Quote:
Originally Posted by Rude Dude
Can someone educate me on the specifics please??
|
The sense of it is this. The Earth's near circular orbit has us moving around the Sun at about 19 miles a second. For us to make a probe fall in close enough to the Sun to get to Mercury's orbit, we need to shed most of that speed (I don't know the exact number, but it is probably around 12 to 14 miles per second). This is almost double the change in velocity required to get to Saturn.
If you did this direct to Mercury flight, the probe would be in an elliptical orbit taking it from Mercury's orbit back out to Earth's. If you wanted to use rockets to slow the probe down directly, you'd need to adjust the probe's velocity to enter Mercury orbit, but this time you'd need to change it much more (IIRC, you'd need to change it by about 30 miles per second).
The trip that Messenger is taking will use *much* less fuel, and require a much smaller rocket than the trip you're asking about. I don't think that a Saturn V could have had enough energy for the direct to Mercury orbit flight with a one ton probe.