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News briefs: July 10
Posted: Thu, Jul 11, 2002, 8:04 AM ET (1204 GMT)
- NASA selected two proposals for earth science missions this week. One, the Orbiting Carbon Observatory, will track the concentration of carbon dioxide in the atmosphere. The other, Aquarius, will map salt concentrations on ocean surfaces. The two missions, worth $175 million each, are part of NASA's Earth System Science Pathfinder program.
- Solar systems like our own, and not supernovae, may be the source of microscopic diamonds, according to a paper published in the current issue of the journal Nature. Scientists thought such nanodiamonds formed in supernovae, but have failed to find large concentrations of them in cometary dust grains, which should be sources of pristine material that predates the solar system. Instead, nanodiamonds may form in the inner portions of solar systems during the planetary formation stage.
- Engineers at NASA's Glenn Research Center have developed a powerful new electric propulsion system. The 72-kilowatt Hall thruster, designed NASA-457M, can generate just 3 newtons of thrust, but this is 10 times the thrust and power of previous Hall thrusters. Such thrusters are similar to ion propulsion systems used on Deep Space 1 and other spacecraft, but use a combination of electric and magnetic fields, rather than just electric fields, to accelerate ions.
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