The Grand Tour, A proposal that ended with Voyager 1 & 2 Options

[Guest_Myran_*]

Seeing descriptions and even images of old projects that never did get underway, my memory was stimulated into remember 'The grand tour' plans.

Back in the 1960 the proposal was to fly no less than 4 spacecrafts, each with atmospheric probes for the four gas giants and one even with a flyby of Pluto after swinging past Jupiter and Uranus.

The proposal for this project did fare the same way as many other ambitious plans, that of limited funding but it was skillfuly advocated and eventually ended up with the dual Voyagers (which btw originally only was planned for flyby's of Jupiter and Saturn).

Regardless, if anyone remember some tidbits or even sits on more specific information I would be happy to have my memory refreshed. Thank you in advance!

[Guest_BruceMoomaw_*]

You may be right -- but one of them could certainly have been retargeted to Pluto.

[tedstryk]

You may be right -- but one of them could certainly have been retargeted to Pluto.

The choice had to be made...Send Voyager 1 on to Pluto or have a close Titan flyby. The Titan flyby, thanks to the clouds, was largely a bust, so in 20/20 hindsight, it is a shame it didn't go on to Pluto.

[JRehling]

The choice had to be made...Send Voyager 1 on to Pluto or have a close Titan flyby.  The Titan flyby, thanks to the clouds, was largely a bust, so in 20/20 hindsight, it is a shame it didn't go on to Pluto.

I don't think Voyager 1 @ Titan was a bust. It provided radio occultation data that pegged the surface temperature and pressure so accurately that Huygens scarcely improved the measurement -- THAT is saying something. (I'm sure Huygens shrank the error bars...) That occultation also pegged the mean molecular weight. And Voyager images of Titan in the orange filter DID show surface features, though that fact was recognized only 15 years later.

It is subject to debate if the same information could have been had using later stellar occultations. The key question would be if Cassini/Huygens design was improved in any way owing to the Voyager 1 pass -- could be a PhD thesis to try to shake that out. Extra credit for assessing whether V1's probing of the bow shock would have been altered in the other plan.

Taking the counterfactual too literally, we could say that with Cassini there now, we would have all of the Voyager 1 discoveries in our pocket by today's date anyway, so in a sense, we got nothing from it that we wouldn't have had by 2005, and could only have gained by swapping it for Pluto. Then again, New Horizons would not have been approved if we'd had a Voyager flyby of Pluto, and NH certainly has a superior instrument payload thanks to 28 years of technical improvements. So come 2015, it may be said that *Pluto* science owes a lot to Voyager 1 not having flown by it!