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by Morris Jones
Sydney, Australia (SPX) Jul 16, 2014
Earlier in Space Daily, this analyst presented circumstantial evidence for a future Chinese astronaut mission to the Moon. China seems to be planning a circumlunar flight for the near future, which will involve sending an astronaut around the far side of the Moon without landing.
An upcoming test flight involving a scaled-down replica of a Shenzhou astronaut descent module adds weight to this theory. China would gain a lot of kudos by launching an astronaut to the Moon and back. This feat has not been performed by the USA in more than 40 years, and has never been achieved by the Russians.
How would a Chinese circumlunar mission work? Contrary to some expectations, it would not really require China to develop any major new technologies or hardware. Although China may choose to wait until its new Long March 5 launch vehicles are fully tested and tamed for use, they could opt for a mission plan that uses existing engines and vehicles. This could allow China to fly a circumlunar mission in the mid 2020s. It would also serve as a back-up plan if the Long March 5 proves too difficult to man-rate for astronaut launches.
China would use a modified version of its Shenzhou astronaut spacecraft for the mission. Shenzhou is a spacecraft with three modules: A cylindrical service module that contains rocket motors, fuel tanks, solar panels and other "organs" to keep the spacecraft working. Sitting atop this is a bell-shaped descent module, containing three couches for the crew. Next is the roughly cylindrical orbital module, which gives the crew extra room and also contains a docking system.
China would produce a modified "circumlunar Shenzhou" by cutting out the orbital module to save weight. The single astronaut aboard would have plenty of room inside the descent module, with two other crew members omitted. Take out the extra crew couches, and you have room for supplies and other gear.
Getting rid of the orbital module saves weight, but it requires a substitute. A small docking support structure would be added in its place. This would contain docking systems similar to those normally found on Shenzhou's orbital module. It would contain no pressurized volume and would be fairly small. This structure will also help to integrate the spacecraft to its rocket.
That's the basic circumlunar spacecraft. It would be launched atop a Long March 2F launch vehicle, just like a regular Shenzhou mission into Earth orbit. This time, the lower weight of the new spacecraft would allow the Long March 2F to place the Circumlunar Shenzhou into a higher Earth orbit.
Soon after launch, the Circumlunar Shenzhou will rendezvous and dock with a rocket stage already in orbit around the Earth. This is a special "tugboat" that will propel the vehicle out of Earth orbit and on its way to the Moon. The tugboat rocket uses storable liquid propellants and has a docking collar at its front. It could have been launched as long as a month prior to the Circumlunar Shenzhou.
The tugboat rocket fires at the right moment to propel the Circumlunar Shenzhou out of Earth orbit and onto a lunar trajectory. Soon after it finishes firing, the Circumlunar Shenzhou will separate from it. The spacecraft will then settle into a three-day cruise to the Moon. During the flight, the spacecraft will rotate slowly about its axis to even out the heating of the sun, a form of thermal control known as "barbecue mode".
This was also done on Apollo missions to the Moon. Approaching the Moon, the spacecraft will stop spinning and will position itself for observations of the Moon. The astronaut inside will busily take photos and videos as the Moon grows closer. There will be some navigational rocket firings soon after the Shenzhou swings around the Moon, as the Moon's gravity throws it on a trajectory back to Earth. Then the Shenzhou will settle back into "barbecue mode" for the flight back to Earth.
Approaching Earth, the spacecraft will orientate itself for re-entry. Assuming it wasn't done earlier in the mission, the docking support structure at the front of the descent module will be jettisoned. Then the instrument module will separate. The Shenzhou descent module will then experience a fast and hot re-entry from deep space, before landing on the steppes of Inner Mongolia in northern China.
Can this be done? Let's consider what China has already flown. The Shenzhou spacecraft has five crewed missions under its belt. China also has practice in rendezvous and docking. It can easily build rocket stages. Soon, China will demonstrate the capability to recover a capsule from the Moon. The groundwork for such a mission has been steadily accumulating for years.
The Soviet Union performed similar tests of this mission plan under the "Zond" program. This involved the use of a cut-down version of their Soyuz crew spacecraft (which has a similar design to the Chinese Shenzhou). The Soviets didn't perform any dockings in Earth orbit, but used the powerful Proton rocket to launch the "Zond" circumlunar spacecraft to the Moon in one take.
Proton has enough power to do this, but has reliability problems, and was not considered as safe as the regular booster used for Soyuz launches. This seems to be one reason why the Zond program never actually carried any cosmonauts to the Moon, despite the launch of test flights with animals aboard. Another reason why the Zond program never reached its ultimate goal was the success of the Apollo program in sending American astronauts to the Moon.
The proposed Chinese plan sounds more complex in principle, but would be much safer to implement, and makes use of technology that has already been developed.
The feasibility of a Chinese circumlunar mission is a good reason to take the idea seriously. It seems likely that the Chinese themselves are probably taking it more seriously than some external observers would suspect.
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.
The Chinese Space Program - News, Policy and Technology
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