Prepared by:
Paul D. Campbell, Principal Engineer
Man-Systems Department
Approved by:
J. D. Harris, Operations Manager
Man-Systems Department
For:
Man-Systems Division
National Aeronautics and Space Administration
Lyndon B. Johnson Space Center
Houston, Texas
January 1992
The document contains preliminary information on the Space Exploration Initiative terrestrial analog program gathered from a variety of sources. It does not represent the official definition of any part of that program, but instead is a technical report on selected potential analog environments, missions, and systems.
Further information on the study may be requested from Jeri Brown, Division Manager for Lunar/Mars Exploration, NASA/JSC Man-Systems Division, (713) 483-6036.
In planning the SEI, the concept of terrestrial missions which in some ways simulate Lunar and Mars missions has been proposed as one method to increase knowledge about long-term human and machine operations in harsh environments. These analog missions and their associated facilities and systems can be viewed as a risk management technique for the SEI program by yielding early information to support the planning of SEI missions and the development of the associated space systems.
The NASA Headquarters Office of Exploration and the Lunar and Mars Exploration Program Office (LMEPO) at the NASA Johnson Space Center (JSC) are utilizing the Synthesis Group report as a guide in the planning of SEI programs and missions. Orbital Node, Space Transportation, and Planet Surface integration agents within NASA are performing systems engineering and integration analyses which support SEI mission studies.
As the candidate space flight missions become more clearly defined over the next one to two years, they can also provide the context for the planning of terrestrial analog missions.
The H&HS team's efforts are applicable to the development of terrestrial analogs which simulate Lunar and Mars habitats. In light of this fact, a study of terrestrial analogs was performed to apply H&HS knowledge and skills to the problem of defining potential analog habitation systems.
The intent of the study is to systematically examine a range of issues associated with terrestrial analog habitation and to separate those issues to the point that useful conclusions can be drawn. This was accomplished by starting with a broad range of potential analog missions and environments, then focusing on one specific mission-environment combination as the context for habitation operations and systems analysis.
Section 2.0 of this document describes the SEI analog program as it currently exists and details potential analog mission objectives and terrestrial environments.
Section 3.0 is specific to the human and habitation aspects of terrestrial analogs, and describes potential requirements, concepts, test opportunities, and benefits related to a specific analog mission and environment.
Earliest SEI analogs could be implemented at low cost in existing terrestrial facilities such as NASA human-rated test facilities, sub-sea laboratories, or polar camps. New terrestrial facilities, specifically designed for SEI, would then be appropriate to increase the analog mission fidelity. Low Earth orbit facilities, such as the Space Station Freedom, would provide even more realism along some space flight parameters such as reduced gravity and radiation exposure. A Lunar outpost is seen as the ultimate analog to a Mars mission, but is expected to cost much more than any of the other methods described here.
Figure 2.0-1 illustrates the concept of a phased set of analog missions which build from early, low fidelity analogs to later, high fidelity analogs. This study focuses on the phase labeled "New Terrestrial Analogs", which should begin development in the near term in order to provide benefits for initial Lunar human missions.
In every analog, an appropriate mix of systems testing, human research, and mission operations simulation is necessary to achieve early SEI milestones, both technical and strategic.
The Synthesis Group report (reference 2) recommends the use of Lunar missions over terrestrial analogs to simulate a Mars mission. Separately, it describes needs for Earth-based preflight crew training in high fidelity simulators, geology training at appropriate locations on Earth, new ground facilities including a life support test facility, and life sciences research into human factors including psychosocial issues and habitat design, but it does not recommend the use of terrestrial analogs to fulfill any of these needs.
The SEI analog program currently being defined includes cooperation between the NASA and the National Science Foundation (NSF), the U.S. agency responsible for managing polar programs. A memorandum of agreement between the two agencies defines the scope of the cooperative effort (reference 3).
The NASA portion of the SEI analog program is managed by NASA headquarters, with program science management by the Office of Space Science and Applications (OSSA). Project management is performed by the LMEPO. Technical studies are being performed by the Planet Surface Systems Office (PSS) at JSC.
The NSF Division of Polar Programs administers the U.S. Antarctic Program (USAP), and as such is the lead NSF organization implementing the agreement with NASA.
"Scientific needs and opportunities should determine the research conducted in both polar regions, with logistics deriving from and supporting the research rather than dictating it.The NSF has a need for new approaches to the design of human stations which can provide enhanced capabilities for the human crews and which can reduce environmental impacts created by the stations' presence. Reference 3 states:"The health, safety, and environmental protection practices for polar research program, especially the U. S. Antarctic Program, should be studied and upgraded as necessary.
"Basic engineering research should be conducted in the polar regions, with development of the engineering knowledge required for operation in the polar environment a specially targeted objective."
"NSF interests under this agreement are to: identify advanced technologies that offer potential short and long-term benefits to planned antarctic base improvements/initiatives, apply and test promising technologies..., optimize living/working conditions at antarctic and other polar facilities, reduce operations logistics costs through improved ... waste management systems, reduce environmental impacts of antarctic bases, advance antarctic research ... in areas of mutual interest such as ... human behavior and performance ...."NSF goals are enunciated in a joint report with NASA (reference 5):
"NASA interests under this agreement are to: provide for scientific research..., realize early demonstrations of crew operations under realistic environmental and working/living conditions, demonstrate vital planetary surface and terrestrial technologies, including ... waste control/recycling ..., demonstrate environmental and other benefits of space technology, ...."NASA goals are enunciated in reference 5:
"Future human exploration activities will be supported by augmented ground- based research efforts in advanced medical care, ... closed-loop life support, and human factors. This research, much of which will involve studies within suitable analog environments, will establish a firm foundation for the planning of future human missions."
NSF plans include the development of a permanent scientific facility on the Antarctic polar plateau. This facility would support up to twenty personnel for scientific work in astronomy, space physics, geology, and aeronomy (reference 7).
NASA's plans for analog development are partially delineated in the SEI Long-Range Plan of January 1991 (reference 8). This document defines the initiation of Antarctic studies for human support in 1992. It also defines an analog program with phase A in 1993, phase B in 1994, and phase C/D in 1995-1996. A Lunar habitat testbed for life support is defined in 1994, with a human-rated regenerative life support capability in 1996.
