensitive; there’s a limited window to measure important properties such as their size and orbit to predict where they are headed and what effect they will have if they reach our world. If a satellite blocks the view of a space rock, astronomers could lose sight of their target and be unable to accurately warn us of an impending collision.
“Asteroids and comets have frequently impacted Earth in the past and will do so in the future, over long intervals with dramatic consequences, if not discovered and mitigated,” the report said. The American Astronomical Society, which jointly organized the study along with the US National Science Foundation, [5]added : "LEO satellites disproportionately affect science programs that require twilight observations, such as searches for Earth-threatening asteroids and comets."
Other objects, particularly exoplanets and stars orbiting directly behind the trail of these pesky birds, will also be tricky to find. The most successful way of detecting exoplanets, known as the transit method, involves measuring the periodic brightness of host stars, a winking effect caused by planets moving in from of them. The reflected light from satellites, however, will drown out the glow emitted by these far-away suns, and, in turn, their planets won’t be seen, either.
“Some of the most severely affected targets will be the M dwarfs, since cooler stars at a fixed distance will suffer larger relative effects. With the full constellations deployed, it will be impossible to detect super-Earth planets around M dwarf stars crossed by satellites,” the SATCON1 committee said.
But that’s not all: these massive constellations of telecoms satellites may spoil astronomical surveys probing for dark energy or gravitational waves. Over time, even amateur skywatchers will have to get used to them zipping across their field of vision as they look through their telescopes.
It is impossible to calculate the risk or the impact of losing such opportunities to discover the unexpected
The greatest loss, assuming there are no killer asteroids, will be if the internet-relaying satellites impact the ability to find and observe completely new types of objects and processes that have yet to be discovered. “It is impossible to calculate the risk or the impact of losing such opportunities to discover the unexpected without knowing what we’re missing. But some phenomena will surely go undiscovered as a result of significant interference from LEO satellites,” the report cautioned.
There are a number of steps the committee recommended to minimize the negative effects of these satellites. Companies can work towards making their birds less reflective or promising to not launch them above 600 kilometres – a distance where they become visible all night.
Observatories will have to shuffle their schedules around to monitor the sky at times when interference is minimal. Astronomers will have to develop new techniques that remove the extra brightness or annoying trails of light produced from the satellites in images.
“The impacts of large constellations of LEO satellites on astronomical research programs and the human experience of the night sky are estimated to range from negligible to extreme, depending on factors including the scientific or other goals of the observation, the etendue of the facility, the observing strategy and ability to avoid satellites, and the ability to mask or remove satellite trails in data,” it concluded. ®
Get our [6]Tech Resources
[1] https://aas.org/sites/default/files/2020-08/SATCON1-Report.pdf
[2] https://aas.org/satellite-constellations-1-workshop-report
[3] https://www.theregister.com/2019/06/05/international_astronomical_union_satellite/
[4] https://www.theregister.com/2020/08/19/nasa_near_earth_asteroid_2020qg/
[5] https://aas.org/press/report-offers-roadmap-mitigate-effects-large-satellite-constellations-astronomy
[6] https://whitepapers.theregister.com/
Re: Headline question
I'd be happy with the eee girl. Because eee is one of the syllables for meow, of course. No other reason. So we're all good?
If only there were some kind of paint with 99.999% absorbtion
And Anish Kapoor didn't have the rights to stop people painting things with it...
Re: If only there were some kind of paint with 99.999% absorbtion
Kapoor has negotiated an exclusive licence to use a particular material produced in a certain way... other materials with similar properties are available, and who knows, there might be reasons that Vanta Black is not the ideal coating for space vehicles.
Maybe microgravity vacuum is a suitable environment for depositing nanotubes on a substrate - i.e, develop a system for coating the satellites in orbit.
Re: If only there were some kind of paint with 99.999% absorbtion
I think there can be over-heating issues if you paint the whole thing black.
Re: If only there were some kind of paint with 99.999% absorbtion
What about red doors?
