Friday, May 15, 2009
As Americans were transfixed by images of astronauts wrestling the
venerable Hubble space telescope into the cargo bay of Atlantis, the
European Space Agency sent two space telescopes to the Lagrange-2 point.
L2 is 1.5 million km from Earth, in the direction opposite from the Sun.
At that point the gravity of the Sun plus Earth gives a satellite an
orbital period about the Sun period exactly equal to that of Earth.
Herschel is the largest space telescope ever launched. It will examine the
universe and the solar system in the far infrared, while the Planck
telescope is designed to examine the Cosmic Microwave Background remaining
from the Big Bang. The ESA telescopes will join Kepler at L2. Launched
two months ago by the US, Kepler will search for earthlike planets orbiting
other stars. In a few years, other telescopes, both US and European will
join the search for answers.
Because of the risk, the final Hubble repair mission was initially
scratched by NASA. The American public wouldn't hear of it. I was the
recipient of some of the public irritation after WN was quoted in some
newspapers this week saying the shuttle was "at the root of Hubble's
problems." How could I say such a thing? Without repairs by shuttle
astronauts Hubble would have been abandoned at birth as a nearsighted
failure. Let me explain: the hero's welcome given the Apollo astronauts
persuaded NASA that there should be astronauts on every mission. It was
decreed that nothing was to go into space except by means of the shuttle.
That included Hubble, which had to be designed to fit in the cargo bay, and
worst of all, it had to go into an orbit the shuttle could reach. That
ruled out the L2 point, which by every measure is the ideal place to locate
a telescope. That is, unless you want to look at Earth; then you need the
L1 point on the side toward the Sun.
Only by projecting a need for almost weekly shuttle flights could NASA
justify such a huge investment. Of course, it never did better than a
flight every two months. In the days before the shuttle, NASA followed a
policy of redundancy; a duplicate was built for every mission. The cost of
making two was only slightly greater than the cost of one. If the first
failed, appropriate changes could be made in the second; if the first
worked fine the second could be sent on a different mission, as in Pioneer
10 and 11, and Viking 1 and 2. The cost of human spaceflight is so great
that it would be far cheaper to send replacements than to make repairs.
Humans, tiny specks of self replicating matter, have succeeded in finding
out just how insignificant we are. It's not enough. We also need to
understand the atoms we are composed of, and how they came to be assembled
into life forms. The LHC may soon explain how the energy of the Big Bang
became atoms. Nicholas Wade in today's New York Times tells us that John
Sutherland, a chemist at the University of Manchester, may have unraveled
the chemistry of the origin of life. We will, at a time perhaps not far
distant, be able to explain everything that exists, but we will still not
know why.
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