AIAA 2009-4961
45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit
2 - 5 August 2009, Denver, Colorado
AIAA 2009-4961
Atmospheric Mining in the Outer Solar System:
Mining Design Issues and Considerations
Bryan Palaszewski
NASA John H. Glenn Research Center
Lewis Field
MS 5-10
Cleveland, OH 44135
(216) 977-7493 Voice
(216) 433-5802 FAX
[email protected]
Fuels and Space Propellants Web Site:
http://www.grc.nasa.gov/WWW/Fuels-And-Space-Propellants/foctopsb.htm
Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy
propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and
Neptune and either returned to Earth or used in-situ for energy production. A series of university design studies were undertaken
to investigate aspects of atmospheric mining in the outer solar system. Helium 3 and hydrogen were the primary gases of interest
with hydrogen being the primary propellant for nuclear thermal or nuclear fusion rocket-based atmospheric flight. Four teams
addressed issues associated with atmospheric cruiser-based and balloon-based mining vehicles. One additional team focused on
mining of an outer planet moon for helium 3 and hydrogen. Additional supporting analyses were conducted to illuminate vehicle
sizing and orbital transportation issues.
Nomenclature
3He
4He
CWRU
delta-V
GTOW
H2
He
IEC
ISRU
Isp
K
kWe
LEO
MAE
MT
MWe
NEP
NTP
NTR
O2
PPB
STO
Helium 3
Helium (or Helium 4)
Case Western Reserve University (Cleveland, OH)
Change in velocity (km/s)
Gross Takeoff Weight
Hydrogen
Helium 4
Inertial-Electrostatic Confinement (related to nuclear fusion)
In Situ Resource Utilization
Specific Impulse (s)
Kelvin
Kilowatts of electric power
Low Earth Orbit
Mechanical and Aerospace Engineering
Metric tons
Megawatt electric (power level)
Nuclear Electric Propulsion
Nuclear Thermal Propulsion
Nuclear Thermal Rocket
Oxygen
Parts per billion
Surface to Orbit
________________________________________________________________________
* Leader of Advanced Fuels, AIAA Associate Fellow
1
This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.
AIAA 2009-4961
I.
Atmospheric Mining in the Outer Solar System
Atmospheric mining of the outer solar system (AMOSS) is one of the options for creating nuclear fuels, such as 3He, for
future fusion powered exploration vehicles or powering reactors for Earth’s planetary energy. Uranus’ and Neptune’s
atmospheres would be the primary mining sites, and robotic vehicles would wrest these gases from the hydrogen-helium gases of
those planets. While preliminary estimates of the masses of the mining vehicles have been created (Refs. 1-4), additional
supporting vehicles may enhance the mining scenarios. Storing the mined gases at automated bases on outer planet moons was
conceived to ease the storage requirements on interplanetary transfer vehicles (that would return the cryogenic gases to Earth).
There are vast reserves of potential fuels and propellants in the outer planets (Ref. 1). While the idea of mining outer planet
atmospheres is indeed enticing, the challenges to designing mining vehicles may be somewhat daunting. While past studies
related to the Daedalus Project (Ref. 5) have assumed the used of fusion propulsion for the aerostat and aerospacecraft that mines
the atmosphere and carries the fuel to Jupiter’s orbit, nuclear thermal rockets may also allow a more near term propulsion option.
While the mass of the NTP options will, in most cases, be higher than the fusion powered options, the more near term NTP vehicle
may still be attractive.
II.
University AMOSS Design Studies
An assessment of the complexity of and estimates of the masses of the transportation elements for outer planet moon
bases were conducted. Five university teams from Case Western Reserve University (CWRU) Department of Mechanical and
Aerospace Engineering (led by their professor, Dr. Jackie Sung) participated in a design study of outer planet atmospheric mining.
Four teams addressed issues associated with atmospheric cruiser-based and balloon-based mining vehicles. One additional team
focused on mining of an outer planet moon for helium 3 and hydrogen. Additional supporting analyses were conducted to
illuminate vehicle sizing and orbital transportation issues. Appendix A provides the list the student team members and Appendix
B provides some guidance for future studies.
