Principal Investigators: Dr. Nancy D. Searby and Dr. Eduardo Almeida, NASA Ames
Humans are made up of many cells that perform a wide variety of functions while being subjected to the mechanical loads of daily living. For example, daily activities such as walking and running subject bone-forming osteoblasts to cyclic tension and compression via the cell-to-bone attachment points called focal adhesions. Bone continually remodels and adapts to these mechanical loads. In addition, bone-forming osteoblasts are sensitive to changes in gravity, from microgravity to hypergravity; this sensitivity may be the key reason astronauts lose bone. The objective of our research is to examine the cellular response to these changes in mechanical loading. Cells may respond by activation of key structural and signaling elements within the cell. Likely candidates for mediating cellular responses to mechanical loads include the cellıs skeleton, or cytoskeleton, cell surface adhesion receptors, and a complex array of intracellular signaling molecules regulated by tyrosine phosphorylation.
The Research Associate will participate in a project in which mechanical loads are altered and the cellular response studied. The project may involve development of experiment unique hardware necessary to complete the investigation, such as customized cell chambers or automated devices for use on the centrifuge. The Research Associate will assist in hardware development, perform cell biology experiments, and analyze data. The specifics of the project will depend on the Research Associateıs background. Background in cell biology and/or engineering, and general laboratory experience is desirable.
Principal Investigators: Dr. Jeffrey Smith, Dr. Richard
Boyle, Dr. Xander Twombley
This Research Associate(s) will
develop a computer simulation testbed for robotic exploration of the Martian
surface. With this physically-based software simulation, the student(s) will
test a variety of design options for future Mars rovers, including walking and
wheeled locomotion systems to search for potential evidence of life. The
overall goal is to develop a realistic simulation of biological exploration
using autonomous tools at remote sites. To accomplish this goal requires a
diverse team of theorists, engineers and biologists. This mission supports the
Astrobiology goal to search for life, or the building blocks of life, beyond Earth.
One or two Research Associates will be chosen for their
potential contribution to the team effort, which aims to produce publishable
results in a ten-week period. The team will consist of a Research Associate(s)
and NASA Ames staff with an appropriate skill mix that spans three major areas:
1) knowledge of biology and the search for life and its building block on Mars,
2) engineering of Mars rover systems and 3) software development of
physically-based computer simulations.
The investigators will look for a Research Associate(s) with expertise
in any of the following areas:
·
Computer Science: develop C++
software for robotic simulation using current tools available at the BioVIS
Technology Center;
·
Mechanical
Engineering/Robotics: work with real robotic systems and provide input to
simulation system with validated robotic data results;
·
Neuro-Engineering: develop
evolutionary robotics control systems based on genetic algorithms for
navigation of simulated terrain and completion of mission objectives;
·
Geology/Chemistry/Biology:
develop sensor/detector requirements of a targeted mission, such as a sample
return mission to Mars. Use these scientific objectives to define success
criteria for simulated robotic systems.
Objectives of this project:
·
Identify current and future
walking and wheeled rover designs under consideration for future robotic
exploration of Mars. Focus on a future Mars Sample Return mission.
·
Identify Astrobiology mission
objectives that rovers must accomplish, focusing on a future Mars Sample Return
mission.
·
Modify existing Mars rover
designs in simulation software to include current design considerations.
·
Develop self-guided control
mechanisms with the simulation environment.
·
Identify and design specific
sensors for navigational control and for data collection.
·
Explore new, original design
options considered by the team.
·
Perform validation testing of
appropriate design options in a Mars-terrain mock-up using design options that
have existing hardware to test.
Principal Investigator: Dr. Jennifer Dungan
____________________________________________________________________
CHARTING THE HISTORY OF EARTHıS EARLIEST MICROBIAL ECOSYSTEMS
Co-Investigators: David Des Marais, Dr. Leslie
Prufert-Bebout, and Linda Jahnke, NASA Ames Research Center
Microorganisms are the primary engines of our biosphere,
and so they play major roles in the biogeochemical cycles of carbon, oxygen,
nitrogen, sulfur and metals. The hierarchical organization of microbial
ecosystems determines the rates of processes that shape Earth's environment,
create the sedimentary and atmospheric signatures (biosignatures) of life, and
define the stage upon which major evolutionary events occurred. To learn how
microbes fulfill these roles on Earth and, potentially, other worlds, we must
therefore understand the structure and function of microbial ecosystems.
