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Thread: China's Chang'e 4 mission

  1. #31
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    An article from The Planetary Society written before the lunch gives more information of the mission.

    http://www.planetary.org/blogs/guest...satellite.html

    China's fourth lunar mission, Chang’e 4, is expected to begin on May 21 with the launch of a Long March 4C rocket from the Xichang Satellite Launch Centre in the southwest of China. The launch will carry a spacecraft named Queqiao, which will serve as a communication relay satellite between Earth and the lunar farside. The name Queqiao means "magpie bridge" in Chinese and comes from a Chinese folk tale, a love story about a flock of magpies that form a bridge crossing the Milky Way once a year to reunite lovers known as the Cowherd and the Weaver Girl, as well as their children.

  2. #32
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    The Chinese paper Xinhua has a short video of the launch and more details of the mission.

    http://www.xinhuanet.com/english/201..._137194788.htm

    China launched a relay satellite early Monday to set up a communication link between Earth and the planned Chang'e-4 lunar probe that will explore the Moon's mysterious far side.

    The satellite was carried by a Long March-4C rocket that blasted off at 5:28 a.m. from southwest China's Xichang Satellite Launch Center, according to the China National Space Administration (CNSA).

  3. #33
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    Queqiao will be passing the moon today.

    https://gbtimes.com/queqiao-update-t...ay-to-the-moon

    According to data computed by Bill Gray, an independent orbit analyst, Queqiao was close to 333,000 kilometres away from Earth at time of publishing on May 23 (with the average Earth-Moon distance being 384,400 km).

    Queqiao is expected to reach and swing-by the Moon on May 25, before heading to its destination, the second Earth-Moon Lagrange point.

    Gray told gbtimes that Queqiao will need to perform a manoeuvre to slow its speed as it comes close to the Moon in order to send it towards its intended destination. If not, Queqiao will leave the Moon with as much energy as when it arrived, and go back into orbit around the Earth.

    "We now have Queqiao going past the moon at 110 +/- 54 km at 13:41 UT on 25 May. That's based just on tracking it optically, though, with no knowledge of when it might manoeuvre," Gray said.

    The expected manoeuvre is the next key moment in the Chang'e-4 mission, which ultimately aims to help operate a lander and rover on the lunar far side.

  4. #34
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    Queqiao Chang'e-4 relay satellite has successfully done the breaking as it passed the moon to reach L2.

    https://gbtimes.com/queqiao-change-4...-space-program

    The Queqiao Chang'e-4 relay satellite has passed the Moon and successfully performed a propulsive manoeuvre to slow itself and send it towards its intended destination beyond the Moon.

    The Beijing Aerospace Control Centre (BACC) issued the command at 21:32 Beijing time (13:32 UTC), and by 21:46 confirmed through telemetry that Queqiao had performed the burn and entered a transfer orbit towards the second Earth-Moon Lagrange point, People's Liberation Army Daily reported.

    The spacecraft passed the Moon at 100 km above the surface at closest approach. Failure to perform the braking manoeuvre would have seen the spacecraft head back towards the Earth.

  5. #35
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    China has lost contact with one of the micro satellites but it will have no effect on the Chang'e mission.

    https://gbtimes.com/change-4-lunar-m...-space-program

    Contact has been lost with one of two microsatellites launched along with the Queqiao Chang'e-4 lunar relay satellite following a standard trajectory correction manoeuvre on the way to the Moon.

    DSLWP-A and B, also known as Longjiang-1 and -2, piggybacked on the launch of Queqiao, a relay satellite for a planned landing on the lunar far side, on a Long March 4C rocket from Xichang on May 20.

    Queqiao passed the Moon at an altitude of 100 km on Friday, successfully performing a braking burn to send it towards its intended destination, the second Earth-Moon Lagrange point, from which it will facilitate communications between the Earth and a lander and rover to be sent to the far side of the Moon.

    The Discovering the Sky at Longest Wavelengths Pathfinder (DSLWP) satellites were intended to execute burns to place them in an elliptical (200 x 9,000 km) orbit around the Moon, where they would carry out astronomy and amateur radio tests.

    While DSLWP-B/Longjiang-2 successfully entered lunar orbit, there has been apparently no communication between the ground and Longjiang-1 following a trajectory correction manoeuvre after trans-lunar injection.

