Scientists Give NASA Planetary Marching Orders

coondoggie writes "The community and team of scientists that help NASA prioritize space missions has come out with its exploration recommendations for the next decade: get to Mars, explore one of Jupiter's moons and study Uranus. From the report: 'The gas giants Jupiter and Saturn have been extensively studied by the Galileo and Cassini missions, respectively. But Uranus and Neptune represent a wholly distinct class of planet. While Jupiter and Saturn are made mostly of hydrogen, Uranus and Neptune have much smaller hydrogen envelopes. The bulk composition of these planets is dominated instead by heavier elements; oxygen, carbon, nitrogen, and sulfur are the likely candidates. What little we know about the internal structure and composition of these "ice giant" planets comes from the brief flybys of Voyager 2. So the ice giants are one of the great remaining unknowns in the solar system: the only class of planet that has never been explored in detail.'"

Comments

Re:Develop spacefaring technology first

[c0lo]

Mars may not be the best place for humans to go. Mercury for example looks positively inviting in comparison to Mars.

My apologies to throw in some facts on to your dreams, but I wouldn't call Mercury "more inviting".
Atmosphere - 1 nanoPascal (blown away by solar wind), a magnetic field at 1% the terrestrial one => very little protection against hard radiation With an eccetric orbit, the Sun's radiation intensity is between 4.59 and 10.61 times the level on the Earth orbit (on the surface of Mercury, the Sun looks on average almost three times as big as it does from Earth).

Not having a significant atmosphere, there are no chances for aero-breaking. The delta-v between the orbital-speed is 18 km/s that need to be lost for reaching a transfer orbit. Even more, a space vehicle will fall into the Sun's gravitational well, requiring another huge delta-v to compensate if you want to avoid a crash-landing - a trip alone (not even landing) to Mercury requires more rocket fuel than to escape the solar system. Solar-sails you say? Heck, how long can one afford to keep a maned space vehicle in a radiation 5-10 times more virulent than on Earth orbit. Bigger shields you say? Errr.... more rocket fuel to escape the Earth gravitation, I ask?

Heck, even if I would be to accept the idea of Mercury being more inviting, I wonder if we currently afford to give course to the invitation. Cost per kilogram of dead matter transported to:
1. the surface of Mars - US$309,000
2. a fly-by followed by orbiting Mercury (but not landing on it) - US$878,000 (Messenger mission cost/spacecraft mass).

BTW - the orbital insertion of the Messenger spacecraft around Mercury is expected in about 8 days from now (on March 17, 2011 after 6.5 years from its launch) - fingers crossed.