China Wants To Launch a Moon-Orbiting Telescope Array As Soon As 2026 (space.com) 32
China is planning to deploy a constellation of satellites in orbit around the moon to create a radio telescope that would enable the study of radio waves longer than 33 feet, providing insights into the "Dark Ages" of the universe. Space.com reports: The array would consist of one "mother" satellite and eight mini "daughter" craft. The mother would process data and communicate with Earth, and the daughters would detect radio signals from the farthest reaches of the cosmos, Xuelei Chen, an astronomer at the China National Space Administration (CNSA), said at the Astronomy From the Moon conference held earlier this year in London. Putting such an array in orbit around the moon would be technically more feasible than building a telescope directly on the lunar surface, a venture that NASA and other space agencies are currently considering as one of the next big steps in astronomy.
"There are a number of advantages in doing this in orbit instead of on the surface because it's engineeringly much simpler," Chen said during the conference. "There is no need for landing and a deployment, and also because the lunar orbital period is two hours, we can use solar power, which is much simpler than doing it on the lunar surface, which, if you want to observe during the lunar night, then you have to provide the energy for almost 14 days." He added that this proposed "Discovering Sky at the Longest Wavelength," or Hongmeng Project, could orbit the moon as early as 2026.
A telescope on the moon, astronomers say, would allow them to finally see cosmic radiation in a part of the electromagnetic spectrum that is impossible to study from Earth's surface: radio waves longer than 33 feet (10 meters), or, in other words, those with frequencies below 30 megahertz (MHz). "If you are looking into the low-frequency part of the electromagnetic spectrum, you'll find that, due to strong absorption [by Earth's atmosphere], we know very little about [the region] below 30 megahertz," Chen said. "It's almost a blank part of the electromagnetic spectrum. So we want to open this last electromagnetic window of the universe."
"There are a number of advantages in doing this in orbit instead of on the surface because it's engineeringly much simpler," Chen said during the conference. "There is no need for landing and a deployment, and also because the lunar orbital period is two hours, we can use solar power, which is much simpler than doing it on the lunar surface, which, if you want to observe during the lunar night, then you have to provide the energy for almost 14 days." He added that this proposed "Discovering Sky at the Longest Wavelength," or Hongmeng Project, could orbit the moon as early as 2026.
A telescope on the moon, astronomers say, would allow them to finally see cosmic radiation in a part of the electromagnetic spectrum that is impossible to study from Earth's surface: radio waves longer than 33 feet (10 meters), or, in other words, those with frequencies below 30 megahertz (MHz). "If you are looking into the low-frequency part of the electromagnetic spectrum, you'll find that, due to strong absorption [by Earth's atmosphere], we know very little about [the region] below 30 megahertz," Chen said. "It's almost a blank part of the electromagnetic spectrum. So we want to open this last electromagnetic window of the universe."
Uneven gravity gradient (Score:1)
I was under the impression after reading about it that the moon's gravitation field wasn't very uniform and therefore made satellites in orbit need to spend a lot of fuel staying in orbit. How are the chinese going to tackle that if I am not misinformed?
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How are the chinese going to tackle that if I am not misinformed?
They aren't ... this is all talk
You must have been living in a cave for the past 30 years. For the past 30 years, after China announced they are going to do something, they get it done. It had happened with Beidou, with their space station, with their moon landings and Mars landings. China already announced they are going to do human moon landing by 2030, so sending a few satellites to the moon before that would serve as a great proof of technology.
The country that kept announcing space plans but unlikely to follow through is USA, amon
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Russia has announced but failed to deliver on more space missions that either the US or India in the last two decades.
Re: Uneven gravity gradient (Score:2)
wants.
china wants a presence on the moon.
I want a pony.
which should I believe is more realistic
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I am glad you asked, made me look it up!
The answer is yes, it is unstable but it is possible and there are "things" orbiting the moon right now. Unless you believe the moon landing was faked...
Re:Uneven gravity gradient (Score:5, Informative)
But the real answer is no - you only looked up a subset of a special case. While there is a general stability problem with very low lunar orbits (below 100 km) which is of interest for satellites observing the Moon's surface, even here there a four "frozen" orbital inclinations that are stable (27, 50, 76, and 86). The radiosatellites do not need such ridiculously low orbits as they are not observing the Moon at all.
