Early this morning, in China, the fourth Chinese lunar mission, designated Chang'e-5T (test) was launched from the Xichang launch center. The Chang'e-4 mission had been planned as a repeat the previous lander/rover mission, but was cancelled due to the success of Chang'e-3. The prime objective for Chang'e-5T is to test the ability of a Return Module to come back from the Moon and descend through Earth's atmosphere at high speed and temperature, and land safely. This is a critical capability needed for the planned mission to return a sample of lunar soil on the future Chang'e-5 mission. Over the next eight days, the test Chang'e-5T spacecraft will do a circumlunar flight, going halfway around the Moon, and then come back to land on Earth.
In order to bring the Return Module through the atmosphere from a high speed, Chinese engineers will test what they describe as a "skip reentry," by very carefully and precisely dipping the return vehicle in and out of the atmosphere to slow it down, before having it plunge to land. This is similar to NASA's aerobraking technique, based on the same idea of using the friction of the atmosphere in multiple passes, to reduce speed.
The Chang'e-5T mission Return Vehicle carries a number of samples of organisms into deep space, such as seeds and plants. It will also be the first Chinese lunar mission with a foreign payload on board. The Luxembourg-based company, LUX Space, will have its 4M Radio Experiment on the third stage of the launch rocket, headed to the Moon. The 31-pound experiment will transmit signals from deep space, to engage the amateur radio community in this circumlunar mission. It also carries a tiny instrument to measure the radiation dose on the trans-lunar trip.
As is predictable before any Chinese space launch, there is a plethora of stupid remarks by political pundits. To wit: James Lewis, at the Center for Strategic and International Studies, writes in a UK-based blog that there is little economic or military advantage gained from China's lunar program (!). Joan Johnson-Freese, a professor at the U.S. Naval War College, on the other hand, sees the current robotic lunar missions as a step toward the capabilities China will need for a potential manned lunar program. "Its significance is not only in demonstration of technical abilities," she says, "but in a continued political will to achieve its space goals over long periods of time—that is what China has that the U.S. currently lacks."