Balloons may seem like an outdated mode of transportation, but for high-flying scientific instruments they’re making a comeback. NASA has unveiled ASTHROS, a new infrared telescope that will be carried to the edge of space by a balloon the size of a football stadium.
ASTHROS, short for Astrophysics Stratospheric Telescope for High Spectral Resolution Observations at Submillimeter-wavelengths, will view the cosmos in far-infrared light. These wavelengths are blocked by Earth’s atmosphere, so infrared observatories are usually space-based, such as Spitzer, Herschel, and the Infrared Space Observatory.
ASTHROS, on the other hand, will be hitched to a high-altitude balloon, which will carry it to a height of 130,000 ft (40,000 m). That’s about four times higher than commercial airliners fly – although it’s still less than halfway to the edge of space.
When fully inflated, the balloon will be about 400 ft (150 m) wide, which makes it about the size of a football stadium. Attached to this will be the ASTHROS instrument, including an 8.4-ft (2.5 m) antenna dish, as well as the mirrors, lenses and cooling systems that will let the telescope observe in far-infrared.
The balloon will be launched from Antarctica, and the stratospheric winds will carry it in two or three loops around the south pole, in a flight that will last between 21 and 28 days. When the work is done, the instrument will separate from the balloon and a parachute will carry it safely to the ground. After that, the telescope can be refurbished for reuse.
ASTHROS will specialize in making 3D maps of the density, speed and motion of gas in regions where newly-forged stars are churning the clouds of debris they were born in. The telescope will focus on four targets: the galaxy Messier 83, a young star called TW Hydrae where planets may be coagulating, and two star-forming regions in the Milky Way.
The team says that ASTHROS will be able to achieve what orbital telescopes can, at a fraction of the cost.
“Balloon missions like ASTHROS are higher-risk than space missions but yield high-rewards at modest cost,” says Jose Siles, a project manager for ASTHROS. “With ASTHROS, we’re aiming to do astrophysics observations that have never been attempted before. The mission will pave the way for future space missions by testing new technologies and providing training for the next generation of engineers and scientists.”
The design of the instrument is now complete, and this month JPL engineers will begin testing the subsystems. If all goes to plan, ASTHROS is pencilled in for launch in December 2023.
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