Science

Judi Lynn

(160,678 posts) Sun Jan 6, 2019, 02:08 AM Jan 2019

Tiny satellites could be 'guide stars' for huge next-generation telescopes

January 04, 2019

There are more than 3,900 confirmed planets beyond our solar system. Most of them have been detected because of their "transits" -- instances when a planet crosses its star, momentarily blocking its light. These dips in starlight can tell astronomers a bit about a planet's size and its distance from its star.

But knowing more about the planet, including whether it harbors oxygen, water, and other signs of life, requires far more powerful tools. Ideally, these would be much bigger telescopes in space, with light-gathering mirrors as wide as those of the largest ground observatories. NASA engineers are now developing designs for such 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.

NASA's upcoming James Webb Space Telescope is an example of a segmented primary mirror, with a diameter of 6.5 meters and 18 hexagonal segments. Next-generation space telescopes are expected to be as large as 15 meters, with over 100 mirror segments.

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.

More:
https://www.brightsurf.com/news/article/010419473344/tiny-satellites-could-be-guide-stars-for-huge-next-generation-telescopes.html

1 replies

= new reply since forum marked as read

Highlight:

Tiny satellites could be 'guide stars' for huge next-generation telescopes (Original Post) Judi Lynn Jan 2019 OP

Laser CubeSats could become artificial stars to keep space telescopes focused Judi Lynn Jan 2019 #1

Judi Lynn

(160,678 posts)

1. Laser CubeSats could become artificial stars to keep space telescopes focused

Reply to Judi Lynn (Original post)

Sun Jan 6, 2019, 04:47 AM

Jan 2019

SPACE
David Szondy
4 hours ago

NASA is poised to send larger and larger telescopes into space over the next couple of decades and a team of researchers at MIT is working out how to use CubeSats to keep them fixed on target. Using lasers, the bread-loaf sized spacecraft will serve as artificial guide stars to act as points of reference and make sure the giant scopes are tracking and focusing properly.

Since it was launched in 1990, NASA's Hubble space telescope has returned an incredible gallery of images, not to mention volumes of data that will keep scientists busy for generations. However, its 2.4-m (8-ft) mirror will be dwarfed by the James Webb Space Telescopes' 6.5-m (21-ft) mirror made of 18 hexagonal segments and the next-generation telescopes that will have 100 segment mirrors measuring up to 15 m (49 ft).

This jump in size will provide researchers with unprecedented power to probe deep into space and to carry out such specialized operations as not only seeking out exoplanets, but also making direct, detailed observations of their atmospheres. However, this magnifying power also requires an extremely high level of precision to make sure the telescope is pointed in the right direction and that it is properly focused. Otherwise, you end up with a multi-billion dollar equivalent of taking a snapshot of your own thumb.

It's a problem that earthbound astronomers, both amateur and professional, have grappled with ever since some clever person figured out how to mount a camera on a telescope. Doing so turned the telescope into a tremendously important instrument, but it also meant that the scope had to be kept very stable and pointed in exactly the right spot for minutes or even hours at a time to get the correct exposure

More:
https://newatlas.com/laser-cubesat-space-telescopes/57889/

Reply to this discussion