NASA has unveiled how a spacecraft bound for Europa will help to figure out if the Jupiter moon has the right conditions for life, as many scientists think it may.

The mission, expected to launch in the 2020s, will carry nine instruments chosen from 33 proposals, that are specially designed to find out if Europa is habitable, NASA announced Tuesday.

Evidence so far suggests that beneath Europa's icy surface is a salty, liquid ocean sitting on a rocky surface punctured by hydrothermal vents that could circulate heat and nutrients.

Europa from Galileo spacecraft

Jupiter's icy moon Europa, seen in an image taken by NASA's Galileo spacecraft, is thought to have a saltwater ocean that may be in contact with a rocky surface similar to Earth's ocean floor. ( NASA/JPL-Caltech/SETI Institute)

"After five billion years with conditions like that, it could be a very habitable place," said Jim Green, director of NASA's planetary science division, at the news conference. "We believe the environment is just perfect for the potential development of life."

He noted that hydrothermal vents at the bottom of Earth's ocean are full of life.

Curt Niebur, Europa program scientist, announced that the chosen instruments include:

  • A magnetometer and a plasma instrument that will measure the depth and saltiness of Europa's ocean, as well as the thickness of its ice shell, thought to be a few kilometres to 10 kilometres thick.
  • An infrared spectrometer that will map what Europa is made of, detecting materials such as salts, organics and water. Scientists hope it will figure out what the "brown gunk" on Europa's surface is made of.
  • An imaging system that will map the surface at high resolution.
  • Ice penetrating radar that will look for features like lakes and icebergs within the icy crust.
  • A heat detector that will find "hot spots" on the –116 C surface that could indicate the location of active features like hydrothermal vents.
  • A mass spectrometer and a dust analyzer that will measure chemicals in Europa's very thin atmosphere and materials from the surface ejected into space — including chemicals that might indicate the presence of hydrothermal vents.
  • An ultraviolet spectrograph designed to look for small plumes of water erupting from Europa's surface — essentially, samples of the ocean.
  • The Europa mission is expected to cost about $2 billion, not including the launch vehicle or rocket that will blast it into space. It will spend about a year on its journey to Europa, then three years making at least 45 close flybys.

Niebur noted that the spacecraft will not have any "life detectors" and that scientists don't even know what they could measure that could tell people with confidence that they have detected life.

However, Green said, the mission should give a good indication of how habitable the environment on Europa could be.

"If we do find life or indications of life that will be an enormous step forward in our understanding of our place in the universe," he added. "If there's life in the solar system and in Europa in particular, it must be everywhere in our galaxy and perhaps even in the universe."