Slashdot is powered by your submissions, so send in your scoop

 


Forgot your password?
Close
typodupeerror
×
Space Communications

Astronomers Say a New, Huge Satellite Is As Bright As the Brightest Stars (arstechnica.com) 83

Posted by BeauHD from the blinded-by-the-light dept.
An anonymous reader quotes a report from Ars Technica: Last month, a Texas-based company announced that it had successfully deployed the largest-ever commercial communications satellite in low-Earth orbit. This BlueWalker 3 demonstration satellite measures nearly 65 square meters, or about one-third the size of a tennis court. Designed and developed by AST SpaceMobile, the expansive BlueWalker 3 satellite is intended to demonstrate the ability of standard mobile phones to directly connect to the Internet via satellite. Large satellites are necessary to connect to mobile devices without a ground-based antenna. [...] Since BlueWalker3's launch in September, astronomers have been tracking the satellite, and their alarm was heightened following its antenna deployment last month. According to the International Astronomical Union, post-deployment measurements showed that BlueWalker 3 had an apparent visual magnitude of around 1 at its brightest, which is nearly as bright as Antares and Spica, the 15th and 16th brightest stars in the night sky.

For a few years, astronomers have been expressing concerns about megaconstellations, such as SpaceX's Starlink satellites. While these are more numerous -- there are more than 3,000 Starlink satellites in orbit -- they are much smaller and far less bright than the kinds of satellites AST plans to launch. Eventually, AST plans to launch a constellation of 168 large satellites to provide "substantial" global coverage, a company spokesperson said. Even one is enough for astronomers, however. "BlueWalker 3 is a big shift in the constellation satellite issue and should give us all reason to pause," said Piero Benvenuti, a director at the International Astronomical Union.

The organization of astronomers is also concerned about the potential for radio interference from these "cell phone towers in space." They will transmit strong radio waves at frequencies currently reserved for terrestrial cell phone communications but are not subject to the same radio quiet zone restrictions that ground-based cellular networks are. This could severely impact radio astronomy research -- which was used to discover cosmic microwave background radiation, for example -- as well as work in related fields. Astronomers currently build their radio astronomy observatories in remote areas, far from cell tower interference. They are worried that these large, radio-wave transmitting satellites will interfere in unpopulated areas. "We are eager to use the newest technologies and strategies to mitigate possible impacts to astronomy," AST said in a statement to Ars. "We are actively working with industry experts on the latest innovations, including next-generation anti-reflective materials. We are also engaged with NASA and certain working groups within the astronomy community to participate in advanced industry solutions, including potential operational interventions."

AST is "committed to avoiding broadcasts inside or adjacent to the National Radio Quiet Zone in the United States [...] as well as additional radioastronomy locations," adds Ars.
This discussion has been archived. No new comments can be posted.

Astronomers Say a New, Huge Satellite Is As Bright As the Brightest Stars More

Astronomers Say a New, Huge Satellite Is As Bright As the Brightest Stars

Comments Filter:

  • Huge antenna (Score:3)

    by CaptQuark ( 2706165 ) on Saturday December 03, 2022 @02:22AM (#63098612)

    Since BlueWalker3's launch in September, astronomers have been tracking the satellite, and their alarm was heightened following its antenna deployment last month.

    Interesting. I looked at the photo of the antenna and it shows 148 modules with 16 antenna elements on each, all mounted on a white background material. It looks like changing the structural material to something less reflective could go a long way to reducing the light pollution this emits. Now they have to figure out how to reduce the radiation away from the "radio quiet zones" that radio astronomers require for some observations. https://ast-science.com/spacem... [ast-science.com]

    • Re:Huge antenna (Score:5, Informative)

      by Lord Rust ( 8424069 ) on Saturday December 03, 2022 @02:52AM (#63098644)
      You could cut the glare by painting satellites black, but there's a reason for the white color: Temperature control is a huge problem in space as vacuum is an excellent insulator. As your satellite slowly rotates, parts of it move from shade to sun and back. Sunlit sections can get quite hot (~100 C = 200 F) while parts in shade can fall to -170 C = -300 F! There are many ways to mitigate this problem. Making reflective/white helps. If you do not absorb sunlight, you will not get hot in space and you do not have to worry about thermal cycles.

