The one-second window that could make or break mission to Jupiter
All space missions require split-second precision, but Europe’s ambitious journey to Jupiter has a tighter schedule than usual.
The Juice mission, which is looking for signs of extra-terrestrial life on the Jovian moons Europa, Ganymede and Calisto, has a miniscule one-second window to get into orbit when it launches in April.
The European Space Agency orbiter needs to harness the gravitational forces of Earth, Mars and Venus to slingshot it towards its target, and the planets must align perfectly, or the spacecraft could end up way off course.
In comparison, when the Artemis I mission launched to the Moon last November, it had a leisurely two hours to get off the ground.
Juice, which stands for Jupiter Icy Moons Explorer, is due for launch on April 13 from the European spaceport in Kourou, French Guiana, onboard an Ariane 5 rocket.
Justin Byrne, the head of science and Earth exploration missions at Airbus Defence and Space UK, which built the spacecraft, said: “The rocket is not powerful enough to send the mission straight to Jupiter, so we have to use energy from elsewhere, so we steal it from the planets.
“Those planets are only going to line up twice a year, in April and at the end of the summer. But when that lines up with the rotation of the Earth, we only have a one-second launch window each day where the physics of the whole universe lines up, so it’s quite a tricky thing.”
Jupiter lies around 391 million miles from Earth, on average, and it will take eight years for the spacecraft to reach its destination.
The system is believed to be one of the best places to look for extraterrestrial life because its ice moons are believed to contain vast icy oceans.
Once there, the orbiter will fly 125 miles above Callisto, observing the oldest moon in the Solar System, before making two flybys of Europa.
Beneath the ice crust of Europa is thought to lie a huge ocean of liquid water or slushy ice, that contains twice as much water as Earth's oceans combined.
This vast and deep body of water is widely considered to be the most promising place to look for life in the Solar System, and instruments on board Juice will be hunting for biosignatures like methane, which could hint that life is thriving beneath the icy surface.
On Earth, extremophile lifeforms have been found thriving near subterranean volcanoes and deep-sea vents, raising hopes that it could also exist in the underground oceans of Jupiter's moons.
After Europa, the mission will spend eight months circling Ganymede, the first time a spacecraft has orbited any moon other than our own.
Ganymede is the only moon in the Solar System known to generate its own magnetic field, so scientists are keen to work out how that is being achieved.
Just like Europa and Callisto, it harbours a hidden ocean, so researchers will also be looking for signs of habitability.
“Ganymede is the one that everyone is really interested in, because it has a magnetic field and it must have a molten core, but the other two have liquid under the surfaces an there is potentially life on all three,” added Mr Byrne.
“There are definitely signatures that we may be able to see. When the data starts coming back it will be really intensive, with bang, bang, bang new results. We will be swamped with new information.”
The magnetic field surrounding Ganymede has proved challenging to spacecraft engineers who had to construct a lead-lined centre to protect the electronics.
Mr Byrne added: “It has a massive magnetic field, 10,000 times stronger than the Earth, so it’s really the worst place to be putting a spacecraft. If you wanted to kill it, this is what you'd do.”
In all, Juice will make 35 fly-bys of the three moons, before finally carrying out a controlled crash into Ganymede. The team also wants to learn more about Jupiter, in particular why its famous Red Spot is shrinking.
Experts believe that the one-second window is achievable, but are worried that weather could scupper the launch. Too much wind or storms could cause delays and would mean waiting for the next time the planets align.
If the first window is missed there are several more opportunities in April, but after that the team would need to wait until August.