Wayne Zimmerman

Cryobot: an ice penetrating robotic vehicle for Mars and Europa

NASAs desire to study and characterize the solar system will be done by in-situ robotic systems in the near term. Specific interest is focused towards finding water on Mars and understanding both the climatic and depositional history of the planet. In the case of Europa, scientists desire to unravel the mysteries surrounding the thick ice crust, its chemical properties, and subsurface ocean properties. For both Mars and Europa, the major scientific interest is whether there are signs of past or extant life in either the Mars polar ice, or the sub-ice ocean of Europa. The best way to explore either of these environments is a cryobot mole vehicle, which carries a suite of instruments suitable for sampling and analyzing the ice or ocean environments. JPL is currently developing a unique robotic vehicle, which utilizes gravity, and both passive and active heating systems to drive ice to a melt state, in order to facilitate mobility. This paper describes the science driven requirements for such a vehicle, a description of the cryobot design, and results of recent performance tests in both clean and dust laden ice. Although a radioisotope power system for a flight version of the cryobot is currently baselined, no decision on the final design of the flight cryobot will be made until the environmental review process is complete. Any use of the cryobot for Mars or Europa will conform to all environmental and planetary protection requirements.

Mars Volatiles and Climate Surveyor Robotic Arm

The primary purpose of the Mars Volatiles And Climate Surveyor (MVACS) Robotic Arm is to support the other MVACS science instruments by digging trenches in the Martian soil; acquiring and dumping soil samples into the Thermal Evolved Gas Analyzer; positioning the Soil Temperature Probe in the soil; positioning the Robotic Arm Air Temperature Sensor at various heights above the surface, and positioning the Robotic Arm Camera for taking images of the surface, trench, soil samples, magnetic targets, and other objects of scientific interest within its workspace. In addition to data collected from the Robotic Arm sensors during science support operations, the Robotic Arm will perform experiments along with the other science instruments to yield additional information on Martian soil mechanics in the vicinity of the lander. The experiments include periodic imaging of dumped soil piles, surface scraping and soil chopping experiments, compaction tests, insertion of the various end-effector tools into the soil, and trench cave-in tests. Data from the soil mechanics experiments will yield information on Martian soil properties such as angle of repose, cohesion, bearing strength, and grain size distribution.

A radioisotope powered cryobot for penetrating the Europan ice shell

The Cryobot team at JPL has been working on the design of a Cryo-Hydro Integrated Robotic Penetrator System (CHIRPS), which can be used to penetrate the Mars North Polar Cap or the thick sheet ice surrounding Jupiter’s moon, Europa. The science for either one of these missions is compelling. For both Mars and Europa the major scientific interest is to reach regions where there is a reservoir of water that may yield signs of past or extant life. Additionally, a Mars polar cap penetration would help us understand both climatic and depositional histories for perhaps as far back as 20 million years. Similarly, penetration of the Europa ice sheet would allow scientists to unravel the mysteries surrounding the thick ice crust, its chemical composition, and subsurface ocean properties. Extreme mass and power constraints make deep drilling/coring impractical. The best way to explore either one of these environments is a cryobot mole penetrator vehicle, which carries a suite of instruments suitable for sampling an...

Extreme electronics for in situ robotic/sensing systems

NASAs desire to study and characterize the solar system and small bodies like comets and asteroids will be done by in situ robotic systems in the near term. Work has already begun on the design of Mars and Europa mole penetrators, ultrasonic coring systems for Venus, and corers for comet nucleus sampling. Along with these in situ sampling systems come miniature science instruments that allow samples to be imaged microscopically, or sensor suites that break down and examine the chemical composition and DNA of samples. Both sample acquisition and instruments will be exposed to extreme radiation, temperatures, corrosion, or pressures. This paper describes these intended extreme mission environments, and discusses technologies being developed to enable systems to operate in extreme conditions.

A prototype ground-remote telerobot control system

A local-remote telerobot control system is described which is being developed for time-delayed groundremote control of space telerobotic systems. The system includes a local site operator interface for interactive command building and sequencing for supervised autonomy and a remote site: the Modular Telerobot Task Execution System ( MOTES ), to provide the remote site task execution capability. The local site system also provides stereo graphics overlay on video with interactive update of the remote environmental model. The operator selects objects in the environment to interact with and skill types to specify the tasks to be performed, such as grasping a module or opening a door.