      • Good point about the color white helping with thermal cycling and stress.

        Perhaps they can cover it with diffraction grating -- diffract the reflected light instead of reflecting a significant portion in a single direction. That way instead of a bright white object the astronomers would see a flying rainbow, or at best a single color depending on the angle.

        • Re: Huge antenna (Score:4, Interesting)

          by saloomy ( 2817221 ) on Saturday December 03, 2022 @04:27AM (#63098714)
          I think ground based observatories are going to be of less and less importance as our access to space increases by lower mass to orbit. I would trade the now blinded ground telescopes for new telescopes in orbit anyway, which would have clearer views of the objects we want to see, and wont come at a cost of a more interconnected civilization. It is a good trade off. It is a self correcting problem. Cheaper access to LEO, more obscuring satellites. Cheaper access to orbit, better space based telescopes seeing further than ground ones ever could.
          • clearly you are not an astronomer. ground based telescopes are far more cost effective than space based scopes. at the very least, the are cheaper to deploy, faster (weeks/months vrs decades) to deploy and they can be repaired. if JWT pops a fuse, I do not think anyone will go on a service call.

            There is a lot long-duration research happening using 16"-40" telescopes. Many of these scopes have been around for decades and are constantly repurposed as research and technology changes what/how we observe. R
            • Clearly, you failed reading comprehension. My point was space based telescopes will dramatically fall in cost, and increase in availability as the cost to orbit drops. That cost to orbit is being developed partly because of these constellations. That is the whole point and benefit. That reality you just described is going to become less and less a reality as these new systems come online.
            • Build more space based telescopes that can handle the light collecting job of ground based scopes. That would solve a lot or problems. Deploy them geosynchronously or at various legrange points. Then you donâ(TM)t have to worry about light pollution, atmospheric aberrations, large costs of maintenance, and astronomers whining about anything else.

          • Re: Huge antenna (Score:4, Informative)

            by kbahey ( 102895 ) on Saturday December 03, 2022 @05:38PM (#63100084) Homepage

            I think ground based observatories are going to be of less and less importance as our access to space increases by lower mass to orbit. I would trade the now blinded ground telescopes for new telescopes in orbit anyway, which would have clearer views of the objects we want to see, and wont come at a cost of a more interconnected civilization. It is a good trade off. It is a self correcting problem. Cheaper access to LEO, more obscuring satellites. Cheaper access to orbit, better space based telescopes seeing further than ground ones ever could.

            I have seen this argument made on Slashdot before.

            However, actual telescope data contradicts it, at least for the near future ...

            Just look at a list of large aperture telescopes [wikipedia.org] around the world, and see how many of them have mirrors larger than James Webb's segmented 6.5 meter mirror. Also check this visual representation of mirror sizes [wikipedia.org]. Webb and Hubble are in the lower left corner.

            Make sure you check the "future telescopes" section in the first link as well.

            We can't launch single mirrors larger than Hubble's 2.4 meter mirror unless we do the very complicated and expensive gymnastics that Webb had to do.

            Some are technically impossible (large single-segment mirrors, and mirrors that are made of segments that can't fit in an Ariane fairing). Others will be cost and time are prohibitive (just look at how much Webb cost, and how long it took). Even cutting cost and time in half, they will still be expensive ...

            We can't launch that many telescopes in space. A select few perhaps, but not all the extant and planned ones ...

            Maybe several decades in the future technology will allow some scopes to be assembled in low orbit, or something ...

            • Imagine the possibilities when Starship Cargo comes online. You know what the primary funding for that is? The constellations astronomers complain about. You know how big the fairing is on Starship is 9m X 18m! That is way better that Arianes 4.5m. As the cost also plummets, the frequency of new telescopes will be higher, as will be their complexity.

