Onwards to Uranus and Neptune! |
Onwards to Uranus and Neptune! |
Jan 12 2008, 09:40 PM
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#16
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Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
As soon as MESSENGER gets to Mercury, the most poorly explored planets in the solar system will be Uranus and Neptune. Could this lead to a revival of interest in the ice giants and their retinue, in the same way that the existence of New Horizons is perhaps partly due to the Pluto stamp*?
*via Pluto Fast Flyby and later Pluto Kuiper Express |
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Feb 28 2008, 03:34 AM
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#17
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Well, clearly, JR answered the question in its fundamental form: there ain't no such thing as a free lunch. We can game planetary orbital motion & rotation only so far; sure looks like genuinely revolutionary propulsion systems are needed (very badly) for outer-system exploration.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Feb 29 2008, 02:59 PM
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#18
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Member Group: Members Posts: 613 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
Well, clearly, JR answered the question in its fundamental form: there ain't no such thing as a free lunch. I think there has been some confusion here. 2 very different things 1. gravity assist, as people have mentioned, relates to robbing the planets of their angular momentum (=orbital velocity, since tides are small and the rotational angular momentum of the planets is tiny anyway) The way to visualize this is that the planets are big billiard balls, and you can bounce off them (their gravity fields can be considered the same as an elastic collision). If you bounce off them the right way, you can get a speed boost at their expense, but it relies on them moving fast. 2. more efficient propulsive manoeuvres deep in the gravity well. If your speed relative to the sun is A, and your engine gives you a velocity increment B, the energy increment is (ignoring factors of 2 etc( (A+^2 - A^2, or roughly 2AB. So the bigger A is (i.e. the faster you are going relative to the sun, which is to say, the closer you are to the sun when you make the burn) the more energy increment your fixed B gives you. Not a free lunch, but a way of making your lunch more satisfying. |
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