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Tiny satellites could be 'guide stars' for huge next-generation telescopes: Researchers design CubeSats with lasers to provide steady reference light for telescopes investigating distant planets (MIT)
NASA engineers are now developing designs [for] next-generation space telescopes, including "segmented" telescopes with multiple small mirrors that could be assembled or unfurled to form one very large telescope once launched into space.
[...] One challenge for segmented space telescopes is how to keep the mirror segments stable and pointing collectively toward an exoplanetary system. Such telescopes would be equipped with coronagraphs -- instruments that are sensitive enough to discern between the light given off by a star and the considerably weaker light emitted by an orbiting planet. But the slightest shift in any of the telescope's parts could throw off a coronagraph's measurements and disrupt measurements of oxygen, water, or other planetary features.
Now MIT engineers propose that a second, shoebox-sized spacecraft equipped with a simple laser could fly at a distance from the large space telescope and act as a "guide star," providing a steady, bright light near the target system that the telescope could use as a reference point in space to keep itself stable.
In a paper published today in the Astronomical Journal, the researchers show that the design of such a laser guide star would be feasible with today's existing technology. The researchers say that using the laser light from the second spacecraft to stabilize the system relaxes the demand for precision in a large segmented telescope, saving time and money, and allowing for more flexible telescope designs.
"This paper suggests that in the future, we might be able to build a telescope that's a little floppier, a little less intrinsically stable, but could use a bright source as a reference to maintain its stability," says Ewan Douglas, a postdoc in MIT's Department of Aeronautics and Astronautics and a lead author on the paper.
Laser Guide Star for Large Segmented-aperture Space Telescopes. I. Implications for Terrestrial Exoplanet Detection and Observatory Stability (DOI: 10.3847/1538-3881/aaf385) (DX)
(Score: 1, Interesting) by Anonymous Coward on Saturday January 05 2019, @08:51PM (5 children)
Send up 100s of tiny satellites, each nothing more than a "mirror", with a singe (or multiple)0 base satellite with the receiver/camera and a second acting as a sun-shield. Then you create assortment of mirror sizes. You can keep sending more and more building super sized telescopes that could be measured in miles.
If that is not a way to go, then...
100s of small of shelf short barrel telescopes 6" or 8", a couple hundred per. Bolt on a react action wheel and nav... and again a super-size telescope. Issue here is 100's of downloads. But does allow for leaving smaller groups to work on different areas of the sky.
(Score: 4, Informative) by takyon on Saturday January 05 2019, @09:03PM (3 children)
This is like what you are talking about:
https://www.nasa.gov/directorates/spacetech/niac/2018_Phase_I_Phase_II/Modular_Active_Self-Assembling_Space_Telescope_Swarms [nasa.gov]
This one is a bit different:
https://www.nasa.gov/directorates/spacetech/niac/2018_Phase_I_Phase_II/Kilometer_Space_Telescope [nasa.gov]
However we can benefit simply by having a cheap superheavy launch capability: SpaceX's Starship. You can send up modular components with a diameter of up to 9 meters in the payload fairing, and have them assemble themselves autonomously or get astronauts to do it.
We can have a 100+ meter aperture space telescope, and it could cost less than JWST if done right. Just don't get Northrop Grumman to do it.
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(Score: 0) by Anonymous Coward on Saturday January 05 2019, @09:24PM (2 children)
Thank for the link.
What I was thinking - NO connection between the mirror segments just either independent mirrors or small independent telescopes. that can flow from on setup to the next. More like cubesats.
Think of cloud servers. Who cares where they are located or connected as long as they can come on-line in one set up or another and drop off when not needed. Using off the shelf parts and mass produced micro-controlers. We can push more and more, as extra cargo on any lunch of something bigger, or a maybe 100 on a single rocket.
Use them like the radio array in the S.W. (was in movie 'Contact') Or the telescopes being built on high plane in Chile.
That's it! Amazon creates it and rents out as needed.
(Score: 3, Informative) by takyon on Saturday January 05 2019, @10:30PM (1 child)
https://en.wikipedia.org/wiki/Astronomical_interferometer [wikipedia.org]
Radio interferometry is easy, optical interferometry is very difficult, and AFAIK has never been attempted in space. Traditional large aperture telescopes also tend to have better light collecting capability than the virtual telescope created by separate, smaller components. So an interferometer (even the radio ones) is not a substitute for all use cases of gigantic telescopes (which could see dimmer objects better).
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(Score: 1, Interesting) by Anonymous Coward on Monday January 07 2019, @10:36PM
There is no difference between an astronomical interferometer and a full aperture telescope. If you take a primary mirror and remove all the glass except for two disks out at the edge of the mirror, you get an interferometer. As you fill in more and more glass, you transition from one to the other. As you suggest, that interferometer has the resolving capability of the full mirror using only a fraction of the glass (same resolution, at least, along the line that connects the two subapertures), but you've given away its light collection capability, which goes as the areas of the glass.
There as been no shortage of proposed projects over the years to do space-based interferometry (early versions of the Space Interferometry Mission (SIM) [wikipedia.org] and the Terrestrial Planet Finder [nasa.gov], as two examples). It hasn't been done yet, largely because it is really technically challenging.
(Score: 2) by The Mighty Buzzard on Sunday January 06 2019, @04:45AM
I was thinking something that would be useful for orienting satellites other than telescopes as well. No point reinventing the wheel for each one.
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