              • Re: (Score:2)

                by kbahey ( 102895 )

                You know what the primary funding for that is? The constellations astronomers complain about.

                The professional astronomers are complaining because the negative impact of satellite constellations is real [iau.org] and is impacting observations that further the progress of science and our understanding of the universe.

                (That link is from the International Astronomical Union, IAU).

                And that impact is happening now, and for the foreseeable future.

                We can't just tell several branches of science (cosmology, planetary science,

                • No disrespect to cosmologists and astronomers. Their contributions to science and physics is great but their overall impact on whatâ(TM)s happening down on earth has been abysmally small. There is nothing that a cosmologist will miss in one piece of sky that they couldnâ(TM)t see in another. The idea that what they do is somehow relevant to human life is a misnomer. They forward science and the principals of light based physics, but beyond that they offer nothing else but ways to glean subsidy mo

      • Could you use this [newscientist.com] or would the outer paint layer cook off?

      • A better approach would be cover all exposed area with photovoltaics. This would then power the satellite with waste power simply radiated away with a conventional transmitter beam.

        Where not possible an irregular non-planar specular reflective surface material would reduce glare.

  • Sun has the greatest apparent brightness when viewed from Earth surface and if there was a brighter satellite, I would be concerned. Likewise, for other stars, there is no way the satellite would have the greatest apparent brightness from the same distance.

    • ask Google (Score:1)

      by Anonymous Coward

      Likewise, for other stars, there is no way the satellite would have the greatest apparent brightness from the same distance.

      Do you even know what apparent brightness means?
      Try Googling the tricky bits before posting.

    • Re: (Score:2)

      by quenda ( 644621 )

      Even not counting Sol, the brightest star (at magnitude -1.5) Sirius is ten times as bright as 1.0 magnitude.

    • Re: (Score:2)

      by ceoyoyo ( 59147 )

      There are several brighter satellites. The space station is around -0.5 and the big American spy satellites (Germany has one too) are around 0.

  • From a scientific standpoint. Astronomers have been creating their own stars [wikipedia.org] for some time. While clearly not the same, the idea would be for the scientific community to have some input on construction (corner cubes [wikipedia.org], reflective coatings &c) such that some use could be made of these objects.

    From an aesthetic standpoint, yeah it could be detrimental having artificial sources up there. That being said, Iridium flares got as bright as -8 and they were stunning.

    • From an aesthetic standpoint, yeah it could be detrimental having artificial sources up there. That being said, Iridium flares got as bright as -8 and they were stunning.

      No, more than just aesthetics. And yes astronomers complained about iridium flares too and the newer generation of satellites also don't flare.

    • Years ago I had software that would predict Iridium flares in my area. One night I took my young son out into the yard about an hour after sunset and told him I was going to perform the ultimate magic trick (he was really into magic at the time). I pointed toward the sky, started chanting some new age sounding mumbo jumbo, and then the extremely bright Iridium flare happened. LOL the look on his face was priceless. I let him wonder about that for a weeks before finally revealing my magician's "secret". Hey,

  • As bright as the brightest stars (Score:5, Funny)

    by 93 Escort Wagon ( 326346 ) on Saturday December 03, 2022 @04:05AM (#63098692)

    "According to the International Astronomical Union, post-deployment measurements showed that BlueWalker 3 had an apparent visual magnitude of around 1 at its brightest, which is nearly as bright as Antares and Spica, the 15th and 16th brightest stars in the night sky."

    What? You can't be Sirius.

  • If they cannot handle a dot in a predictable location, how do astronomers deal with clouds, birds, and bats? We’re in the 21st century man, telescopes should be in space. Besides, they are not even letting us build large telescopes anymore. Have you guys not been following the Thirty Meter Telescope debacle? The only prime location for telescopes is space or on the moon.

    • Hehe...caltech folded like an umbrella and actually took down one of their older infrared telescopes on top of the mountain as a show of good faith.

      Fat lot of good it did anybody.

      Retards all around.

