Exploration of the solar system features regularly in the news. Recent achievements include a ‘rendez-vous’ between European Space Agency (ESA) probe Rosetta and the comet 67P/Churyumov-Gerasimenko, while its lander, Philae, successfully made it to the comet’s surface. On Mars, NASA probes have found new evidence for free-flowing water and living organisms in the planet’s past, and spotted the UK’s long-lost Beagle-2 probe on the surface. Meanwhile, further exploratory missions – NASA’s Dawn and New Horizon probes – promise to send even more new discoveries from the dwarf planets Ceres and Pluto in the first half of 2015.
Such exploratory probes need highly sensitive sensors to gather data for scientists on Earth. The EU-funded TeraComp project has developed a new ‘terahertz receiver’ that could help to detect traces of life in space – especially if used for the first ESA mission to Jupiter’s moons, planned for launch in 2022.
“If Europe is going to send instruments into space, we need to be able to produce some of the key technologies in Europe,” says Jan Stake, project leader at the Chalmers University of Technology, Gothenburg, Sweden. “Building the capacity to make these instruments benefits European industry,” he explains, reducing reliance on US suppliers.
State-of-the-art space science
“We have developed a state-of-the-art receiver operating at 557gigahertz for molecular spectroscopy in space science applications,” Stake continues.
“We’re talking about wavelengths smaller than one millimetre or ‘sub-millimetre waves’,” he explains, at frequencies between microwaves and infra-red. “Many molecules have absorption spectra in this range – such as water, oxygen, carbon dioxide – the substances astronomers and planetary researchers are looking for.”
The project team focused on developing Schottky diodes – devices to detect and receive high-frequency signals. “It’s an old technology but it’s difficult to make it work at this very short wavelength,” says Stake.
The team also worked to integrate complementary circuits such as a local oscillator within the same receiver. This enabled them to push the frequency response as high as possible and optimise the components so that they work well together. “We start with microwave circuits and then multiply up the frequency until we generate a signal for the receiver and signal processing,” explains Stake.
Advancing knowledge of the planets
The end result is a compact, lightweight receiver – “state of the art, with good performance at the water-frequency range” – that could make the grade for ESA’s upcoming JUICE mission to Jupiter’s moons. The instrument can also be used in weather satellites, such as the forthcoming METOP, which measures the water content in the atmosphere for weather forecasts and for monitoring pollution and global warming. In this way, the project’s work will help push forward scientific knowledge about our own planet, and others.
“Beyond atmospheric science and planetary missions, we also have ideas for ground-based applications such as security screens and radar,” says Stake.
The main difficulty is to maintain this technology, he continues, which requires precision engineering of metal parts to guide the waves accurately. He says it is difficult to secure sustainable financing to maintain a critical mass of expertise in this technology.
Strengthening Europe’s position in the space industry
“With EU funding, we were able to bring seven partners into the project, enough to push development in different parts of a complex receiver so the components are optimised to work together,” he says. EU support is boosting Europe’s position in the space race. Thanks to the outcome of TeraComp, participating SMEs such as Omnisys Instruments AB have already received commercial contracts for further instrument development.