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Comment by tgsovlerkhgsel | Hacker News Reader

Hubble weighs 11 tons, well within the capacity to LEO of a single $70M reusable Falcon 9 launch (probably around half that cost for SpaceX).

I wonder how expensive a telescope like this would be today, both the design and actual manufacturing, and whether it would be feasible for SpaceX to shut up all the "Starlink satellites are blocking my view of the sky" complaints by launching a Hubble-equivalent space telescope (not more capable, just more modern and presumably much cheaper) and then giving out observation time on it.

Of course, it would not be easily maintainable given we no longer have the space shuttle, but if the majority of the cost was development, the manufacturing + launch costs today might make replacement cheaper than on-orbit repairs.

https://www.space.com/15892-hubble-space-telescope.html claims "Getting Hubble developed and launched cost $1.5 billion".

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There's a lot of limitations with an on orbit satellite you don't run into with ground based systems. Hubble is pretty old and it's mirror pretty small at this point so there are hard limits on it's usefulness for viewing very faint objects, it's mirror simply doesn't gather as much light because it's relatively small at just under 8 feet. Another thing you can't do anywhere nearly as easily are upgrades or adding new experiments. With ground based telescopes it's relatively easy to add new experiments on the side mirror to measure new spectra or measure in a different way. That just can't be done with a space based telescope, even if the design allowed for it the costs sky rocket.

It doesn't gather as much light as ground based telescopes, but the background (for example, from airglow) is also much lower, so the SNR is pretty good.

That's one of the reasons for building in the Atacama desert. Also, the adaptive optics technology has pretty much removed the majority of the negatives from the atmosphere.

What's SNR?

An abbreviation for “signal-to-noise ratio” that imo should have been StNR or simply S/N. (Thus I sympathize with not parsing it immediately — it is widely used, though, so it is good to know.)

https://en.wikipedia.org/wiki/Signal-to-noise_ratio_(imaging...

With a telescope integrated into Starship, you could potentially land the whole telescope from orbit and do repairs and upgrades on the ground. Whether the main mirror can withstand launch and reentry is a question though

EDIT: found a counterargument: https://www.scientificamerican.com/article/elon-musks-starsh...

That also depends on how Starship can actually open which they've been pretty vague on for larger payloads. It seems difficult for it to open in a way that gets the bottom half of the front of the ship out of the way (because of the heat shield). If you can't fully clamshell that open you might still need expensive and delicate origami to unfold the main mirror and any sun shields to get them a clear view of the sky.

That's setting aside the costs of actually running it too as brought up in the article. Maybe that can be brought down but there's necessarily going to be more complexity and more specialized workers required to run a space telescope vs a ground telescope. It'd be interesting to see where the extra costs come from; the specialized people monitoring the satellite, downlink time, etc. Some could get brought down but seems difficult to make it cost competitive with having a similar telescope on the ground.

Dont starlink constellations have to be replaced every few years, maybe a decade tops? So theyre being launched constantly. Just throw your new fangled sensor on the next one, no need to upgrade.

That's completely unworkable... Starlink sats are tiny and by being replaceable you don't want to put extra expensive equipment on them. There's not the space to put the primary and secondary reflector you need. So far we don't have a way to do the same kind of synthetic array with visible light we can do with radio waves. Even once we get past that issue you still have the light gathering issue of small reflectors where the kind of extremely dim objects astronomers are most interested in can't be imaged properly with small reflectors.

Starlink sats also want to keep their bottom pointed at the ground at all times because that's where all the fancy radios live while telescopes need to freely point and track their targets.

> shut up all the "Starlink satellites are blocking my view of the sky" complaints

These complaints make a lot more sense when you project forward by just a few decades. We're talking about _one_ provider already causing minor hassles. What do you think an entire commercialized segment is going to do?

Maybe we can shut up all the "LEO satellites are the best way to build a communications network" people by building out a reasonable and fair network on the surface of the earth first.

> We're talking about _one_ provider already causing minor hassles

We are already at two providers (SpaceX and OneWeb), soon three (Amazon's Kuiper). But I guess that's your point

> Maybe we can shut up all the "LEO satellites are the best way to build a communications network" people by building out a reasonable and fair network on the surface of the earth first.

Didn't we already try that for the last ~200 years? With intensified focus towards internet specifically since the dotcom bubble. All evidence points to this being really hard for a mix of economic and political factors that are unlikely to be swayed by astronomers

> Didn't we already try that for the last ~200 years?

A significant portion of this time was spent with humans using horses to travel.

> All evidence points to this being really hard for a mix of economic and political factors

What evidence is that? This is purely anecdotal. Here's a better question, why are there so few cellular providers in the USA? Does 4 seem correct to you? Does it really seem like we've exhausted all our terrestrial options?

We know how much new Hubble would cost. The Roman telescope is based on donated donated spy satellite of similar size and design. It will cost estimated $3.2 billion and that doesn't include the mirror and structure.

New Hubble telescope wouldn't solve the Starlink problem. There are lots of smaller ground telescopes that have view blocked. We would need to launch a bunch of smaller, like 1m ones, to compensate. Also, there are a lot of larger telescopes that are only feasible on Earth. Good example is the 8.4m Rubin survey telescope which is only going to cost $700 million but would be lots of billions in space. That might fit in Starship but the Extremely Large Telescope won't.

>The Roman telescope is based on donated donated spy satellite of similar size and design. It will cost estimated $3.2 billion and that doesn't include the mirror and structure.

