Bryan Palaszewski

Glenn Research Center, Cleveland, Ohio

Solar System Exploration Augmented by 

Lunar and Outer Planet Resource Utilization: 

Historical Perspectives and Future Possibilities

NASA/TM—2014-218136

September 2014

AIAA–2014–0498
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Bryan Palaszewski

Glenn Research Center, Cleveland, Ohio

Solar System Exploration Augmented by 

Lunar and Outer Planet Resource Utilization: 

Historical Perspectives and Future Possibilities

NASA/TM—2014-218136

September 2014

AIAA–2014–0498

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135

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NASA/TM—2014-218136 1

Solar System Exploration Augmented by

Lunar and Outer Planet Resource Utilization: 

Historical Perspectives and Future Possibilities

Bryan Palaszewski

National Aeronautics and Space Administration

Glenn Research Center

Cleveland, Ohio 44135

Abstract

Establishing a lunar presence and creating an industrial capability on the Moon may lead to important 

new discoveries for all of human kind. Historical studies of lunar exploration, in-situ resource utilization 

(ISRU) and industrialization all point to the vast resources on the Moon and its links to future human and 

robotic exploration. In the historical work, a broad range of technological innovations are described and 

analyzed. These studies depict program planning for future human missions throughout the solar system, 

lunar launched nuclear rockets, and future human settlements on the Moon, respectively. Updated 

analyses based on the visions presented are presented. While advanced propulsion systems were proposed 

in these historical studies, further investigation of nuclear options using high power nuclear thermal 

propulsion, nuclear surface power, as well as advanced chemical propulsion can significantly enhance 

these scenarios. 

Robotic and human outer planet exploration options are described in many detailed and extensive 

studies. Nuclear propulsion options for fast trips to the outer planets are discussed. To refuel such 

vehicles, atmospheric mining in the outer solar system has also been investigated as a means of fuel 

production for high energy propulsion and power. Fusion fuels such as helium 3 (3He) and hydrogen (H2)

can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ 

for energy production. Helium 3 and H2 (deuterium, etc.) were the primary gases of interest with 

hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based 

atmospheric flight. A series of analyses have investigated resource capturing aspects of atmospheric 

mining in the outer solar system. These analyses included the gas capturing rate, storage options, and 

different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen 

and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of 

additional exploration and exploitation vehicles exists. 

Nomenclature

3He helium 3

4He helium (or helium 4)

AMOSS atmospheric mining in the outer solar system

CC closed cycle

CH4 methane

∆V change in velocity (km/s)

GCNR gas core nuclear rocket

GCR Galactic Cosmic Rays

GTOW Gross Takeoff Weight

H2 hydrogen

He helium 4

ISRU in situ resource utilization

Isp specific impulse (s)
NASA/TM—2014-218136 2

K Kelvin

kT kilotons of explosive power

kWe kilowatts of electric power

LEO low Earth orbit

M dry, stage stage dry mass (kg) 

M, dry coefficient stage dry mass coefficient, B

M p propellant mass (kg)

MT metric tons

MWe megawatt electric (power level)

NEP Nuclear Electric Propulsion

NPP Nuclear Pulse Propulsion

NTP Nuclear Thermal Propulsion

NTR Nuclear Thermal Rocket

OC open cycle

O2 oxygen

PPB parts per billion

UAV Uninhabited Aerial Vehicle

1.0 Introduction

Human and robotic missions have been planned for targets throughout the solar system. Both types of 

missions can benefit greatly from the resources available from the planets and/or their moons. These 

benefits include water on many of the outer planet moons and large asteroids. With this water, O2/H2

rocket propulsion systems can be fueled, breathing O2 can be extracted, and other life support functions 

(cooling fluids, etc.) can be facilitated. In addition, the atmospheres of many planets have ready reserves 

of gases for propellant production. Carbon dioxide on Mars can be separated into O2 and carbon 

monoxide or CH4. The outer planets offer enormous amounts of energetic gases such as H2, 3He, CH4, 

and ammonia. By using these in-situ resources, robotic precursor missions can double or triple their 

payloads to the surface and return double or triple the samples from the solar system targets. Without insitu resource utilization (ISRU), solar system exploration will be exceedingly limited. For future large 

scale human missions, the possibilities of ISRU for of human exploration and finally settlement offer the 

best opportunities for sustainability and success. 

2.0 Human Exploration Options

In the 1950s, 1960s, 1970s, and 1980s, ambitious robotic and human mission were planned, spanning 

from Mercury to the outermost reaches of the solar system (Refs. 1 to 10). While investments in robotic 

missions have continued, human exploration of the solar system has awaited new invigorating steps. 

