Figure 1. Rankings of candidate primary phase instruments according to 7 criteria.
Wendell W. Mendell,
Director, ISU93 Design Project
Solar System Exploration Div.
NASA Johnson Space Center
Houston, TX 77058 USA
The International Space University (ISU) conducted a study of an International Lunar Farside Observatory and Science Station (ILFOSS) as a Design Project activity during its 1993 summer session at the University of Alabama at Huntsville. The ILFOSS Design Project provided a learning experience for young professionals working in an unusual multidisciplinary and multinational environment while striving for in-depth analysis of a topical issue during an intense ten weeks. The resulting study describes an evolutionary program culminating in the establishment of a very advanced lunar scientific facility. Program elements and schedule derive from the requirement to perform frontier science in the fields of astronomy and astrophysics. No lunar base is assumed. The report includes scientific instrument selection, mission architecture, space transportation, lunar surface infrastructure, operations analysis of instrument installation by astronauts, multinational political organization, cost estimates, risk assessment, technology evaluation, and communication networks. The ILFOSS Final Report gives insight into the views a multinational group working in an apolitical environment on the problems of international cooperation in space.
During its sixth annual summer session from June 21 to August 27, hosted by the University of Alabama at Huntsville, the International Space University (ISU) conducted a study of an International Lunar Farside Observatory and Science Station (ILFOSS)1. The ILFOSS study served as one of the 1993 Design Projects, a part of the standard curriculum wherein students work as a team on a program plan for a potential future space mission chosen by the ISU Board of Directors. ISU Design Project topics are deliberately structured as multinational, multidisciplinary endeavors set in the future, beyond the normal planning horizons of the world's space agencies. The Design Project activity is intended to expose young space professionals to complex group interactions and to decision-making in an environment where knowledge can be incomplete. Experiences in the Design Project simulate those encountered by space professionals in leadership and policy-making positions.
The problem statement was kept very general, forcing the students to deal with many "soft" issues such as defining goals and objectives and setting priorities among competing mission activities. The students were commissioned to conduct an interdisciplinary study on the establishment of an remotely operated international scientific facility on the surface of the Moon. The purpose of the lunar facility was:
ILFOSS was intended to be a long-term, multinational cooperative effort. The theme of the study was a focus on scientific objectives rather than lunar base design. Participants in the lunar facility were assumed to be governmental entities but private participation was allowed if the political and organizational analysis indicated such a solution.
The ISU summer sessions are 10 weeks of intense multidisciplinary information transfer spanning all aspects of space studies. Lectures, both introductory and advanced, are given by the academic faculty in 9 Departments: Space Policy and Law; Space Business and Management; Space Engineering; Space Architecture; Space Life Sciences; Space Physical Sciences; Space Resources and Manufacturing; Space Humanities; and Satellite Applications.
The ISU attracts a multinational and multidisciplinary collection of young professionals, in the early stages of their careers, who want to gain insight into the complex decisions that will be facing the leaders of the world's space programs in the next generation. This year 100 students from 28 countries attended the ISU.
The curriculum has three components: Core Lectures, intended to establish a common base of knowledge among all students about space activities and technologies; Advanced Lectures, intended to provide students with current information on new research related to their specialties; and Design Projects, intended to provide an active, participatory process wherein students can exercise their technical skills and apply knowledge acquired in the academic lectures.
Since the Design Project is one element of the academic experience at ISU, the students work on it only part time for the ten weeks. Formally scheduled work time does not appear until the second half of the session. Thus, time for project deliberations must be found amid a hectic schedule of required academic lectures and workshops. The technical task groups are not formed until the third week, and they consist of volunteers who then face the challenge of turning a multinational collection of strangers into a coherent team. In addition, the skill mix among students in the project is not optimized to address the problem statement.
Very general statements of high-level requirements must be transformed into project definition by a task group council called the Management Interface Group (MIG). The project management job of the MIG is difficult because its membership rotates on a weekly basis to give more students experience in the decision process and to guarantee participation by non-native-English speakers.
Why formulate such an Herculean task? If the ISU is to develop leaders for tomorrow's space programs, then the young, highly trained but narrowly focused specialist must become aware of the unstructured, multidimensional environment in which decisions are made. Some of these dimensions are technical, some are political, some are bureaucratic, and (increasingly) some are cultural.
The Design Project exercise is experiential as well as tutorial. Students are asked to work in a truly multidisciplinary environment where a policy analyst or a sociologist might have strong input to an engineering design problem. For many students, the ISU will be their first encounter with a multicultural workplace where the technical approach to a problem is unfamiliar. They are involved for the first time in debates over program requirements and scope at the highest level rather than being restricted to narrow technical questions. These process issues are a very significant part of the Design Project experience.
