Sunday, September 20, 2009

Ancient Cosmic Light

Planck started surveying the sky regularly from its vantage point at the second Lagrange point of the Sun-Earth system, L2, on 13 August. The instruments were fine-tuned for optimum performance in the period preceding this date.

ESA's Planck microwave observatory is the first European mission designed to study the Cosmic Microwave Background – the relic radiation from the Big Bang Jessica Gomes Milky Girl

Following launch on 14 May, checkouts of the satellite's subsystems were started in parallel with the cool-down of its instruments' detectors. The detectors are looking for variations in the temperature of the Cosmic Microwave Background that are about a million times smaller than one degree – this is comparable to measuring from Earth the body heat of a rabbit sitting on the Moon. To achieve this, Planck's detectors must be cooled to extremely low temperatures, some of them being very close to absolute zero (–273.15°C, or zero Kelvin, 0K).

With check-outs of the subsystems finished, instrument commissioning, optimisation, and initial calibration was completed by the second week of August.he mission, which is led by the European Space Agency with important participation from NASA, will help answer the most fundamental of questions: How did space itself pop into existence and expand to become the universe we live in today?

The answer is hidden in ancient light, called the cosmic microwave background, which has traveled more than 13 billion years to reach us. Planck will measure tiny variations in this light with the best precision to date.

The mission officially started collecting science data today, Aug. 13, as part of a test period. If all goes as planned, these observations will be the first of 15 or more months of data gathered from two full-sky scans. Science results are expected in about three years.

The European Space Agency missions, with significant participation from NASA, hitched a ride together on an Ariane 5 rocket, but now have different journeys before them. Herschel will explore, with unprecedented clarity, the earliest stages of star and galaxy birth in the universe; it will help answer the question of how our sun and Milky Way galaxy came to be. Planck will look back to Alien in burta the beginning of time itself, gathering new details to help explain how our universe came to be.

"These two missions have spent a lot of time together," said Ulf Israelsson, NASA project manager for both Herschel and Planck at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "But now they are going their separate ways, each ready to do what it does best."

JPL contributed key technology to both missions. NASA team members will play an important role in data analysis and science operations.

Herschel separated from its Ariane 5 rocket 26 minutes after launch, followed by Planck about two minutes later. The spacecraft are traveling on separate trajectories to a point in the Earth-sun system called the second Lagrangian point, four times farther away than the moon's orbit, or an average distance of 1.5 million kilometers (930,000 miles) from Earth. They will spend the rest of their missions independently orbiting this point -- located on the other side of Earth from the sun -- as they make their way around the sun every year.

The 'first light' survey, which began on 13 August, was a two-week period during which Planck surveyed the sky continuously. It was carried out to verify the stability of the instruments and the ability to calibrate them over long periods to the exquisite accuracy needed.