In the past couple of weeks, Chinese news agencies and newspapers have carried a number of stories about the upcoming mission. The sources are official with the main one being the China Manned Space Engineering Office (CMSEO).

February 28, Xinhua reported CMSEO as saying the Shenzhou 10 spacecraft final assembly was complete and factory testing was in progress with transport to the Jiuquan launch site being the next stage. Construction of the CZ-2F launch vehicle was said to have been completed along with testing. Astronaut training was reported as on schedule with the launch site, the tracking network and support teams ready to run the mission. Tiangong 1 was also said to be ready and in good condition.

On February 4, the 42.8 degree inclined Tiangong 1 orbit had been boosted to 348 x 370 kilometres to counteract the effects of air drag over the previous few months. It will be back down to Shenzhou's 314 kilometre operating height around the end of July. Only a small adjustment will be needed to make it available a few weeks earlier.

Shenzhou 10's mission will carry on almost precisely from where Shenzhou 9 left off. China has flagged this as the first 'operational' Shenzhou flight. It probably indicates that engineers consider there are no fundamentally new challenges, everything in the programme has either been done before or has an objective that builds on what has already been achieved.

One mission objective is to bring spaceflight to the attention of China's youth and to do this, the crew is aiming to provide an interactive science/engineering lesson from orbit for college students.

Shenzhou 8 and 9 docked with Tiangong 1 by matching its orbit and approaching from in front, and for the manual re-docking of Shenzhou 9, the alternative of approaching from behind was tried.

Shenzhou 10 will match Tiangong 1's orbit but with slightly more eccentricity. Doing this will allow it to come in slowly from below using the vertical "R-bar" approach that is routinely performed by vehicles joining the ISS.

CMSEO's mission description refers to both automatic and manual dockings indicating that, as with Shenzhou 9, the initial automatic docking will probably be followed by undocking part way through the mission and a manually controlled re-docking with the crew then going back inside Tiangong 1 to complete the mission.

In November last year, CMSEO said Shenzhou 10 will fly for fifteen days in the period from July to August. During that time, there are three launch windows, each covering about six days. They open on June 7, July 15 and July 28.

The middle one is probably not a contender as it leads to touchdown late-afternoon/evening in the landing zone, limiting the daylight hours available to recovery crews. The other two lead to near-dawn landings and have the added advantage of retro-fire occurring on the sunlit arc of the orbit, permitting the crew to do a visual check on spacecraft orientation.

In order to match orbit with Tiangong 1, a launch from Jiuquan on June 7 will be late-morning UTC, leading to landing in the early hours of June 22 (also UTC) in Mongolia. An indicator that the mission is on-schedule for this launch window will be if the spacecraft is moved to the launch site during the first few days of April.

Names of the crew will be announced shortly before launch. China will make the choice, probably from a pool of six astronauts, when they have completed training. One snippet made available says that there is a desire to include a female crew member. Shenzhou 9 carried Liu Yang, one of two trained female astronauts, to Tiangong 1 in 2012 but the likelihood of her flying an immediate second mission is low. The prime candidate is Wang Yaping, the second Shenzhou 9 female trainee.

Once Shenzhou 10 has departed, Tiangong 1 will be on its own. There are no further visiting missions planned, and the docking unit will have used up its six rated 'lives'. Tiangong 1's fate will probably be similar to other unwanted spacecraft - to end its days with a controlled, destructive re-entry, and any fragments that make it through the atmosphere will likely end up at the bottom of the southern Pacific Ocean.

There is a more-detailed version of this article with explanatory diagrams and a detailed mission timetable at the zarya.info web site

Robert Christy has been analysing and documenting space events since the early 1960s and currently provides information via his web site