Can telescopes in space replace ground based telescopes?

[joek]

Mostly every major innovative project in spaceflight (and outside of it, to be honest) should have been cancelled by that metric.

What "metric" are you referring to? Plenty of programs ("innovative" and otherwise) have been cancelled.

Not trying to redeem the incompetence and dishonesty that I agree was avoidable, but it was hardly a one-off...

But you are.

JWST was a mismanaged disaster by any measure. Let's all hope it was a "one-off". Excusing it is imply accepting the normalization of deviance.

[eeergo]

Mostly every major innovative project in spaceflight (and outside of it, to be honest) should have been cancelled by that metric.

What "metric" are you referring to? Plenty of programs ("innovative" and otherwise) have been cancelled.

Not trying to redeem the incompetence and dishonesty that I agree was avoidable, but it was hardly a one-off...

But you are.

JWST was a mismanaged disaster by any measure. Let's all hope it was a "one-off". Excusing it is imply accepting the normalization of deviance.

You're engaging in both a false equivalence and a non-sequitur at the same time, while skirting ad-hominems with your tone, and explicitly deleting the on-topic point in my post. Congrats.

False equivalence: Cancellations having existed (or projects respecting budgets) does not imply there are plenty of important-to-egregious overruns whose continuation vs cancellation was justified a posteriori, just like JWST has been doing since launch. The most glaring example is ISS, without which the commercialization of LEO would most likely not have happened, international cooperation would have been stymied even further, and earlier, than current affairs have taken it, HSF would most likely have suffered a decade-long, if not more, gap in flights, etc. It was close to cancellation both during construction on the ground, on-orbit assembly and the early utilization phase.

Likewise, most HSF projects were close to cancellation at some point in their tenure, with rabid proponents of such measures: from Apollo (before and just after Apollo XI, and finally dramatically after Apollo XVII) to STS (throughout its lifetime) to SLS.

Beyond HSF, Hubble was as close to cancellation as JWST, including after its on-orbit incident after launch, and throughout its life due to (IMHO) shortsighted beancounting regarding STS servicing missions.

Most "Flagship" missions in NASA, ESA and other agencies had similar trajectories. WFIRST/Nancy-Roman has had to deal with such talk since the NRO mirros were unveiled, even though its cost increase has -for now, crossing fingers- been modest. Ditto for MSR. Cassini was under the sword of Damocles several times, as was MSL/Curiosity, GLAST, Suomi/NPOESS-PP, Glory, Europa Clipper is still feeling the breeze left over by its latest swoop... Internationally, ExoMars, Athena, Cluster, SOHO...

Outside of spaceflight, many transportation (both vehicles and civil engineering) and scientific projects suffer similar trends. A notable project that WAS cancelled and led to very bad outcomes for the community and related neighboring fields, far exceeding the cost savings, was the infamous SSC accelerator.

Most of these have in common that they were doing something unprecedented, as opposed to valuable yet more technically run-of-the-mill missions like the mentioned Kepler. The MERs were a virtuous exception in this field.

Non-sequitur: I explicitly said JWST's mismanagement is not redeemable, and that it was avoidable. No, the philosophy shouldn't be "it costs what it costs" barring specific, very well justified exceptions. Yet without much discussion to back it, you just call my qualifiers (nothing is black or white, especially in light of the above) "excuses", ignore the challenges associated with extremely innovative projects that push the state of the art forward, and mix in the ominous "normalization of deviance" in a context far from where it was coined.

[joek]

...

Said what I had to say about JWST long ago in other threads. Plenty of "backstory" if you've read those threads and the references. Simply put, JWST was a disaster. Let's not try and sugar coat it.

[JulesVerneATV]

Astro Brief: Lunar Radio Telescope
https://www.ksmu.org/show/astro-brief/2025-08-21/astro-brief-lunar-radio-telescope

[floss]

Build a 2 km optical telescope beside the radio telecom and we will be able to see the planet's around other stars .

[JulesVerneATV]

NASA's Hubble Space Telescope and Chandra X-ray Observatory joined forces to find an elusive intermediate mass black holes
https://www.yahoo.com/news/videos/hubble-spots-nearly-impossible-intermediate-190000812.html

A tiny detector could unveil gravitational waves we’ve never seen before
https://www.sciencedaily.com/releases/2025/10/251003033920.htm

DECi-hertz Interferometer Gravitational wave Observatory (or DECIGO) similar to cancelled LISA, is a proposed Japanese space-based gravitational wave observatory, LISA is supported by the ESA and expected to have a Launch date 2035,  .
https://web.archive.org/web/20230201204235/https://dcc.ligo.org/public/0038/G060318/000/G060318-00.pdf
Japan design is similar to LISA, with four zero-drag satellite clusters (two colocated) in a triangular arrangement, but using a smaller separation of only 1000 km

Hubble Space Telescope watches dying star chow down on a Pluto-like world filled with ice
https://www.space.com/astronomy/hubble-space-telescope/hubble-space-telescope-watches-dying-star-chow-down-on-a-pluto-like-world-filled-with-ice


Some estimate Starship can be ~$90 million but maybe as high as 200 million until costs drop

another US Private company New Glenn might also be there offering cheap payloads or a commercial company from China or India, the Russians are currently under sanctions after the Ukraine invasion. Titan IV was retired in 2005, ESA Ariane is falling behind with others going reusable, Germany and PLD Space are trying commercial.  Shuttle payload to LEO was approximately $54,500 per kg, The Shuttle derived SLS is another system for large payloads but perhaps too expensive. Since Elon Musk'sspace missions launching objects into low-Earth orbit has come down by "a factor of 20."

