Several ways to 1000-meter space telescopes

Currently there are some 30 and 40 meter optical ground based telescopes under construction. The largest mirror for a space telescope is still the Hubble Space Telescope. The 6.5 meter James Webb telescope has been delayed. James Webb has 18 hexagon segments and weighs about 6500 kilograms.

There are about four ways 1000 meter (kilometer) scale space telescopes could be made in the next two decades.

1. Space bubble telescope
2. Self-assembled modular telescopes
3. Spider-fab in space construction
4. Giant lunar space telescope construction

Space bubble telescope

Devin Crowe gave an update on the NASA NIAC study on one-kilometer space bubble telescopes.

The plan is bring liquid and gas and blow a large spherical bubble and then shine a wavelength to solify the material. They would spray part of the bubble with a very thin metal layer to make a reflective telescope.

They have simulated that a one-kilometer telescope would be able to image Jupiter and its four largest moons from a distance of 7 parsecs.

There has been work done with one meter metalized glass spheres as a telescope in the stratosphere. There is follow up work for a ten meter metalized mylar sphere as a telescope.

A cubesat would be able to hold the bubble liquid and gas to inflate a 2-meter diameter metalized sphere.

They would want to create a 30-meter space bubble telescope and then a 100-meter and then a 1000-meter space telescope.

Self-assembly of modular space telescope

Cornell University has a NASA NIAC study for a fully modular self-assembled massive space telescope. They are taking mirrors segments based on the current James Webb space telescope mirror segments and then adding in some adjustments so that each piece can function in any random location. They also add solar sails and velcro attachments so that the modules with solar sails can come in contact and stick together. After the object settle then they use magnets to creep into the exactly the correct position to fit together for a larger telescope mirror. The solar sail would be detached and tethered as a sunshade.

800 some modules could form a 30-meter space telescope. Such a telescope would be able to image the surface of an exoplanet and differentiate between a world with a supercontinent or with other continent distributions.

8000 some modules would form a 100-meter space telescope. 80,000 modules could form a 1000-meter space telescope.

They have determined the best orbit to assemble the modules. It is an orbit with some complexity but with the benefit that modules would bump into each other at low speeds.

Spider Fab

Spiderfab was presented at the Future in space Operations workshop.

• SpiderFab architecture combines robotic assembly with additive manufacturing techniques adapted for space
• On orbit fabrication enables order.of.magnitude improvements in packing efficiency and launch mass for large systems
>Higher Power, Resolution, Sensitivity and Bandwidth
• On.orbit fabrication with SpiderFab will enable NASA to accomplish 10X more science.per.dollar
• NIAC and SBIR work has validated feasibility of the key processes for SpiderFab
• They are preparing technology for flight demonstrations
• Affordable pathfinder demo can create new mission capability

Rudranarayan Mukherjee, NASA JPL gave an update on progress to Robotic Assembly of Space Assets: Architectures and Technologies. This is the path to making 100 meter and even multi-kilometer diameter space telescopes and starshades in space.

The presentation was at the Future In-Space Operations (FISO) Working Group Presentations at the FISO telecon.

They are able to assemble 3-meter truss modules in the lab with robotic systems in 26 minutes

They have looked at sending robotic assembly systems to the space station and to have modular telescopes built in space.

Giant Lunar Telescope

There has been small UV-sensitive telescope on the Moon since 2013. China landed it as part of the Chang’e 3 lander.

There were studies of lunar telescopes using spinning disk of liquid with a reflective surface, lining the interior of one of the millions of bowl-shaped craters on the Moon. Such an instrument would extend for kilometers, making a gigantic “eye” to look at the universe. Liquid mirror telescopes already have been constructed on Earth.

22 thoughts on “Several ways to 1000-meter space telescopes”

  1. For use inside the solar system, the obvious new science that trumps all the four listed types of possible telescopes is METAMATERIAL FLAT SURFACE optics. The only question is scaling them up to the required size. These would be flat, a mere few atoms thick, and thus lightweight. This could also make them less prone to warping under temperature changes. They could be corrected for chromatic and spherical aberration, as has recently been demonstrated. How to scale them up would be the challenge.

    Reply
  2. Indeed. The unrealistic telescope plan came from the assumption of seeing continents in exoplanets from a space telescope near Earth, requiring country sized mirrors and budgets for their construction. That’s obviously too much. That’s what the solar gravity lenses are good for. And you don’t need to imagine continent sized features at first, just do your best to get dots of identifiable reflected light separated from that of the star, in order to know a lot about those planets. And once you have a set of interesting candidates found (warm enough for liquid water, with water and O2 detected, possibly organic matter), then you send a mission to the corresponding solar gravity focus points in the antipodes of the star(s) of interest, to get very detailed pictures of continent sized features. Then you could dream of seeing a new Earth.

