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Optics put a lot of design constrains on telescopes that mean they'll always be large items, when you're trying to look really far away at really dim objects yo
by rtkwe 7y ago
Optics put a lot of design constrains on telescopes that mean they'll always be large items, when you're trying to look really far away at really dim objects you just need a lot of surface area to collect as much light as possible and the size of the object you can resolve is directly linked to the size of the aperture of the telescope you're using.
Synthetic apertures using interferometry may solve that eventually but we're not there yet it looks like for really high resolution images.
- Robotbeat 7y agoRight, I meant cost in terms of cost per unit dry mass, not just miniaturizing existing satellites. Starlink satellites are really cheap per unit dry mass, not just per satellite. Starship will be super cheap per unit dry mass, enabling ever-larger space telescopes. NASA even tweeted out one concept out for an aperture much larger than JWST using SpaceX's Starship: https://twitter.com/nasagoddard/status/1116310431969239040?lang=en https://twitter.com/nasagoddard/status/1116310431969239040?l...
- rtkwe 7y agoThey might get cheap to launch but they'll be quite expensive to build for the foreseeable future.
- Robotbeat 7y agoI don't see why they need to be. SpaceX has been able to reduce the cost of building space hardware with Starlink by an order of magnitude. When things are cheaper to launch, you can find ways to reduce the cost to build those things.
- rtkwe 7y agoThey're large and complex and the optics for each are generally pretty custom to the application they're being built for. Starlink benefits from decades of work in cubesats and radio transmitters to make most of it's components COTS or nearly COTS. There's not really a lot of earth based applications for gold coated beryllium hexagons to make making a JWST style mirror cheap and easy.
- Robotbeat 7y agoThat's inconsistent with the fact that ground-based astronomy is able to build large and complex optics pretty cheaply, which is the basis for this complaint to begin with. By leveraging these things, you could build an inexpensive space telescope. No one has done so because it has only recently become fairly cheap to launch stuff. JWST is such a terrible example of a space telescope done with good cost constraints, BTW. And that kind of infrared astronomy which needs gold-coated mirrors and 20 Kelvin operating temperatures can't be done on the ground at all. We were discussing near-visible optical instruments and comparing to ground astronomy.