The tangible product of an ISU Design Project is a report. The outside world judges the value of the ISU in terms of its technical content. In fact, the students judge themselves by the same measure. Frequently, quality is equated with the level and wealth of detail, but the quality of the product lies as much with the conception of the plan as it does with any technical tour de force that might reside within the report. In practice, the final reports of the Design Projects have been thoughtful and complete because the students always mount an extraordinary effort to produce a high quality product despite formidable time constraints and resource limitations.
Success depends on access to adequate technical information, the imposition of the "right" amount of organizational structure on the project by the faculty without reducing the experience to homework assignments, and the constant monitoring of student task groups by the faculty and staff to mitigate destructive personal tensions. However, this year - as in other years - the most important component of the success of the Design Project was the dedication and ingenuity of the students themselves.
The ILFOSS study was directed by one full-time faculty and four half-time faculty. The faculty was supported by three full-time Project Assistants, each of whom had been an ISU student. Additional support came from the academic ISU faculty, the academic Department Assistants, and various visiting lecturers who generally chose to stay a few days to work with the students.
At the end of the first week of ISU the students selected which Design Project to join. In ILFOSS each was assigned initially to an Orientation Group. The groups were constructed from the student data base so that each (as far as possible) was a heterogeneous mixture of nationality, discipline, and gender. Each group was asked to exchange opinions on appropriate uses of the Moon, particularly whether lunar surface activities should be limited to scientific investigations or broadened to include human presence and commercial development. Another discussion topic was the "correct" balance of humans and robots in science investigations in space. After one week each group prepared a ten-minute presentation to the project participants.
The Orientation Group exercise accomplished three objectives.
First, the discussions exposed differences of opinion on the contentious issue of the role of humans in space. In past years, debates have erupted during the projects over what is realistic and what is "science fiction" and have been disruptive to the cohesiveness of the effort. In the 1993 session, these problems were worked out before initiation of the technical work.
Secondly, the technical task groups that ultimately perform the design study have to organize themselves. Self-organization can be disconcerting to students from some cultures where hierarchies and job functions are always strictly defined. Since the group dynamic initially manifests itself through discussion and negotiation, students weak in English find themselves at a disadvantage in the development of group leadership, organization, and goal definition. The Orientation Groups help alert all the students to the problem of domination by native English speakers in developing a group's position on issues.
Finally, many students do not read orientation materials before arrival and may not be familiar with the basic issues of the project. The Orientation Groups introduce the problem statement and provide context for subsequent technical work.
Task Groups. At the beginning of the third week, each student volunteered to join one of 6 Task Groups. Each Task Group had responsibility for technical analysis and design of some aspect of the project.
The Scientific Experiment Evaluation and Design Selection (SEEDS) Task Group was responsible for defining the scientific objectives and the instruments developed within the program. Under the ground rules of the project, this group set the primary requirements. A Mission Design group was responsible for defining launch vehicles, designing landers and orbiters, designing the communications architecture, and constructing the mission scenarios with timelines. A Lunar Facility Design (LUFAD) group dealt with all the lunar surface infrastructure, although the design of the scientific instruments was led by SEEDS. Life Sciences handled all issues associated with the human crew on the surface. In practice, the division between the groups was fluid. The major science instruments were collaborations between SEEDS and LUFAD, and the surface habitat was a product of Life Sciences and LUFAD.
A Policy and Management (PAM) group dealt with the issues of international collaboration, management, and budget. This group set important boundary conditions on the scale of the project and on its mode of implementation. Due to a lack of policy students at ISU93, the policy and business functions were lumped together to create a critical mass in the task group. Unfortunately, the marriage was not a happy one because the two disciplines have few common points of reference. Even though the students did not always work as a team, they produced a thorough and thoughtful discussion of the issues.
The group responsible for Risk Assessment and Technology Evaluation called themselves the Watchdogs. They tracked the decisions and designs in all other groups and offered assessments as to realism and self-consistency. Their chapter in the final report evaluates risk of program failure in technical, political, and economic terms. They also discuss the technologies that require development work to enhance probability of success. None of the students in the Watchdogs had experience with risk assessment prior to ISU, but all seemed to enjoy the job of maintaining the project overview.
Management Interface Group. In a project as complex as the ILFOSS, each Task Group requires information from other Task Groups and, in turn, generates information required by others. In addition, the Design Faculty needs to track progress and identify choke points. These functions were performed by a Management Interface Group (MIG).
Each Task Group appointed a representative to the MIG. The MIG met twice a week to review progress and to document interface requirements. The membership rotated so that no one person represented his/her group for more than two meetings. This arrangement gave more students the experience of the multidisciplinary interaction and helped to avoid dominance of decision-making within the project by strong personalities. In addition, it encouraged non-native English speakers to take responsibility for representing the views of their group.
Since the membership of the MIG changed each week, maintaining the continuity of the project was a concern. Therefore, with each voting representative from a Task Group came the next week's representative as a nonvoting observer (and to serve as an alternate). In addition, the meeting was chaired by a Faculty Director to maintain a consistent format and decision methodology.
