Onwards to Uranus and Neptune! |
Onwards to Uranus and Neptune! |
Jan 12 2008, 09:40 PM
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#101
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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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Aug 17 2009, 05:50 PM
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#102
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Senior Member Group: Members Posts: 1585 Joined: 14-October 05 From: Vermont Member No.: 530 |
That is his point, though, is it not? If huge launchers get 10x cheaper, you design the Neptune Orbiter you want and can also afford the huge detachable propulsion module for NOI for the same launcher price... maybe. And you get there in 10 years rather than 30. Or whatever.
(Isn't aerobraking useless for orbital insertion, anyways? It's for circularization, right?) |
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Aug 19 2009, 10:02 AM
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#103
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
That is his point, though, is it not? If huge launchers get 10x cheaper, you design the Neptune Orbiter you want and can also afford the huge detachable propulsion module for NOI for the same launcher price... maybe. And you get there in 10 years rather than 30. Or whatever. (Isn't aerobraking useless for orbital insertion, anyways? It's for circularization, right?) Yeah, it's always a clue that people didn't read your whole post when they offer supporting arguments as evidence to the contrary. :-) It does leave one hopeful that if SpaceX really does prove itself, we might see a slew of new Outer-planet mission proposals. (Of course, there's still that power-supply problem.) An additional obvious problem with Aerobraking is that (by itself) it only lowers the apapsis, leaving you with a periapsis inside the planet's atmosphere, so you still have to burn fuel (when you do reach apapsis) to raise that high enough to avoid things like atmosphere, rings, radiation belts, etc. Supposedly that's why it's not attractive for planets like Jupiter -- you burn more fuel raising the periapsis than you gained from the aerobraking in the first place. (I haven't worked this out myself though.) In the case of Neptune, in addition to the uncertainty about the atmosphere, I suspect there might also be doubts as to just how high we'd need to raise the orbit in order to be safe. --Greg |
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