Half of all active satellites are now from SpaceX, and may be a problem | Hacker News Reader

Half of all active satellites are now from SpaceX, and may be a problem

sciencenews.org

This is a somewhat misleading article, considering that it fails to mention that Hubble is only vulnerable right now because its orbit has decayed well below its typical orbit and a boosting mission is being worked on.

As for ground based telescopes, there's constant work being done on compensating for satellite streaks, with SpaceX seeming to be in good faith cooperation with the NSF on the matter.

Additionally, a lot of recent discourse on the matter I've come across seemed to be really blowing things out of proportion (eg a few days ago I came across an image on Reddit claiming to be of the satellite streaks when attempting to take a photograph, only for it to turn out to be specifically the frames where there was a streak stacked together, making it seem much worse than it was).

Usually telescopes are studying some narrow patch of sky and the satellites are still more than sparse enough for streaks to be unlikely and quickly passing through if they do happen to occur.

>and a boosting mission is being worked on

By NASA and SpaceX no less

And as far as I'm aware, NASA isn't even footing the bill. It's an entirely privately funded effort where SpaceX and Jared Isaacman figured they might as well do something meaningful while learning to perform EVAs from Dragon.

Note that "crowded" here means objects about the size of a car, standing on average 400km apart from each other.

> By the 2030s, there could be 100,000 satellites crowding low Earth orbit.

To put that in perspective, that would be approximately 12,436,042 km^3 of space per satellite.

Somehow I think this is a pseudo-problem. People like to complain about everything, and they can be quite creative.

Astronomers are one of the smartest people out there. If you know a machine learning trick, they know two. Or ten. All photos they take of the sky are postprocessed, because of the air turbulence. Are these guys trying to tell me that they can't post-process the satellite streaks out of their images? Why? The sky is static, the satellites fly fast. You can just layer 10 frames on top of each other and figure out how the pixels align and what should be in the photo and what should be out. I would think this is just business as usual, after all, you don't want to announce a big discovery of a new celestial body every time a passenger jet passes over your telescope.

> The number of images partially blocked by satellites is still small, the team found, rising from nearly 3 percent of images taken between 2002 and 2005 to just over 4 percent between 2018 and 2021 for one of Hubble’s cameras.

> “Starlink is the densest patch of space that has ever existed,” says astronomer Samantha Lawler of the University of Regina in Canada. "The satellites are constantly navigating out of each other’s way to avoid collisions" [here a reference to a similarly alarmist study from 2009 is cited]

Isn't this the point of putting telescopes in orbit? Starlink seems to at least be trying to reduce the visibility and size of its satellite fleet, but no one's working on cleaning up orbital debris - the best we have now is tracking of fairly large chunks of trash.

We don't want all telescopes to have to be in orbit, though. That would raise the cost of astronomy enormously. Most astronomy is done with ground-based telescopes for pretty solid reasons.

A temporary problem, if cost per kg for launches comes down as predicted in the next few years.

I have doubts. Launch costs aren't the only thing that makes space-based telescopes very expensive.

Having spent the time working on a space telescope design (Worked on making a cubesat amateur telescope during COVID lockdowns) it’s a significant driver of secondary costs beyond the primary “launch cost”. Space telescopes are commonly “volume constrained” not “mass constrained” like how only Ariane 5 had a fairing big enough for the James Web Space Telescope, how Hubble was as big as they could fit in the Shuttle cargo bay, and many other “big science” general purpose “an observatory in space” sort of telescopes end up expanding to fit their launch volume because the main structures are “empty tubes” or folding mirrors, or extending booms (X-ray telescope mirrors are super clever things) and so you end up with everything else around these low density telescopes structures having heaps of mass budget… but then your still looking at vibrations, ruggedness requires mass… and so the circular game of musical chairs with engineering constraints begins… and you do a lot of engineering work to keep your mission on track.

With major reduction in launch costs it becomes a lot more practical to launch smaller more specifically focused telescopes like we’ve seen with Kepler, TESS and CHEOPS, there’s commercial suppliers of professional grade telescopes, which are more than enough for useful research and with ample spare launch mass they could be given the same kind of cushy ride to space that the commercial cameras you see on the ISS got… it’s a bit of work to vacuum rate something but it would be less work than a camera by far given the fewer moving parts… and so then it’s just your instruments… with lower launch costs you can get significantly better science. Astronomical grants routinely cover the development of new instruments for ground based telescopes, and the costs of some of these projects would easily be able to cover the development of a small dedicated space telescope for a smaller version of the same instrument ( not necessarily a loss in capacity given the advantages of a space telescope ) … it’s not going to be the case for every single telescope project… some of the advanced robotically driven fibre optic spectroscopy instruments would be a bit more challenging given that motors in space aren’t as simple as on the ground (lubricants, heat dissipation and all that) but there’s a lot of other work that could “make the jump” and I expect will make the jump once the cost comes down… there’s whole fields of astronomy that are in a tough spot because of atmospheric absorption, notably ultraviolet astronomy, and they’ve eagerly been producing mission concepts for decades.

A non-problem. Hubble is nearing the end of it's lifespan. Future satellites can be put into higher orbit or will contain technology that can compensate.

People don't understand how big and empty space is, even around our planet.

The only people it might impact are amateur astronomers, who aren't exactly making discoveries anymore.

They discover asteroids heading for earth sometimes.

Eg, 2023 BU https://www.nytimes.com/2023/01/26/science/astronomy-asteroi... (discovered by amateur astronomer Gennadiy Borisov)

Not that I disagree overall.

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