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The Hubble has a launch mass of 10000kg and has a mirror with a 2.4m diameter and 4.525 m^2 collecting area. The ELT has a diameter of 39.3m area of 978 m^2, th

The Hubble has a launch mass of 10000kg and has a mirror with a 2.4m diameter and 4.525 m^2 collecting area. The ELT has a diameter of 39.3m area of 978 m^2, that is 216 Hubbles. The target cost of getting stuff to LEO using Starship/SuperHeavy is $2m per 100000kg, or $200k per Hubble. It would only cost $43 million to launch the light-gathering equivalent to the ELT. Now, $20/kg to LEO is very optimistic, but even at 5-10x that rate, a more believable $100-200/kg, that would still make the launch possible for 200-400m, which is roughly the cost of a Delta Heavy launch. Scaling this up, a 100m telescope (The OWL) would be 1,735.69 Hubbles and cost $350m to launch at the optimistic price, but still less than $3.5B at the believable price. Basically, if Starship is successful it could have a dramatic effect on astronomy. 216 Hubbles may sound a bit insane, but mass producing them would drive the cost for each down considerably. Without the atmosphere, you don't need the fancy laser-actuator correction mechanism, and you certainly don't need to fight local activists for one of very few locations worldwide where you can plausibly put these things (AFAIK, there are only 3 such locations worldwide - Canary Islands, Cerro Amazones and Hawaii). Not only that, but if you had a constellation of Hubbles, they could be spread out and use interferometry to construct a telescope larger than the Earth (this is the technique that Event Horizon Telescope used). So the question is, is it possible to design a standardized, flatpack hubble-sized mirror+cam sattelite and pull it off for the price of a regular telescope? At ~1.2Eur for the ELT, that would imply $45m per "hubble". Seems doable.

