On Monday, China successfully sent the latest in its Chang’e missions on its way to the Moon. Chang’e 5 is the most ambitious to date and, if successful, will make China just the third country to return samples from the lunar surface (after the Soviet Union and the US). While the mission is quite complex with lots of potential for things to go wrong, it’s also happening on a short schedule, so we’ll have a good idea of how things are going within three weeks.

There and back again

China’s Chang’e program, named after a goddess of the Moon, started back in 2007 with the launch of the Chang’e 1 orbiter. Over time, the missions have gotten increasingly complex. Chang’e 3 saw the deployment of a rover on the lunar surface, and Chang’e 4 made history with the first landing on the far side of the Moon. Already, the missions have produced exciting scientific data and lots of photos of previously unexplored areas of the Moon.

Now, China plans to get something back from the Moon that can’t be distilled down to a string of ones and zeroes. As with two earlier missions, once Chang’e 5 reaches lunar orbit, it will deploy a lander to the surface. But this time, the lander will be accompanied by a sample return vehicle. After using a drill and scoop to load that up with up to two kilograms of material, the sample return vehicle will lift off from the lunar surface and rendezvous with the vehicle that brought it to the Moon.

Once the sample return vehicle and orbiter are reunited, the samples will be transferred to a re-entry capsule, and the orbiter will return to Earth. The re-entry capsule will then separate from the rest of the hardware, and the samples will touch down in the Inner Mongolia region.

All told, the mission is impressively complex. It will require a soft landing, successful rover deployment, sample gathering and storage, a liftoff from the Moon, in-orbit rendezvous, and safe return to Earth—all of them managed remotely. That means multiple steps for things to go wrong, with the mission terminating unless everything goes right. If handled successfully, it will provide yet another indication that China has become a major player in Solar System exploration.

A tight schedule

In any case, we’ll know soon. China’s National Space Agency expects that the entire mission will last 23 days, although the rover has imaging capabilities and will remain active after it’s done collecting samples.

If it’s successful, the lunar samples will be the first returned to Earth since the 1970s. The Chinese National Space Agency already has guidelines ready for the scientific use of any samples that successfully make it back to our planet, and it plans to grant the international community access.

For now, however, all of the hardware is on its way to the Moon after yesterday’s successful launch. The landing isn’t expected for several days, with the sample liftoff from the lunar surface two days after that.

https://arstechnica.com/?p=1725291