Free of Earth generated interference and orbiting Starlink satellites, the far side of the moon now has a space based telescope in a halo orbit taking observations.
The instrument, called the Netherlands-China Low Frequency Explorer (NCLE), is located on Queqiao, a Chinese communications satellite that was launched in support of the Chang'e 4 mission, the first soft-landing and robotic mission to the lunar far side. NCLE was developed in the Netherlands by Radboud University, ASTRON, and ISISpace, along with support from Netherland's Space Office.
The satellite's orbit keeps it in the L2 Lagrange point (the L2 Lagrange point lies in a line through two masses, on the far side of the smaller of the two).
Until now, Queqiao provided telecommunications service for the Chang'e 4 mission, acting as a relay station between the Yutu 2 lander and China's project control center on Earth. The Dutch-Chinese telescope radio telescope has been dormant since it was launched in May 2018. The NCLE device was supposed to have been deployed a few months ago, but it was delayed owing to the tremendous success of the Chang'e 4 mission, which wasn't expected to last beyond March 2019.
The China National Space Administration (CNSA) has now decided to move on to the next stage of the mission and convert Queqiao into an observatory for radio astronomy, according to a Radboud University press release. Three antennas have now been partially unfurled, allowing for radio scans of space—without pesky interference from Earth's atmosphere.
NCLE is hoped to detect 'super-faint' radio signals in the 80kHz to 80MHz frequency range from the universe's 'Dark Age'- the period just after the Big Bang and before star formation began.
(Score: -1, Offtopic) by Anonymous Coward on Tuesday December 03 2019, @05:30AM (1 child)
SoylentPolitics is the world's finest online community of wealthy sexagenarians.
Vote Libertarian Republican.
Kill the poor.
Money makes right.
Take from the young and give to the old.
Donate your life savings today, right the fuck now.
Eternal Motto: Fuck You, Got Mine, Give Me Yours.
SoylentPolicy: Worldwide death penalty, no discussion, firing squad, for the crime of inconveniencing old people.
(Score: 0) by Anonymous Coward on Tuesday December 03 2019, @02:53PM
Come on, this is radio astronomy. Don't mess it up with politics talk.
(Score: 0) by Anonymous Coward on Tuesday December 03 2019, @05:31PM (3 children)
The L2 point is on the far side of the Sun-Earth system and has nothing to do with the Moon. I don't think they are talking about the Earth-Moon L2 point (or the Sun-Moon L2 point, for that matter).
(Score: 0) by Anonymous Coward on Tuesday December 03 2019, @09:03PM
This satellite is in a halo orbit around the Earth-Moon L2 point.
(Score: 2) by The Shire on Wednesday December 04 2019, @01:19AM
I'm assuming this business of being on the "far side of the moon" is because at some points in the lunar orbit the moon will be showing it's "dark side" to the L2 point.
L2 btw is also the future home of the James Webb telescope, assuming it ever gets off the ground.
Not sure why the jab at the Starlink satellites. They are not a concern no matter what orbit a space telescope is in. I'm 100% sure no one in that program said "We better put this in orbit or we'll have to deal with Starlink". The rationale for putting a telescope in space isn't because of earth satellites, it's because of atmospheric and surface conditions.
(Score: 0) by Anonymous Coward on Thursday December 05 2019, @06:14PM
Pretty sure they mean the Earth-Moon L2 point.
(Score: 2) by VanessaE on Tuesday December 03 2019, @05:35PM (5 children)
I'm a little confused, or maybe it's just because the various linked articles fail to explain: how are we getting data to and from this satellite, if it's parked in Earth-Lunar L2? What's serving as the relay?
(Score: 2) by Common Joe on Tuesday December 03 2019, @06:11PM (4 children)
I had to look this up myself.
Apparently, there's multiple Lagrangian points. The L2 is 4 times further away from the earth as the moon is from the earth. The moon would pass between the earth and the telescope.
Article about the L2 point is here [esa.int].
(Score: 2) by VanessaE on Tuesday December 03 2019, @06:35PM (3 children)
Sure, that makes sense, but the main article says the observatory/telescope is at the Earth-Moon L2 point, not Earth-Sun's L2. Thus, the moon would be between the observatory and Earth at all times; it would be stationary from the observatory's point of view.
So, since the moon blocks RF, there must be something else that gets a periodic view of Earth to serve as a relay. Is there another satellite in a normal lunar orbit?
(Score: 1, Informative) by Anonymous Coward on Tuesday December 03 2019, @09:08PM (2 children)
The satellite is in a halo orbit around the Earth-Moon L2 point. This puts it some ~65k km behind the Moon from Earth's perspective. The halo orbit makes it look like it's running circles around the Moon and puts it in Earth's view most of the time so that it can be used for communication. Originally the satellite was used as a communication relay for Yutu, the Chang'e 4 rover on the Moon's rear side but now the radio observatory is also activated since the rover did its thing. For now the lunar nights will be used for doing the initial observations and later this should be extended to full-time operation.
(disclosure: engineer involved in the project here)
(Score: 0) by Anonymous Coward on Tuesday December 03 2019, @09:11PM
See here for an earlier article with some info on how this halo orbit works: https://www.skyandtelescope.com/astronomy-news/dutch-radio-antenna-hitches-ride-chinas-moon-relay-orbiter/ [skyandtelescope.com]
(Score: 0) by Anonymous Coward on Tuesday December 03 2019, @10:23PM
I'm aware that L2 points are only "quasi-stable", but how stable is the Earth-Moon L2? I imagine the Sun is more than a minor perturbation at the Earth-Moon L2, or at ANY Earth-Moon point.
(Score: -1) by MyOpinion on Thursday December 05 2019, @01:33PM
This is all imaginary: "space", as described in this story, cannot exist as it is a second law of thermodynamics violation.
Gas needs to be contained, and it will ALWAYS expand to fill in ALL of its container. This is a fact of life.
Truth is like a Lion: you need not defend it; let it loose, and it defends itself. https://discord.gg/3FScNwc