The Scientific Context for Exploration of the Moon: Interim Report (2006)

The committee also identified several related themes and goals that are needed for implementation of the science themes and goals.

Successful implementation of science in a program of human exploration is highly dependent on a cooperative relationship between the two communities. To acquire lessons learned from past experience, the SSB Committee on the Human Exploration of Space (CHEX) conducted a study of science prerequisites, science opportunities, and science management in the human exploration of space.¹ For science management, CHEX looked at the Apollo, Skylab, Apollo-Soyuz, and Shuttle/Spacelab programs to determine what organizational relationships, roles, and responsibilities contributed to superior outcomes.

CHEX found that human exploration offers a unique opportunity for science accomplishment and as such should be viewed as part and parcel of an integrated human exploration-science program. CHEX developed three broad management principles, which, if implemented, would improve the probability of a successful synergy between science and human exploration:

1. Integrated Science Program—The scientific study of specific planetary bodies, such as the Moon and Mars, should be treated as an integral part of an overall solar system science program and not separated out simply because there may be concurrent interest in human exploration of those bodies. Thus, there should be a single NASA headquarters office responsible for conducting the scientific aspects of solar system exploration.

2. Clear Program Goals and Priorities—A program of human spaceflight will have political, engineering, and technological goals in addition to its scientific goals. To avoid confusion and misunderstandings, the objectives of each individual component project or mission that integrates space science and human spaceflight should be clearly specified and prioritized.²

3. Joint Spaceflight/Science Program Office—The offices responsible for human spaceflight and space science should jointly establish and staff a program office to collaboratively implement the scientific component of human exploration. As a model, that office should have responsibilities, functions, and reporting relationships similar to those that supported science in the Apollo, Skylab, and Apollo-Soyuz Test Project (ASTP) missions.

Consistent with the principles enunciated above, CHEX found a definitive correlation between successful science accomplishment and organizational roles and responsibilities. In particular, the quality of science was enhanced when the science office (SMD now) controlled the process of establishing science priorities, competitively selecting the science and participating scientists and ensuring proper attention to the end-to-end cycle ending in data analysis and publication of results.

Robotic technology. The combination of surface mobility and manipulation is a key requirement for extracting science on the lunar surface, both during precursor and sortie missions. For autonomous/semi-autonomous robotic operations on the lunar surface, gaps exist in current robotic capabilities and should be addressed in order to enable achievement of science goals. These challenges include development of the following capabilities:

• Long-distance navigation and access:

  • Command of a single vehicle to access and maneuver on all lunar terrain types, such as disturbed lunar soil, steep rim slopes, and craters and basins; cover long distances; and carry/deploy a payload.

  • Robust operation for extended periods of time, including functioning during the 14-day lunar night.

  • Navigation in shadowed regions, such as those found in the polar craters.

  • Visualization of the environment for human supervision/telepresence.

• Instrument placement and manipulation:

  • Dexterous placement of a science instrument precisely on a designated target with a required contact force, while accounting for lunar gravity and environmental constraints.

  • Interchange of end-effectors needed to achieve contact measurements.

  • Robust acquisition and manipulation of multiple science samples and transport to a location of interest.

  • Manipulation of sensors for active experimentation, such as drilling and placement of instruments beneath the lunar surface.

Instrumentation. Some types of in situ and laboratory measurement technology have not yet achieved their potential to accomplish scientific goals. For use on both robotic and human missions and for returned samples, development of the following instrumentation capabilities poses a challenge:

• In situ determination of the radiometric age of a crystalline igneous or impact melt with a precision of 10 percent or better of the age, which would address fundamental issues in lunar and planetary geochronology without sample return, preserving return mass for more sophisticated analysis.

• In situ measurement of cosmic ray exposure ages, which is essential to establish more recent dates.

• In situ routine microanalysis (major elements, mineralogy) and imaging at the 10-micron scale, for fields of view of a few millimeters.

• In situ measurement of minor and trace elements for gram-sized samples.

• High-resolution remote sensing, at the scale of tens of centimeters, to allow precise targeting of some types of samples, and to inform the crews and ground support of the types and distributions of materials present at the site.

