A NASA review panel endorsed plans to extend the European-led Planck astronomy satellite mission by 15 months and recommended adding funds to the Chandra X-ray Observatory and continuing Spitzer Space Telescope operations for at least one more year.

The U.S. space agency’s Astrophysics Division Senior Review for Operating Missions, which released its findings May 6 after reviewing proposals to extend 11 ongoing missions, also recommended completing the Wide-field Infrared Survey Explorer (WISE) mission in October as currently planned instead of continuing its search for comets, asteroids and stars during a three-month extended phase. While the WISE mission is expected to produce important results, the review panel said there was not adequate scientific justification to continue the mission once the spacecraft depletes its supply of hydrogen used to cool the onboard telescope and detectors.

The unanimous conclusion of the review panel, which meets every two years, was that NASA should continue supporting Planck’s year-old quest for clues on the origin and evolution of the universe by measuring cosmic microwave background radiation. The Planck mission, launched in May 2009, is led by the European Space Agency. NASA provides detectors, cooling hardware and data analysis services.

 The review panel also offered strong support for Chandra, saying that after a decade in orbit the X-ray telescope remains an important tool in understanding dark energy and dark matter. In recent years, Chandra operations have been streamlined to reduce staffing levels. The panel suggested that Chandra operations be automated if that can be done without jeopardizing the spacecraft.

Another of NASA’s Great Observatories, the Spitzer Space Telescope, received an endorsement from the astrophysics panel for a plan to study the size, orbits and atmospheres of exoplanets. Launched in 2003, Spitzer depleted its supply of liquid helium cryogen in May 2009. Without that coolant, two of the observatory’s three instruments no longer function and the third is compromised. Nevertheless, two of the four channels on that third instrument, Spitzer’s Infrared Array Camera, continue to offer excellent image quality, according to the panel.

That camera should be used to study exoplanets identified by NASA’s Kepler Space Telescope as well as objects detected by WISE. The astrophysics review panel said the Spitzer mission should be extended for at least one year, through 2012, and $7 million should be added to the White House’s 2012 funding plan for Spitzer.

The review panel ranked all of the proposed missions from those that offered the greatest to the least scientific value. Those rankings placed Planck, Chandra and Spitzer in the lead, followed by NASA’s Swift satellite, the European Space Agency’s X-ray Multi-Mirror Mission, NASA’s Wilkinson Microwave Anisotropy Probe, the Suzaku orbiting X-ray observatory, NASA’s Galaxy Evolution Explorer, the Rossi X-ray Timing Explorer, the International Gamma Ray Astrophysics Laboratory and WISE.