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Launch costs are only a fraction of the total cost of orbital telescopes, so don't get your hopes up. For reference, the WFIRST telescope came with satellite b

by qayxc 6y ago

Launch costs are only a fraction of the total cost of orbital telescopes, so don't get your hopes up. For reference, the WFIRST telescope came with satellite bus and 2.4m mirror for free yet already has a 3.2 billion dollar price tag attached to it. Even the most expensive launch provider would be less than 10% of that cost. It only weighs about 4 metric tons by the way, so there's that. Just a quick reality check on the unrealistic assumptions some people have.

Gravityloss 6y ago
I wonder, if you know you were launching one every six months for the next 20 years, what would the unit cost be? You might be able to use a commercial satellite bus for example. It would be fine if some would experience failures, as there would be the next one already lined up. Just put different instrument(s) at the end of the optical path in each. As example, Hubble has five instruments. https://hubblesite.org/mission-and-telescope/instruments https://hubblesite.org/mission-and-telescope/instruments One could start a design from something like CHEOPS with a 30 cm mirror. https://sci.esa.int/web/cheops/-/54032-spacecraft https://sci.esa.int/web/cheops/-/54032-spacecraft
- HDMI_Cable 6y ago
  Do we need that many telescopes though? It seems like one only needs many 5 at any given time.
  - Gravityloss 6y ago
    One can already see that the existing terrestrial and space telescopes have long queues for observing time. Maybe more experimental instruments would be nice as well.
  - jjk166 6y ago
    There are currently 35 space-based telescopes in active service with 6 planned to launch in the next 12 months. [0] https://en.wikipedia.org/wiki/List_of_space_telescopes https://en.wikipedia.org/wiki/List_of_space_telescopes
mrfusion 6y ago
But how much of that telescope cost is because of high launch costs. Ie using the lightest materials, overbuilding because maintenance is impossible, etc.
- qayxc 6y ago
  Hard to tell in detail, but not as much. The primary cost factors are instrument development, ground segments, staff (over years, e.g. 5-10 years development plus ~5 years primary mission plus extensions), testing, and building (no economy of scale here). The most counter-intuitive observations is that the cheaper your launch-costs, the higher the portion they represent w.r.t. total mission cost. A "cheap" (e.g. sub-50 million dollar) telescope for example would have launch costs come in at up to 50% of the total cost when launched on a medium-sized launcher or with a second payload. It's a multivariable optimisation problem and the best solution depends on the variables that you want to optimise for.

by qayxc 6y ago

Gravityloss 6y ago

I wonder, if you know you were launching one every six months for the next 20 years, what would the unit cost be? You might be able to use a commercial satellite bus for example. It would be fine if some would experience failures, as there would be the next one already lined up. Just put different instrument(s) at the end of the optical path in each. As example, Hubble has five instruments. https://hubblesite.org/mission-and-telescope/instruments https://hubblesite.org/mission-and-telescope/instruments One could start a design from something like CHEOPS with a 30 cm mirror. https://sci.esa.int/web/cheops/-/54032-spacecraft https://sci.esa.int/web/cheops/-/54032-spacecraft

HDMI_Cable 6y ago
Do we need that many telescopes though? It seems like one only needs many 5 at any given time.
- Gravityloss 6y ago
  One can already see that the existing terrestrial and space telescopes have long queues for observing time. Maybe more experimental instruments would be nice as well.
- jjk166 6y ago
  There are currently 35 space-based telescopes in active service with 6 planned to launch in the next 12 months. [0] https://en.wikipedia.org/wiki/List_of_space_telescopes https://en.wikipedia.org/wiki/List_of_space_telescopes

mrfusion 6y ago

But how much of that telescope cost is because of high launch costs. Ie using the lightest materials, overbuilding because maintenance is impossible, etc.

qayxc 6y ago
Hard to tell in detail, but not as much. The primary cost factors are instrument development, ground segments, staff (over years, e.g. 5-10 years development plus ~5 years primary mission plus extensions), testing, and building (no economy of scale here). The most counter-intuitive observations is that the cheaper your launch-costs, the higher the portion they represent w.r.t. total mission cost. A "cheap" (e.g. sub-50 million dollar) telescope for example would have launch costs come in at up to 50% of the total cost when launched on a medium-sized launcher or with a second payload. It's a multivariable optimisation problem and the best solution depends on the variables that you want to optimise for.