Images released during commissioning of the European Space Agency’s (ESA) recently launched Euclid mission show the spacecraft’s two cameras are in excellent condition to soon begin a six-year mission to learn more about dark energy, dark matter and what the universe is made of.
Euclid was launched aboard a SpaceX Falcon 9 rocket on July 1 and reached its operational orbit at the second Sun-Earth Lagrange point (L2) four weeks later. L2, located about 1 million mi. from Earth, is a gravitationally stable point from which Euclid will observe billions of galaxies dating back more than 10 billion years. The goal of the mission is to produce a detailed, three-dimensional map of the large-scale structure of the universe. The data will be used to shed light on a scientifically vexing period of cosmic history that occurred 5-8 billion years ago when the rate at which the universe was expanding began to accelerate.
The force behind the expansion, referred to as dark energy, comprises about 68% of the universe. Another 27% of the universe is dark matter, which does not emit electromagnetic radiation, with stars, galaxies, planets and other observable matter accounting for just 5% of the universe.
The spacecraft is equipped with a 4-ft.-dia. reflecting telescope that provides data to two science instruments: a 600-megapixel visible wavelength camera known as VIS that takes very sharp images of galaxies over a large fraction of the sky; and the 64-megapixel Near-Infrared Spectrometer and Photometer, which can analyze galaxies’ infrared light by wavelength to accurately establish their distance.
Test images taken by both instruments were released on July 31.
“Ground-based tests do not give you images of galaxies or stellar clusters, but here they all are in this one field,” VIS Instrument Scientist Reiko Nakajima said in a statement.
The Euclid team initially discovered an unexpected pattern of light contaminating the images. The problem was resolved by orienting Euclid to avoid having sunlight enter into what is suspected to be a tiny gap in the spacecraft.
Euclid’s commissioning and performance-verification phase will continue over the next few months.
