The future of terrestrial astronomy is bright. And that’s bad.
The sky is rapidly filling with fast-moving satellites reflecting sunlight and zapping the astronomer’s detectors. After all, it’s very difficult to see faint galaxies in distant space when someone shines a flashlight into a telescope.
The biggest culprit is SpaceX, which launched a large and growing constellation of Starlink Internet satellites since 2018. Of the total of more than 7,500 satellites in orbit around the Earth, more than 3,900 are Starlinks, which means more than half of the birds orbiting Earth. Raise the SpaceX flag.
These satellites are already threatening astronomy. Many telescopes, especially those conducting wide-angle surveys of the skies looking for Earth-threatening asteroids, are seeing their observations marred by bright satellites crossing their field of view. Failure to detect these may result in false positives. It may take a lot of effort to discover that what was initially thought to be real is in fact not.this will only get worse The more Starlinks fly. 12,000 are planned, and SpaceX is applying for an additional 30,000 more than that. If this happens, the sky will be filled with flying satellites.
But in a potential irony, SpaceX CEO Elon Musk has argued that the cure may also be to blame for the devastation. The company is currently testing a giant Starship rocket that, if it works as planned, will have the ability to launch very large and heavy payloads. Musk said it could be used to send large telescopes into space above the Starlink constellation, alleviating pollution problems and ushering in a new era of widespread space-based astronomy. said.
Historically, Mr. Musk has made many claims on a wide range of subjects with no or no results. For example, his flawed Hyperloop plan, nukeing the poles of Mars to create atmosphere, or basically anything he promised on Twitter. In general, these claims are not just unrealistic. It also lacks the specifics needed to actually do it.
The same applies to his idea of a revolution in space-based astronomy. This claim is (to put it generously) naive. As with many such claims, feel It’s correct, but it doesn’t stand up to scrutiny. In a nutshell, what Starship can do for astronomy is certainly great, but by no means is she an all-encompassing solution to Starlink’s problems.
Much of the cutting edge of astronomy is done using very large telescopes, some with mirrors 8 meters or more in diameter. At the moment, there is no rocket capable of launching a monolithic mirror large enough to reach space.
Both the American Delta IV Heavy and the European Ariane 5 rockets have a payload fairing (the part at the top of the rocket that surrounds what will become the space telescope) with an inner diameter of about 5 meters. These are two of the largest rockets in flight, but unfortunately both are scheduled for retirement (and the planned next-generation Ariane 6 has some development issues). Either way, neither is large enough to accommodate the largest telescopes.
NASA’s gigantic space launch system now has fairings of similar size, and in future planned configurations, fairings with an operating diameter of about 9 meters can carry a whopping 130 tons of weight into orbit. can. But its launch costs are prohibitively high, well over $2 billion.
Starship’s current fairing width is about 8 meters (future versions will extend to 10 meters), and the maximum length is about 17 meters. It will rise to low earth orbit at a height of 100 tons. Spacious enough to accommodate a large telescope. It’s not clear how much Starship will cost to launch, but less than $100 million wouldn’t be unreasonable. At a press conference in February 2022, Musk said the cost could drop to around $10 million in a few years, but his claim should still be taken as a Mars-sized nugget of salt. .
It’s clear that Starship can significantly reduce launch costs. However, for most space telescopes, especially large space telescopes, launch costs are not a significant portion of the lifetime cost. For example, Hubble’s long-term cost has exceeded $16 billion (in 2021 dollars), and launching the space shuttle cost about $1 billion. JWST’s projected price is about the same, with a launch cost of about $200 million.
Lowering launch costs is a good thing, but it only puts pressure on the budget. Operating in space is much more difficult than on the ground, and the overall cost increases by an order of magnitude, so most of the funding goes to the development and construction of the telescope. For example, the much larger 10-meter Fukkek telescopes in Hawaii cost about $90 million each (at $1991).
To be fair, the reason space telescopes are so expensive to develop right now is that they have to fit big telescopes into tiny fairings. The JWST had to be folded and shoved into the Ariane 5 fairing and unfolded in space like a 10 gigabak origami experiment, something that had never been done before and cost significantly more. Increased. With a larger fairing, that wouldn’t have been possible (although it should be noted that the tennis-court-sized awning needed to keep the infrared telescope cool would still need to be folded). The Starship’s heavier weight limit also means that technicians don’t have to shave every ounce possible from the telescope. A sturdier, heavier frame could potentially be used at a much lower cost.
But this is a very large scale, but it certainly costs a lot of money to operate a space telescope. Hubble ground operations are about $100 million a year and JWST is $172 million a year. The Keck telescope costs just $16 million. Clearly, the additional cost of just using a space telescope will quickly outweigh the savings in launch costs.
Musk’s claims of an astronomical revolution do not explain how dozens of ground-based small telescopes still have a major impact on astronomy. They are much cheaper to build and operate. Many major universities have telescopes or use telescopes that they manage by joining consortia like the Association of Universities for Research in Astronomy. Tens of thousands of his Starlink satellites degrade the quality of observations. Replacing them with space-based telescopes is neither reasonable nor feasible.
Assuming Starship works as promised, it’s clear that space astronomy has a very exciting future (the first test flights had some serious problems; was not, but it is still not clear whether it was simply the result of an untested rocket or a serious flaw in its design and launch that made it doomed). However, Starship is a double-edged sword, not only can it launch large telescopes, but it can also deploy a huge number of Starlink satellites.
Space telescopes were never intended to replace terrestrial observatories, nor can they. They work complementary, but both are required. Whatever benefits Starship brings to the telescope, it’s literally not a panacea for her growing Starlink problem.
Author’s note: Thanks to the astronomers and “orbital cops”. Jonathan McDowell We thank him for his help with some of the figures in this article.
This is an opinion and analysis article and the views expressed by the author are not necessarily those of the author. Scientific American.