A. Uranus, Team 1 (named Helium-3 Uranus Retrieval Nuclear Air-Breathing (HURNAB))
The HURNAB team created a detailed conceptual design of a craft to extract the helium-3 isotope from the atmosphere of
Uranus. A theoretical inertial-electrostatic confinement (IEC) nuclear fusion reactor was utilized for propulsion, operating as an
air-breathing engine during cruise in the atmosphere and operating on stored liquid hydrogen as propellant during ascent out of the
atmosphere to a target 5000 km altitude orbit. An extraction system design used a system of cryocoolers and shell-and-tube heat
exchangers to condense and extract hydrogen and helium-4 from inflowing atmospheric gas and stores gaseous helium-3 for use as
fuel and cargo for return to earth. The craft utilizes waste helium-4 as an insulator in the helium-3 storage vessel and stored the
liquid hydrogen created during the separation process as propellant. The QED engine concept (Ref. 6 to 9) provided both high
thrust and high specific impulse, requiring a relatively small amount of propellant to reach the target orbit. A total in-atmosphere
mission length of approximately 28.3 days is required to refine 500 kg helium-3 for storage and for use as fuel during cruise and
atmospheric exit.
The overall vehicle design is shown in Figure 1. The design was inspired by the X-33 / Venture Star single stage to orbit
(SSTO) demonstrator design (Ref. 10). The overall vehicle dry mass including the 500 kg payload was approximately 40,000 kg.
The overall mass of the vehicle was estimate based on past vehicle designs and estimates of the QED engine mass from Refs. 6 to
9. The overall mission delta-V to climb from the mining altitude in the atmosphere to the 5000 km orbital altitude was 16.23 km/s.
To reduce gravity losses, the initial thrust to weight of the overall vehicle was fixed at 2.0. The engine Isp was approximately
6000 s, and the propellant mass needed to reach orbit was 12,736 kg. Figures 2 provide the thrust delivered as a function of power
and mass flow rate. Figure 3 provide the propellant mass needed as a function of power and mass flow rate. Reference 11
provided the basis for the atmospheric mining and gas separation methodology.
Team 1 conclusions - It was apparent that any mining mission to Uranus will be an enormous undertaking in both
financial and scientific terms. This conceptual design rests upon overcoming several scientific barriers, primarily the development
of a working QED fusion reactor, as well as the development of fusion as an energy source. Currently, the IEC containment
method has only been proven to work in small-scale experimental tests (Refs. 6 to 9), and therefore much work must be completed
until a viable fusion engine can become a reality. There are additional material constraints such as the need for heat shielding such
as a metallic thermal protection system (TPS) capable of repeated atmospheric entries without the need for maintenance. Finally,
autonomous systems capable of controlling such a craft would be difficult to implement, as a largely independent vehicle would
likely be necessary to adequately complete the mission requirements. However, progress is being made towards achieving these
goals, and with time they may prove to be surmountable. Assuming that the technological barriers can be overcome, the
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conceptual design presented here may be an excellent choice for an intensive mining mission. The craft design is amenable to not
only a mining mission, but could easily be fitted with equipment for other missions such as planetary exploration (potentially in
conjunction with atmospheric mining) as well as a viable Earth-based single stage to orbit (SSTO) system.
Figure 1. Fusion powered cruiser (CWRU MAE Aerospace Design Project, 2008, Team 1).
Figure 2: Fusion Powered AMOSS Cruiser Thrust versus Power and Mass Flow Rate
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Figure 3: Fusion Powered AMOSS Cruiser Propellant Mass versus Power and Mass Flow Rate
B. Neptune, Team 2 (named Helium 3 Mining on Neptune for Atmospheric Mining of the Outer Solar System with a
Nuclear Thermal Propulsion System (HANS) )
An analysis was done to investigate the feasibility of a mission to mine Helium-3 from the atmosphere of Neptune. The
analysis is concerned with three phases: collection and extraction, transfer and storage. Initially, four methods of collection are
compared: a hypersonic scooper, an atmospheric cruiser, a space elevator, and an aerostat (balloon). From this set, two vehicles
were found to have the highest possible feasibility: the cruiser and the aerostat (balloon). An extraction system is designed and
analyzed for both collection vehicles. A transfer vehicle and a storage vessel are designed and their flight mechanics and orbital
transfers and rendezvous are analyzed. Each collection vehicle uses the same transfer vehicle and storage vessel. The mission
using the aerostat was found to have the highest feasibility and mass efficiency. The cruiser is found to be feasible, but at a higher
overall mass than the aerostat (balloon) option.
