NASA has awarded a $2 million grant to the Jet Propulsion Laboratory, The Aerospace Corp. — and Xplore, a Seattle-based space venture — to develop the design architecture for a far-out telescope array that would use the sun’s gravitational field as a lens to focus on alien planets.
The Phase III award from the NASA Innovative Advanced Concepts program, or NIAC, would cover two years of development work and could lead to the launch of a technology demonstration mission in the 2023-2024 time frame.
Xplore’s team will play a key role in designing the demonstration mission’s spacecraft, which would be launched as a rideshare payload and propelled by a deployable solar sail.
The partners in the Solar Gravity Lens Focus mission settled on solar sails as the best way to get the array’s imaging spacecraft out to the jaw-dropping distance of 547 AU (50 billion miles, or 80 billion kilometers) on a reasonable time scale.
Solar sails on spacecraft are pushed by the pressure of photons from the sun, just as the sails on sailboats are pushed by the wind. The technology was most recently tested on the Planetary Society’s Lightsail 2 experiment (with debatable results).
The demonstration mission is meant to show that the constant push from solar radiation could drive a spacecraft to speeds of about 25 to 40 kilometers per second (15 to 25 miles per second, or 5 to 8 AU per year). That would be two to three times as fast as NASA’s Voyager 1 interstellar probe. Such a probe could zoom past Jupiter in less than a year.
But that’s just the start. If the demonstration mission is successful, NASA would have to decide whether to go ahead with the full Solar Gravity Lens Focus telescope array a decade later. The array would be composed of swarms of small spacecraft, each one with a bigger solar sail that could achieve speeds of more than 100 kilometers per second (more than 62 miles per second, or 20 AU per year). That’s what it would take to get the probes out to their observation point within 25 to 30 years.
From that vantage point, the array of spacecraft would capture light rays that have been focused by the sun’s gravitational field, in accordance with general relativity.
It would take three days for the data sent back by the array to reach Earth. But when those readings are integrated, they could give scientists an incredibly detailed look at planets far beyond our solar system.
The scientists behind the SGLF mission say it should be possible to put together enough pixels to make out the disk of an Earthlike exoplanet from 100 light-years away, at a resolution of 25 kilometers (40 miles) per pixel. That would be “enough to see surface features and signs of habitability,” principal investigator Slava Turyshev, a senior research scientist at JPL, said in NASA’s mission description.
The SGLF concept has already gone through two rounds of development, backed by Phase I and Phase II grants from the NIAC program. NIAC judged the concept promising enough to proceed to Phase III.
“This award brings us toward a proof-of-concept flight that would exit the solar system faster than any previous spacecraft,” Tom Heinsheimer, The Aerospace Corp.’s technical co-lead for the SGLF mission, said in a news release.
Xplore’s design for the demonstration mission’s solar sail draws upon the SunVane concept that was originally developed by L’Garde, another space technology company. Darren Garber, who helped create the concept at L’Garde and provided support for the LightSail project, is a co-founder of Xplore and the company’s chief technology officer.
Lisa Rich, Xplore’s chief operating officer, said Garber’s experience in solar-sail development will come into play for the SGLF technology demonstration mission, and for what comes afterward.
“Xplore is laying the groundwork to revolutionize the transit speed to destinations in our solar system and beyond,” she said today in a news release.
“Once Xplore competes the design, build and first flight of the TDM vehicle, the company would accelerate these missions — perhaps sending one per year, to rapidly advance solar system exploration while providing fact reaction options for flybys of newly discovered interstellar objects like ‘Oumuamua, and high-energy intercepts for planetary defense,” Rich said.
Alan Stern, a planetary scientist at the Southwest Research Institute who serves as principal investigator for NASA’s New Horizons mission to Pluto and the Kuiper Belt, said SGLF would be “an incredible mission with incredible technology.”
“I am incredibly excited to see it selected for study by NIAC,” Stern said. “SGLF offers to revolutionize both exoplanet science and propulsion technology if implemented.”
SGLF isn’t the only project on Xplore’s to-do list. The company is also developing the design for Xcraft probes that could take on missions to the moon and other deep-space destinations starting as soon as next year. Earlier this month, Xplore said it won an Air Force study contract to develop an architecture for keeping track of missions between Earth and the moon.
