Tuesday, April 10, 2012
Retirement of the aging Space Shuttle fleet last summer (WN 8 Jul 2011)
grounded the 62 remaining NASA astronauts. Although the US is one of the 16
partner nations of the International Space Station, an American astronaut
would need a ticket on a Russian Soyuz to get there. The Bush plan was
Constellation, a new program to deliver astronauts and supplies not only to
the ISS, but also to the Moon, to Mars and "other destinations beyond."
Constellation would have indulged all the space-colony fantasies at a cost
that would retard genuine progress. Worse yet, astronauts romping around
Mars would almost guarantee contamination of Mars with terrestrial
bacteria, ending any hope of answering the profound scientific questions
about the origin of life that draw us to Mars. In the end, common sense
prevailed; Constellation was canceled.
On the 40th anniversary of the Bolshevik Revolution, barely a month after
Sputnik 1, a dog named Laika was launched on Sputnik 2. Poor Laika
survived a few hours at most. President Eisenhower shared a remarkable
report with the American people: "Introduction to Outer Space," prepared by
his Science Advisory Committee under the direction of James R. Killian,
President of MIT (http://www.fas.org/spp/guide/usa/intro1958.html) . "The
cost of transporting men through space will be extremely high," it
noted, "but the cost and difficulty of sending information through space
will be comparatively low." A year later, however, NASA chose seven
military test pilots to be the first astronauts, romanticized by Tom Wolfe
in "The Right Stuff." John Glenn was picked for the first orbital flight,
but NASA first sent Ham, a chimpanzee, to test the water. In spite of his
lack of test pilot experience, Ham did everything John Glenn would do.
Both Ham and Glenn would end up in Washington: Glenn in the U.S. Senate,
Ham in the National Zoo.
The Mars Science Laboratory, including a new Mars rover, Curiosity, was
launched 26 Nov 2011 from Cape Canaveral by an Atlas V rocket. It's
scheduled to land on Mars at Gale Crater near Mount Sharp on 6 Aug 2012.
The primary objective is to determine whether Mars has ever supported life.
Curiosity is about five times larger than the Mars rovers, Spirit and
Opportunity, and uses far more sophisticated instrumentation. Its
designed to explore for at least one Martian year (687 Earth days) over a
range of 5-20 km. Instead of solar panels, Curiosity relies on an RTG
(Radioisotope Thermoelectric Generator) for power, allowing it to operate
at full power night and day, unaffected by dust collecting on its surfaces.
The isotope of choice is Pu-238, an alpha emitter with an 87.7 year half-
life that generates about 0.5 watts/gram. According to the March 23 issue
of Aviation Week, U.S. production of Pu-238 was halted in 1988 and supplies
are dwindling. NASA and the Department of Energy expect to restart
production of Pu-238 in six or seven years and for the first time use the
isotope more efficiently in the Advanced Sterling Radioisotope Generator.