SSTO:   Solar Probe Workshop ParticipantsFROM:  SS/Director, Space Physics DivisionSUBJECT:     Update on Solar ProbeFire and Ice.  The Solar Probe mission has been given Òa new lease on lifeÓ with  the ÒFire and IceÓ concept for a U.S.-Russian cooperative program to conduct  close flybys of both the Sun and the Pluto-Charon system.  The name Fire and Ice  reflects the fact that this joint program refers to exploration of both the hot  inner- and cold outer-regions of our Solar System.  This name has, of course, been  used in the past.  However, the program now being considered is unique in at least  two ways:  (1) it is truly a joint program between Russia and the U.S.; and (2) it is  based on synergism of the Pluto Flyby and Solar Probe spacecraft.    Technical Team.  It seems unlikely that either the U.S. or Russia alone would  carry out either the Pluto Flyby or the Solar Probe mission in the near term,  whereas together they have a reasonable chance of starting both missions before  this decade is over and completing them well before the end of the next decade.  A  Fire and Ice Technical Team has been established jointly by NASA and the Russian  Space Agency (RKA) under the chairmanship of Charles Elachi of JPL and Alex  Galeev of the Russian Academy of Science (RAS) Space Research Institute (IKI).   This ad-hoc team is responsible for Òstudying and defining this program,  focusing on the commonalty in the spacecraft design and subsystems for the Pluto  Flyby and the Solar Probe missions.Ó  Solar Probe is, therefore, the greatest  benefactor of this approach, because it can benefit greatly from the detailed Pluto  Flyby study that has been underway for about two years.  Our (Solar Probe)  challenge is indeed to catch up with Pluto Flyby!   Joint Science Steering Group.  The U.S.-Russian agreement that established  the Fire and Ice Technical Team (copy enclosed) also established a study team for  ÒMars Together,Ó and it reconfirmed continued cooperation in the Spectrum  series of astrophysical investigations.  All of these activities are under the  auspices of the Joint Working Groups (JWG), which were created to implement  the 1987 cooperative space agreement between our two countries:  the Solar-Terrestrial JWG is responsible for Solar Probe, whereas the Planetary JWG has  responsibility for the Pluto Flyby.  The enclosed chart outlines the tentative Fire  and Ice management scheme, with the focus on the Galeev-Elachi Technical  Team.  In order to coalesce the likely different goals and objectives of the  science communities, in the U.S. and/or in Russia, it was decided at the most  recent JWG meeting, May 3-6, 1994, to establish a Joint Science Steering Group  (JSSG).  This JSSG, which serves as the interface between the Science Working  Teams (SWT) in the two countries and the Fire and Ice Technical Team, includes  key programmatic and scientific personnel from each country:  G. Withbroe,  V. Jones, T. Holzer, B. Feldman, and B. Tsurutani from the U.S. and A. Galeev,  V. Oraevsky, O. Vaisberg, I. Zhitnik, and M. Panasyuk from Russia.  An e-mail  network has been established among the members of this group to facilitate its  deliberations.Technical Team Study Schedule.  The technical study is on an extremely fast  track, because the TeamÕs output is needed for preparation of the FY 1996 NASA  budget request, which will be submitted to the Office of Management and Budget  (OMB) later this year.  Since its creation in April, the Technical Team has been  working closely with JPL personnel in the U.S. and with Lavochkin NPO/Babakin  personnel in Russia to define the Pluto Flyby and Solar Probe missions.  The Team  held a U.S.-Russia video conference on May 10, 1994, and its first full meeting will  occur the week of June 6, 1994, at JPL.  The second Team meeting will be in July,  possibly in conjunction with the COSPAR meeting in Hamburg.  A mid-study  report will be made to NASA and RKA in mid-August, and a final meeting is  tentatively scheduled for mid-October in Moscow.  Following the mid-August  meeting, the Technical Team hopes to present a very limited set of options to RKA  and NASA Headquarters and then, following feedback on those options, focus the  remaining study on the most promising one(s).  A final report on the Fire and Ice  definition study should be presented to NASA and RKA by about mid-November.    Solar Probe Workshop.  Past meetings of the U.S. Solar Probe Science Working  Team under the chairmanship of Bill Feldman, with Bruce Tsurutani as Study  Scientist, have led to a well-defined set of objectives and instruments related to  in-situ particles and fields measurements.  A lot of interest has also been  expressed in imaging, but the mission constraints (cost, mass, power, telemetry,  etc.) have generally been perceived as too limiting to accommodate sophisticated  imaging instruments.  Now, however, the rapidly-changing technological  improvements, coupled with the possibility of a very capable Proton launcher  from our Russian partners, may have opened up a new world of opportunities for  Solar Probe.  The workshop being hosted by Tom Holzer June 28-30, 1994, at the  High Altitude Observatory (HAO) will specifically address these opportunities,  with the goal of defining the critical science for a near-Sun mission with our  Russian partners, within the still-severe budget constraints.  The JSSG is also  considering other programmatic constraints, e.g., launch vehicles, which could  impact the deliberations of the workshop.  Until now the Technical Team has been  given information about the Small Solar Probe in-situ objectives and instrument  set that came out of the last Solar Probe meeting held at JPL in April 1993, with the  promise of an update soon after the June 28-30, 1994, Solar Probe Workshop.    Workshop Input to the Technical Team.  The Russian side has been  developing its Solar Probe mission objectives more-or-less in parallel with the  U.S.  We know from past JWG meetings that the two sides have many similar goals,  but that some differences in emphasis do exist, as they do within different parts of  the scientific communities in both countries.  The HAO workshop findings will be  reported as the U.S. science community input into the JSSG, which will have the  task of convoluting those findings with the science input from the Russian  scientists and the programmatic constraints of both countries.  The JSSG members  will meet and/or exchange their views on the workshop by e-mail, etc., in the  interim between the June 28-30, 1994, workshop and the mid-July meeting of the  Technical Team.  Hopefully, a consensus will be quickly reached that can be  passed on to the Technical Team for its timely perusal in defining the Fire and Ice  mission.   I want to thank you, the participants in the Solar Probe Workshop, for taking  some of your precious time to help us define the critical science for mankindÕs  first reconnaissance mission of exploration and discovery to the center of our  solar system.  I believe this mission is worthy of a major joint endeavor of our two  great space-faring nations, Russia and the U.S.  I also take personal pleasure from  the fact that the Fire and Ice approach gives us the opportunity to work in  concert with our sibling division, the Solar System Exploration Division, which  has played such a fundamental role in supporting Space Physics Division science  activities as it explored the planets.       George L. Withbroe