Content uploaded by Rodrigo Romo
Author content
All content in this area was uploaded by Rodrigo Romo on Jan 18, 2018
Content may be subject to copyright.
Planetary Basalt Field Project: Construction of a Lunar Launch/Landing Pad,
PISCES and NASA Kennedy Space Center Project Update
R. M. Kelso1, R. Romo1, C. Andersen1, R. P. Mueller2,t. Lippitt2, N. J. Gelino2, J. D. Smith2,
Ivan I. Townsend3, J. M. Schuler4, M.W. Nugent5, A. J. Nick5, K. Zacny6, and M. Hedlund6
1Pacific International Space Center for Exploration Systems (PISCES), 99 Aupuni St, Hilo,
Hawaii 96720, PH (808)935-8270; email: rkelso54@gmail.com, rfvromo@gmail.com,
canderse@hawaii.edu
2Swamp Works Laboratory, National Aeronautics and Space Administration (NASA), Kennedy
Space Center (KSC), Mail Stop: UB-R1, FL 32899; email: Rob.Mueller@nasa.gov,
Nathan.J.Gelino@nasa.gov, Jonathan.D.Smith@nasa.gov,
3Swamp Works Laboratory, Craig Technologies, Inc., Kennedy Space Center, FL 32899;
email: Ivan.I.Townsend@nasa.gov
4Swamp Works Laboratory, Enterprise Advisory Services Inc., Kennedy Space Center, FL
32899; email: Jason.M.Schuler@nasa.gov
5Swamp Works Laboratory, Sierra Lobo, Kennedy Space Center, FL 32899;
email: Matthew.W.Nugent@nasa.gov, Andrew.J.Nick@nasa.gov ,
6Honeybee Robotics, inc., 398 W Washington Blvd #200, Pasadena, CA 91103;
email: zacny@honeybeerobotics.com , hedlund@honeybeerobotics.com
ABSTRACT
Recently, NASA Headquarters invited the Pacific International Space Center for Exploration
Systems (PISCES) to become a strategic partner in a new project called “Additive Construction
with Mobile Emplacement (ACME)”. The goal of this project is to investigate technologies and
methodologies for constructing facilities and surface systems infrastructure on the Moon and
Mars using planetary basalt and other in-situ materials. The first phase of this project was to
robotically-build a 20 meter (66-ft) diameter vertical takeoff, vertical landing (VTVL) prototype
pad out of local basalt material on the Big Island of Hawaii. This VTVL pad is a technology
“proof of concept” demonstration project to show how a robotic precursor mission could viably
construct a VTVL pad on a planetary surface. Such VTVL pads can mitigate the effects of a
lander rocket engine exhaust plume impinging on the regolith surface, which can cause cratering
and high speed ejecta. In March, 2015 a “lunar sidewalk” construction was first completed in
Hilo, Hawaii, which proved that raw crushed Hawaiian basalt could be sintered into modular
paver elements. The Hawaiian basalt is very similar to granular materials found on Mars and the
Moon. Subsequently, PISCES and the NASA Kennedy Space Center (KSC) Swamp Works team
completed the basalt construction of a tele-operated, robotically-built basalt VTVL pad.
Construction was started in October, 2015 and successfully completed by the end of December,
2015.
PISCES and NASA KSC assessed various in-situ construction methodologies for the 2015
VTVL pad deployment demonstration using additive construction with Hawaiian basalt regolith.
Using the PISCES robotic rover (named “Helelani”) as the central platform for construction, the
team evaluated a variety of technologies for stabilizing the basalt surface, and then selected a
sintered inter-locking paver system to meet the requirements. New methods for sintered basalt
regolith paver production were developed and a tele-operated paver deployment mechanism
(PDM) was developed and installed on the PISCES rover to simulate VTVL pad construction
operations during an actual space mission. The rover was tele-operated locally in Hilo, Hawaii
and also from NASA KSC in Florida, which created valuable lessons learned for
future space missions requiring a VTVL pad capability.