The mining vehicle used NTP rockets at 900 s specific impulse. A mass summary of the cruiser vehicle is provided in Table I.
Table II shows the masses of the aerostat system. References 12 to 16 proved several design points for the remaining systems in
the design team’s work.
Cruiser Subsystem
Structure
Propulsion
Tankage (3He, H2)
Total
Mass (kg)
44,676
11,900
215,369
271,945
Table I. Mass summary for cruiser (Team 2)
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Fuel Needs
In atmosphere
In space
Space Shuttle*
Drag (kN)
568
0
V (m/s)
325
17,000
Number of engines
2
2
Maximum
acceleration
4g
4g
Total mass flow rate
(MFR, kg/s)
800
800
Ve (km/s)
4.2
9.75
4.4
MFR per engine
400
400
450
Isp (s)
377
874
394
Fuel mass (kg)
5,515
105,425
250,000
Table II. Mass summary for aerostat (balloon) and orbital delivery vehicle (ferry)
Aerostat
Cruiser
Mass (kg)
19,362
271,954
Extraction Power
Consumption (kW)
5,271
2,903
Overall Volume (m3)
227,146
15,761
Maximum dimension (m)
37 (height)
50 (length)
H2 fuel required
Minimal
~ 500,000
kg/day
He-3 Processing Rate (kg/s)
6x10-6 maximum
6x10-6
changeable
Ease of Payload Transfer
Difficult (hovering, Easy (match
forward velocity = speeds)
0 m/s)
Table III. Mass summary comparison for aerostat and cruiser
Team 2 Conclusions - Feasibility: The cruiser is only feasible if an air-breathing propulsion system is used. The amount
of fuel it takes to only provide thrust, not even considering generating power for the extraction process, is prohibitively large. The
aerostat is more promising than the stand alone cruiser. Its main advantage is that is does not have to store hydrogen onboard at all.
It is also more efficient in that it uses its waste products. Its waste heat and hydrogen are used for buoyancy and the Helium 4, for
course correction thrust.
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If the assumption that the necessary technologies—in the case of the aerostat, mainly materials—are available at the time
such a mission is to be carried out, such a mission is plausible. To further increase the productivity, such a mission can easily be
scaled up to include a greater number of aerostat collection vehicles and, if necessary, additional storage vessels. In the case of the
cruiser, such a mission can be successful if an air-breathing propulsion system is used or other, better performing propulsion
systems are available at the time of mission execution
.
Figure 4. Team 2 AMOSS Aerostat-Balloon and Delivery Vehicle Scenario
Figure 5. Aerostat Operations, hovering near aerostat (CWRU MAE Aerospace Design Project, 2008, Team 2).
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C. Uranus, Team 4 (Helium Extraction from Uranus (HEXUR))
This project outlined a possible design to extract Helium 3 from the atmosphere of Uranus. Helium 3 is a valuable
resource that may one day be used to supply much of the planet’s power needs. Unfortunately, this particular isotope of Helium is
not found in any large quantity on Earth. A vehicle was designed to enter the atmosphere of Uranus and cruise at a steady altitude
while extracting Helium 3 from the atmosphere. The vehicle would then be able to supply the necessary thrust (and delta-V) to
enter an orbit where a space station would store Helium 3 for later transport to earth. The vehicle used a combination of existing
and upcoming technology to try and achieve this goal. A cruiser was designed capable of performing the task. However, due to
the vehicles relative size and weight, the cruiser may not be able to maneuver well enough to withstand the unpredictable
atmosphere of Uranus. This mission will not be feasible until a highly advanced propulsion system is developed that will allow for
a less massive and more manageable aerospacecraft to be developed.