While lunar and Mars missions are in the early step-wise planning stages, many cost barriers have 

prevented their implementation. Future human missions to other destinations such as Mercury and Saturn 

will also require long-term investments. Currently, Mercury and Saturn have robotic missions returning 

invaluable data on those planets and their environs (Refs. 11 and 12). These data have provided insights 

that will ensure the success of future missions. With its proximity to the Sun, Mercury has extremely high 

temperatures and requires special high heat flux considerations for long-term human visits or bases. In 

contrast, temperatures at Saturn and its moons require designs for cryogenic environments. The 

possibilities for ISRU may allow more effective robotic missions and human visits to these planetary 

targets. 
NASA/TM—2014-218136 3

2.1 Mercury

Mercury is the closest planet to the Sun; ranging from a perihelion of 46 million km to an aphelion of 

nearly 70 million km. The high temperature, high heat flux environment at Mercury and the tenuous 

surface emanations of several major chemical species (sodium, etc.) surrounding it will likely pose 

challenges to long term human visits. Permanently shadowed craters offer a valuable niche for longer 

term human visits and planetary bases. Such craters offer cryogenic temperatures while the sun facing 

surface is at a temperature of 590 to 725 K. The north polar regions of Mercury have been identified as a 

likely location for such permanently shadowed craters (Refs. 11, 12, and 13). Water ice is also likely to be 

in these craters, further aiding and assisting any human explorations. Short exploratory missions can be 

accomplished with hopping ascent-descent vehicles from the base at the shadowed crater. 

Figure 1 shows the locations of the shadowed craters (Ref. 12). Figure 2 depicts the temperatures that 

would exist in and near the craters (Ref. 13). The crater could accommodate a small base or at least an 

initial landing site. The lander’s temperature could stay within the nominal operating temperatures of 

traditional spacecraft. The temperature distribution in the crater would allow construction of the base at 

the warmer side of the crater and then the frozen volatiles would be extracted with cryogenic mining 

machines. 

2.2 Saturn and Its Moons

Saturn is one of the outer planets. Its orbit has a perihelion 1,352.6 million km and an aphelion

1,514.50 million km. An extensive series of flybys of the Saturnian moons have been conducted by the 

Cassini spacecraft. During these flybys, cameras and instruments capture and data on the moons’ 

composition, atmosphere and cloud cover (on the moon Titan), volcanos, plumes, rotation, and gravity. 

Titan is the largest moon of Saturn. Its intriguing nature includes a nitrogen and CH4 atmosphere and 

a subsurface ocean (Ref. 14). Recent flybys of the Cassini spacecraft have shown direct visual evidence of 

the northern lakes which are likely composed of CH4. Based on measurements and theories of the 

evolution of Titan, a large ocean of water and ammonia may exist below the icy surface. Large lakes in 

the North Polar regions have been seen on Titan’s surface, and they are likely composed of liquid CH4. 

Figure 3 shows the possible nature of Titan’s interior, surface, and atmosphere. While CH4 can be used as 

an effective rocket propellant, its nitrogen could be used in cold gas propulsion or electric propulsion 

(resistojet, arcjet or magneto-plasma-dynamic (MPD) thrusters). 

2.3 Enceladus

The moon Enceladus is producing a large plume of water that is escaping into space. Speculation on 

the production of that water varies. The South Polar region has several hot spots (a cryogenic, volcanic 

area), known as the tiger stripes, matching the location of the plume of water exiting Enceladus (Ref. 15). 

In-situ resources from the Titan water ocean can be used for rocket propellants. Access to the ocean 

may only require drilling a short (or km long) distance into the icy crust. At Enceladus, the water plume 

may be captured, or the ocean of reservoir feeding the plume will be tapped. Capturing this water may

prove difficult, however, and additional research is needed to find the best manner of fluid capturing. 

2.4 Asteroids

An excellent additional target may be Ceres, the largest asteroid in our solar system. Ceres may 

provide substantial water from its water ice and the potential ocean below the ice (Ref. 16). As with 

Enceladus, drilling through many km of ice may be required and finding sufficiently deep crevasses will 

no doubt be useful in easing the drilling requirements. 
NASA/TM—2014-218136 4

3.0 Mission Studies

3.1 Mercury Missions

A human round trip mission to Mercury was assessed. The mission ∆V values for the round trip 

Mercury missions were derived from References 17 to 20. The highest ∆V case was selected from this 

data: an Earth departure ∆V of 5.2 km/s, a Mercury arrival ∆V of 10.9 km/s and a Mercury departure ∆V

of 8.7 km/s (Ref. 17). Each ∆V was delivered by a separate single stage; thus a three stage vehicle is used.

At Earth, a capsule enters the atmosphere to return the crew directly to Earth. The capsule’s mass is 

4,350 kg (Ref. 17). The round trip time is 585 days with a 40 day stay time at Mercury (Ref. 15). In this 

case, the vehicle does not land on Mercury. The LEO masses of both chemical propulsion and nuclear 

thermal propulsion vehicles were estimated. Figure 4 compares the LEO masses for two types of chemical 

propulsion systems and two nuclear thermal propulsion (NTP) systems. The interplanetary chemical 

propulsion systems used tankage dry mass coefficients of 3 and 5 percent of the total propellant mass in 

the tankage. In many cases, these dry masses may be deemed to be optimistically low; however, they 

allow some relative comparison of the chemical propulsion and the nuclear mission cases. 

The NTP vehicles dry mass was 15 percent of the propellant mass (Table 1). In current NTP designs, 

an Isp of 900 sec is nominally used (Refs. 23 and 24). Somewhat lower Isp values were used for these 

missions: 800 and 850 sec, respectively. These lower Isp values were assumed given the high heat flux 

environment of Mercury and the degraded Isp values would reflect the added propellant used for 

propellant cooling and/or refrigeration. The chemical propulsion systems required between 17,150 and 

27,000 MT to accomplish the mission. The NTP vehicles required approximately an order of magnitude 

less mass in LEO: 1,700 to 2,300 MT. 

