The Icebreaker expedition will deliver a robot to the Moon’s north pole to prospect for deposits of water ice and other volatiles sensed from orbit.
Astrobotic’s Polaris robot will land during north pole summer on Oct. 24, 2015, when patches of ground that are in cold shadow most of the year get brief illumination. This is where ice will be found closest to the surface, and when a solar-powered robot will get the sunlight needed to sustain exploration. Polaris will search for ice through 12 days until sundown.
The Apollo expeditions only visited six spots along the Moon’s equator, so the water, methane, carbon monoxide and other volatiles frozen at the poles went unnoticed for decades. Recent orbiting satellites and a NASA probe that impacted near the south pole showed that polar regions offer resources that could speed human settlement of the solar system. Water, oxygen and methane at the poles can be turned into rocket propellant to refuel spacecraft for their return trip to Earth; lunar propellant also can be shipped to Earth orbit to fuel Mars-bound crewed expeditions at less cost than launching propellant from the ground.
Polaris weighs 400 lbs. (181kg) and is equipped with twin video cameras. The stereo views aid in calculating location and provide immersive 3D video for audiences on Earth. The robot communicates directly with Earth receive stations using a pointed S-band antenna to send video and receive commands.
Polaris carries up to 175 lbs (80kg) of payload, such as a drill and instruments to analyze samples from the drill. To find the best spot to drill, two sensors will look for signs of hidden ice beneath the surface layer of dry soil. A neutron spectrometer will measure the number of neutrons given off by the first yard of soil beneath the rover; a dip in the reading indicates neutrons coming in from space are being absorbed by hydrogen (in water or methane) in ice beneath the robot. A near infrared spectrometer will look for variations in surface temperature that may hint at ice below.
Operators on Earth will update the rover’s exploration route based on these two sensors. Polaris will have autonomous intelligence to avoid obstacles and travel to the next point identified by Mission Control and its science team.
Because it will operate at the Moon’s north pole, the Earth as seen from the rover will periodically rise slightly above the horizon and then sink below it. Earth stations with the longest contact time are those at northern latitudes in Alaska and Scandinavia. For higher throughput when the Earth rises furthest above the horizon, Polaris will connect with the much larger dishes available at Earth stations in lower latitudes.