The Cassini Spacecraft
EM Receiver being deployed from an
EMGS Electromagnetic Survey
From Saturn To The Sea Bed Exciting Applications For PMES Sensors
PMES provides a wide range of products for the defence, power and rail markets. However, it is its sensor business that has the greatest geographic reach, with high performance sensors currently in position not just around the globe, but also as far out as the rings of Saturn.
An extremely high performance 3-axis Magnetic Sensor developed and manufactured by PMES has been aboard the Cassini Spacecraft since its launch in October 1997. The 900 million mile journey to Saturn took 7 years and the magnetic data is currently being used to describe Saturn's magnetic field and its interaction with Solar Wind and the rings of Saturn. Cassini was back in the news in July 2013 when it sent back the "pale blue dot" pictures of the Earth as it appears from Saturn.
PMES has now received a contract to build the magnetic sensor for the joint ESA - NASA Solar Orbiter Mission. This mission is dedicated to the study of the Sun and its effects on the solar sytem and is part of a programme to answer key scientific questions about the development of planets, the emergence of life, how the Solar System works, and the origins of the Universe. Due for launch in 2017, Solar Orbiter will use a series of Venus encounters to travel closer to the Sun than Mercury, and move to latitudes over 30 degrees to give our first good view of the Sun's poles. Both missions are joint efforts with Imperial College and funded by the UK Space Agency
PMES also manufactures high performance Electric Field Sensors for a wide range of underwater applications. So far the largest application is for the offshore oil and mineral electromagnetic survey market, with over 3000 Sensors supplied by PMES over the past 3 years to the Norwegian exploration company EMGS. These sensors are are installed on the ends of long fibreglass arms on recoverable electromagnetic survey receivers. Up to 150 receivers are deployed at a time from survey vessels; these receivers sit on the sea bed at depths of up to 4000 metres for periods of up to a month.
After deployment, the ship tows a powerful electric dipole source over the sensors, which measure minute secondary fields generated by variations in conductivity beneath the sea bed. After recovery, data processing modelling and inversion are performed to produce 3D resistivity volumes. These datasets are integrated with other subsurface information to enable oil and mineral companies and to make important drilling decisions with a greater level of confidence.
The site also houses the Space Magnetometer Laboratory owned by the Space and Atmospheric Physics Department of Imperial College London. The facilities, which were provided by Ultra Electronics, are used to build and calibrate magnetic field experiments for space missions. Good characterisation of the instruments on the ground before flight is essential for effective in-flight calibration of the instruments in space. The laboratory includes a 3 axis Helmholtz coil facility for characterising the instruments over a temperature range of -50°C to 125°C and a low field, stable temperature test environment for long-term drift measurements.
PMES is actively offering this E Field sensor technology into new markets, which include Geophysical Survey and Corrosion Detection of underwater assets.