^a The survey’s cost appraisals for Wide-Field Infrared Survey Telescope (WFIRST), Laser Interferometer Space Antenna (LISA), and International X-ray Observatory (IXO) are based on the survey’s cost, risk, and technical readiness evaluation (i.e., the cost appraisal and technical evaluation, or CATE, analysis) and project input, in FY2010 dollars for phase A costs onward; cost appraisals for the Explorer augmentation and the medium elements of the space program are committee-generated, based on available community input. The share for the U.S. government is shown in parentheses when it is different from the total. The U.S. share is based on the United States assuming a 50 percent share of costs and includes an allowance for extra costs incurred as a result of partnering.

^b The survey’s appraisal of the schedule to launch is the earliest possible based on CATE analysis and project input.

^c The risk scale used was low, medium low, medium, medium high, and high.

^d Note that the LISA and IXO recommendations are linked—both are dependent on mission decisions by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA).

^e Technical risk assessment of “medium” is contingent on a successful LISA Pathfinder mission.