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ESA Approves Gravitational-Wave Hunting Spacecraft For 2034 (newscientist.com)

Posted by BeauHD on from the red-light-green-light dept.

The European Space Agency has approved the Laser Interferometer Space Antenna mission designed to study gravitational waves in space. The spacecraft is slated for launch in in 2034. New Scientist reports: LISA will be made up of three identical satellites orbiting the sun in a triangle formation, each 2.5 million kilometers from the next. The sides of the triangle will be powerful lasers bounced to and fro between the spacecraft. As large objects like black holes move through space they cause gravitational waves, ripples which stretch and squeeze space-time. The LISA satellites will detect how these waves warp space via tiny changes in the distance the laser beams travel. In order to detect these minuscule changes, on scales less than a trillionth of a meter, LISA will have to shrug off cosmic rays and the particles and light from the sun. The LISA Pathfinder mission, a solo probe launched in December 2015, proved that this sensitivity was possible and galvanized researchers working to realize the full LISA mission.

49 comments

  1. Declining intelligence of Slashdot users by Anonymous Coward · · Score: 0, Offtopic

    It's been an hour and nobody has commented on this. I suppose discussing science is too difficult, so Slashdot users would prefer to stick to arguing about Trump, partisan politics, and global warming denial. This site is truly a pathetic shadow of what it once was.

    1. Re:Declining intelligence of Slashdot users by Anonymous Coward · · Score: 0

      Seems slashdot is just as susceptible to anti-intellectualism as anywhere.

      Ars still has an intelligent commenting crowd. Much, much, better than here.

    2. Re:Declining intelligence of Slashdot users by behrooz0az · · Score: 1

      I don't beleive the users have become retarded as much as you think they have. It's just that the scientific articles, at least the real ones are becoming extremely specific and focused and small topics that not many people, even smart ones are quallified to actually comment on how right or wrong they are.
      We just read and enjoy the cool acronyms and TFA pictures.
      oh, and fuck trump while we're at it.

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    3. Re:Declining intelligence of Slashdot users by Anonymous Coward · · Score: 2, Insightful

      So a comment about wibbly wobbly timey wimey laser beams would go down well..?

    4. Re:Declining intelligence of Slashdot users by Anonymous Coward · · Score: 0

      What can we say, the most exciting scientific projects come from the EU and China. The US is becoming more and more irrelevant by the day. Well that's what you get from having voted declared anti-science politicians in Congress for the last generation or so.
       

    5. Re:Declining intelligence of Slashdot users by j-b0y · · Score: 1

      Slashdot has become a desolate wasteland, just like much of the general interest part of the internet. Specialist forums are still fine.

      Wait. Slashdot has always been a desolate wasteland, it was just a much more enjoyable wasteland.

      "Reasonable arguments beget angry screeching" - Plague of Gripes

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    6. Re:Declining intelligence of Slashdot users by Anonymous Coward · · Score: 0

      It's dumbing down also.

      I don't know why the parent is at -1. As a long time reader, probably one of the longest, it is very true. This used to be one of the most visited sites on the web

    7. Re: Declining intelligence of Slashdot users by Anonymous Coward · · Score: 0

      That was a long time ago, when the masses were still confined to yahoo, aol and MSN.

    8. Re:Declining intelligence of Slashdot users by Big+Hairy+Ian · · Score: 0

      I only just saw the article. I'm just concerned that the satellites will be extremely close to the sun.

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      Build a Man a Fire, and He'll Be Warm for a Day. Set a Man on Fire, and He'll Be Warm for the Rest of His Life.

    9. Re:Declining intelligence of Slashdot users by Bender+Unit+22 · · Score: 1

      OMG, you're right. I'll start.

      There's something wrong about this article, How are they going to orbit the sun, isn't it flat like earth?
      We have already established that the moon are a hologram, so naturally they can't orbit that.

    10. Re:Declining intelligence of Slashdot users by ceoyoyo · · Score: 1

      The working scientists and seriously knowledgeable amateurs who hung out here in the late 90s have mostly moved on. Slashdot was invaded by the masses just like everything else on the web.

    11. Re: Declining intelligence of Slashdot users by KGIII · · Score: 1

      /. was never good.

