Robert B From Robert Bennett Mon Jul 2 18:54:38 2007 Robert B From Robert Bennett Sun Jul 1 23:09:46 2007 Also, according to the citations, the Artemis team decided to slow down the satellite by ~200 m/s by firing RITA continuously in the opposite direction of motion for 340 days. Since the velocity is inversely proportional to the square root of the radius from Eq(3), this operation would cause the satellite to rise ~ 5000 km. You can't be serious. Reducing your velocity while in orbit will reduce your altitude not raise it. Unless of course you are basing your statement upon your own private definition of which direction any given satellite is orbiting. Are you so doing? Paul D Yes, occasionally Iʼm serious. The answer to your confusion is in the 2nd sentence. I am not confused. If it had teeth it would bite you. Yes I saw the relationship, however it seems that I understand it better than do you. Let me explain in simple words (since I am not so nimble with maths as are you). A satellite in orbit has energy from its velocity and its mass (mv^2) and it also has energy from its position and its mass (mr). (Yes I know that h1 - h2 complicates it, but the principle still applies). Since the energy due to velocity falls off as r^0.5 and energy due to altitude increases directly as r, it follows that the energy of a satellite in stable orbit increases with altitude. I suggest that you cannot increase energy by subtracting energy eg slowing the satellite by 200 m/s or any other amount. But of course I could be wrong. All you have to do is show the error of my reasoning -- with numbers, since this is easy for you. BTW, can you give me the reference where Artemis state that they slowed the satellite? I wasn't able to find it. For the purposes of demonstration, may I suggest we assume orbit one has a radius of 6500 km where the period will be 86.89 min (92.45 min in the Geostatic (GS) view) and orbit two has a radius of 13600 km where the period will be 245.76 min (296.39 min GS). Challenge - show that a one kilogram satellite in the higher orbit has less energy that the same satellite in the lower orbit. Nevilleʼs Eq(3), derived from Newtonʼs laws, says V^2 = GMe/R, which is an inverse relation between V and R^1/2. (Usually velocity, mass and radius are given in lower case). I apologise here for editing you statement -- it affected the way the Yahoo editor displayed. Obviously it can't handle your very capable editor's output. Guess intuition failed you here, Paul. I think I've demonnstrated that it wasn't intuition. It does seem oxymoronic. Robotmoronic perhaps? BTW: GWW shows that when an object is pushed straight ahead, it actually moves backwards! (OK, now Iʼm not serious) You see, this uncertainty is another good reason for not relying on Gee Whiz Willie. Robert B Paul D ____________________________________________________________________________________ Yahoo!7 Mail has just got even bigger and better with unlimited storage on all webmail accounts. http://au.docs.yahoo.com/mail/unlimitedstorage.html