I've just noticed the following items:
- CNET: NASA to send stadium-size balloon skyward to study the cosmos
- JPL/NASA News: NASA Mission Will Study the Cosmos With a Stratospheric Balloon Even in 2020 balloons are used for space exploration; Q.E.D.
- Scitech Daily: NASA ASTHROS: Stratospheric Balloon the Size of a Football Stadium Will Carry a Cutting-Edge Telescope
The last one says:
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 minus 451.3 degrees Fahrenheit (minus 268.5 degrees Celsius) — a little above absolute zero, the coldest temperature matter can reach. The cryocooler weighs much less than the large liquid helium container that ASTHROS would need to keep its instrument cold for the entire mission. That 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. Once the science mission is complete, operators will send flight termination commands that separate the gondola, which is connected to a parachute, from the balloon. The parachute returns the gondola to the ground so that the telescope can be recovered and refurbished to fly again.
Question: The JWST is absurdly late and over budget. Hypothetically, with hindsight, would it have been a better idea to put a JWST-like instrument on a balloon in a similar fashion to ASTHROS? There would have been a huge savings in R&D because every month the system could be serviced, so all the work and time and mass and energy making it space-worthy and ultra-reliable could be saved, and every month the instruments could be swapped out, repaired, improved, etc. rather than the final instrumentation being built once and sent to Sun-Earth L2 forever. Even Hubble benefitted from several swap-outs of equipment.
- The JWST - What happens if/when it breaks? It stays broke!
- Is it possible to refuel the James Webb Space Telescope? No it is not!
- Can the James Webb Space Telescope basically manage its own orbit if necessary? No it can not!