Venus 73 - A lost opportunity? Options

[gndonald]

I've been browsing through the NTRS and I've stumbled upon a series of reports dealing with an alternative mission plan for the 72/73 Venus launch window (The one used for Mariner 10).

The plan was this:

A modified version of the Mariner 9 probe carrying a 400lb balloon supported atmospheric probe would be launched atop an Atlas-Centaur or Titan IIIc. Upon arrival at Venus the atmosphere probe would be released and the remainder of the craft would either go into orbit or flyby Venus. The RTG powered balloon probe would operate for several months in the upper levels of the Venusian atmosphere.

While I know that Mariner 10 was a great success (albeit with a lot of luck) and the first pictures of Mercury were well worth the effort, I cannot shake the feeling that this plan was a lost opportunity. While the Venusian atmosphere has been studied from orbit and by short term drop probes, only the Soviet Vega probes attempted to carry out 'long term' studies from within the upper atmosphere, though this was limited by the flyby nature of the mission and the fact that the balloon probes were battery powered.

In fact I feel that a good case could be made for such a mission to be attempted in the future, the science payoff would be well worth it.

See:

http://ntrs.nasa.gov/archive/nasa/casi.ntr..._1969006258.pdf

for the 23mb summary report.

This post has been edited by gndonald: Aug 15 2007, 12:53 AM

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[nprev]

Just out of curiosity, JR, do you know what would have been V1's C/A distance to Titan if the Pluto option had been selected? I'm sure that the deep atmosphere would still have been optically evident (albeit probably no occultation opportunites).

Reason I ask is that I mourn for the original Grand Tour... Happy for NH, of course, but that sure would have been cool.

[ugordan]

If I'm not mistaken, Voyager 1 Titan flyby was of big significance because it allowed radio science occultation of the atmosphere, allowing pressure and temperature profiles to be deduced and even the actual physical radius of Titan's surface. Those results would be unavailable if you just saw Titan as an orange ball in the distance and it's questionable how well we would have been able to characterize its atmosphere based only on groundbased stellar occultations. As JRehling pointed out, it was likely this flyby that enabled Huygens to be so successful.

The flyby was very significant in that regard, something that tends to be shadowed by the cameras' inability to pierce through the haze, often leading to assumptions the flyby was a waste.