Europa Clipper needs huge solar arrays to power it within the cold darkness of Jupiter’s shadow.
The Europa Clipper mission is the largest spacecraft NASA has ever built for planetary exploration, and has been fitted with huge solar arrays that will power its exploration of Jupiter’s icy moon Europa.
Europa Clipper was fitted with the solar arrays at Kennedy Space Center in Florida, USA, in August 2024.
Each of these solar ‘wings’ measures 46.5 feet (14.2 metres) long and 13.5 feet (4.1 metres) tall, and when they’re fully deployed in space, the spacecraft will span over 100 feet (30.5 metres), making it longer than a professional basketball court.
They have to be so big because they have quite a task ahead of them: powering Europa Clipper on its long journey to the Jupiter system and enabling its study of the liquid ocean beneath moon Europa’s icy crust.
Europa Clipper’s solar arrays are folded up for launch and will be deployed in space.
They’re so big they could only be opened one at a time in the clean room of Kennedy’s Payload Hazardous Servicing Facility.
90 minutes after launch, the arrays will unfurl over the course of 40 minutes and begin providing much-needed power to Europa Clipper.
What Europa Clipper’s solar arrays will do
Europa Clipper is due to launch in October 2024 and will journey for five years to get to Jupiter.
It will orbit Jupiter and fly by Europa multiple times, using its science instruments to study the icy moon.
Europa is of interest to planetary scientists because it’s one of a few moons in our Solar System known to have a liquid ocean beneath their icy crust.
And because liquid water is a key ingredient for life as we know it, that makes Europa an important place to look for conditions that could support life beyond Earth.
There has been evidence found of plumes on Europa, and the Webb Telescope detected carbon at Europa.
Out in the Jovian system, far from the Sun, the spacecraft will only receive 3–4% of the sunlight that Earth gets.
That’s why Europa Clipper’s solar arrays need to be so big.
Each solar array is composed of five panels and will together provide about 700 watts of electricity.
That may not seem that much: look at the front of your microwave and you’ll likely see a similar value.
But Europa Clipper’s batteries will store this power and use it to run its electronics, science instruments, communications equipment, computer and a propulsion system made up of 24 engines.
And to make things even tougher, it’s rather cold out there.
Europa Clipper’s hardware will operate under temperatures as cold as –240°C (–400°F) when in Jupiter’s shadow, which is much colder than even the coldest place on Earth.
“The spacecraft is cozy. It has heaters and an active thermal loop, which keep it in a much more normal temperature range,” says Taejoo Lee of NASA’s Applied Physics Laboratory, the solar array product delivery manager.
“But the solar arrays are exposed to the vacuum of space without any heaters. They’re completely passive, so whatever the environment is, those are the temperatures they get.”
Europa Clipper’s antennas
Europa Clipper’s solar arrays aren’t the only instruments that will be unfurling from a folded position.
The same is true of the spacecraft’s six antennas, which are affixed to the arrays.
They’ll deploy about two weeks after launch and will enable Europa Clipper’s radar instrument to search for water within and below the moon’s icy crust.
These antennas will unfold and span 57.7 feet (17.6 metres), perpendicular to the arrays.
“At the beginning of the project, we really thought it would be nearly impossible to develop a solar array strong enough to hold these gigantic antennas,” Lee says.
“It was difficult, but the team brought a lot of creativity to the challenge, and we figured it out.”