Musk's Space-X is on the 11th flight but still no payload to orbit

SpaceX completes 11th test flight of its Starship rocket
https://www.nbcnews.com/science/space/spacex-completes-starship-rocket-test-flight-rcna237463

[Hobbes-22]

DECi-hertz Interferometer Gravitational wave Observatory (or DECIGO) similar to cancelled LISA, is a proposed Japanese space-based gravitational wave observatory, LISA is supported by the ESA and expected to have a Launch date 2035,  .

Cancelled? Are you sure you intended to write that?

[JulesVerneATV]

Cancelled?

Sorry badly worded,  the various ideas for Gravity Wave observatories are on Earth and in outer space are complementary rather than competitive. LISA is alive and it has not been the only one to see troubles and cuts over the years https://web.archive.org/web/20110604121537/http://www.astrobio.net/exclusive/4005/rage-against-the-dying-of-the-light 2011 news on SIM and TPF

They discussed a joint mission between ESA and NASA in 1997, then NASA withdrew, 2008, 2009 cuts, back in for more science more cuts in 2016 then NASA joins again and usually missions that require "recovery actions" end up adding a lot to the overall budget and now more rumors of 'threats' but all is ok.

June, 2025 news

'European Space Agency reveals 3 key space missions threatened by Trump's NASA budget cuts'
https://www.space.com/space-exploration/european-space-agency-reveals-3-key-european-space-missions-threatened-by-trumps-nasa-budget-cuts

Venus orbiter EnVision also mentioned and largest X-ray observatory ever planned, 'NewAthena' so not just talk about 'LISA'

Lisa-pathfinder mission has already flown and that cost was 490 million 'Euros'
https://www.space.com/33094-lisa-pathfinder-gravitational-wave-tech-demonstration-results.html
the mission ended in 2017

2035 LISA launch date remained unchanged.
https://www.esa.int/Science_Exploration/Space_Science/LISA/Construction_of_ESA_s_ambitious_LISA_mission_begins

[ralfvandebergh]

Frankly, personally I don't like the premise of this reasoning. This is, of course, from an industrial perspective, a businessman's reasoning, which is understandable. No hate here. A better question would be: Is it worth filling the sky with satellites only for improved internet communication? Astrophotographers already have to use tricks to remove the many satellite trails from their photos just to take a nice picture, let alone professional astronomers with their scientific work. And with all the competing companies, this is just the beginning. Of course, you could argue that these are also celestial objects and belong there. But that's not the point here. Don't get me wrong, I'm even a satellite photographer; I just photograph almost exclusively satellites.

Then there's the telescope industry and the people who work on the ground in observatories, operators and (maintenance) technicians for instance. They'll lose their jobs too, right?

And to go slightly off-topic, I haven't even mentioned the environmental impact of all these launches, not to mention the subsequent atmospheric burn-ups of so many satellites. And what about the increased collision risks? Look, we have to take some responsibility, we can't just keep launching and assume all this has no impact on our environment. That's like a child in a toy store. I'm a rocket enthusiast too, but we also have to be willing to take responsibility. Of course, launches will always continue to increase in the era we live in, and I think that's great, but let's work hard on more environmentally friendly emissions and other solutions.

Mars really should be a backup location; we shouldn't go there because it has become uninhabitable on Earth.

Ralf Vandebergh

"Astronomers should be happy about SpaceX. Cheap access to space will enable a lot of space telescopes, no worries about mega constellations disturbing ground based astronomy"


This is one of the most common answers one can read when talking about effects of starlink and other satellite constellations on ground based telescopes. Even from people like Everday Astronaut or Elon Musk himself. My feeling is that this is not a very realistic argument but I want to learn more about it and hear some thoughtfull opinions on this topic?

Let's say Starship will be flying soon and it will actually be very very cheap. Can you really replace ground based telescopes? What types of research/wavelengths could be done in space? And what types of research need to be done on the ground and why?

[ralfvandebergh]

Comet picture with Starlink trails example:

https://www.reddit.com/r/astrophotography/comments/1oskm10/comet_lemon_and_satellites/

Frankly, I don't like the premise of this reasoning. This is, of course, from an industrial perspective, a businessman's reasoning, which is understandable. No hate here. A better question would be: Is it worth filling the sky with satellites for improved internet communication? Astrophotographers already have to use tricks to remove the many satellite trails from their photos just to take a nice picture, let alone professional astronomers with their scientific work. And with all the competing companies, this is just the beginning. Of course, you could argue that these are also celestial objects and belong there. But that's not the point here. Don't get me wrong, I'm even a satellite photographer; I just photograph almost exclusively satellites.

Then there's the telescope industry and the people who work on the ground in observatories. They'll lose their jobs too, right?

And I haven't even mentioned the environmental impact of all these launches, not to mention the subsequent atmospheric burn-ups of so many satellites. Look, we have to take some responsibility, we can't just keep launching and assume all this has no impact on our environment. That's like a child in a toy store. I'm a rocket enthusiast too, but we also have to be willing to take responsibility. Of course, launches will always continue to increase in the era we live in, and I think that's great, but let's work hard on more environmentally friendly emissions and other solutions.

Mars really should be a backup location; we shouldn't go there because it has become uninhabitable on Earth.

Ralf Vandebergh

"Astronomers should be happy about SpaceX. Cheap access to space will enable a lot of space telescopes, no worries about mega constellations disturbing ground based astronomy"


This is one of the most common answers one can read when talking about effects of starlink and other satellite constellations on ground based telescopes. Even from people like Everday Astronaut or Elon Musk himself. My feeling is that this is not a very realistic argument but I want to learn more about it and hear some thoughtfull opinions on this topic?

Let's say Starship will be flying soon and it will actually be very very cheap. Can you really replace ground based telescopes? What types of research/wavelengths could be done in space? And what types of research need to be done on the ground and why?