Team 4 Conclusions - Lessons Learned: The project at hand involved designing a vehicle for a foreign environment
where no craft has ever flown. The challenges inherent to this project involve a number of unknown variables. In reality, there are
many problems that won’t present themselves until the mission is actually attempted. This need to be able to adapt will require
state of the art automation. Many difficulties presented themselves during the design phase of this project. Due to the large mass
of the planet, a large delta-V value of approximately 17.5 km/s was required to enter orbit at 5000 km above the 1 bar pressure
altitude. Initial mass for final mass ratios for this delta-V were looked at for different specific impulses and are shown below.
Wing Characteristics
Nose
Cone
Max Chord
Length
Fuel Tank
(Approximate Length)
Engine
Housing
Span
Wing Type
Wing Span (m)
Max Chord Length (m)
Wing Area
(m2)
Delta
40
76
565
Figure 5. Vehicle wing sizing (CWRU MAE Aerospace Design Project, 2008, Team 4).
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Specific impulse (s)
Number of engines
Mass summary (kg)
Payload
Hydrogen tankage
Airframe
Engine
Processing
Other storage
Other systems
Total dry mass with payload
Propellant mass
Total
800
45
500
269,219
30,000
765,000
2,500
2,000
6,000
1,075,219
8,796,259
9,871,478
900
10
500
106,447
30,000
170,000
2,500
2,000
6,000
317,447
1,960,636
2,278,083
1000
4
500
66,869
30,000
68,000
2,500
2,000
6,000
175,869
871,077
1,046,946
Table IV. Mass summaries for cruiser for 3 different engine specific impulses (Team 4)
Engine Isp (s)
800
900
1000
Initial mass / final mass ratio
9.299
7.258
5.953
Table V. Cruiser initial mass to final mass ratio for 3 different engine specific impulses (Team 4)
The specific impulses above have large initial mass for final mass ratios even though they at least double the specific
impulse for a typical cryogenic oxygen /hydrogen rocket. This ratios are large is due to the fact that the required delta V is nearly
twice as large as the delta-V for Earth launch. The large ratios showed a dire need for a high performance, high Isp engine. The
references on nuclear thermal propulsion show that NTP is capable of supplying this large Isp. However, many of the engines that
where researched during the design phase had high specific impulse but relatively low thrust due to the low mass flow rate. The
team found an NTR with the proper Isp, but did not find until later that the thrust would not be sufficient. During the intermediate
design phase, an NTR was conceived with a high propellant flow rate and high Isp. Even with the newly designed engine, the
vehicle still required 12 engines to achieve a reasonable thrust to weight ratio. The mass of the vehicle is possibly the most
important design characteristic. However, mass estimation is difficult because of its dependence on thrust requirements, propellant
mass requirements and propellant volume requirements, which are a function of the vehicle mass. Due to the multiple iterations, it
was it difficult to implement changes late in the design phase.
Recommendations: The thought of supplying the planet with power through the mining of the outer planets is tempting.
The most important factor to the success of this mission is to have a high performance propulsion system. Currently there is little
information about Nuclear Thermal Rockets capable of powering large space craft. Until there are NTRs that can deliver specific
impulses over 1000 seconds (s) and thrusts over 2 (mega-Newton (MN), any vehicle designed will be extremely large, difficult to
maneuver and may struggle to maintain flight. A large, difficult to maneuver vehicle would struggle to maintain stability in the fast
and unpredictable wind of Uranus’ atmosphere.
The obstacle of having a cruiser that is much too massive for practical flight could be overcome by having a two vehicle
system. However, the difficulty with rendezvous in the atmosphere is more difficult to overcome than maneuvering a large aircraft.
Based on the information available and research done on Nuclear Thermal Propulsion, a mission to mine Uranus may be possible,
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but will not be feasible until a high thrust, high specific impulse engine is developed. Until then, any vehicle will be too large to
maintain stable cruising conditions.
