NASA will hold a media teleconference at noon today, June 7, to discuss cancellation of the Gravity and Extreme Magnetism Small (GEMS) Explorer mission. It will be streamed at http://www.nasa.gov/newsaudio.

NASA told the National Research Council’s Committee on Astronomy and Astrophysics on Monday that the GEMS mission was “not confirmed” because of significant cost growth in the early phases of mission formulation. NASA programs must pass through certain “gates” before missions are approved to continue and GEMS did not get through one of those gates.

Space News reported yesterday that the GEMS team appealed the decision and was an expecting an answer imminently. GEMS is an x-ray telescope mission in the Small Explorer (SMEX) series designed to measure the polarization of x-rays in the vicinity of black holes and neutron stars. Managed by NASA’s Goddard Space Flight Center, the spacecraft was being built by Orbital Sciences Corporation with a planned launch date in November 2014.

Paul Hertz, director of NASA’s astrophysics division, will discuss the reasons for the GEMS cancellation at the media teleconference today.