TABLE 1.—SPACE VEHICLE DRY MASS COEFFICIENT

AND ROCKET ENGINE SPECIFIC IMPULSE (Isp)

Technology Isp

(sec)

M, dry coefficient

(kg/kg M,p)

Chemical-1 450 0.03

Chemical-2 450 0.05

Chemical lander 480 0.20

NTP-1 800 0.15

NTP-2 850 0.15

Based on Reference 21, the stage and lander mass was estimated with the following mass scaling 

equation: 

M dry,stage (kg) = M, dry coefficient * M p (kg)

A Mercury landing vehicle mass was also estimated. The one-way ∆V for the lander was 3.5 km/s 

(Ref. 22). The ascent ∆V was also 3.5 km/s. These ∆V values accommodate approximately 19 percent for 

gravity losses for each maneuver; this gravity loss ∆V is added to the orbital velocity for a 100 km orbit 

which is 2.945 km/s. The lander Isp was 480 sec. The higher Isp was chosen for the lander as the engine 

used a higher engine expansion ratio that the interplanetary transfer vehicle (Ref. 21). The smaller engine 

size would allow a higher expansion ratio, given the typical volume constraints for space vehicles. The 

dry mass coefficient was 20 percent of the total propellant load. While the Mercury missions will likely 

require more aggressive thermal control (propellant shielding, cooling, etc.), that thermal control system 

mass is accommodated in the payload mass of the vehicle. The payload delivered to the surface was 

10 MT. Figure 5 compares the mass in LEO of a one-way lander and a round trip lander. The masses were 

140 MT for the round trip lander and 27 MT for the one way lander. Thus, using ISRU on the surface of 

Mercury to replenish the lander’s propellant would allow a savings of 113 MT on this mission. Additional 

analyses are needed to investigate the mass reductions for the interplanetary transfer vehicle to carry the 
NASA/TM—2014-218136 5

lander to Mercury. Another option would be to carry five landers to Mercury rather than carry simply one 

lander; many more permanently shadowed craters could then be visited on one mission. The 

interplanetary vehicle carrying the five landers could be sent on a lower energy trajectory than the human 

flights, thus saving additional mass launched into LEO in the overall Mercury architecture. 

Additional summary data on mission design is summarized in Reference 20. Figure 6 provides map of 

the one-way ∆V and trip time for a wide range of planetary targets (Ref. 20). Fast missions to Jupiter and 

Mercury are possible with ∆V values of 80 to 100 km/s. Nuclear propulsion systems may someday allow 

such ambitious missions and if augmented by ISRU, such mission will be within our technological reach

3.2 Atmospheric Mining in the Outer Solar System (AMOSS)

Atmospheric mining in the outer solar system can be a powerful ISRU tool in extracting fuels from 

the outer planets and allow fast human and robotic exploration of the solar system. Preliminary designs of 

aerospacecraft with gas core rocket nuclear engines for mining the outer planets were developed (Refs. 23

and 24). Helium 3, a nuclear fusion fuel, would be extracted from the atmosphere and stored for final 

delivery to orbital assets. Analyses showed that gas core nuclear rocket (GCNR) engines can reduce the 

mass of such aerospacecraft mining vehicles very significantly: from 72 to 80 percent reduction over 

nuclear thermal propulsion (NTP) solid core powered aerospacecraft mining vehicles. While this mass 

reduction is important in reducing the mass of the overall mining system, the complexity of a fissioning 

plasma gas core rocket is much higher than the more traditional solid core NTP engines. Additional 

analyses were conducted to calculate the capture rates of 3He H2 and 4He during the mining process. 

Very large masses of H2 and 4He are produced every day during the often lengthy process (multi-day) of 

3He capture and gas separation. Figure 7 shows the mass of H2 needed for the gas core rocket and the 

potentially excess H2 captured every day (Ref. 23). Typically, these very large (excess) additional fuel 

masses can dwarf the requirements needed for H2 captured for ascent to orbit. Thus, the potential for 

fueling small and large fleets of additional exploration and exploitation vehicles exists. Aerial vehicle 

designs can take on many configurations. Additional aerospacecraft or other uninhabited aerial vehicles 

(UAVs), or balloons, rockets, etc., could fly through the outer planet atmospheres, for global weather 

observations, localized storm or other disturbance investigations, wind speed measurements, polar 

observations, etc. Deep-diving aircraft (built with the strength to withstand many atmospheres of 

pressure) powered by the excess H2 or 4He may be designed to probe the higher density regions of the gas 

giants. 

Based on these past analyses, there will likely be several possible future avenues for effective use of 

the gases of the outer planets for exciting and scientifically important atmospheric exploration missions. 

The analyses focused on Uranus and Neptune, as these planets offer vast reservoirs of fuels that are more 

readily accessible than those from Jupiter and Saturn (as these latter planets require lower energies needed 

to attain orbit and present less danger from powerful atmospheric lightning) and, with the advent of 

nuclear fusion propulsion, may offer us the best option for fast interplanetary travel and the first practical 

interstellar flight. 