D. Neptune, Team 5 (NAHES or Neptune Atmosphere 3He Extraction System)
This report proposes a system for the extraction of helium-3 from the atmosphere of Neptune. It was found that the power
of the rockets used will be the most important design consideration for a craft to enter Neptune’s atmosphere, collect atmosphere
and extract helium-3 through a cryo-cooling process, and then exit the atmosphere to deposit the collected helium-3 at a satellite
holding station. The thrust to weight ratio of the proposed craft was found to be 1.038, with a total mass of said craft being
2,532,918 kg. This illustrates the need to find a more powerful and efficient propulsion system. With over 2,000,000 kg of the
weight being the fuel, a more efficient system would greatly reduce the weight of the vehicle and allow for a much smaller
aerodynamic design. Currently, the cruiser would be massive and would be difficult to design a way for it to re-enter Neptune’s
atmosphere without obtaining some structural damage from the thermal and drag forces.
During the design process, the integration of a large volume hydrogen tank with an aerodynamic vehicle became a critical
issue (Figure 6). Many discussions were held to reconfigure the cruiser late in the design process. Realization of the hydrogen
tank size with simple first estimates will be a powerful tool for future mission studies.
Mass Properties Table
Subcomponents
Subcomponent
mass (kg)
Heat Exchangers
Total masses
(kg)
2,000
Heat exchanger (HE) #1
HE #2
HE #3
HE #4
External HE
Piping, shells, misc. systems
76
400
67
212
166
1079
Structure
505,035
Cruiser Body (minus heat
exchangers)
71,346
Propellant Tank
81,035
3He Tank (full)
654
NHEX-P (x10)
35,000
Compressors
2,000
Propellant
Total Cruiser Mass (Full propellant
and 3He payload)
2,025,883
2,532,918
Table VI. Cruiser mass summary (Team 5)
Team 5 Conclusions - From all the research conducted on this project, it has been made abundantly clear that rocket
power is a very important design consideration. Without very powerful, efficient and low mass rockets, this mission is completely
unfeasible. The proposed are NHEX-P rockets able to get the job done in theory, but just barely. The largest concern with these
rockets was the mass. 35,000 kg was suggested as the mass for the rockets based on several NTRs that were examined and scaled
up, obviously. It seemed like a reasonable mass, taking into account the shielding, the core, the nozzle, and any other subsystems,
but it was really just a shot in the dark. The actual mass of such a system could be twice that mass, or half that mass.
Unfortunately, a much more exact mass estimate was not possible given the knowledge base and experience of the researchers.
Future work towards a helium-3 extraction mission to Neptune should focus heavily on the propulsion system. The rockets
need to have very high thrust, very high Isp, and be relatively low weight. The NHEX-P rockets proposed in this paper have a very
high Isp and thrust, but they are also very massive. Each additional rocket adds a sizable 2580 kN of thrust, but adds an additional
35,000 kg of structure mass and 140,000 kg of propellant at an 80% fuel mass ratio. Designing a lighter and more powerful NTR is
an absolute must for a mission of this type to succeed. Along with improving the propulsion system, designing a cruiser using
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lightweight and strong materials would help to reduce the weight, however, the mass of the fuel is so great that any structural
changes would not make much of a difference. Improving the airfoil design would help by reducing the size of the wings allow for
a much more aerodynamic vehicle. This would help to reduce and stresses that would occur during re-entry.
Figure 6. Cruiser and hydrogen tank integration issues (CWRU MAE Aerospace Design Project, 2008, Team 5).
E. Uranus Moon, Sycorax, Team 3 (Tempest Mining System)
Our team’s assignment was to examine the feasibility of harvesting helum-3 from one of Uranus’s moons and to design a
conceptual system capable of mining the chosen moon. Such a system needed to be capable of mining and purifying 500 kg of
helium-3 and delivering it to orbit for pickup and return to Earth for utilization in earth-based fusion reactors. Of Uranus’s moons,
we chose Sycorax as our final target because it is the largest moon that is outside of Uranus’ magnetic field.
