From: Auberon [fskln1@uaf.edu] Sent: Friday, March 05, 1999 3:47 AM To: blue_planet@mpgn.com Subject: [BLUE PLANET] - Re: "Bray, Lee" wrote: > > I'm also going to stick my neck out on this one. As far as I understand > it (not that I have anything other than a mediocre understanding of the > physics) and have read, a spacecraft using a slingshot manoeuvre > actually 'steal' momentum from the body its using, thereby slowing it > ever so slightly and gaining speed itself. See, this is where I say something that's at the limit of my understanding, and Leif corrects me, but I'm pretty sure that with the masses we're talking about, you can count on more energy gain from the GPE of the reaction mass you leave behind. You can do it, but I don't think it's that significant. Now, the really handy thing about getting close to planets is atmospheric braking. Also pretty if you're on the planet in question. -- +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+= "I never get involved in my own life. It's too much trouble" - Michael Garibaldi (Babylon 5) *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message. From: Bray, Lee [Bray@petinf.co.uk] Sent: Friday, March 05, 1999 3:25 AM To: 'Blue Planet List' Hi All, Auberon wrote: > > > Gravity slingshots are basically useless, because you lose as much > > > energy climbing out of a gravity well as you gain going in. If you shed > > > mass in the process, there can be some net gain, but that's really I'm also going to stick my neck out on this one. As far as I understand it (not that I have anything other than a mediocre understanding of the physics) and have read, a spacecraft using a slingshot manoeuvre actually 'steal' momentum from the body its using, thereby slowing it ever so slightly and gaining speed itself. Cheers Lee *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message. From: Robert P. Stefko [rpsst16@pop.pitt.edu] Sent: Friday, March 05, 1999 4:33 PM To: blue_planet@mpgn.com Subject: [BLUE PLANET] - Re: >I'm also going to stick my neck out on this one. As far as I understand >it (not that I have anything other than a mediocre understanding of the >physics) and have read, a spacecraft using a slingshot manoeuvre >actually 'steal' momentum from the body its using, thereby slowing it >ever so slightly and gaining speed itself. That's correct. The spacecraft gains angular momentum from the planet, which loses a corresponding (but inconsequential) amount of angular momentum and moves ever so slightly closer to its star. The gravity assist can modify velocity, both in the sense of increasing speed and changing direction. "The Galileo probe was launched from the space shuttle in 1989 without enough velocity to reach its destination, Jupiter, even on a minimum-energy orbit. NASA engineers swung the Galileo spacecraft past Venus and Earth — twice each — to get up enough speed to coast out through the Asteroid Belt and reach Jupiter. In December 1992, Galileo zipped a scant 109 miles above the south Atlantic Ocean, on its way to its December 1995 rendezvous with Jupiter." — Space Travel: A Writer's Guide to the Science of Interplanetary and Interstellar Travel *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message. From: c718678@showme.missouri.edu Sent: Friday, March 05, 1999 5:18 PM To: blue_planet@mpgn.com Subject: Re: [BLUE PLANET] -Writer's Guide On Fri, 5 Mar 1999, Robert P. Stefko wrote: > Jupiter." — Space Travel: A Writer's Guide to the Science of Interplanetary > and Interstellar Travel This sounds like a useful book. Where did you find it? Who's it by, etc? Later, Eva @@@(* > *)@@@ *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message. From: BIOHZD@aol.com Sent: Friday, March 05, 1999 5:30 PM To: blue_planet@mpgn.com Subject: [BLUE PLANET] - Access Denied Art Hey All, It is my *distinct pleasure* to once again direct you to the "Restricted Access" portion of our website for a new preview of the artwork for Access Denied. We have posted both a completed front panel from the screen (the right) and the cover art for the AD booklet. Matt Strum (screen) and Brian Despain (cover) have outdone themselves. Superlatives fail me, so I leave their deserved praise to your creativity... Jeff Barber Biohazard Games *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message. From: Sean Goodroad [slugman@itis.com] Sent: Friday, March 05, 1999 9:17 PM To: blue_planet@mpgn.com Subject: Re: [BLUE PLANET] -Writer's Guide >On Fri, 5 Mar 1999, Robert P. Stefko wrote: > >> Jupiter." — Space Travel: A Writer's Guide to the Science of Interplanetary >> and Interstellar Travel > >This sounds like a useful book. Where did you find it? Who's it by, etc? > >Later, > >Eva >@@@(* > *)@@@ > Any bookstore should have it... it's by Ben Bova and Anthony R. Lewis (it's also edited by Bova) it's a writer's digest book and the ISBN is (lemme tear the tag off...) ISBN 0-89879-747-0 and the MSRP is $16.99 (paperback) Sean slugman@itis.com ICQ 24660044 (on the topic of the y2k problem) "How could this be a problem in a country where we have Intel and Microsoft?" --V.P. Al Gore *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message. From: Tun Kai Poh [t_poh@hotmail.com] Sent: Friday, March 05, 1999 9:16 PM To: blue_planet@mpgn.com Subject: [BLUE PLANET] - Blimp madness Yet another website update announcement: In the summer of 1998, I was playing in Dave Klegman's Blue Planet campaign. We were a bunch of GEO investigators operating out of a little settlement in Nowhere. After much underwater submarine jockeying, the wholesale slaughter of an entire underwater GenDiver installation (by us), and some fun with land lizards, we finally uncovered the secret GenDiver plans: experimental genetic engineering using human DNA and various Poseidon species to create the ultimate Supersoldier! It was a grim and solemn moment... "Blimp Hybrids?" I suggested. I thought Dave was just laughing at the time. Heck, I thought I was just laughing at the time. But somehow, the idea never went away. We kept picking at it over the past year. And now, with some input from yours truly, Dave has written up stats for the oddest Genie type ever to appear on Poseidon. It's at for your horrified perusal. Kai "Dances With Blimps" Poh ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message.