3.3 Nuclear Underground Explosions

Based on recent measurements and simulations of the lunar radiation environment, it appears that 

long term occupancy of the lunar surface may be detrimental to human beings. In addition to the long 

term exposure to natural radiation sources (galactic cosmic rays, solar flares, etc.), there is additional 

scattered radiation on the lunar surface (Ref. 25). Based on these most recent measurements and the past 

work in lunar bases, it seems reasonable to assess living and working in underground facilities on the 

Moon. Using small of large nuclear devices on the Moon may provide an option for creating a series of 

large habitable underground spaces. Project Plowshare in the 1960s (Refs. 26 to 33) addressed some of 

the issues with using nuclear devices to complete large scale redirection of rivers, building canals, and 

many other massive civil engineering projects. 
NASA/TM—2014-218136 6

Past Earth based nuclear weapons testing often was done underground due to the Nuclear Test Ban 

Treaty of 1963. The tests often left sizable craters on the surface. When a nuclear device is sufficiently 

deeply buried, the explosive force can be completely contained underground (Ref. 26, Figure 8). The blast 

vaporizes some of the surrounding rocky material which then expands and creates an underground cavity, 

as shown in Figure 8. In most cases the weight of overhead rock soon crumbles the roof of the void 

chamber and a vertical column (or chimney) is created by the successively falling loose rocky layers. The 

material in the chimney undergoes compaction after the roof collapse but the initial amount of void space 

created by the blast just after detonation is distributed in this broken rocky debris. Small robotic mining 

systems could be used to manage the debris. Based on historical data, such a space can also be spherical if 

the blast size is sufficiently small. After the radiation has fallen to acceptable levels, people could 

potentially create comfortable living spaces. 

In Reference 7, this technique was proposed for not only living spaces, but for large scale ISRU. 

Nuclear explosions would be used to melt and vaporize lunar regolith. Figure 9 illustrates four different 

processes using nuclear detonations (Ref. 7). There are two chambers: one for the nuclear explosion, and 

one for the reaction product capturing. This processing would essentially chemically reacting O2, H2, or 

other species. The processes range from creating O2 and metal oxides to producing water and metal 

carbides. From Reference 7:

“A nuclear charge of one kiloton, detonated underground, fractures approximately 80,000 cubic 

meters or 330,000 tons of lunar rock, containing 130,000 MT of oxygen. At least 1%, or 33,000 

MT, of the rock is fully evaporated. The silicon and metals condense quickly. But, since they are 

in an essentially pure oxygen atmosphere, they also reoxidize vigorously. Estimating, very 

conservatively, that only 20 to 30% of the liberated oxygen can be extracted and stored, this 

means that through the underground detonation of a one-kiloton nuclear charge, of a systems 

mass of a few hundred pounds, 6,000 to 10,000 MT (Earth weight) of oxygen can be provided. ”

Certainly, extensive processing will require maintenance of the nearly spherical cavities and effective 

pumping schemes to introduce the gases into the underground chambers for the planned reactions. 

However the rates of production may be high enough to warrant the use of nuclear detonations. 

3.4 Lunar Slide Lander

The lunar slide lander uses friction between a descending tubular spacecraft and a prepared runway of 

lunar regolith. The operations of the slide lander are in eight phases (Ref. 8): 

1. Elliptical orbit descent. 

2. Perilune maneuver (pre-landing retro-thrust). 

3. Approach to touchdown (cut in supporting (vertical) thrust at the end of Phase 3). 

4. Touchdown with harenodynamic tail brake. A positive angle of attack is maintained by the 

supporting thrust. 

5. Initiation of main drag phase. Touchdown of harenodynamic side brakes. 

6. Main drag slide phase with supporting thrust. 

7. Main drag slide phase without supporting thrust. 

8. Final braking by means of additional braking devices, or brief retro-thrust, for a controlled stop. 

The slide lander was an attempt to reduce the total propellant load required for lunar landings. While 

the approach velocity of the lander is over 1,500 m/s, the long slide process may reduce the total ∆V

required to 200 to 450 m/s. This is in comparison to the 2,000 m/s typically used for lunar landing 

(Ref. 34). Precise landing control is required and the length of the landing strip area is approximately 

80 km. Additional studies have identified that the dust from the initial phase of the slide landing may 

attain an attitude of 1,300 of km (Ref. 8). Thus, while the landing methods saves much precious 
NASA/TM—2014-218136 7

propellant, the implications of the flying dust on other lunar surface and orbital operations must be 

addressed. 

3.5 Nuclear Pulse Propulsion

Using nuclear devices for propulsion is another product of the creativity of the 1960s engineering and 

physics community (Refs. 35 to 38). The nuclear pulse propulsion (NPP) systems were seriously 

considered for fast transportation throughout the solar system. Small nuclear devices would be detonated 

behind a large piloted spacecraft, and the detonation would power the vehicle. Many 1000’s of such 

pulses were required for outer planet missions. The predicted specific impulse for these vehicles is 

between 1,800 and 6,000 sec (Ref. 34). The NPP vehicles were considered a logical precursor to the 

pulsed fusion propulsion systems, noted in many of the AMOSS studies (where 3He and deuterium 

nuclear fuels are mined from the gas giant planets). 

Nuclear pulse propulsion freighters were conceived to return 3,000 MT payloads of raw or processed 

materials from many targets in the solar system. Figure 10 shows the mission energies, the transportation 

and propellant costs for such a large nuclear freighter (Ref. 8). These analyses noted NPP Isp values from 

6,000 to 10,000 sec (Ref. 8). To support such operations perhaps nuclear bomblet factories would be 

constructed all through the solar system. While constructing large nuclear facilities on every location of 

human exploration may be optimistic, certainly several locations for extended exploration should be 

chosen for such nuclear sites. Smaller nuclear facilities will be a first step, using smaller reactors. 