Photosynthetic microbial mats have been major players for billions of years.
They are self-sustaining, complete ecosystems in which light energy that is
absorbed over part of a diel (24 hour) cycle drives the synthesis of spatially
organized, diverse biomass. Thus microbial mats offer an opportunity to study
how microbial populations associate to control the biogeochemical cycles.
This project involves experiments with cyanobacterial
microbial mats that are maintained in a simulated natural environment. We will
explore various conditions that represent stages in the long-term
(billion-year) evolution of Earth's environment. The effects of seawater
composition, oxygen and dissolved inorganic carbon contents will be measured
for ecosystem properties such as population sizes, elemental cycling and gas
production. We will seek a better understanding of how the environment
influences biosignatures such as atmospheric gases and also chemicals and
minerals preserved in sedimentary rocks.
The student will participate in experiments with microbial
mats as part of a team. He/she will measure rates of growth and migration, as
well as the production and consumption of various key chemical compounds using
microelectrodes and chromatographs. These measurements will be interpreted as
components of ecosystem processes that can vary in response to changing
environmental conditions. The student will thereby contribute to an improved
understanding of how ancient photosynthetic ecosystems interacted with changing
environments and recorded their legacy.
Coursework in chemistry and/or biology, and a working
knowledge of word processing and spreadsheets, is necessary.
Principal
Investigator: Dr. Max Bernstein, NASA Ames
The tons of organic material that come to the Earth every day on meteorites and dust particles probably helped to make the Earth habitable, and possibly played a role in the origin of life. The organic compounds in meteorites (which are better characterized than those in dust particles) include amino acids (basic components of proteins) purine and pyrimidine bases (basic components of DNA and RNA), as well as a host of other complex organic molecules that resemble those that make up membranes and play key roles in our biochemistry. The origin of many of these molecules remains mysterious, but in recent years we have performed experiments that suggest low temperature radiation chemistry could account for many of these chemicals.
We investigate the formation and distribution of organic
molecules in space and consider the impact such molecules may have had on the
of origin life on Earth and the search for life on other planets. We perform laboratory experiments to
ascertain what kind of chemistry can be done by radiation processing of low
temperature ices. These experiments allow us to assess whether extraterrestrial
ices of the kind seen in interstellar space and the Solar System (such as on
Europa and comets) are the birthplace of organic molecules such as and amino
acids (Nature, 2002, 416, 401403), amphiphiles (Astrobiology, 2003, 2, 371,
Proc. Nat. Acad. Sci. 2001, 98, 815), quinones (Science, 1999, 283, 1135) and
other functionalized aromatic compounds (Meteoritics, 2001, 36, 351; ApJ.,
2003, 582, L25; ApJ., 2002, 576, 1115).
Understanding how
components of proteins and DNA could form in sterile space environments is also
of relevance to our search for life elsewhere in the Solar System, the great
task now ahead for NASA. If we find evidence of Life elsewhere in the Solar
System it will probably be in form of chemical biomarkers, quintessentially
biological molecules that indicate the presence of micro-organisms. While most
people think of molecules, such as amino acids, and nucleo-bases, as good
candidate biomarkers, these molecules are produced non-biotically in space and
are expected to be present on the surface of other planets, even in the absence
of Life. Understanding the range of non-biological organic molecules that could
act as false biomarkers in space is a prerequisite for any reasonable search
for biomarkers on other worlds.
Highly qualified candidates should combine laboratory
experience with a knowledge of, or an interest in, space science applications
that relate to astrobiology.
ADAPTING TO
UNUSUAL SENSORY ENVIRONMENTS
Principal Investigator: Dr. Robert B. Welch, NASA Ames
NASA
is committed to the use of virtual reality and teleoperator systems (e.g., the
Space Stationıs robotic arm) for training, simulation, and other tasks
necessary in space. Unfortunately,
however, many of these interactive technologies suffer from defects causing
users to experience initial misperceptions and errors in hand-eye
coordination. These technological
flaws and their perceptual and behavioral consequences will be with us for many
years to come and some may never be resolved.