Also commenters here should learn to avoid "slashdot disease" - automatic dismissal of everything as being "obviously flawed" by just skimming TFS. Things that pop into your head as possible problems probably have solutions already figured out by the people who spent time working on it (university press release posts are an exception though).
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What?
Nevermind. Typical elite slashdotter response, telling people they are wrong, without fully explaining themselves. Next, when asked to explain properly, they either decline to respond or say "it's obvious" *eyeroll*
Re:Uneven gravity gradient (Score:5, Interesting)
The Earth's irregularities are caused by things like large magma intrusions too, but also low-density areas such as deep sedimentary basins. As such, they've been a tool for oil exploration (and academic research - but it's oil that paid for the R+D) since the early 1950s.
The irregularity of the Earth's gravitational field results in things like GPS systems needing to have a mechanism for distributing updated ephemerides (detailed descriptions of the satellite's obits) to receivers piggy-backed on the timing signals that convey the actual positional data.
In both the Earth and Luna cases, the solution is simple - don't fly your satellites close to the ground if you can avoid it. Which would be the solution that any Lunar radio telescope would adopt. In practice, if you wanted to maintain a constant relation between the radio telescope, the Earth's sources of RF noise, and a large, Moon-sized, lump of rock, you'd probably end up putting the system at Earth-Moon L2 [wikipedia.org] - alongside JWST
Satellites like Mars' "Reconnaissance Orbiter" [wikipedia.org] probably have the same sort of problems, but the updating of ephemerides happens by internal emails at NASA, not by a public radio broadcast.
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The reason for putting this telescope in lunar orbit or on the surface is to use the Moon itself as a shield from the enormous amount of radio noise coming from the Earth at these frequencies. This project is stuck with a low orbit.
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The project is stuck (actually is based on) a lunar orbit, but not a "low orbit" as in the
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This project is stuck with a low orbit.
The project is stuck (actually is based on) a lunar orbit, but not a "low orbit" as in the below 100 km orbits used for lunar surface observation. Since the Moon's radius is 1740 km an orbit of 500 km, say, would provide excellent shielding without being anywhere near the masscon anomalies.
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I was under the impression after reading about it that the moon's gravitation field wasn't very uniform and therefore made satellites in orbit need to spend a lot of fuel staying in orbit. How are the chinese going to tackle that if I am not misinformed?
You are misinformed. There is no need to spend fuel staying in orbit, objects in orbit just stay there as they experience no drag to slow them down. Variations in the gravity field only mean variations in the orbital radius as it goes around the Moon. Any such astronomical system would have very precise positioning (just as we have on Earth now, down to the centimeter or even less) to make all necessary adjustments in data.
long march, belts & roads make for glorious na (Score:2)
That's nice but.. (Score:2)
Can we get a Moon base asap? Skip the Lunar Gateway BS and get us a base directly on the moon.
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A Moon base is probably not worth the effort. Stuff doesn't last long on the lunar surface, because the regoilth is is very sharp due to not having been eroded by wind and wave. It destroys everything. By the end of the 3 day Apollo missions, the space suits and much of the equipment was at end of life.
Since there aren't many natural resources on the Moon, most stuff has to come from Earth anyway. If you are sending regular supplies, and using re-usable rockets anyway, you might as well just send people al
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There are an awful lot of resources on the moon, including oxygen, silicon, iron, magnesium and oxygen. All the stuff you need to build structures and solar panels. There's probably not much need to live there to get it though.
The 7G mobile network will do too (Score:2)
with antenna frequencies going above 50Ghz in order to enable 1TB/s data transmissions can also act as a huge 33 feet antenna.
Could be something else. (Score:2)
Why lunar orbit? (Score:2)
I'd think anything above geo-sync (26,199 miles) should do the job fine, and be a lot easier. Put something at 30,000 miles up and you have a nice stable orbit that has plenty of room for you to spread out. And it's a lot closer than 240,000 miles, so less requirement for energy to put stuff there, or even to service.
OTOH, I can see a good argument for putting a radio-telescope on the back side of the moon (i.e., to avoid radio noise.). Perhaps the orbits will be designed to use the moon to block out the