The PSS has defined an Antarctic analog schedule as shown in Figure 2.2-1 (reference 9). This program includes analog hardware delivery to Antarctica in 1997 and completion of analog construction in 1998, with operations beginning in 1998. The PSS has also defined operations and logistics studies in 1991, a system evaluation in 1993, and continuing terrestrial analog efforts through 2005 (reference 10).
Scheduling of analog projects is expected to be influenced by the overall SEI program schedule, by available resources, and by progress in technology development. Mission definition should be carried out in the near term in order to fully study analog mission objectives and issues prior to commitment of resources for analog systems development.
Human research, as used in this study, encompasses all areas of health, safety, and productivity applicable to SEI crews on missions to the moon and to Mars. Some of these areas cannot be fully investigated through a terrestrial analog, but many can benefit from such a test bed.
Physical sciences research includes the types of science currently being performed in extreme terrestrial environments, as well as additional research directly applicable to SEI missions.
Flight systems development consists of the end-to-end effort required to define, develop, fabricate, and test the hardware and software which will support human crews on SEI space missions. This includes all the necessary ground-based technology development, advanced development, and flight systems engineering.
Sections 2.3.1 describes mission concepts tailored to these three potential mission objectives.
Potential environments for terrestrial analog operations include the Earth's atmosphere, seas, and land. Each of the environments offers some degree of simulation for SEI space missions. Some have more advantages than others for particular mission objectives.
Terrestrial environments of potential use for an SEI analog program are discussed in section 2.3.2. Each is described in terms of characteristics which may correlate to SEI space mission environments.
The following subsections provide additional details on potential mission objectives for SEI terrestrial analogs. It is expected that elements of each of these potential objectives will be utilized in formulating actual analog missions. They are separated here for purposes of illustration and to demonstrate the potential operational variations when one mission objective is emphasized over the others. Figure 2.3.1-1 illustrates the concept of an integrated set of mission objectives which results in more analog benefits than would isolated missions designed around each individual objective.
A terrestrial analog which simulates some of the conditions expected in SEI missions can provide researchers with information on changes to be anticipated in human crewmembers during missions to the moon and Mars. Emphasis would be on conditions which affect human health, behavior, and performance. An analog environment for this mission might involve extremes of temperature, pressure, gravity, daylight/darkness, or other physical factors, resulting in crewmember perceptions of isolation, confinement, deprivation, and risk; changes in physical or cognitive task performance; and/or changes in the performance of human body systems.
To produce valid human research data, the analog mission crewmembers must be involved in work which is professionally relevant to them and they must perceive the rewards of the mission to be commensurate with the personal costs to them (reference 11).
Human research parameters of interest in this mission (references 12, 13, 14) include:
The analog mission length and crew size are based on biobehavioral research considerations to simulate an initial Mars mission of up to three years. The analog environment is also selected based principally on biobehavioral considerations, with high levels of environmental hostility, isolation, confinement, and perceived risk as some of the selection criteria. The analog facility's fidelity to flight systems is not high, but analog systems are designed to enhance crew health, safety, and productivity. The habitat interior is of high enough quality that it simulates essential characteristics of a space mission habitat. It includes all functions necessary to support humans for durations up to three years, with resupply of consumables during that period.
The analog crewmembers receive a degree of training prior to their mission similar to that of space flight crews. They are provided with satellite, aerial, and surface photography of the analog site and region, but they have no trip to the site prior to their mission.
The crew consists of a mix of military pilots with engineering degrees, medical doctors, psychologists, and physical scientists. Married couples are utilized when possible.
Crew operations emphasize testing and measurement of physiological and psychological performance variables. Mission operations are mainly internal to the habitable elements, but external operations are used to generate human performance data and to operate and maintain the analog facility. Remote communications with mission control personnel, flight surgeons, and family members are frequent and include two-way voice, text, graphics, and video. Time delays are added to communications to simulate the signal lag times on a mission to Mars.
A concept for the physical sciences mission is summarized in the following paragraphs.
The analog mission length and crew size are based on physical science considerations. The analog environment is also selected based on physical science considerations, with a high level of science opportunity and a high degree of similarity to planet surfaces as important selection criteria. The analog facility fidelity to flight systems is not high, and analog systems are designed to ensure acceptable levels of crew health, safety, and productivity. The analog includes all functions necessary to support a crew for durations up to one year, with resupply of consumables during that period. The analog includes a dedicated physical sciences laboratory for analysis and curation of geological samples.
The analog crew consists of engineers, medical doctors, and physical scientists.
Crew operations emphasize surface exploration and sampling, experiment package deployment and monitoring, and laboratory analysis. Remote communications with mission control personnel, flight surgeons, and family members are only as frequent as necessary to ensure crew safety and to exchange scientific information with investigators at mission control.
A concept for the systems development mission is summarized in the following paragraphs.
The analog mission length and crew size are based on systems testing considerations. The analog environment is selected based on systems life testing considerations, with high levels of environmental hostility and logistics difficulty as important selection criteria. The analog facility fidelity to flight systems is high in order to test the technologies and the designs of prototype SEI space systems for their functionality, reliability, and maintainability. The habitat includes all functions necessary to support humans for durations up to three years, with resupply of consumables during that period. The habitat also has the capability for human-tended operations in which critical habitat functions are maintained between human visits.
The analog crewmembers receive flight-like training prior to their Antarctic mission, especially in the maintenance of the analog systems. The crew consists of a mix of engineers and medical doctors.
Crew operations emphasize testing and maintenance of analog systems. External operations on the surface terrain are frequent in order to operate and maintain the analog facility. Remote communications with mission control are only as frequent as necessary to exchange information on systems performance and crew health. Time delays are added to communications to simulate the signal lag times on a mission to Mars.
It is assumed that NASA will produce an analog facility tailored to its own purposes which could be designed for any of the following environments. It is also assumed that NASA will make maximum use of existing transportation and remote communications infrastructure where possible.