4.0 Observations

While human missions to Mercury and Saturn and all of the other planets will be challenging and 

require long-term investments, the results from these missions and their development will no doubt have 

great influences on our economy and improve our technological prowess. 

Krafft Ehricke envisioned a poly-global civilization, with branches of humanity in many far flung 

places in our solar system (Ref. 1). His vision was uniquely expressed in Reference 36. Here is a short 

excerpt from that work:

“Our helionauts, as these men who fly our large interplanetary vehicles call themselves in this 

era of continuing specialization, have covered the solar system from the sun scorched shores of 

Mercury to the icy cliffs of the Saturn moon, Titan. They have crossed, and some have died doing 

so, the vast asteroid belt between Mars and Jupiter and have passed through the heads of comets. 

Owing to the pioneer spirit, the courage and the knowledge of our helionauts and of those 

engineers, scientists, and technicians behind them, astrophysicists today work in a solar physics 

station on Mercury; biologists experiment on Mars, backed by a well-supplied research and 

supply station on the Mars moon, Phobos; planetologists have landed on Venus; and teams of 

scientists right now study what have turned out to be the two most fascinating of our solar system, 

Jupiter and Saturn, from research stations on Callisto and Titan. ”

These helionaut flights would be the precursors of human outposts and then colonies all through the 

solar system. Multiple systems employing planetary ISRU could enable all of these ideas and concepts. 

Krafft Ehricke envisioned an entire extensive lunar economy, producing power, finished and raw 

materials, and NPP launching bases for extensive exploration of the solar system. The poly-global 

civilization was considered a natural expansion of the human experience, pioneering new frontiers and 

using technology in the best interests of all humanity. 
NASA/TM—2014-218136 8

5.0 Concluding Remarks

A wide range of space exploration technologies have been assessed in many studies from the 1960s to 

today. In an optimistic future, lunar exploration will lead to base construction and, with time, lead to 

extensive lunar industrial investments. There are a wide range of potential lunar industries: raw materials 

processing, O2 and other propellant production, nuclear and solar power, etc. These industries may lead to 

small scale devices and large scale products: from microchip production to the creation of completely 

new space vehicles. Many of the suggested industries were related to power production to be transmitted 

to Earth or other attractive locales in the Earth-Moon space. 

The need for safe lunar bases may lead to creating underground structures. If extended visits or 

permanent colonization of the Moon is needed, humans will require protection from long term radiation 

exposure as well as intense solar events such as coronal mass ejection, galactic cosmic rays, and lunar 

surface scattering of radiation. Using explosive forming of underground cavities may lead to an attractive 

lunar base or colony. Additional industrialization options include nuclear explosion based processing of 

raw lunar materials. Large scale mining of lunar raw materials and gas production and capture from 

underground nuclear processing of the in-situ materials has been suggested. 

Missions to several planetary targets in the solar system were considered: Mercury, Saturn, and its 

moons, Titan and Enceladus, as well as the asteroid, Ceres. The LEO masses were estimated for the 

Mercury mission scenarios. Lander (ascent/descent) vehicles for Mercury were also assessed. The mass of 

the lander vehicles for Mercury was 140.1 MT for the round trip lander and 27 MT for a one-way deliver 

lander to the surface. Each carried a 10 MT payload. With ISRU, five landers could be delivered to 

Mercury’s surface rather than one. The LEO masses for the human round trip Mercury missions was 

reduced by an order of magnitude, from 27,000 MT to 2,300 or 1,700 MT, using nuclear thermal 

propulsion over chemical O2/H2 propulsion systems. Using ISRU at Mercury would likely further benefit 

a range of such missions. 

Atmospheric mining in the outer solar system can produce nuclear fusion fuels such as 3He which are 

rare on Earth. In addition, while extracting the small fraction of 3He in the gas giant atmospheres, each 

day enormous amounts of H2 and He are produced. These amounts can far outstrip the needed for 

propellants to return the mining aerospacecraft to orbit. These additional H2 and He gases can augment 

many additional UAVs and probes for extended exploration of those planets’ atmospheres and local 

environs. 

Solar system exploration using in-situ resource utilization can allow higher quality missions with 

much large data return. Larger more effective research and sample return missions are possible. Faster 

missions are possible by using the local planetary resources to return to Earth. By not carrying all of the 

return propellants, larger propellant loads in LEO can enable shorter mission flight times. Truly 

impressive interplanetary missions can be within our reach with focused investments. 
NASA/TM—2014-218136 9

Figure 1.—Permanently shadowed craters in Mercury’s North Polar region 

(Ref. 12, used with permission). 

Figure 2.—Temperature ranges outside and inside permanently shadowed craters (Ref. 13). 
NASA/TM—2014-218136 10

Figure 3.—Possible present day cross section of Titan (Ref. 14, reprinted with the permission of 

Cambridge University Press.). 

Human Mercury Mission, Total Mission ∆V = 24.8 km/s

Figure 4.—LEO masses of human round trip missions to Mercury. 
NASA/TM—2014-218136 11

Lander Mass, Chemical Propulsion, Payload = 10 MT,

∆V = 3.5 km/s each, for Descent and Ascent

Figure 5.—LEO masses of lander vehicles for missions to Mercury. 