  6. #36
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    Some updates on the Queqiao mission. Do not expect any official update from the Chinese government till mid month when the Queqiao satellite will have settled in its L2 orbit.

    https://gbtimes.com/queqiao-update-c...-space-program

    It has been a week since the Queqiao Chang'e-4 lunar relay satellite made its lunar swing-by, sending it on a transfer trajectory towards the second Earth-Moon Lagrange Point (EML2). There have been no official updates from China, so where is the spacecraft now?

    Having launched late on May 20 UTC, Queqiao made its lunar swing-by on May 25, performing a braking burn at 13:32 UTC to send the communications satellite towards EML2, some 60-80,000 km beyond the Moon.

    EML2 is one of five libration points in the Earth-Moon system that allow a much smaller third body to orbit while maintaining its position relative to the larger two, making it a perfect place for Queqiao to perform its main objective.

    Queqiao should have approached the EML2 point by May 29 after two orbital corrections, but no updates have come from China. This has brought confusion, but making the distinction between reaching EML2 and establishing the desired orbit around it helps bring clarity.

  7. #37
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    Spaceflightnow carries information on Queqiao and Chang'e 4.

    https://spaceflightnow.com/2018/06/0...e-of-the-moon/

    A Chinese communications satellite carrying a Dutch radio astronomy instrument launched last month is expected to maneuver into position around a gravitationally-stable point beyond the moon in the coming days, ready to relay telemetry and data between Earth and the Chang’e 4 lander set to attempt the first landing on lunar far side late this year.

    Launched at 2128 GMT (5:28 p.m. EDT) May 20 from China’s Xinhua space center aboard a Long March 4C rocket, the relay probe completed an engine firing as it flew around 60 miles (100 kilometers) from the moon May 25, setting a course for a perch around 280,000 miles (450,000 kilometers) from Earth.

    The relay craft is named Queqiao, which means “magpie bridge” and comes from a Chinese folk tale in which a flock of birds form a bridge across the galaxy to reunite two lovers.

    Queqiao will park itself in a “halo” orbit around the Earth-moon L2 Lagrange point around 37,000 miles (60,000 kilometers) beyond the moon. At that location, the combined effect from gravity from Earth and the moon will keep Queqiao at roughly the same distance as the moon completes each 28-day orbit.

    China developed the Queqiao spacecraft, which weighed roughly 900 pounds (400 kilograms) fully fueled for launch, to link ground controllers and scientists with the Chang’e 4 lander and rover, the country’s next robotic mission to the moon.

  8. #38
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    Is this going to be a rover mission?
    Time wasted having fun is not time wasted - Lennon
    (John, not the other one.)

  9. #39
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    Quote Originally Posted by BigDon View Post
    Is this going to be a rover mission?
    Yes to be launched towards the end of the year.

  10. #40
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    spacenews confirme Queqiao has entered its intended orbit around L2. Also one of the micro satellites has been successfully put into luna orbit but the other one has been lost.

    http://spacenews.com/change-4-relay-...n-lunar-orbit/

    The relay satellite which will facilitate China’s Chang’e-4 lunar far side landing mission late in 2018 has entered its intended halo orbit around Earth-Moon Lagrange point 2.

    The Beijing Aerospace Command and Control Center (BACC) sent commands for the spacecraft to fire its engines at 11:00 p.m. EDT June 13, with the burn complete at 11:06 p.m.

    The satellite will now undergo on-orbit testing of its communications functions, while maintaining a complex Lissajous orbit, which is a three-dimensional irregular curve, rather than a two-dimensional halo.

  11. #41
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    China and Saudi Arabia jointly released photos of the moon.

    http://www.xinhuanet.com/english/201..._137253874.htm

    China and Saudi Arabia on Thursday jointly unveiled three lunar images acquired through cooperation on the relay satellite mission for Chang'e-4 lunar probe.

    This is an important cooperation achievement between China and Saudi Arabia in the relay satellite mission, the China National Space Administration said in a statement.

  12. #42
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    "How China's lunar relay satellite arrived in its final orbit".

    http://www.planetary.org/blogs/guest...explainer.html

    After a 24-day journey, Queqiao, the relay satellite for China's Chang'e 4 lunar mission, successfully entered its Earth-Moon L2 halo orbit. A normal mission to lunar orbit usually takes four or five days, but Queqiao took much longer due to its special orbit. Here's a guide to the spacecraft's long and complicated journey.

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