It is accepted that all terrestrial environments differ from SEI mission environments in significant ways, such as gravity and ionizing radiation levels. Each potential analog environment is described in terms of the following characteristics which may vary from one to another and which may affect its appropriateness as a site for an SEI analog facility:
Hostility: high, due to storms, with polar seas very high due to temperatures
Confinement: moderate in temperate seas if diving available; high in polar seas
Risk: high to very high, based on storms and remoteness from medical care
Prior knowledge: high for general characteristics, moderate for prevailing winds and ocean currents, low for specific events such as storms
Natural lighting: ranges from equatorial day/night cycle to North Polar continuous summer light and continuous winter darkness, depending on the sea surface location
Logistics difficulty: low to high depending on sea surface location and whether the analog is fixed or mobile; logistics via aircraft is constrained by the distance to the nearest airport and the need for a water landing or onboard landing pad, and logistics by ship may be constrained by distance to the nearest port
Remote communications: potentially real-time communications via satellite links, but lack of such capability may cause less overall communications capability than that anticipated for SEI missions (less reliable, less frequent communications); mobile analogs such as ships may have periods of very low communications capabilities when not in range of a continuous satellite link
Science opportunity: high for studying the ocean and atmosphere, but would not be similar to Lunar or Mars science in most ways
Similarity to planet surface: very low except in cases of sea pack ice such as at the North Pole which could allow crew surface traverses
Sensitivity: relatively low for overboard dumping of gaseous and liquid wastes, moderate for dumping of solid wastes
Hostility: very high, as crew cannot survive outside for more than a few minutes without breathing devices and/or thermal suits
Confinement: ranges from low to high, depending on location and depth, with deep, cold environments producing highest confinement
Risk: moderate risk in habitat, high risk outside due to communication, visibility, currents, temperatures, sea life, and ocean floor features; bends risk must be managed when decompressing
Prior knowledge: high for general conditions, but low for details such as sea bottom features which are site-specific and may change over time
Natural lighting: at shallow depths the local day/night cycle will be apparent, but at deep locations no natural lighting will exist
Logistics difficulty: moderate to high, depending on location and depth, with remote, deep sites producing high logistics difficulty, especially for resupply of consumables which must remain dry
Remote communications: potentially real-time communications via satellite links, but lack of such capability may cause less overall communications capability than that anticipated for SEI missions (less reliable, less frequent communications)
Science opportunity: high for biological and physical science as well as human research, but ocean-specific science is not highly analogous to Lunar/Mars missions
Similarity to planet surface: low for sea-bottom characteristics, but partial gravity simulation by weighted buoyancy may be possible
Sensitivity: moderate to high, based on potential impacts to bottom life such as coral reefs
The following subsections describe generic land surface environments which may be of use in locating analog facilities and conducting analog missions.
Hostility: low, based on sites of current NASA installations
Confinement: low if based only on the environment as a driver, must be enforced by crew procedures if it is desirable to study high degrees of confinement
Risk: low due to climate and proximity of extensive medical facilities
Prior knowledge: very high, unless surface features are intentionally changed to reduce the crew's prior knowledge of them
Natural lighting: mid-latitude day/night cycle
Logistics difficulty: low due to proximity to sources of analog elements and resupply consumables and high level of existing transportation infrastructure
Remote communications: reliable and frequent communication to mission control via existing NASA telecommunications network
Science opportunity: low for surface science, and low for human research other than long-term self-imposed confinement
Similarity to planet surface: low at existing sites, but surface simulator could be prepared as part of the analog ("rock pile")
Sensitivity: low, based on much larger amounts of human activity already occurring at the site
Hostility: low to moderate depending on location and season, based on temperatures and storms
Confinement: low to moderate depending on location and season
Risk: low to moderate based on lack of significant environmental hazards
Prior knowledge: high for general characteristics; low to high for site-specific features, depending on whether crewmembers have detailed information before the mission
Natural lighting: mid-latitude day/night cycle
Logistics difficulty: low to moderate, depending on existing land transportation infrastructure
Remote communications: possibly more reliable and frequent than that of SEI missions based on existing geostationary satellite links
Science opportunity: moderate to very high for surface geology, moderate for human research in isolation and confinement
Similarity to planet surface: moderate to high for Mars, low to moderate for moon
Sensitivity: moderate, based on potential impacts to desert geology and biology
Hostility: low to high, depending on latitude and season
Confinement: low based on environment, except high in polar regions
Risk: low to moderate, depending on the extent of off-shore diving performed and proximity to inhabited areas with medical facilities
Prior knowledge: low to high, depending on whether crewmembers have been to the site and/or been given photographic information before the mission
Natural lighting: equatorial to polar conditions
Logistics difficulty: moderate to high, depending on proximity of airfields and ports and terrain of island
Remote communications: low to high reliability and frequency, depending on latitude and longitude
Science opportunity: high for biology and ocean studies, but may be low for geology and human confinement studies
Similarity to planet surface: low to high, depending on island, with recently volcanic islands providing higher similarity to Mars surface
Sensitivity: high to very high, depending on the ecology of the selected island
Hostility: moderate to high, depending on elevation, with factors being hypoxic atmosphere, extreme low temperatures, high winds, and snow
Confinement: moderate to high, with low temperatures and hypoxic conditions resulting in a high degree of confinement, depending on the outdoor clothing and portable oxygen supplies provided
Risk: moderate to high, based on possibility of weather which could prevent crew emergency evacuation as well as potential exposure to ambient conditions
Prior knowledge: high to low, depending on whether crewmembers have been to the site and/or been given photographic information before the mission
Natural lighting: near-equatorial to near-polar lighting conditions, depending on analog site, cloudy to clear conditions depending on location and elevation
Logistics difficulty: high to very high, depending on location, elevation, slope, and terrain
Remote communications: low to high reliability and frequency, with higher reliability and frequency based on use of geostationary satellite links
Science opportunity: moderate to high for geology, high for human research, moderate to high for astronomy or microbiology
Similarity to planet surface: low to high, depending on surface cover of ice and snow versus rocky surface and depending on site slopes versus planet surface site slopes
Sensitivity: moderate to high, depending on the ecology of the selected site
Hostility: moderate to very high, depending on temperature, weather, and surface cover
Confinement: moderate to very high, depending on weather and season
Risk: moderate to high, based on possibility that crew medical evacuation could be delayed depending on site and weather
