This control cover will protect MIRI against contamination. (Image: MIRI)
Repair is not an option
MIRI’s other Swiss-made part – its contamination control cover – must meet the same standard. This cover is designed to protect MIRI during the cool-down phase, before regular operation commences. It will also be used for later calibration of the instrument. “The contamination control cover mechanism has to function reliably, else the entire instrument will be rendered inoperable,” Glauser says. “Repairs are out of the question, as it’s far too far away from Earth.”
The development of the two components threw up a number of surprises. During inspection and approval of the contamination control cover, for example, it was discovered that 13 of the screws were coated with a material containing the heavy metal cadmium. In the eyes of the European Space Agency (ESA), this is a problematic material since it can become unstable in chemical compounds under a vacuum. “I then had to develop a special measurement procedure to show that the screws haven’t released any cadmium so far,” Glauser says.
Messages from the early universe
The new telescope, in the conception of which Simon Lilly, Professor of Experimental Astrophysics at ETH Zurich, was significantly involved, has been designed with four mission objectives in mind, which require extremely sensitive instrumentation. Among other things, the astrophysicists intend to use the JWST to gaze back to the origins of the universe with a view to discovering how the earliest stars and other structures were formed after the Big Bang. Furthermore, scientists want to investigate planets that might support life. “We won’t be using the JWST to look for new planets,” Glauser says, “but instead to take a closer look at ones we’ve already identified. To do this, we will directly measure the light of the planets spectrally.”
In his capacity as a research physicist, Glauser will now benefit from the favourable access to observation time granted to the MIRI consortium. “That’s the big advantage of being involved in the development of instruments like these. It will mean we can make a start on our projects ahead of other research groups.”
