NASA test robotic ice tools for use on Jupiter’s moon
31 March 2017
NASA has been developing new technologies for use on future missions to ocean worlds, including a subsurface probe that burrows through miles of ice.
Other technology includes robotic arms that unfold to reach faraway objects and a projectile launcher for even further samples. Each technology, developed by NASA’s Jet Propulsion laboratory (JPL) in California, focuses on obtaining samples from the surface of an icy moon, much like Jupiter’s moon Europa.
"In the future, we want to answer the question of whether there's life on the moons of the outer planets - on Europa, Enceladus and Titan," said Tom Cwik, who leads JPL's Space Technology Program. "We're working with NASA Headquarters to identify the specific systems we need to build now, so that in 10 or 15 years, they could be ready for a spacecraft."
"Robotic systems would face cryogenic temperatures and rugged terrain and have to meet strict planetary protection requirements," said Hari Nayar, who leads the robotics group that oversaw the research. "One of the most exciting places we can go is deep into subsurface oceans - but doing so requires new technologies that don't exist yet."
Brian Wilcox, an engineering fellow at JPL, designed a prototype inspired by ‘melt probes’ used on Earth. One of the issues is that they use heat inefficiently and having a probe that can’t manage its energy would eventually become frozen on the ice.
Wilcox invented a solution; a capsule insulated by a vacuum. Instead of radiating heat outwards, it would retain energy from a chunk of heat source plutonium as the probe sinks into the ice.
A rotating sawblade on the bottom of the probe would slowly turn and cut through the ice. As it does so, it would throw ice chips back into the probe's body, where they would be melted by the plutonium and pumped out behind it.
Removing the ice chips would ensure the probe drills steadily through the ice without blockages. The ice water could also be sampled and sent through a spool of aluminium tubing to a lander on the surface. Once there, the water samples could be checked for biosignatures.
"We think there are glacier-like ice flows deep within Europa's frozen crust," Wilcox said.
"Those flows churn up material from the ocean down below. As this probe tunnels into the crust, it could be sampling waters that may contain biosignatures, if any exist."
To ensure no Earth microbes hitched a ride, the probe would heat itself to over 482°C during its cruise on a spacecraft. That would kill any residual organisms and decompose complex organic molecules that could affect science results.
Robotics arms are essential for reaching samples from rovers and they never normally extend beyond 2-2.5m from their base.
Researchers at JPL thought of using a folding boom arm that can extend almost 10m. For samples even further than that, a projectile launcher was developed that can fire a sampling mechanism up to 50m.
All three technologies (the arm, the launcher and the ice-gripping claw) are designed to be used together. NASA claims that the claw could have a coring drill attached to it which will allow scientists to bore through up to 20cm of iced surface. After deployment from a boom arm or a projectile launcher, the claw could anchor itself using heated prongs that melt into the ice and secure its grip. That ensures that a drill's bit is able to penetrate and collect a sample.
Video courtesy of NASA’s Jet Propulsion Laboratory.