Bellcomm, Inc., based near NASA Headquarters in Washington, DC, was carved out of Bell Labs in 1962 to provide technical advice to NASA's Apollo Program Director. The organization rapidly expanded its bailiwick to support nearly all NASA Office of Manned Space Flight advance planning.
In a January 1968 report, Bellcomm planners N. Hinners, D. James, and F. Schmidt proposed a lunar mission series designed to bridge a gap in NASA's plans that they felt existed between the first piloted "Early Apollo" lunar landings and sophisticated Apollo Applications Program (AAP) lunar flights. The three planners declared that their Lunar Exploration Program was "based upon a reasonable set of assumptions regarding hardware capability and evolution, an increase in scientific endeavor, launch rates, budgetary constraints, operational learning, lead times, and interaction with other space programs," as well as "the assumption that lunar exploration will be a continuing aspect of human endeavor."
They envisioned a series of 12 lunar missions in four phases. Phase 1 would span the period from 1969 through 1971. The five Phase 1 missions were largely equivalent to NASA's Early Apollo missions. They would launch at least six months apart to give engineers and scientists adequate time to learn from each mission's accomplishments and problems and apply knowledge gained to subsequent missions. Phase 1 would begin with Lunar Landing Mission (LLM)-1, the historic first Apollo moon landing.
The LLM-1 Lunar Module (LM) lander would alight on a flat, relatively smooth basaltic plain known as a mare (Latin for "sea"). The maria, which appear as mottled gray areas on the moon's white face, cover about 20% of the Earth-facing Nearside hemisphere. LLM-1 and the other Phase 1 missions would each have several back-up mare landing sites.
Almost any mare would do for LLM-1, Hinners, James, and Schmidt argued, because the first piloted landing mission would emphasize engineering, not science. LLM-1 would test the LM, lunar space suits, and other Apollo systems ahead of more ambitious Phase 1 missions. If all went as planned, the LLM-1 crew would stay on the moon for 22 hours and carry out two moonwalks.
LLM-1 would follow a "free-return" flight path that would guarantee that the Apollo Command and Service Module (CSM) could loop around the moon and return to Earth without propulsion in the event that its Service Propulsion System (SPS) main engine failed en route to the moon. The SPS was meant to adjust the CSM/LM combination's course during flight to and from the moon, slow the CSM and LM so that the moon's gravity could capture them into lunar orbit, and boost the CSM out of lunar orbit for return to Earth. The Bellcomm planners noted that the free-return trajectory would greatly limit the percentage of the moon's surface that LLM-1 could reach.
The LM designed for the Phase 1 missions would be capable of delivering up to 300 pounds of payload to the moon's surface. For all five missions, this payload would include geologic tools for collecting up to 50 pounds of lunar samples for return to Earth. LLM-2 through LLM-5 would, in addition, each include an Apollo Lunar Scientific Experiment Package (ALSEP) - a cluster of geophysical experiments - for deployment on the moon.
The lunar-surface astronauts on missions LLM-2 through LLM-5 would perform geological traverses on foot to spots "several thousand meters" (that is, several kilometers) from the LM. Meanwhile, the CSM Pilot, alone in lunar orbit, would photograph the moon's surface through the CSM's small windows.
LLM-2, like LLM-1, would follow a free-return trajectory and stay for 22 hours at a mare landing site. It would, however, add a third moonwalk. LLM-3 would abandon the free-return trajectory so that it could reach a fresh crater on a mare. The crater, the Bellcomm planners explained, would serve as a natural "drill hole." Studies of both natural and human-made craters on Earth had shown that the LLM-3 astronauts would find the oldest rocks - those from farthest beneath the surface - on the crater rim. The astronauts would perform three moonwalks during a surface stay that would last longer than 22 hours but less than 36 hours.
LLM-4 would be similar to LLM-3, but would be targeted to a mare "wrinkle ridge." LLM-5, the final Phase 1 flight, would see an LM spend 36 hours at a mare site bordering a Highlands region. The Highlands of the moon, the light-colored areas on the moon's disk, are ancient cratered terrain. The LLM-5 astronauts would perform four moonwalks.
The Bellcomm planners' four Phase 2 missions would commence about two years after LLM-5 and span 1972-1973. Upgrades to Apollo hardware and operations in Phase 2 would permit in-depth exploration of specific unique landing sites selected for scientific interest. Among the operational upgrades that Hinners, James, and Schmidt proposed was alteration of Earth-to-moon flight time or time spent in lunar orbit prior to landing to permit an Extended LM (ELM) spacecraft to reach its pre-planned target site even if launch from Earth were delayed for up to several days.
The Phase 2 lunar-surface astronauts would perform six moonwalks at each landing site. The ELM could land 1300 pounds of payload. Phase 2 CSMs would carry prototype remote sensors to test their feasibility ahead of their operational use in Phases 3 and 4.
