It's mechanically complex so they are proposing automated robotics pulling a foil mesh over cables that are fired out over the crater edges.
But what if they just land a huge inflatable ball inside a crater and it only takes a little gas inside to expand it? It would have to expand 1km but the material could be ultra thin? Hmm maybe not.
PBS Space Time episode on the subject with artist visuals
Well the idea is that it takes far less gas by mass to inflate a balloon against the vacuum of space and support the weight of the envelope in lunar gravity as it does to inflate a balloon against 1 atmosphere and support the envelope in Earth gravity.
It's also worth noting that the pressure vessel need not be spherical either; it only needs to produce the correct shape for the reflective part when pressurized.
For the specific application of the LCRT though it's probably not going to win. For one, a reflector at the HF frequencies they are targeting doesn't even need to be continuous; it can be a large open wire grid and will still be radio opaque at the required frequencies.
https://www.nasa.gov/general/lunar-crater-radio-telescope-lc...
https://www.nasa.gov/solar-system/lunar-crater-radio-telesco...
It's mechanically complex so they are proposing automated robotics pulling a foil mesh over cables that are fired out over the crater edges.
But what if they just land a huge inflatable ball inside a crater and it only takes a little gas inside to expand it? It would have to expand 1km but the material could be ultra thin? Hmm maybe not.
PBS Space Time episode on the subject with artist visuals
https://www.pbs.org/video/what-new-science-would-we-discover...
https://www.youtube.com/watch?v=9F3WRMlZEy4