Juice aces Callisto flyby test

Seven years from now, in April 2031, ESA’s Juice mission will fly previous Jupiter’s moon Callisto, providing scientists a tantalizing glimpse on the mysterious, cratered alien world.

Which may appear far off, however on this planet of spacecraft operations, it’s by no means too early to start out getting ready.

Groups at ESA’s ESOC mission operations middle in Germany lately ‘tricked’ Juice’s engineering mannequin into pondering it was already at Callisto as a way to put the mission’s autonomous navigation software program to the take a look at.

When Juice arrives at Callisto, the massive communication delay between Earth and the Jupiter system will imply that it can’t afford to attend for a reply from mission management if one thing goes mistaken.

Whereas we have now a good suggestion of the place Callisto might be in April 2031, we do not know its place exactly sufficient to ensure that Juice’s trajectory will take it by Callisto’s gravitational subject in precisely the precise method to line it up completely for high-accuracy scientific measurements.

Within the time it takes to ship and obtain messages between Jupiter and Earth, the path that Juice is pointing its distant sensing devices might drift up to now off target that science may very well be missed and key mission targets impacted.

Even a tiny discrepancy may very well be horrible for science, as a few of Juice’s devices have to be pointed at particular areas of Callisto inside a tiny fraction of a level as a way to make their measurements.

“We want Juice to have the ability to react with its personal ‘eyes’ and its personal ‘mind’,” says Ignacio Tanco, Juice Flight Operations Director. “When Callisto seems within the subject of view of its navigation digicam, it wants to have the ability to establish necessary options on the moon’s floor, rotate itself to level its devices at them, after which proceed rotating to maintain them in view because it flies previous.”

Groups at ESA fly spacecraft to new and thrilling locations throughout the solar system. To coach for necessary actions and to assist diagnose and resolve points skilled by spacecraft hundreds of thousands of kilometers away, they use a one-of-a-kind duplicate that continues to be on Earth. This ‘engineering mannequin’ is a precise copy of the {hardware}, software program, electrical systems, and devices which can be despatched into deep space.

The Juice workforce used its engineering mannequin to check the autonomous navigation software program that may preserve Juice on observe on the Jupiter system.

They ‘tricked’ it into believing it was at Callisto by projecting a collection of photographs of the moon onto its trustworthy duplicate of the spacecraft’s navigation digicam to see how it might reply.

These high-resolution photographs, generated by a pc mannequin, depicted Callisto within the actual orientation and phase that Juice will see it when it arrives seven years from now.

“It was not so simple as getting ready photographs upfront and enjoying a video in entrance of the navigation digicam,” says Giulio Pinzan, ESA Spacecraft Operations Engineer, who oversaw the exercise.

“The navigation software program needed to react to those photographs. If it observed that it was approaching Callisto on the mistaken angle or going through barely the mistaken path, it needed to try and appropriate these errors with out our assist.”

“That meant the view of Callisto needed to react to the spacecraft’s actions in real-time. We successfully strapped an immersive digital actuality headset to Juice’s digicam and let it transfer round independently inside this digital space.”

The groups from ESA and Juice’s producer, Airbus, allotted three days for the Callisto flyby take a look at. The spacecraft operators, scientists, and mechanical, electrical, and software engineers all anticipated to spend days encountering and fixing points earlier than lastly attaining a clear flyby through which Juice reacted precisely as they wished.

To make this take a look at much more difficult, they did not have entry to one of the vital necessary instruments within the spacecraft operations toolkit. Often, earlier than a posh take a look at like that is run on the spacecraft’s bodily engineering mannequin, it’s first run on a completely digital software program simulator of the spacecraft that has no bodily elements.

That is the place most points are encountered and resolved, and exams are solely run on the bodily engineering mannequin when operators have already got a good suggestion of what to anticipate.

“However this state of affairs is so advanced that it’s presently not possible to simulate with the Juice software program simulator,” says Giulio Pinzan. “We had been flying into this take a look at utterly blind.”

But, regardless of their expectations, the workforce succeeded on the very first try on day one. Juice’s navigation software program locked on to the proper areas of Callisto, saved its devices pointed straight at them, and safely maintained the proper trajectory because it navigated by the demanding flyby.

“We actually need to reward our Flight Dynamics workforce, specifically,” says Giulio. “Their mathematical calculations had been spot on and enabled us to cruise by a clear flyby on the very first try regardless of the dearth of expertise they might often achieve from experimenting with the software program simulator. It was superb, actually. They shocked even us.”

“The Airbus workforce additionally did a outstanding job establishing the engineering mannequin in time for the take a look at, whereas on the similar time offering us with all the small print that we would have liked to function the autonomous navigation system appropriately.”

The Callisto flyby is among the most demanding situations that Juice will face and is among the most tough to arrange and perform with the engineering mannequin.

The mannequin was transported from Airbus in France to ESOC in Germany in February. With the profitable completion of this closing take a look at, it’s now absolutely arrange, the ESA groups are absolutely educated on methods to use it, and it has formally been handed over.

The Juice workforce now want to verify that the flight mannequin behaves in precisely the identical approach because the engineering model by finishing up an identical take a look at in space. Nonetheless, the one alternatives to trace a big object with Juice’s navigation digicam will come throughout its planetary flybys.

The upcoming lunar-Earth gravity help in August this 12 months is just not an possibility for this take a look at. Throughout this double flyby, Juice will swing previous the moon after which Earth lower than 24 hours later as a way to steal power from each our bodies in fast succession. It’s a very delicate maneuver that has by no means been tried earlier than and all fingers will have to be able to react to any anomaly at a second’s discover.