Prior knowledge: high to low, depending on whether crewmembers have been to the site and/or been given photographic information before the mission
Natural lighting: several months of continuous light in summer, several months of continuous darkness in winter, and day/night cycles during spring and fall
Logistics difficulty: moderate to high, depending on location and surface cover and degree of use of existing infrastructure
Remote communications: low to moderate, depending on the availability of periodic links through high orbit inclination satellites and/or the ability to transmit line-of-sight to geostationary satellites
Science opportunity: moderate for geology, moderate to high for oceanography and ocean biology, low for astronomy
Similarity to planet surface: low to moderate, depending on site surface cover of ice or bare ground; land sites are not available near the North Pole, the farthest north land site being TBD degrees latitude
Sensitivity: high, based on fragile ecology and long recovery times
Hostility: moderate to high, based on low temperatures and high winds
Confinement: moderate to high, depending on seasonal temperatures and winds
Risk: moderate to high, based on availability of emergency evacuation to McMurdo in summer but not in winter
Prior knowledge: moderate to high, depending on whether crewmembers have been to the site and/or been given photographic information before the mission
Natural lighting: continuous light in austral summer, continuous darkness in austral winter, with light/dark cycles in spring and fall
Logistics difficulty: moderate, based on helicopter-only access from McMurdo
Remote communications: moderate reliability and availability, based on use of terrestrial radio links and/or links through high orbit inclination satellites
Science opportunity: high for geology, high for microbiology in lakes, moderate for human research, low to moderate for astronomy, based on winds and dust
Similarity to planet surface: high for Mars surface, moderate for Lunar surface
Sensitivity: high, based on fragile ecology and long recovery times
Hostility: high, based on low temperatures and hypoxic atmosphere
Confinement: high to very high, based on hostility and lighting conditions, depending on season
Risk: high, based on time required to perform emergency medical evacuation and on potential for crew exposure to ambient conditions
Prior knowledge: high on general characteristics, low on specific features and weather events
Natural lighting: continuous light in austral summer, continuous darkness in austral winter, with light/dark cycles in spring and fall
Logistics difficulty: moderate to high, based on use of sea transport to McMurdo and air transport from McMurdo to the polar plateau during summer but not during winter
Remote communications: moderate reliability and availability, based on use of terrestrial radio links and/or links through high orbit inclination satellites
Science opportunity: high for human research, low for geology, high for astronomy, high for atmospheric research
Similarity to planet surface: low, based on ice and snow cover
Sensitivity: high to very high, due to low wind velocities and low precipitation amounts
Hostility: low to moderate, based on lack of weather effects and low but constant temperature
Confinement: high to very high, dependent on implementation in a large cavern or in a small excavation
Risk: low, assuming medical evacuation is readily available
Prior knowledge: high to low, depending on whether crewmembers have been to the site and/or been given information before the mission, natural caverns will have more unknowns than man-made excavations
Natural lighting: none, except for artificial lighting
Logistics difficulty: low to moderate, based on short distance from surface
Remote communications: high reliability and continuous link availability
Science opportunity: moderate to high for subsurface geology, high for human research, none for astronomy or surface exploration
Similarity to planet surface: low to moderate, if lava tubes are considered
Sensitivity: low if man-made excavation, potentially high if natural cavern due to very long recovery time
Hostility: moderate to very high, based on weather effects and altitude effects
Confinement: high to very high, depending on altitude
Risk: moderate to high, depending on location and fixed or mobile operations
Prior knowledge: high for general characteristics, but low for specific events such as atmospheric storms which are not predictable further than a few days in advance
Natural lighting: cyclic based on local day/night period
Logistics difficulty: moderate to very high, depending on fixed or mobile operations
Remote communications: moderate to high availability, depending on location
Science opportunity: high for atmospheric science, moderate to high for astronomy, very low for surface geology
Similarity to planet surface: very low
Sensitivity: low
Model: Habitation systems provide compatibility between humans, missions, and environments.
Figure 3.1-1 Human-Mission-Environment-Habitation Systems Model
Following is a list of assumptions made to provide the context for this analog concept:
Remote communications may be limited by the periodic availability of satellite links.
Surface operations, including crew traverses and science activities are possible, though the surface terrain does not resemble Lunar or Mars terrain.
The winter-over period extends for at least eight months and includes several months of continuous darkness.
The high altitude of the site drives a need for control of the habitat atmosphere to prevent crew hypoxia.
Transportation to and from the site is assumed to be by aircraft, similar to that at the South Pole Station.
No assumption is made as to the availability of unpressurized surface rovers for local transportation, but it is assumed that a pressurized rover is not part of the analog.
Suits are worn by crewmembers outside the habitat which protect them against the environment, allow voice communication with the habitat and with each other, and provide a respirable atmosphere with approximately sea-level equivalent oxygen pressure.
The analog facility power generation capability is independent of season and time of day and presents no exceptional problems for crew maintenance.
Crews of up to six individuals shall be accommodated for periods up to three years.
Operations shall be performed to simulate Lunar and Mars mission activities and crew performance.
Human research to be performed shall include measurements of physiological, biobehavioral, and productivity parameters and factors affecting them.
Physical science research shall include atmospheric and meteorological observations, astronomy, and collection of surface and subsurface samples.
Systems development and testing shall include habitat emplacement and construction, logistics and maintenance, power generation, communications, life support, health care, and crew accommodations equipment.
Transportation to and from the analog site for hardware, consumables, and personnel shall be provided by existing Antarctic aircraft capabilities.
Medical evacuation of analog crewmembers to McMurdo Station shall be provided within TBD hours of communication of the need.
Evacuation of all personnel at the analog site to the South Pole Station shall be provided within TBD hours of communication of the need.
Remote communication between the analog site and the South Pole Station, other Antarctic stations, and the continental United States shall be provided.
Environmental impacts of the analog mission shall be minimized by containing mission byproducts and wastes and periodically removing them from the analog site.
Table 3.2.1.2-1 defines the ranges of environmental conditions to be imposed as design requirements on the analog systems (reference 16). The low wind speed lengthens to several days the time required for the dispersion of aircraft exhaust products, the high altitude presents hypoxia concerns for personnel, and the dry air increases human body moisture loss (reference 7).
Preliminary environment-related requirements on the habitation systems are:
Analog systems shall be designed to be restarted after reaching equilibrium with the polar plateau environmental conditions.
Analog systems shall minimize impacts to the mission environments.