INTRODUCTION
PISCES and the NASA Kennedy Space Center (KSC) Swamp Works completed the execution of
an innovative planetary robotic construction-demonstration project in the State of Hawaii in
December, 2015. This task is part of a larger NASA effort called “Additive Construction with
Mobile Emplacement (ACME)”. The goal of the ACME project is to investigate technologies
and methodologies for constructing infrastructure and facilities on the Moon and Mars using in
situ materials such as planetary basalt material. By using the indigenous regolith materials on
extra-terrestrial bodies, then the high mass and corresponding high cost of transporting
construction materials (e.g. concrete) can be avoided. At approximately $4,000 to $10,000 per kg
launched to Low Earth Orbit (LEO), depending on the launch provider used, this is a significant
cost savings which will make the future expansion of human civilization into space more
achievable. Part of the first phase of the ACME project was to robotically-build a 20 meter (66-
ft) diameter VTVL pad out of crushed basalt granular material on the Big Island of Hawaii. This
field demonstration showed that two dimensional (2D) horizontal planetary construction is
feasible with tele-operated robots, using only in-situ materials. In addition, a VTVL pad can
solve rocket plume regolith surface erosion issues and prevent lofted dust and ejecta, which
would otherwise cause a large dust cloud and high velocity regolith debris, impairing sensing
and navigation during precision landings on the Moon or Mars. These effects could also cause
damage to the lander vehicle or even loss of the vehicle and mission.
BACKGROUND
Spaceflight experience with landings on both Moon and Mars have indicated significant issues
that arise with rocket plume lofted regolith (planetary dust) when ascent/descent module
chemical propulsion rocket engines interact with the loose, fine regolith of the surface.
Analysis of both Apollo lunar landing imagery and computational models indicate that sub-
micron to 100 micron-size particles can reach ballistic trajectories with velocities of up to 2000
meters per second (m/sec) in the vacuum environment of the Moon. Analysis also indicated that
the Apollo mission descent engines on the Lunar Module (LM) excavated approximately 2000
metrics tons from the landing site. (Metzger, 2014). In addition, erosion of the surface was seen
in the recent Mars Science Laboratory (MSL) which successfully landed on Mars using a “sky-
crane” vehicle. (Sengupta, 2014). Landing large spacecraft (> 1,000 kg) on unstable and self-
eroded regolith surfaces creates a serious risk to a successful vertical landing, which could cause
loss of mission and crew. Takeoff is also dependent on suitable inclinations of the vehicle (the
NASA Apollo missions limit was 12 degrees from the horizontal) and a stable launch structure
foundation.
Such regolith erosion volumes and high ejecta velocities could also represent significant threats
in damage from sand blasting of co-located infrastructure of a landing site in the build-up of a
base/outpost. For example a Mars Ascent Vehicle (MAV) could be damaged from another space
craft landing which would jeopardize the crew’s journey back to Earth.
Figure 1. Photographic Evidence of the Mars Skycrane / Curiosity Lander
Descent Engine Rocket Plume Excavating and Lofting Dust at the Gale Crater
Landing Site. Photo: NASA/JPL
A mitigation approach is required for planetary surfaces where repeated launch/landings are
required in order to build up and operate a surface base site. One of those mitigation strategies is
to stabilize the regolith of the VTVL landing area to significantly reduce the risk of high velocity
ejecta particles created by the entry descent engines of launch/landers where high velocity gas
interacts with the regolith surface and entrains regolith particles in its flow path. Various regolith
stabilization strategies were investigated to determine a viable mitigation for these rocket plume
effects at a VTVL site.
DESCRIPTION
The Additive Construction with Mobile Emplacement (ACME) project, In-Situ Vertical Takeoff
/ Vertical Landing (VTVL) Pad task is a joint venture between NASA’s Space Technology
Mission Directorate (STMD) Game Changing Development (GCD) Program, NASA Kennedy
Space Center and the Pacific International Space Center for Exploration Systems (PISCES). The
VTVL pad task is one part of a larger ACME additive manufacturing effort using indigenous
materials. The technologies used in this task are also directly applicable to robotic horizontal
construction methods for building foundations for large in-situ concrete structures that will be
3D printed using Automated Additive construction (AAC).
