The launch of the much-anticipated James Webb Space Telescope may keep getting delayed, but its successor could be sent into space in multiple launches over a period of months or years. A team of 15 scientists, led by Cornell University assistant professor of mechanical and aerospace engineering Dmitry Savransk, has presented a proposal to NASA for a series of small satellites that would rendezvous in space and assemble into a telescope nearly 100 ft (30 m) across.

As space science progresses, space telescopes have grown in size. The Hubble telescope's mirror has a diameter of 2.4 m (7.8 ft) and the JWST's is 6.5 m (21 ft) wide. These instruments and others like them have done much to expand our knowledge and appreciation of the universe, but they are delicate and temperamental devices that are often notable for cost overruns, design flaws, and delayed launches.

So far, NASA has been willing to live with this, but the next-generation telescopes will be so big that launching them in one piece may not be feasible – much less making sure that they are operational.

Receiving Phase I funding through NASA's Innovative Advanced Concepts (NIAC) program, Savransky's idea is to simplify the construction of giant space telescopes for exoplanet surveys by abandoning the one-piece design in favor of a modular system made up of one-meter-wide (3-ft) hexagonal modules, each topped by an edge-to-edge adjustable mirror. The idea is that these modules would act as hitchhikers on other payload launches as space becomes available.

Once in Earth orbit, the modules would deploy solar sails and use the solar winds to drive them to the Sun-Earth second Lagrange point (L2), which is an area of space where the gravitational forces of the Earth and Sun balance one another, allowing a spacecraft to park there. It is at this destination that the modules would join together to form the primary and secondary mirrors, while their sails would be repurposed as a heat shield to protect the growing telescope from sunlight.

The project is still in its infancy, but Savransky will be meeting with NASA at its NIAC Orientation Meeting on June 5 and 6 in Washington DC. The Phase I funding will support the initial definition and analysis of the concept, and if its feasibility is proven, the team hopes to get approval to move onto Phase II, which will open up additional funding.

"That's what the NIAC program is," says Savransky. "You pitch these somewhat crazy-sounding ideas, but then try to back them up with a few initial calculations, and then it's a nine-month project where you're trying to answer feasibility questions."

Source: Cornell University

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