Figure 6.—One-way interplanetary mission ∆V versus trip time for various targets (Ref. 20).

1

 1

This figure was originally presented at the American Astronautical Society (AAS) 16th Annual Meeting, Anaheim, 

CA, and was originally published in the AAS publication “Space Shuttles and Interplanetary Flight,” ed. L. Larmore 

and R.L. Gervais, Vol. 28, Advances in Astronautical Sciences, 1970, p. 364 (Copyright © 1970 by American 

Astronautical Society Publications Office, Web Site http://www.univelt.com).
NASA/TM—2014-218136 12

AMOSS 3He Mining Time and H2 Capturing Requirements,

3He = 1.9×10-5, Mdry = 1,000,000 kg

Figure 7.—Helium 3 mining time and H2 capture (mass per day) versus atmospheric gas 

capture rate for Neptune AMOSS (Ref. 23). 

Figure 8.—Schematic cross section of a hard rock medium after 

contained nuclear explosion (Ref. 26).

0.01

0.10

1.00

10.00

100.00

1,000.00

10,000.00

100,000.00

1,000,000.00

10,000,000.00

0 10 20 30 40

Time for 3He capturing (days), hydrogen produced 

and required (kg) 

Atmospheric gas capture rate (kg/s)

 

3He 1.9e 5, Mdry 1,000,000 kg 

Time needed for 

capturing 3He (days)

Mass of hydrogen 

produced per day

Gas core, 2500 s

Gas core Mp loads 

per day, 2500 s
NASA/TM—2014-218136 13

Figure 9.—Nuclear detonation processing (Ref. 7). 

Figure 10.—Nuclear pulse propulsion freighter propellant costs for 3.000 MT payload (Ref. 7). 

NASA/TM—2014-218136 15

Appendix A.—Comparison of Several Trajectory Modes for Manned 

and Unmanned Missions to Mercury 1980 to 2000 (AIAA 67-28)

D direct transfer

S unpowered Venus swingby transfer

MPS modified Venus swingby transfer

Figure A.1.—Comparison of Earth orbit weight requirements; manned 

Mercury stopover mission (Figure 10 in Ref. 17). 
NASA/TM—2014-218136 16

TABLE A.1.—MINIMUM ∆V REQUIREMENT; MANNED MERCURY STOPOVER MISSION (TABLE 1 IN REF. 17)

Selected mission design

TABLE A.2.—MINIMUM ∆V TRAJECTORY CHARACTERISTICS—MANNED

MERCURY STOPOVER MISSION (TABLE 2(C) IN REF. 17)

Launch 

year

Earth 

departure date

(Julian)

∆V, 

Earth 

(km/s)

Venus 

swingby date

(J)

∆V, 

Venus 

(km/s)

Mercury 

arrival date 

(J)

Mercury 

arrival ∆V

(km/s)

Stay time

(days)

Mercury 

departure ∆V

(km/s)

Mission 

duration 

(days)

1980 2444336 4.3 2444412 0.9 2444460 6.4 174 6.2 398

1981 4716 8.9 ----------- --- 4801 7.6 183 6.5 383

1982 5000 4.2 5168 --- 5305 8.6 28 7.0 463

1983 5484 4.8 5569 --- 5628 9.4 56 7.4 350

1984 5828 8.1 ----------- --- 5958 6.3 76 7.8 371

1985 6196 7.0 ----------- --- 6306 6.3 180 6.4 365

1986 6562 6.7 ----------- --- 6657 6.3 177 6.2 362

1987 6918 6.9 ----------- --- 7003 6.9 181 6.4 371

1988 7330 5.6 7519 0.9 7630 4.7 18 9.7 383

1989 7680 6.3 7865 --- 7922 8.3 72 8.7 379

1990 8022 8.6 ----------- --- 8157 6.4 77 7.6 367

1991 8356 7.6 ----------- --- 8506 6.3 182 6.8 372

1992 8752 6.8 ----------- --- 8857 6.1 179 6.3 364

1993 9116 6.8 ----------- --- 9206 6.4 178 6.2 368

1991 9650 4.2 9824 --- 9940 7.6 143 7.0 563

1995 9812 6.7 ----------- --- 9897 8.9 186 7.0 401

1996 2450180 4.5 2450305 3.0 2450390 6.8 44 7.4 404

1997 810 4.0 976 --- 1100 7.9 136 6.4 421

1998 946 7.0 ----------- --- 1056 6.5 180 6.4 365

1999 1312 6.6 ----------- --- 1407 6.3 177 6.2 362
NASA/TM—2014-218136 17

References

1. Ehricke, K.A., “Lunar industrialization and settlement - Birth of poly-global civilization,” Lunar 

Bases and Space Activities of the 21st Century Conference, Houston, TX, Lunar and Planetary 

Institute, 1985, p. 827-855. 

2. Ehricke, K.A., “Harenodynamic cooling - The use of lunar sand as cooling medium,” Acta 

Astronautica, Vol. 11, June 1984, p. 319-325. 

3. Ehricke, K.A., “Profitability of manufacturing in space in view of lunar industrial development and 

geo-socio-economic benefits,” Manufacturing in space; Proceedings of the Winter Annual Meeting, 

Boston, MA, Nov. 13-18, 1983, American Society of Mechanical Engineers, 1983, p. 183-198. 

