SSTL has taken delivery of a Search and Rescue Antenna (SARANT) for use to support the development of the fully operational satellites that will power Europe’s new satellite navigation system.

An important milestone, this is the first payload equipment to be delivered to SSTL since it was selected by the European Space Agency to deliver the navigation payloads for the first 14 satellites in the system just over a year ago. SSTL’s partner OHB-System in Germany is prime contractor, building the satellite bus for these satellites.

As part of a Global navigation satellite systems (GNSS), Europe’s new sat-nav service will provide highly accurate, guaranteed global positioning, including specialised rescue services. Consisting of 30 satellites in 56 degrees inclined circular Medium-Earth-Orbits, the baseline is a constellation with 9 equally spaced satellites (plus one spare) per orbit.

The newly delivered Search & Rescue antenna will be used by SSTL in the full engineering model of the payload.

The Search and Rescue Payload on the satellites will relay distress and co-ordination messages from the COSPAS-SARSAT Search and Rescue service. The diagram below shows a fully operational satellite with the SARANT visible on top.

Continue reading "SSTL receives first payload equipment for European Sat-Nav"

In October 2010 SSTL kicked off a reliability study for the European Space Agency (ESA) in partnership with BAE Systems, looking at alternative approaches to designing and analysing system-level reliability for low cost telecommunications missions.

ARTES-1 is the preparatory element to the Advanced Research in Telecommunications Systems (ARTES) programme. The ARTES-1 programme is fully funded by ESA and enables European and Canadian industry to explore innovative concepts to produce leading-edge satellite communications products and services through research and development activities.

The study will conclude in the first half of 2012 and will propose alternative reliability prediction methods for the design, development and analysis of space systems within the European space industry in general - and low cost telecommunications satellites in particular.

SSTL is developing a new cost effective telecommunications satellite under the name GMP (Geostationary Minisatellite Platform), currently capable of accommodating payloads of up to 32 transponders requiring up to 3kW of power, and being enhanced to accommodate up to 44 transponders / 4.5kW of power. The GMP’s origins lie in the British National Space Centre’s (now superseded by the UK Space Agency) MOSAIC programme. Work completed under MOSAIC (MicrO Satellite Applications In Collaboration) enabled SSTL to develop GIOVE-A for ESA, the first satellite of the European GNSS constellation launched in 2005 and still operational. At an orbital height of over 23,000 km, GIOVE-A also constituted a successful first move “beyond LEO” for the company.

Drawing upon BAE Systems’ experience in system reliability and SSTL’s cost effective design methodologies, the study project team will produce a set of guidelines to evaluate the reliability of low cost design approaches to telecommunications missions of varying size and complexity.

It’s now five years since Space Blog reported on GIOVE-A transmitting its first signals for the European GNSS system. The first validation satellite GIOVE-A, was launched in December 2005 by a Soyuz rocket from Baikonur in Kazakhstan, and is still working well five years after the satellite payload was commanded 'on' from the SSTL Mission Control Centre.

With a design lifetime of 27 months, the five-year-old has exceeded all expectations. Part of its long lifespan can be put down to design margins, though luck comes into it as well, according to GIOVE manager at ESA, Valter Alpe. The satellite has been orbiting through an exceptionally quiet time in the 11-year solar cycle, meaning it has accumulated lower radiation doses than originally anticipated.

GIOVE-A was built by SSTL in just 30 months and carries a prototype rubidium atomic clock designed for the European GNSS constellation. In 2008 GIOVE-A was joined by GIOVE-B, equipped with an ultra-precise passive hydrogen maser design as well as a second rubidium clock. Operational European GNSS satellites will carry both clock designs for maximum reliability.

SSTL’s Optical Payloads Group has commenced a science project that will study fluorescent emissions from vegetation using a remote sensing instrument designed to fly onboard a small satellite.

Carbon dioxide (CO2) is notoriously difficult to measure and so far it has been impossible to calculate the uptake of the Earth’s CO2 sinks with sufficient accuracy for scientific analysis – for example hindering our ability to monitor the efficacy of CO2 mitigation policies. There is an urgent need to improve data on the natural CO2 uptake of vegetation in order to improve our understanding of its influence on the Earth's carbon cycle and its potential to suppress today’s increasing atmospheric CO2 concentration. Even minor changes in ecosystem-scale photosynthesis can have a significant affect on the global carbon balance.

Satellites have made a huge difference to our knowledge of vegetation conditions, but until now most of that information has come from remotely sensing reflected sunlight with multi-spectral Earth observation satellites. There is, however, one additional source of information about vegetation in the optical and near-infrared wavelength range. During photosynthesis part of the energy absorbed by chlorophyll is not used for carbon fixation, but re-emitted at longer wavelengths as fluorescence.

'The European Space Agency (ESA) Fluorescence Explorer (FLEX), which is a candidate for the Earth Explorer 8 missions, aims to provide global maps of vegetation fluorescence that can be converted into an indicator of photosynthetic activity. These data would improve our understanding of how much carbon is stored in plants and their role in the carbon and water cycles.

SSTL will identify one optimised design of an instrument under a 400k€ contract from ESA that will detect the weak radiation emitted in this specific wavelength range from space. The Fluorescence Imaging Spectrometer (FIMAS) instrument will be compact enough to fly on a small satellite as a precursor to the primary instrument onboard FLEX.