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> That needs some citations. The James Webb Telescope's mirror is 6.5m in diameter. It took decades and billions of dollars of overruns and a prayer to launch a
by _dain_ 2y ago
> That needs some citations. The James Webb Telescope's mirror is 6.5m in diameter. It took decades and billions of dollars of overruns and a prayer to launch and work correctly. There is no hope of most hardware repairs.
Because it had to get launched folded up, because the launch vehicles were so space- and mass-constrained. The unfolding mechanism was enormously complicated and added to much of the cost.
Now we can send up bigger, heavier objects for much less money. The 6.5m mirror fits comfortably inside Starship's cargo bay, unfolded. JWST is a one-off clockwork masterpiece; future space telescopes will come off an assembly line. There will be thousands in orbit, pointed at every part of the heavens simultaneously.
- lumost 2y agoBack of the envelope math would suggest that 8-10 JWTs could be launched in a single starship flight making for an impressive telescope array.
- stevage 2y agoDid you factor in the fuel to get to where it needs to be?
- pfdietz 2y agoPropellant is very cheap.
- stevage 2y agoYeah but it is still mass and volume that might reduce available payload?
- TeMPOraL 2y agoDoesn't matter. The point is that, thanks to reusable boosters, launching satellite constellations, and other recent developments, space is becoming much cheaper - so if you can't fit 8 JWSTs in one Starship, just launch the rest on another, and it'll still come out cheaper than the original JWST.
- pfdietz 2y agoUltimately it becomes so cheap we'll be able to put workers up there to assemble and maintain the telescopes, just like on Earth. We might see telescopes in telescope farms near a small station for the workers. It might even be possible to send workers out to the Sun-Earth L2 point to maintain telescopes there.
- KiwiJohnno 2y agoNot really. Starship is aiming for 150 MT to LEO. The launch mass of JSWT was 6.5 MT. Yes, JSWT was launched into a L2 transfer orbit and not LEO, but from the above margins there is probably enough spare capacity for this.
- rickydroll 2y agohttps://en.wikipedia.org/wiki/Extremely_Large_Telescope https://en.wikipedia.org/wiki/Extremely_Large_Telescope The 39-meter primary mirror has 798 1.4-meter segments, each individually adjustable. The scaffolding required to hold all the segments is "significant" and must be assembled in orbit. We would stick this out next to the James Webb at L2, which means we would need the ability to travel to L2 to construct this mythical orbital extremely large telescope. With our current technology, we can build ELT on Earth for a fraction of the cost of putting it in orbit.
- feoren 2y agoWhy would you assemble it at L2 instead of assembling it in LEO and then sending it out on its own?
- rickydroll 2y agoIt is not impossible. But you would have to design the telescope to be a rocketship complete with motors, fuel tanks, and all that other fun stuff. That would significantly increase the telescope's complexity to withstand the force and vibration of a rocket engine. Theoretically, one could use ion drives, but the engineering challenges of creating ion drives capable of moving a few hundred tons of telescope are significant. It is much simpler to build the telescope equivalent of IKEA flatpack furniture and assemble it on-site than it is to build it and then move it.
- Asraelite 2y ago> the engineering challenges of creating ion drives capable of moving a few hundred tons of telescope are significant. Why? Just take existing ion engine designs but use a lot of them.
- _dain_ 2y agoFor one thing, before this decade is out we will have the lift capacity to get an ELT-worth of mass to L2. And the lack of need to correct for atmospheric distortion would simplify the design considerably. But it's beside the point. Such a singular mega-telescope would no longer be the only way to do astronomy in space. A world of radically lower launch costs gives more possibilities. We could have a fleet of thousands of independent small/medium sized space telescopes. That way, we wouldn't have to carefully ration imaging time between competing astronomy projects anymore. High quality data would become cheap and abundant, procured on-demand.
- bmitc 2y ago> future space telescopes will come off an assembly line. There will be thousands in orbit, pointed at every part of the heavens simultaneously. Like I said: citations. > Now we can send up bigger, heavier objects for much less money. This hasn't even been demonstrated.
- _dain_ 2y agomate I can't give you a citation for something that hasn't happened yet. it's a reasonable extrapolation of current trends. don't give me this "citation needed" whining.