      --
      "So long and thanks for all the fish."
    12. Re:Declining intelligence of Slashdot users by Anonymous Coward · · Score: 0

      Speaking of "used to", from the article:

      Following selection, the mission design and costing can be completed. Then it will be proposed for 'adoption' before construction begins. Launch is expected in 2034.

      it used to be that we knew the cost of things _before_ we selected them. Then we told everyone how much stuff would cost. And then after construction completed, we all got outraged at the cost over-runs.

      Now we just bow to the gods of "science" and ship our money to the 1%.

  2. Need this kind of thing to see pre-CMB by Maritz · · Score: 4, Funny

    First 300k or so years of this universe was opaque to light, but not to gravitational waves (obviously). So we need these kinds of 'telescope' to see earlier than 300k years or so. Cool mission. Will be interested to see if the Brits are involved or if they're still too busy disappearing up their own arses. Time will tell.

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    1. Re:Need this kind of thing to see pre-CMB by locater16 · · Score: 1

      I was wondering why it had been approved. So far as I know the first detector was built just to prove the theory. It's such a miniscule effect though that I wonder how effective it'll be.

    2. Re:Need this kind of thing to see pre-CMB by ivano · · Score: 2

      Luckily (or unluckily) the UK's involvement with the ESA is independent from the EU discussions, AFAIK

  3. Why are they waiting 17 years? by He+Who+Has+No+Name · · Score: 1, Interesting

    The changes in cost to orbit per pound just in the last two years have been game-changing. For all we know in 17 years Elon is going to be negotiating their payload fees from his HQ compound built into the side of the Mariner Valley.

    Get the lead out a little, ESA.

    1. Re:Why are they waiting 17 years? by j-b0y · · Score: 3, Informative

      Because the technology involved will take some time to develop. You have to have 2 spacecraft pointing a laser at another spacecraft 2,500,000 kilometers away, and measure the change in distance between the two arms to an incredible precision. That's... not easy.

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    2. Re:Why are they waiting 17 years? by techno-vampire · · Score: 1

      If I read TFS correctly, they're planning on having three spacecraft with each pointing lasers at the other two. If I'm right, that gives you six sets of data to work with instead of the two that your way does, making it easier to correct for the inevitable station-keeping issues. Alas, even if this goes off on schedule, I'll be in my mid-80s when it launches and I'll be very lucky if I survive long enough to see any results. Still, it sounds like a great idea and I hope they pull it off.

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    3. Re:Why are they waiting 17 years? by avandesande · · Score: 1

      In the 80s I used to walk by one of the LIGO prototypes at Caltech. Gravity waves take a long time to transverse the universe, and it takes a long time for us to detect them!

      --
      love is just extroverted narcissism
    4. Re:Why are they waiting 17 years? by Immerman · · Score: 1

      Depending on how you count it, it's actually 6 spacecraft, specifically to eliminate the vast bulk of station-keeping issues. Each of the three nodes is actually two separate craft, one nested inside the other, without making any contact, in a "zero-drag satellite" configuration.

      The inner craft contains all the measuring equipment, laser emitters, etc, and is only influenced by gravity. The outer "shell" is there specifically to enable the "only influenced by gravity" orbital path - it intercepts the solar wind, photon pressure, etc. before they can reach the inner craft, and then continuously makes tiny corrections to its orbit in order to remain centered on the inner craft.

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    5. Re: Why are they waiting 17 years? by Anonymous Coward · · Score: 0

      Nope, all measurement equipment (Lasers, telescopes interferometers etc) does actually sit on the "outer spacecraft". The "inner spacecraft" consists only of a test mass in free-fall. The "outer spacecraft" measures the position of the test mass within itself very accurately, and actively positions itself to keep its position relative to the test mass constant using micro-thrusters, thus mimicking the perfect free-fall of the test-mass. This trick to effectively compensate all external forces like solar wind etc was tested on LISA Pathfinder.

    6. Re: Why are they waiting 17 years? by Immerman · · Score: 1

      Are you sure? I could swear I read the opposite.

      Such an approach would certainly make sense for the solitary proof-of-concept Pathfinder, but I would think that it would introduce an unacceptable amount of noise to the laser interferometers planned for LISA itself.

