The Chinese space agency just launched a man into Earth orbit. The
agency should be congratulated!
This is good news, in that there may be more interesting crewed space
exploration over the next generation. After the landing on the moon,
the US and the Soviet Union stopped interesting crewed space
exploration.
The bad news is that the Chinese space agency choose the same
expensive method for going into space as the US and the Soviet Union.
To some extent, this makes sense as it is cheapest method. It is a
follow up of the 1930s German experiments in `long range artillery
without the gun barrel', and is known to work. Moreover, launching a
human into space is difficult.
Sadly, the cost of this method is always high. It is expensive to
throw away a precision instrument, the rocket, after one use; and the
energy densities of chemicals mean that rockets will carry small
payloads.
>From a military point of view, cost does not matter, since the goal is
to build a device that can destroy an enemy city. One rocket is
cheaper than 1000 manned bombers, as were used for city raids in World
War II. (In World War II, the US used flights of 500 to 1000 manned
bombers to destroy 62 cities and two flights of one bomber each to
destroy two more cities, using nuclear weapons.)
However, for rockets, from a human travel point of view, the price has
to come down. That means using air augmented rockets. With such
rockets, oxygen is taken from the air for the first part of the trip.
Because the rocket does not have to carry all its own oxidiser, the
effective specific impulse doubles.
(Nuclear thermal rockets built and tested on the ground in the US
triple the effective specific impulse. However nuclear thermal
rockets release fission products into their exhaust, and when
launched, some will crash. So earth-to-orbit nuclear thermal rockets
are a bad idea. In space nuclear rockets are a good idea; but the big
issue is how to get from earth to orbit.)
Unfortunately, air augmented rockets are more expensive and risky to
develop than traditional rockets. No one has developed them, although
the idea has been around since at least the 1950s.
Also, I suspect that countries that have developed traditional long
range rockets want to keep them expensive. The governments think of
them mainly as a form of nuclear artillery, and don't want the
equivalent of second-hand bombers being purchased by less rich foreign
nations. If rocket flights were cheap, many rockets would be built.
Eventually, they would be sold. There is no difference between a
civilian freight and passenger carrying rocket and a military one. In
both situations, the purpose is to carry mass into orbit. The mass
could be civilian passengers or a re-entry vehicle with a warhead.
Anyhow, my hope is that the Chinese launch will lead to more interesting
exploration over the next generation.
--
Robert J. Chassell Rattlesnake Enterprises
http://www.rattlesnake.com GnuPG Key ID: 004B4AC8
http://www.teak.cc [EMAIL PROTECTED]
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