The present research examines the ability of humans to adapt to an analogue of a virtual environment or teleoperator system in which a transformation between hand movements and visual feedback exists. A real life example is when an astronautıs rightward movement of a joystick causes the robotic arm to move off in a very different direction. A laboratory analogue is one in which in-out movements of a computer mouse cause a cursor viewed on a monitor to move off at a 40-degree angle, rather than its normal up-down path. Another entails the use of a prism to displace the visual field to one side, thus causing initial errors when attempting to reach for targets. We will investigate (1) the course of visual-motor adaptation to unusual sensory environments such as these, (2) the extent to which this adaptation is facilitated or inhibited by various factors known to influence other types of adaptation, and (3) the distinction between adaptation based on perceptual recalibration and adaptation based on visual-motor skill acquisition.
Principal Investigator: Dr. Tori Hoehler, NASA Ames
For more than 75% of its history, Earthıs biosphere consisted exclusively of microorganisms. During all of this time, microorganisms represented the sole biological agents of chemical change on Earthıs surface, and they continue to play a preeminent role in global chemical cycles into the modern day. If Earthıs history is any guide, our searches for fossil or extant life on other worlds are more likely to encounter evidence of microbial life than of ³higher² organisms. The farther from home we look for life, the more our search will depend on exclusively chemical forms of evidence. With this context, our group seeks to better understand the way in which microbial life affects the chemistry of its host planet. The systems we study must, of necessity, be terrestrial and modern. Wherever possible, however, we focus on systems that provide useful analogs of Earthıs microbially-dominated past, and seek to guide our studies and place our results in the context of astrobiological search strategies.
The summer researcher will aid in examining the factors controlling production and flux of potential biosignature gases from one or more systems including: hypersaline microbial mats (as analogs of the vast ³reefs² of cyanobacteria that dominated biological productivity on Earth for as much as two billion years); anoxic sediments (as the ultimate biological buffer on Earthıs oxidation state, and the ultimate filter on material passing into the rock record); chemosynthetic, anaerobic communities (as potential analogs of Earthıs earliest, pre-photosynthetic life forms). Daily activities will consist largely of analytical characterization of gas fluxes from these communities, using a variety of modern analytical tools. Significant time will also be spent discussing the general scientific and astrobiological context for the specific systems under study. Because much of our focus is on understanding the thermodynamic controls on biogeochemistry, a strong background in chemistry, including lab work, would be beneficial for a prospective summer researcher in our group.
TWO
PROJECTS IN BIOPHYSICS
Principal Investigator: Dr. Wenonah Vercoutere, NASA Ames
#1
CELLULAR BIOPHYSICS:
In this first project, the goal is to elucidate how the structure of DNA influences its molecular dynamics and how this may affect genomic responses to the mechanical stimuli that occur because of gravity. The hypothesis is that gene expression in mechanosensitive adherent cells is in part regulated directly by mechanical force transduction from the extracellular matrix to the nuclear matrix and protein-packaged DNA. This work will improve the context in which we understand the ability of adherent cells to detect, filter and respond to the mechanical stimulation of gravity.
#2 SINGLE MOLECULE BIOPHYSICS:
In this second
project, the objective is to elucidate how the dynamics of DNA structure are
altered by damage caused by radiation or oxidation at the single molecule
level, and determine ways to ameliorate this damage. The chemical changes to DNA caused by ultraviolet radiation
are expected to alter the molecular structure and/or dynamics sufficiently to
be individually identifiable using an aqueous ion-conducting nanopore
detector. This hypothesis is based
on previous work has shown that single nucleotide differences can be
discriminated using such a nanopore detector. This technique will vastly improve the ability to assess
damage to DNA, and provide a simple means to help characterize the risks of
radiation exposure in space. It
may also provide a method to test radiation protection.
