Although it’s still seven years away from reaching Jupiter, FRUIT JUICE The mission is progressing quickly — and a recent test run simulated the mission’s spacecraft flying next to Jupiter’s icy moon. Callisto.
It took off from Europe’s spaceport in French Guiana one year agoThe Jupiter Icy Moons Explorer, known simply as JUICE, is still in the interior. solar systemIt is preparing for a series of gravitational boosts that will put it in an orbit that will meet Jupiter in 2031. The first port of call will be the giant planet’s outermost Galilean moon, Callisto. This will be the first of 35 planned flights to the gas planet’s moon Callisto. in the booty And EuropeBefore the spacecraft settled into Ganymede’s orbit.
At the European Space Operations Center (ESOC) in Germany, the mission team is already preparing for this first flight, but is using an engineering model of the spacecraft to do so. This is an exact replica of the flight model currently orbiting in space, with the same hardware, software and instruments. The only difference is that it’s in a clean room in Darmstadt.
Relating to: The film ‘The Making of JUICE’ documents how scientists built a Jupiter-bound spacecraft against the odds
The problem facing JUICE, and indeed any mission to Jupiter, is time delay – how long does it take for radio signals to reach the spacecraft from Earth and vice versa. This relay can last 33 minutes when Jupiter is closest to Earth (at opposition) and 54 minutes when it is on the other side of the solar system. Thus, JUICE is programmed with software that can think and plan autonomously without waiting for commands.
An example of where JUICE’s autonomy will be vital is in observing Callisto’s surface features during flights. Since we won’t know JUICE’s exact location when it passes through Callisto’s gravitational field, the onboard computer must take over and fine-tune the spacecraft’s orientation so it can target individual surface features with its instruments to an accuracy of fractions of a degree. .
“We need JUICE to be able to react with its own ‘eyes’ and its own ‘brain,'” said Ignacio Tanco, JUICE’s Director of Flight Operations at the European Space Agency. press release. “Once Callisto appears in the navigation camera’s field of view, it should be able to identify key features on the lunar surface, rotate itself to point its instruments at them, and then continue to rotate to keep them in view as it passes by.”
The team at ESOC had to project computer-generated images of Callisto onto the model’s navigation camera, making the engineering model believe it was actually in space and flying past Callisto. The images mimicked the orientation and phase Callisto will have when JUICE makes actual flight in 2031.
Giulio Pinzan, Spacecraft Operations Engineer at the European Space Agency, likened it to connecting the engineering model to an immersive virtual reality headset and letting it move around in virtual space.
“The navigation software had to react to these images,” Pinzan said. “If he noticed that he was approaching Callisto at the wrong angle or looking slightly in the wrong direction, he had to try to correct those mistakes without our help.”
Three days were set aside for testing at ESOC and it was not expected to be a straightforward affair; The main purpose of these exercises is to eliminate the problems. Due to the complexity of the task, it was not possible to first test in a software simulator, where most of the gremlins could be eliminated. Instead, the JUICE team expected that the software would need to be rewritten, along with a lot of trial and error, to make it work.
But the engineering model was successful on day one; He successfully targeted images of Callisto and locked onto positions on the moon’s icy surface while performing a virtual flight, rolling to keep the moon in view.
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“We really have to praise our Flight Dynamics team,” Giulio said. “Their mathematical calculations were spot on and despite the lack of experience they could have gained by experimenting with the software simulator, they got us through with a clean flight on the first attempts. It was truly amazing. They surprised even us.”
Next step For the real-world JUICE mission, it’s August’s Lunar-Earth Gravity Assist, or LEGA for short. JUICE will fly past us first moon and will steal some of its orbital momentum, then pass by Earth less than 24 hours later and receive an additional gravitational boost to increase its speed. This is the first time this type of dual gravity support has been attempted, but since JUICE is the largest interplanetary spacecraft ever launched, it needs more help to move between planets. In 2025, JUICE will receive additional gravity support Venusand then just two more flights to Earth in 2026 and 2029 will give the spacecraft enough speed to exit the sun’s gravity well and eventually move towards Jupiter.