Harpoon-based Sampling for Planetary Applications

Harpoon-based sampling techniques for sample acquisition from planetary rovers and aerobots have been developed. The approach enables access to samples on nearby steep terrain or from unstable mobile platforms with small mass and volume impacts. For rover-based sampling, alterative harpoon concepts were compared and the crossbow approach was selected. A prototype system was fabricated, mounted on a rover, and tested in the JPL marsyard. Also, two penetrator concepts were developed and tested for aerobot deployment to icy-regolith environments. One concept is a passive drop penetrator and the other is an active pyro-activated penetrator. Results of both the design and test efforts with the harpoon-based sampling systems are presented.

A post-Huygens Titan surface science mission design

With the Cassini-Huygens atmospheric probe drop-off mission fast approaching, it is essential that scientists and engineers start scoping potential follow-on surface science missions. This paper provides a summary of the first year of a two year design study (Chau et al., 2003) which examines in detail the desired surface science measurements and resolution, potential instrument suite, and complete payload delivery system. Also provided are design concepts for both an aerial inflatable mobility platform and deployable instrument sonde. The tethered deployable sonde provides the capability to sample near-surface atmosphere, sub-surface liquid (if it exists), and surface solid material. Actual laboratory tests of the amphibious sonde prototype are also presented

MSL Chemistry and Mineralogy X-ray Diffraction X-ray Fluorescence (CheMin) Instrument

This paper provides an overview of the Mars Science Laboratory (MSL) Chemistry and Mineralogy X-ray Diffraction (XRD), X-ray Fluorescence (XRF) (CheMin) Instrument, an element of the landed Curiosity rover payload, which landed on Mars in August of 2012. The scientific goal of the MSL mission is to explore and quantitatively assess regions in Gale Crater as a potential habitat for life - past or present. The CheMin instrument will receive Martian rock and soil samples from the MSL Sample Acquisition/Sample Processing and Handling (SA/SPaH) system, and process it utilizing X-Ray spectroscopy methods to determine mineral composition. The Chemin instrument will analyze Martian soil and rocks to enable scientists to investigate geophysical processes occurring on Mars. The CheMin science objectives and proposed surface operations are described along with the CheMin hardware with an emphasis on the system engineering challenges associated with developing such a complex instrument.

Technology portfolio options for NASA missions using decision trees

The portfolio allocation problem is pervasive to all R&D endeavors (i.e. all basic research sponsors need to be able to justify the anticipated incremental benefit/cost/ratios). The approach suggested is to utilize decision trees that capitalize on past experience of probabilistic fault/event tree analysis developed in the nuclear industry. A mission concept is formalized in terms of a sequence of event tree linkages and alternatives with probabilities/figures of merit of success and associated R&D costs ascribed at each link. For example, a search for life mission on Europa would involve site reconnaissance, site selection, landing, deep drilling through ice, small autonomous submersibles traversing the purported sea under ice, and in-situ life detection. Many advanced technologies not currently available would be required including long duration survivable systems (power, thermal, radiation), minimal mass autonomous systems (systems-on-a-chip, autonomous safe precision landing), life detection (including planetary protection) and communication of science data (ocean/ice/surface/orbiter/earth). For the Europa case, as an example, an event tree has been prepared in software (which means it is easily manipulated) with a variety of alternative technologies expressed. Mission objectives have been iterated with science teams; technology probabilities and costs at each link have been deduced and documented using information from Office of Space Science databases. These numbers are assumed to be the best estimates at present, which need to be reviewed and updated by NASA domain experts. The decision tree approach described, developed for an example long term (e.g. 2025) mission, is amenable to the introduction of time dependence if one is to consider investment strategies for nearer term endeavors, or programs comprised of time sequences of several projects.

In situ geochronology as a mission-enabling technology

Although there are excellent estimates of ages of terrains on Mars from crater counting, even a few absolute ages would serve to validate the calibration. Results with uncertainties, although much larger than those that could be achieved in labs on Earth, would be extremely valuable. While there are other possibilities for in situ geochronology instruments, we describe here two alternative technologies, being developed in JPL. There are two common features of both. The first is analysis by means of miniature mass spectrometer. The second is use of laser sampling to reduce or avoid sample handling, preparation and pre-treatment and equally importantly, to allow analysis of individual, texturally resolved minerals in coarse-grained rocks. This textural resolution will aid in selection of grains more or less enriched in the relevant elements and allow construction of isochrons for more precise dating. Either of these instruments could enable missions to Mars and other planetary bodies.