The ACME project aims to increase the technology readiness level (TRL) of 2D horizontal
construction using robotic methods with VTVL pad in-situ materials and in-situ construction
from TRL 3 to 5. The goal of NASA/GCD, is to develop ACME for use on planetary surfaces,
to create both horizontal structures such as foundations, pads and roads as well as three
dimensional, vertical construction structures such as blast protection berms, un-pressurized
shelters and pressurized habitats. In addition to the TRL advancement of VTVL pad robotic
technology, the constraints placed on this task by the planetary surface environment and the
effects of rocket plume impingement and debris ejecta were the focus of the NASA work under
this task.
The TRL increase in VTVL pad technology is possible by combining the expertise, technologies,
indigenous Hawaiian volcanic basalt materials and goals of NASA Kennedy Space Center
(KSC), and the Pacific International Space Center for Exploration Systems (PISCES).
The end goals of the project were to:
• Be the first analogous terrestrial demonstration of tele-operated robotic VTVL pad
construction using planetary analogous basalt materials
• Investigate construction materials made from regolith, to identify optimal planetary
VTVL pad construction materials
• Advance the TRL of robotic VTVL pad hardware and processes to provide risk reduction
and capabilities to future missions
• Provide the gateway to fabricating VTVL pads, on demand, in precursor space missions
(prior to humans arriving) with in-situ resources, reducing the need for sizeable structure
launch up-mass
• Provide a significant return on investment by enabling future NASA missions (such as
large Mars landers (18-40 tonnes) not feasible without the capability to mitigate plume
effects such as via the construction of VTVL pads in situ (using planetary surface regolith
based materials), and doing so with significant (external to NASA) leveraging of funding
from the state of Hawaii, to realize a joint venture, in-situ demonstration in Hilo, Hawaii.
• Provide a first step towards evolving VTVL pad construction for use on space missions to
Earth’s Moon, Mars and beyond.
The current state-of-the-art in VTVL landing pads is TRL 3 (Analytical and experimental critical
function and/or characteristic proof-of-concept) with regolith materials being developed that are
as strong as, or stronger than regular terrestrial Portland cement based concrete. The goal was to
develop the technologies required to achieve TRL 5 (System/subsystem/component validation in
relevant environment).
This task, which was completed by KSC, and PISCES, defines the state-of-the-art for the
development of construction materials using in-situ Hawaiian materials (which are similar to
planetary materials). For the purposes of ACME, fabrication of 2D horizontal structures were
demonstrated by NASA KSC and PISCES, made from Hawaiian volcanic basalt materials; KSC
showed the feasibility of using regolith-derived materials in the construction of sintered basalt
pavers for a “bulls-eye” central landing pad area (3m x 3m) and concepts were generated for the
surrounding VTVL gravel pad apron (20 m diameter) stabilization methods.
The ACME project is relevant to the NASA Agency’s vision and mission as defined by NPD
1001.0, NASA Strategic Plan. The ACME project and its partnerships fulfill all three strategic
goals:
1. Strategic Goal 1: Expand the frontiers of knowledge, capability, and opportunity in space.
ACME will provide the background knowledge and capability necessary to build structures in
space using in-situ resources.
2. Strategic Goal 2: Advance understanding of Earth and develop technologies to improve
the quality of life on our home planet. Technologies to improve the quality of life on our home
planet is another goal of the ACME project. The synergistic work with the PISCES and NASA
will provide a VTVL robotic construction system with which pads and foundations will be
constructed; this technology has a vast amount of applications on Earth ranging from helicopter
landing pads to foundations, parking lots, roads, sidewalks, patios, plazas, driveways and other
2D structures. Additionally, PISCES has an agreement with the State of Hawaii to investigate the
construction of housing using local Hawaiian basalt, therefore avoiding importing cement from
the mainland.
