Scientists and technicians are considering three possible extra missions for Chang'e-2, but no final plans were yet decided.The first was staying in the lunar orbit, continuing to transfer data back to the earth for further research before eventually landing on the moon as an experiment for future lunar probes.In the second scenario, Chang'e II would leave the Earth-Moon system, flying into outer space to test China's capability to probe further into space.The third would be a "homecoming," altering its orbit to become an earth orbiter.
Quote from: Satori on 10/01/2010 11:42 amScientists and technicians are considering three possible extra missions for Chang'e-2, but no final plans were yet decided.The first was staying in the lunar orbit, continuing to transfer data back to the earth for further research before eventually landing on the moon as an experiment for future lunar probes.In the second scenario, Chang'e II would leave the Earth-Moon system, flying into outer space to test China's capability to probe further into space.The third would be a "homecoming," altering its orbit to become an earth orbiter.I saw that news item too. The 'landing' could only be an impact mission, the probe has no terminal guidance system and I believe the thrusters aren't strong enough to hover even if it did. But it would be helpful for low-orbit navigation practice.If there is enough excess delta-V to achieve earth-Moon escape (as Clementine did) that's good for the flag-waving but without a transmitter built powerful enough, and ground tracking dishes with enough sensitivity, it's hard for me to imagine how long they'd be able to keep contact, especially in the continuous full sunlight conditions (recall their anxiety about overheating when CE-1's orbit entered full sunlight briefly, on its mission?).
The earth-Moon escape scenario would be the more ambitious for China and could give them some experience in deep space tracking.
Quote from: Satori on 10/01/2010 11:52 amThe earth-Moon escape scenario would be the more ambitious for China and could give them some experience in deep space tracking.Compared to their scheduled Mars hitch-hiker mission? Several years ago, the practive would have been useful. Now it will conflict with the Mars mission requirements.
After my post yesterday morning (UK time) I discovered that because of some quirk in this new-fangled Vista-thingey, some software that was giving perfectly good data under Windows XP is now churning out rubbish.Oh well, I suppose it’s called “progress”. I have now re-run the software on my XP machine and got some decent results!At the time of the Chang'e 2 launch the lunar GHA was about 66 degrees and this, combined with a launch inclination of 28.5 degrees indicates a transit time between trans-lunar injection and lunar orbit injection of ~115 hours: this is more in line with the Chinese saying that the trip will take five days.The transit time means that lunar orbit injection should come on October 6th at about 06:30 GMT, and at that time the lunar GHA will be around 300 degrees. As a comparison, when the first lunar orbit injection burn for Chang’e 1 took place the lunar GHA was 288 degrees, so therefore the estimated time for the Chang’e 2 burn seems to be reasonable.That’s what I like – consistent data! The numbers never lie, but incompetent operating systems can make them appear to do so!