ESA's Planck Observatory Completes High Frequency Observations of Cosmic Background

ESA's Planck Observatory Completes High Frequency Observations of Cosmic Background: The European Space Agency's robust Planck mission ceased operations of the spacecraft's high frequency detector array on Jan. 14, setting the stage for an early 2013 release of mid-mission all sky survey measurements of the cosmic infrared background created by the Big Bang.

Launched in May 2009 with expectations among international science team members for two all-sky surveys, the Planck observatory was propelled to the second Earth-Sun Lagrange point, more than 900,000 miles from Earth. There, the spacecraft's high and low frequency detectors began observations of the cosmic infrared background as well as emissions from cold dust scattered throughout the cosmos.

The European Space Agency's Planck observatory maneuvers toward the second Earth Sun Lagrange point in this artist's illustration. Image credit: ESA

The multiple surveys are expected to furnish new clues about the explosion that created the universe 13.7 billion years ago and the subsequent formation of the earliest stars and galaxies. Planck's high and low frequency instruments completed their fifth all-sky survey at the mission's 30 month mark.

High frequency observations ceased on Jan. 14, as anticipated, when helium coolant for the spacecraft's 52 highest frequency detectors was exhausted, ESA said in a Jan. 16 statement. Low frequency observations will continue into 2012 to gather additional calibration data.

"This gives us even better data than we were expecting from the mission," said Jean-Loup Puget, Université Paris Sud, Orsay, France, principal investigator for the high frequency detection instrument.

Following a preliminary data release next month, ESA plans to publish the wider mission data set in two stages. Observations gathered during the first 15.5 months will appear in early 2013. The full data set is anticipated a year later, according to ESA.

The European mission was developed to build upon findings from NASA's Wilkinson Microwave Anisotropy Probe and Cosmic Background Explorer missions, which examined traces of the radiance from the Big Bang at lower resolution between 2001 and 2010 and 1989 to 1993.

All three missions are focused on the trace left as the universe cooled enough a half million years after the Big Bang for the radiance to emerge. The emissions have been stretched into microwave wave lengths by the expansion of the universe.

So far, Planck mission results have produced a catalogue of early galaxy clusters and measurements of the early infrared background generated by vigorous star forming processes.

The lengthy data release strategy will allow mission scientists to remove foreground emissions contaminating the cosmic background as well as to identify the faintest emission sources from the early universe.