Overview of Key Technologies for Small Bodies “Gas, Dust, and
Surface Sampling” and Recommendations for Technology
Development Priorities for 2013-2032 Timeframe.
Dr. Ashitey Trebi-Ollennu
Technical Group Leader,
Mobility & Manipulation Group
Mobility & Robotic Systems Section
Jet Propulsion Laboratory,
California Institute of Technology
4th Meeting of the NASA Small Bodies Assessment Group
The Westin Washington National Harbor, Washington D.C.
Tuesday, January 25, 2011
Copyright 2011 California Institute of Technology.
Government sponsorship acknowledged.
1. Overview of Key Technologies for Small Bodies Sampling • Fly Through/Flyby Missions
• Touch-and-go Missions
• Landed missions
2. Recommendations for Technology Development Priorities for 2013-2032
Timeframe• Smart Sampling Systems Technologies
• In Situ Microanalytical Technologies
• Sample Verification Technologies
• Small Bodies Physics-Based Modeling and Simulation
3. Conclusion
Outline
201/25/2011Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Fly-through missions reduce cost by eliminating the need for direct contact by the
spacecraft with the surface, but currently they can sample only the coma of comets. The
spacecraft flies over the planet, a single time or repeatedly, at an orbit sufficiently low so
that the material sought crosses its trajectory.
1. Current-State-Of-The -Art
1. The Stardust mission brought back small particles collected from hypervelocity particle
impacts into aerogel when flying through the coma of comet 81P/Wild 2.
2. This type of mission is perfect for
1. Collecting samples of a planet’s atmosphere or a comet’s tail.
2. A variant of this mission is one that the spacecraft creates a plume of material from an
airless body by impacting a probe into the surface then the spacecraft flies through the
plume to collect samples.
3. Technology Needs
1. Fly-through missions would benefit from spacecraft flying a probe into the small body to
generate sample material, e.g. via an impactor.
Fly Through/Flyby Missions
301/25/2011Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Touch-and-go (TAG) missions enable direct surface sampling during the brief touch
phase.
1. Current-State-Of-The –Art
1. JAXA’s Hayabusa mission attempted to acquire material ejected from the surface of
asteroid (25143) Itokawa after firing a bullet into the surface. Hayabusa demonstrated
a TAG mission scenario where the spacecraft briefly touched the asteroid for sampling.
2. This type of mission is perfect for1. Collecting surface samples from comets, asteroids or small moons, where the gravity
force is negligible.
2. Collecting surface samples from extreme planetary environments where spacecraft
exposure to the environment needs to be minimized.
3. Technology Needs1. Smart deployment mechanism designs to reduce severe and unpredictable forces and
torques experience by the spacecraft during the touch phase.
2. Sampling tool deployment mechanisms
1. Via ejector darts
2. Explosives
3. Subsurface Sampling tools
Touch-and-Go (TAG) Missions
401/25/2011Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Touch-and-Go (TAG) Missions
JPL TAG Sampling Tool Brush Wheel Sampler
Video of brush wheel sampler
Sample Acquisition
• Flight-like shaped canister
• 60° off alignment to 30° slope
• 50-80 kPa mixed pumice
• 0.5 kg/s collection rate
Sample Acquisition
• Flight-like shaped canister
• 30° slope
• 6 cm/sec horizontal velocity
• Glass bead simulant
• 0.22 kg/sec collection rate
501/25/2011Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Sample Acquisition
• Vaccum Chamber
• Glass bead simulant
• 0.22 kg/sec collection rate
Landed missions enable careful investigation of surface and subsurface samples but are
more costly due to the added complexity of landing and adhering to the surface in the
microgravity environment.
1. Current-State-Of-The –Art
1. Rosetta SD2 sampling system represents the state of the art in sampling to depth in
comets.
2. This type of mission is perfect for
1. Collecting surface and subsurface samples from planets, comets, asteroids or small
moons.
3. Technology Needs
1. Smart deployment mechanism designs to reduce sample tools preload requirements.
2. Sampling tools for sampling at depths of 1m or more.
Landed Missions
01/25/2011 6Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
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1. Robust systems for sample acquisition, handling and processing are critical to the
next generation of robotic explorers for investigation of planetary bodies.
