Juice mission to Jupiter testing—down to the wire

Getting ready the Juice mission to Jupiter has concerned testing for every kind of contingencies, right down to the smallest of scales. This microscopic view exhibits floor harm to a tiny silver interconnector after being uncovered to erosive atomic oxygen identified to be discovered surrounding Jupiter’s moon Ganymede.

Attributable to launch on April 13 to start an eight-year journey to the most important planet within the solar system, ESA’s Jupiter Icy Moons Explorer, Juice, will spend three and a half years within the Jupiter system, and within the closing phase of its exploration will go into orbit across the largest Jovian moon, Ganymede.

Nevertheless, earlier observations by the Hubble House Telescope have revealed auroral glows round Ganymede as a result of presence of ‘atomic oxygen’—particular person atoms of oxygen on the fringes of the moon’s scanty ambiance, the results of customary oxygen molecules being damaged aside by the highly effective radiation belts surrounding Jupiter.

ESA supplies engineer Adrian Tighe explains, “Atomic oxygen can also be skilled in Earth orbit, attributable to oxygen molecules being dissociated by ultraviolet radiation from the Solar, and all Earth-orbiting missions under about 1000 km altitude are designed to withstand it. In the identical manner, the Juice group wanted to know that prone supplies might face up to the atomic oxygen the spacecraft would encounter within the mission’s Ganymede elliptical orbit phase.”

This take a look at targeted on silver interconnects used within the Juice solar arrays—connectors only a few tenths of a thousandth of a millimeter thick—wanting into their susceptibility to atomic oxygen publicity mixed with low-temperature ‘thermal biking’—repeated speedy temperature shifts. Of explicit concern was the danger of microcracks forming within the silver, which could result in failure.

“Silver is among the only a few metals prone to atomic oxygen erosion,” feedback Sam Verstaen of ESA’s Juice group. “However silver was additionally the popular steel for these Juice interconnects with the intention to keep the spacecraft’s magnetic cleanliness which is important for the optimum operation of our suite of in-situ science devices.”

Testing was carried out within the Low Earth Orbit Facility, LEOX, of ESA’s Supplies and Electrical Elements Laboratory, a part of the Company’s ESTEC technical middle within the Netherlands.

A one-of-a-kind facility in Europe, LEOX makes use of a laser to dissociate molecular oxygen into atomic oxygen at energy levels which can be equal to orbital velocity—7.8 km/s—to simulate the space environment as carefully as attainable.

“The overall results of atomic oxygen publicity may very well be seen clearly on the pattern interconnectors,” provides ESA supplies engineer Gabor Milassin, who carried out the testing. “Nevertheless it was demonstrated that this was solely a floor impact, and no main cracks have been noticed which might compromise the performance of the interconnects—the silver interconnects may very well be given a clear invoice of well being to go to Ganymede.”

The lab additionally labored on quite a few different Juice-related exams, together with evaluating multi-layer insulation, adhesive tapes and thermal management coatings. Juice introduced explicit issues in supplies phrases as a result of the mission will move from the high-temperature atmosphere of a Venus flyby, the place temperatures will rise above 200°C, right down to a a lot colder atmosphere round Jupiter.