I chose this project decision process to be "parliamentary" where decisions are reached by consensus rather than to be "executive" as in the usual Project Manager system. The process worked satisfactorily, but progress in establishing requirements was not as efficient as one would like.
When the MIG identified technical issues which had to be resolved by more than one group, a "tiger team" composed of members from affected groups was formed to generate a report on the optional solutions to the problem and to report back. Time constraints in the study required these tiger teams to complete their work between meetings.
Schedule. The Task Groups began work three weeks before the end of the Core Curriculum. Although their days were taken up by lectures, they found enough time to flesh out the major issues and to produce a preliminary scenario. Following a break at the end of the Core, the ISU reconvened on July 27; and the Design Project Preliminary Review was held on July 31. On August 14, the Final Technical Review was held, after two weeks during which the Design Project shared time with the Advanced Curriculum lectures. The next week was devoted to cleaning up the final technical details and writing the report. Inputs from the 62 students were coordinated by a Report Committee and a (almost) complete draft of the Final Report was in the computers by midnight, Friday, August 20. Following four days of editing, correcting, and compiling, the report was reproduced rapidly and handed to students on August 27, graduation day.
The following summary of the ILFOSS Final Report is not inclusive of all the material in the report but should serve to convey the major themes. In some cases, I feel obliged to set context for the material or to comment on it. I will try to confine my remarks in subsections entitled Prologue to distinguish them from report content. Within the narrative, I may occasionally add a comment, which I will enclose in brackets.
Obviously, it is difficult to completely partition commentary from reportage. The subjects that I choose to summarize will indicate a point of view. However, I will attempt to separate the students work from my opinions to the best of my ability.
Methodology for selecting instruments. Given that the ILFOSS program was to be derived from the requirements to perform frontier observations in the fields of astronomy and astrophysics, the students derived the scientific elements of the project by addressing the following questions in sequence;
Advanced Instruments. From answers to the first three questions, the students identified eight potential instruments for a lunar surface observatory. Using numerical rankings of scientific return, value of placement on the farside of the Moon, technological feasibility, and cost, two instruments were chosen for the advanced lunar facility (Fig. 1): a very low frequency radioastronomy array (VLFA) and an optical interferometer (OI).
Figure 1. Rankings of candidate primary phase instruments according to 7 criteria.
The VLFA was based on a concept suggested at a NASA-sponsored workshop in 19883. The receiver consists of 280 independent dipole elements distributed over a 17-km circle on the lunar surface. Each element has its own small power supply, signal processing electronics, and data communication capability. Each element sends data to a central station, which combines the signals with appropriate phase relationships to create a virtual antenna with an effective diameter of 17 km. The VLFA will be capable of making observations at frequencies from 1 to 30 MHz with an angular resolution of approximately 0.6 mrad at the upper frequency and approximately 17.5 mrad at the lower. Observations at such low frequencies are not possible from Earth, and the lunar VLFA should open up a new universe of observable plasma phenomena when shielded from terrestrial interference by the body of the Moon.
The optical interferometer (OI) consists of 3 1.5m-diameter telescopes placed on the circumference of a circle of 100 m radius around a central station. Light received from the telescopes is directed to the central station where is it is combined using optical delay lines to form interferograms. The optical path must be stable during an observation to dimensions on the order of a tenth of a wavelength (~50 nm for visible light). In other words, the telescopes, the central station, and the lunar surface constitute an optical bench; and the extremely low level of seismic activity on the Moon becomes a critical condition for operation of the instrument. When operating as an interferometer, tracking is done with the secondary mirrors in the optical systems to minimize vibration. The initial alignment of the OI is very critical and requires a surface crew to deploy and set up the instrument. The OI is operated from Earth subsequently.
Only a small fraction of the field of view of each of the telescopes is extracted to be sent to the central station. Consequently, each telescope is designed to perform as a stand-alone instrument and collect data independently using the remainder of the field of view. Each telescope hosts a different instrument for this purpose: a CCD imager/photometer; an ultraviolet spectrometer; and a polarimeter. As an interferometer, the three telescopes must track the same object; and measurements by the independent instruments are limited to the field surrounding the primary object.
An interferogram is created at the detector in the central hub only when beams from two telescopes are combined such that the distance to the observed object is the same for both. The distance from an object in the sky is the same for all the telescopes only when the object is positioned at the local zenith. An optical delay lines in the central station can correct for optical path differences up to 30 meters otherwise. This capability limits the optical interferometer to observations within 11° of zenith. With only 3 telescopes contributing to a measurement, the OI cannot actually image the sky but can perform high-resolution (~3 nanoradians) astrometry along baselines defined by pairwise combinations of the telescopes.
