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Chinese Space Program

Flyaway

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Flyaway

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This article is concerning the Change’e 5 Lunar sample return mission to be launched later this month.


From that article:

Hiesinger hopes that access to the samples will be similar to how researchers access rocks collected by the US Apollo missions— by submitting a proposal to NASA on how they plan to use them.

But Xiao points out that scientists at Chinese institutions cannot access Apollo samples because the US government restricts NASA from collaborating directly with China.
 
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Flyaway

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I saw that but decided not to post it as there was no recovery equipment attached. TBH I was really hoping there would be.
 

Flyaway

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Retrieving the samples will require a complex deep-space ballet. After launch from the Wenchang launch center in southern China, Chang’e-5 will arrive at the Moon about 3 days later, where an orbiter will release a lander. Over the course of 14 days, the lander’s robotic arm will scoop up surface samples and a drill will retrieve cores down to 2 meters. Scientists are hoping for 2 kilograms of material. (NASA’s Apollo program brought back more than 380 kilograms; three Soviet robotic Luna missions returned 301 grams.) An ascent vehicle will ferry the samples to the orbiter, where they will be packed into a re-entry capsule for return to Earth and a touchdown in the grasslands of Inner Mongolia. Xiao says international investigators will have access to the samples, but U.S. scientists may not because of limits on cooperation with China set by the U.S. Congress.
Zou Yongliao, a geochemist at the Chinese Academy of Sciences’s National Space Science Center, says China is making the South Pole the focus of its near-term lunar plans. And although the target site has not been revealed for Chang’e-6, another sample return mission, planetary scientists are rooting for South Pole–Aitken. A basin sample would provide clues to the mantle puzzle. It would also anchor the older end of the crater-counting curve, says Carolyn van der Bogert, a planetary geologist at the University of Münster, and “illuminate the early history of the Moon.”
 
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FighterJock

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Good news that the Chinese are bringing back rocks from the moon (the first rocks since the Apollo moon landings), I hope that they succeed. How many tonnes of rocks are they planning on bringing back Flyaway?
 

Flyaway

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View: https://twitter.com/cgbassa/status/1329430877101830144


HT
@Marco_Langbroek
for the Chang'e 5 navigational warnings for Monday's launch from Wenchang. The orbital inclination appears to be around 22 degrees, with a launch time around 21:00UTC and translunar insertion around 25 minutes after launch, assuming a 3 to 4 day lunar coast.

View: https://twitter.com/cgbassa/status/1329431687516856322


The numbered green +'s in this plot indicate the lunar antipode at different days, e.g. for a 3 day lunar coast, translunar insertion would have to happen at the +3 day point.

View: https://twitter.com/cgbassa/status/1329433593278509058


[quote\For the launch the parking orbit is almost co-planar with the line connecting the antipodes, so the launch time/lunar coast period is not well known yet. See for example the situation for the Chang'e 5T1 mission from Xichang, where the launch time confirmed the 4 day lunar coast.[/quote]
 

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Good news that the Chinese are bringing back rocks from the moon (the first rocks since the Apollo moon landings), I hope that they succeed. How many tonnes of rocks are they planning on bringing back Flyaway?

I can't tell if you're being snarky or not but in case not, the number is in the Science magazine article -- 0.002 tonnes (2 kg). For comparison, the Apollo missions brought back about 380 kg combined.
 

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China's Long March-5 rocket filled with propellant for launch


WENCHANG, Hainan, Nov. 23 (Xinhua) -- A Long March-5 rocket began to be filled with liquid oxygen and liquid hydrogen cryogenic propellant at about 6:30 p.m. (Beijing Time) Monday, said the China National Space Administration (CNSA).

The Long March-5 Y5 rocket, scheduled to be launched from the Wenchang Spacecraft Launch Site in south China's Hainan Province between 4:00 a.m. and 5:00 a.m. Tuesday, will send the Chang'e-5 spacecraft to Earth-moon transfer orbit.

The mission is the country's first attempt to launch a spacecraft to collect and return samples from the moon, the CNSA said.

The launch window is the best time selected through orbit design, considering the factors including the position of Earth and the moon.
 

Flyaway

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Good news that the Chinese are bringing back rocks from the moon (the first rocks since the Apollo moon landings), I hope that they succeed. How many tonnes of rocks are they planning on bringing back Flyaway?

I can't tell if you're being snarky or not but in case not, the number is in the Science magazine article -- 0.002 tonnes (2 kg). For comparison, the Apollo missions brought back about 380 kg combined.
Do you happen to know how much did the Soviets bring back in total with their unmanned missions?
 