2. Future missions will need to acquire surface and subsurface samples from comets,
asteroids, and small satellites such as Phobos and Deimos.
3. The breadth of technology challenges associated with sample acquisition for in situ
analytical surface exploration missions and sample return missions would severely
challenge the current state-of-the-art technology.
4. In addition, limited spacecraft resources (power, volume, mass, computational
capabilities, and telemetry bandwidth) demand innovative miniaturization and
advanced component design for integrated sampling systems that can survive and
operate in challenging environments (extremes in temperature, pressure, gravity,
vibration and thermal cycling).
5. NASA has very limited experience in planetary and small bodies sample
acquisition, in particular, astrobiological and subsurface volatiles (ice phase)
samples. For example on Mars, the experience is limited to Viking and Phoenix
scoops for sampling regolith.
Technology Development Priorities for 2013-2032
01/25/2011 7Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
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1. In general technology development timescales are long, so it will be most productive to
align technology development strategy on the expected general characteristics of
future missions.
2. We propose an aggressive and focused technology development strategy that aligns
with the following potential recommended mission profiles
1. Comet Surface Sample Return (CSSR) Mission (sample size 250 cc to380 cc)
2. Cryogenic Comet Nucleus Sample Return (CNSR) Mission (core at least 25 cm
deep and 3 cm across )(2021–2030)
3. Key Technologies
1. Cryogenic sample acquisition
2. Cryogenic sample handling (sample distribution/interrogation systems)
Technology Development Priorities for 2013-2032
01/25/2011 8Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Smart Sampling Systems Technologies for preserving sample integrity
1. Development of smart surface and subsurface acquisition tools that preserves the
integrity of the sample cores resulting in an increase in science return.
1. The scientific conclusions of missions that need to acquire surface and subsurface
samples depend on knowing why and how samples may be chemically altered during
collection or processing.
2. There is a need for significant improvement in preserving the integrity of subsurface
sample cores from initial acquisition to the end of the sampling handling chain.
3. There are several loss mechanisms that can chemically alter acquired samples. For
example, the ice content of samples taken on Mars can undergo “passive” sublimation
after the desiccated outer layer is removed to expose the permafrost substrate, and
“active” sublimation during tool interactions, followed by passive sublimation during
sample transfer, prior to analysis.
4. To ensure the validity of H2O composition measured in the icy sample all loss
mechanisms must be considered. There is currently no tool for capturing and measuring
these types of transient compositional or morphological altering events in situ during
sample acquisition and transfer chain.
Technology Development Priorities for 2013-2032
01/25/2011 9Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
In Situ Microanalytical Technologies
1. Development of in situ microanalytical technology that will enable transient
compositional or morphological altering events to be captured and detected in situ
during sample acquisition and transfer chain.
1. Another challenge is the lack of sufficiently sophisticated down-hole in situ analyses
technology as a result core samples must be transported to the surface for analyses.
Such surface analyses lead to additional technology and engineering issues that must be
addressed these include: the method of transporting and storage of excavated materials
to the surface; containment of sample during transport to surface; development of a
logging system; and sample analysis at the surface.
2. Microanalytical techniques should be applied in situ to identify physical textures and
surface chemical signatures of rocks, soils and ices.
3. Microanalytical characterization of sample spatial variability as a function of depth or
mineralogy
Technology Development Priorities for 2013-2032
01/25/2011 10Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Sample Verification Technologies
1. Development of in situ Sample Quantity Verification Technologies
1. There is a technology gap for sample acquisition verification systems for robotic sample
return missions.
2. A key mission success criterion for robotic sample return missions is that an assured
sample quantity (mass/volume ) has been collected before the return to Earth phase of
the mission is initiated.
3. For some robotic sample return missions sample acquisition verification must be done
autonomously without ground operations.
4. NASA's Genesis and Stardust robotic sample return missions successfully returned
samples to Earth without an in situ sample acquisition verification system on board the
spacecraft. Positive confirmation of successful sample acquisition and transfer was done
after the return of the sample capsule to Earth. These two missions are an exception
because of the types of sample they acquired, no direct interaction with the target body
was required and sample acquisition time was in order of several minutes.
