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NASA Spacecraft Set to Shine Spotlight on Mercury
coondoggie writes to tell us Network World is reporting that NASA will this month see the realization of a mission launched in 2004, sent to explore the planet Mercury. "MESSENGER, launched in 2004, is the first NASA mission sent to orbit Mercury, the planet closest to the sun. But on Jan. 14 it will pass close by the planet and use Mercury's gravity for a critical assist needed to keep the spacecraft on track for its ultimate orbit around the planet three years from now. Still, the spacecraft is also expected to throw back some never-before -seen images, NASA said. The flyby also will gather essential data for planning the overall mission. After flybys of Earth, Venus, and Mercury, it will start a year-long orbital study of Mercury in March 2011, NASA said. "
Here is the actual JPL page for the mission. It's updated every day.
Check the mission pics on the left side as there are some preliminary pics of mercury. They are still a bit blurry.
How many candlepower must that spotlight be? Nuclear powered? Would it really light things up much more than the sunlight?
Poor choice of a metaphor in the heading; had me thinking there was some illumination involved.
Love many, trust a few, do harm to none.
Well, actually, Mercury's low orbital velocity. It's more than Earth's, but when that elliptical transfer orbit reaches Mercury's orbit, the spacecraft is purely hauling ass. It actually takes a negative delta-V to match velocities.
To reach a superior planet (one outside your own orbit) you initiate the transfer orbit with a positive delta-V, then circularize it with another positive delta-V when you get there. For an inferior planet (inside your orbit), substitute "negative" for "positive" in both places.
rj
Theres a lot of significant work in star trackers to do attitude orientation within the solar system, and I'd imagine that as we explore further outward, we'll make decent enough stellar maps that you could determine your orientation from those maps, and also that you could determine the position based on the variations from 'known' configurations. Its just a question of good models and fast computers. A more practical implementation, something that a friend of mine is working on in fact, is the ability to use star tracker data to determine the positions of the planets. Based on ephemeris data (the very refined data made available from JPL regarding the position of celestial bodies) its just a matter of calculation to determine both the position and the attitude of the spacecraft. Of course from what I know those calculations aren't the easiest things, clearly. - A lowly graduate student in Aerospace Engineering