A UK-assembled satellite is set to go into orbit shortly to monitor air quality around the globe.
Its Dutch-designed instrument will make daily maps of polluting gases and particles known to be harmful to health.
S5P will ride to orbit on a converted Russian intercontinental ballistic missile called a Rockot.
Lift-off from the Plesetsk Cosmodrome is scheduled for 12:27 local time (10:27 BST; 09:27 GMT).
Controllers will know they have a functioning satellite in position above the planet about an hour-and-a-half later when they first receive a radio communication from S5P.
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The EU, with the help of the European Space Agency (Esa), is developing a constellation of satellites as part of its Copernicus programme.
Five of the platforms are already up; many more will follow in the next few years.
All called Sentinels, they are tasked with taking the pulse of the planet and gathering data that can inform the policies of member states – everything from fisheries management to urban planning.
The Sentinels, in number and capability, dwarf anything planned elsewhere in the world, and Sentinel-5 Precursor, to give it its full title, is one of the big UK contributions to the whole endeavour.
The satellite’s TROPOMI instrument has been developed by a consortium led from the Netherlands’ national meteorological agency (KNMI), and will build daily global maps of key gases that contribute to pollution.
These include nitrogen dioxide, ozone, formaldehyde, sulphur dioxide, methane and carbon monoxide. All affect the air we breathe and therefore our health, and a number of them also play a role in climate change.
The “Precursor” in the spacecraft’s name references the fact that the TROPOMI instrument comes before a near-identical sensor that will eventually fly on Europe’s next-generation weather satellites from 2021.
Putting up 5P now also ensures there is no data gap in observations should an ageing, previous-generation instrument suddenly fail. That sensor, called OMI, flies on the US space agency’s Aura satellite.
Although still in good health, it is operating far beyond its design lifetime. But TROPOMI is more than just a gap-filler, says KNMI’s principal investigator Pepijn Veefkind because it is a step on in performance with a tenfold improvement in resolution on what has gone before.
“Big sources, such as power plants – you will be able to detect them. But generally we will be on the city scale. So for example in the Netherlands, we will be able to distinguish between the centre of Rotterdam and the harbour,” he told BBC News.
One major use for the data will be in delivering air quality forecasts, including providing warnings when citizens are likely to encounter problems like smog or high UV (ultraviolet light) levels.
British atmospheric scientist Paul Palmer said some of TROPOMI’s climate observations would be just as important, and highlighted its detection of the greenhouse gas methane.
“It’s kind of the poorer cousin of carbon dioxide, but it has a fascinating story of its own,” the Edinburgh University researcher explained.
“In the 1990s its growth rate in the atmosphere went to zero for seven years before then going back up – and we don’t know why. The quality of the data has not been sufficient for us to say why that happened; and that’s a big problem.
“Having the daily information from TROPOMI, I’m hopeful that if something similar happens again we’ll be in a better position to explain what’s going on.”
S5P was built in Stevenage, north of London, by Airbus Defence and Space UK, under a 45.5m euros (£40m) contract signed in 2011.
British industry has provided components for other Sentinels already in orbit, but Precursor is the first platform whose construction has been led from the UK.
What is the Copernicus programme?
- EU project that is being procured with European Space Agency help
- Pulls together all Earth-monitoring data, from space and the ground
- Will use a range of spacecraft – some already up there, others yet to fly
- Expected to be invaluable to scientists studying climate change
- Important for disaster response – earthquakes, floods, fires etc
- Data will also help design and enforce EU policies: fishing quotas etc
And although Copernicus and its Sentinels are an EU initiative, UK ministers have made it clear they do not want to leave the programme when the country quits the European Union in March 2019.
The recent Brexit position paper on science (PDF) stated that the UK wished to continue involvement in Brussels’ space programmes.
UK Space Agency Chief Executive, Graham Turnock, said the Copernicus programme had been a fantastic success story for the UK.
“It has a global vision and provides near real-time measurements of Earth on an unprecedented scale – and we’ve been a key part of it.
“It’s been a major work programme for UK space technology companies, but data from the Sentinel satellites is why Copernicus exists – data that benefits the UK in areas such as emergency response, flooding, farming, environmental management, rural payments, air quality, marine planning, (and) fisheries.”
Prime Minister Theresa May was committed to collaboration with European partners on science and technology, he added.
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UK-built Sentinel satellite to track air pollution