Is that using same company that is refurbishing $40m SSME engines at $420m per engine? 10x the cost of new one 24 years ago, or 20x the cost of whole Raptor launch? Or the company building $2.7b launch tower, a Launch Tower at twice the cost of Burj Khalifa?

https://caseyhandmer.wordpress.com/2024/10/02/sls-is-still-a...

It's not just people trying to use telescopes to do science, it's also people like me trying to do astrophotography. Time on a LEO telescope, while cool, would not help my photography.

As an astrophotographer myself, Starlink has caused me 0 issues. I'm not sure if that's what you're trying to imply. Airplanes are the biggest issue but are easily edited out.

Um, how in the world would a LEO telescope not be the ultimate series in your photography collection?

The hobby is the process, not the photograph.

That said, Starlink affects the process only for about an hour after sunset and another hour before sunrise. And there are so many other things affecting that process that Starlink is neigh negligible. Well, actually, photographing Starlink itself is very satisfying and beautiful and a challenge in itself.

I don't think that people actually making these complaints are in the hobby.

So, the process of deciding what to image, pitching the idea as worthwhile, getting approved for scope time, and then getting the results to present how you want to would be underwhelming for you? As an amateur? You've got some pretty high standards if so.

You and I both know that if this were to happen, it would be the first gallery of where ever you host your results. It would be framed on your wall somewhere. It would be the story you told everyone about.

I love the "hobby" as well as it pretty much forces me to get out into nature well away from city lights. But I would absolutely do all of the things above and behold it as the crown jewel of hobby achievements.

That's a completely different hobby.

"Oh, you like golf? Have you considered paying a pro to give you one of their old scorecards? It'd be the best score in your collection!"

No, it's more like you got permission to play on course you don't normally play having Tiger Woods as your caddy using his clubs and then you get to make the score card say whatever you want. But only if you really want to buy into the premise your response made any sense in the conversation

Do you... not buy into that premise that my comment makes sense in context? I thought it was pretty clear.

The issue I take with your new scenario is that you're not the one swinging the club. You've been working on your stance, grip, and follow-through, but none of that is relevant because the clubs Tiger uses are 400 feet long and in space.

And how is this any different from people that are more advanced in their hobby with a setup in a remote location[0] with better viewing that your home so that just type in a few commands for their gear to start working and then receive an email/notification when things are done?

Again, your premise is just strange. If you are using an auto-guide setup tracking on its own, then you're really not working the hobby as if you had your eyeball on the eyepiece manually tracking a guide star on an alt/az mount instead of equatorial mount. At this point "hobby" is really undefined in context, so saying that someone with more expensive toys is any less of a hobby than someone with less expensive gear is just moving the hole while someone is on the tee box to continue with this wild comparison

[0] https://nmskies.com/

Unless you built your camera and your telescope yourself im not really seeing the difference

If you do grind your own mirrors, more power to you, I've thought of taking up the hobby myself.

Even without grinding your own mirrors, a lot of thought can go into the sensor, telescope, tripod and tracker, filter selection, exposure times, etc. Some of that transfers, some doesn't. Not to mentions the hardships like lugging all your stuff to the nearest desert and staying up checking on your shots and swapping filters. Necessary? Maybe not. A point of potential pride? Maybe.

Also I do happen to know at least one guy who grinds his own stuff. Legend.

One thing that is possible to do is to take multiple photos instead of a single long exposure and then merge them filtering satellites out.

The quality overal will likely be better to, as the noise level can be lowered. It's possible to do a better denoise with temporal info than simply averaging the noise like a long exposure does.

I've written here before with some back of the envelope numbers for a hubble 2.0 + starship as the LV. It gets more interesting if you set up an assembly line for cameras in a tube like the hubble to spread the costs out, and use newer guts for the sensor payloads and on board compute. Make some assumptions about the telescopes, such as being okay to fail since we have so many up tWebb. You could even do experiments in computational photography like the Keck or the VLA to overcome the light collection limits of the mirror size. I forget the numbers I came up with but it's a lot of orbital sensors for the cost of one hubble program and like an entire space station with sensors for the James webb.

What computational photography are you referring to? I've read a fair bit about them but only seen adaptive mirrors and interferometry as some of the great improvements in imaging

Reminded me of this, not sure if anything came out of it.

US military gives NASA two better-than-Hubble telescopes (2012): https://www.theregister.com/2012/06/05/military_gives_telesc...

Some more info:

https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...

They might launch one of them in 2 years:

https://en.wikipedia.org/wiki/Nancy_Grace_Roman_Space_Telesc...

I’d rather just de-orbit every StarLink satellite, stick next gen data satellites in geostationary orbits, and outlaw more any more space trash at that scale in LEO, full-stop.

Latency's not going to stop being a problem for geostationary orbits, which is why lower altitudes get used.

It's a good thing we don't have even more ignorant tyrants in power then

Well, the smart tyrants are certainly making productive use of StarLink, to be sure.

> I’d rather just de-orbit every StarLink satellite, stick next gen data satellites in geostationary orbits, and outlaw more any more space trash at that scale in LEO, full-stop.

Flip side is that stuff in LEO deorbits pretty quicky, while geostationary junk doesn't deorbit in any timeframes humans care about.

A democratic space telescope could be an interesting experiment. Imagine if paying $5/month got you access to all the telescope's observations, and also the ability to vote on where it points next.

Now that we don't have the Space Shuttle maintenance would be trivial. There would be no more involvement of the manned space flight division of NASA at all. The telescope designers would just need to launch something that actually worked, since there is no longer a need to justify a manned spaceflight program.

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