Date: Fri, 4 Aug 2000 16:14:58 -0400

To: [Long list]

Dear Colleague:

Although rumors that the Pluto-Kuiper Express (PKE) mission have been
cancelled are not correct, the mission is in serious jeopardy. The
reasons are multiple, including general budget pressure and a sense that
much of the Space Science budget “cannot be touched” to deal with these
pressures. But central to the current weakness of PKE is our lack of a
viable plan for carrying out the Outer Planets Program as currently

We are in this situation largely because spacecraft, launch vehicles, and
power sources all cost much more than were originally budgeted in 1996.
For technical reasons, we were forced to delay the Europa Orbiter (EO)
mission from a 2003 launch to January 2006. But the resulting launch
sequence, PKE in 2004, EO in 2006, and Solar Probe (SP) in 2007 was still
unaffordable. Recently, I and others said that in principle we could
afford a launch sequence which delayed EO and SP each by one additional
year, i.e., PKE in 2004, EO in 2007, and SP in 2008. That turns out to be
incorrect. The original budget, which is the funding still included in
NASA’s current five-year plan, does not support this. EO and/or SP would
therefore have to be delayed even further. Beyond that, in my judgement,
even if the statement about in-principle affordability had been correct,
there would still have been substantial danger that we could not meet the
04/07/08 launch dates because of further cost growth and schedule delays.

To support the Outer Planets Program we must develop a scientifically
compelling, technically and fiscally achievable program plan for outer
solar system exploration as a whole. This plan must include EO and PKE,
as well as the other challenging missions the community and NASA have
identified as high priority. I believe the linchpins for such a plan
include launching EO as soon as we are technically capable and having a
robust technology development program to enable the future missions. Jay
Bergstralh is leading a group of NASA, JPL, and community scientists who
are developing the scientific foundation for this plan. NASA and JPL will
work with the community to complete this plan by the end of this calendar
year. I believe this is essential to get the Outer Planets Program back
onto sound footing.