Analog systems should withstand as wide a range of environmental conditions as possible without undue impacts on cost, schedule, or functional performance.
| Parameter | Yearly Range of Values | |
|---|---|---|
| Position (latitude, longitude) | 82 degrees south, 85 degrees east | |
| Range from McMurdo | approximately 1800 km (1100 miles) | |
| Altitude | 3993 meters (13,100 feet) | |
| Atmospheric pressure | As low as 55 kPa (8 psia) | |
| Wind speed | Average | 3.0 m/sec (6.7 mi/hr) |
| Maximum for design | TBD | |
| Air-borne particulates | TBD | |
| Precipitation | 1-5 cm/yr (0.39-1.96 in/yr) | |
| Radiation | Solar | TBD |
| Cosmic | TBD | |
| Sunlight | Summer | Continuous light for 130 days |
| Winter | Continuous darkness for 120 days | |
| Spring/Fall | Transition over approximately 60 days | |
| Air temperature | Maximum | TBD |
| Minimum | -90 degrees C (-130 degrees F) | |
| Average | TBD | |
| Relative humidity | TBD | |
| Ground temperature | Surface | TBD |
| 10 cm subsurface | TBD | |
| 1 m subsurface | TBD | |
| Surface characteristics | Density | TBD |
| Penetration resistance | TBD | |
| Ice sheet motion | TBD m/yr, TBD direction | |
| Seismic Events | Magnitude | TBD |
| Frequency | TBD | |
The following subsections define potential requirements, concepts, technologies, test opportunities, and terrestrial benefits related to each of the habitat subsystems.
Currently, most United States surface cargo transported to Antarctica by ship is offloaded at McMurdo Station (77 degrees south, 166 degrees east). Air transport to the continent is by cargo aircraft to the McMurdo vicinity. Wheeled aircraft are landed on the Ross Sea ice in the austral spring (October-November), until the sea ice runway becomes unusable. Ski-equipped aircraft are then landed at Williams Field on the Ross ice shelf during December-February (references 17 and 18). Most flight operations are suspended for the winter-over period from late February until October.
The existing transportation infrastructure inside Antarctica provides a capability for the movement of modular systems and equipment. The LC-130 transport is used as the primary aircraft for movement of personnel, equipment, and supplies to the interior of the Antarctic continent, including the South Pole Station and remote field camps. Flights between McMurdo and South Pole Station occur from late October through early February (reference 18).
The United States C-141 and C-5 aircraft are also flown to Antarctica, but may not be landable at the selected polar plateau site due to their requirements for permanently bare "blue ice" conditions (reference 19). The advantages of either of these aircraft are their larger payload mass and volume capacities, which could allow larger preintegrated habitat elements to be emplaced.
Reference 20 describes the cargo loading and transport characteristics of all three of these candidate heavy lift aircraft. Air drop of cargo from either of these aircraft is a potential method of delivery of large cargo to sites without hard surface runways.
UH-1N helicopters are used inside Antarctica to transport personnel and small equipment. Their primary uses are the movement of summer science researchers to small remote campsites near McMurdo and the evacuation of personnel to McMurdo in emergencies. The altitude and range limitations of the UH-1N rule it out for support of a polar plateau analog.
Loading and unloading of transport aircraft cargo at the analog site may require a propulsive capability, either in the cargo itself, or in a surface vehicle. If the C-141 or C-5 were landed at a "blue ice" location, overland transport of analog elements by tractor-sledge train could be used to move them to the analog site.
Table 3.2.2.1-1 describes some of the characteristics of the LC-130, C-141, and C-5 aircraft and their payload capabilities. It is expected that the LC-130 will be the favored means of transport of analog habitat hardware for both hardware and personnel. Its current operational capability to the South Pole Station would also allow service to the polar plateau site from McMurdo, a distance of approximately 1800 km (1100 miles).
Historically, the U. S. Plateau Station elements were transported in a period of three weeks in 1965 using LC-130 transports. This involved moving four prefabricated living units, each weighing 10400 kg (23,000 lbs), two heavy tracked vehicles, fuel storage bladders, and 189,000 liters (50,000 gal) of diesel fuel (reference 21). The Plateau Station was at 3624 m (11,890 ft) altitude, 79 degrees south latitude, 40 degrees east longitude. The Plateau Station location and transportation mode are similar to those of the analog mission concept defined in this study.
As a more recent example of an extensive transport project, USAP task S-272, Long Duration Ballooning Test Flight in Antarctica, was scheduled for 1990-1991 and required the transport of 66,000 kg (145,000 lb) of cargo to and from the Antarctic continent. Both ship and air transport to McMurdo were planned for this project (reference 22).
Preliminary transport-related requirements on the analog habitation systems are:
Self-propelled elements shall be capable of unloading from the aircraft under their own power. Non-self propelled elements shall be capable of removal from or placement in the LC-130 with the use of surface support vehicles.
Figure 3.2.2.1-4 illustrates a conceptual method of transport for preintegrated habitable elements to the Antarctic polar plateau site by LC-130 or larger aircraft. Habitat technology candidates for this concept are available within the current state of engineering practice. Reference 23 describes the U. S. Air Force's Airborne Battlefield Command Control Center, a preintegrated habitable module which fits inside the EC-130E aircraft and is transported in a similar fashion to the illustrated concept.
| Aircraft Type | Cargo Mass (kg) | Range (km)* | Cargo Size (m) | Landing Surfaces | Runway (m)** |
|---|---|---|---|---|---|
| C-130: | Up to 17,600 | 3791 | 2.74H x 3.04W x 12.5L | snow/ice/hard | 1091 |
| C-141: | Up to 38,500 | TBD | 2.74H x 3.04W x 27.7L | bare ice/hard | TBD |
| C-5: | Up to 132,000 | 5525 | 2.90H x 5.79W x 37.2L (or 4.10H x 3.96W) | bare ice/hard | 2530 |
** Runway length at sea level.
It is expected that analog habitation element quality and reliability will be optimized by preintegration of much of the component hardware prior to transport to the analog mission site. The conditions present at the polar plateau site create the need to minimize the time and risks required for on-site construction of the analog elements. Preintegration of analog hardware elements to some extent is therefore necessary to reduce construction risks.
Ocean-going ships and the LC-130 aircraft provide the necessary capabilities to deliver preintegrated analog elements to the polar plateau site. These capabilities should be exploited to the advantage of the analog program to minimize construction and to simulate planetary surface habitat emplacement operations.
Methods of surface propulsion will be required to emplace analog elements at the construction site. It is assumed that vehicles will be available to move and position large elements in order to build up the complete habitation system. Historically, tracked surface vehicles, such as the Snocat and the Peter Snow Miller, have been used to move heavy equipment and to excavate snow (reference 21). A surface vehicle for operation at the altitude of the polar plateau site may require development in terms of its propulsive power system.
Deployment of appendages from preintegrated elements provides an effective method of packaging and construction for large elements such as habitats. Methods of deployment which minimize the need for specialized support equipment and tools and which minimize the risk to successful completion of the construction mission are desirable.