Re: If only there were some kind of paint with 99.999% absorbtion
I think there can be over-heating issues if you paint the whole thing black.
Solar panels block the bulk of light from reaching the satellites, and I guess a pure black material would radiate back into space at not far off the same rate it receives heat.
Fasten a half-decent camera to the top of the satellite and use them as a huge distributed lens is my solution.
Re: If only there were some kind of paint with 99.999% absorbtion
" a pure black material would radiate back into space"
The reason black is black is because it absorbs all incident radiation, certainly in the case of a pure black, it would not reflect or re-radiate anything.
Re: If only there were some kind of paint with 99.999% absorbtion
> ... not ... re-radiate anything.
Erm, [1]Black-body radiation .
[1] https://en.wikipedia.org/wiki/Black-body_radiation
Re: If only there were some kind of paint with 99.999% absorbtion
Indeed: [1]Black 3.0
Note the condition of sale! "Note: By adding this product to your cart you confirm that you are not Anish Kapoor, you are in no way affiliated to Anish Kapoor, you are not purchasing this item on behalf of Anish Kapoor or an associate of Anish Kapoor. To the best of your knowledge, information and belief this material will not make it's way into the hands of Anish Kapoor. "
[1] https://culturehustle.com/products/black-3-0-the-worlds-blackest-black-acrylic-paint-150ml
Can anyone provide a quick comparison between ground-based telescopes and space-based telescopes? I'd imagine that the advantage of ground based telescopes is ease of constructing very large structures. Is it impractical / uneconomic to use the ever cheaper access to orbit to launch a few big / many small telescopes for detecting asteroids?
Hubble cost 4 billion USD for a 2.4 metre mirror telescope, Gran Telescopio Canarias cost 130 million EUR for a 10.4 metre telescope. Considering a shuttle launch at the time cost 450 million USD, we can surmise that satellites are seriously pricey. For what they're looking to do, ground based is still the best option.
How about my telescope is ground base as am I and the other dozens of kids who sometimes use it.
There are also thousands of ground based telescopes including those of amateurs, many important discoveries have been made or aided by them.
Still we can't let science and the potential it has to advance our knowledge while also tracking potentially extinction event objects get in the way of money, can we?
Although it is an order of magnitude cheaper than during the Apollo launches, launching a kilo of mass into low earth orbit is still pegged at over [1]$2700 , which is not negligible.
There is another matter to consider, the volume available for launch. On the [2]Falcon Heavy , Humanity's most capable launcher at this time, the available space to launch is 13.2 meters high and 5.2 meters in diameter. I'm sure boffins could fit a telescope in there - the Hubble space telescope is out there after all and it's smaller than that, although [3]not by much .
So the problem is more along the line of we can launch another Hubble space telescope, but we can't launch anything bigger at this point in time.
[1] https://theconversation.com/how-spacex-lowered-costs-and-reduced-barriers-to-space-112586
[2] https://en.wikipedia.org/wiki/Falcon_Heavy#Rocket_specifications
[3] https://en.wikipedia.org/wiki/Hubble_Space_Telescope
The Falcon 9 doesn’t have that big a payload fairing which limits its ability to throw telescopes into space. This is one reason why NASA is going to use an Ariane 5 to fire the James Webb into orbit - if and when it is ever finished. If you want an all-American rocket for your telescope either the Delta IV Heavy or the Atlas 5 are the ones for putting mirrors into space.
And even if it does get finished, it needs to be ready not too long after the Ariane 5 goes out of service. ESA don't want to be storing one final booster and keeping the launch pad in useable form for too long.
Surely you can, er, telescope a telescope?
(just had to pack an astronomical telescope prior to moving house. Turns out you can't. Oh well...)
Asteroid hunting doesn’t use the same type of ‘scope
What they are after is a wide field observation and the comparison of images between different timed shots. Some of the Earth-based versions use standard camera lenses. The mirrors therefore don’t need to be huge, and given a cheap launch it doesn’t need to be vastly more expensive than a ground based model given that they can use smaller mirrors in space.
