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.