Sunday, April 25, 2010

A Common Sense Human Space Program

I wrote the essay below in response to some conversation among my Space enthusiast friends.

As a eleven year old boy I sat before a television  set  filled with excitement and wonder as the Apollo astronauts explored the Moon. The future held the bright promise of humanity reaching out from the Earth. I expected to see Moon bases, humans to Mars and believed I may even have the opportunity to go to the Moon myself.  None of this was to happen. Instead the human race has been stranded in Earth orbit for nearly 40 years.

It should be obvious to everyone that if the current situation continues that the chances of human activity beyond Earth orbit (BEO) are slim to non existent. What happens is that an American President comes up with a Space plan which has some support during his term.  However the following President is not bound by the past President's policy  so  its abandoned. There have been some exceptions, Nixon's space shuttle survived the Carter administration because it was a case of supporting the Shuttle or abandoning manned space completely.  Reagan's Space Station underwent various chops and changes but President Clinton saved it as a post cold war mechanism for  international co-operation. Plans for missions to the  Moon and Mars however have got nowhere. President Bush I and Bush II both had such plans and both plans have ended in the dustbin of history.

President Obama has now released his Space plan, it has much to recommend it. Having NASA contract out to the commercial sector  the mundane tasks of delivering people and cargo to the ISS is long overdue. It should give a major boost to the space entrepreneurs. However it still leaves humanity  marooned in Earth orbit. There is vague goals of Mars and asteroid missions but no set time table.  The decision to build the HLLV won't happen until 2015. Effectively that will acquire approval of the next President.  What the Obama administration will give us is a lifeboat for the ISS.  The Soyuz has been a perfectly good lifeboat for years, its unclear why another one is needed, especially since the Soyuz will be used to ferry astronauts to the Station anyway.  If one was needed I'm sure the commercial people would have been happy to follow up their space taxi with a lifeboat.

It just has to be accepted the that Moon bases and missions to Mars are not sustainable goals. They are too expensive (especially with the US's trillion dollar deficits) and have no widespread support. There is not going to be any BEO activity if those goals are continually promoted. They need to be set aside for goals which are sustainable. Goals which make sense to people.

Such goals do exist for the ability to send people beyond the Earth is essential to our very survival. The sophistication and technological advancement of our civilization has made us vulnerable to natural threats that would have had little or no impact in the past. Lets look at a none space example. A volcano goes off in Iceland and the world's international travel is in chaos. Had that volcano gone of a century ago it would have only been a concern to the people of Iceland. The Space environment presents us with two threats that can destroy our civilization. 

One is the threat of solar storms. Our Sun is a seething ball of  gas that can send huge eruptions of plasma  towards Earth. The resulting solar wind shock wave  can  completely disturbs Earth's   magnetic field. Such storms  effect our communications and electricity generation. In 1989 a solar storm caused black outs throughout Quebec. But that was nothing compared to the solar storm of 1859. That was so severe that telegraph operators received electric shocks and fires were ignited.  If the Earth was hit by a similar storm today without warning it would cause world wide catastrophe. Power station transformers would be destroyed, communications systems would be useless. It would be an existential threat to our civilisation.

Common sense tells us what's required is to keep the Sun under perpetual  observation so as to provide the earliest warning. A way to do that is to have a large solar telescope , comparable to the Hubble or larger, at the L1 Sun-Earth Lagrange point, about 1.5 million kilometers from Earth. The L1 point is an ideal place for a solar observatory as it will never be shadowed by the Earth or Moon. Thats why there's several sun watching  satellites there already. A large aperture telescope would have the resolution to observe the  smallest feature  on the sun providing early warning. Like the Hubble the solar telescope would be man tended allowing  regular maintenance and upgrades. That way the observatory would be available for decades.

 Impact events  are another threat.  The threat of  the Earth impacting with an asteroid, comet or meteorite is real and has happened in the past. There are craters like Barringer and Henbury to prove it.  Although the larger impacts are more rare the smaller ones are more common. The Tunguska event in 1908 had a explosive force between 5-30 megaton. That  impact occurred over Sibera. It couldn't do much damage to civilization in 1908, but a 5 megaton blast over Russia today could have serious international consequences.

Its common sense to be prepared for such impacts and to take measures to prevent them. There has been much thought given as to how divert an approaching asteroid but no one is sure. What is certain is that any action is best taken when the asteroid is far away from Earth. A small diversion , requiring the least energy, in the asteroids orbit at distance will be amplified by the time it approaches Earth to hopefully  However operating on an asteroid ten or twenty million kilometers away means there will be a radio time lag to Earth of several minutes. If you are trying to attach a solar sail or position a hydrogen bomb on a rotating asteroid you want someone there to make instant decisions. Not  try to operate robots with lengthy time lags.

These reasons alone justify a human BEO capability. The goals are modest in cost and capability but would significantly increase our abilities in the Solar System. Note too that this modest capability would also enable Moon orbital missions and the establishment of a major astronomical observatory at the Sun-Earth L2 point. With goals based on plain old common sense rather then illusions the human race can finally leave Earth's orbit.

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