a new plasma drilling technology for the moon, asteroids

THE ENERGY GAMECHANGER
A NEW PLASMA DRILLING
TECHNOLOGY FOR THE MOON,
ASTEROIDS, AND MARS
Brage W. Johansen1,2, Pascal Lee2,3,4, Kjetil Naesje1, Brian J. Glass4, Wim Lekens1, Per H
Sorensen1, Oyvind Wetteland1, Christopher Hoftun2,5 and Kris Zacny6.
1
Zaptec Inc, 4021 Stavanger, Norway. Email: [email protected], 2Mars Institute, NASA
Research Park, Moffett Field, CA, USA, 3SETI Institute, Mountain View, CA, USA, 4NASA
Ames Research Center, Moffett Field, CA, USA, 5University of Stavanger, 4036 Stavanger,
Norway, 6Honeybee Robotics, Pasadena, CA, USA.
FIGURE 1: The Zaptec Plasma Drilling System in action. Left: Anchored to an asteroid or to one of the moons of Mars. Right: The high voltage, low power
sparks delivered through the Zaptec drill head create microscopic plasma channels that explode the rock. Images credit: Zaptec
SUMMARY
A new, plasma drilling technology is under development at Zaptec for
deep subsurface access, exploration, and sampling for science and ISRU
on the Moon, asteroids, Mars, and its moons.
Introduction
Future steps in the exploration of the Moon, asteroids, Mars,
and its two satellites, Phobos and Deimos, will require access
to the subsurface for in-situ science investigations, exploration,
sampling, and in-situ resource utilization (ISRU). The emplacement of subsurface devices (instruments, anchors, explosive
charges, etc.) might also be needed. Traditional drilling techniques used on Earth are difficult to apply in space, generally
because of their prohibitive requirements in equipment mass,
volume, and power, and their common reliance on gravity and
on the continuous circulation of a liquid H2O-based drilling fluids. While dry shallow drilling (down to depths of a few meters)
can be contemplated in the context of robotic missions [1],
traditional deep drilling appears prohibitively expensive, even in
the context of human missions.
The Zaptec Concept
We present a new plasma drilling technology and concept developed by the Zaptec, Inc. company to achieve practical, affordable, and reliable deep drilling on the Moon, asteroids, Mars, and
its moons. The drilling system comprises a freely advancing drill
head tethered by a power cable to a power source topside and
high voltage generator downhole. The drill advances by generating a high-energy density plasma at the drill head which breaks
down and pulverizes the target rock. A key enabling technology
is the system’s ability to deliver high energy plasma discharges
via low mass, small volume power transformers located in the
drill head section. Powder cuttings may be removed by circulating compressed CO2.
Zaptec on the Moon
On the Moon, the subsurface in the polar regions may be a
repository of volatiles of value to science and as a potential
resource for future human exploration. A Zaptec drill could
be deployed on a future robotic lunar lander mission, such as
Moon Express, or in the context of human missions. The fine
dust from drilling goes through the unit, is analysed, and then
sprayed into a dust exhaust in contact with the surface vacuum.
An alternative scenario is to expand the module with a processing unit which sorts out minerals from H2O/CO2 ice. The mineral
dust can then be used as raw materials for local manufacturing.
Zaptec on Asteroids, the Moons of Mars,
and Other Rocky Small Bodies
On asteroids, the subsurface may yield pristine asteroidal materials and potential resources for human exploration as well. The
moons of Mars, Phobos and Deimos, are expected to present
similar opportunities. Because the Zaptec approach does not
require weight on bit, it is able to effectively drill into any rocky
small body in microgravity [Fig. 1]. The Zaptec system is anticipated to reach 50 to 100 m depths with less than 250 kg of gear
topside and 1 kW of peak power.
MARS DEEP DRILLING UNIT
CUTTING DISPOSAL
COMPRESSOR
(~40kg)
POWER: RTG x 3
(~170kg)
CO2 INLET
COILED TUBING, 2000m
(~400kg)
sidered a “holy grail” objective for astrobiology. In spite of harsh
if not forbidding conditions for terrestrial life at the surface
of Mars today, the notion that there might be a thriving deep
biosphere on Mars merits serious consideration, if only because
an estimated 50% to 66% of the Earth’s total biomass resides in
a deep biosphere [2].
Our preliminary assessment of the suitability of a plasma drilling concept for Mars was established by examining how well it
might perform given the specific set of challenges presented by
operating on Mars, including conditions expected to be encountered both at the surface and in the subsurface. Deep drilling on
Mars faces first the obvious challenge of distance from the Earth
and constraints on equipment mass. Mars is an extremely remote and isolated drilling site by terrestrial standards, requiring
transportation across interplanetary space, EDL (Entry, Descent,
and Landing), and surface deployment solutions that are to say
the least extreme by terrestrial drilling standards.
