Nasa is encouraging the public to send their names aboard a spacecraft that it is launching to Europa, an icy moon orbiting Jupiter.
Names will be engraved on the Europa Clipper craft, which will travel 2.8 billion km after a scheduled launch on October 10, 2024, from Florida.
There have already been more than 700,000 submissions from all over the world.
“Join the mission and have your name engraved on Nasa’s Europa Clipper spacecraft as it travels 1.8 billion miles to explore Europa, an ocean world that may support life,” said Nasa.
“Once all the names have been gathered, technicians in the Microdevices Laboratory at Nasa’s Jet Propulsion Laboratory in Southern California will use an electron beam to stencil them on to a dime-size silicon microchip.”
Each line of text will be smaller than the width of a human hair.
Nasa has launched a dedicated website for the public to register their names by December 31.
Mission to Jupiter's icy moon
Jupiter has 95 moons that are officially recognised, but Nasa said that there are thousands of smaller objects in the planet's orbit.
Europa is the sixth closest of the moons that orbit Jupiter.
Nasa's craft is being launched to study the moon's ice shell, the ocean beneath it and its composition and geology.
Scientists have been trying to understand the planet's moons better in the hope that maybe one will be able to support life.
The spacecraft will perform about 50 fly-bys of Europa – going as close as 25km above its surface – at different locations to help the craft scan the entire moon.
“Europa shows strong evidence for an ocean of liquid water beneath its icy crust,” said Nasa.
“Beyond Earth, Europa is considered one of the most promising places where we might find currently habitable environments in our solar system.”
An armoured spacecraft
The Europa Clipper will be the largest spacecraft built by Nasa for a planetary mission, weighing 3.2 tonnes without propellant.
The craft, its payloads and other electronics will be protected by a thick-walled vault – made of titanium and aluminium – to keep the structure safe from Jupiter's radiation.
Some of the scientific instruments aboard the Clipper include cameras and spectrometers that will take high-resolution images and composition maps of the moon's surface and atmosphere.
It will also carry a thermal instrument to pinpoint locations of warmer ice and potentially recent eruptions of water.
Previous missions to Jupiter and its moons
Only a few missions have explored Jupiter and its moons, including the Voyager programme in the 1970s.
The latest one was the Jupiter Icy Moons Explorer, launched by the European Space Agency earlier this year to study the planet's three largest icy moons – Europa, Ganymede and Callisto.
Nasa's Juno spacecraft, launched in 2011, is also studying Jupiter's moons.
