STRV Satellites Ready for Launch
Two U.K.-built satellites are about to make history with a long list of world firsts.
The second pair of Space Technology Research Vehicles (STRV-1c & 1d) to be built by the Defence Evaluation and Research Agency (DERA) are scheduled for launch from Kourou, French Guiana, on the evening of 14 November (early morning on 15 November in the UK).
The mission is designed to speed up the introduction of the latest space technology into orbit. Between them, the box-shaped microsatellites will carry 25 different hardware experiments and four software experiments into the harsh space environment of geosynchronous transfer orbit (GTO) 600 x 39,000 km above the Earth.
This highly elliptical orbit exposes the STRV satellites to severe environmental hazards, since the satellites receive very high doses of natural radiation as they pass through the van Allen radiation belts four times a day. Over their one-year lifetime, the STRV satellites will receive radiation doses normally experienced over 8-10 years by spacecraft in low Earth and geosynchronous orbits.
The satellites will also pass through harmful atomic oxygen in the Earths upper atmosphere. By intense exposure to all of these elements, the satellites will allow the testing of new technologies and components to be accelerated.
The satellites carry a suite of environmental monitors, which will give comprehensive radiation measurement, assess atomic oxygen and electrostatic charging effects and detect cosmic dust and ionospheric anomalies. These are sponsored by a wide variety of space organisations in the UK, continental Europe, the USA and Canada.
A number of experiments on STRV-1c will measure high energy particles - protons in the lower van Allen belts and cosmic rays from beyond our Galaxy - that can cause serious damage to spacecraft electronics and solar power generation. Other experiments will study electrostatic charging by electrons in the van Allen belts, which can destroy a satellites electronics.
The radiation experiments include:
- The Cosmic Rays and Dosimetry experiment, provided by the Ministry of Defence and DERA.
- The Surface Charge Experiment (DERA)
- The Standard Radiation Environment Monitor (European Space Agency)
- The Compact Environmental Anomaly Sensor (U.S. Air Force)
- The Proton Monitor (Defence Research Establishment, Canada)
- The Depth Dose Monitor (Defence Research Establishment, Canada)
Other scientific experiments will study different aspects of the hostile space environment:
- Atomic oxygen erodes and corrodes spacecraft components. Southampton University has provided an atomic oxygen experiment on STRV-1c to measure the changing effects of exposure with time and orbital position.
- A micrometeoroid and dust detector provided by the Open University and the European Space Agency will count impacts from natural and man-made particles and distinguish between them.
- A U.S. Air Force / Naval Research Laboratory sponsored experiment on STRV-1d will measure changes in the ionosphere when the satellite is near perigee (its lowest orbital point).
Numerous new technologies covering space communications, remote sensing and navigation will also be evaluated on the STRV-1c and 1d mission.
The spacecraft firsts include:
- Power from an operational, rechargeable lithium ion battery.
- Use of a 'radiation-hard' version of the powerful Sun Sparc microprocessor.
- Use of a novel DERA-patented carbon-composite joint in the spacecraft structure.
- Demonstration of secure communications through data encryption.
- Demonstration of new Internet-based space communications standards that may be suitable for future missions such as a Mars orbiter/lander.
- Comprehensive mapping of the Global Positioning System signal environment at altitudes out to geosynchronous orbit (35,900 km).
- Evaluation of new infra-red detector technology.
'This mission keeps Britain at the forefront of space technology research,' said DERA's Graham Davison, Business Area Manager of Space Department.
DERA designed, built and tested the STRV-1c and 1d satellites in its Space Test Facility at Farnborough, and will operate them from its ground station at West Freugh in Scotland.
The satellites follow the highly successful STRV-1a & 1b mission, which was launched on an Ariane-4 in 1994 and continued to operate for over 4 years.
The launch of STRV-1c and 1d is the first 'piggy-back' launch on an Ariane-5 launcher, in which the microsatellites are placed within the nose-cone, beneath the main satellite. At over 100 kg each, STRV-1c and 1d are twice the mass of the earlier STRV-1a and 1b satellites.
DERAs Space Department has been involved in satellite development since the late 1950s. The Department is currently building subsystems for the European Space Agencys Mars Express and Beagle 2 missions, and leads a consortium to build the TOPSAT tactical optical imaging satellite. DERA also designed and built a medium-wave infra-red camera for the U.S. Department of Defence TSX-5 satellite.
Further information on the STRV-1c and 1d programme is available on the Web at: http://www.dera.gov.uk/