Kris Zacny

Drilling Systems for Extraterrestrial Subsurface Exploration

Drilling consists of 2 processes: breaking the formation with a bit and removing the drilled cuttings. In rotary drilling, rotational speed and weight on bit are used to control drilling, and the optimization of these parameters can markedly improve drilling performance. Although fluids are used for cuttings removal in terrestrial drilling, most planetary drilling systems conduct dry drilling with an auger. Chip removal via water-ice sublimation (when excavating water-ice-bound formations at pressure below the triple point of water) and pneumatic systems are also possible. Pneumatic systems use the gas or vaporization products of a high-density liquid brought from Earth, gas provided by an in situ compressor, or combustion products of a monopropellant. Drill bits can be divided into coring bits, which excavate an annular shaped hole, and full-faced bits. While cylindrical cores are generally superior as scientific samples, and coring drills have better performance characteristics, full-faced bits are simpler systems because the handling of a core requires a very complex robotic mechanism. The greatest constraints to extraterrestrial drilling are (1) the extreme environmental conditions, such as temperature, dust, and pressure; (2) the light-time communications delay, which necessitates highly autonomous systems; and (3) the mission and science constraints, such as mass and power budgets and the types of drilled samples needed for scientific analysis. A classification scheme based on drilling depth is proposed. Each of the 4 depth categories (surface drills, 1-meter class drills, 10-meter class drills, and deep drills) has distinct technological profiles and scientific ramifications.

Drilling in extreme environments : penetration and sampling on Earth and other planets

1 Introduction 2 Principles of Drilling and Excavation 3 Ground Drilling and Excavation 4 Ice Drilling and Coring 5 Underwater Drilling 6 Extraterrestrial Drilling and Excavation 7 Planetary Sample Acquisition, Handling and Processing 8 Instruments for In-Situ Sample Analysis 9 Contamination and Planetary Protection 10 Conclusions

The Icebreaker Life Mission to Mars: a search for biomolecular evidence for life.

The search for evidence of life on Mars is the primary motivation for the exploration of that planet. The results from previous missions, and the Phoenix mission in particular, indicate that the ice-cemented ground in the north polar plains is likely to be the most recently habitable place that is currently known on Mars. The near-surface ice likely provided adequate water activity during periods of high obliquity, ≈ 5 Myr ago. Carbon dioxide and nitrogen are present in the atmosphere, and nitrates may be present in the soil. Perchlorate in the soil together with iron in basaltic rock provides a possible energy source for life. Furthermore, the presence of organics must once again be considered, as the results of the Viking GCMS are now suspect given the discovery of the thermally reactive perchlorate. Ground ice may provide a way to preserve organic molecules for extended periods of time, especially organic biomarkers. The Mars Icebreaker Life mission focuses on the following science goals: (1) Search for specific biomolecules that would be conclusive evidence of life. (2) Perform a general search for organic molecules in the ground ice. (3) Determine the processes of ground ice formation and the role of liquid water. (4) Understand the mechanical properties of the martian polar ice-cemented soil. (5) Assess the recent habitability of the environment with respect to required elements to support life, energy sources, and possible toxic elements. (6) Compare the elemental composition of the northern plains with midlatitude sites. The Icebreaker Life payload has been designed around the Phoenix spacecraft and is targeted to a site near the Phoenix landing site. However, the Icebreaker payload could be supported on other Mars landing systems. Preliminary studies of the SpaceX Dragon lander show that it could support the Icebreaker payload for a landing either at the Phoenix site or at midlatitudes. Duplicate samples could be cached as a target for possible return by a Mars Sample Return mission. If the samples were shown to contain organic biomarkers, interest in returning them to Earth would be high.

Distribution of depth to ice-cemented soils in the high-elevation Quartermain Mountains, McMurdo Dry Valleys, Antarctica

Abstract We report on 475 measurements of depth to ice-cemented ground in four high-elevation valleys of the Quartermain Mountains, McMurdo Dry Valleys, Antarctica. These valleys have pervasive ice-cemented ground, and the depth to ice-cemented ground and the ice composition may be indicators of climate change. In University Valley, the measured depth to ice-cemented ground ranges from 0–98 cm. There is an overall trend of increasing depth to ice-cemented ground with distance from a small glacier at the head of the valley, with a slope of 32 cm depth per kilometre along the valley floor. For Farnell Valley, the depth to ice-cemented ground is roughly constant (c. 30 cm) in the upper and central parts of the valley, but increases sharply as the valley descends into Beacon Valley. The two valleys north of University Valley also have extensive ice-cemented ground, with depths of 20–40 cm, but exhibit no clear patterns of ice depth with location. For all valleys there is a tendency for the variability in depth to ice-cemented ground at a site to increase with increasing depth to ice. Snow recurrence, solar insolation, and surface albedo may all be factors that cause site to site variations in these valleys.

LunarVader: Development and Testing of Lunar Drill in Vacuum Chamber and in Lunar Analog Site of Antarctica

AbstractFuture exploration of the Moon will require access to the subsurface and acquisition of samples for scientific analysis and ground truthing of water-ice and mineral reserves for in situ resource utilization purposes. The LunarVader drill described in this paper is a 1-m class drill and cuttings acquisition system enabling subsurface exploration of the Moon. The drill employs rotary-percussive action, which reduces the weight on bit and energy consumption. This drilling approach has been successfully used by previous lunar missions, such as the Soviet Luna 16, 20, and 24, and United States Apollo 15, 16, and 17. These missions and drilling systems are described in detail. The passive sample acquisition system of the LunarVader drill delivers cuttings directly into a sample cup or an instrument inlet port. The drill was tested in a vacuum chamber and penetrated various formations, such as a water-saturated lunar soil simulant (JSC-1A) at −80°C, water-ice, and rocks to a depth of 1 m. The system was ...