Preliminary instruments. For political as well as technical reasons, a viable program must include early small-scale successes. Although the characteristics of the lunar environment appear to be ideal for astronomy - at least to our current level of understanding - no long term observations have ever been made from the lunar surface to verify the conclusion and to identify major issues associated with design and operation of telescopes. For example, the thermal environment is known to be challenging to the designer; but various proposed solutions for maintaining instrument optical performance have not been tested on the Moon. Mobility of lunar dust is a major question when optical surfaces must remain clean. From a political point of view, program success is threatened if more than a decade passes without tangible accomplishments.
To satisfy these criteria, two robotic instruments will be landed on the lunar farside early in the program at the proposed site for the advanced facility. Each will be capable of performing significant scientific research as well serving as a testbed for technology to be utilized in the advanced instruments. A 1m-diameter steerable telescope would be used to perform deep (i.e., long signal integration time) surveys of the sky in ultraviolet wavelengths, to perform long integration (made possible by the slow lunar rotation) on specific objects of astrophysical interest, and to search for supernovae in distant galaxies. A second lander would carry a small version of the VLFA. Five dipole elements would be deployed by microrobots to a distance of 100 m from the lander, where the central station would be located. Both of these landed instruments would be operated remotely from the Earth.
Precursor science. Site selection, site certification, and landing navigation accuracy are critical mission parameters which cannot be supplied from the current lunar data base. A lunar polar orbiting precursor mission can meet these program needs at modest cost and also can serve to collect scientific information for lunar science. An instrument complement suggested for the orbiter included a high resolution stereo imager, a visible/near-infrared mapping spectrometer, a laser altimeter, a gamma-ray spectrometer, a lunar gravity mapping experiment, a magnetometer, an electron reflectometer, a photometer (for detecting a levitated dust layer), a low frequency radio receiver (to study emissions from 100 kHz to 30 MHz), an ion mass spectrometer, and a thermal emission spectrometer. Alternate experiments mentioned include a microwave radiometer, an x-ray spectrometer, a neutral particle mass spectrometer, and a radiation dosimeter.
Opportunistic science. The students scrutinized the ILFOSS program for opportunities to perform scientific experiments that might not be related to the major thrusts of astronomy and astrophysics. Candidate payloads were considered whenever the experiment had minimal impact on accomplishment of the mission objectives and was appropriate to the lunar setting. An ideal package would be small, have low mass, and require no power or data link. Although not all ideas met these criteria exactly, interesting concepts were proposed in the fields of lunar geoscience, meteorite/cosmic dust studies, life sciences, magnetospheric physics, and material sciences. For example, life sciences students proposed a passive biostack for monitoring long term radiation effects on organisms or biological materials. The biostack consists of a sandwich-like arrangement of radiation detectors, between which are placed films containing monolayers of inert biological organisms or materials. The biostack would be carried to the lunar surface with one of the early instruments and later retrieved by the crew installing the optical interferometer.
Advanced Phase Experiments. Although the study concerned itself only with a program extending to the installation and operation of two major astronomical instruments, other candidate experiments were discussed and considered for possible augmentation of the lunar facility. The instruments described were a large optical telescope, a very large millimeter-wavelength array, a gamma ray telescope, and a large liquid mirror transit telescope.
Precursor Phase. Three years after the decision to begin the program, the precursor spacecraft would be launched into lunar polar orbit on an Ariane 4 (class) vehicle. The primary mission would last four months during which sufficient data would be collected to select the facility site on the farside of the Moon. Data useful for lunar science would continue to be collected in a extended mission phase.
Preliminary Phase. Approximately one year following the (successful) launch of the precursor orbiter, a communications satellite is placed into a halo orbit about the Moon-Earth L2 libration point aboard a Delta II (class) launcher for the purpose of establishing a link to the lunar farside. Within a year, the preliminary phase small dipole array is set down at the selected site to begin radioastronomy observations. The launch vehicle will be an Ariane 4 (class) or a Japanese HII (class). Approximately one year later, the steerable small optical telescope will be landed in the same vicinity as the small radio array, using the same lander design and a similar launch vehicle. The preliminary phase instruments will operate for approximately 7 years for evaluation of technology for lunar surface operations. Both landers will carry navigation beacons so that subsequent lunar surface elements can be landed very precisely relative to one another. In addition, the landers will carry dust detectors to measure and evaluate the hazard to instruments from lunar dust ejected at high velocities during landing of spacecraft. The information on ejecta is critical to the placement and sequence of landings in the primary phase.
The development and successful operation of a lunar lander with a 500-kg payload capacity will be a significant milestone for the ILFOSS program. In addition to the symbolic value of a successful return to the Moon, the missions are of a scale which can be afforded by a number of the world's spacefaring nations. Therefore, the missions can be designed and flown independently with a minimum of complications with management interfaces. The common threads will the participation in the farside facility, utilization of common resources such as communication and navigation aids, and the international collaboration in the scientific observations. Although some of these connections may seem trivial, they are very important in maintaining a viable international collaboration at the political level. The next phase is much more complex organizationally and will require much good will and confidence to accomplish.