__tg__ 7y ago
Not sure about the Starship numbers but if its is $2m per Hubble mass, then launching 200 hubbles would be $800m, not $43m. This however is not about sending bricks into orbit. The ELT mirrors are segmented and need precise alignment with each other to micron precision. Deploying a segmented mirror in orbit has still not been done (the James Webb Telescope launches in 2021); the engineering involved adds orders of magnitudes of complexity over a single-piece primary mirror such as Hubble has. Add to this maintenance costs: a mirror the size of ELT in orbit needs a huge maintenance program behind it to work at all. The lifetime cost for such a mirror would be in tens of billions, if not hundreds. This is why such large telescopes keep getting built on Earth.
- Gravityloss 7y ago
  Yeah. The money in the space business was never in launchers but in satellites.
  - rbanffy 7y ago
    Satellites need to be incredibly well built because they are ridiculously expensive to deliver. If we can deliver them for a fraction of the cost, it no longer makes sense to build them so expensively.
    - s1artibartfast 7y ago
      I'm not sure that holds true, at least for the big telescopes. The lifetime cost of the hubble is about 10 Billion and the development cost of the James webb telescope is approaching 10 Billion. James Webb will launch on an Ariane 5 rocket, which costs about 140 million per launch. This is about 1-2% of the development costs.
    - Gravityloss 7y ago
      True! The way microcomputers supplanted mainframes. If you launch cheaper satellites more often: - you get to iterate so you can make improvements at a much faster pace - there is less problems from a single failure - more scale effects You can enter a virtuous cycle. There are limits! It can be that it's hard to make a useful satellite once you go below some certain size. And reliability suffers if you try to skimp on good practices. On many scientific satellites, the instruments are one off anyway and are complex, hard and hand built with astronomical costs, so it might not save so much even if the launch and the bus were a lot cheaper.
      - rbanffy 7y ago
        I understand the analogy, but this one is bad. Microcomputers came about because, at some point, we could make small computers with just enough processing power that they could be useful. Mainframes didn't really go anywhere - they are still doing heavy lifting in large corporations, and modern mainframes employ every trick we use to make x86's fast and then a couple that would make x86's prohibitively expensive.
astro123 7y ago
While yes, better launch capability == cheaper to put telescopes in orbit == good for astronomy, its not that simple. Interferometry is HARD. The Keck telescopes which sit 100m apart on the surface of the earth were designed to be used as an interferometer and never lived up to the expectations. The interferometry abilities were shut down about a decade ago. Here's an article which includes a quote from one of the people who designed it who talks about spending 100s of nights trying to get this to work [1]. This only works because these telescopes are physically connected (see the discussion of the VLT in [2]). You are cavalierly talking about getting this working with 1000s of telescopes in space. If you are wondering how we got the event horizon interferometer if it is as hard as I am claiming, things become much easier at long wavelengths [2]. That's why we have lots of radio (ALMA, SKA) interferometers and almost no optical. > At ~1.2Eur for the ELT, that would imply $45m per "hubble". One of these is on a mountain, the other is in space. One you can plug into the mains, the other you need batteries and solar panels etc. One you know how it is oriented (its on the earth) the other you need gyroscopes and control systems and etc. One you can plug an ethernet cable into to get the data, the other you need some sort of transmitting receiving system. One I can go fix with a spanner if something goes wrong, the other costs another X if it does. > Seems doable If you ignore all the complexity of being in space, all the complexity of working with an array of telescopes, the fact that interferometry is way harder in optical, yeah it sounds great! [1] https://skyandtelescope.org/astronomy-news/closure-looms-for-keck-interferometer/ https://skyandtelescope.org/astronomy-news/closure-looms-for... [2] https://www.eso.org/public/usa/teles-instr/technology/interferometry/ https://www.eso.org/public/usa/teles-instr/technology/interf...
- martythemaniak 7y ago
  Well, you kinda have to weigh hard things against each other. A while back there was discussion here about the anti Thirty Meter Telescope protests in Hawaii and someone who lives on the big island gave a really good overview. It pretty much convinced me that that telescope will simply not be built there, period. I could not find the thread, sorry. Apart from that SpaceX is building comms satellites that can handle gigabit speeds at costs around several hundred thousand dollars per satellite or at most the low-millions. Solar and batteries are far ahead from where they were when the Hubble was first built. As I mentioned in another comment, the real reason is because Starship and Starlink are still not quite real. These telescope projects take a long time to design, fund, build, etc, so realistically they can only happen once those two have proven themselves, which will hopefully happen this decade.
dmix 7y ago
The OWL = Overwhelmingly Large Telescope for anyone curious about the reference: https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope
- rbanffy 7y ago
  I'll wait for the LLT, the Ludicrously Large Telescope.
rbanffy 7y ago
If, instead of a Starship you supplement the Superheavy with an expendable second stage, you can get a huge amount of stuff to LEO. And keep the upper stage engines and tanks for attachment to a deep space vehicle that doesn't need to fight gravity wells.
rbanffy 7y ago
A Starship/Superheavy has a diameter of 9m. This fits a mirror about 14 times the area of the Hubble. For a single launch, that's quite remarkable.
- Veedrac 7y ago
  Elon wants an 18m successor once the 9m one works.
dylan604 7y ago
Lots of astronomers would rather not do another space based optical telescope. With Adaptive Optics and the larger ground based mirrors, they are achieving Hubble like if not better than Hubble images. https://www.popularmechanics.com/space/a22240382/neptune-ground-telescope-sharper-images-hubble-adaptive-optics/ https://www.popularmechanics.com/space/a22240382/neptune-gro...
gok 7y ago
Mass probably doesn't scale linearly with mirror area. Moreover it's increasingly unclear how much space-based astrophotography matter given recent advances in adaptive optics.
abacadaba 7y ago
Wasn't hubble basically just a repurposed spy satellite? We made lots of those.
rkagerer 7y ago
and you certainly don't need to fight local activists But ironically, you may begin to get grief from astronomers if you really start to scale (see, Starlink).

__tg__ 7y ago

Not sure about the Starship numbers but if its is $2m per Hubble mass, then launching 200 hubbles would be $800m, not $43m. This however is not about sending bricks into orbit. The ELT mirrors are segmented and need precise alignment with each other to micron precision. Deploying a segmented mirror in orbit has still not been done (the James Webb Telescope launches in 2021); the engineering involved adds orders of magnitudes of complexity over a single-piece primary mirror such as Hubble has. Add to this maintenance costs: a mirror the size of ELT in orbit needs a huge maintenance program behind it to work at all. The lifetime cost for such a mirror would be in tens of billions, if not hundreds. This is why such large telescopes keep getting built on Earth.

