Filling a Gap: Bellcomms 1968 Lunar Exploration Program

Bellcomm, Inc., based near NASA Headquarters in Washington, DC, was carved out of Bell Labs in 1962 to provide technical advice to NASAs 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 NASAs lunar exploration schedule between the first piloted Apollo lunar landing and later, more advanced Apollo Applications Program (AAP) lunar 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.

To bridge the gap between early Apollo and AAP, 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 missions 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 moons 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 argued, because the first piloted landing mission would emphasize engineering, not science. LLM-1 would test the LM, lunar space suits, and other moon 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 design 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 carry an Apollo Lunar Scientific Experiment Package (ALSEP) geophysical station for deployment on the lunar surface. Astronauts of missions LLM-2 through LLM-5 would also perform geological traverses on foot to spots several thousand meters (that is, several kilometers) from the LM while the CSM Pilot in lunar orbit photographed the moons surface.

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 CSMs Service Propulsion System (SPS) main engine failed en route to the moon. The SPS was meant to adjust the CSM/LM combinations course during flight to and from the moon, slow the CSM and LM so that the moons 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 moons 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, 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, the light-colored areas on the moons disk, are ancient cratered terrain. The LLM-5 astronauts would perform four moonwalks.