Paulo Younse

An integrated coring and caching concept

An integrated concept for core sample acquisition and caching with potential application to a Mars caching mission has been developed. The concept utilizes a five degree-of-freedom manipulator arm to deploy a rotary percussive coring tool as well as to provide alignment, feed, and preload for the tool. The tool provides coring, core break-off, core retention and bit capture and release for bit change-out. In this concept, a sample is acquired directly into its sample tube in the coring bit and bit change-out is used to transfer the sample to the caching subsystem where it is sealed and stored. 1 2

Experimental results of rover-based coring and caching

Experimental results are presented for experiments performed using a prototype rover-based sample coring and caching system. The system consists of a rotary percussive coring tool on a five degree-of-freedom manipulator arm mounted on a FIDO-class rover and a sample caching subsystem mounted on the rover. Coring and caching experiments were performed in a laboratory setting and in a field test at Mono Lake, California. Rock abrasion experiments using an abrading bit on the coring tool were also performed. The experiments indicate that the sample acquisition and caching architecture is viable for use in a 2018 timeframe Mars caching mission and that rock abrasion using an abrading bit may be feasible in place of a dedicated rock abrasion tool.1 2

Sample sealing approaches for Mars Sample Return caching

Sealing methods for encapsulating samples in 1 cm diameter thin-walled sample tubes applicable to future proposed Mars Sample Return missions were investigated based on power requirements, operation in the Martian environment, dust tolerance, shock and vibration, maintenance of sample integrity, hermeticity, packaging requirements, mission risk, and ability for autonomy. Techniques implemented include a spring energized Teflon sleeve plug, a crimped tube seal, a heat-activated shape memory alloy plug, a shape memory alloy activated cap, a solder-based plug, and a solder-based cap. Testing will be performed on the prototypes to determine their sensitivity to particle contamination along the sealing surface, Helium leak rate, and survivability over a range of temperatures to help recommend sealing techniques for the proposed Mars Sample Return campaign.

Sample acquisition and caching using detachable scoops for mars sample return

Future Mars sample return missions would require technology to robotically acquire and cache multiple samples for delivery back to Earth. Anticipating the need to acquire samples and prevent cross-contamination, individual detachable scoops and caching boxes were designed for use with a rover. Four sample scoop/cache assemblies were mounted onto the back of Mars technology rover Sample Return Rover 2000 (SRR2K) at the Jet Propulsion Laboratory. A robotic arm on the rover was used to open and close the cache boxes. A clamping mechanism designed for the end effector of the robotic arm attached and detached individual scoops and performed the scooping for sample collection. The spring-loaded cache boxes had a labyrinth seal incorporated into the lid to provide a bio-barrier from external contaminants. The sample collection and caching system was tested, along with a cleaning protocol, to ensure cleanliness of the samples for life-detection studies August 2008 in Svalbard, Norway during the Arctic Mars Analog Svalbard Expedition (AMASE).

Thermal Testing of the Compositional InfraRed Imaging Spectrometer (CIRIS)

The CIRIS device is a Fourier Transform (FT) spectrometer that utilizes a rotating refractor to induce the time-varying path length difference in split light beams. This design allows the spectrometer to be extremely compact, and eliminates linear accelerations associated with traditional Michelson FT spectrometers. Compared to grating spectrometers, CIRIS is inherently radiation-tolerant and has high signal-to-noise in the mid- to thermal IR, making it ideal for outer planetary and primitive body missions. We have developed a small-scale thermal/vacuum testing facility for rapid testing of the CIRIS prototype and similar instruments in cryogenic conditions relevant to an outer planetary orbital environment. Here we present results from testing the CIRIS prototype and several infrared detectors, including thermal and electrical performance of the system.

A minimum scale architecture for rover-based sample acquisition and caching

The Minimum Scale Sample Acquisition and Caching (MinSAC) architecture has been developed to enable rover-based sample acquisition and caching while minimizing the system mass. The MinSAC architecture is a version of the previously developed Integrated Mars Sample Acquisition and Handling (IMSAH) architecture. The MinSAC implementation utilizes the sampling manipulator both for sampling and sample tube transfer. This significantly reduces the number of actuators in the sample acquisition and caching subsystem. A core sample is acquired directly into its sample tube in the coring bit. The bit is transferred and released on the rover. A tube gripper on the robotic arm turret pulls the filled sample tube out of the back of the coring bit and the tube is sealed. The sample tube is then placed in the return sample canister. A new tube is placed in the bit for acquisition of another sample.

