NASA is planning to send a cutting-edge 8.4 foot telescope into the stratosphere carried by a helium-filled balloon the size of a football stadium.

Expected to launch in December 2023 from Antarctica, the telescope, dubbed ASTHROS (short for Astrophysics Stratospheric Telescope for High Spectral Resolution Observations at Submillimetre-wavelengths), will spend about three weeks drifting on air currents roughly four times higher than commercial airliners fly, observing wavelengths of light that are invisible to the human eye, NASA said.

ASTHROS will carry an instrument to measure the motion and speed of gas around newly formed stars to understand how different types of planets form in young solar systems.

When fully inflated with helium, the balloon will be about 400 feet (150 meters) wide, or about the size of a football stadium. A gondola beneath the balloon will carry the instrument and the lightweight telescope.

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Source: NASA’s Goddard Space Flight Center Conceptual Image Lab/Michael Lentz

This illustration shows a high-altitude balloon ascending into the upper atmosphere. When fully inflated, these balloons are 400 feet (150 meters) wide, or about the size of a football stadium, and reach an altitude of 130,000 feet (24.6 miles or 40 kilometers).

“Balloon missions like ASTHROS are higher-risk than space missions but yield high-rewards at modest cost,” said NASA Jet Propulsion Laboratory (JPL) Engineer Jose Siles, 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.”

Because far-infrared instruments need to be kept very cold, many missions carry liquid helium to cool them.

ASTHROS will instead rely on a cryocooler which uses electricity, supplied by ASTHROS’ solar panels, to keep the superconducting detectors close to -451.3 degrees Fahrenheit (-268.5 degrees Celsius) – a little above absolute zero, the coldest temperature matter can reach, NASA explained.

The cryocooler weighs much less than the large liquid helium container that ASTHROS would need to keep its instrument cold for the entire mission.

This means the payload is considerably lighter and the mission’s lifetime is no longer limited by how much liquid helium is on board.

The team expects the balloon will complete two or three loops around the South Pole in about 21 to 28 days, carried by prevailing stratospheric winds.