NASA has started to work on a new mission to send a 2.5 meter ( 8.4 foot ) telescope into
the stratosphere on a balloon, the size of a football stadium. The mission ASTHROS or Astrophysics Stratospheric Telescope for High Spectral Resolution Observations at Submillimeter-wavelengths is sheduled to
launch in December 2023 from Antarctica.
The launch place is chosen Antarctica because the equipment in ASTHROS payload is required to stay at low temperature while launching, as instead of liquid hilium ASTHROS
will rely on a cryocooler, which uses electricity ( supplied by ASTHROS' solar panels ) to keep the superconducting detectors close to minus minus ( - ) 268.5 degrees Celsius - a
little above absolute zero ( absolute zero is the coldest temperature matter can reach ).
This illustration shows a high-altitude balloon ascending into the upper atmosphere. Courtesy : NASA's Goddard Space Flight Center Conceptual Image Lab/Michael Lentz
The ASTHROS telescope observes far-infrared light. To do that, ASTHROS will need to reach
an altitude of about 40 kilometers, roughly four times higher than commercial airliners fly; although that is not space, ( Space begins after Karman line at an altitude 100 km
from sea level ) the altitude is enough to observe wavelengths of light that aren't visible from the ground.
Why the balloon is used despite having a high risk ? The answer is it is cheap compared to a rocket
launched mission. "Balloon missions like ASTHROS are higher-risk than space missions but yield high-rewards at modest cost," said 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."
This time-lapse video shows the launch of the Stratospheric Terahertz Observatory II (STO-2), a NASA astrophysics mission, from Antarctica in 2016. Courtesy : NASA/JPL-Caltech
Mission : During flight, ASTHROS will study four main targets. Two of which are
star-forming regions in the Milky Way galaxy. Quoting from official website of NASA JPL, "It will also for the first time detect and map the presence of two specific types of
nitrogen ions ( atoms that have lost some electrons ). These nitrogen ions can reveal places where winds from massive stars and supernova explosions have reshaped the gas
clouds within these star-forming regions.
In a process known as stellar feedback, such violent outbursts can, over millions of years, disperse the surrounding material and impede star formation or halt it altogether.
But stellar feedback can also cause material to clump together, accelerating star formation. Without this process, all the available gas and dust in galaxies like our own would
have coalesced into stars long ago.
ASTHROS will make the first detailed 3D maps of the density, speed, and motion of gas in these regions to see how the newborn giants influence their placental material.
By doing so, the team hopes to gain insight into how stellar feedback works and to provide new information to refine computer simulations of galaxy evolution."
The third target will be observing signs of stellar feedback in the galaxy Messier 83. Finally, the fourth target of ASTHROS will be to observe TW Hydrae, a
young star surrounded by a wide disk of dust and gas where planets may be forming.
Data Sources: https://www.jpl.nasa.gov/news/news.php?feature=7712