The
MADD Project is an element of the Astrobiology Technology
and Instrument Development Program begun toward the end of
the first quarter of FY 2003. The project has the goal of
demonstrating a substantially automated, lightweight, low-power
drill that will be capable of acquiring aseptic core samples
from tens of meters below the surface of Mars.
Mining, Resource Utilization & Space Exploration conference
in Kentucky on November 2-4, 1993.
Deep drilling has provided us with important insights
into the history of Earth and into the question of how life
arose on our planet:
• Antarctic ice cores provide evidence of past climate
over many millions of years together with samples of micro-organisms
from the past
• Cores of sediments from the ocean bottom provide
similar evidence
• Ground water samples from great depth contain microorganisms
that evidently can survive and reproduce using chemical
energy sources (e.g., hydrogen and carbon dioxide) as opposed
to energy from the sun (for photosynthesis to start the
food chain)
• Samples to be acquired in the near future (under
strict aseptic conditions) from Antarctica’s Lake
Vostok (under 4 km of ice) may produce similar surprises
Together these samples from the Earth’s interior are
stimulating the formulation of new ideas about how life
may have evolved on Earth and on other planets as well as
about the causes and amplitudes of climate change.
Gaining access to samples from depth on Mars is expected
to be equally productive in addressing similar scientific
questions and certainly will be technically more challenging.
Deep drilling on Mars is a declared high priority for Mars
exploration and may well precede the return from Mars of
the first surface samples.
Ongoing Research relevant to Mars Deep Drilling Stimulated by a) the results of terrestrial deep
drilling, b) models of the martian interior that predict
the presence of brines at depth, and c) a feasibility study
of the technology needed to drill on Mars, NASA has been
supporting several drill technology developments for several
years. These include hardware developments (by Swales Inc,
and by Honeybee Robotics) supported by the Mars Technology
Program and a combination of hardware development and field
research supported by the Astrobiology Program (a Mars/Arctic
drill -- built by NASA JSC -- and the Honeybee drill to
be used at Rio Tinto in Spain). The Mars/Arctic research
project includes a unique laboratory effort aimed at understanding
the fundamental differences between drilling on Earth and
under extreme martian conditions.
In addition, the NASA Astrobiology Institute supports
an international program aimed at coordinating continental
drilling projects of astrobiological significance. Much
has been learned about the nature and ages of crucial
sedimentary successions but sampling for indicators of
early life (microfossils, biomarker molecules, stable
isotope ratios, organosedimentary structures, etc.) has
been hampered by the limited availability of unweathered,
unoxidized, and uncontaminated rock samples.
The Principal Challenges that we face in preparing
to drill on Mars
• Where to Drill?
– “Follow the Subsurface Water” will
be the guide and identifying optimal drill sites calls
for a combination of existing maps of the surface and
future GPR maps of the subsurface (to shallow depths and
to depths of a few kilometers) that will be acquired by
Mars Reconnaissance Orbiter and Mars Express, respectively.
– Ideally, geophysical (e-m) sounding would take
place at a drilling site prior to the start of penetration
• Given the poorly characterized environment presented
by the martian subsurface, basic physics research is needed
to compensate for our ignorance.
– Drill physics laboratory research with a complete
range of plausible materials and undertaken at ultra low
pressure and temperature
– Bit temperature control is vital given ubiquitous
martian ground ice
– Cuttings removal in the absence of drilling fluids
– No existing bit design meets our need re. wear
& range of material hardness
– No existing auger design is adequate for reliable
cuttings removal for all the materials we may encounter
– A variety of sensors need to be built into the
bit (e.g., for temperature measurements, resistivity of
clays near melting temperatures, accelerations) together
with a means of transmitting the data to the surface (a
problem for conventional drill strings) to allow autonomous
control
• Low Mass
– For robotic missions only a few tens of kilograms
will be available which immediately implies dry drilling
– fundamentally different from conventional drilling
where a fluid is used to cool the bit and to remove cuttings;
this different approach is a major reason for the required
fundamental lab research
– For deep penetration new drilling approaches are
likely necessary e.g., a cable tool approach to eliminate
drill string
• Power
– The limitations of solar power are not severe
because of the need to keep the bit from over heating
but rate of penetration will be very limited
• Automation
• Terrestrial drilling systems are fundamentally
different from the kind we will use on Mars so there is
little to learn from this direction. We need:
– Intelligent interpretation of sensor inputs/rapid
control loop
– Avoidance of catastrophic and problem situations
(e.g., melting and refreezing of ground ice, pebbles damaging
the bit, jamming due to auger failures)
– Dealing with abrupt changes in strata
– Optimization of drilling efficiency
– Core sample handling after acquisition
• Instrumentation
– In addition to already available sample analysis
instrumentation, it is highly desirable to develop miniature
logging instruments (camera, gamma ray spectrometer …)
to take full advantage of micro-boreholes drilled on Mars
• Testing
– All hardware developers carry out laboratory testing
under ambient conditions
– Field testing is also carried out at terrestrial
analog sites -- desert sites, Rio Tinto and Arctic
– Terrestrial analogs are only part of the answer
because testing in the unique small Mars test cell at
UCBerkeley has demonstrated fundamental differences when
drilling is conducted at martian pressures and temperatures:
heat loss processes are different; bits perform differently;
cuttings removal is highly sensitive to the ice content
of the material; and the performance of augers is also
different
– The UCB research (which can handle only penetrations
of about 15 cm) indicates the need for eventual full scale
testing of hardware and its autonomous control under ultra
low P and T; depth penetration of may meters will be required
to acquire confidence in any system i.e. to demonstrate
TRL 6 capability. Test parameters need to be defined for
HQ by qualified, un-conflicted scientists and engineers..
