When the Shenzhou-7 spacecraft had made 29th orbit, Chinese Taikonaut Zhai Zhigang slipped out of the orbital module and collected after accomplishing a "space walk" the test examples of solid lubricant and solar cell base panel placed outside the orbit module and, when the spacecraft had made 31st orbit, an 88-pound (40-kg) satellite was released, which would circle the orbital module and send back images to mission control command.
For these feats, People's Daily reporters Liao Wengen and Yu Jianbin have had an exclusive interview with Zhao Guangheng, deputy chief designer of China's manned space program's application system, on these amazing experiments and the related topics.
Reporter: For what deliberations do you introduce solid lubricant, and what is its size and how much does it weight?
Zhao: The designed solid lubricant is based on meticulous thoughts and careful considerations from several aspects: The first is to facilitate the spaceman's operation; the second to meet a demand for high efficiency of both spacemen and spacecraft; and the third to ensure that it is safe without any harm to be done to spacemen and it is also reliable in the whole process of the blast-off, in-orbit moving and spacemen's recovery of material.
The installation, in the form of 170 by 100 by 210 mm., weights three kilograms in itself and the specimen recovered is merely 2.3 kg in weight after being removed from the installation seat on the orbit module.
Reporter: Why do you take to use these two types of materials for the space-exposed test?
Zhao: This is China's first-ever space-exposed test of solid lubricant and solar cell panel. These two types of materials have been put in wide use on spaceflight vehicles, and it can be said that there is no choice but to use them on space aircraft.
Common lubricants can be volatile easily in the vacuum conditions and so solid lubricants have to be used. The lubricant used for the test on the space module comprises 11 varieties in four major categories, comprising those we have put to use before or we are now using, and also those we will possibly to put to use in years ahead, including some materrials yet to be utilized overseas.
Solar cells are used in all spaceflight vehicles, and how to make solar cell base more reliable with a longer lifespan, what impact the outer space environment will have on the base materials and what filmy stuff is more suitable for use in outer space? So I feel it imperative to carry out the space test of these materials, a suggestion made by the 8th Academy of the China Aerospace Science and Technology Corporation (CASTC).
Reporter: What environmental factors should we attach importance to the space-exposed test?
Zhao: Close attention should be given chiefly to the impact of two environmental factors: One is the impact of atomic oxygen in rarefied air as the high-speed inflow of atomic oxygen will erode to some extent a polymer that contains inorganic material. The other is the ultra-violent radiation, as many materials in the outer space can possibly decay from prolonged the ultra-violent radiation due to much stronger radiation from ultra-violent light and cosmic rays.
The taikonaut has recovered the installation during his extravehicular activities (EVA) with an implication that related researches will continue on the ground, and it needs to take into account whether environmental factors will impact on materials in the course of experiments. It seems that the two-day-impact of atomic oxygen has been reflected, and ground tests can already back up and testify to this point.
Contents of the future outer space tests are not just confined to this realm. The trial-test has another purpose, that is, to guide ways and means of setting up modules with the help of outer space researches, and the setting up of ground module models will help guide the selection of the future materials and the application in space.
Reporter: How was the accompanying satellite released, and what was its mission?
Zhao: The satellite was released via two methods, that is, by both ground remote control and the hand-control by spacemen. The flight of the small satellite has three tasks to fulfill, namely, to test the in-orbit release technology, to take photos and transmit video images, and to experiment on the technology relating to the accompanying flight.
Reporter: What difficulties and challenges does the accompanying flight involve?
Zhao: Accompanying flight has certain difficulties and challenges. To make sure the satellite moves round the projected orbit, accurate orbit control has to be performed, so that it will be able to attain the goal for the flying around the "no-cooperation target", and this constitutes a breakthrough in technology.
Reporter: what other significances does the accompanying satellite have?
Zhao: As far as a manned space program is concerned, the significance of the satellite released can be shown mainly in the ensuing spheres: the first to monitor all EVA situations of the manned spacecraft so as to provide a test platform of experimental verification of environmental control and life support system (ECLSS) on the manned spacecraft; secondly to provide some experience for spacecraft rendezvous and docking (RVS); and thirdly to greatly raise the capacity of extending the area of space science and space application as we now have composite spaceflight vehicles, both parent and subsidiary spacecraft.
By People's Daily Online
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