The first Phase 2 mission, LLM-6, would see an ELM spend three days at Tobias Mayer in the extensive Oceanus Procellarum mare region. The LLM-6 astronauts would deploy an ALSEP and explore on foot a sinuous rille (canyon), a dome (possible volcano), and a fresh crater with a surrounding dark halo (possible volcanic vent). LLM-7 would be similar to LLM-6, but would land at a linear rille site designated I-P1.
LLM-8 would see the introduction of the Lunar Flying Unit (LFU), a one-person rocket flyer. Bellcomm targeted LLM-8 to the Flamsteed Ring, an ancient crater mostly submerged by lava during the formation of Oceanus Procellarum. At the time Hinners, James, and Schmidt selected it, the Flamsteed Ring was suspected of being an extrusive volcanic feature called a "ring dike."
LLM-9, similar to LLM-8, would visit Fra Mauro, a site known for its domes and rilles, which were interpreted as signs of recent volcanism. Fra Mauro would later come to be seen as a large geologic unit made up of ejecta from the enormous impact that blasted out Mare Imbrium. Cone crater, a natural drill hole in the Fra Mauro Formation, would become the target of Apollo 13 (and, after that mission failed to land on the moon, of Apollo 14).
Phase 3 of Bellcomm's Lunar Exploration Program would comprise a single lunar-orbital survey mission in 1974. The mission would, for all practical purposes, mark the start of advanced AAP lunar flights. By spending 28 days (one lunar day-night period) in lunar polar orbit, an augmented CSM could pass over the entire lunar surface in daylight. A solar-powered sensor module based on a planned AAP Earth-resources observation module design would replace the LM in Phase 3. When time came to return to Earth, the astronauts would leave behind the sensor module in lunar orbit, where it would function as an independent satellite.
Hinners, James, and Schmidt explained that Lunar Exploration Program Phases 1 and 2 missions would gather "ground truth" data concerning the moon's surface. These data would enable scientists to interpret Phase 3 mission results in preparation for Lunar Exploration Program Phase 4, which would span 1975-1976.
Phase 4 would see two "Dual Launch" Lunar Surface Rendezvous and Exploration Missions. Each Dual Launch mission would require two Saturn V rockets, two augmented CSMs, an LM-derived unmanned Lunar Payload Module (LPM) carrying 8000 pounds of cargo, and an augmented ELM carrying one LFU.
LLM-10 and LLM-11 together would make up the first Dual Launch mission. LLM-10 would deliver an unmanned LPM to either Hyginus Rille or the Davy crater chain. The LLM-10 crew, orbiting the moon in their augmented CSM, would remotely pilot the LPM's final approach to the landing site to ensure that it could set down within 100 meters of a predetermined target point. Before returning to Earth, the LLM-10 astronauts would "photo locate" the landed LPM from lunar orbit to aid the follow-on LLM-11 crew in finding it. They would also release a science subsatellite into lunar orbit.
LLM-11 would see two astronauts wearing advanced "hard" (non-fabric) space suits land their augmented ELM near the pre-landed LPM for a two-week stay. They would draw on the LPM's four tons of cargo to conduct in-depth exploration of their complex landing site.
LPM cargo would include surface transport systems: specifically, one LFU and a one-man, 2000-pound Local Scientific Survey Module (LSSM) moon rover. Other LPM cargo would include a spare hard suit; a core drill attached to the LPM for obtaining a 100-foot drill core; an LSSM-transportable core drill for obtaining 10-foot cores at scattered sites; spare life support consumables for LLM-11's ELM; and an advanced lunar-surface geophysical station with a 10-year design life.
Hinners, James, and Schmidt selected the Marius Hills as the landing site for LLM-12 and LLM-13, their second Dual Launch mission pair and the final missions of their Lunar Exploration Program. Marius Hills was popular with planners for its many domes and other features of possible volcanic origin.
The Bellcomm planners anticipated that, after the LLM-13 crew returned to Earth, even more ambitious AAP moon missions would commence. They were, of course, incorrect; it became clear soon after they completed their report that lunar exploration would not become "a continuing aspect of human endeavor."
The earliest Apollo landing missions (Apollo 11, Apollo 12, Apollo 13, and Apollo 14) were roughly equivalent to Bellcomm's LLM-1, LLM-2, and LLM-3; Apollo 15, Apollo 16, and Apollo 17 were, however, shaped by the certain knowledge that Apollo lunar exploration would soon conclude. They became unlike any of Bellcomm's proposed missions as NASA sought to accomplish as much lunar exploration as possible before political support for the moon program ran out.
Reference
"A Lunar Exploration Program - Case 710," N. W. Hinners, D. B. James, and F. N. Schmidt, TM-68-1012-1, Bellcomm, January 5, 1968.
