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



kosmos327@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
.

Relevant Pages

  • Re: Why did it take so long to reach the moon
    ... �If they were traveling at 25,000 MPH, they should ... to the Moon. ... fired the SM's engine to brake themselves into lunar orbit. ...
    (sci.space.history)
  • Roadtrip Report: KY-WV-PA
    ... make this trip, causing me to cancel; of Spike, our dog, who died earlier this ... east, PA Turnpike 576 west (although you are actually traveling northeast), PA ... I drove all the way to I-470 in West Virginia, clinching I-70 in Pennsylvania. ... Nearly all of I-70 in PA has a 55 MPH speed limit, ...
    (misc.transport.road)
  • Re: The speed of light can not be physically constant to all
    ... car traveling at that speed will take 664 years to move 1 millimeter. ... Were one contemplating two planes moving at 200 mph and 400 mph, ... Miles per *second*. ... It travels a 1 ring distance in the lab reference frame, ...
    (sci.physics)
  • Re: Black smoke from a 106?
    ... could be considered 'risks' whist actually driving ... Take the local unlit stretch of unlit derestricted dual carriageway ... Muntjack ran out in front of you you would have to be traveling less ... If one was to travel at 20 mph *you* would then also ...
    (uk.rec.cars.maintenance)
  • Re: Speed Of Light Question
    ... >>Henri Wilson wrote: ... > referring to a speed of one object wrt another? ... 85 MPH means nothing to a luge pilot with jagged ice ... I am also traveling at 850 mph. ...
    (sci.physics.relativity)