Helping answer our research questions for astrophysics and Earth observation, cannot be done without cryogenic technology. The cryogenics experts and cryogenic facilities at SRON play a hugely important role in the whole ‘in-house’ cycle from technology to instrument development for space science.
Many scientific discoveries are made by looking at light waves in wavelengths our eyes cannot see, with scientific instruments specially developed for that wavelength. Extremely hot gaseous atoms near the black hole and neutron star, for example, are seen in X-rays and UV. Molecules in the atmosphere of Earth or other planets in infrared. Even cooler gases and substances at the stage shortly before a star ignites, we want to see better in the mid- to far-infrared such as TeraHertz and submillimetre. New generations of increasingly sensitive instruments for these specific wavelengths, often operate at extremely low temperatures: cryogenic temperatures.
Space research requires cryogenic instruments
So for astrophysical research and Earth-based research in space, it is often necessary to make and keep an instrument very cold. Because if a measuring instrument itself is warmer than the weak signal you are trying to measure, the measurement is ruined.
It is also necessary for measurement methods that make convenient use of superconductivity for their signal detection, when a superconducting material, upon reaching a very specific cold temperature, suddenly allows current to pass through without a shred of resistance.
For our instrument development, we do a lot of cryogenic testing at temperatures as low as 50 milliKelvin. That is not even one degree warmer than -273 degrees Celsius. SRON has cleanrooms with high-tech facilities where at these temperatures we can test instruments for a whole range of wavelengths from optical to sub-millimetre.
SRON: the whole cycle of cryogenic instrument development in-house
At SRON, we do all the steps of cryogenic instrument development for space in-house. We translate scientific questions into a need for specific observing capabilities. We investigate fledgling promising technology and take it forward. We formulate instrument concepts, demonstrate their feasibility, and translate them into compact and robust instrument design, prepared for violent launches, high temperatures, vacuum and magnetic fields. We make the components and build them together into flight-worthy cryogenic instrument for science. We test it and prove the correct performance of the instrument (validation). We observe with the instrument and process the data obtained into a format that scientists can use for analysis.
Cryogenics in space missions and space technology
Many important space missions with cryogenic instruments have been and are being designed, developed and tested in SRON’s cryogenic facilities.
The NewAthena telescope measures X-rays from the extremely hot universe with the help of a deep-cooled detector system using superconductivity in Transition Edge Sensors (TES).
Superconductivity, and hence cryogenic technology, also plays a role in Kinetic Inductance Detectors, KIDs, which are now being further developed for future application in view of several future space missions
The HIFI instrument on the Herschel Space Telescope, focused on the weak signal of the cold and dark gas and dust between stars and galaxies, always operated between 2 and 10 Kelvin. (colder than -260 degrees Celsius). All cryogenic tests were conducted indoors at SRON.
HIFI was heterodyne: it mixed a hard-to-read signal with a reference signal at a frequency that is easier to process. Other heterodyne instruments to observe our planet and the universe are also cryogenic, such as the 66 receivers for the ALMA telescope park in Chile.