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    7. Re: Why are they waiting 17 years? by Anonymous Coward · · Score: 0

      Yep, 100% positive.
      The Drag Free Attitude Control System tested on LISA Pathfinder was validating the concept for LISA, that was one of the major reasons to fly LPF. Actually, the DFACS tested on LPF was more complex than the one on LISA will be: LPF had two test masses on one satellite, which results in way more degrees of freedom to control, without more actuators... Effectively, you can't control the distance between the test masses by flying around them, so you had to apply some controlled force on one of them, introducing extra noise. Still, LPF performance exceeded its requirements quite a bit, actually meeting or exceeding even most LISA noise requirements.

      The extra noise you're talking about cannot be avoided but has to be designed around: due to solar wind, photon pressure and loads of other external forces, the microthrusters have to be continuously firing. In order to limit the noise you're mentioning, they can be throttled with 0.1uN resolution.

      https://www.elisascience.org/articles/elisa-mission/drag-free-operation
      https://www.cosmos.esa.int/web/lisa-pathfinder/dfacs

  4. They cancelled it back in 2012 by Laxator2 · · Score: 1

    LISA was in development for quite a few years (10 maybe ?) when it was cancelled.
    Now that LIGO did find evidence for gravitational waves ESA wants to be at the winner's table, so the bad project is good again.

    I think we should call that "having a vision".

    1. Re:They cancelled it back in 2012 by Anonymous Coward · · Score: 0

      No, it was someone proving that gravitational waves exit that was the decider.

      Big difference between punting a lot of money on something that may or may not exist at all, and a certainty.

    2. Re:They cancelled it back in 2012 by Anonymous Coward · · Score: 2, Informative

      LISA was started as a joint ESA-NASA mission.
      Only NASA cancelled their participation in 2011 because of budget
      Since then it has been an ESA mission - and it had the support of the agency (reaffirmed in 2013 in the "cosmic vision" mission selection).

      So it was never a "bad project" for ESA - you could say the US congress is lacking vision if they reduce NASA's budget so they can't afford missions like that anymore....

    3. Re:They cancelled it back in 2012 by j-b0y · · Score: 5, Informative

      LISA was cancelled because JWST was eating the NASA astrophysics budget; ditto IXO cancellation. LISA survived in a much reduced form as NGO, and IXO as ATHENA.

      There wasn't any real chance of LISA scooping LIGO/E-LIGO if gravitational waves were really detectable, but the sensitivity of LISA will open up detection of many more classes of GW emitters.

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    4. Re:They cancelled it back in 2012 by Anonymous Coward · · Score: 0

      Wikipedia says:

      The high cost and the delays in its release date contributed to the Lisa's demise

      in 1986

      https://en.wikipedia.org/wiki/Apple_Lisa#The_end_of_the_Lisa

    5. Re:They cancelled it back in 2012 by Anonymous Coward · · Score: 1

      Actually it is the very long distance between the satellites that will open up detection of many more classes of GW events, not so much the sensitivity. GW detectors are essentially antenna and the longer distances tune it for much lower frequencies, and thus a different class of events.
      For high frequencies events, like the colliding black holes LIGO detected, the Crests and Troughs of the gravity wave will mostly cancel each other out over the length of the detection path making detection actually harder.

    6. Re:They cancelled it back in 2012 by kiminator · · Score: 2

      The reduced noise from not being near the ground is also a big bonus. But yes, the difference in detection frequencies is the most significant difference.

  5. This is a fatally flawed experiment by Anonymous Coward · · Score: 1

    A triangular formation of 3 probes? Seriously? What's needed, bare minimum, is a suite of 4 probes in a tetrahedonal configuration. That way, we get a much more accurate vector reading for the event. They cannot be defeated, we need to know what direction to run!

    1. Re: This is a fatally flawed experiment by Anonymous Coward · · Score: 0

      How would you keep a tetrahedron even approximately stable, when all the parts are in orbit? Think about it.

    2. Re: This is a fatally flawed experiment by Anonymous Coward · · Score: 0

      I would suggest thrusters and maths...

    3. Re:This is a fatally flawed experiment by Anonymous Coward · · Score: 0

      I think the "triangle" (3 probes) they're planning will be on the same plane as the planets. Getting stuff off that plane, and having it be in stable formation with the rest of the probes would be very costly fuel wise.

    4. Re: This is a fatally flawed experiment by Immerman · · Score: 1

      No good - every time you fire your thrusters, even miniscule-thrust ion drives, you're introducing chaotic noise many orders of magnitude larger than the signal you're trying to detect. And any time you're *not* firing your thrusters, the satellites are immediately drifting out of alignment. To get the needed precision they're actually using a "zero drag" satellite-within-a-satellite design so that the free-floating inner satellite is only influenced by gravity, while the outer one is a shell designed to take the signal destroying "hits" from the solar wind, photon pressure, etc. and then correct it's orbit to remain centered around the free-falling inner one.

