Wilkinson Microwave Anisotropy Probe (WMAP)

Nov. 18, 2017, 9:44 a.m. By: Kirti


The Wilkinson Microwave Anisotropy Probe (WMAP), that is also originally known as the Microwave Anisotropy Probe (MAP) is named after Dr. David Wilkinson, who is a pioneer in the study of cosmic background radiation and a member of the science team as well. WMAP was a spacecraft that operated from the year 2001 to 2010 and measured temperature differences across the sky in the radiant heat remaining from the Big Bang- cosmic microwave background (CMB).

The mission was developed in a joint partnership between the NASA Goddard Space Flight Center and Princeton University and was headed by Professor Charles L. Bennett. The WMAP spacecraft was launched from Florida on June 30 in the year 2001. The WMAP mission that was the second medium-class (MIDEX) spacecraft in the NASA Explorers program succeeded the COBE space mission. After 9 years of its involvement in operations, WMAP was switched off in the year 2010, following the launch of the more advanced Planck spacecraft by ESA in the year 2009.

"The science goals of the WMAP broadly dictate that the relative Cosmic Microwave Background (CMB) temperature be measured accurately over the full sky with high angular resolution and sensitivity. The need to control systematic errors in the final maps was the overriding priority in the design. The specific goal of WMAP is to map the relative CMB temperature over the full sky with an angular resolution of at least 0.3°, a sensitivity of 20 µK per 0.3° square pixel, with systematic artifacts limited to 5 µK per pixel." According to NASA.

The WMAP was basically preceded by two missions to observe the CMB (i) the Soviet RELIKT-1 that reported the upper-limit measurements of CMB anisotropies, and (ii) the U.S. COBE satellite that first reported large-scale CMB fluctuations.

In order To achieve these goals that had been aimed for, WMAP observes the sky from an orbit of nearly about the L2 Sun-Earth Lagrange point, that is 1.5 million km from Earth and also uses differential microwave radiometers that measure temperature differences between two points on the sky. And since the observatory can always point away from the Sun, Earth, and Moon while maintaining an unobstructed view of deep space, this vantage point proves to offer an exceptionally stable environment for observing. WMAP is said to scan the sky in such a way as to cover ~30% of the sky every single day and as the L2 point follows the Earth around the Sun, WMAP observes the full sky in every six months. Also, WMAP uses five separate frequency bands from 22 to 90 GHz in order to facilitate rejection of foreground signals from our own Galaxy.

When we talk about its structure, Among the main features of the WMAP spacecraft, the most prominent feature is its inclusion of having a pair of back-to-back telescopes that feed it to 10 separate differential receivers that sit in an assembly directly underneath the optics and focus the microwave radiation from two spots on the sky roughly 140° apart.

A few of its features also include: Spacecraft observing at L2 - render, V-band (60 GHz) HEMT amplifier, Microwave instrument - internal, Microwave instrument - external, TRS: Telescope/radiator subsystem, Spacecraft w/ panels stowed, Spacecraft w/panels deployed, WMAP - side view rendering and WMAP - iso view rendering.

The measurements of WMAP played a key role in establishing the current Standard Model of Cosmology: the Lambda-CDM model and the data of WMAP also very well is fit by a universe that is dominated by dark energy in the form of a cosmological constant.

The mission has also won a various number of awards: the Breakthrough of the Year for 2003, according to Science magazine, This mission's results papers in the "Super Hot Papers in Science Since 2003" list were first and second respectively. And only three have been published since 2000, all of the three being publications of WMAP in Of the all-time most referenced papers in physics and astronomy in the INSPIRE-HEP database.

Wilkinson Microwave Anisotropy Probe

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