Demonstration of autonomous coring and caching for a Mars sample return campaign concept

An end-to-end sample acquisition and caching system has been built and tested with capabilities applicable to sample acquisition and caching for a potential 2018 mission to Mars to collect samples for eventual return to Earth. The system provides full capability to robotically perform the end-to-end sample acquisition and caching process including placing a sample tube in a coring bit, attaching the bit to the sampling tool, coring a rock and acquiring the core sample in the tube, transferring the bit to the caching mechanism, removing the sample tube from the bit, sealing the filled sample tube with a plug, and storing the tube in the sample cache canister. This paper describes the hardware and robotic steps for the sample acquisition and caching process.

Sample tube seal testing for Mars Sample Return

Four sealing methods for encapsulating samples in 1 cm diameter thin-walled sample tubes were designed, along with a set of tests for characterization and evaluation of sample preservation capability for the proposed Mars Sample Return (MSR) campaign. The sealing methods include a finned shape memory alloy (SMA) plug, expanding torque plug, contracting SMA ring cap, and expanding SMA ring plug. Mechanical strength and hermeticity of the seal were measured. Robustness of the seal to Mars simulant dust, surface abrasion, and pressure differentials were tested. Survivability tests were run to simulate thermal cycles on Mars, vibration from a Mars Ascent Vehicle (MAV), and shock from Earth Entry Vehicle (EEV) landing. Material compatibility with potential sample minerals and organic molecules were studied to select proper tube and seal materials that would not lead to adverse reactions nor contaminate the sample. Cleaning and sterilization techniques were executed on coupons made from the seal materials to assess compliance with planetary protection and contamination control. Finally, a method to cut a sealed tube for sample removal was designed and tested.

Rover reconfiguration for body-mounted coring with slip

Active and passive approaches to accommodating moderate rover slip during coring, using a body mounted coring tool were studied. The work addresses the possibility of a 200kg rover experiencing moderate slip such as 1cm/minute while coring on a Martian slope using a body-mounted coring tool in a possible future Mars Sample Return mission. Rover slip while coring could be accommodated with passive compliance or active rover reconfiguration. A passive compliance device was designed that constrains the compliant motion of the tool relative to the rover to a plane with travel of approximately 1.5cm. Active reconfiguration relies upon wheel motion and a transverse linear stage to provide actuation of the coring tool position in the nominal wheel plane. The rover actively reconfigures utilizing six axis force feedback of the forces and torques on the coring tool. Rover slip is measured using Absolute Motion Visual Odometry (AMVO). Rover reconfiguration is demonstrated while coring on a slope with slip. However, the implemented body mounted coring tool approach is fundamentally limited: First, no out-ofplane actuation is considered, negating the possibility of rover roll and pitch compensation. Second, wheel-ground interaction could cause unintended system responses when wheel motion occurs, including motion in the uncontrollable roll and pitch degrees-of-freedom.

Planetary Sample Caching System Design Options

Potential Mars Sample Return missions would aspire to collect small core and regolith samples using a rover with a sample acquisition tool and sample caching system. Samples would need to be stored in individual sealed tubes in a canister that could be transfered to a Mars ascent vehicle and returned to Earth. A sample handling, encapsulation and containerization system (SHEC) has been developed as part of an integrated system for acquiring and storing core samples for application to future potential MSR and other potential sample return missions. Requirements and design options for the SHEC system were studied and a recommended design concept developed. Two families of solutions were explored: 1)transfer of a raw sample from the tool to the SHEC subsystem and 2)transfer of a tube containing the sample to the SHEC subsystem. The recommended design utilizes sample tool bit change out as the mechanism for transferring tubes to and samples in tubes from the tool. The SHEC subsystem design, called the Bit Changeout Caching(BiCC) design, is intended for operations on a MER class rover.