... hree_Weeks_999.htmlShenzhou 8 Mission Could Top Three Weeks
by Morris Jones
Sydney, Australia (SPX) Feb 17, 2011The next flight of China's Shenzhou spacecraft will
last somewhere between 20 and 22 days, according to German sources. The
information was relayed to SpaceDaily by a communications officer at
DLR, Germany's equivalent of NASA. German researchers will fly a
collection of biological experiments on the mission, which is expected
to launch in the second half of this year.
The Shenzhou 8 spacecraft will fly with no crew on board, and will be
sent to rendezvous and dock with China's Tiangong 1 space laboratory,
expected to be launched at some time before Shenzhou 8 flies. The
descent module of Shenzhou 8 will return to Earth at the end of the
flight, carrying the experiment package.
The duration of the mission is noteworthy. This will be the longest
flight ever for a Shenzhou spacecraft in its full capacity. It also
gives clues to how China will send astronauts to the Tiangong 1
laboratory, and other space laboratories to follow.
The primary purpose of the Shenzhou 8 mission is to test rendezvous and
docking procedures in space. It's also a dress rehearsal for the
Shenzhou 9 mission, which is expected to carry astronauts to the
Tiangong 1 laboratory in 2012. Thus, we can expect the overall mission
plans to match each other fairly closely.
China has openly discussed its plans for sending astronauts to its first
space laboratory for years, but has released few specific details on
One question that has preoccupied analysts is the expected duration of
an expedition to Tiangong. The space laboratory is fairly small, and
offers little room for astronauts to inhabit. Questions have also been
raised about the logistics of such a mission.
The Tiangong laboratory and the Shenzhou spacecraft that will dock with
it have fairly limited room for supplies. Issues of food, water and
oxygen supplies would almost certainly rule out a long stay aboard the
laboratory.This writer, along with other analysts, has previously
suggested that a crewed flight to Tiangong of roughly two weeks was
likely. Some analysts suggested around three weeks. A three-week mission
for Shenzhou 8 supports all these estimates, but still doesn't tell us
exactly how long the Shenzhou 9 mission will last.
If Shenzhou 8 is meant to be a shakedown cruise for a crewed expedition,
it will try to be thorough in its testing. This means that we can
expect this to cover all of the normal requirements for a crewed
mission, plus a bit more. So Shenzhou 8 is probably going a bit further
with its endurance, to prove that it's spaceworthy for a long time.
This mission is probably designed to last a few days more than will be required for a crewed flight, just for good measure.
If this is the case, then astronauts will probably stay aboard Tiangong 1
for roughly two weeks. A stay of around two and a half weeks is
At this stage, it is unclear how long Shenzhou 8 will fly alone at the
start of its mission, while it approaches Tiangong 1. It's possible that
they will copy current Russian strategies, and cruise for about two
days to the laboratory.
However, China is also introducing a more powerful version of the Long
March rocket to launch this mission, and may opt for a more direct
trajectory. If crew consumables are scarce, it makes more sense to get
to the laboratory as quickly as possible.
Then again, Shenzhou 8 is doing this for the first time, and it's also a
modified vehicle. There will probably be a solo "shakedown cruise" in
orbit before the spacecraft is cleared to move on to the docking phase
of its mission.
On a crewed flight, the time spent in transit will influence the time
available on the laboratory. But we can't be sure if Shenzhou 8's cruise
will match that of Shenzhou 9.
So, we can probably say for sure that crewed expeditions to Tiangong 1
will last no longer than three weeks. Exactly how much time will be
spent on board the laboratory is unclear. But the mission plan suggests
that China is determined to get as much crew time on the laboratory as
it can, given the resources available.