Re: Why did it take so long to reach the moon

On Feb 25, 10:54 am, Pat Flannery <flan...@xxxxxxxxxx> wrote:
kosmos...@xxxxxxx wrote:
On Feb 25, 10:15�am, P...@xxxxxx wrote:

I was just looking at the Apollo 15 DVD set. �It showed them flying
over their landing site at GMT 96 hours and something. �that's 4 whole
days after launch. �If they were traveling at 25,000 MPH, they should
have made it in about 10 hours. �Did they slow down along the way? �Do
they orbit earth a few times to check things out or head for the moon
as soon as they're in the right position?

That would assume that they traveled in a straight line from the Earth
to the Moon. They didn't. They traveled in a curve.

They also lost velocity on the way... they started out at 25,000 mph but
that steadily dropped till they passed across the point where the Moon's
gravity became more powerful than Earth's, then fell toward it till they
fired the SM's engine to brake themselves into lunar orbit.
You want your velocity to be as low as possible when you enter the
Moon's gravity field, as otherwise you will have to use more fuel to
slow into orbit around it.

Pat

That is true enough, and of our missions getting there within as
little as 3 days seems to beg for a fully interactive orbital
simulator along with all the fly-by-rocket and payload details that'll
have to add up to working each and every time, or else.

The Earth-Moon L1 is relatively easy to get to/from. The moon itself
is not so to/from easy.
. - Brad Guth
.

Relevant Pages

  • Re: Why did it take so long to reach the moon
    ... �If they were traveling at 25,000 MPH, they should ... they started out at 25,000 mph but that steadily dropped till they passed across the point where the Moon's gravity became more powerful than Earth's, then fell toward it till they fired the SM's engine to brake themselves into lunar orbit. ... You want your velocity to be as low as possible when you enter the Moon's gravity field, as otherwise you will have to use more fuel to slow into orbit around it. ...
    (sci.space.history)
  • Re: How far from abort?
    ... they were traveling at about 25,000 miles per hour toward the moon. ... moon until it reached ~6000 mph ...
    (sci.space.history)
  • Re: Why did it take so long to reach the moon
    ... �If they were traveling at 25,000 MPH, they should ... they orbit earth a few times to check things out or head for the moon ... to the Moon. ...
    (sci.space.history)
  • Re: Special relativity passes key test
    ... Now, returning to special relativity. ... Tell us about the shuttle making a right turn over Buffalo NY, ... you realize that to go from an equitorial orbit to a North- ... Decelerate from 17,000 mph to 10,000 mph, then turn south and decelerate ...
    (sci.physics)
  • Watch Out for Flying Moondust
    ... engines," explains physicist Phil Metzger of the Kennedy Space Center ... are blown out as far as a half a kilometer away, traveling fast enough ... NASA is returning to the Moon in the next decade with plans to ... Lunar spacecraft will be far less ...
    (sci.space.news)