Breaking The Silence On Shenzhou
Sydney, Australia (SPX) Mar 04, 2008
In less than nine months, China will probably take the next step in its human spaceflight program. The mission of Shenzhou 7 will produce China's first spacewalk, along with an extended mission involving three astronauts on the spacecraft.
Shenzhou 7 promises to be China's greatest achievement in human spaceflight to date, aside from the historical significance of China's first human spaceflight mission in 2003. We have a lot of reasons to be interested in this flight. But China is doing little to feed our appetites for information.
This author wrote extensively about China's spacewalking plans in 2006, mostly on the strength of a flurry of media disclosures in the Chinese media. It was fun to indulge in the typical sport of linking a few facts and figures together, jigsaw style, and then trying to fill in the gaps. I have not written about the program in more than a year, largely because there has been little else to work on.
We should have expected more disclosures by now. China should have given us photographs of EVA training, or the spacesuits to be used on the mission. But we have seen almost nothing. China recently re-hashed an old artist's conception of its first spacewalk, showing a spacesuit-clad figure emerging from the Orbital Module of Shenzhou, which will serve as an airlock.
This image, released in the state-run media, showed a different sort of spacesuit. Earlier pictures showed a spacesuit that resembled a Russian Orlan suit, but the recent one looks more like an American suit. It's difficult to know what to make of this.
Is the latest image more accurate, or does it just represent an attempt to obscure the real hardware? We won't know until we see the real thing. Other statements on the technique to be used in the spacewalk, discussed later in this article, hint that there could be changes in the suit.
China has dribbled out occasional statements, to indicate that the mission is still on schedule, and the equipment for the flight seems to be performing well in tests. This is encouraging, because the spacewalk will be a highly complex and dangerous task. Even the Americans and Russians, with decades of spacewalking experience behind them, still treat spacewalking very carefully.
It's worth remembering that the earliest EVAs performed by the Soviet Union and the USA revealed that moving astronauts outside a vehicle was cumbersome.
The Soviet Union and the USA each waited roughly four years between their first manned space missions and their first spacewalks. The gap for China, from 2003 to 2008, is slightly longer in time, but much shorter in mission counts. This will only be China's third manned space mission!
But what will happen on the spacewalk? In January 2008, China published statements that seem to indicate the use of an umbilical cord to support the spacewalker. This will not merely be a tether, as used by current US and Russian suits, but a cord providing power and other consumables to the spacewalker. This was described by one article as "less complicated and safer".
But the article does not firmly state that this will be done on the mission. It's hard to know exactly how to interpret this. It could reflect the opinions of some engineers, or an actual design. Did China plan to use a full umbilical all along, or does this reflect a recent change in the design of the EVA suit? Again, we can only guess at this stage.
The January article mentions that "the length of the cord should not exceed 5 meters to avoid getting twisted." This is a fair statement, but it also constrains the movement of the spacewalker.
If the umbilical system is actually used, the spacewalker will be able to access little more than an area around the hatch of the Orbital Module. In the long term, this makes this form of spacewalking of little practical value for repairs, inspections and transfers to other vehicles. But China could upgrade its technology on future missions.
Spaceflight analyst Charles Vick was questioned by this publication about the spacesuit issue. Vick has raised the theory that the Chinese are experiencing technical issues with adapting an Orlan-style spacesuit, based on Russian technology, into the Shenzhou system. Vick suggests that China may not have bought as much "technology transfer" as they had hoped, and must fill in the gaps themselves.
China has been coy about the tasks to be performed on the mission. The spacewalker will apparently tighten bolts and possibly take pictures, but it seems that only a modest program of activities is planned.
This is logical for a first spacewalk. Simply getting outside the hatch is a big achievement. China will probably want to test the ability of the astronaut to manipulate objects in the spacesuit. Of course, there will be posing for the cameras and speeches.
China has hinted that the spacewalk will be broadcast live on television, reflecting a growing confidence in the space program. But the general lack of pre-flight publicity is arguably no different from China's normal level of disclosure for its spaceflight, as Vick has remarked. China will simply carry out its plans at its own pace, and protect its overall spaceflight ambitions with a well-woven veil of secrecy.
China has again raised the issue of a small satellite, to be deployed during the mission. This could be a secondary payload that is simply piggybacking on the Long March 2F launch, but it could be an integral part of the spacewalk. The satellite could carry a camera to photograph the spacewalk from a distance. China's experience with microsatellites gives it a firm basis for carrying out such a mission.
Again, we have been told that there will be three astronauts on board Shenzhou 7. But how many of them will don extravehicular spacesuits and be exposed to space?
At least one astronaut must remain in the Descent Module, which will be pressurized at all times. But I have previously suggested that two astronauts could suit up for the spacewalk in the Orbital Module, with both being exposed to vacuum, but only one stepping outside the hatch into space.
The second astronaut could provide emergency support if the spacewalker gets into trouble. No statement from China clarifies this, or gives reason to dismiss this suggestion. We simply do not know how many people will be inside the Orbital Module when the hatch is opened to space.
Hopefully, China will increase the flow of information in the months ahead. But they really need to prepare the world for their next mission. Publicity for the 2007 launch of the Chang'e-1 lunar probe was fairly good, and the world seems interested in this advanced mission. This should give China reason to open up its doors further on the Shenzhou program.
Dr Morris Jones is an Australian space analyst and writer. He has covered the Shenzhou program since 1999. (Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email.)
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