Elon Musk
is such a dick!
no one asked for or wanted these. Space X didn't ask any country whether they were happy to screw up the night sky for every country in the world. Yet he carried on doing it.
Utter arrogance...
The same guy who told everyone his wife was dead when they broke up & who called a guy a paedo because he told him that his submarine wouldn't work in the tight confines of a cave.
Balance
I've not managed to find a balanced opinion on this issue (not knocking El Reg here, they are reporting on other peoples statements and are not themselves "space experts"). It seems to divide into "This is the end of all astronomy as we know it and don't come running to us when an asteroid hits us" and "seriously, there is nothing at all to worry about here". Presumably the truth is somewhere in the middle.
I will admit to finding the "oh, it's just for cat pictures" a bit tiresome though. Starlink at least have said that their pricing will probably be based on ability to pay. i.e. cruise ships, airlines, etc. full of (comparatively) rich people will pay full wack to get their cat pictures but remote villages in less developed areas of the world will not. They may even get the equipment/bandwidth for free and can then get access to health information, education, etc., etc. So there is opportunity for genuine global social good to occur here and that does need to be considered along with the other positive/negative aspects of these large shiny constellations...
It's a tougher question than it looks. Good Internet access for poor countries and rural areas is all kinds of useful, not just for slinging porn. Honestly, while I would not sacrifice amateur astronomers' hobbies for the sake of cat videos, I would for the sake of, just off the top of my head, improving access to education or easier trade for farmers in third world countries. Besides, in a world of hundreds of thousands of satellites, an amateur astronomer might be able to rent time on a space-based small telescope for cheap, and that would be pretty cool.
But I'm more concerned about professional astronomy, and I don't see a way to easily have our cake and eating it too there. Ultimately, the ideal situation would be one where serious astronomy is mostly done from orbit. Observing stuff from space would be better even without the satellites getting in the way. Think what we could see with an orbital telescope that's as big as some of our ground-based ones!
The problem is that building such a thing is economically unfeasible, unless we either get launch costs way down, or we get way better at building stuff in space. Neither of those things is going to happen unless space gets profitable. So, yeah, tough question.
Poor Countries?
These satellites are not really for poor countries. They are getting or have mobile and fibre. The fact that many are mortgaging their resources and other infrastructure to China to get it is a separate problem.
The fact is that almost no-one actually needs these. The real use is a very niche market and the quantity isn't needed for cruise ships (which are stupid) or air travel (of which there is too much). Even with 10,000 the capacity is tiny for any given area because they are in LEO.
Re: Poor Countries?
Deploying fibre in rural areas is vastly expensive, and mobile data is still expensive while proving much less bandwidth. Even in the first world (rural USA for example) then sparsely populated areas have little or no (ground based) connectivity. There are large parts of the world where this kind of connectivity would be a godsend.
Re: Poor Countries?
My wireless BB is a lot cheaper than Musks offering. I somehow doubt rural Africa is going to turn into an economic powerhouse because it can watch netfils and disney simultaneously when all it really need is access to local markets which wont be able to afford Musk either.
Elephant in room
The economic and technical case for LEO internet is weak. It's better to increase rollout of fibre, coax (fibre to street) and more mobile masts.
Perhaps in 10 to 20 years these will be gone.
The capacity per 10 km is a tiny fraction of mobile which is a tiny fraction of fibre or fibre to the kerb solutions. They also have a poor operational life and the launches are environmentally poor.
Hmmm... Take half a dozen Starlink frames and bolt them together, keep the command and control bits, propulsion system and solar array from one of them, and you've got a nice bus for a 1m telescope that could be launched along with a batch of actual Starlinks. Feels like a nice student project to sort out a design that could be easy to manufacture and put several into orbit.
Headline question
Cat GIFs obvs. And why isn’t there one in the article?