I. Euclid Dark Universe Mission, named after Greek Mathematician ‘Euclid’, known as Father of Geometry, is first space based mission dedicated to collect data for understanding Dark Matter and Dark Energy, led by European Space Agency, ESA. Euclid spacecraft will look as far back in time as 10 billion years. In Astronomy, it is known as look back time. A Look back time of about 10 billion years is equivalent to observing objects with redshift close to 2. Weak Gravitational Lensing and parameters related to Galaxy Clustering such as redshift, will be measured to infer insight into nature of Dark Matter and Dark Energy.
II. Euclid will operate for 6.25 years after its launch in last quarter of 2020. During that period, it will cover more than a third of extragalactic space which is equivalent to covering more than 15000 deg2 of sky, excluding Solar System and Milky Way. The spacecraft will also peer about 10 times deeper, for 3 times during its operation, covering 40 deg2 of space for calibration and performance monitoring purposes, during which it will be observing objects with redshift higher than 2, which includes distant Quasars and Galaxies. Euclid will cover about 10 billion objects, measuring weak gravitational lensing of more than 1 billion and redshift of about 50 million of them.
III. Thales Alenia Space, which is Europe’s largest Satellite manufacturer, headquartered in Cannes, France, is chosen to make the Satellite and its service module. Payload Module and telescope, which includes 1.2 m Silicon Carbide primary mirror, Korsch Telescope, covering an area of 0.5 deg2 with a focal length of 24.5 m, will be built by Airbus Defenseand Space. Euclid Consortium which is an International Consortium of Scientists, will make very broad band R+I+Z filter, visible CCD imager- VIS, with pixel size of .1 arcsecond, near infrared, broad band Y,J,H filter Photometer- NISP P and a slitless Spectrograph- NISP S, with common field of view of .53 deg2. Data will be collected by the Spacecraft using these instruments and will be sent to Earth at 855 Gbit/s in 4 hr daily slots in K band (25.5-27 Ghz). Onboard storage capacity will be more than 300 GB. The Spacecraft will have an exposure time of up to 4500 sec/field.
IV. Visible CCD detectors will be a mosaic of 36 (6×6), 4000×4000 pixel each, e2v charge coupled detectors, operating in visible wavelength (550-900 nm). They will be used for measuring shape of Galaxies. Near Infrared detector will be a mosaic of 4×4 Teledyne H2RG detectors, 2000×2000 pixels each, operating in (900-2000) nm wavelengths. It will provide low accuracy redshifts of over a billion galaxies using multicolor photometry and high accuracy redshifts of millions of Galaxies using Spectrometry.
V. Solar Panels will supply power and provide stability to orientation of telescope. Thermal Insulation will be done to protect against radiation heat. The Spacecraft will weigh 2100 kg and it will be 4.5 m long and 3.1 m in diameter. It will be launched to L2 Sun-Earth Lagrangian point- halo orbit using Soyuz ST-2.1B rocket from Kourou launch site, Guiana Space Center. Travel time to orbit is 30 days.
VI. Nasa is collaborating with ESA on Euclid Mission. From JPL Lab in Pasadena, California, NASA will put up infrared flight detectors for Euclid science instrument. Goddard Space Flight Center will be used for testing these detectors. Three US science teams totaling 40 scientists are nominated to add to planning and analysis of data.
VII. Dark Matter is the main contributor to Weak Gravitational Lensing effect of Galaxies as it constitutes most of Galactic matter content. A measurement of bending of light by Galaxies, therefore, gives information about the Dark Matter that it contains. By measuring this effect at this large scale and accuracy, scientists will try to gain additional insight into Physics of Dark Matter. Also, clustering of Galaxies is influenced by Dark Energy. A measurement of clustering is hoped to help in understanding the nature of this mysterious type of Energy.
References:
1) http://sci.esa.int/euclid/
2) https://www.euclid-ec.org/
3) https://arxiv.org/ftp/arxiv/papers/1110/1110.3193.pdf
Image credits goes to respective sources.
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