    Reply
  3. Indeed. The unrealistic telescope plan came from the assumption of seeing continents in exoplanets from a space telescope near Earth requiring country sized mirrors and budgets for their construction. That’s obviously too much.That’s what the solar gravity lenses are good for.And you don’t need to imagine continent sized features at first just do your best to get dots of identifiable reflected light separated from that of the star in order to know a lot about those planets.And once you have a set of interesting candidates found (warm enough for liquid water with water and O2 detected possibly organic matter) then you send a mission to the corresponding solar gravity focus points in the antipodes of the star(s) of interest to get very detailed pictures of continent sized features.Then you could dream of seeing a new Earth.

    Reply
  4. The links didn’t work. The first link is a article titled “The Ultimate Space Telescope Would Use the Sun as a Gravitational Lens” from Air & Space magazine. The second link is from this website titled. “Getting to the outer solar system 15X faster with missions over 40 times larger

    Reply
  5. The links didn’t work.The first link is a article titled The Ultimate Space Telescope Would Use the Sun as a Gravitational Lens”” from Air & Space magazine.The second link is from this website titled. “”””Getting to the outer solar system 15X faster with missions over 40 times larger”””””””

    Reply
  6. Continents could be imaged if a telescope could be placed far enough from our sun to use gravity lensing. Here is a article from Air and Space magazine that talks about it. https://www.airspacemag.com/daily-planet/ultimate-space-telescope-would-use-sun-lens-180962499/ The hard part is getting telescopes out to around 500 to 550 AU from the sun. The current main idea is to beam power to a spacecraft that has ion engines, but this would be a fairly large undertaking. Here is a article about the power beaming idea. https://staging-nextbigfuture.kinsta.com/2018/04/getting-the-outer-solar-system-15x-faster-with-missions-over-40-times-larger.html

    Reply
  7. Continents could be imaged if a telescope could be placed far enough from our sun to use gravity lensing. Here is a article from Air and Space magazine that talks about it. https://www.airspacemag.com/daily-planet/ultimate-space-telescope-would-use-sun-lens-180962499/The hard part is getting telescopes out to around 500 to 550 AU from the sun. The current main idea is to beam power to a spacecraft that has ion engines but this would be a fairly large undertaking. Here is a article about the power beaming idea. https://staging-nextbigfuture.kinsta.com/2018/04/getting-the-outer-solar-system-15x-faster-with-missions-over-40-times-larger.html

    Reply
  8. That much is true. However, astronomers are — remarkably — satisfied with having “just a dot” separate from a star, to qualify as “direct imaging of a planet”. Dots, observed over fairly significant lengths of time give very decent estimates of stellar mass. That in turn drives astrophysics, to no small degree. Confirmation of assumptions about distance; estimates of planetary size through estimates of albedo and the absolute brightness of the wee dot. And with time, perhaps even measuring the hourly changes in brightness of the dot. As it spins on its axis. Which very, very indirectly allows something of a deconvolution map to be generated for its otherwise invisible (or rather, unresolved) surface. And with big enough telescopes, and these things called remote star shades (to block out 99.9999% of the light of the star, leaving just the planets, one hopes… ), to do spectrography on the planet(s). Which would be a MAJOR boon to astrophysics and exobiology. Are the spectroscopic markers for oxygen, carbon dioxide, sulfur dioxide, methane present? Chlorophylls and other oddities. Liquid water, water vapor absorption bands? All nature of the remote worlds’ nature can be derived from keen spectroscopy. The KEPLER mission has inferred that the majority of stars (so far) are quite a bit DIFFERENT from Ol’ Sol. They have planets aplenty, but mostly very, very close to the parent star. Thus your question could have been (in light of what I just wrote), “How big does a telescope need to be to do spectroscopy on the closest planets to the star?”. Ah, the same calculations. But this time, the distance involved is about 10,000,000 km. ¹⁄₁₅ the distance of Sol to Earth. Substituting that in gives: 63 meters. 2,500 times smaller! Or in area, well over 6 million times smaller. In fact, not even a kilometer. It is for this reason, that there is a substantial ‘push’ to build a more conventional 100 to 200 meter diameter scope in space. Its basical