Principal Investigator: Dr. Tim Castellano, NASA Ames
Small telescopes and commercially available charge coupled
device cameras are capable of achieving the necessary photometric precision to
detect transits of short period Jovian sized extrasolar planets. Only 1 of the
100 or so extrasolar planets currently known has been extensively studied
during its transits. Tim Castellano of NASA Ames and collaborator Greg Laughlin
of The University of California at Santa Cruz have developed a collaboration
with amateur astronomers, students and teachers, in order to continuously
measure the brightness of many stars that harbor short period extrasolar
planets. A small robotic observatory was developed last summer with the help of
undergraduate physics students from the NSF REU and NAFEO programs.
Summer 2005 work will concentrate on refining the observatory in order to improve its ability to measure small changes in the brightness of stars indicative or an orbiting planet, surveying promising candidates, and communicating techniques and procedures to amateur astronomers, teachers and students nationwide. A website that facilitates remote collaboration with amateurs, teachers and students worldwide: www.transitsearch.org.
Students with a familiarity with telescopes, Astronomy and Physics coursework, computer skills (including scientific programming, web development or networking), good problem solving & laboratory skills, and a willingness to work nights(!) are encouraged to apply.
LARGE SCALE COMPUTATIONAL SCIENCE AND ENGINEERING ON THE COLUMBIA SUPERCOMPUTER
Principle Investigator: Dr. Walter F. Brooks, NASA Ames
NASA has recently developed and put into production a 61.0TeraFlop peak Supercomputer, Columbia that is rated as the worlds 2nd fastest supercomputer. The system has over 600 users and is being used to address NASA's most challenging problems including major efforts in areas such as Shuttle return to flight, Space science, Nanotechnology, Aeronautics, advanced Aerospace vehicles design and Earth Science. The system is comprised of twenty 512 processor SGI Altix servers coupled by an infiniband fabric and supported with 440Tbytes of RAID. A portion of the system has been coupled together to form a 2048 processor Shared Memory Processor(SMP) , the Columbia system utilizes a Linux operating system. Research opportunities exist in the areas of system optimizations, tool development, code porting and scaling as well as visualization. The system will be coupled to the National Lambda Rail and additional opportunities exist in the areas of WAN and LAN development and deployment.
EarBot: BIOLOGICALLY INSPIRED AUTONOMOUS ROBOTIC CONTROL SL BioVIS TECHNOLOGY CENTER
Principal Investigators: Dr. Jeffrey Smith, Dr.
Richard Boyle, Dr. Xander Twombly
Planetary exploration
and construction will have limited on-site human resources, and must rely on
the use of supervised autonomous robots to provide the capabilities required to
establish a human presence. Autonomous
operation of robotic devices requires the capability to move rapidly and safely
through complex environments, maintaining stability while performing tasks and
acquiring scientific data. Next
generation autonomous explorers will gather information while in motion, and
robots performing ground-based construction must have the capabilities to
safely interact with targets and one another.
The vestibular
system is phylogenetically ancient, and enables creatures to maintain
equilibrium and spatial orientation while moving freely within the environment
on land, air and water. We propose
to develop the EarBot - a neural control paradigm inspired by vestibular
mechanisms and apply it to the control of autonomous robots. Using the nervous systemıs unique
ability to predict the effect of intended motion on its own motion sensors, the
EarBot will execute compensatory stabilization commands with effectively zero
execution lag time a highly robust control architecture. Robots imbued with
the EarBot will have greater capabilities to track moving targets (coupled with
video), adjust to rapidly changing terrain (balance reflex), and stabilize
instrumentation.
The EarBot will use
spatial arrays of tunable analog Micro-Electro-Mechanical Systems (MEMS)
sensors as inputs to circuits that mimic the feedforward, feedback, and
predictive mechanisms found in the brain, and use Field Programmable Gate
Arrays (FPGAs) to implement these neural circuits. FPGAs are reconfigurable computing, providing robust and redundant
computing resources. A major
characteristic of the EarBot is an energy conservation approach that allows for
adjustable, on demand power consumption. This approach is based on predictive
neural mechanisms that distinguish self-generated movements from quiescence,
and will extend the operational capacity for long duration missions.
Project
Milestones
Phase
I
Simulate
MEMS multi-axis inertial measurement systems as inputs to a neural network
model of the compensatory Vestibulo-Ocular Reflex (VOR). Use our previously developed robot
and terrain simulation environment to implement control mechanisms for stabilizing
a camera mounted on a walking robotic explorer on uneven terrain, including
compensation for self-directed motion.