The system we developed consists of five legged mining vehicles, with moderate on-board regolith processing capability, tethered
to a large central base station which provides electrical power to the mining vehicles and performs the remainder of the helium-3
purification. The system also includes a storage satellite in orbit where the helium-3 is held for pickup, and a surface to orbit
vehicle to transfer the helium-3 from the base station to the storage satellite. The minimum mining rate of the design is 500 kg of
purified helium-3 per year. The total combined mass of all system components that must be landed on Sycorax is 537,000 kg, and
the operating power requirements are 9.8 megawatts, to be provided by the central base station’s reactor.
The moon data was gathered from astronomical observations (Ref. 17) and the moon was assumed to be 60% water ice and 40%
rocky material. The vehicle design included a lander for several mining vehicles, a power system, and an ascent vehicle to bring
the 3He to an escape orbit. Several miners were used to reduce the time for acquiring the 3He.
Team 3 Conclusions - Summary and Lessons Learned: The final mining system as designed accomplishes the main
mission objective—the collection of 500 kg of helium-3 per year—and does so with reasonable energy consumption and mass
requirements as evidenced by the data shown in tables 6-8. Throughout the analysis some assumptions where made that allowed
our team to move forward with the analysis, the biggest of those being the assumptions concerning the moon Sycorax. It should be
noted that much of the data regarding Sycorax is speculative and thus this data would have a significant impact on the current
design of the system if altered. During the course of the project, our team has come to a better understanding of the design
process, how precedent (as in existing designs) is a large determinant of design choices and how innovation within the design
process often happens on small, manageable scales.
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Figure 7. Moon mining vehicle (CWRU MAE Aerospace Design Project, 2008, Team 3).
Name of Component
Estimated Mass (kg)
STO (Loaded)
9,000
9.765 MW reactor
105,462
5 spare He-3 storage tanks
12,500
5 X Mining Walkers
150,000
30 km X 5 cabling
61,200
Central Station Structure
20,000
Total Mass with 1.5 safety factor
537,243
Table VII. Moon mining system mass summary (Team 3)
Table VIII. Moon mining power system mass summary versus 3He concentration (Team 3)
Recommendations and Future Work: Given the technology assumption for the the mission, the system designed was
conservative and easily transferable to other moons if the need arises; thus we believe that the mission is not only feasible with our
designed system but practical as well. However, to narrow the mission statement and perhaps better facilitate the design process,
more information should be provided, such as the interplanetary vehicle arrival intervals, and the availability of and permissibility
of use of certain future technologies. Future work would involve gathering necessary robotic probe data on moons such as
Sycorax. Additional robotic mission data would allow for a more accurate analysis and design process; with that data, many fewer
assumptions would have to be made about the moon’s composition and orbital properties.
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III. Concluding Remarks
Five university teams created outer planet atmosphere and moon mining vehicle designs. In several cases, very good initial
designs were created for the atmospheric flight vehicles. Using nuclear thermal propulsion, effective flights could be conducted
into and out of Uranus’ and Neptune’s atmosphere. One team chose a fusion powered rocket for the cruiser and this resulted in a
very compact and lightweight vehicle. Outer planet moon mining vehicles were also designed and parametric influences of 3He
concentration were made. Multiple miners were supplied from a central power system, making the mobile miners lighter in weight
than a miner with on-board power. Some teams concluded that nuclear thermal propulsion must focus on higher Isp options,
strive for high thrust to weight engines, and /or await the availability of very high Isp fusion powered vehicles. Based on these
analyses, there will likely be several possible future avenues for effectively using the gases of the outer planets for exciting
exploration missions. When focusing on Uranus and Neptune, these planets offer vast reservoirs of fuels and with the advent of
nuclear fusion propulsion, may offer us the best option for the first practical interstellar flight.
IV. References
1)
Palaszewski, B., “Atmospheric Mining in the Outer Solar System: Orbital Transfer Vehicles and Outer Planet Moon Base
Options,” AIAA 2008-4861, July 2008.
2)
Palaszewski, B., “Atmospheric Mining In The Outer Solar System: Mission Scenarios and Options For In-Situ Resource
Utilization.” AIAA 2007-5598, July 2007.