Preliminary requirements for habitable element constructability are:
Each analog habitat element shall be emplaced, activated, and verified operational within TBD hours after transport aircraft landing at the analog site.
Minimize the number of separate elements which must be assembled.
Minimize the number of support personnel and man-hours required for construction.
Standardize interfaces between assembled elements.
Surface transport of the habitat element is provided by a support vehicle and facilitated by skids mounted to the habitat. Berthing of habitat elements is accomplished by rigging them to pull the new element together with those already emplaced. After they are pulled together, their crew passageways and utility interfaces are connected to complete the berthing process.
An expected opportunity for systems testing, based on reference 24, is to perform an operational verification of robotic construction techniques for a preintegrated habitat element. Associated issues to be studied are the effectiveness of telerobotics for analog construction and support personnel safety during construction operations.
External systems and equipment will be exposed to the polar plateau environment, resulting in weathering and the need for maintenance. Drifting snow can cover and damage a long-term habitat; therefore, it has been suggested that elevating it on legs and lifting or moving the habitat periodically is an approach to avoiding damage from snow drifts (reference 19).
Internal systems and equipment will degrade over time and will be affected by the presence of human crews. Crew operations will result in use of the systems and the need for systems maintenance.
Critical analog habitation system functions must be maintainable on-site by the analog crewmembers to ensure crew safety and health. All analog systems should be maintainable to promote crew productivity and mission success.
Preliminary requirements for habitat maintainability are:
Analog systems functions which are necessary for crew safety and health shall be restorable after failure by on-site systems maintenance by the analog crew, without detriment to crew safety or health.
Consumables to be resupplied include human consumables such as food, clothing, work supplies, and possibly air and water. For reference, the cost of diesel fuel supplied to the South Pole Station in 1990 was estimated at $3/liter ($12/gallon) in reference 19.
Equipment to be resupplied includes spare and replacement components for analog systems and science experiments.
Stowage and some level of environmental control must be provided for the consumables and equipment both during transport and at the analog site.
Trash or other waste materials must be packaged, stored, and transported away from the analog site for reprocessing or disposal. Historically, trash disposal has included sealing in fuel drums (reference 21) and landfilling.
Preliminary requirements are:
The logistics system shall provide environmental conditioning and control during the transfer of equipment and consumables.
The logistics system shall provide the capability to transport trash and other waste materials from the analog site to approved disposal sites.
Logistics support subsystems will require specialized thermal control such as refrigerator/freezer racks, and the Antarctic environment could be used as a source of cooling for these units.
The logistics carrier is refurbished at the logistics origination site and is reused in the delivery phase of later logistics flights. Some logistics carriers may be retained at the analog site and outfitted to expand the habitable facility.
The analog habitation systems must provide acceptable living conditions for the crew and thereby enable the human physiology, behavior, and performance research which forms a major part of the basis for the defined analog mission.
Key aspects of long-term habitability include protection from environmental conditions, the capability for crewmember privacy, interior space for crew movement, visual and aural environments which enhance crew productivity, and methods for cooperative action among individuals and subgroups.
Historically, more recent Antarctic stations have better habitability than earlier outposts. Permanent structures and buildings have been built, providing long-term habitability which expeditionary tents and temporary huts could not support.
Preliminary requirements are:
Analog habitat habitability provisions shall include protection from external environmental conditions, interior free space for crew movement, the capability for crewmember privacy, visual and aural environments which meet NASA standards, and means for cooperative action among crewmembers and with remote personnel.
The health care subsystem includes both information aspects and systems aspects. Information aspects include communication among analog crewmembers as well as communication between crewmembers and remote medical specialists which will be needed to supplement the knowledge and skills of analog crewmember physicians. Medical evacuation of ill or injured crewmembers will also be dependent on communication with remote evacuation personnel.
Systems aspects of health care include the hardware, software, and supplies provided at the analog habitat to support ongoing preventive health care, diagnosis, and medical and dental treatment.
Preliminary requirements are:
The health care subsystem, in conjunction with other habitation functions shall maintain analog crew health during the analog mission.
Preliminary requirements for crew accommodations subsystems include:
Consumables shall be designed with a TBD shelf-life. Packaging and storage facilities shall accommodate the shelf-life requirements for consumables.
Crew accommodations should maximize crew productivity.
Extra calories may be needed during periods of heavy physical effort and/or exposure to cold. Antarctic explorers travelling overland on skis have used 5100 calories per person-day, with premission predictions of 8000 calories per person-day (reference 26). Analog crewmembers are not expected to consume as many calories when simulating an SEI mission, based on anticipated lower metabolic work loads and less exposure to cold.
The food management subsystem must provide nutritionally balanced, palatable foods for the analog crew for the length of their mission. Food packaging, preservation, and storage must ensure a reliable and safe food supply. Food processing, preparation, and disposal of wastes must facilitate crew operations and minimize the amount of crew time necessary for meal preparation and cleanup.
Preliminary food management requirements are:
The food system shall be designed with a TBD shelf-life requirement.
Food packaging and storage facilities shall accommodate the shelf-life requirements for the food system.
Trash management as defined here includes:
References 30 and 31 describe some of the environmental issues surrounding current waste management techniques at Antarctic stations. Sewage, solid wastes, and hazardous chemicals are examples of waste streams which must be managed. The NSF in 1988 announced plans to end open burning of solid wastes at its stations (reference 30). USAP task T-322, Waste Minimization, Treatment, and Disposal Program for McMurdo Station, was planned in 1990 to assess waste generation operations and identify waste minimization opportunities (reference 22).
Preliminary trash management requirements are:
Trash shall be removed from the analog site via the logistics and transportation systems, and shall be disposed of in accordance with applicable treaties and policies.
The trash management subsystem should minimize its mass, volume, and power requirements.
The trash management subsystem should minimize negative impacts of habitat wastes on the Antarctic environment.
Preliminary personal hygiene requirements are:
The personal hygiene subsystem waste water streams shall be compatible with the life support subsystem's waste processing capabilities.
Personal hygiene and grooming supplies shall have shelf lives of TBD length.
Personal hygiene and grooming equipment and supplies shall accommodate male and female crewmembers.
Cleansing and grooming supplies should be nonallergenic.
Habitat interior operations clothes
Linens
Habitat exterior operations suits
Clothing maintenance.
