Other science - including some MDIS imaging (i.e. non-movie taking) was done on the approach. The movie seen here was done (obviously) after closest approach. With the amount of calibration activities that they had to do for the swing by, there was only so much time they could devote to taking the movie.
Actually it's a combination of *decreasing* velocity (each flyby will take speed away from the craft, causing it to have a smaller orbit) and the final position in orbit (the final orbit has to be very ellipitcal, and very near polar).
The number of times around the sun is merely a side effect of a) the number of flybys needed and b) the fact that Messenger needs to orbit for a while before it can reach the planet needed for flyby.
The planet does indeed spin - Mercury rotates on its axis 1.5 times per solar orbit (see http://www.solarviews.com/eng/mercury.htm). Because of this 3:2 resonance, a Mercury solar day (sunrise to sunrise) is equivalent to 176 Earth days.
This gives the spacecraft many passes over the light and dark side of the planet, so much that they can spend one (Mercury) day doing global mapping and the second (Mercury) day doing targeted science investigations.
In terms of heat - the highly elliptical, near polar orbit is designed so that the heat shield always faces the sun, giving the instruments a nice room temperature setting on the other side of the shield. There is the possibility of heat from the surface, but the instruments are designed to take that into account.
The above poster is correct, I believe. I don't work on Messenger, but from what I've seen and from this page Messenger's orbit is highly elliptical, with it's sunshield always facing the sun (duh) so the main components should have time to cool down why at the peaks of the orbit (i.e. when it is not looking at Mercury).
I use to work with nanotubes, ao I'll throw in my 2 cents. Nanotubes are still very much in their infancy (only about 10 years old) and research is just now getting to coming up with production techniques that produce decent yields. Unfortunately, there is no current way to choose the style (i.e. chirality) of tube, so it's impossible to get all conducting tubes, for example. We're sorta stuck without that capability, but things are starting to look up.
Fortunately, lots of research money is being put into nanotubes each year, and the scientific community still sees them as a very viable material in the near future (for exactly what or when is still unclear).
Lots of good work is going on at UNC-CH for those of you that are interested.
-Gilthalas
Slashdot Mirror
Other science - including some MDIS imaging (i.e. non-movie taking) was done on the approach. The movie seen here was done (obviously) after closest approach. With the amount of calibration activities that they had to do for the swing by, there was only so much time they could devote to taking the movie.
Gilthalas
Actually it's a combination of *decreasing* velocity (each flyby will take speed away from the craft, causing it to have a smaller orbit) and the final position in orbit (the final orbit has to be very ellipitcal, and very near polar).
The number of times around the sun is merely a side effect of a) the number of flybys needed and b) the fact that Messenger needs to orbit for a while before it can reach the planet needed for flyby.
The planet does indeed spin - Mercury rotates on its axis 1.5 times per solar orbit (see http://www.solarviews.com/eng/mercury.htm). Because of this 3:2 resonance, a Mercury solar day (sunrise to sunrise) is equivalent to 176 Earth days.
e sign.html.
So what this means is that for every Earth year Messenger is orbit, 4 Mercury Years will pass, which consists of 2 Mercury Solar Days (see http://messenger.jhuapl.edu/the_mission/mission_d
This gives the spacecraft many passes over the light and dark side of the planet, so much that they can spend one (Mercury) day doing global mapping and the second (Mercury) day doing targeted science investigations.
In terms of heat - the highly elliptical, near polar orbit is designed so that the heat shield always faces the sun, giving the instruments a nice room temperature setting on the other side of the shield. There is the possibility of heat from the surface, but the instruments are designed to take that into account.
The above poster is correct, I believe. I don't work on Messenger, but from what I've seen and from this page Messenger's orbit is highly elliptical, with it's sunshield always facing the sun (duh) so the main components should have time to cool down why at the peaks of the orbit (i.e. when it is not looking at Mercury).
I use to work with nanotubes, ao I'll throw in my 2 cents. Nanotubes are still very much in their infancy (only about 10 years old) and research is just now getting to coming up with production techniques that produce decent yields. Unfortunately, there is no current way to choose the style (i.e. chirality) of tube, so it's impossible to get all conducting tubes, for example. We're sorta stuck without that capability, but things are starting to look up. Fortunately, lots of research money is being put into nanotubes each year, and the scientific community still sees them as a very viable material in the near future (for exactly what or when is still unclear). Lots of good work is going on at UNC-CH for those of you that are interested. -Gilthalas