Demonstrate efficacy of neural control concept and develop implementation
plan for sensor and processing architecture.
Phase
II
1) Construct sensor
systems with low power MEMS, design triggers that transition the EarBot between
high and low rates of sensor data collection, and construct neural circuitry to
calculate optimal inertia measurements from sensors. Implement control system
from VOR simulation in Phase I using the MEMS inputs and apply to stabilize a
multi-axis camera system. FPGA
implementations of neural circuitry.
2) Determine optimal geometry of sensors for
adaptive use of power resources during active exploration and quiescent
states. Develop predictive motion
component to pre-compensate for planned motion. Simulate balance reflex mechanism with multi-legged robot in
simulation environment.
3)
Preflight
field-testing phase - Test EarBot camera stabilization on multi-legged robot
and balance reflex control based on the earlier results. Embed and test on other appropriate
robotic systems.
Available
Projects for Astrobiology Academy Participants
1)
Testing
and characterization of MEMS sensor systems. A multi-axis sensor system to measure translational and
rotational accelerations has been constructed. The system consists of two ³sensor heads², each comprising 6
translational degrees of freedom (redundancy on all axes) and 3 rate gyros,
each of which sends signals to a TinyARM processor. The response of these sensors systems needs to be determined
and calibrated against the models used to calculate absolute position and
orientation from the sensor signals, and the processor system must be
programmed to process and communicate with a host system efficiently in
preparation for deployment on a mobile platform.
2)
Signal
processing models of sensor data.
A variety of signal processing methods are available to transform the
raw sensor data obtained from the MEMS devices into absolute position and
orientation data. An investigation
of the efficiency of different filtering techniques (linear adaptive, Kalman
filtering, etc) must be performed to determine the required processing methods
that must be implemented at both the peripheral (tinyARM) level and central
(host processor) to maximize signal accuracy while minimizing processor power
usage. Signal processing models of
the sensors will need to be developed in MATLAB and Simulink, and then
translated to the tinyARM and host processor systems as time allows.
Principle Investigator: Yvonne Pendleton, NASA Ames Research
Center
The overall goal of this
project is to develop high quality, easy to use web-based materials which
include new activities and descriptions of a multitude of Spitzer Space
Telescope images that can be integrated into the Voyages Through Time (VTT)
lessons which are already available through the following web site: http://www.voyagesthroughtime.org.
Our intent is to create
useful, highly relevant and timely educational materials from Spitzer results,
and to cast a wide net to reach teachers and students quickly. Two Academy students will work
with scientists and educators to develop ideas for activities and lessons based
on Spitzer data. The material
already developed for VTT during the four year long development process will
serve as an excellent jump start, illustrating both the level and content their
lessons should contain. The lessons created by the Academy students will be
reviewed by the evaluation services provided through the Origins EPO Forum at
Space Telescope Science Institute.
This project will bring together the strength of the NASA Academy at Ames Program, the highly successful integrated science curriculum Voyages Through Time (SETI Institute), and the astonishing results of the Spitzer Space Telescope in a unique manner of education outreach. By assigning two Academy students the opportunity to update VTT materials and create new activities and web material for teachers using Spitzer results, we anticipate a rewarding and educational experience for the Academy students. This work will also result in the development of a lasting resource for use by teachers and students worldwide which will explain and connect the Spitzer infrared world to the visible world around us.
NEW
ABLATIVE MATERIALS FOR THERMAL PROTECTION SYSTEMS (TPS) APPLICATIONS
Principle Investigators: Dr. Sylvia Johnson and Dr. Mairead Stackpoole
The Thermal Protection Materials and Systems (TPS) Branch is actively working toward developing new and improved TPS concepts. One of the current focuses is on development of new ablative materials for entry vehicles. Development of ablative materials has been at a very low level since Apollo and we are currently trying to address this issue. This project will focus on development of alternative lightweight ablator concepts using carbon substrates. Initial samples will be processed and key properties determined.
Students with a background in materials science, ceramic engineering or chemistry are encouraged to apply. Some experience in materials processing and characterization (thermal and mechanical properties) is desirable.