Technology Development Priorities for 2013-2032
01/25/2011 11Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
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Sample Verification Technologies
1. Development of in situ Sample Content Verification Technologies
1. Sample elemental /mineralogical composition e.g. verify that sample contains at least
20% ice
Technology Development Priorities for 2013-2032
01/25/2011 12Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
ASTEROID Brush Wheel
Sampler
Technology Development Priorities for 2013-2032
Physics-Based Modeling and Simulation for Small Bodies Sampling
1. Provides a rapid and realistic test and design environment for comet stimulant
material, vacuum, low temperature and low gravity for testing and verifying
sampling concepts
1. TESTBEDS (- replicated easily, physics low/zero-g, hybrid testbeds, virtual field test, ops training)
2. ANALYSIS(- mechanisms, mobility, lighting, surface response, particles, parametrics, con-ops)
3. DESIGN( combined RCS, momentum wheel, leg systems, low-g systems, contact mechanisms, tethering systems, novel ideas, collaborative designs, evolutionary design)
4. BUILD & OPERATE ( V&V, visualize, maneuvers, targeting)
01/25/2011 13Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
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Key Features
• Side-canister 3-wheel
• Average of 0.71 kg/s with a
variety of test simulants (glass
beads, Bandelier tuff with 1 cm
rocks, fine and coarse pumice,
talcum, 4 mm styrofoam peanuts)
• Test conditions (slopes up to 30 ,
6 cm/sec horizontal velocity)
• Sampler model integrated into
physics-based simulation with
thrusters and robot arm
Robot arm sampling device interactions with
during touch-and-go sampling operation
Attitude control profiles
ASTEROID Brush Wheel
Sampler
JPL Robotics
Physics-Based Modeling and Simulation of Contact/Sampling
Technology Development Priorities for 2013-2032
01/25/2011 14Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Key Features• Mass: 4.35 kg
• Dimensions: 350 mm
diameter x 440 mm high
(extended)
• Maximum Hopping Velocity:
2.63 m/s
• Range of Hopping Pitch
Angle (from horizontal): 50º-
90º
• Range of Hopping Direction:
Full 360º
• Capability in 10 μG
environment:35 m vertical
hop/; 69 m horizontal hop for
50 hop angle
Steering
actuators
Spring-loaded
legs for
hopping
Internal
gyro for
stability
Platform body for
science payload
and controls
The hopping robot can hop at various angles with adjustable strengths to
achieve a desired vertical height or horizontal distance.
JPL Robotics
Physics-Based Modeling and Simulation of Hopping Mobility
Technology Development Priorities for 2013-2032
01/25/2011 15Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Key FeaturesEnvironment
• Gravitational Acceleration: 0.0005 m/s2
• Number of Particles: 4600
• Particle sand box: 1m x 1m
• Particle shape: Randomized
dodecahedrons
• Particle radius distribution: 7mm to 10cm
• Particle mass distribution: 10g to 30kg
Hopper
• Mass: 10kg
• Height: 50cm
• Foot Size: 6cm x 12cm
• Initial velocity in x-direction: .03 m/s
• Initial velocity in y-direction: .05 m/s
Hopping robot interacts with granular material on surface of asteroid
Physics-Based Modeling and Simulation of Surface Mobility
Technology Development Priorities for 2013-2032
01/25/2011 16Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
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In Conclusion…
1701/25/2011Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
1. In order to reduce development cost and risk for the potential Comet Surface
Sample Return and Cryogenic Comet Nucleus Sample Return (CNSR)
Missions we propose an aggressive and focused technology development
strategy in the following areas;
1. Cryogenic sample acquisition
1. Smart Sampling Systems Technologies for preserving sample integrity
2. Cryogenic sample handling (sample distribution/interrogation systems)
1. In Situ Microanalytical Technologies
2. Sample Verification Technologies
3. Small Bodies Physics-Based Modeling and Simulation
1. Technologies to simulate contact/sampling regolith interactions
2. Technologies that enables virtual field test, hybrid testbeds, and modeling of
comet stimulant material, vacuum, low temperature and low gravity.
2. For more information with ongoing updates see:
http://www-robotics.jpl.nasa.gov/
3. Please contact me if you would like to visit or work with us…
Conclusion
1801/25/2011Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319
Thank you. Questions?
1901/25/2011Dr. Ashitey Trebi-Ollennu, 4th NASA SBAG
CL#11-0319