3. Strategic Goal 3: Serve the American public and accomplish our Mission by effectively
managing our people, technical capabilities, and infrastructure. The ACME project leverages
significant matching funds from the State of Hawaii for PISCES. The ACME project leverages
NASA Field Center capabilities in contour crafting, simulants, and materials production and
characterization at NASA Marshall Space flight Center (MSFC); as well as regolith handling,
regolith construction material research, and autonomous systems at KSC.
The ACME project also fulfills specific NASA strategic objectives:
• Objective 1.1: Expand human presence in the solar system and to the surface of Mars to
advance exploration, science, innovation, benefits to humanity, and international collaboration.
The ACME VTVL pad robotic system was designed with planetary surface environments
considerations, analogous environments in Hawaii and relevant regolith simulant materials were
used in the experiments.
• Objective 1.7: Transform NASA missions and advance the Nation’s capabilities by
maturing crosscutting and innovative space technologies. The ACME VTVL task matured
terrestrial robotic construction technologies and basalt based materials to provide the capability
of producing 2D pad structures on other planets while utilizing in-situ resources for the
structures.
• Objective 2.3: Optimize Agency technology investments, foster open innovation, and
facilitate technology infusion, ensuring the greatest national benefit. PISCES will use
knowledge gained to facilitate infusion of the technology into the Hawaiian economy using local
indigenous volcanic materials.
• Objective 3.2: Ensure the availability and continued advancement of strategic, technical,
and programmatic capabilities to sustain NASA’s mission. The goal of the ACME VTVL task
project is to mature NASA’s robotic construction capabilities and thus significantly reduce the
amount of mass to be launched from Earth for the construction of planetary infrastructure.
The project success criteria were defined by the NASA In-Situ VTVL Pad requirements, as well
as the ACME team goals for the advancement of TRL for 2D horizontal structures.
• Reduction in launch mass by utilizing 100% in-situ resources (regolith as feedstock).
• Mature the TRL of:
o Basalt pavers for VTVL pads from TRL 3 to 5.
o Robotic basalt paver emplacement technologies from TRL 3 to 5.
o Gravel stabilization using in-situ materials from TRL 2 to 3.
• Ability to build an entire 20 m diameter VTVL paver pad/foundation structure in less
than 120 hours.
TECHNICAL APPROACH
System Description:
The purpose of the VTVL landing pad demonstration is to demonstrate the technologies and in-
situ materials required to tele-robotically emplace a VTVL landing pad on a planetary surface so
that subsequent missions can land with increased safety, reliability and repeatability. Without a
VTVL system the rocket plume may cause large craters to form underneath the lander vehicle
and eject regolith debris at velocities up to 2000 m/s.
The VTVL In-Situ Landing Pad element task consists of a “bulls-eye” central landing pad area
(3m x 3m) that will demonstrate the technology required for repeatable VTVL operations with
impinging rocket plumes. The apron area surrounding the robust bulls-eye pad area (20 m
diameter) will be capable of supporting an off-nominal, contingency landing (where the vehicle
has drifted), but is not designed to have the extended lifetime of the bulls-eye material since it is
for contingency landings only.
Additionally, the PISCES sees a potential to expand basalt rebar technology into terrestrial
applications within the State of Hawaii as an emerging economic development project for civil
engineering. Currently, Hawaii imports iron rebar from China, but has experienced the high
expense of transportation and quality issues with the imports (rust, manufacturing quality, etc).
Given the fact that the Hawaiian isles are made of basalt material, it follows that there may be
industrial potential for eventually fabricating basalt rebar in Hawaii for a substitute to iron rebar
for civil engineering projects within the State. This will provide the technology, the unique
partnership, and testing activities leading to a new and viable economic activity in the state of
Hawaii, which could result in a reduction of imports and an improved balance of trade.