      Just getting three satellites into a stable equilateral arrangement is a fine trick of celestial mechanics - each satellite orbits the sun in a different plane, resulting in an stable equilateral "tumbling triangle" of orbits. https://en.wikipedia.org/wiki/...

      And incidentally, while the current gravity-wave detectors are only large enough to detect the high-frequency signals of merging black holes, the LISA is designed specifically to detect lower-frequency signals such as extremely large binaries and other such phenomena, which should be giving off a fairly stable signal. And a stable signal, combined with the tumbling of the array, should allow for fairly accurate 3D directional resolution as the signal fades in and out based on alignment.

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    5. Re:This is a fatally flawed experiment by Immerman · · Score: 1

      Not quite - their combined center of mass will follow Earth in its orbit, but each satellite orbits in a different plane so that they form a tumbling triangle.(animation: https://en.wikipedia.org/wiki/... )

      I think if you tried to get them into the same plane you would need to have far more eccentric out-of-phase orbits, meaning far larger built-in "noise" (and thus less sensitivity) as their relative distances and speeds continuously varied.

      Alternately you could place them all equidistantly around the sun in the same circular orbit - but then the triangle would be too large to detect the signals we're interested in - such as galactic and 10^6 solar-mass binaries (the bigger the detector, the lower the frequency of the signals it can detect) Similarly, the largest stable orbit achievable around Earth is too small and can only detect higher-frequency signals (plus, we've got the Moon to deal with, which destabilizes the entire orbital neighborhood)

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    6. Re:This is a fatally flawed experiment by avandesande · · Score: 1

      This doubles the number of optical components and likely the cost.

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    7. Re:This is a fatally flawed experiment by kiminator · · Score: 1

      Nah, the construction cost of the satellite itself isn't all that important, not compared to the launch cost. The other commenters have it right: it's about orbital mechanics. You can organize the satellites in a triangle so that they maintain the same shape. I don't think it's possible to add a fourth satellite and keep it in an orbit that's actually stable.

      I don't think that a fourth satellite would improve the science all that much anyway.

    8. Re: This is a fatally flawed experiment by Anonymous Coward · · Score: 0

      Suggest something else. The maths tell you that thrusters can't ever do the job.

    9. Re:This is a fatally flawed experiment by avandesande · · Score: 1

      While I agree that the orbital considerations are most important, I think you are way off on cost. Are you even aware of the components that go into these lasers? This system is amazingly complex. The budget right now is 2.4 billion dollars, surely that isn't mostly launch costs.

      --
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  6. Useful by Anonymous Coward · · Score: 0

    I'm sure that by 2034 the New Europeans will find this information intriguing even as they burn down libraries, museums and laboratories chanting "Allahu akbar".

    1. Re: Useful by tigersha · · Score: 1

      Like they say in Game of Thrones: I swear by the old Gods and the new that won't happen

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  7. metric system by iridium_ionizer · · Score: 2
    From summary:

    In order to detect these minuscule changes, on scales less than a trillionth of a meter

    I think these are called picometers (10^-12 m)

  8. 2034? Really? by Nova+Express · · Score: 0

    President John F. Kennedy announced the goal of "landing a man on the Moon and returning him safely to the Earth" on May 25, 1961, and Apollo 11 landed on the moon July 20, 1969.

    So Europe plans to take twice as long as the entire Apollo program took to get to the moon to launch three unmanned probes.

    All of this is just moonbeams anyway. By 2034, Europe will be too broke to pay for space probes...

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    1. Re:2034? Really? by Anonymous Coward · · Score: 0

      President John F. Kennedy announced the goal of "landing a man on the Moon and returning him safely to the Earth" on May 25, 1961, and Apollo 11 landed on the moon July 20, 1969.

      So Europe plans to take twice as long as the entire Apollo program took to get to the moon to launch three unmanned probes.

      All of this is just moonbeams anyway. By 2034, Europe will be too broke to pay for space probes...

      Do you think that the US is any different when it comes to funding space stuff or science in general? Especially now, with the Orange One running things? When the EPA dude think climate change is BS?

      Really? You're going to make that comparison?