Super Satellite

Satellite technology provides us with many advantages, chief among which are climate and environmental concerns, and locational services.

Here, we take a look at some of the top projects of the day relating to these major concerns.

Meteosat’s next generation

Meteorology has played a big part in the satellite story from its earliest days. Climate monitoring from space effectively began back in October 1959 with Nasa’s Explorer 7, and given the current crop of projects in the sector, the appeal of orbital observation clearly remains as strong as ever.

In February, the final go-ahead was given for the European Space Agency’s (ESA) next range of geostationary weather satellites – the €3.4bn Meteosat third generation (MTG), which is intended to provide high-resolution meteorological data to 2037. Described by Dr Lars Prahm, director general of Eumetsat, the international agency responsible for overseeing the project, as “a vital programme that will assure the future of Eumetsat’s geostationary observations over Europe, Africa and the Atlantic Ocean over the next few decades”, it is one of the largest and most complex space projects ever to be undertaken by Europe.

Although this new fleet obviously follows on from the existing, and highly successful, Meteosat constellation, it represents a significant step change in technology, and will provide higher resolution imaging, faster transmission to ground and greater forecasting accuracy. The complete series consists of a total of six spacecraft of two types – four imaging satellites (MTG-I) and two sounding satellites (MTG-S).

Featuring an infrared instrument first pioneered aboard the MetOp polar-orbiting Earth-observation platform, this sounding element is a key project innovation that will allow Meteosat satellites to analyse the atmosphere on a layer-by-layer basis for the first time. In addition, over its lifetime, MTG is also expected to deliver significant enhancements to numerical weather prediction and ‘now-casting’ of severe weather conditions, and improve the monitoring of aerosols, particulates and overall air quality.

The consortium that is to build them is now agreed (Thales Alenia Space, OHB-System, Kayser Threde and Astrium), and the first MTG-I spacecraft is expected to be operational in late 2017, with the first MTG-S following early in 2019.

Aquarius and the environment

Climate monitoring also features prominently in Nasa’s planned launches, with the likes of the Aquarius and global precipitation measurement (GPM) missions scheduled for 9 June 2011, 2013 and 2014, respectively.

Aquarius / SAC-D is a collaboration of Nasa and Argentina’s Comisión Nacional de Actividades Espaciales (CONAE), with additional participation from Brazil, Canada, France and Italy. Able to detect salt concentrations with an accuracy of 0.2 practical salinity units (psu) – said to be the equivalent of finding a pinch of salt in a gallon of water – the satellite will pioneer the mapping of global changes in ocean-surface salinity, a phenomenon which is at present imperfectly understood. As the project’s principal investigator, Gary Lagerloef explains, “very small changes in salinity can have large-scale effects on ocean circulation and the way the ocean moderates our climate. These changes are linked to the movement of water between the ocean, atmosphere and cryosphere.” Aquarius’s three-year mission could go a long way towards extending our knowledge of the world’s water cycle and help make future climate models increasingly reliable and robust.

Biospheric scientist and astronaut Piers Sellers said, “you need a global view to understand global processes,” and there is arguably no better proof of that than when it comes to quantifying the distribution and intensity of rain across the entire planet – the task of the multiple spacecraft GPM mission. A core craft, equipped with conically scanning radiometer and dual-frequency cross-track scanning radar, will measure precipitation structure and provide the calibration standard for the other low-inclination spacecraft which make up the constellation. The scope of the project is undeniably ambitious, but if it all goes to plan, it is one which will undoubtedly advance our understanding of the unique global role precipitation plays in climate.

Positioning, navigation and timing

Satellite navigation may have a shorter history that weather-watching from space, but already global navigation satellite systems (GNSS) have assumed a pivotal role in 21st-century life, their precise positioning, navigation and timing (PNT) functions having made them indispensible core components of the global economy. With users as disparate as the defence, transport, logistics, communications, banking and agricultural industries, January’s European Commission mid-term review of its Galileo satellite navigation programme concluded that, “already, 6%-7% of GDP in Western countries, i.e. €800bn in the EU, is dependent on satellite radio navigation.” It is, then, no surprise that the current satellite boom also encompasses the world’s GNSS programmes.

The first batch of Galileo spacecraft – a total of four in-orbit validation (IOV) satellites – are scheduled to be launched over the next two years, with the addition of a further 14 full operational capability (FOC) craft bringing the system to its first operational configuration of 18 craft in medium Earth orbit by 2015. However, with infrastructure costs through to 2020 recently estimated at €5.3bn, Europe’s straitened financial environment has undeniably put a kink in the original plans for a 30-strong constellation, and at least for the time being, no further funding has been committed to increase the numbers.

GNSS upgrades

Even as the new entrant from Europe gradually begins to take shape, upgrades and enhancements are underway for the sat-nav systems that are already in the game – the US’s familiar and well-established GPS, the Russian GLONASS and Chinese Compass / Beidou-2.

GPS attained full operational capacity in 1995, but advances in technology coupled with the growing demands placed on the system have effectively mandated a programme of modernisation, which continues with the deployment of the GPS IIF, and then ultimately, GPS IIIA blocks of satellites. The first of these, the GPS IIF-1, has been operational since August 2010; it is scheduled to be joined by another in June. Ten more IIF spacecraft are to follow over the next few years, with the inaugural GPS IIIA satellite launch currently planned for 2014. Once completed, the upgrades are expected to double system accuracy, allowing locations to be estimated to within less than a metre.

February saw the launch of the first GLONASS-K; this latest-generation spacecraft is much improved, having a longer life-span and substantially better accuracy than any of its predecessors. It is also the first of its kind to be unpressurised, which substantially reduces its weight. The second and third K Class satellites are currently under development, with target dates of 2013 and 2015. Similar moves are afoot in China too, with the launch in April of the eighth of the Compass navigation satellites; a further two are planned by 2012, and the remainder of the constellation – comprising five satellites in geostationary orbit and 30 in medium Earth orbit – is expected to be in place by 2020.

With so much activity, and by so many international players, it really is small wonder that – as the Washington Post once put it – it’s getting crowded up there.