Chang'e 3 prelaunch through lunar orbit insertion, Lander instruments, capability, development, testing, launch Options

[Explorer1]

The Pacific!
Even spinning the final stage to look back at Earth; they sure know how to put on a show! Look at that curvature!

[kenny]

They are saying it is now in an Earth-Moon transfer orbit with an apogee of 360,000 km, so Chang'e 3 is successfully en route to the Moon. Congratulations!

Wonderful colour video of the probe separating, manoeuvring with attitude control jets, sunrise over the Pacific, etc.

[craigmcg]

The best coverage I've seen a a launch. Well done!

[climber]

I segond that!

[dilo]

[Damn, I missed all! Could someone give me a replay link? Thanks!

[Thorsten Denk]

Look here:
CNTV (english)

Thorsten

[dilo]

Thanks Denk! Separation is really spectacular, even though I suspect that, initially, the glare is due to a solar reflection and not to the probe thrusters!
There is also a shorter video with many dramatic views of liftoff:
http://www.youtube.com/watch?v=ctTBRWMh3yw

[kenny]

They have reported that the landing legs, which were tucked under the spacecraft for launch, have been deployed. The four gold colored footpads can be seen
in the section of the movie showing the separation of the spacecraft from the final stage of the launcher. Also, the solar panels are open. Chinese TV have stated
it will land "in 2 weeks".

The last time we saw a new location on the lunar surface from ground level was Jan 1973, with Luna 21 and the Lunokhod 2 rover. So here's hoping!

[kenny]

Separation is really spectacular, even though I suspect that, initially, the glare is due to a solar reflection and not to the probe thrusters!

I don't think that intense brightness is solar flare. The craft apparently has 8 x 150N thrusters in addition to the small attitude control thrusters of 10N each, plus
the main descent engine.

" These eight 150N thrusters are likely used for smaller Trajectory Correction Manoeuvres during the Earth-Moon transfer and small orbital adjustments (&
possibly during LOI and landing). "

Chang'e 3 technical description

I think the flare is us seeing those intermediate thrusters ensuring adequate separation of the probe from the rocket stage.

[dshaffer]

I don't think that intense brightness is solar flare. The craft apparently has 8 x 150N thrusters in addition to the small attitude control thrusters of 10N each, plus
the main descent engine.

" These eight 150N thrusters are likely used for smaller Trajectory Correction Manoeuvres during the Earth-Moon transfer and small orbital adjustments (&
possibly during LOI and landing). "

Chang'e 3 technical description

I think the flare is us seeing those intermediate thrusters ensuring adequate separation of the probe from the rocket stage.

I believe the Lander was "yawing", so the flaring was caused by reflection off the side (shiny surfaces).
You can tell by the thruster firings just before, that indicate a change in attitude.

[djellison]

I think the flare is us seeing those intermediate thrusters ensuring adequate separation of the probe from the rocket stage.

No - the way the flare appeared - from the one, sunlit side of the spacecraft as both spacecraft and third stage entered into sunrise - it was lens-flare of a specular reflecting on gold MLI.

[kenny]

Happy to stand corrected on the flaring....

Latest announcement says Chang'e 3 performed its first course correction manoeuvre about 7 hours ago (3:50pm Beijing time),
when it was 138,000 km from Earth. It is well on its way, and seems to be functioning properly.

[charborob]

Spaceflight 101 describes Chang-e 3's mission and instruments. See under "Lander cameras" for a description of the cameras installed on the lander. Here is the pertinent information:

-------------
"In addition to its three Pancams, the lander is equipped with a single Descent Camera that was tested on the Chang’e 2 spacecraft. The Micro-CMOS camera provides images of 1,280 by 1,024 pixels during the descent to the lunar surface. Details such as exposure times and frame rate have not been given.
The nadir-facing camera is expected to be active when the lander is hovering 100 meters above the surface of the Moon, taking images of the landing site to help rover mission planners to select drive routes later in the mission. The camera is likely taking images all the way down to the surface as the lander makes its constant low velocity descent to an altitude of 4 meters for engine shutdown.
Previous Chang’e missions also included a range of engineering cameras to obtain images and video of important activities of the spacecraft such as solar array deployment and main engine burns. Whether Chang’e 3 also includes such cameras is unknown."
------------

Looks like there is a "MARDI-like" camera on the lander.

I just hope China makes the photos public.

[Toma B]

Some news are coming in:

Chinese lunar probe Chang'e-3 will not perform a planned third trimming of its trajectory along the earth-moon transfer orbit.
The probe's carrier, an enhanced Long March-3B rocket, entered the orbit with comparatively high precision, and the first two orbital trimmings were highly exact, which resulted in the probe being capable of meeting the demands of near-moon deceleration and follow-up orbital control," said a statement released Thursday by the administration.
Noting good adaptability in the flying control plan for Chang'e-3, the statement added that "it has been decided that a third orbital trimming is not necessary."
Chang'e-3 has been in normal operation for about 88 hours as of 6 p.m. Thursday, with a distance travelled of nearly 350,000 kilometers.

Almost there.......

[kenny]

Chang'e 3 has completed its lunar orbit insertion, and will stay in lunar orbit for the next 9 days prior to descent and landing.
It is in its planned polar orbit at an altitude of 100 kilometers.

Landing attempt due on December 14.

Chang'e 3 update

Another big milestone in a very smooth mission so far....