    • Agreed we should be building on the moon. Not only does that eliminate the light pollution, but the far lower gravity would allow you to produce a single mirror far larger than could be achieved on Earth.

      (Mind you, multi-mirror systems limit the advantages, although you wouldn't need to contend with edge effects with a single mirror.)

      What's more, although there are moonquakes, they're unlikely to be on the scale telescopes in Hawaii must have to contend with.

      The main problem is the fine silica dust, that wo

  • Million things to whine about as far as "light pollution" There's also a radio tower near me that looks like the brightest strobe light I've ever seen. Its 4:22am, almost pitch black outside, but every time that strobe lights, it I can see the buildings like lightning lighting up the area

    • Million things to whine about as far as "light pollution"

      Not really. Astronomers don't typically setup their telescopes in the middle of a city. There are plenty of places in the world with effectively zero light pollution leaving the only form of pollution the damn things which whiz around in the sky.

  • 65 Square meters? This is a two dimensional thing?

    Then: one third of tennis court. Couldn't find anything that matches exactly?

  • Why not require satellites to be as non-reflective as possible? Matte surfaces and dark colors would help a lot.

  • Dear/. Editors (Score:4, Interesting)

    by JoeRobe ( 207552 ) on Saturday December 03, 2022 @07:21AM (#63098850) Homepage

    The /. summary is a copy/paste of about 2/3 of the actual article linked to in the summary. Why not just paste the whole thing and not call it a summary? This is bringing the standard - nobody is actually summarizing anymore, just pasting a chunk of the article.

    Can we get back to summaries actually being a small fraction of the original story? Maybe a maximum number of sentences, or 1 paragraph?

    • Speaking for myself only, it's gotten so hard to get a story accepted to this site that there is absolutely no sense in doing a good job on the submission.

  • The thing may be big, but it also flies very low. 550 km altitude (http://n2yo.com/satellite/?s=53807).

    From the equatorial-ish regions where most serious astronomy takes place, something that low is only potentially sunlit for an hour or two around dusk and dawn, and is totally eclipsed by the earth otherwise during the rest of the night when telescopes would be operating.

    The astronomers should know this.

    My supposition is that "evil corporation pollutes the sky!" gets more clicks and retweets and leftie str

    • This one satellite may only be sunlit for an hour or two. Put up 10 more just like it, or a hundred, then what fi you have?

      • Re: (Score:1)

        by Anonymous Coward

        Put up 10 more just like it, or a hundred, then what fi you have?

        Then you have 10, or a hundred, all of which would only be visible near the horizon for an hour or two.

  • If aliens do try to contact us, this is the perfect tool to censor such communications. Just transmit over the aliens with a more powerful emittor

  • Ground observatories (Score:3)

    by Voice of satan ( 1553177 ) on Saturday December 03, 2022 @10:14AM (#63099070)

    The next EELT will have an aperture of 39 meters and will weigh 2800 tonnes. It will have 15 times the resolving power of Hubble. 0.005 arcseconds. That means its images will have a precision no space telescope can match. There is no way of building such massive instruments in space or on the far side of the moon.

    Besides the far side of the moon is baked in sunlight half of the time and would be unusable for space observations then. The EELT will have 320 nights of observations per year.

  • It's not brighter than stars. It's not emitting more radiation than any star in the night sky. It's not sending more light to the Earth than the sun. By any definition of brightness, the headline would have to be written by a mental retard.

    • Re: (Score:2)

      by ceoyoyo ( 59147 )

      It is sending more light to Earth than all but a few of the brightest stars. That is, more than the vast majority of them.

  • Seems easy. (Score:3)

    by jd ( 1658 ) <imipak@[ ]oo.com ['yah' in gap]> on Saturday December 03, 2022 @10:36AM (#63099094) Homepage Journal

    Russia needs hard currency and has satellite killers. This seems very resolvable.

  • "satellite measures nearly 65 square meters" World's first 2-dimensional satellite.

Slashdot Top Deals

Success is something I will dress for when I get there, and not until.

Close