3)
Palaszewski, B., “Atmospheric Mining In The Outer Solar System: Vehicle Sizing Issues.” AIAA 2006-5222, July 2006.
4)
Palaszewski, B., ”Atmospheric Mining in the Outer Solar System,” AIAA 2005-4319, July 2005.
5)
Parkinson, R. C., “Project Daedalus Propellant Acquisition Techniques,” Journal of the British Interplanetary Society
(JBIS) Interstellar Studies , Supplement, Final Report of the BIS Starship Study, 1978.
6)
Bussard, R., “ASPEN II: Two-Staging and Radiation Shielding Effects on ASPEN Vehicle Performance,” LA-26-80,
6/25/62, declassified w/deletions on 09/06/67; and in “ASPEN: Nuclear Propulsion for Earth-to-Orbit Aerospace Plane Vehicles,”
Robert W. Bussard, Proceedings International Conference on Spaceflight, Rome, Italy, June 1971.
7)
Bussard, R.W. , “The QED Engine System: Direct-Electric Fusion-Powered Rocket Propulsion Systems.” 1993. Vol. AIP
Conference Proceedings 271, pp. 1601-1612.
8)
Bussard, R.W. and Jameson, L.W. , “The QED Engine Spectrum: Fusion-Electric Propulsion for Air-Breathing to
Interstellar Flight,” Journal of Propulsion and Power, 1995, Vol. 11, pp. 365-372.
9)
Miley, G.H., et al., “Issues for Development of Inertial Electrostatic Confinement (IEC) for Future Fusion Propulsion,”
AIAA-1999-2140, 35th AIAA Joint Propulsion Conference, Los Angeles, CA, 1999.
10)
Scott A. Berry, Thomas J. Horvath, Brian R. Hollis, Richard A. Thompson, and H. Harris Hamilton II, “X-33 Hypersonic
Boundary Layer Transition,” AIAA 99-3560, 33rd AIAA Thermophysics Conference, Norfolk, VA, June 28 - July 1, 1999.
11)
Paniagua, J., Powel, J., Maise, G., ”A Cost Effective Space Infrastructure for Retrieval of Helium-3 from Uranus for
Earth-based Fusion Power Systems Utilizing MITEE Nuclear Propulsion System,“ Plus Ultra Technologies, Inc., Report number
PUR-11, July 23, 1999, available at: http://www.newworlds.com/reports/PUR-11.PDF
12)
Dunn, Bruce P.,. “High-Energy Orbit Refueling for Orbital Transfer Vehicles,” Journal of Spacecraft and Rockets
Volume. 24, No. 6, 1987, pp. 518-522.
13)
Noca, M.; Polk, J. E. “Ion Thrusters And LFAs For Outer Planet Exploration,“ AAAF 6th International Symposium;
Versailles; France, May 2002.
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14)
Hunt, James L., Laruelle, Gerard, Wagner, Alain, “Systems Challenges for Hypersonic Vehicles;” AGARD Interpanel
Symposium on Future Aerospace Technology in Service to the Alliance, NASA-TM-112908, AGARD-Paper-C37, 1997.
15)
Starr, Brett R.; Westhelle, Carlos H.; Masciarelli, James P., “Aerocapture Performance Analysis For A Neptune-Triton
Exploration Mission,” NASA/TM-2006-214300, April 2006.
16)
Stanley K. Borowski, Leonard A. Dudzinski, Melissa L. McGuire, “Vehicle and Mission Design Options for the Human
Exploration of Mars/Phobos Using “Bimodal” NTR and LANTR Propulsion, AIAA–98–3883NASA/TM—1998-208834/REV1,
December 2002.
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Hussmann, Hauke; Sohl, Frank; Spohn, Tilman, “Subsurface oceans and deep interiors of medium-sized outer planet
satellites and large trans-neptunian objects”, Icarus, Volume 185, Issue 1, p. 258-273.