TomS

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Good news that the Chinese are bringing back rocks from the moon (the first rocks since the Apollo moon landings), I hope that they succeed. How many tonnes of rocks are they planning on bringing back Flyaway?

I can't tell if you're being snarky or not but in case not, the number is in the Science magazine article -- 0.002 tonnes (2 kg). For comparison, the Apollo missions brought back about 380 kg combined.
Do you happen to know how much did the Soviets bring back in total with their unmanned missions?

In the same article: 301 grams.
 
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Flyaway

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Good news that the Chinese are bringing back rocks from the moon (the first rocks since the Apollo moon landings), I hope that they succeed. How many tonnes of rocks are they planning on bringing back Flyaway?

I can't tell if you're being snarky or not but in case not, the number is in the Science magazine article -- 0.002 tonnes (2 kg). For comparison, the Apollo missions brought back about 380 kg combined.
Do you happen to know how much did the Soviets bring back in total with their unmanned missions?

In the same article: 301 grams.
D’oh. Doesn’t say much for my memory.:oops:
 

FighterJock

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Good news that the Chinese are bringing back rocks from the moon (the first rocks since the Apollo moon landings), I hope that they succeed. How many tonnes of rocks are they planning on bringing back Flyaway?

I can't tell if you're being snarky or not but in case not, the number is in the Science magazine article -- 0.002 tonnes (2 kg). For comparison, the Apollo missions brought back about 380 kg combined.

Not that much as I was expecting TomS, compared to the Apollo moon landings, I thought that they were going to bring back more. Obviously it has to do with the size of storage on the lander itself, It is a mission that I am going to follow with interest.
 

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Flyaway

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View: https://twitter.com/coastal8049/status/1331731513952505864


With Bill Gray's TLE for
@Change5
and some help from Cees Bassa we are able to get a decent estimate of the lunar orbit insertion time.
28 Nov 2020 14:21:27.506 at 3150.669km lunar periapsis.
Note my original guess:

View: https://twitter.com/coastal8049/status/1332032784454467585


#Change5 long arc Doppler analysis from last night with a slight tweak in the orbital elements to get the best fit. Reports from Europe indicate the tweaked TLE is producing good tracking results. This TLE accounts for yesterday's TCM-2. TLE at end of thread.

View: https://twitter.com/coastal8049/status/1332032787990278144


Here's the same data compared to the GMAT model. Frequency difference error is due to spacecraft oscillator drift.

View: https://twitter.com/coastal8049/status/1332032789361741824


1 47097U 20331.49919926 .00000000 00000-0 00000-0 0 08
2 47097 20.9642 2.6808 9586896 227.8366 103.0296 0.09346337 07
 

Flyaway

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View: https://twitter.com/coastal8049/status/1332274087456952322


Ever try to go to sleep and something pops into your head? Here's a method of determining the timings of all major #Change5 mission events and event the orbital elements it will use around the Moon. THREAD

View: https://twitter.com/coastal8049/status/1332274091919777794


From this diagram I made an angle measurement of the LOI to the first lunar orbit change event. 12 degrees. Angles are key to unlocking all the timings. I will detail the process of determining the first orbital timings and elements here.

View: https://twitter.com/coastal8049/status/1332274094025236484


Some math, 12/360 * 29.531 (sidereal period of Moon's orbit)= 0.984367 days.This is significant as the Chinese always want a major mission event to occur over China so one day after lunar orbit insertion places the Moon back over China so they can lower the orbit in view of them.

View: https://twitter.com/coastal8049/status/1332274096311189504


From the mission events diagram they have three complete lunar orbits planned while the Earth completes another rotation to get the Moon back over China... That's a period T= 28350s for each orbit. Semi-major Axis a= 4639.14286km.
 

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View: https://twitter.com/coastal8049/status/1332274098379005954


We know periapsis is 217km therefore Rp (radius of periapsis) from the post below and the inclination of 45.7 degrees. Now solve for Ra (radius of apoapsis) as we know Semi-major Axis of the orbit and calculate eccentricity of the orbit you get 0.57877601

View: https://twitter.com/coastal8049/status/1332274102623637510


Orbital shape is 217x5586km which appears to match this screen grab presented during launch coverage. The remaining elements have been estimated and can be figured out via Doppler analysis once #Change5 arrives at the Moon just like I did with #Change4. That was fun. Now to bed.
 

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