Author Topic: Queqiao (Chang‘e-4 coms relay sat) - CZ-4C - XSLC - May 20, 2018 (21:28 UTC)  (Read 24725 times)

Offline Phil Stooke

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Right - they were released while the Apollo CSM was already in orbit.

Offline Svetoslav

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Thanks, Phil. Before Longjiang-2, what was the smallest satellite to maneuver into Lunar orbit? My bet is for Hiten (early 90s Japanese probe).

Offline Dalhousie

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Quote
#queqiao Chang'e-4 satellite is right now (13:41 UTC/ 09:41 EDT/ 21:41 BJT) expected to flyby the Moon at ~110 km above the surface & head to E-M Lagrange point 2, after a braking manoeuvre. Hopefully we'll get actual updates from China before too long.

https://twitter.com/aj_fi/status/1000008862659948545

The burn has been successfully completed at 13:32 UTC.

Do we know when it will arrive at L2?
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Phil Stooke

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"Before Longjiang-2, what was the smallest satellite to maneuver into Lunar orbit? My bet is for Hiten (early 90s Japanese probe)."

Interesting question!  Hiten was small, but it had an even smaller companion called Hagoromo.  Hiten was not intended to become an orbiter, but it would release Hagoromo during a lunar flyby and the mini-satellite would make a small burn to enter orbit.  But communication was lost when Hagoromo was released.  Did it burn and enter orbit?  Apparently there was optical confirmation of the burn from Earth.  So if that is correct Hagoromo entered orbit.  Mass - not sure if I have that, but quite small.

Only after that, and thinking Hagoromo did not go into orbit, was Hiten repurposed for lunar orbit.  Ed Belbruno and James Miller of JPL designed the low energy trajectory.

Offline gwiz

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Mass - not sure if I have that, but quite small.
8 kg including the solid motor.

Offline Galactic Penguin SST

Quote
#queqiao Chang'e-4 satellite is right now (13:41 UTC/ 09:41 EDT/ 21:41 BJT) expected to flyby the Moon at ~110 km above the surface & head to E-M Lagrange point 2, after a braking manoeuvre. Hopefully we'll get actual updates from China before too long.

https://twitter.com/aj_fi/status/1000008862659948545

The burn has been successfully completed at 13:32 UTC.

Do we know when it will arrive at L2?

News reports during the perilune burn gives the transfer to EML2 time as "around 4 days" so it should arrive around today.
Nothing at all was reported from tjhe Chinese since then. 
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline Phil Stooke

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Sorry, I know this is off topic but just to follow up on the posts above about Hiten:

Canalias, E., Gomez, G., Marcote, M., & Masdemont, J. J. (2004). Assessment of mission design including utilization of libration points and weak stability boundaries. ESA Advanced Concept Team.


http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.194.2043&rep=rep1&type=pdf


"At 19:37 UT on 18 March 1990 (04:37 19 March JST) as Hiten approached its first lunar flyby, the small Hagoromo spacecraft was released into lunar orbit, making Japan the third nation to orbit the Moon.  Although the S-bamd transmitter aboard Hagoromo had failed on 21 February 1990, the ignition of the Hagoromo deceleration rocket was confirmed by ground observation at 20:04:03 UT, the estimated orbit was 7400 by 20000 km with a period of 2.01 days. Six seconds later, at 20:04:09 UT (05:04:09 19 March JST) Hiten reached its closest flyby distance to the Moon of 16472.4 km."

The same source also give the mass of Hagoromo as 12 kg, with context suggesting that should include the motor and/or fuel.

Offline gwiz

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The same source also give the mass of Hagoromo as 12 kg, with context suggesting that should include the motor and/or fuel.
That's right, should have said 8 kg not including rocket in my post above.

I have 9.8 deg as the lunar orbit inclination for it.
« Last Edit: 05/31/2018 08:56 AM by gwiz »

Offline Galactic Penguin SST

Quote
#queqiao Chang'e-4 satellite is right now (13:41 UTC/ 09:41 EDT/ 21:41 BJT) expected to flyby the Moon at ~110 km above the surface & head to E-M Lagrange point 2, after a braking manoeuvre. Hopefully we'll get actual updates from China before too long.

https://twitter.com/aj_fi/status/1000008862659948545

The burn has been successfully completed at 13:32 UTC.

Do we know when it will arrive at L2?

News reports during the perilune burn gives the transfer to EML2 time as "around 4 days" so it should arrive around today.
Nothing at all was reported from tjhe Chinese since then.

It seems that the report above was incorrect and CE-4 Relay will not reach the halo orbit until around 20 days after launch, so probably not for another 10 days.
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline Svetoslav

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Thanks for clarifying. I wondered what's wrong with that lack of information.

Offline Olaf

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https://gbtimes.com/queqiao-update-change-4-lunar-relay-satellite-establishing-halo-orbit-after-approaching-lagrange-point
Queqiao update: Chang'e-4 lunar relay satellite establishing halo orbit after approaching Lagrange point

Offline Olaf

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https://twitter.com/planet4589/status/1002929442854002688
Quote
Report that DSLWP-A1 may not be dead after all. (anyone want to translate the Chinese?). What orbit it's in is another matter...
@LiuyiYiliu
message from Harbin Institute of Technology ,
confirmed already already received the signal from Longjiang1 (DSLWP-A1).
08:06 - 2. Juni 2018

Online russianhalo117

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https://twitter.com/planet4589/status/1002929442854002688
Quote
Report that DSLWP-A1 may not be dead after all. (anyone want to translate the Chinese?). What orbit it's in is another matter...
@LiuyiYiliu
message from Harbin Institute of Technology ,
confirmed already already received the signal from Longjiang1 (DSLWP-A1).
08:06 - 2. Juni 2018
last issued TLE on CelesTrak:
LONGJIANG 1
1 43471U 18045B   18140.97000001 -.00010094  00000-0  00000-0 0  9993
2 43471  27.5020 209.5210 9658153 171.2240   2.0960  0.09844104    18

LONGJIANG 2
1 43472U 18045C   18140.97000001 -.00010094  00000-0  00000-0 0  9994
2 43472  27.5020 209.5210 9658153 171.2240   2.0960  0.09844104    19

Offline Liss

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This message reflects my personal opinion based on open sources of information.

Offline Dalhousie

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Any news of safe arrival?
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Galactic Penguin SST

Any news of safe arrival?

Apparently the arrival date is still around 2-4 days away.
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline Star One

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Any news of safe arrival?

Apparently the arrival date is still around 2-4 days away.

Taking its time. Due to limitations of the launcher?

Offline Phil Stooke

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The faster you go, the more you have to slow down when you get there.  Much better to go slowly and ease into the complex path around L2, with more chance for small corrections to the trajectory along the way.  I get the impression there was some nervousness about this mission, because a lot depends on it, and somewhere I saw that they only had fuel for one attempt so it had to be done right.

Offline Galactic Penguin SST

Any news of safe arrival?

Apparently the arrival date is still around 2-4 days away.

...and that burn has just been completed successfully at 03:00 UTC.

Source
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline Svetoslav

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