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Appendix A: University Team Members: CWRU, Spring 2008
Dr. Jackie Sung, CWRU Mechanical and Aerospace Engineering (MAE) Professor and Design Project Advisor)
Team 1: HURNAB: Helium-3 Uranus Retrieval Nuclear Air-Breathing Cruiser
Kyle Brady
Kyle Niemeyer
Loretta Pasket
Team 2: Team HANS - Helium-3 Mining on Neptune: Atmospheric Mining of Outer Solar System using a Nuclear Propulsion
System
C.J. Huang
Jason McGloin
Sam Salinas
Leah Struchen
Team 3: Tempest Mining System
Michael Giacoma
Michael Orth
Nicholas Young
Edward Hunter
Team 4: Helium Extraction from Uranus (HEXUR)
Neal Duryea
Andrew Renckly
Mark Ruffing
Team 5: NAHES – Neptune Atmosphere Helium-3 Extraction System
Anthony Falter
Ryan Kurtanich
Devon Parker
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Appendix B. Supporting analyses and observations
In addition to the university team studies, reviews of outer planet spacecraft design issues were initiated. A list of the
issues addressed is noted below:
Mission planning.
Cryogenic fuel storage issues.
Cryogenic dust (outer planet moons, ice migration).
Drilling into ice, walkers on ice-dust surfaces.
Possible power generation using electro dynamic tethers (EDT), cutting across the outer planet magnetic field lines.
Global Positioning System (GPS) vehicles in outer planet orbits for navigation.
Observational satellite for outer planet weather monitoring, diverting cruisers from harm.
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Figure B1. Outer planet moon densities (Ref. xx, Hussmann, Hauke; Sohl, Frank; Spohn, Tilman, Subsurface oceans and deep
interiors of medium-sized outer planet satellites and large trans-neptunian objects, Icarus, Volume 185, Issue 1, p. 258-273)
Moon Bases in Cryogenic
Environments: Issues
•
•
•
•
•
•
•
•
Power sources
Seals
Rotating components
Adhesives
Flexible – inflatable surfaces
Dust, ice characteristics
Robots, for maintenance, etc.
Warmth for, maintenance of astronauts
Figure B2. Issues for cryogenic outer planet moon surface operations (Revolutionary Aerospace Concepts (RASC), Human Outer
Planet Exploration (HOPE) study).
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Atmosphere of Uranus:
K.A. Rages, H.B. Hammel, A.J. Friedson,
Evidence for temporal change at Uranus’ south pole, 2004
•
•
•
Flight in the outer planet
atmospheres are based
on flight at altitudes
where the atmospheric
pressure is about 1
atmosphere.
The charts notes that this
altitude implies flying in
the haze layer of Uranus.
The issue of flight in the
haze layer should be
investigated (effects on
aerospacecraft, mining
efficiency , etc.).
Figure B3. Uranus atmospheric structure, haze phenomena (Ref. xx, K.A. Rages a,b, , H.B. Hammel c, A.J. Friedsond,
“Evidence for temporal change at Uranus’ south pole,” Icarus 172 (2004) pp. 548–554).
AMOSS: What’s Next?
•
Daedalus Redux (British Interplanetary Society (BIS) Study, Martin, A.,
et al., 1979).
– More attention to atmospheric mining for starship fueling.
• Schedules of ISRU fuel deliveries.
– Effect on construction – if ISRU process slowed or speeded up?
• Daedalus study assumed fusion powered atmospheric transfer
vehicles and aerostats for gathering helium 3 and deuterium
from Jupiter’s atmosphere.
– Move mining location to Uranus or Neptune.
– Recent studies of AMOSS (Palaszewski, et al. AIAA JPC
2005, 2006, 2007, 2008) have used nuclear thermal
propulsion (NTP) aerospacecraft (cruiser aircraft) for fuel
mining and orbital delivery.
– Is NTP effective as a propulsion option? Is fusion
required?
– Development of micro-factories (or macro-factories, or nanofactories(?)) for ship assembly and non-fuel related construction.
• Time added for nano- or micro-factory versus macro-factory
construction (time for assembling atoms and molecules,
literally…)
Figure B4. Atmospheric mining issues
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