Onwards to Uranus and Neptune! Options

[SFJCody]

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

[mchan]

Re: JSNK mission. Front this more as a Saturn probe mission with Neptune and KBO flybys as extras. IIRC, the Decadal survey has a Saturn atmosphere probe higher up on the priority list. Make it international with ESA supplying the probe and better yet most of the spacecraft instruments similar to Dawn. Don't see ion propulsion being required. Use Earth flybys to get to Jupiter so a low end EELV like Atlas 401 can be used. Use NH experience with hibernation during cruise to reduce operations costs until the Jupiter flyby. We have enough images from other Earth flybys, so don't even turn on any instruments (except for bring up tests) until Jupiter if that will save a million dollars or more.

[vjkane]

Re: JSNK mission. Front this more as a Saturn probe mission with Neptune and KBO flybys as extras.

Without more information on the trajectory through the Saturn system, it's not known if the Saturn portion allows a probe relay or probe entry with reasonable parameters. One hopes so.

The current Saturn probe proposal involves an equatorial and a polar probe, which requires the relay craft to traverse the Saturn system at high latitudes. The probably would not be possible for a gravity assist to Neptune.

If Neptune is a requirement of the mission, then the Saturn trajectory is fixed. One hopes that it allows a reasonably close pass to Enceladus (see if the geysers are sill operating) and a probe relay.

Then at Neptune, there may be a trade off between a close Triton flyby and probe relay.

In my opinion, getting the elemental compositions of a gas giant and an ice giant would be the primary goals. Then I'd do the best possible at Triton with the understanding that coming close will probably put the spacecraft well out of the elliptic, which may may KBOs harder (I'm not sure what percentage of inner KBOs fall well out of the elliptic).