4. Ehricke, K.A., “A socio-economic evaluation of the lunar environment and resources. III -

Selenospheric economics and cislunar/terrestrial market analysis,” IAF Paper 82-235, 33rd

International Astronautical Federation, International Astronautical Congress, Paris, France, Sept. 27-

Oct. 2, 1982, 25 p. 

5. Ehricke, K.A., “A socio-economic evaluation of the lunar environment and resources. II - Energy for 

the selenosphere,” IAF Paper 79-A-16, International Astronautical Federation, International 

Astronautical Congress, 30th, Munich, West Germany, Sept. 17-22, 1979, p. 25. 

6. Ehricke, K.A., A socio-economic evaluation of the lunar environment and resources: I. Principles and 

overall system strategy,” Acta Astronautica, Vol. 8, Issues 11–12, Nov–Dec 1981, pp. 1389-1405. 

7. Ehricke, K., “Lunar industries and their value for the human environment on Earth,” Acta 

Astronautica, 1974. Vol. 1, pp. 585-622. 

8. Ehricke, K., “Further analyses of the slide lander and of drop delivery systems for improved lunar 

surface access,” Acta Astronautica Vol. 10, No. 9, pp. 629 to 650, 1983. 

9. Ehricke, K.A., “Economy of large launch vehicles including orbital labor cost,” AIAA 1963-277. 

10. Ehricke, K., “A comparison of propellants and working fluids for rocket propulsion,” American 

Rocket Society (ARS) Journal, September-October 1953, Vol. 23, No. 5, pp. 287-300. 

MESSENGER at Mercury

11. Lawrence, D.J., et al., “Evidence for Water Ice Near Mercury's North Pole from MESSENGER 

Neutron Spectrometer Measurements.” Science 339, 292 (2013). 

12. Chabot, N.L., Ernst, C.M., Denevi, B.W., Nair, H., Murchie, S.L., Blewett, D.T., Head, J.W.,

Harmon, J.K., and Solomon, S.C., “Imaging Inside Mercury’s Permanently Shadowed Craters - First 

Images From Messenger,” Paper 1693, 44th Lunar and Planetary Science Conference (2013). 

13. MESSENGER Planetary Conference Multimedia Page - David A. Paige, MESSENGER Participating 

Scientist, University of California, Los Angeles, CA. http://messenger. jhuapl. 

edu/news_room/presscon12_multi.html with: David A. Paige, et al., “Thermal Stability of Volatiles 

in the North Polar Region of Mercury,” Science, January 18, 2013: Vol. 339, No. 6117, pp. 300-303. 

Cassini at Saturn

14. Tobie, J.I., Lunine, J., Monteux, O., Mousis and Nimmo, F., “The Origin and Evolution of Titan,” in 

Titan: Interior, Surface, Atmosphere and Space Environment, Muller-Wodarg, Griffith, Lellouch and 

Cravens, eds., Cambridge Univ Press, pp. 24-50, 2012. 

http://www.es.ucsc.edu/~fnimmo/website/Tobie_Titan.pdf. 

15. Spencer, J.R. and Nimmo, F., “Enceladus: An active ice world in the Saturn System,” Annual Review 

of Earth and Planetary Sciences 41, 693-717, 2013. 

Ceres

16. Rambaux, N., Castillo-Rogez, Dehant, J.V. and Kuchynka, P., “Constraining Ceres’ interior from its 

Rotational Motion,” Astronomy & Astrophysics, manuscript no. Ceres ̇Rambauxetal 11 ESO 2011,

July 12, 2011, arXiv:1107.2051v1 [astro-ph.SR] 11 Jul 2011. 
NASA/TM—2014-218136 18

Mercury mission design

17. Manning, L. “Comparison of Several Trajectory Modes for Manned and Unmanned Missions to 

Mercury 1980-2000,” AIAA 67-28, 1967. 

18. Marx, G., “Model study of fuel requirements for fast interplanetary flights using advanced nuclear 

propulsion systems and refueling at destination,” Thesis, Technical University of Berlin (West 

Germany), In German, May 9, 1967. 

19. Ehricke, K., “Study of Interplanetary Missions to Mercury Through Saturn With Emphasis on 

Manned Missions to Venus and Mars 1973/82 Involving Capture,” Engineering Problems of Manned 

Interplanetary Exploration, 1963, AIAA 1963-1514. 

20. Ehricke, K., “Perspective and Systems Engineering of Manned Planetary Flight,” AAS 70-037, 1970. 

In: Space Shuttles and Interplanetary Flight, Vol. 28, Advances in Astronautical Sciences, 1970. 

21. Palaszewski, B., “Metallized Propellants for the Human Exploration of Mars,” NASA Lewis 

Research Center, NASA TP-3062, presented at the Case For Mars IV Conference, Boulder, CO, June 

4-8 1990. Also in the AIAA Journal of Propulsion and Power, Vol. 8, No. 6, Nov.-Dec. 1992, pp. 

1192-1199

22. Bensky, M., “Propulsion requirements for soft landing in extraterrestrial environments,” Rocketdyne, 

NAS7-124, NASA CR-55088, Feb. 1963. 

Atmospheric mining in the outer solar system (AMOSS)

23. Palaszewski, B., “Atmospheric Mining in the Outer Solar System: Resource Capturing, Storage, and 

Utilization,” AIAA 2012-3742, July 2012. 

