NASA > GSFC > Astrophysics Science Division > IXO
To: Members of Space Science Advisory Committee, Astronomy Working Group, and Solar System and Exploration Working Group
Date: 15 March, 2011
As you are well aware, 3 "Large" ("L") mission were selected from the Call for Missions issued in 2007 for the first L mission opportunity in ESA´s "Cosmic Vision 2015—2025" plan, for a launch in the early 2020´s. These 3 missions, i.e. EJSM-Laplace, IXO and LISA, are currently nearing the end of the relative Assessment Phases.
All 3 L mission candidates have been proposed to ESA, and have been studied to date, as cooperative enterprises with international partners, with NASA in a key role in all three. As discussed repeatedly with all the Science Programme’s stakeholders, a decision on the future of these missions cannot as a consequence be taken in isolation from the prospective partners.
Recently the US National Research Council has released "decadal" surveys for both astronomy and planetary science. While both surveys recommended continued cooperation with ESA, and ranked highly all three of the L mission concepts under study, none of these was however ranked at first priority.
The US budgetary prospective has now also become known in February 2011, and, given the decadal prioritization, our initial discussions with US counterparts indicate that it has become quite unlikely for any of the three L mission candidates to be implemented as a joint Europe-US mission in the planned early 2020´s timeframe.
We have therefore consulted with both the chairman of Science Programme Committee and the chairman of the Space Science Advisory Committee, and agreed on a way forward for the L missions, which takes these developments into consideration.
Following the completion of the Assessment Phase activities at the end of 2010, and the public presentations of their science cases in February of this year, the plan of activities for the L missions foresaw a decision by the Science Programme Committee on a possible down-selection of the L missions in June 2011. In the light of the new situation, we no longer see the possibility for a programmatically meaningful decision on down-selection of these missions to be taken in the middle of 2011. Therefore we have decided not to propose a down-selection of the L1 missions in June 2011, and have set a new target, in February 2012 for a decision by the Science Programme Committee on the way forward with the L missions.
All three study teams have hitherto been international with equal US and European (and Japanese in the case of IXO) representation, consistent with the proposed cooperative mission framework. We have decided to revise the structure of each L mission study and of the corresponding team in the context of a European framework. Each revised team will be asked to examine if they can restructure their mission concept and its science case to meet a scenario where, in the least optimistic case, a Europe-alone mission could be envisaged. The goal of this activity will be to examine to what extent it will be possible to preserve essential parts of the science goals of each original mission within the framework of an European-led mission with an affordable budget for Europe. The revised missions and their science cases will, in due time, be subject to a new assessment by the ESA Advisory Structure.
We have informed our international partners of this action. We should emphasize that this is not to imply that US or Japanese involvement would not be possible but that it should be understood that the study activities outlined above will be conducted under the assumption of a European-led L1 mission. We shall remain in close contact with JAXA and NASA to ensure the possibility of cooperation if feasible.
Please feel free to circulate this information among all interested colleagues, and feel free to contact us should you wish any additional information on this.
European Space Agency
Head of the Science Planning and Community Coordination Office