The American space agency NASA is working on a mission to bring a 2.5-meter-diameter telescope into the stratosphere with a large helium balloon. The mission is to provide insights into the evolution of galaxies.
Bringing the telescope into the stratosphere allows it to perceive wavelengths that are not visible from the ground because they are blocked by the atmosphere. NASA wants to use the telescope to make observations in the infrared spectrum. The mission focuses on research into the movement and velocity of gas around newly formed stars.
NASA calls the mission Asthros, which stands for astrophysics stratospheric telescope for high spectral resolution observations at submillimeter-wavelengths. The balloon is scheduled to take off in Antarctica in December 2023. The balloon is then expected to float on the air currents for about three to four weeks and capture images of the space. At the end of the mission, the telescope is disconnected and returns to earth with a parachute, allowing reuse.
The team has now completed work on the telescope and infrared light capture instruments. The balloon is fitted with a 2.5 meter diameter telescope, which is approximately the same as the Hubble Space Telescope. In early August, NASA’s Jet Propulsion Lab will begin integrating and testing the systems.
The superconducting detectors for capturing infrared light must be cooled to -268.5ºC. Usually liquid helium is used for this, but Ashtros is equipped with an electric cryocooler and solar panels to generate the necessary power. According to NASA, that solution is much lighter than sending up a stock of liquid helium. It also extends the life of the mission, because it does not depend on the amount of coolant.
NASA chooses a balloon because it is a cheap and quick way to get the telescope up. As a result, more risks can be taken when making hardware choices. For example, the space agency can bring equipment that has never been tested in space before, without huge consequences if it fails.
With the Asthros mission, NASA aims to create detailed 3D maps of the density, velocity, and motion of gas seen around the formation of stars. This should yield new insights that can be used to improve computer simulations of the evolution of galaxies. The mission focuses specifically on four targets, including the Carina Nebula in the Milky Way Galaxy, Messier 83, or the Southern Windmill Galaxy, and TW Hydrae, a young star some 196 light-years away.
NASA’s Scientific Balloon Program has been operating balloon flights at the Wallops Flight Facility in the U.S. state of Virginia for thirty years. Ten to fifteen missions are initiated from there each year, which are carried out at locations worldwide. These are scientific experiments or educational missions.