Figure 2. Schedule of major ILFOSS missions and decision points
Primary Phase. Shortly after the successful operation of the preliminary phase instruments, a decision will be made to proceed with the most complex and the most expensive part of the ILFOSS program. Approximately seven years after that decision, a rapid series of launches to the Moon will establish the primary phase instruments.
The first launches will establish the communications system. Two comsats in the L2 libration point will carry advanced laser communication technology for relay of data to comsats in geostationary orbit. The lunar satellites also support radio frequency communication for use during the periods of human presence on the surface. The link will be available continuously.
Approximately, one year later the Very Low Frequency Array (VLFA) will be launched to the Moon on an upgraded Titan IV (class) vehicle and will land autonomously. Two rovers will be deployed to distribute 280 dipole elements across the 17km-diameter site. Each rover can deposit dipole elements autonomously but is also capable of teleoperation from Earth or by a crew on the lunar surface. In the teleoperated mode, the rovers can be used for site certification and for exploration.
The launcher/lander combination gives a capability to land 3 Mg of payload on the Moon. Although this Class II lander is a new vehicle, the engine technology is based on that utilized in the earlier Class I (500 kg capacity) lander. The Class II lander is used to deliver a power supply for the crew habitat and to deliver the optical interferometer.
Approximately six months after deployment of the VLFA, the establishment of the optical interferometer begins with the landing of a 16 Mg habitat near the edge of the deployed VLFA (i.e., ~9 km from the VLFA lander). Since the mass of the habitat is at the upper limits of available launch capacity, a 2.7 Mg power supply for crewed operation must be launched separately one month later and landed within 100 m of the habitat. Next, two launches of the Class II landers place the optical interferometer elements approximately 500 m from the habitat. The two landers with the OI elements also carry a crew rover. Once the OI is down safely and the crew rover is known to be operational, the crew will be launched and will land approximately 10 km from the habitat and the OI. The separation distance was chosen to safeguard the OI elements from impacts by lunar surface debris ejected during the crew landing and particularly crew ascent. However, the distance lies at the upper limits of the capability of an astronaut in a spacesuit to walk to the lander from the habitat. The measurements done in the preliminary phase on ejecta size distribution and velocity may allow designers to decrease the 10 km separation.
Both the landed habitat and the crew return vehicle fall in the 20 Mg payload class (on the lunar surface), requiring approximately 120 Mg to be launched into low Earth orbit (LEO). Since no current launch vehicle has this capacity, the students considered two alternatives. On one hand, an upgraded Energiya could launch as much as 200 Mg into LEO. On the other hand, a rendezvous in LEO between a 20 Mg shuttle payload and a 100 Mg Energiya payload would suffice. Either scenario demands investment in the maintenance of Energiya capability because there is some uncertainty as to the current status of the program and no guarantee in its continuation. [The real lesson is that human involvement in lunar activities requires investment in large launch capability or in permanent space infrastructure to support deep space missions.]
The ILFOSS study describes organization and operation of the scientific facility but does not analyze any missions after the installation of the optical interferometer. The farside facility could support more instruments and other types of scientific investigations. Missions to perform maintenance at the facility could be part of future operations. These issues are briefly discussed in a concluding section.
Site. A site was required on the farside of the Moon, at least 30° from the ±90° selenographic meridians to prevent low frequency terrestrial radio interference from contaminating the astronomical observations. The site should be relatively flat and featureless on a scale of 50 km to accommodate the quite large area required for the VLFA and allow line of site communication. An equatorial site was preferred to permit observations of the entire sky. However, higher latitudes are preferred from the standpoint of thermal design of the instruments. As a modest compromise, a range of latitudes ±20° was established.
No feature of the site should make it prone to or susceptible to seismic activity since the optical interferometer requires extreme stability during observations. Nothing about the site should compromise launch and landing safety. As a secondary requirement, preference would be given to sites of geologic interest or to sites with useful mineral resources.
Although existing photography and other information on the lunar farside is quite poor, two candidate sites were discussed. An area in the large, filled crater Tsiolkovsky (17°S, 129°E) south of the central peak seems suitable. The filled crater Aitken (17°S, 173°E) has no central peak and may also qualify.
Robotic operations. As much as possible, delivery of equipment and operation of the facility is designed without the need for human presence. Instruments are landed autonomously, deployed automatically or with teleoperation, and controlled with transmitted command sequences. Only the optical interferometer requires a crew for its precise alignment.
The preliminary phase consists of two (or more if desired) deliveries to the surface using a lander/launcher combination capable of setting down a 500 kg payload. The launcher can be one of several possibilities, but the lander must be developed. Particularly crucial is technology for a throttleable engine. The expensive engine development is amortized by using the same technology in larger landers employed in later phases. Neither of the preliminary phase instruments discussed in the report utilize the entire payload capacity of the system, opening the possibility for other experiments to piggyback on the mission.