• Forward and Backward Planetary Protection
• Initially we need only be concerned about forward
contamination since this can lead to false positives (an
increasing concern as instrumentation achieves ever-higher
sensitivity). In time, and especially during the human
exploration phase, we will have to address backward contamination
issues – containment of cuttings and cores. Progress
has been made in developing tracer techniques for assessing
the radial depth to which contamination can penetrate
cores retrieved in analog environments from sandstone
and from ground ice. Similar experiments need to be conducted
in full scale testing under martian conditions to provide
the necessary confidence that we have an adequate means
of dealing with the problem.
Overcoming these interconnected challenges will benefit
greatly from an integrated approach. At the same time,
competition is a vital aspect of the development of martian
subsurface exploration capability. This competition is
provided by the three different hardware developers (Swales,
Honeybee, and NASA JSC) as well as developments in Canada,
Italy and perhaps elsewhere. Instrumentation development
is also competitively developed by the community. Given
this healthy intrinsic competition, we propose to carry
out an integrated effort to overcome the other challenges
including primarily:
Astrobiology and Geophysics, Drill Physics Research, Automation,
Full Scale Testing and Planetary Protection with close
cognizance of the other challenges: Drill System
-Hardware and Instrumentation.
Qualifications of NASA Ames and its Partners (NAI, UCB,
UK, LBNL, LPI, SETI Institute) to undertake such an integrated
Mars subsurface exploration project
-Astrobiology and Geophysics
NASA Ames has NASA’s core competency in Astrobiology.
It is the site of the NASA Astrobiology Institute which
already supports a terrestrial drilling project as well
as individual subsurface research projects at a number
of its constituent teams.
-The NASA Ames-led ASTID drill project has theoretical
geophysicist Stephen Clifford of the Lunar and Planetary
Institute as a key member of its team. The highly experienced
experimental geophysics group at Lawrence Berkeley National
Laboratory has links with UCB and with NASA Ames. An ASTID
proposal from LBNL is under evaluation.
-Drill Physics Research
The unique Mars drill physics laboratory at UC Berkeley
is supported by the NASA Ames-led ASTID drill project.
The University of Kentucky Mechanical Engineering Department
is a partner of Ames and is a world leader in predictive
performance models and optimization techniques for drilling.
An ASTID proposal from UK is under evaluation.
-Automation
NASA Ames provides the Agency with core competency in
automation and robotics. As part of an ASTID project,
Ames has begun the process of automating the NASA JSC
Mars/Arctic drill, starting with the UCB test set-up.
Ames is also undertaking the automation of the Honeybee
Mars/Rio Tinto drill and under an ASTID project has carried
out first field tests of a Honeybee drill at the Haughton
Crater.
-Full Scale Testing
NASA Ames has a tower building, originally intended for
full scale testing of Atlas launch vehicles, that can
be pumped down to martian pressures (~ 5 torr) (pumping
is carried out by the systems that operate the Ames arc
jets). This unique facility is able to accommodate apparatus
as high as 25 meters and would therefore be an ideal basis
for full scale testing of Mars drills that are intended
to penetrate to depths of a few to tens of meters. Cooling
of test rigs and test strata to appropriate temperatures
is deemed to be a straightforward engineering task.
-Planetary Protection
Ames has a long history of involvement in Planetary Protection
policy development and retains this expertise through
investigators affiliated with the nearby SETI Institute.
In addition, Ames Astrobiology CS conduct regular field
expeditions to collect samples of various kinds (including
permafrost cores) where contamination of the samples is
always an important consideration. This experience has
been translated into the field experiments of core contamination
mentioned above.
