Pete Conrad begins his descent to the lunar surface during Apollo 12, a near-twin of Bellcomm’s mission LLM-2. 
NASA
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 mission series designed to fill a gap which they felt existed in NASA’s lunar exploration schedule between the first piloted Apollo lunar landing and later, more advanced Apollo Applications Program (AAP) flights. The trio declared that their plan 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, Apollo Lunar Landing Missions, would span the period from 1969 through 1971. The five Phase 1 flights would launch at least six months apart to give engineers and scientists adequate time to learn from each mission’s accomplishments and apply knowledge gained to subsequent missions. They would begin with Lunar Landing Mission (LLM)-1, the first Apollo 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.
For LLM-1 and the other Phase 1 missions, the LM would have several back-up mare landing sites. Almost any mare would do for LLM-1, Hinner, James, and Schmidt contended, because the first mission would emphasize engineering, not science. LLM-1 would test the LM, lunar space suits, and other exploration 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.
The LM used in the five Phase 1 missions would carry up to 300 pounds of payload to the lunar surface. For all five missions, this payload would include geologic tools for gathering up to 50 pounds of lunar rocks and dirt for return to Earth. LLM-2 through LLM-5 would, in addition, each deploy an Apollo Lunar Scientific Experiment Package (ALSEP) geophysical station. LLM-2, LLM-3, LLM-4, and LLM-5 astronauts would perform geological traverses on foot to spots “several thousand meters” from the LM while the CSM Pilot in lunar orbit photographed the moon’s surface and operated remote sensors.
LLM-1 would follow a “free-return” flight path that would guarantee that the Apollo Command and Service Module (CSM) and attached LM would loop around the moon and return to Earth in the event that the CSM’s Aerojet-General-built 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 help to ensure crew safety but would greatly limit the percentage of the moon’s surface that LLM-1 could reach.
LLM-2 would, like LLM-1, be restricted by a free-return trajectory and a stay-time of 22 hours at a mare landing site. The LLM-2 astronauts would, however, carry out three moonwalks and deploy the first ALSEP, thus enabling them to accomplish more scientific exploration than the LLM-1 astronauts.
LLM-3, the third mission of Lunar Exploration Program Phase 1, would abandon the free-return trajectory so that it could attempt to reach a fresh crater on a mare. The crater would, Hinners, James, and Schmidt explained, act as a natural “drill hole” that would expose ancient rocks from deep inside the moon for sampling. 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, visible as 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 – which they called the Lunar Surface Exploration Missions – would commence about two years after LLM-5 and would span t1972-1973. Modifications to Apollo hardware and procedures in Phase 2 would permit in-depth exploration of specific unique sites selected for scientific interest. Hinners, James, and Schmidt proposed, for example, that NASA alter Earth-moon flight time or time spent in lunar orbit prior to landing to permit the LM spacecraft to reach a specific site even if launch from Earth were delayed up to several days.
Phase 2 CSMs would carry a selection of remote sensors to test their feasibility ahead of Phases 3 and 4. The lunar-surface astronauts would perform six moonwalks at each site and draw upon up to 1300 pounds of landed payload.
Apollo 15 astronaut James Irwin works beside the mission’s Lunar Roving Vehicle, the first to reach the moon. Beginning with Apollo 15, NASA deviated from Bellcomm’s proposed Lunar Exploration Program. NASA
The first Phase 2 mission, LLM-6, would see an Extended LM (ELM) spend three days at Tobias Mayer in Oceanus Procellarum. 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 the expedition to the Flamsteed Ring, an ancient crater mostly submerged by lava during the formation of the extensive mare Oceanus Procellarum. At the time Hinners, James, and Schmidt selected it, however, it was suspected of being a “ring dike,” an extrusive volcanic feature. LLM-9, similar to LLM-8, would visit Fra Mauro, a site known for its potentially volcanic domes and rilles.
Phase 3 would comprise a single Lunar Orbital Survey and Exploration Mission in 1974. By spending 28 days (one lunar day-night period) in lunar polar orbit, an augmented Apollo CSM could pass over the entire lunar surface in daylight once. A solar-powered sensor module based on a planned AAP Earth-resources observation module would replace the LM. The CSM would deploy a scientific subsatellite and leave the sensor module behind in lunar orbit to continue scientific studies after the astronauts departed for Earth.
Phase 1 and 2 missions would gather “ground truth” data. These would allow the Phase 3 mission’s results to be interpreted in preparation for intensive surface exploration in Phase 4.
Phase 4′s Lunar Surface Rendezvous and Exploration Missions (1975-76) would each 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 of two such “Dual Launch” missions in Phase 4.
LLM-10 would deliver an unmanned LPM to either Hyginus Rille or the Davy crater chain. The LLM-10 crew, orbiting the moon on board their augmented CSM, would remotely control 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 and release a lunar-orbiting science subsatellite.
LLM-11, the second mission of Phase 4′s first Dual Launch pair, would see two astronauts wearing advanced “hard” space suits land their ELM near the 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 with tanks of extra propellants and a one-man, 2000-pound Local Scientific Survey Module (LSSM) moon rover. Other cargo would include a spare hard suit; a core drill attached to the LPM for obtaining a 100-foot drill core; an LSSM-transportable drill for obtaining 10-foot cores at scattered sites; additional life support consumables for the LLM-11 augmented ELM; and an advanced geophysical station with a 10-year design life.
Hinners, James, and Schmidt targeted the second Dual Launch expedition (LLM-12 and LLM-13), the last missions of their Lunar Exploration Program, to the Marius Hills, a site popular with Apollo planners for its many domes and other features of possible volcanic origin. They anticipated that, after the second Phase 4 landing crew returned to Earth, even more ambitious moon missions – perhaps using new-design spacecraft, not the CSM and LM – would follow.
They were, of course, incorrect; lunar exploration did 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 lunar exploration would soon be ended. They became unlike any of Bellcomm’s proposed missions as NASA sought to accomplish as much lunar exploration as possible before time and money ran out.
References
“A Lunar Exploration Program – Case 710,” N. W. Hinners, D. B. James, and F. N. Schmidt, TM-68-1012-1, Bellcomm, January 5, 1968.