ROLES AND RESPONSIBILITIES
The following outlines the roles and responsibilities of PISCES in this project:
Provides high quality lunar analogue test site (selection and site preparation)
Provides large tele-robotic operating systems for construction
Provides overall engineering integration & Interface Control Document (ICD) between
the robotic rover and the construction implements hardware
Responsible for procurement of a kiln and paver production
Provides operations control for robotic construction leveling, grading, paver deployment
Performs loads tests / verification after completion
The following outlines the roles and responsibilities of NASA KSC:
Provides system requirements and Concept of Operations (ConOps)
Develops the design and manufacturing protocol for basalt paver
Mold design, interlocking, thermal heating/cooling profile
Provides an adjustable bulldozer leveling blade
Design and development of the rover Paver Deployment Mechanism (PDM)
Provides technical support personnel to PISCES for landing pad construction phase
Possible tele-operation of the rover from KSC Swamp Works via NASA communications
router, using the Space Network Research Federation (SNRF) system.
LUNAR LANDSCAPE CONSTRUCTION: “MOONSCAPE”
PISCES developed and completed the construction of a KSC-designed lunar landscape. The
lunar landscape was the designated location for the tele-robotic construction of the VTVL pad.
PISCES located the test site at the Puna Rock Quarry in Kea-au, Hawaii (near Hilo). Basalt fines
(sub 150 micron) were brought into the site as working material for the center bulls-eye. The
outer apron areas of the moonscape were filled with a mix of basalt sand, gravel and larger
particles.
Figure 2. Oblique Computer Aided Design (CAD) view of PISCES VTVL Basalt Moon-
Scape with simulated Hills and Craters
Figure 3. Aerial View of actual PISCES in-situ VTVL Basalt Moon-Scape
BASALT VTVL PAD CONSTRUCTION OPERATIONS
The Strategic partners shown in Table 1 all contributed to the VTVL project, with the indicated
responsibilities. The combined effort and commitment of these organizations enabled a
successful joint venture to prove the feasibility of tele-robotic construction of a VTVL pad.
Table 1: VTVL Pad Joint Venture Team Members and Contributions
Partner
Project Responsibility
PISCES
Provided planetary rover, basalt test site, paver fabrication and test
operations
NASA-KSC
Developed overall test requirements, paver design, fabrication
method and molds, developed gripper for paver deployment, PDM,
integration of the robotic arm, design of lunar landscape, hot fire
test requirements and solid propellant rocket test stand
Honeybee Robotics, Inc.
Provided robotic manipulation arm for deployment of pavers
Argo, Inc. – Canada
Manufacturer/provider of basic robotic rover system to PISCES
County of Hawaii R&D
Co-funding to PISCES for research and development in basalt
material as a construction substitute versus concrete
VTVL Pad System Construction Concept of Operations:
The construction operations were completed in Hawaii by PISCES at a basalt rock quarry
site. The following phases were used to achieve the final configuration of the pad.
PHASE 1 – Prepare the “lunar” analog site for construction by leveling and grading with
PISCES rover/KSC blade – Full VTVL pad perimeter
1. Develop VTVL System Concept. 20m x 20m pad with 3mx 3m bulls eye area.
2. Select VTVL Site. Puna Rock Quarry, 16-669 Milo St, Keaau, HI 96749
3. Evaluate Geotechnical Foundation. Basalt rock at 200 feet height above sea level,
with good drainage.
4. Secure perimeter: Ensure that VTVL operations can proceed without hazards to
work force or the public. Clear Rocks and deposit dry basalt regolith fines
5. Site preparation. Tele-robotic leveling with robotic rover mounted bulldozer blade
6. Site preparation. Tele-robotic grading with robotic rover mounted bulldozer blade
Figure 4. PISCES rover with KSC leveling back-blade
PHASE 2 – Compaction and fine finish - PISCES’ blade on rover with compaction
roller attached – Bulls Eye Pad Area
7. Site preparation- Tele-robotic compaction and fine blading for final foundation
configuration
Figure 5. Robotic Compaction Operations
Figure 6. Robotic leveling and grading
Soil Compaction:
Soil compaction analyses were performed of the bullseye are prior to and post compaction.