Aside from this surface access difficulty, the greatest technical
challenges facing deep drilling on Mars compared to deep drilling on Earth stem from the low pressure and temperature conditions prevailing in the surface and near-surface environments
on Mars. These physical challenges translate in
turn into significant system development, operational, and logistical challenges [5,6]. Reduced
gravity on Mars (38%) compared to Earth is also a
factor for weight on bit while drilling.
LAB UNIT: GEOLOGY/BIOLOGY
(~100kg)
CO2 TANK
(~20kg)
CASING FLUID
(~200kg)
MOBILE EXTERNAL CAMERA
(~10kg)
CONDUCTOR CASING
(~20kg)
ZAPTEC DRILLING UNIT
(~25kg)
™
www.zaptec.com
FIGURE 2: Left: Zaptec deep drilling system capable of reaching a depth
of 2 km, deployed from a SpaceX Dragon-class landed capsule. Astronaut
shown for scale (Image Credit: Zaptec). Right: An important goal of deep
drilling on Mars will be to reach potential underground aquifers to search
for any extant life. Image credit: Mars Institute. (Image Credit: Mars Institute.
Background diagram: ESA).
Zaptec on Mars
On Mars, the subsurface might hold records of potential past
life on Mars that might be better preserved than at the surface
of Mars itself. The search for biosignatures and life on Mars is
guided by NASA’s Follow the Water strategy. The H2O ice-rich
subsurface on Mars likely transitions to liquid H2O-rich aquifers
at greater depth, which might offer habitats for potential extant
life on Mars [Fig. 2 Left].
The depth to liquid aquifers on Mars is estimated to range from
a few tens of meters (if briny solutions are involved and/or in
potentially active volcanic areas presenting elevated geothermal
gradients) to a few kilometers. Hoftun et al. (2014) summarize
deep drilling rationales and challenges on Mars, and suggest
that liquid aquifers might be reached at depths of less than 1 to
2 km beneath the floor of Valles Marineris and in recently active
volcanic provinces [4]. Reaching deep liquid H2O on Mars and
searching for life in this subsurface environment may be con-
An important requirement we placed on candidate Mars deep drilling systems is that they be
able to reach a depth of at least 2 km. To implement a successful deep drilling campaign on Mars
with autonomous systems, several complex technologies must be developed, integrated and work
together [8]. Conceptually the following systems
will be needed: 1) An autonomous unit at ground
level that can assemble, control and operate the
drilling process; 2) A tethered plasma drilling system that can
achieve 1-2 km down/up/diagonally to explore the subsurface
geology and 3) Topside or in situ sensors that can identify and
analyze bio signatures or life.
On Mars, the proposed Zaptec system will allow a depth of 2
km to be reached with less than 1 metric ton of surface payload
housed in a SpaceX Dragon-sized capsule and peak power
requirements of less than 2 kW [Fig.2 Right].
Next Steps
The lightweight, energy-efficient Zaptec drilling concept, which is
based on plasma channel drilling/electropulse, offers a promising and universal approach to planetary and small body drilling.
The concept will continue to mature with laboratory and field
tests over the next years.
From 2011-2013, we organized three International Planetary
Drilling Workshops convened by Norway’s Space & Energy network in Stavanger, Norway [3]. The development of the Zaptec
concept for planetary exploration applications benefitted from
these workshops. We plan to continue convening such workshops and encourage the international planetary exploration
community interested in subsurface access to participate.
ACKNOWLEDGEMENTS: We are grateful to Statoil ASA, Reelwell, Robotic Drilling Systems, and IRIS – International Research Institute of Stavanger for
valuable suggestions and discussions.
REFERENCES: [1] MEPAG Goal IV Science Analysis Group (2010), [2] Whitman, W. B. et al. (1998) Prokaryotes: The unseen majority. Proc. Natl. Acad. Sci.
USA, 95, 6578-6583. [3] Johansen B. W. et al. (2011), [4] Hoftun, C. et al. (2013) Deep Drilling on Mars: Review and Recommendations. Mars Inst. Tech.
Pub. MITP-2013-001, in prep. [5] Briggs G. and Gross A. (2002), Technical Challenges of Drilling on Mars: Center for Mars Exploration, [6] Zacny K. et al.
(2008), Astrobiology 8, number 3, [7] JPL/NASA (2012), insight.jpl.nasa.gov, [8] Glass B. et al. (2005), Proc. 8th iSAIRAS, [9] Vestavik O. et al. (2009), SPE/
IAD Drilling Conference and Exhibition, abstract #119491-MS, [10] Badger Explorer ASA (2012). [7] McKay C. P. (1997), Origins for life on Mars, 27, 1-3,
263-289).

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