SBIR-STTR Award

Flawless operation of planetary mobility systems, excavation, mining and ISRU operations, regolith transport and many others depend on knowledge of geotechnical properties of the soil. Knowing, for example, the soil strength and its density and in turn fundamental soil parameters such as friction angle and apparent or true cohesion, will guide the design of the wheels and excavation systems and help to determine anticipated excavation energies, time, and forces. Nearly all planetary rovers to-date have experienced some type of problem due to the unknown nature of planetary regolith. The MER Spirit mission ended when the rover bogged down. The MER Opportunity rover barely recovered from a sand trap. MSL Curiosity spent over a month trying to find a safer route around a sand dune. Apollo Lunar Roving Vehicle got stuck and had to be lifted and placed on firmer ground while Lunokhod managed to recover from a 'near' stuck position. Honey Robotics, therefore, proposes to design and test a prototype geotechnical tool called the Stinger, that combines soil bearing strength measurements with shear test measurements. The Stinger instrument consists of a percussive cone shear-vane penetrometer capable of measuring near-surface and subsurface soil properties to a depth of 50 cm or greater. The cone deployment is percussive, because this approach reduces penetration forces, an important consideration when a tool is deployed in a low gravity environment from a small vehicle. During percussive cone deployment, the soil bearing strength is measured. The shear vane is initially housed inside a cone and it is pushed out whenever shear tests are required. When the shear vane is out, the cone-vane is rotated to measure shear strength of the soil. This measurement can be performed at any depth. Based on results of the breadboard testing, a preliminary design for a TRL6 Stinger GeoTool will also be realized. Anticipated

Benefits:
The Geotechnical Tool is imperative to gather essential engineering data to determine bearing strength, density, and trafficability of regolith. This is most useful to establish the stability of massive structures, set up resource mining operations, and survey exploration sites and routes. In addition, soil physical properties are used to help interpret surface geologic processes and to constrain the origins and formation processes of the soil. The Stinger is, therefore, not only a necessary surveying and exploratory tool, but a valuable scientific instrument as well, which would prove to be most useful for lunar missions and for ongoing exploration on Mars. In addition to penetrometer applications, the percussive mechanism could be used for rapid excavation (via an impact-actuated digging tool), setting anchors into the ground, and for rotary-percussive drilling systems. The system will be designed with a goal of minimizing system mass so that it might be mounted on small platforms like NASA's Centaur2 and also be human-deployable. Honeybee Robotics is a NASA-approved flight vendor and is therefore in the unique position to take a mechanism, such as that proposed, from low TRL to TRL 9, a successfully deployed flight unit. Honeybee has designed and built three critical flight components for Mars flight missions: Rock Abrasion Tool for 2003 MER, Robotic Arm Scoop for 2007 Phoenix Mars Mission, Sample Manipulation System and Dust Removal Tool for 2011 Mars Surface Laboratory. There is a general need for systems that provide rapid and more reliable soil characterization and the Geo Tool could provide this. Some of the applications include oilsands bearing strength assessment (this is required by law in the state of Alberta), environmental monitoring of industrial sites, agricultural surveys, and soil remediation. The military has expressed the nead for a rapid near-surface soil characterization tool, something that can be carried and deployed by a single soldier, with the data acquired and processed by someone with no or little training. Currently we are in the process of negotiating a contract that could start as soon as April of 2016.

The first lunar soft lander was Surveyor 1, in 1966. It had three tasks, one of which was to determine lunar surface bearing strength. Knowing the strength of the lunar surface was the single most important parameter - this essentially dictated whether landing on the Moon with significant mass like that of the Lunar Module was in fact feasible. During the Apollo program, astronauts used a Self-Recording Penetrometer (SRP) to measure geotechnical properties of lunar soil. One of the instruments of the 1970 and 1976 Soviet Lunokhold rovers included a shear vane geotechnical tool. Since 1976, there have been no geotechnical instruments deployed on any planetary body. Our intent is to provide a geotechnical tool that will allow us to begin exploration again. The Apollo penetrometer approach was excellent for greater depths, while the Soviet approach worked well for the near-surface. We combine the two approaches into what we call the Stinger, a percussive shear vane penetrometer capable of measuring near-surface and subsurface soil properties to a depth of 50 cm or greater. The objectives of Phase I were to design and build a simplified breadboard Stinger GeoTool and test it in lunar and Martian soil simulants to determine its applicability for robotic and human missions. The results of Phase I show not only accuracy and precision in determining soil properties, but also flawless execution of the breadboard design. This paves the way for the Phase II effort. The primary objective of the proposed Phase II effort is to develop a compact impact shear vane penetrometer - the Stinger - up to TRL5/6 to determine soil physical properties near the surface and down to 50 cm depth. In conjunction with the instrument development, a soil mechanics model will be formulated based on laboratory tests with the instruments, in soil simulants, and in vacuum conditions. Anticipated

Benefits:
Surface rover or ISRU missions: Mars2020 rover, Venus Mobile Explorer (VME), Lunar Resource Prospector. In addition, the tool could be deployed on landers such as Venus In Situ Explorer, Lunar Geophysical Network etc. Stinger could be adapted for Astronaut deployment as well. NASA ISRU and excavation mission would also need to determine soil properties. The tool can be used by DoD to perform soil strength assessment before landing planes and establishing camps (we are already commercializing a prior SBIR tool with DoD). Market also includes agriculture, road construction, mining (e.g. stability of tailings), and soil remediation.