The results are shown in Table a. A sample of the bullseye fines were sent to a lab to be used
as the reference standard. The results exceeded the requirement of 1.8 g/cm3 for soil
compaction.
Lab
Standard smpl1 smpl2 avg smpl1 smpl2 smpl3 avg
Moisture 0.10% 6.60% 7.40% 7.00% 7.0% 7.0% 6.40% 6.8%
Wet Density (gr/cm3)2.124038 1.811679 1.8917711 1.85172512 2.4396 2.490859 2.417174 2.449211
Dry Density (gr/cm3)NA 1.69955 1.7620222 1.73078633 2.279416 2.327471 2.271407 2.3
Densisty relative to Std 80% 83% 81% 107% 110% 107% 108%
Post Compaction Field Analysis
Pre-Compaction Field Analysis
Bullseye Grading & Leveling:
The grade of the bullseye area of the VTVL was measured after operations and was found to
be within the requirements for the project.
PHASE 3 – PISCES rover emplaces pavers using KSC PDM
8. VTVL pad surface: Tele-robotic emplacement of basalt interlocking pavers in
“Bulls Eye” (3m x 3m) central landing location.
Figure 7. Paver Deployment Mechanism (PDM) on PISCES Planetary Rover
PHASE 4 – PISCES rover/roller compact outer apron
9. VTVL pad apron: Tele-robotic grading, leveling and compaction of VTVL pad
outer apron
VTVL pad apron: Tele-robotic grading, leveling and compaction of VTVL pad outer apron.
During this stage the PDM payload was removed from the rover and replaced with the heavy
leveling blade. The rover was used again to complete the grading and leveling of the Apron
area surrounding the bullseye.
.
Figure 8. Outer apron area after being graded & leveled.
PHASE 5 - Rover places/levels additional gravel on apron
10. VTVL pad apron: Tele-robotic emplacement of gravel
Figure 9. Final VTVL pad bullseye and gravel covered Apron.
PHASE 6: VTVL Pad Rocket Engine Verification Testing
11. VTVL Vehicle Rocket Thrust Testing: Test stand emplacement
The rocket selected for the hot fire test is a Class M solid propellant engine model RMS-
98/15360 (N3300) manufactured by Aerotech. The engine has 940 lbs of trust and a total
impulse of 13,410 Ns-1 with a 4s burn time. This thrust level matches some of the
commercially available VTVL landers that are flying today at terrestrial locations.
The test will be a stationary test with the engine mounted on a fixed test stand (figure 10)
and the nozzle placed 0.45 to 0.5m above the center paver. The objective of the test is to
verify that the basalt pavers maintain structural integrity throughout the engine firing. In
addition high speed and infra-red video data and other instrumentation will confirm that
the gas flow path at the paver joints does not create any adverse effects to the VTVL
bullseye pad system.
Figure 10. Hot Fire Test Stand Design Concept
12. Simulated Rocket Engine “Hot Fire” Validation Test:
A static rocket engine firing of a Class-M, 1000 lb solid-propellant motor is planned for
March 2016 in Hawaii to validate and test the performance of the ACME basalt VTVL pad.
Results of this performance test will be published at a later date.
BASALT PAVER PRODUCTION
Pavers were designed for the 3 meter-by-3 meter VTVL bulls-eye stabilized surface such that
they would interlock and be thick enough to provide adequate compression strength. The pavers
were constructed from sub-150µm basalt fines, with no additives. For the final paver design, one
hundred (100) pavers would need to be fabricated to accommodate the VTVL bulls-eye.
