On Aug 22, 2:04*pm, Marvin the Martian wrote:
On Tue, 18 Aug 2009 11:54:06 -0700, Eric Chomko wrote:
On Aug 17, 10:17*pm, Pat Flannery wrote:
And why it's so hard to get
thehttp://thespacereview.com/article/1448/1

Pat

Lemme see, Mars at 36 million miles at its closest and the moon at 250K
miles on average, that is 36 x 4 = 144 times as far. *It takes 8 days to
do a lunar mission. So, if we equate the distance to mission time,
linearly, we have a Mars mission taking 1152 days, 3 years and almost 2
months.

Well, your analogy is bad, it has to do with transfer orbits and the
lowest energy orbit to Mars requires less energy than it takes to get to
the moon and takes about 6 months, not three years.

Yeah, but the moon stays roughly 240K miles from the Earth, whereas
Mars goes around the sun. So your mission to Mars really is one
synodic period between Earth and Mars, timewise.


You have the wrong concept (distance is wrong, energy is correct) and
being totally off by an order of magnitude. But other than being totally
wrong, yes, you're correct.

I said " linearly". You seem to miss the fact that the two year
window is a fact between two planets and their orbits around the sun,
wheareas the moon always stays close to the earth.

Eric