    Reply
  9. That much is true.However astronomers are — remarkably — satisfied with having “just a dot” separate from a star to qualify as “direct imaging of a planet”. Dots observed over fairly significant lengths of time give very decent estimates of stellar mass. That in turn drives astrophysics to no small degree. Confirmation of assumptions about distance; estimates of planetary size through estimates of albedo and the absolute brightness of the wee dot. And with time perhaps even measuring the hourly changes in brightness of the dot. As it spins on its axis. Which very very indirectly allows something of a deconvolution map to be generated for its otherwise invisible (or rather unresolved) surface. And with big enough telescopes and these things called remote star shades (to block out 99.9999{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} of the light of the star leaving just the planets one hopes… ) to do spectrography on the planet(s). Which would be a MAJOR boon to astrophysics and exobiology. Are the spectroscopic markers for oxygen carbon dioxide sulfur dioxide methane present? Chlorophylls and other oddities. Liquid water water vapor absorption bands? All nature of the remote worlds’ nature can be derived from keen spectroscopy. The KEPLER mission has inferred that the majority of stars (so far) are quite a bit DIFFERENT from Ol’ Sol. They have planets aplenty but mostly very very close to the parent star. Thus your question could have been (in light of what I just wrote) “How big does a telescope need to be to do spectroscopy on the closest planets to the star?”. Ah the same calculations. But this time the distance involved is about 10000000 km. ¹⁄₁₅ the distance of Sol to Earth. Substituting that in gives: 63 meters. 2500 times smaller! Or in area well over 6 million times smaller. In fact not even a kilometer. It is for this reason that there is a substantial ‘push’ to build a more convent

    Reply
  10. Yep… trigonometry answers: angular separation = object dimension / baseline distance as = od / bd as = 4,000 km ÷ 100 LY as = 4×10⁶ m/s / (100 × 365.25 × 24 × 60 × 60 × 299,792,458 m/s) as = 4.22×10⁻¹² radians diameter = 1.22 λ / angular resolution &lambda = 550×10⁻⁹ m wavelength (green light) diameter = 1.22 × 550×10⁻⁹ ÷ 4.22×10⁻¹² radian diameter = 158,700 m diameter = 158 kilometers area = πR² … R = 158.7 km ÷ 2 area = 19,780 km² This would be SUBSTANTIALLY larger than the 1 km telescope(s) of this article. Substantially larger than any city on Earth. Size of a county. Or some of Europe’s smaller countries. If the price somehow scales only to the 3rd power of diameter (i.e. a bit more rapidly than the area), then this size mirror would have 4,000,000× the cost of a 1 km diameter telescope. Now granted, there is a way to make such a thing as an “airy sunflower”, or barely filled strut systems with only 1% or so of the full-scale number of mirrors in place. Cuts the cost by 100 of course. But 4,000,000 ÷ 100 → 40,000× still. Not terribly impressive. Just saying, GoatGuy

    Reply
  11. Yep… trigonometry answers:angular separation = object dimension / baseline distanceas = od / bdas = 4000 km ÷ 100 LYas = 4×10⁶ m/s / (100 × 365.25 × 24 × 60 × 60 × 299792458 m/s)as = 4.22×10⁻¹² radiansdiameter = 1.22 λ / angular resolution&lambda = 550×10⁻⁹ m wavelength (green light)diameter = 1.22 × 550×10⁻⁹ ÷ 4.22×10⁻¹² radiandiameter = 158700 mdiameter = 158 kilometersarea = πR² … R = 158.7 km ÷ 2area = 19780 km²This would be SUBSTANTIALLY larger than the 1 km telescope(s) of this article. Substantially larger than any city on Earth. Size of a county. Or some of Europe’s smaller countries. If the price somehow scales only to the 3rd power of diameter (i.e. a bit more rapidly than the area) then this size mirror would have 4000000× the cost of a 1 km diameter telescope. Now granted there is a way to make such a thing as an airy sunflower””” or barely filled strut systems with only 1{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} or so of the full-scale number of mirrors in place. Cuts the cost by 100 of course. But 40000 ÷ 100 → 40000× still. Not terribly impressive.Just saying””GoatGuy”””””””

    Reply
  12. Indeed. The unrealistic telescope plan came from the assumption of seeing continents in exoplanets from a space telescope near Earth, requiring country sized mirrors and budgets for their construction. That’s obviously too much.

    That’s what the solar gravity lenses are good for.

    And you don’t need to imagine continent sized features at first, just do your best to get dots of identifiable reflected light separated from that of the star, in order to know a lot about those planets.

    And once you have a set of interesting candidates found (warm enough for liquid water, with water and O2 detected, possibly organic matter), then you send a mission to the corresponding solar gravity focus points in the antipodes of the star(s) of interest, to get very detailed pictures of continent sized features.