Figure 11. High Temperature Basalt Paver Fabrication in Kiln
Paver production was a complicated task, turning out to be more of an “Art” in defining the
proper thermal profile, particle sizes, and mold design for thoroughly sintering the basalt without
creating cracks/breakage in the pavers. The
spring/summer 2015 timeframe saw a steep
learning curve in designing a thermal profile that
would create a suitable basalt paver. The resultant
thermal profile was an approximately 30-hour run
time in a high temperature kiln, with a maximum
sintering temperature of 2,100°F. Early paver
prototypes consistently failed in the same manner
and revealed lateral stress areas where the pavers
were pulling against the molds upon thermal
contraction of the paver. These failures were
resolved by making part of the molds “float” such
that the molds would slip upon paver contraction.
Prior to making the molds float, only about 10% of
the pavers were intact by the end of the run-time. Figure 12. Failed Paver
Figure 13. Floating mold
The post-modification intact rates improved to 50%, but revealed secondary stresses that
accounted for the remaining failures. These secondary
failures were due to vertical stress from the pavers
contracting and pulling against the ledges of the mold.
Due to the geometric constraints of the molds, and
additional floating modifications were not feasible. To
reduce vertical contraction, the sub-150µm basalt fines
were mixed with #4 basalt sand. Various mix-ratios were
tried and a 50% sand/fine ratio was found to offer the
best performance with minimal shrinkage and overall
failure rates dropped to less than 10%. The overall profile
was finalized in September 2015 at which time paver
production started in October 2015 and completed in
Figure 14. Vertical stress fractures December 2015.
Figure 15. Basalt paver production issue with hot spots and cracking during April/May
2015 – Problems resolved later in August 2015
CONCLUSION
This collaboration was between a team led by PISCES and NASA Kennedy Space Center
Swamp Works and also included contributions from Honeybee Robotics, inc, Argo, inc
(Canada), and the County of Hawaii.
A prototype VTVL pad using only in-situ basalt materials found at the analogous test site on the
Big Island of Hawaii was successfully constructed using a tele-operated robot with various
implements. Tele-operations were proven to be feasible via internet communications from
NASA Kennedy Space Center Swamp Works in Florida to Hilo, Hawaii. One hundred sintered
basalt interlocking pavers were fabricated and assembled with a robot arm and a custom gripper
system to form a bullseye central landing pad area (3m x 3m) for repeatable VTVL operations
without significant rocket plume impingement surface erosion or ejecta. The outer apron up to a
diameter of 20 m was covered with gravel using a tele-operated bull dozer blade implement. The
gravel will suffice for off-nominal landings but will not have the life cycle of the bullseye pad
area. With surface navigation beacons on the pad and thrust vectoring on the vehicle , repeatable
landings should be possible on the bullseye.
PISCES began integration and test operations in the field in late October 2015 and successfully
completed robotic construction operations in late December 2015. A static hot fire test to
simulate an approximately 4,448 N thrust VTVL lander will proceed in the spring of 2016 to
validate the construction methods by testing VTVL pad performance under solid rocket
propellant hot gas plume impingement conditions.
ACKNOWLEDGEMENTS
The authors would like to extend a big “Mahalo” to the state and county of Hawaii and the
people of the Big Island for their vision and support in executing this project. We would like to
thank the NASA Space technology Mission Directorate, Game Changing Division for providing
funding and strategic direction, and NASA Kennedy Space Center and Marshall Space flight
Center management for being supportive of the KSC Swamp Works. Many thanks also to
Honeybee Robotics, inc. and Argo inc. for their invaluable assistance.
REFERENCES:
Metzger, P. T., Lane, J. E., Kasparis,T., Jones, W. L., (2014), “Apollo Video Photogrammetry
Estimation of Plume Impingement Effects”, Icarus (Impact Factor: 3.04). 01/2014; 214(1):46–
52. DOI: 10.1016/j.icarus.2011.04.018
Sengupta, S., Mehta, M., Vizcaino, J., Metzger, P. T., (2014), “Plume Impingement Induced
Surface Erosion During Retro-Propulsive Landings on Mars” 11th International Planetary Probe
Workshop (2014).
