"Jeff Root" writes:
George Dishman replied to Max Keon:

How hard would it be to send exactly the same Pioneer 10-11
configuration on a trip to Neptune and back?

Several million dollars hard.

The cost of building the spacecraft and the launch
vehicles, launching them, and communicating with them
for about 20 years-- Upwards of 2 billion dollars.
The cost savings of not having to design an entirely
new spacecraft from scratch would probably be balanced
by having to design the new spacecraft to retain the
desired properties of the Pioneers.

From http://saturn.jpl.nasa.gov/faq/mission.cfm
--------
The total cost of the Cassini-Huygens mission is about
$3.26 billion, ...

A better mission to compare to would probably be New Horizons, the
"express" mission to Pluto. The comparison is good because one would
probably want a Pioneer-like mission to the outer solar system where
the cruise phase was shorter than the average person's career.
Wikipedia quotes a cost of $650M for New Horizons.

The Pioneers were funded by US federal taxes. Since
this new project is above and beyond anything that NASA
has funding for or could get funding for, it would have
to be funded privately. ...

NASA does have opportunities for new missions which are heavily
competed for, but those opportunities have ... er... decreased
significantly in frequency in the past few years.

One problem with a "new gravity" mission is that one would want a very
simple mission with few instruments and physical structures, in order
to avoid systematics like solar radiation pressure effects. On the
other hand, even simple deep space missions are very expensive (launch
services alone would be at least $150M, plus a deep space mission
can't rely on solar power), so NASA would want a lot of "bang for the
buck." It would be a delicate balancing act to get a simple "new
gravity" mission more highly ranked than other mission proposals with
well-stocked science portfolios.


... Since I suspect that the Deep
Space Network is already stretched to the limit, at
least one new 70-meter-class communications dish would
need to be built. That might actually be an incentive
to do the project. Each dish would probably cost from
50 to 100 million dollars to build, and could be for
other missions during the same time period that they
would be supporting the new project, and after.

I suspect that by the time a new mission would be ready for launch,
the subscription rate to DSN may be lower, but that really depends on
the actual spacecraft traffic to Mars.

Craig