1. Harvey Tananbaum Director Chandra X-ray Center Harvard-Smithsonian Center for Astrophysics 13th HEAD Meeting April 8, 2013 Building International Space Observatories Building International Space Observatories

2. Long History of International Collaborations on X-ray (High Energy) Missions

3. Currently Operating X-ray (High Energy) Missions with International Collaboration Chandra Discovered separation of dark/normal matter in clusters Map of matter/antimatter annihilation (e+-) in Galaxy INTEGRAL Discovery of relativistic Fe L lines, verification of relativistic K lines in AGN XMM-Newton First view of gas falling into galaxy clusters Suzaku Discovery of most distant galaxy to date at z=8.29 Swift Discovery of g-ray pulsarsFermi

4. Chandra X-ray Observatory

5. Chandra Observing Time Cycles 11-14 allocated 86.3 Ms of General Observer Time: over-subscription avg 5.1 Average of 555 GO observing proposals per cycle: 174 or 31% with non-US PI Comparable success rate with at least some observing time approved: 33% for proposals with US and 30% with non-US PI GO time: 80% to US and 20% to non-US PIs Proposal success rates and over-subscription on time consistent with shorter proposals having higher success rates and non-US PI submitting higher fraction of shorter proposals

6. Two Primary Approaches to International Collaborations Independent of approach seem to have general agreement that bulk of observing time should be open to scientists world-wide with selection via Peer Review to optimize science return 1.Contribution of an instrument (in part or totally) by one Agency to a mission led by another (model for most of experience in High Energy Astrophysics to date) 2.Substantial participation by 2 or more Agencies in designing and building an Observatory with close to equal partnerships (model for International X-ray Observatory – IXO)

7. International X-ray Observatory Observatory scope (and cost) requires full integration of international partners, at sub- system & mission level Major increase in effective area with high spectral resolution for both point and diffuse sources. Great Observatory — time allocation done as with Hubble, Chandra, Spitzer Launch NET 2021, via EELV or Ariane 5 to L2 Merger of ESA/JAXA XEUS and NASA’s Constellation-X missions

8. Modular Design Provides Well-Defined Responsibilities and Interfaces

9. IXO International Consortium The IXO project is already well integrated as an International team! International structure in place since Spring 2008; Instrument Working Group, Telescope Working Group, Science Definition Team, Science Co-ordination Group have International membership This International structure will form the basis for an integrated International project as the mission enters into development Either NASA or ESA will lead the mission, to be decided by NASA, ESA, and JAXA in Phase A IXO Team Meeting 9/2008 MPE Garching, Germany

10. New Worlds, New Horizons – 2010 Decadal Survey IXO ranked very high based on scientific capabilities and importance of (potential) discoveries IXO ranked 4th among large-scale space missions Technical risk medium-high: - manufacture of large aperture mirror with 5" resolution - uncertainty in total mass & low margins might require more expensive LV - secondary instrument components technically immature (TRL 3/4) CATE estimate $5B for 50:50 partnership: NASA cost $3.1B based on 25% "foreign participation” penalty assessed for 50:50 joint program (p19 & 257)

11. New Worlds, New Horizons – 2010 Decadal Survey Key decision points before mission start: - down-select between 2 mirror technologies - ESA selection for next L-class mission - insure that principal risks are retired Conclusions re Partnerships (p94 NWNH): - complex and high-cost facilities essential - typically involve collaborations of multiple nations and/or institutions - bring opportunities for pooling resources and expertise - present management challenges - require new level of strategic planning

12. Post Decadal IXO-Related Actions NASA team supports ESA-led studies for Cosmic Visions (2010 - 2011) NASA team develops down-sized AXSIO concept based on NWNH (2010 - 2011) Based on NWNH plus NASA budgets, ESA initiates European version of scaled back IXO (and LISA) --> ATHENA studies (2011 - ). NASA charters Community Science Team to develop concepts for lower cost approaches to address high priority IXO science (2011 - 2012) ESA selects JUICE as next L-class mission (2012) SAO-led team initiates technology development for adjustable optics for SMART-X mission (2010 - ). Chandra-like angular resolution, with IXO-like area for 2020 Decadal and launch by 2030

13. Further Thoughts Stay tuned for upcoming panel discussion