Diving in the Alien Oceans of Europa
Fig1: EUROPA…HOMEWORLD OF THE ICEWOLVES AND ENDURANCE
Researchers from NASA and the University of Illinois at Chicago are preparing for interplanetary exploration. The space agency’s new robot submarine, Environmentally Non-Disturbing Under-Ice Robotic Antarctic Explorer (ENDURANCE) is currently in Antarctica’s permanently frozen Lake Bonney in the continent’s McMurdo Dry Valleys, it is ultimately destined for Europa-home world of the IceWolves and sixth moon of Jupiter.
ENDURANCE is designed to operate underwater below the ice. Its mission is one of exploration and navigation of dangerous alien environments that are not considered suitable for other forms of vehicles, to gather vital data regarding the offworld environment (eg samples of microscopic life) and to create three-dimensional maps of Europa’s undersea terrain. It was built by Stone Aerospace and was funded by NASA’s program Astrobiology Science and Technology for Exploring Planets (ASTEP. Weighing 1.3 tonnes it boasts 36 on-board computers, 56 sonar sensors and a plentiful supply of depth and guidance sensors. It is totally self-reliant and needs no instructions from mission control unlike planetary explorers such as Mars Rovers.
Europa is a scarred, frozen ice world made up of silicate rock with a saltwater ocean around 100km deep surrounding it (twice as much water as all the rivers and seas of Earth) and is completely covered by thick layers of ice between 10-50km deep. Lake Bonney was chosen because its extreme conditions are about as close as it gets on Earth to conditions ENDURANCE might expect on Europa. And if this and future expeditions prove a success, a submarine built along the same lines could be sent out to explore the ocean under the ice on Jupiter’s moon Europa by the year 2028.
Fig2: SUBSURFACE CROSS SECTION – EUROPA
ENDURANCE would arrive on Europa via an Orbiter. On touching down it would then drill a hole through the ice to reach the salt-water ocean beneath, which may be able to harbour life. The submarine’s sonar sensors work by scanning their surroundings to form a map of the areas it travels to. It would locate the most likely environments for life e.g. hydrothermal vents, by monitoring temperature, acidity and Oxygen levels. On-board computers would process the resulting photos, and image-recognition software would carry out the search for microbial life, which would show itself in the form of shapes or colours. Water samples would be analysed microscopically. First by dye and illumination, then if the water samples contain DNA, by glowing, indicating the presence of life. When the submarine arrives back at the Europan surface the information collected, would be uploaded to the Orbiter, from which point it would be transmitted to Earth.
Fig3: EARTH, MOON AND EUROPA
However there are many hurdles to overcome before an underwater submarine could be sent out to Europa. Endurance is at this time, too massive to send on interplanetary travel. Engineers would also have to overcome the problem of how to drill through Europa’s icy crust and find a safe method to lower the submarine through the ice to the ocean below.
Many scientists take the view that an orbiting spacecraft would be a better way to study Europa, sending an underwater probe at a later date. The Jet Propulsion Laboratory is currently working on a concept called the Europa Explorer. This would send out spacecraft in a low orbit to confirm the presence (or absence) of a liquid water ocean under Europa’s ice crust. It would also provide a map of both the surface of Europa and below the ice crust for to assist in future exploration.