The Preliminary Very Low Frequency Array uses the dipole element design intended for the primary phase instrument. However, only five elements are set out 100 m from the central station on the lander using microrovers. Total instrument mass is 100 kg. The operation begins observations at the very low frequencies of interest to the scientific community. Thus, the Preliminary Phase instrument serves as a testbed for the advanced instrument with simplified deployment and operation.
The Preliminary Phase Optical Telescope has a 1m diameter primary mirror and is steerable. It mass is 400 kg. The telescope is operated aboard the lander using the communication link to Earth via the libration point relay satellite.
All landers carry radio beacons and become navigation markers defining the site of the facility. All preliminary phase instruments are self-contained, relying only on the communication relay satellite. The Primary Phase VLFA instrument using a larger lander capable of delivering a 3 Mg payload to the lunar surface. As mentioned above, the engine technology is derived from the smaller lander to reduce development cost.
Two rovers onboard the lander are lowered to the surface automatically and begin deployment of the 280 dipole elements after checkout of systems. The deployment takes most of one lunar day (~12 Earth days) to minimize power requirements. Although the rovers are programmed to perform their task automatically, their programming can be modified or overridden from Earth. A video link provides the operators on Earth with information on progress of the deployment and any unexpected obstacles. This capability make the rovers useful for scientific investigations or site surveying after the deployment. Power for the rovers comes from radioisotope thermal generators.
Figure 3. Schematic of the human mission in the primary phase.
Human operations. An analysis of the installation of the optical interferometer indicated that astronauts were required. The human mission requires 5 landings at the site within a period of less than 6 months using 7 Earth launches. Each lander must be put down in a specific order at a specific location. The sequence was described above in the Mission Scenario (cf. Figure 3).
Installation of the optical interferometer will require approximately 25 working days on the lunar surface by crew in space suits (EVA). An EVA consists of no more than 8 hours of work outside by a pair of astronauts. One pair works in the habitat while the other pair works on the surface. A 42-day mission is divided into 6 workweeks of 6 or 7 days each. Every workweek is followed by a day of rest when no duties are scheduled. The rest periods coincide with lunar noon when lighting and thermal conditions are difficult, with sunrise and sunset when long shadows make work difficult, and at lunar midnight. Since the no Earthshine is available for night EVAs, lights will be turned on at the work area.
Two landers carrying components of the OI will be set down approximately 500 m from the habitat, where the instrument can be assembled. This work area can be reached easily by walking, but the distance of 10 km to the crew ascent vehicle is covered using a crew rover at the beginning and the end of the mission. The rover is attached to one of the landers carrying the OI. The rover is lowered to the surface automatically and driven by teleoperation to the crew landing site to pick them up. The crew rides in the rover to the habitat to prepare it for operation.
An attachment for the rover in the form of a forklift is carried on the other lander for the optical interferometer. The astronauts attach the forklift to the rover in order to carry the OI components from their landers to the nearby assembly site.
Surface habitat. The surface habitat consists of two nested, concentric cylinders. After landing, the inner cylinder can be extended to double the interior habitable volume. The cylinder can be retracted for added radiation protection during solar particle events. The deployed internal volume is 187 m3, and the mass is 16 Mg.
Interior pressure will be maintained at 70 kPa, the value onboard the Shuttle prior to EVA, in order to avoid the lengthy decompression protocols associated with the spacesuit at 37 kPa. The recommended life support system includes closed oxygen and water revitalization. A standby power level of 3 kW is provided by RTG's onboard. Operating power of 15 kW during crew occupation is supplied by a separately landed power module employing solar arrays.
At the end of the mission, the external power module is repackaged to preserve the solar arrays. The habitat is set into the stowed configuration and put on standby power for possible future reuse. The crew rides to the ascent vehicle on the rover and launches to Earth on a direct trajectory. An Apollo-type capsule was selected for the crew return vehicle.
For the first 35 years of the Space Age, major space endeavors were linked to the larger foreign policy objectives of the two dominant spacefaring nations, the United States and the Soviet Union. The end of the Cold War, although a positive event, has nevertheless created much uncertainty, including insecurity regarding the future of ambitious space plans. The primary objective of ILFOSS - advancement of the scientific and technological understanding of humankind through astronomical research on the Moon - is ambitious and, by its nature, falls into the purview of governmental activities.
Given the global "space recession", it is not immediately obvious that governments would be eager to support the ILFOSS program. Although active advocacy for the program will be necessary, care must be taken not to oversell it. One sure path to political failure is to advertise it as all things to all people. An honest presentation of benefits must emphasize the scientific advantages and the technical feasibility of the plan. The scientific worth of lunar-based astronomy has been expounded by credible scientific panels both in the U.S. and in Europe.