    Then you could dream of seeing a new Earth.

    Reply
  13. The links didn’t work.
    The first link is a article titled “The Ultimate Space Telescope Would Use the Sun as a Gravitational Lens” from Air & Space magazine.

    The second link is from this website titled.
    “Getting to the outer solar system 15X faster with missions over 40 times larger”

    Reply
  14. Continents could be imaged if a telescope could be placed far enough from our sun to use gravity lensing. Here is a article from Air and Space magazine that talks about it. https://www.airspacemag.com/daily-planet/ultimate-space-telescope-would-use-sun-lens-180962499/

    The hard part is getting telescopes out to around 500 to 550 AU from the sun. The current main idea is to beam power to a spacecraft that has ion engines, but this would be a fairly large undertaking. Here is a article about the power beaming idea.
    https://www.nextbigfuture.com/2018/04/getting-the-outer-solar-system-15x-faster-with-missions-over-40-times-larger.html

    Reply
  15. That much is true.

    However, astronomers are — remarkably — satisfied with having “just a dot” separate from a star, to qualify as “direct imaging of a planet”. Dots, observed over fairly significant lengths of time give very decent estimates of stellar mass.

    That in turn drives astrophysics, to no small degree. Confirmation of assumptions about distance; estimates of planetary size through estimates of albedo and the absolute brightness of the wee dot.

    And with time, perhaps even measuring the hourly changes in brightness of the dot. As it spins on its axis. Which very, very indirectly allows something of a deconvolution map to be generated for its otherwise invisible (or rather, unresolved) surface. And with big enough telescopes, and these things called remote star shades (to block out 99.9999% of the light of the star, leaving just the planets, one hopes… ), to do spectrography on the planet(s). Which would be a MAJOR boon to astrophysics and exobiology.

    Are the spectroscopic markers for oxygen, carbon dioxide, sulfur dioxide, methane present? Chlorophylls and other oddities. Liquid water, water vapor absorption bands? All nature of the remote worlds’ nature can be derived from keen spectroscopy.

    The KEPLER mission has inferred that the majority of stars (so far) are quite a bit DIFFERENT from Ol’ Sol. They have planets aplenty, but mostly very, very close to the parent star. Thus your question could have been (in light of what I just wrote), “How big does a telescope need to be to do spectroscopy on the closest planets to the star?”.

    Ah, the same calculations. But this time, the distance involved is about 10,000,000 km. ¹⁄₁₅ the distance of Sol to Earth. Substituting that in gives: 63 meters. 2,500 times smaller! Or in area, well over 6 million times smaller.

    In fact, not even a kilometer.

    It is for this reason, that there is a substantial ‘push’ to build a more conventional 100 to 200 meter diameter scope in space. Its basically “just the right size” to reach out to about 250 light years, and still (with a suitable star shade) resolving enough to directly measure planets of even the closest varieties around them.

    Likewise, if “fully filled” (i.e. a ‘conventional’ mirror), it’d pick up PRODIGIOUS amounts of light. Plenty to do spectroscopy in both the IR, visible and UV bands. Quite the instrument. A huge astrophysics resource.

    Keep on wishing!
    Just saying,
    GoatGuy

    Reply
  16. Yep… trigonometry answers:

    angular separation = object dimension / baseline distance
    as = od / bd
    as = 4,000 km ÷ 100 LY
    as = 4×10⁶ m/s / (100 × 365.25 × 24 × 60 × 60 × 299,792,458 m/s)
    as = 4.22×10⁻¹² radians

    diameter = 1.22 λ / angular resolution
    &lambda = 550×10⁻⁹ m wavelength (green light)
    diameter = 1.22 × 550×10⁻⁹ ÷ 4.22×10⁻¹² radian
    diameter = 158,700 m
    diameter = 158 kilometers

    area = πR² … R = 158.7 km ÷ 2
    area = 19,780 km²

    This would be SUBSTANTIALLY larger than the 1 km telescope(s) of this article. Substantially larger than any city on Earth. Size of a county. Or some of Europe’s smaller countries.

    If the price somehow scales only to the 3rd power of diameter (i.e. a bit more rapidly than the area), then this size mirror would have 4,000,000× the cost of a 1 km diameter telescope.

    Now granted, there is a way to make such a thing as an “airy sunflower”, or barely filled strut systems with only 1% or so of the full-scale number of mirrors in place. Cuts the cost by 100 of course. But 4,000,000 ÷ 100 → 40,000× still.

    Not terribly impressive.
    Just saying,
    GoatGuy

    Reply

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