Gravityloss 7y ago
Yeah. The money in the space business was never in launchers but in satellites.
- rbanffy 7y ago
  Satellites need to be incredibly well built because they are ridiculously expensive to deliver. If we can deliver them for a fraction of the cost, it no longer makes sense to build them so expensively.
  - s1artibartfast 7y ago
    I'm not sure that holds true, at least for the big telescopes. The lifetime cost of the hubble is about 10 Billion and the development cost of the James webb telescope is approaching 10 Billion. James Webb will launch on an Ariane 5 rocket, which costs about 140 million per launch. This is about 1-2% of the development costs.
  - Gravityloss 7y ago
    True! The way microcomputers supplanted mainframes. If you launch cheaper satellites more often: - you get to iterate so you can make improvements at a much faster pace - there is less problems from a single failure - more scale effects You can enter a virtuous cycle. There are limits! It can be that it's hard to make a useful satellite once you go below some certain size. And reliability suffers if you try to skimp on good practices. On many scientific satellites, the instruments are one off anyway and are complex, hard and hand built with astronomical costs, so it might not save so much even if the launch and the bus were a lot cheaper.
    - rbanffy 7y ago
      I understand the analogy, but this one is bad. Microcomputers came about because, at some point, we could make small computers with just enough processing power that they could be useful. Mainframes didn't really go anywhere - they are still doing heavy lifting in large corporations, and modern mainframes employ every trick we use to make x86's fast and then a couple that would make x86's prohibitively expensive.

astro123 7y ago

While yes, better launch capability == cheaper to put telescopes in orbit == good for astronomy, its not that simple. Interferometry is HARD. The Keck telescopes which sit 100m apart on the surface of the earth were designed to be used as an interferometer and never lived up to the expectations. The interferometry abilities were shut down about a decade ago. Here's an article which includes a quote from one of the people who designed it who talks about spending 100s of nights trying to get this to work [1]. This only works because these telescopes are physically connected (see the discussion of the VLT in [2]). You are cavalierly talking about getting this working with 1000s of telescopes in space. If you are wondering how we got the event horizon interferometer if it is as hard as I am claiming, things become much easier at long wavelengths [2]. That's why we have lots of radio (ALMA, SKA) interferometers and almost no optical. > At ~1.2Eur for the ELT, that would imply $45m per "hubble". One of these is on a mountain, the other is in space. One you can plug into the mains, the other you need batteries and solar panels etc. One you know how it is oriented (its on the earth) the other you need gyroscopes and control systems and etc. One you can plug an ethernet cable into to get the data, the other you need some sort of transmitting receiving system. One I can go fix with a spanner if something goes wrong, the other costs another X if it does. > Seems doable If you ignore all the complexity of being in space, all the complexity of working with an array of telescopes, the fact that interferometry is way harder in optical, yeah it sounds great! [1] https://skyandtelescope.org/astronomy-news/closure-looms-for-keck-interferometer/ https://skyandtelescope.org/astronomy-news/closure-looms-for... [2] https://www.eso.org/public/usa/teles-instr/technology/interferometry/ https://www.eso.org/public/usa/teles-instr/technology/interf...

martythemaniak 7y ago
Well, you kinda have to weigh hard things against each other. A while back there was discussion here about the anti Thirty Meter Telescope protests in Hawaii and someone who lives on the big island gave a really good overview. It pretty much convinced me that that telescope will simply not be built there, period. I could not find the thread, sorry. Apart from that SpaceX is building comms satellites that can handle gigabit speeds at costs around several hundred thousand dollars per satellite or at most the low-millions. Solar and batteries are far ahead from where they were when the Hubble was first built. As I mentioned in another comment, the real reason is because Starship and Starlink are still not quite real. These telescope projects take a long time to design, fund, build, etc, so realistically they can only happen once those two have proven themselves, which will hopefully happen this decade.

dmix 7y ago

The OWL = Overwhelmingly Large Telescope for anyone curious about the reference: https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope

rbanffy 7y ago
I'll wait for the LLT, the Ludicrously Large Telescope.

rbanffy 7y ago

If, instead of a Starship you supplement the Superheavy with an expendable second stage, you can get a huge amount of stuff to LEO. And keep the upper stage engines and tanks for attachment to a deep space vehicle that doesn't need to fight gravity wells.

rbanffy 7y ago

A Starship/Superheavy has a diameter of 9m. This fits a mirror about 14 times the area of the Hubble. For a single launch, that's quite remarkable.

Veedrac 7y ago
Elon wants an 18m successor once the 9m one works.

dylan604 7y ago

Lots of astronomers would rather not do another space based optical telescope. With Adaptive Optics and the larger ground based mirrors, they are achieving Hubble like if not better than Hubble images. https://www.popularmechanics.com/space/a22240382/neptune-ground-telescope-sharper-images-hubble-adaptive-optics/ https://www.popularmechanics.com/space/a22240382/neptune-gro...

gok 7y ago

Mass probably doesn't scale linearly with mirror area. Moreover it's increasingly unclear how much space-based astrophotography matter given recent advances in adaptive optics.

abacadaba 7y ago

Wasn't hubble basically just a repurposed spy satellite? We made lots of those.

rkagerer 7y ago

and you certainly don't need to fight local activists But ironically, you may begin to get grief from astronomers if you really start to scale (see, Starlink).