24. Palaszewski, B., “Atmospheric Mining in the Outer Solar System: Issues and Challenges for Mining 

Vehicle Propulsion,” AIAA 2011-6041, August 2011. 

Nuclear processing: 

25. Looper, M., “Radiation environment near the lunar surface CRaTER observations and Geant4 

simulations,” Space Weather, Vol. 11, pp. 142-152, 2013. 

26. Cohen, G.D.; Sand, F.M., “Water Resource Applications, Underground Storage of Natural Gas, and 

Waste Disposal Using Underground Nuclear Explosions,” Mathematica, Inc., Princeton, NJ, 31 Aug 

1967: http://www.dtic.mil/get-tr-doc/pdf?AD=ADA395557 .

27. Morrey, Jr , C.B.; Pinney, E.; Stoneham, R.G.; Chambre, P.L.; Lakness, R.M. “Underground 

Explosion Theory,” University of Berkeley, CA, Apr 1952: http://www.dtic.mil/get-trdoc/pdf?AD=AD0608885 .

28. Sachs, D.C.; Swift, L.M., “Underground Explosion Effects,” Stanford Research Inst., Menlo Park, 

CA, 03 Mar 1958: http://www.dtic.mil/get-tr-doc/pdf?AD=AD0617181 .

29. Brode, H.L., “Nuclear Explosions in Cavities,” Rand Corp., Santa Monica, CA, Nov 1965.

30. Brode, H.L., “More Nuclear Explosions in Cavities,” Rand Corp., Santa Monica, CA, Jun 1968.

31. Hoffman, G.A., “Thermoelectric Powerplants Utilizing Contained Nuclear Explosions,” Rand Corp., 

Santa Monica, CA, 18 Feb 1960.

32. Gruber, S., “Charged Particle Beam-Plasma Interactions for Thermonuclear Power Generation,” Final 

report, Case Western Reserve Univ., Cleveland, OH, Dept. of Electrical Engineering and Applied 

Physics, Jun 1974. 

33. Wong, H.V.; Kotschenreuther, M.T.; Breizman, B.N.; Van Dam, J.W.; Hazeltine, Richard D.,

“Assessment of Compact Low Neutron Fusion Reactor Concepts,” Final report, 15 Jun 1999-30 Nov 

2000, Texas Univ. at Austin Inst. For Fusion Studies, 16 Feb 2000: http://www.dtic.mil/get-trdoc/pdf?AD=ADA387427.

34. Palaszewski, B., “Lunar Missions Using Advanced Chemical Propulsion: System Design Issues,” 

NASA Lewis Research Center, NASA TP-3065, AIAA 90-2341, presented at the 26th 

AIAA/ASME/SAE Joint Propulsion Conference, Orlando, FL, July, 1990, also in AIAA Journal of

Spacecraft and Rockets, Vol. 31, No. 3, May-June 1994, pp. 458-465. 
NASA/TM—2014-218136 19

Nuclear pulse propulsion

35. Ehricke, K.A., “Interplanetary maneuvers in manned helionautical missions,” 1965, AIAA 1965-695. 

36. Ehricke, K.A., “Solar Transportation,” Presented to the 4th Goddard Memorial Symposium, AM. 

Astronautical Soc., Washington, D.C., 15-16 Mar. 1966. 

37. “A Grand Vision of Man’s Role in Colonizing the Universe” by Oyang Teng, LaRouche Youth 

Movement (book review), Marsha Freeman, “Krafft Ehricke’s Moon: The Extraterrestrial 

Imperative,” Technology Editor of Executive Intelligence Review, 2009. 

http://www.21stcenturysciencetech.com/Articles_2009/Summer-2009/Extraterrestrial_Imperative.pdf

38. Schmidt, G.R., Bonometti, J.A., and Irvine, C.A., “Project Orion and Future Prospects for Nuclear 

Pulse Propulsion,” Journal of Propulsion and Power, Vol. 18, No. 3, May–June 2002. 
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Solar System Exploration Augmented by Lunar and Outer Planet Resource Utilization:

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13–17, 2014.

14. ABSTRACT

Establishing a lunar presence and creating an industrial capability on the Moon may lead to important new discoveries for all of human kind. Historical studies of lunar

exploration, in-situ resource utilization (ISRU) and industrialization all point to the vast resources on the Moon and its links to future human and robotic exploration. In the

historical work, a broad range of technological innovations are described and analyzed. These studies depict program planning for future human missions throughout the solar

system, lunar launched nuclear rockets, and future human settlements on the Moon, respectively. Updated analyses based on the visions presented are presented. While

advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal propulsion, nuclear surface

power, as well as advanced chemical propulsion can significantly enhance these scenarios. Robotic and human outer planet exploration options are described in many detailed

and extensive studies. Nuclear propulsion options for fast trips to the outer planets are discussed. To refuel such vehicles, atmospheric mining in the outer solar system has also

been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as helium 3 (3He) and hydrogen (H2

) can be wrested from the

atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and H2

 (deuterium, etc.) were the primary gases of interest

with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses have investigated resource

capturing aspects of atmospheric mining in the outer solar system. These analyses included the gas capturing rate, storage options, and different methods of direct use of the

captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of

additional exploration and exploitation vehicles exists.

15. SUBJECT TERMS

Propulsion; Rocket; Nuclear power; Propellants; In situ resource utilization (ISRU); Orbit mechanics

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