Historically, Antarctic clothing has been bulky and heavy, up to 18 kg (40 lbs) for early explorers. Current clothing is lighter, layered, and covers the entire body except for parts of the face. Thermally insulated boots are especially critical (reference 21).
Preliminary crew clothing requirements are:
Clothing cleaning and maintenance functions shall be provided.
Clothing shall remain usable for the length of the mission.
Interior operations clothes shall be designed for the range of habitat atmospheric conditions.
Exterior operations clothes shall be designed to maintain the skin temperatures of an immobile or active crewmember within their normal ranges with an environmental temperature of TBD and wind speed of TBD.
Clothing should resemble that expected for space missions.
Clothing fibers and construction should provide flame resistance without requiring special treatment during the mission.
Current remote communications in Antarctica includes high frequency radio and satellite systems for voice, teletype, and electronic mail. Many Antarctic station have commercial satellite services to enable transmission of data and telephone-quality voice. The South Pole Satellite Data Link enables data transmission and official communications from the South Pole Station to McMurdo Station and the Continental United States (reference 18).
Antarctic communications by radio frequency is sometimes difficult or impossible at certain wavelengths due to auroral "blackouts" or static electricity caused by snow blowing across a radio antenna (reference 21).
The Global Positioning System satellite network provides position and time signals for users on the Earth's surface. Other existing satellites, including polar orbiting and geostationary, may be useful in providing some remote communications capability for a polar plateau analog.
Geostationary satellites appear very near the horizon from the 82 degree south latitude used for the reference mission in this document; therefore, their usefulness may be marginal. It may be desirable to utilize a polar orbiting system to provide continuous and reliable contact with the mission control site and with emergency evacuation personnel at other Antarctic stations.
Reference 32 describes the conceptual polar orbiting Iridium communications system which is currently being studied. If deployed in the mid-1990's, this system would provide continuous global coverage for the transmission of digital voice, low rate data, and facsimile information.
Video capability between the polar plateau and other sites is not provided by low data rate systems such as Iridium. Specialized satellite links for video would be required.
In 1990-1991, the Antarctic Communications Survey, USAP task T-323 was scheduled to perform a comprehensive survey of communications resources and needs for the USAP stations and field research. Planning for an INTELSAT satellite ground station was also scheduled under this task (reference 22).
Preliminary requirements for the analog communications subsystem are:
Wireless links between analog crewmembers inside and outside the habitat
Time signal acquisition
Position signal acquisition
Emergency backup link to evacuation team
Antenna deployment and positioning
Voice, data, and video transmission from the analog to remote sites
Voice, data, and video reception from remote sites
The communication subsystem shall interface with the information management subsystem to transmit analog information and to receive outside information
The thermal control subsystem must be designed to remove waste heat from areas of high heat generation and to redistribute it to areas of lower temperature where heat loss to the environment occurs. Thermal "shorts", points of high heat loss rate, are to be avoided to prevent condensation and/or freezing of habitat internal atmospheric humidity (reference 33).
A low rate of heat loss per unit of habitat external surface area is necessary to maintain the habitat interior within the required temperature range and to prevent melting of snow on the outside of the habitat. The buildup of ice on the habitat exterior from refreezing of melted snow can cause excessive weight on the structure (reference 34). It is also important that the habitat not cause melting of the snow surface beneath it in order to keep it stable; therefore, the surface supports of the habitat element must be designed to reduce their potential thermal shorting effect.
It is desirable that the total habitat heat loss rate be no greater than the nominal rate of heat generation by personnel and equipment inside the habitat, to reduce the need for supplemental heating of the habitat interior. Off-nominal situations, such as a reduction of habitat power, will reduce the interior heat generation rate to the point that supplemental heating may be required to maintain the habitat temperature within the acceptable range.
Preliminary requirements for the thermal control subsystem are:
The internal habitable atmosphere shall be maintained within the range of TBD- TBD degrees C (TBD-TBD degrees F), and the dewpoint shall be maintained within the range of TBD-TBD degrees C (TBD-TBD degrees F) under nominal operational conditions. (This requirement impacts both the thermal control subsystem and the life support subsystem.)
A single failure of the thermal control subsystem shall not cause habitat temperatures to exceed their nominal ranges.
A dual failure of the thermal control subsystem shall not cause permanent damage to habitat systems or crew.
Supplemental heat generation capability shall be provided for habitat contingencies which reduce the normal internal heat generation rate below that necessary to maintain the habitat temperature above TBD degrees C.
The habitat thermal control subsystem should minimize the need for active heat rejection devices separate from the habitat, instead making use of the natural environment heat sink to remove excess heat at controlled rates from the habitat.
atmospheric carbon dioxide and trace contaminant control
atmospheric temperature and humidity control
atmospheric pressure and composition control
potable and hygiene water management
organic waste management
food production.
Life support consumables of air and water are readily available from the analog mission environment. At the high altitudes of the Antarctic polar plateau, oxygen enrichment and/or pressurization of the ambient atmosphere may be necessary for human habitation to prevent hypoxia.
Preliminary requirements are:
The carbon dioxide level in the habitable atmosphere shall be maintained within the range of TBD-TBD mmHg under nominal operating conditions, and within the range of TBD-TBD mmHg under contingency conditions.
The habitat atmosphere shall meet applicable NASA standards for contaminant levels.
The partial pressure of oxygen in the habitat atmosphere shall be maintained within the range of TBD-TBD kPa (TBD-TBD psia).
The concentration of oxygen in the habitat atmosphere shall be maintained within the range of TBD-TBD percent.
The potable and hygiene water supplies shall meet applicable NASA standards for contaminant levels.
Food produced by the life support subsystem shall meet applicable NASA standards for contaminant levels.
The humidity control function should minimize the amount of heat rejected to the environment in order to reduce habitat overall heat loss.
Historically, diesel generators and a nuclear power plant have been used in the Antarctic as sources of electrical power (reference 21). Limited use has been made of solar and wind power.
Preliminary requirements on the electrical power subsystem are:
It shall transmit, distribute, switch, control, invert, convert, connect, and store electrical power and energy in support of the habitat systems and crew.
The electrical power subsystem should minimize parasitic power losses in transmission, distribution, and control.
Applications for information management may include systems control and monitoring, fault management and recovery, planning and scheduling, and support to crew activities such as science experimentation, scheduling, data base utilization, word processing, mathematical analysis, programming, etc.
Preliminary requirements are:
Data types to be managed include instrumentation readings, voice, facsimile, and video.
