Jupiter's Europa and other ocean worlds in the Solar System have recently caught the scientific community's attention. Because of liquid water under their ice sheathes, these celestial bodies are the most likely places in our space neighborhood to develop life.
Several missions were planned to explore these ocean worlds, but most resulted in design failures. There are requirements to break through thick ice in a place far from the Sun, and the design constraints usually make it hard for the missions to achieve their goal of searching for life.
Exploring With Microbots
At NASA's Jet Propulsion Laboratory (JPL), engineers thought of sending a swarm of swimming microbots to explore the ocean depths beneath the icy crust. These microbots would be deployed from a main mothership bot.
One of the most likely mothership bots for this space mission is the Subsurface Access Mechanism for Europa (SESAME). As a thermo-mechanical drilling robot, it can pass through a thick ice shell in Europa, which measures up to 25 kilometers. This will be done by melting, cutting, and burning straight down to reach the juncture between the ice crust and its undersea ocean.
Once the bots get inside the ice crust, there is a chance that the drilling process will disrupt the surrounding environment and limit the usefulness of any data collected. For this reason, the idea of Sensing with Independent Microswimmers (SWIM) comes in. SWIM bots can deploy from the SESAME bot after breaching into the ocean. Once deposited into the water, they can travel autonomously from the mothership and explore areas up to a few hundred meters away.
Another challenge is the difficulty of transferring electric signals through water. JPL engineers proposed using an ultrasonic communication system for sending data from the mothership to the microbots and vice versa. The SESAME mothership can also potentially power the microbots using an underwater power transmission technique.
There is also an alternative method of developing a sound control system that will allow the bots to return to the mothership to recharge before proceeding to another mission into the deep. As the bots venture into the depths of the ocean world, they can potentially reach thermal vents similar to those found on Earth.
READ ALSO: NASA Hubble Space Telescope Found Water Vapor in Jupiter's Europa, Scientists Baffled
Evidence of Water in Europa
Europa shares many similarities with our planet. Like Earth, Europa is thought to have a rocky mantle, an iron core, and an ocean of salty water, unlike Earth. However, the ocean on this moon lies below a shell of ice, which is assumed to be 10 to 15 miles thick and about 40 to 100 miles deep.
The best evidence of the presence of an ocean at Europa was gathered by Galileo Spacecraft as it orbited Jupiter from 1995 to 2003. When the spacecraft made 12 close flybys of Europa, a magnetic field was detected by its magnetometer as the powerful magnetic field of Jupiter swept past the moon. Europa has no magnetic field, and scientists assume that this magnetic signature is likely due to a global ocean of salty water.
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