After months of speculation, it's official. The crew of Shenzhou 11 will live aboard the Tiangong 2 space laboratory for 30 days. Add more time in space for them to fly to the laboratory and come home. All things considered, it's a month-long mission.

This mission plan had been suspected for a long time by analysts, but we received a big surprise recently with the crew level. Instead of three astronauts on the mission, there will only be two.

In a previous article, this analyst suggested that the smaller crew level could have been selected to conserve logistics. Now that it's been confirmed that a month-long mission will fly, that seems even more likely. But wait. Tiangong 1 had enough supplies to support three astronauts for roughly a month. Is it really necessary to drop the crew by a third?

It depends on the objectives. The reduced crew will have additional safety margins for their supplies. That could be critical if they need to extend their mission. Returns to Earth can be delayed by weather and other factors. Crews also need to wait for favourable "windows" in their orbits for landing if they miss the first attempt. In a worst-case scenario, these factors can keep a crew on an extended mission for days.

Then again, China may quietly be planning a mission that's longer than the advertised 30-day stay. If the crew and the gear are working well, they may stay up for another week or more. The extra logistics would make this possible.

Having only two people on board the fairly small laboratory could also provide improved living conditions.

China is slowly trickling out more information to us on the mission of Tiangong 2. Keep it coming!

earlier report
China to launch second space lab Tiangong-2 in Q3 Beijing (XNA) Feb 29 - China will send its second orbiting space lab Tiangong-2 into space in the third quarter of this year, which is expected to dock with a cargo ship scheduled to be launched in the first half of next year, sources from the manned space program said Sunday.

As part of the country's space lab program, China also plans to launch the Shenzhou-11 spacecraft, which will carry two astronauts on board, in the fourth quarter of this year to dock with Tiangong-2, according to the program's spokesperson.

After its first test flight in the Wenchang satellite launch center in south China's Hainan Province, the Long March-7 rocket will put the cargo ship Tianzhou-1, which literally means "heavenly vessel," into space in the first half of 2017 to dock with Tiangong-2 and conduct experiments.

Dr Morris Jones is an Australian space analyst who has written for spacedaily.com since 1999. Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email. Dr Jones will answer media inquiries.