Reaching 1 m Deep on Mars: The Icebreaker Drill

The future exploration of Mars will require access to the subsurface, along with acquisition of samples for scientific analysis and ground-truthing of water ice and mineral reserves for in situ resource utilization. The Icebreaker drill is an integral part of the Icebreaker mission concept to search for life in ice-rich regions on Mars. Since the mission targets Mars Special Regions as defined by the Committee on Space Research (COSPAR), the drill has to meet the appropriate cleanliness standards as requested by NASA's Planetary Protection Office. In addition, the Icebreaker mission carries life-detection instruments; and in turn, the drill and sample delivery system have to meet stringent contamination requirements to prevent false positives. This paper reports on the development and testing of the Icebreaker drill, a 1 m class rotary-percussive drill and triple redundant sample delivery system. The drill acquires subsurface samples in short, approximately 10 cm bites, which makes the sampling system robust and prevents thawing and phase changes in the target materials. Autonomous drilling, sample acquisition, and sample transfer have been successfully demonstrated in Mars analog environments in the Arctic and the Antarctic Dry Valleys, as well as in a Mars environmental chamber. In all environments, the drill has been shown to perform at the “1-1-100-100” level; that is, it drilled to 1 m depth in approximately 1 hour with less than 100 N weight on bit and approximately 100 W of power. The drilled substrate varied and included pure ice, ice-rich regolith with and without rocks and with and without 2% perchlorate, and whole rocks. The drill is currently at a Technology Readiness Level (TRL) of 5. The next-generation Icebreaker drill weighs 10 kg, which is representative of the flightlike model at TRL 5/6. Key Words: Drilling—Sampling—Mars—Mars drilling—Subsurface exploration—Ice—Search for life. Astrobiology 13, 1166–1198. Table of contents Abstract 1. Introduction 2. The Martian Near Subsurface: Experience from Past Missions 3. Considerations When Designing a Drill for Mars Surface Operations 3.1. Science drivers 3.2. Environmental drivers 3.3. Planetary protection drivers 3.4. Technology drivers 4. The Icebreaker Mars Drill 4.1. Drilling depth 4.2. Selecting the best drilling method 4.3. Sample type 4.4. Components of the Icebreaker drill 4.4.1. Deployment boom 4.4.2. Z-stage 4.4.3. Drill head 4.4.4. Drill auger 4.4.5. Drill bit 4.4.6. Brushing station 4.5. Drilling software 4.5.1. Mission-critical events 4.5.2. Mission-noncritical events 4.6. Drill as a science instrument 5. Sample Acquisition 6. Sample Delivery 6.1. Five-DOF sampling arm and a scoop 6.2. Pneumatic sample transfer <