Unfortunately, scientific benefit - while necessary - is probably not sufficient to ensure political acceptance of the endeavor. The scientific arguments must be buttressed by demonstrations that participants will reap technological - and therefore economic - gains. An additional incentive peculiar to political analysis is the need to develop international mechanisms for cooperation and for trust in an increasingly disordered world. In other words, a major benefit of the ILFOSS program may well be the building of a sense of community among the participating nations.
The political and legal environment of the project will be shaped by its participants. An analysis of the space policies and the histories of spacefaring nations indicates that the major powers will find attractive roles within the program. Minor space powers and even nations without programs should be able to participate in a collaboration which could take on international symbolic attributes similar to the Olympic Games. Scientific collaborations among nations are common and do not involve the high political stakes associated with economic agreements or military treaties. Therefore, the formal agreements can be forged with flexibility to enhance program success.
Crew selection will be an important symbolic political act. The report suggests one member from each of the major spacefaring regions: North America, Europe, the former Soviet Union, and the Asian-Pacific region.
Management structure. The choice of management structure for ILFOSS will be shaped by the nature of the various phases, the past experiences in managing international cooperation, the abilities of the participants to contribute, and the perception of national interest among the partners. Previous international collaborations have taught that projects should be well-defined with self-contained phases, should have explicit technical and political objectives, and should be true partnerships with equitable sharing of decision-making.
The early activities in ILFOSS are modest in scope and can be managed at the level of national space programs with a minimum of formal structure required. However, the focus on the final goals must be maintained by some supranational entity to maintain the sense of international cooperation. An appropriate structure might be similar to the Interagency Consultative Group (IACG), which coordinated studies of Halley's Comet and now oversees the Solar Terrestrial Science Project. The IACG coordination is largely informal, taking advantage of the collaborative culture of the international scientific community.
The final mission, the installation of the optical interferometer, changes the nature of the program dramatically. All other elements are taken to the Moon on robotic spacecraft and are operated remotely. The OI requires 7 launches within a few months, 4 of which are associated with a human mission. The scope and expense of that phase will require international partnerships and must be managed with much stronger coordination. Hopefully, the earlier phases of the program will have contributed toward a stable political and fiscal environment in the project.
Scientific utilization of the preliminary phase instruments probably will be done through the Principal Investigator (PI) model. However, the primary phase instruments will be regarded as international facilities similar to observatories. A managing organization will be set up to evaluate scientific proposals for observing time, to schedule the instruments, and to operate the facility. The model for this organization is the Space Telescope Science Institute.
Cost estimation and funding. Cost estimation must be done very carefully for a new program. It produces a number by which the proposal is quickly judged, yet its accuracy is rarely assessed. Precision of the estimate is dependent on the level of detail and on the quality of information about the program. [In an ISU Design Project the level of detail is uneven and the information developed is rarely cross-checked for quality.]
The accuracy of the estimate is highly dependent on the methodology chosen. Three main techniques commonly used in the space community are cost by analogy, parametric cost estimation, and engineering cost estimation. After considering these methodologies carefully, the students chose cost by analogy because the lack of detail makes the other methods unusable. Cost by analogy is best when comparison with existing systems is available. In our case, no existing systems fit well the project as a whole. Launch systems could be priced, but other elements of the study had to be estimated by comparison with other studies which adds uncertainty.
With these caveats, the estimate for the project came to $26B over 20 years. This number is approximately what was spent by the world's space programs in the single year 1992. Interestingly, the primary (third) phase of the project represented 94% of the total cost, with most of that going to the human mission. The peak spending rate was $2.5B in the (single) year 2010. Since this rate is comparable to what the U.S. spends currently on the Space Station project, the ILFOSS requirements seem to fall within the bounds of feasibility. The weighting of the costs toward the end of the program suggest that a major decision to continue must be made after completion of the preliminary phase. An analysis of space-related expenditures by the world space programs indicates that an international program the size of ILFOSS could be supported in the time frame proposed.
Prologue. The ISU students have a very strong desire to produce a product realistic enough to have some lasting value. The scientific desire for the ultimate instrument and the engineering desire to attain ultimate performance is usually balanced in a study by setting cost and schedule limits. Cost analysis is always an element of an ISU Design Project, but iteration of the technical design based on budget considerations is never achieved. Invariably, the technical design converges very shortly before the final draft of the report is due. In fact, the final report often reflects slightly different parameters in different sections!
The quality of information input to the cost estimation tools is not very good, and the resulting cost estimates would not be suitable for constraining the design in any but the grossest aspects. Nevertheless, the continuous collection and evaluation of cost information during the project does promote restraint.
Another tool to check for realism is an independent internal group responsible for continuously evaluating the scenario for risk, both technical and political. In current NASA parlance they might be called a Red Team. This group - who referred to themselves as the Watchdogs - also evaluated technologies to ensure that the technical solutions proposed were appropriate for the time frames in which they appear in the schedule. Technology evaluation is an important product of any study because it identifies investments in development that will lower the risk of any future implementation of such a project.
