Doh!! Jerry Flaherty ----- Original Message ----- From: "Sterling K. Webb" <[EMAIL PROTECTED]> To: "Rob McCafferty" <[EMAIL PROTECTED]>; "Ron Baalke" <[EMAIL PROTECTED]>; <meteorite-list@meteoritecentral.com> Sent: Thursday, January 18, 2007 6:46 PM Subject: Re: [meteorite-list] NASA Spacecraft En Route to Pluto PreparesforJupiter Encounter
> Hi, Rob, > > I see Ron just posted the explanation to you and > the List, but if you like colored line diagrams galore > and equations with delta's in them, take a look at: > http://en.wikipedia.org/wiki/Gravitational_slingshot > > Gotta love those little delta's. Sir Isaac would be > de-lighted. > > The article also explains the "powered slingshot" > when you do a engine burn at closest approach, which > adds the energy of the burn to the energy provided by > the planet, and to the energy the fuel picked up while > falling in. It all goes to the spacecraft, because after > you burn the fuel, it gets "left behind." > > The powered slingshot is why the Earth is a hopeless > candidate for spaceports of the future. You want to go > somewhere else in the solar system? Depart from the > Moon! > > It's got gentle escape velocity, no bothersome draggy > atmosphere, then you drop like a rock in a circumterrestial > orbit that skims the edge of that unhealthy Earth atmosphere. > and do your big burn there. Hello, Mars, Venus, wherever > you want to go! > > I'll be selling lunar condos in the lobby afterward, and > LunaPort construction bonds, too... > > > Sterling K. Webb > ---------------------------------------------------------------- > ----- Original Message ----- > From: "Rob McCafferty" <[EMAIL PROTECTED]> > To: "Ron Baalke" <[EMAIL PROTECTED]>; > <meteorite-list@meteoritecentral.com> > Sent: Thursday, January 18, 2007 4:33 PM > Subject: Re: [meteorite-list] NASA Spacecraft En Route to Pluto Prepares > forJupiter Encounter > > > Jupiter's >> gravity will >> accelerate New Horizons away from the sun by an >> additional 9,000 >> miles per hour, pushing it past 52,000 mph and >> hurling it toward a >> pass through the Pluto system in July 2015. >> > > Could someone clarify something which ahs been > bothering me for years about this gravity assist > technique? > > Why does the spacecraft come out of the gravity well > going faster than it went in without thrust? > > You remember the conservation of energy stuff from > school? GravPotential to Kinetic to GravPotential. A > ball rolling down a hill can only roll up the other > side to a height as high as it was released from. > > Why does this not apply to spacecraft? > It's climbing out of the suns gravity well so it ought > to be slowing down all the way. When you drop into > Jupiters gravity well I can see that you're going to > speed up but on the way out surely it'll lose all that > speed and at the end of the encounter should be no > faster than it went in at. In fact, slower because > it's now further up the hill of the suns gravity well. > > Please, will someone tell me what I'm missing. It > bothers me tremendously that I have a BSc in physics > and studied both astronomy and astrophysics subsids > and I don't get it. > It's the same with asteroids getting ejected into > orbits further out. How? How? > > Sir Isaac would not be amused > > Rob McC > > > > ____________________________________________________________________________________ > Looking for earth-friendly autos? > Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center. > http://autos.yahoo.com/green_center/ > ______________________________________________ > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list > > > ______________________________________________ > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list