Space Observatory

An ESA Mission
with Participation from NASA

Herschel Status Update

Announcement • June 10, 2009

Herschel is approaching its final orbit around the 2nd Earth-sun Lagrange point (L2), a point in space 1.5 million kilometers (930,000 miles) from Earth on the side away from the sun. As of June 4, Herschel was 1.2 million kilometers (750,000 miles) from Earth and receding at 0.29 kilometers (.18 miles) per second. All three instruments have been powered on successfully, with initial functional tests all positive. About one-third of the in-flight commissioning phase is complete. The commissioning phase will be followed by performance verification, when the instruments and observatory will be characterized in detail. On June 8, decontamination heating of the mirror -- to prevent buildup of any ice on the reflective surface -- will be complete, and the mirror will begin to cool to its operating temperature of about 70 Kelvin (-334 degrees Fahrenheit). The cryostat cover is scheduled to be opened on June 14.