The Current Status of Solar Orbiter
31 May 2006
The Science Programme Committee of ESA met on 15/16 May 2006 and reviewed the status of Solar Orbiter.There is little doubt on the scientific priority of the Solar Orbiter mission, a mission to go inside the orbit of Mercury to get close to the Sun and will climb out of the ecliptic plane to peek at the polar regions.Solar Orbiter was first brought into the programme in 1999/2000 where it was allocated a target budget equivalent to just over 200 million Euro (in present 2006 economic conditions). There was no doubt that this was less than adequate for such an ambitious mission and two routes were proposed for meeting the target; finding an international partner to share the costs and/or to use the efficiencies of scale by building it in parallel with BepiColombo mission to Mercury.
International Partners Have Yet to Emerge
Although the positive history of building Newton/Integral and Rosetta/Mars Express/Venus Express in sequence have saved enormous amounts compared the individual build costs, the extreme test of how far one could go with parallel building represented by Herschel and Planck has shown the limits to the approach.
Using as much as practicable of synergy with BepiColombo but with no assumption on cooperation, the SPC were told that the best financial prediction was currently 410 million Euro. At such a price, the financial headroom foreseen for the programme would not allow a launch before 2017. The Executive had suggested putting Solar Orbiter in competition for the much increased allocation of 410 million Euro for a launch in 2017.
Not only timeliness but also scientific, technical and cost-efficiency advantages accrue from a 2015 launch. In a tour-de-table, it was clear many delegations in the SPC put a priority on doing everything to keep the door open to a 2015 launch.
The 2015 date sets a large challenge at programme level. Against an assumption that there will be no increase in overall programme purchasing power, present estimates of funding availability show that allocating much more than 200 million Euro for such a launch date is going to be very hard.
The chairman of the SPC, Geneviève Debouzy summarised the discussion by proposing to the Executive first to establish the interest in the science community in providing payload by calling for letters of intent from them and in parallel to put in place a 'Tiger Team' to look at the proposed payload, mission plan and cooperation possibilities in order to propose ways in which major cost reductions could be achieved.
The Executive are considering her proposals and starting analysis of how one could meet the massive reductions demanded. In the coming month or so, the Executive will investigate the international cooperation prospects. The mechanisms for interaction with the science community in defining any proposals for cost-cutting and the setting up of any 'Tiger Team' should be announced on the same schedule. The call for letters of intent to provide instrumentation will proceed in parallel.
It is expected that SPC (with advice from the programme advisory structure) will come back to examine the prospects concerning the mission in 2007.