The information management subsystem shall interface with the communications subsystem for wireless transmission of data.
All continuous waveform analog data should be converted to digital form for handling by the information management subsystem.
For the polar plateau site, the external atmospheric pressure may fall to approximately 55 kPa (8 psia) during the winter season. The habitat internal atmosphere must be maintained within the physiologically acceptable limits for crew health and productivity. The function of maintaining a difference in atmospheric pressure between external and internal environments is allocated to the habitat structure.
Also allocated to the structure is the function of reduction of air exchange between the external and internal environments. This air exchange is normally present as leakage from the higher pressure interior to the lower pressure exterior.
The structural system must support habitat systems and contents during transport, construction, and operations. The required support includes resisting gravitational, inertial, wind, and snow loads.
Historically, Antarctic habitat structures have been deployable, constructible, or preintegrated. These have been placed both above and below the surface. The U. S. Plateau Station living units were basically modular insulated plywood boxes with aluminum exterior coverings and could be joined together during surface emplacement, after unloading from an LC-130 transport (reference 21).
Preliminary requirements are:
The habitat structural subsystem shall provide the capability for atmospheric pressure differential between the habitat interior and the environment of up to TBD kPa (TBD psia) during transport, emplacement, and operations.
The structural subsystem shall provide environmental protection for habitat interior subsystems and equipment.
The structural subsystem shall provide for leveling of the emplaced habitat.
The structural subsystem shall enable loading and unloading of the habitat onto surface ships and aircraft, transport of the habitat, offloading at the emplacement site, surface transport, and emplacement.
The structural subsystem shall accommodate seismic events with TBD characteristics.
The structural subsystem shall provide for stabilization of habitable elements on the local surface.
The structural subsystem shall provide the function of anchoring and/or attachment of habitat elements to the underlying ground surface if this is determined to be necessary to meet any other requirement.
The structural subsystem shall provide for deployment of habitat external appendages required for support of habitat subsystem hardware.
The structural subsystem shall provide for the berthing/docking/connection of habitat elements with each other.
The structural subsystem shall provide for movement of crewmembers and TBD size equipment into and out of any habitat element.
The structural subsystem should be stiff enough to minimize undesirable elastic deformation and/or vibration of the habitat during all mission phases.
Research and test opportunities associated with the analog habitat structural/mechanical subsystem include:
Potential terrestrial benefits related to the analog habitat structural/mechanical subsystems include:
Issues and trades specific to this subsystem include:
Research is required into low temperature effects on lubricants, polymers, and composite materials, including bond strength of dissimilar materials (reference 4).
A habitat structural concept is shown in Figure 3.2.2.13-1 which is compatible with the transport and construction concepts described in sections 3.2.2.1 and 3.2.2.2.
The habitat surface support system consists of pads and telescoping leveling legs attached to the ends of the habitat element. During transport the surface supports are stowed to fit the transport envelope. They are extended during emplacement to raise the element off the surface and to level it.
The habitat outer shell, based on reference 36, is a skinned, self-inflating polymeric foam layer which is collapsed for transport by removing air from its interior. For shell deployment, the interior of the foam is exposed to atmospheric pressure. This causes it to inflate to its original shape, producing an elliptical foam shell the length of the habitat element. This shell provides thermal insulation and atmosphere containment within the habitat. A low pressure differential may be possible across this shell, if necessary.
The load-bearing structure is a rigid, box-shaped framework of square cross-section tubing members. Deployable structural racks are stowed inside this framework for transport, then are deployed during element emplacement after the outer shell is inflated. These racks support the habitat interior subsystems and equipment. The volume left empty when the racks are deployed is utilized as habitable free volume during analog mission operations.
The analog habitat provides interior lab space and equipment which enables a variety of physical science procedures. Included may be meteorite analysis, ice core analysis, and collection and storage of data from exterior science instruments.
Preliminary requirements are:
Functions of the physical science support subsystem shall include microscopy, sample storage and curation, data storage and processing, and TBD additional functions (chromatography, spectroscopy, chemical analysis, etc.).
Human, animal, and plant physiology, human psychology, and human performance are scientific disciplines which should be supported in the analog habitat.
Preliminary requirements for the life sciences support subsystem are:
Functions of the life science support subsystem shall include data collection and processing, sample collection and storage, experimental animal holding, and plant sample analysis.
Those systems which include components or configurations representative of flight systems may generate performance data which can be applied to flight systems development, including information on lifetimes, performance trends, and maintenance.
Other systems, which do not closely represent flight systems, may nevertheless provide general operational data which can be applied to flight systems development, if it is collected in a systematic way. Crew comments on the design and usefulness of various pieces of equipment and their functional aspects may provide insight into the needs of Lunar and Mars mission crews.
Preliminary requirements are:
Preliminary requirements for support of mission operations development are:
Terrestrial analog habitation systems were conceptualized based on a mission to the Antarctic polar plateau environment.
Research and testing opportunities within this conceptual analog were defined. Technologies needed to implement the concept were specified. Trades to be performed prior to selection of baseline systems concepts were identified.
Several major goals exist for SEI terrestrial analogs, including systems testing, human research, physical science, and mission operations simulation. The pursuit of all these goals as a group will result in a more robust analog program than the use of any of them individually.
Terrestrial environments available for SEI analogs include a broad range of conditions which may be useful in simulating either space transportation or planet surface missions. Environmental parameters have been isolated and qualitatively described for a range of terrestrial environments. Selection of an optimum environment is dependent on both the determination of the characteristics of the SEI mission to be simulated and the objectives and constraints of the terrestrial analog program.
The Antarctic polar plateau presents a valuable environment for early evaluation of some aspects of long-duration SEI missions. Logistics, communications, surface operations, systems performance, and human isolation and confinement are potential subjects for polar plateau analog research and testing. Significant science can be performed on the polar plateau by crewmembers of long-duration SEI analog missions.
Terrestrial analogs can be viewed as early, highly visible milestones for the SEI, resulting in increased public understanding and support of SEI goals. Terrestrial benefits may be demonstrated in several areas including environmental protection, food management, and automation.
Technical studies should be performed to clarify the issues associated with selecting terrestrial environments for SEI analog missions, developing analog systems, and planning analog operations.
A program plan should be developed to guide programmatic, research, and technology activities supporting SEI terrestrial analog development and operations.
The SEI should make use of terrestrial analogs as early milestones in a long-term process of preparing for the exploration of the solar system.
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