Tuesday, April 19, 2016

China in Space 2016

Since 2005 I have had the pleasure of being an expert commentator on China Central Television (CCTV) for “civil” space missions, including both the manned flight program (Shenzhou and Tiangong) and their series of Chang-e lunar probes.  After a three-year lull in Chinese manned spaceflight activity, that program is set to resume this fall.

Since the 3-person Shenzhou 7 mission in 2008, Chinese manned spaceflight has centered on the Tiangong 1 space station module.  This module, announced on CCTV in 2008, and originally slated for flight in 2010, was launched into orbit on 29 September 2011 on a Long March 2F booster.  (The delay in launch date was further extended by a safety review occasioned by the launch failure of a Long March 2C booster in August.)  The module, similar in size and weight to a Shenzhou spacecraft, although very different in design, weighs in at about 8.5 metric tonnes. 

The first visit to TG1 was by an unmanned spacecraft (Shenzhou 8) launched on 17 November 2011, a precursor mission to test all systems before human occupation of the module.  The spacecraft remained attached for 12 days before SZ8 was recalled to Earth.  Several months later, on 16 June 2012, three Chinese astronauts (“Taikonauts”), including one woman, Liu Yang, were launched into orbit on Shenzhou 9.  The flight featured two docking events with TG1, one computer-controlled and one manually-directed, with return to Earth after 11 days.  The Shenzhou 10 mission, also with a crew of two men and one woman, Wang Yaping, flew a year later, launching on 11 June 2013.  After a 15-day flight, featuring several undocking and docking tests with Tiangong 1, SZ10 was successfully returned to Earth. 

It was originally planned that the Tiangong 1 module would be de-orbited in 2013; however, it still remains in space in April 2016, but is apparently no longer crew-rated.  To replace it, the Tiangong 2 module is scheduled for launch in the third quarter of 2016.  It is apparently a slightly modified version of Tiangong 1. 

Manned missions to Tiangong 2 are planned to begin in October or November of 2016, ending a 41-month hiatus.  

More ambitious human space endeavors await the debut of the Long March 5 booster.  The launch facilities for LM5 on Hainan Island have been completed and on-pad tests of an LM5 rocket (not necessarily a flight article) have commenced.  The first launch of the LM5, long planned for mid-2015, can be expected before the end of the year.  LM5, comparable to the Russian Proton or American Saturn I boosters, will carry payloads of up to 25 tonnes to Low Earth Orbit, permitting direct launch of a large second-generation space station module in the 2020 time frame. LM5 will also have a trans-lunar injection capability of about 8 tonnes, allowing a manned lunar flyby or orbital mission with a crew of two or three, followed by return to Earth.  It is likely that such a mission would be preceded by Earth reentry tests of unmanned Shenzhou capsules at lunar-return velocities (11 km/s).  The energy dissipated during a return from the Moon is twice that of the same vehicle returning from LEO, so two-step reentry profiles such as skip-glide trajectories may be expected.  The development of these capabilities will mirror the Soviet Zond probe development program using the Proton booster: Kosmos 146 and 154 tests in March and April of 1967 of lunar manned-mission hardware, the Zond 4 launch into high Earth orbit in March 1968, the Zond 5 launch in September 1968, a “cabin” carrying a dummy cosmonaut for an unmanned flyby of the Moon and return to Earth, and Zond 6 in November 1968 for a similar lunar flyby mission and recovery.  By the usual conservative standards of the Soviet space program, three consecutive successful unmanned tests would be required before launching a cosmonaut on the same mission profile.  The launch pad turnaround of two months meant that the next (and final) unmanned precursor would probably be expected in January.  But the American Apollo program was ahead of schedule, and in December 1968 the Apollo 8 mission was dispatched on a lunar-orbiting mission: 48 tonnes, three astronauts, and days in lunar orbit.  Zond 7 was not yet ready to fly its mission: one cosmonaut at best (and probably none), 6.6 tonnes, on a lunar flyby without orbiting the Moon; embarrassingly non-competitive.  In the heat of the space race, Zond 7 was simply put on indefinite hold.

Zond 7 was finally launched in August 1969 as a repeat of the same unmanned mission profile, a month after the American Apollo 11 mission landed Neil Armstrong and Buzz Aldrin on the Moon; too little and too late.  

Upcoming Shenzhou missions to Tiangong 2, beginning with Shenzhou 11 this November, will practice rendezvous and docking activities, develop experience with longer mission durations, and prepare the way for Moon-oriented manned missions in the Long March 5 era.  Operating without the frenzied intensity of the Space Race, China can progress deliberately and cautiously, minimizing uncertainties and risks, on its own schedule—and using 21st century technology.  Watch for the emergence of a Chinese manned lunar flyby (or orbiter) mission once LM5 is operational, well before manned lunar landing hardware has been developed.  And watch for unmanned precursors, especially high-speed reentry tests!


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