The Watchdogs tracked every group in the project and gave feedback to the project in all the technical reviews and in the MIG meetings. They contributed a major chapter to the report, which I can only highlight in this paper.
Risk Analysis. The Risk Group was very concerned about the political and programmatic risk associated with the human component of the mission, given the high cost and high complexity compared with any other phase. They successfully lobbied for an explicit decision point after the preliminary phase to proceed with the human mission. They concluded that human presence was unlikely to be justifiable solely on the scientific requirements. The project should consider a marketing strategy and a programmatic structure designed to achieve a political consensus for human participation based on a vision of future human presence on the Moon. In addition, the program objectives that do not require human participation should be clearly demarcated so that they could be achieved even if the human mission was canceled.
The program should keep a clear focus on the principal scientific objectives and avoid destroying the consensus with addition of other goals to further "justify" the activity. A clear, simple structure for international involvement is best even though the complex human mission will require more formal organization among the participants. Unambiguous criteria for success should be developed for the Preliminary Phase because technical success in the simpler early phases is absolutely crucial to maintaining participation in the later phase. Scientific utilization of the established facility should be managed through an independent international organization.
Various assumed launch vehicles may not be available in the time frames required. The Ariane 4 is scheduled to be phased out, and the Chinese C-Z3 and the Japanese HII are still under development. However, the Russian Energiya is crucial to the human mission. The Energiya has not flown in several years, and the maintenance of the capability is uncertain. The Risk Group recommended an investment in the maintenance of capability to ensure Russian involvement in the Primary Phase landings.
Fault trees and Failure Modes and Effects Criticality Analyses (FMECA) were constructed for the technical design and mission scenarios, but they are too detailed to be repeated here.
Technology Evaluation. Technology options were rated to the NASA Technology readiness Level scale for all phase of the program. Unfortunately, the report does not contain a summary discussion of the technologies requiring the longest lead time in development. The lowest levels of readiness were given to robotic technologies associated with site survey and preparation, installation of the primary phase instruments, and setting up the habitat. The design of the dipole elements (particularly long-lived batteries) and the design of the interferometer were areas of concern. The students also discussed reliability of landing and ascent systems, particularly the crew return vehicle after a long storage time on the surface.
The 1993 Design Project for the International Space University was carried out in an unique multidisciplinary, multinational environment. The student participants, although not specialists in program planning, were a cross-section of bright young professionals who represent future leadership of the world's space efforts. These students were directed by experienced space professionals from North America, Europe, the Soviet Union, and Japan. The Design Project was structured in such a way as to maximize and broaden student participation in decision processes. The very short time frame of the study also placed severe constraints on in-depth consideration of some issues and precluded iterations that would have improved the consistency of the program plan.
On the other hand, the diversity of the disciplinary backgrounds of the participants provided an unusually broad analysis of the issues. The risk analyses are unusually candid. Although the students debated the merits of including humans in the scenario and decided to do so, the issue was critically examined throughout the project.
The ILFOSS study represents a thus far unique discussion of the implications of requiring a lunar-based observatory with the most advanced instruments possible. Scientific requirements were kept paramount in the program design. Human participation in the program was derived from those requirements. Yet, in the final analysis, the question arose whether scientific requirements alone suffice to create political support for human presence in space. The students were not antagonistic toward human exploration of space, but they did believe that a decision to send humans to the planets was a major financial and philosophical investment and had to be debated on its own merits in a context of future aspirations of humanity.
This study is valuable in that it is the product of a multinational group, attempting to characterize a truly international program. It is therefore free of a number of constraints that are automatically imposed on studies from national agencies. The conclusions reached and the reasoning processes used by ISU student body may give insight into the views of space exploration from the world community, into the acceptability of applications of technology, and into the institutional mechanisms required for true international cooperation in space.
In the section entitled "International Lunar Farside Observatory and Science Station", this paper borrows heavily from the ILFOSS Final Report1, which (except for the Faculty Preface) was written entirely by the students of the 1993 ISU session. In particular, most of the tables and all the figures have been extracted from the Final Report. I also wish to acknowledge others of the ISU faculty who supported this effort, particularly Larry Lemke (NASA), Robin Laurance (ESA), Byron Lichtenberg, David Kendall (CSA), Ralf Westerkamp (DLR), Tyler Bourke, and Jean-Christophe Terrillon.
1. International Space University (1993) International Lunar Farside Observatory and Science Station, Final Report of the 1993 ISU Design Project, W. W. Mendell, Director. International Space University, Cambridge, MA, USA, 442pp.
2. Mendell, W. W. (1993) Project Guide for the International Lunar Farside Observatory Design Project. International Space University, Cambridge, MA, USA, 22pp.
3. Burns, J. O., N. Duric, S. Johnson, and G. J. Taylor (1989) A Lunar Far-Side Very Low Frequency Array. NASA CP-3039. 88pp.