The observer

One of the most important jobs for the myriad satellites orbiting the Earth is to look back at the planet and send data on the ever-changing conditions below. From watching the swirl of weather systems to monitoring the flows of warm and cold water in the oceans, space-borne instruments offer some of the best ways of understanding the connections between atmosphere and climate, and how changing levels of gases and other substances in the atmosphere can influence climate change.

The UK is one of the world’s centres for space-borne instrumentation, influenced by the long history of astronomical research dating back to Isaac Newton, Edmund Halley and Robert Hooke. But this technology develops fast. To keep abreast of the challenges, and ensure the UK keeps its leading position, the Natural Environment Research Council (NERC) and DTI have set up a Centre for Earth Observation Instrumentation (CEOI).

Headed by Mick Johnson, director of mission systems at EADS Astrium in Stevenage, the CEOI is a collaboration among Astrium, Qinetiq, Leicester University and the Rutherford Appleton Laboratory, part of the Science and Technology Facilities Council.

‘This is something the NERC has been trying to put together for a couple of years,’ said Johnson, ‘and we in the industry put together the team.’

Johnson’s entire career has been concerned with instrumentation. After graduating from Oxford with a general engineering degree, he started work at the testing and certification organisation SIRA, evaluating process instrumentation. From there, he moved to the electronics development side of the business, working on instrumentation for on-line monitoring incorporating sensitive photo detectors.

After a spell in heavy industry at Babcock, developing control systems for power stations, Johnson took his first step into space science at one of the world’s most venerable space institutions, the Royal Greenwich Observatory (RGO).

‘I was working on scientific instruments, controls and software for scientific instruments, including spectrographs and imaging systems for the very big telescopes at La Palma in the Canary Islands,’ he said.

‘It felt like a very natural next step to work on these sort of scientific instruments, rather than industrial ones. It was sort of a big step, but it followed on from my industrial experience in microprocessor development, and it was taking these same kinds of technologies to control instruments for scientific purposes, rather than industrial ones.’

Johnson spent 15 years at the RGO, eventually taking responsibility for the overall instrumentation development programme for La Palma. ‘It was a project management role, really,’ he explained. ‘It took in everything from funding to placing contracts and overseeing the whole programme, reporting to an international steering committee.’

This stood him in good stead for his move to Astrium, where he has worked since 1998. ‘The mission systems group essentially looks at future missions and future technologies, mostly for the European Space Agency,’ he said.

It’s a co-ordinating role, often concerned with carrying out feasibility studies at various levels of detail for all types of instrumented space missions. ‘As well as Earth observation, my group has been looking at big astronomy missions, including missions to Mars and studies of near-Earth asteroids.’

Again, Johnson said, the move from the RGO was a natural progression. ‘I’ve always been interested in space,’ he said, ‘and when I was at the RGO, although we were working on ground-based telescopes, there was obviously a link to astronomy. I spent a lot of time talking to astronomers and understanding their requirements, so we could produce the right instruments for their purposes.

‘Astronomers are just as interested in data that comes from satellites as from telescopes, so there was a good synergy between the sort of work I was doing there and what I’m doing now.’

One project evaluated by Jackson was the European contribution to the Global Precipitation Mission, intended as a constellation of about eight satellites from various national space agencies, equipped with radar systems that could detect rainfall. ‘One of the aspects of it was to look for very heavy rainfall. You could then tie that data up with the geography in particular areas, such as those that are known to be prone to flash floods, and issue a warning to those areas. And this could be done in real time — when the satellite flies over Europe, for example, it could spot heavy rainfall within five minutes, send that data to a ground-station and issue a flood warning within 20 minutes of the rain starting, well before it made it from the high ground to the areas where villages are.’

Unfortunately, EGPM was not funded, although NASA and the Japanese space agency are believed to be going ahead with their contributions to the project, with launches pencilled in for about 2015. ‘It’s still on the books as a future mission, though. I suspect at some time Europe will join and we’ll fund a satellite.’

Earth observation is an integral part of Astrium’s work, however, and the CEOI is an attempt to bring together the UK’s expertise in the area.

‘There’s a lot of capability, in universities, places like the Rutherford-Appleton Laboratory and in industry, but it’s not always easy to get these people to work together,’ said Johnson. ‘So the CEOI is trying to encourage teams to get together and develop technologies, and to encourage knowledge exchange between academia and industry in both directions.’

The goal is to boost the UK’s capability to bid to place instruments on Earth observation missions. ‘There could be opportunities anywhere in the world that wants these sorts of instruments,’ Johnson said. ‘Obviously ESA is a good way for these missions to be funded, but equally we could pitch to NASA or any other agency.’

The purpose of Earth observation missions is mainly environmental, said Johnson, and is often concerned with studying climate change.

‘There are some very definite gaps in our knowledge,’ he said. ‘For example, it’s very difficult to measure carbon dioxide levels accurately from space, and there are currently no dedicated CO_²measurement missions in orbit. You can measure it, but you need accuracies of better than one per cent if you want to verify that particular nations were meeting the emissions obligations they’d signed up to, for example. One of the things we’re working on is the optics for a Lidar (light detection and ranging) instrument which can measure CO₂ concentration.’

The CEOI is also working on instruments to measure other pollutant gases in the atmosphere via geostationary satellites. ‘We’ll measure in the UV and optical spectra with a passive sensor, so effectively we’ll just be looking at reflected sunlight, observing the absorption of particular light wavelengths. That means we can understand the concentrations of various gases such as oxides of nitrogen. And because we’re looking at geosynchronous data, we can look at Europe, say, continuously, and give frequent updates on pollution in the lower troposphere, which equates to air quality.’

Another mission might include sensors to detect very small levels of trace gases, to study their effect on climate.

‘We’ll be using the microwave spectrum for this, which allows us to detect a lot of trace gases. But the signals are extremely small, so we need quite sensitive detectors, and also the wavebands we need to look at are very narrow, so we need good filtering techniques in the microwaves.’

Johnson is confident that the CEOI can foster the sort of cooperation it needs, and is bullish about promoting the space industry’s importance to the UK. ‘More than 17,000 people are employed in the industry, and the productivity, in terms of value per worker, is £135,000, which is very high. It’s four times the national average. We almost inevitably have to concentrate on things we’re good at and develop those skills.’