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If you want to take a radar measurement for something once every 28 days, its great - except for the whole needing to be on the Moon part. Even if you were to b

If you want to take a radar measurement for something once every 28 days, its great - except for the whole needing to be on the Moon part. Even if you were to build a network of radio telescopes on the dark side of the Moon, you'd still have an unavoidable revisit period - and building on the Earth facing side to overcome that defeats the purpose of putting radio telescopes on the Moon. The possibilities for optical telescopes are pretty interesting though.

ncmncm 5y ago
You don't need to be there yourself. And, you can build a dozen of them, half-way around the far side, and get a lot more opportunities to point at anything. Build two close together, and range things hours away.
- sennight 5y ago
  > You don't need to be there yourself. lol, dunno if you are aware or not - but the Arecibo telescope catastrophically collapsed on itself. Serviceability is the concern. The maintenance logs are long for scientific instruments, there is no such thing as a 'set it and forget it' telescope.
  - ncmncm 5y ago
    Hubble has been visited I think twice in 3 decades.
    - sennight 5y ago
      That is an interesting choice for a counter example, because when I think of Hubble I think of failed gyroscopes. Hubble has required 5 servicing missions and always seems to be at risk of moving from a state of crippled-but-still-useful to flat-out-busted-forever. Look at the program's weekly observation logs, keep an eye on the file size - the interesting ones are smaller than average. Gyros and safemode. If you suddenly feel the urge to blurt out "Bbut funding and politics!", then consider my point proven - a Moon based telescope would be far more vulnerable to such externalities. https://www.stsci.edu/ftp/observing/weekly_timeline/ https://www.stsci.edu/ftp/observing/weekly_timeline/
      - ncmncm 5y ago
        A telescope on the moon will not need any gyroscopes. The first Hubble visit was to fix a manufacturing/testing flaw impossible in a radio telescope. Arecibo's failure would also be impossible, as there is no oxidation and no weather on the moon. The only likely failure mode would be from metal fatigue as a consequence of temperature swings, but they are 100% predictable. Maybe you are not aware of the very large difference between an optical telescope and a radio telescope? Optical telescopes always have many precision moving parts. Radio telescopes often have none at all. Anyway, in ten years, given promised SpaceX Starship progress, a visit will be much cheaper than a single Shuttle visit to ISS. Probably such progress will end up turning on thousands of heat-shield tiles not each needing a diaper change after each flight, as the current design seems to require.

ncmncm 5y ago

You don't need to be there yourself. And, you can build a dozen of them, half-way around the far side, and get a lot more opportunities to point at anything. Build two close together, and range things hours away.

sennight 5y ago
> You don't need to be there yourself. lol, dunno if you are aware or not - but the Arecibo telescope catastrophically collapsed on itself. Serviceability is the concern. The maintenance logs are long for scientific instruments, there is no such thing as a 'set it and forget it' telescope.
- ncmncm 5y ago
  Hubble has been visited I think twice in 3 decades.
  - sennight 5y ago
    That is an interesting choice for a counter example, because when I think of Hubble I think of failed gyroscopes. Hubble has required 5 servicing missions and always seems to be at risk of moving from a state of crippled-but-still-useful to flat-out-busted-forever. Look at the program's weekly observation logs, keep an eye on the file size - the interesting ones are smaller than average. Gyros and safemode. If you suddenly feel the urge to blurt out "Bbut funding and politics!", then consider my point proven - a Moon based telescope would be far more vulnerable to such externalities. https://www.stsci.edu/ftp/observing/weekly_timeline/ https://www.stsci.edu/ftp/observing/weekly_timeline/
    - ncmncm 5y ago
      A telescope on the moon will not need any gyroscopes. The first Hubble visit was to fix a manufacturing/testing flaw impossible in a radio telescope. Arecibo's failure would also be impossible, as there is no oxidation and no weather on the moon. The only likely failure mode would be from metal fatigue as a consequence of temperature swings, but they are 100% predictable. Maybe you are not aware of the very large difference between an optical telescope and a radio telescope? Optical telescopes always have many precision moving parts. Radio telescopes often have none at all. Anyway, in ten years, given promised SpaceX Starship progress, a visit will be much cheaper than a single Shuttle visit to ISS. Probably such progress will end up turning on thousands of heat-shield tiles not each needing a diaper change after each flight, as the current design seems to require.