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The MSSL Space Plasma Physics Group pages have moved to


Information about the PEACE instruments on the Cluster and Double Star Missions remains up-to-date on this site. Please update your links accordingly

text = "#FFFFFF" link = "#B5FF01" alink = "#DA01FF" vlink = "#CC01FF" bgcolor = "#010101"> Polar


The Mission

The Polar spacecraft is one of two NASA spacecraft which contribute to the International Solar Terrestrial Physics Programme (ISTP). The overall goal of the ISTP is to understand the physical mecahnisms controlling the transport of mass, momentum and energy from the solar wind into the earth's magnetosphere.

Launch took place on February 24th, 1996. The orbit is a highly elliptical one with its lowest point at a height of 5100km over the Antarctic and highest point at 51000km over the Arctic. The position of the highest point will move slowly across the North Pole during the first two years of the mission.

The spacecraft carries nine instruments to measure particles, magnetic and electric fields, and three instruments to make pictures in the visible, ultraviolet and X-ray spectrla regions. UK groups participate in two of these investigations.

Science Objectives

Polar's primary objective is to find out how much of the plasma in the Earth's magnetosphere comes from the solar wind and how much is drawn up from the Earth's upper atmosphere. It will take pictures of the aurora over the entire polar cap from high above the Earth. It will measure the particles where they are being accelerated down into the atmosphere to make the aurora.

The TIMAS Instrument

MSSL built a large imaging particle detector for TIMAS (Toroidal Imaging Mass Angle Spectrometer) which measures the mass, energy and direction of positive ions in the energy range from 15eV to 32keV and masses from 1(H+) to 32(O2+)amu. The fast electronic readout allows low-density, rare, ion species to be detected in the presence of dominant species. TIMAS objectives are to look for the entry of plasma into the magnetosphere from the solar wind and to study the outflow of plasma from the atmosphere over the polar caps.

Further Information

The TIMAS Instrument page at Lockheed may be accessed, as well as the NSSDC Polar Page, and the ISTP Polar page.

MSSL Space Plasma Physics

MSSL Home Page

Latest update: February 26th, 1995.

dmw@nojunk-removethis-mssl.ucl.ac.uk static mirrors and a focussing particle collimator system. Within each analyser parallel