• Upgrading of analytical instrumentation for sample analyses in the curatorial facilities and in principal investigators’ laboratories.

Capability is also needed for rapid-analysis contact analytical tools to facilitate decision making during human and robotic geologic or geophysical traverses. Hard landers, such as penetrators that emplace instruments, will require shock-hardened variants of the above and other instruments.

Apollo experience demonstrated both the complexity of planning lunar surface operations and the benefits of doing so. The planning started long before flights and included determination of science objectives, landing site selection, astronaut science training, science team selection, traverse planning, sampling strategies, geophysical station development (ALSEPs), full-up mission simulations, and data analysis preparations.

A similar range of preparation will be essential for implementation of the Vision for Space Exploration. Much of what was learned by hard experience on Apollo can be efficiently incorporated into future planning. Obviously a lot of the detail will have to, and should, await a date closer to mission implementation; however, certain aspects can be initiated now with relatively low investment. These include considering:

1. Sites on the Moon that would prove most productive for scientific investigation;

2. The type of missions—sortie and/or outpost—that can best satisfy high priority science objectives;

3. The range of crew mobility needed; and

4. The optimum mix of robotics and human activity that best meets the science objectives, taking into consideration operational constraints (this should consider pre-human robotic missions).

Two areas are of special interest for early study:

1. Landing site selection. NASA’s plans to return to the Moon necessarily involve the selection of surface exploration sites. Such sites will be selected based on a number of factors. Safety will undoubtedly be a prime consideration, but today’s technology and capability basically open up the entire Moon to exploration. Where one explores then becomes a matter of which sites best provide the venues for accomplishing exploration goals. These will include science, ease of access, build-up of an outpost or base, potential for development of in situ resource utilization (ISRU), commercial potential, and so on. Many of the science goals elucidated in this interim report depend critically for their successful accomplishment on getting to specific lunar landing sites. Undoubtedly a given site might satisfy many of the requirements of the different goals. And, in fact, site selection might have to satisfy a fundamental requirement to maximize meeting multiple requirements.

The identification of specific candidate landing sites requires more time than was available for this interim report.

2. Surface mission operational planning. Apollo experience demonstrated that the most valuable resource on the Moon is time. There is inevitably more to be done than time allows. For example, astronauts were constantly under pressure to “move on to the next station.” Many opportunities to examine discoveries in more detail were missed (e.g., orange soil on Apollo 17, “genesis” rock on Apollo 15). Things that went wrong took time away from meeting the timelines (e.g., a stuck drill). It is necessary to devise methods to conserve astronaut time, doing robotically those things that do not take greatest advantage of the human capability to observe, make decisions, and use manual dexterity to advantage. NASA should undertake an examination of Apollo missions with an eye toward identifying time-saving opportunities.

The typical Apollo-type sortie mission of 2 to 3 days is too short to accomplish the level of scientific investigation now merited by our improved understanding of lunar science. If, however, sortie missions are a selected mode for early Vision missions (currently, sorties up to 7 days are under consideration), then planning is needed to increase their efficiency. A possible mode is to precede the human flight with robotic rover precursors in which the rover, similar to the Mars Exploration Rover (MER) on Mars, conducts reconnaissance and identifies high-priority traverse locations for astronaut investigation. The rovers on Apollo missions 15 to 17 demonstrated the benefit of mobility; their use was limited primarily by safety and life-support supply considerations. Analysis of the extent to which such

constraints can be relieved on future missions is necessary. Similarly, telerobotic operations during a human mission might add immeasurably to mission efficiency.

The attributes of the lunar outpost concept for purposes of scientific investigation deserve study. The potential advantages are increased time for detailed geologic study, geophysical instrument emplacements and traverse surveys, preliminary sample selection, follow-up on results obtained on earlier flights to the outpost, and utilization of logistics previously emplaced. An outpost would warrant a greater investment in terms of reusable resources, for example, a multi-mission rover with resuppliable on-board life support and sophisticated analytical instrumentation. Such a rover could be used in automated mode between outpost visits. Many of these attributes were being considered in the 1960s as follow-ons to the initial Apollo missions but were, obviously, never executed when missions after Apollo 17 were canceled.