Robotic Drill Systems for Planetary Exploration

The objective of the systems described in this report was to demonstrate that lowpowered drill systems could be fully autonomous in capturing subsurface samples, handing off samples to science instruments, and drilling. Two drills were designed with a logically selected suite of sensors and hardware which allowed for data to be collected both above and below the surface. Information received from these sensors was fed back to an intelligent drill control system to enable autonomy. Testing of these two drills at Mars analog sites demonstrated that fully autonomous drilling is possible with low-powered drill systems.

Novel Approaches to Drilling and Excavation on the Moon

The extraction of top surface and also of highly compacted material on the lunar surface is critical to the success of long term utilizat ion of resources for the production of oxygen, water and other consumables needed for propulsion and life support systems as well as for other ‘civil’ engineering applications such as building berms, roads, trenches. In-Situ Resource Utilization (ISRU) will become even more critical if the lunar polar craters are found to contain water ice. Apollo data clearly indicates highly compacted soil at shallow depths on the lunar surface, for which there is no existing experience in effective excavation under the vacuum and partial gravity environment. In this paper, we discuss two novel approaches for regolith excavation and transport. These include pneumatic and percussive systems. The main advantage of the pneumatic system is in efficient regolith transport (with 1 gram of gas at 3 psia over 6000 grams of soil can be lifted) while the main advantage of the percussive system is in reducing excavation fo rces by up to 40x. Both systems offer many advantages when used alone but also can be combined into a single highly synergistic system. For example, a percussive scoop could be integrated with the pneumatic lift of particles and the nozzle of the pneumatic excavator could be integrated with the percussive mechanism to enhance its deeper excavation capabilities.

Deep Drilling and Sampling via the Wireline Auto-Gopher Driven by Piezoelectric Percussive Actuator and EM Rotary Motor

The ability to penetrate subsurfaces and perform sample acquisition at depths of meters is critical for future NASA in-situ exploration missions to bodies in the solar system, including Mars, Europa, and Enceladus. A corer/sampler was developed with the goal of acquiring pristine samples by reaching depths on Mars beyond the oxidized and sterilized zone. The developed rotary-hammering coring drill, called Auto-Gopher, employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor rotates the bit to remove the powdered cuttings. This sampler is a wireline drill that is incorporated with an inchworm mechanism allowing thru cyclic coring and core removal to reach great depths. The penetration rate is optimized by simultaneously activating the percussive and rotary motions of the Auto-Gopher. The percussive mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) mechanism, which is driven by a piezoelectric stack, demonstrated to require low axial preload. The Auto-Gopher has been produced taking into account the lessons learned from the development of the Ultrasonic/Sonic Gopher that was designed as a percussive ice drill and was demonstrated in Antarctica in 2005 to reach about 2 meters deep. A field demonstration of the Auto-Gopher is currently being planned with the objective of reaching as deep as 3 to 5 meters in tufa formation.

Prototype rotary percussive drill for the Mars Sample Return mission

Since 1990s Honeybee Robotics has been developing and testing surface coring drills for future planetary missions. Recently, we focused on developing a rotary-percussive core drill for the 2018 Mars Sample Return mission and in particular for the Mars Astrobiology Explorer-Cacher, MAX-C mission. The goal of the 2018 MAX-C mission is to acquire approximately 20 cores from various rocks and outcrops on the surface of Mars. The acquired cores, 1 cm diameter and 5 cm long, would be cached for return back to Earth either in 2022 or 2024, depending which of the MSR architectures is selected. We built a testbed coring drill that was used to acquire drilling data, such as power, rate of penetration, and Weight on Bit, in various rock formations. Based on these drilling data we designed a prototype Mars Sample Return coring drill. The proposed MSR drill is an arm-mounted, standalone device, requiring no additional arm actuation once positioned and preloaded. A low mass, compact transmission internal to the housing provides all of the actuation of the tool mechanisms. The drill uses a rotary-percussive drilling approach and can acquire a 1 cm diameter and 5 cm long core in Saddleback basalt in less than 30 minutes with only ∼20 N Weight on Bit and less than 100 Watt of power. The prototype MSR drill weighs approximately 5 kg1,2.

Pneumatic Excavator and Regolith Transport System for Lunar ISRU and Construction

In this paper, we discuss our initial experimental results and preliminary theoretical model for transporting fine regolith particles as would be found in planetary environments (lunar or Mars) using high Mach number excitation, low pressure gases in tubing. This technique, coined “vacuum jet-lift method” selectively excites particles through transfer of gas momentum into the particles in the vicinity of a gas injection head. The resultant dustygas flow is subsequently transported along a tube containing the particles as the gas attempts to ultimately escape into the low pressure environment (controlled exit port to local atmosphere). At the gas injection point, a “leaky” seal between the injector and regolith or soil is permitted that allows some gas loss. The head loss through this leaky seal must be much greater than head loss through the rest of the transport system. We discuss experimental tests in ~5 torr atmosphere demonstrating regolith-mass-to-gas-mass transport efficiencies exceeding 1000:1 utilizing this technique. We also describe a theoretical model for scaling that demonstrates much higher efficiencies are achievable with lower pressure gases. Once the particles are entrained in the gas, the carrier gas can also be used to efficiently heat the particles as compared to attempting to drive heat flow directly through the highly insulating regolith.