Jun 25 1959

From The Space Library

DISCOVERER IV failed to achieve orbit.

At the second meeting of the Research Steering Committee on Manned Space Flight, held at the Ames Research Center, members presented reports on intermediate steps toward a manned lunar landing and return.

Bruce T. Lundin of the Lewis Research Center reported to members on propulsion requirements for various modes of manned lunar landing missions, assuming a 10,000-pound spacecraft to be returned to earth. Lewis mission studies had shown that a launch into lunar orbit would require less energy than a direct approach and would be more desirable for guidance, landing reliability, etc. From a 500,000 foot orbit around the moon, the spacecraft would descend in free fall, applying a constant-thrust decelerating impulse at the last moment before landing. Research would be needed to develop the variable-thrust rocket engine to be used in the descent. With the use of liquid hydrogen, the launch weight of the lunar rocket and spacecraft would be 10 to 11 million pounds.

If the earth orbit rendezvous concept were adopted, using Saturns to launch Centaurs for the lunar landing mission, nine Saturns would be needed to boost nine Centaurs into earth orbit for assembly to attain escape from earth orbit; three more Centaurs would have to be launched into earth orbit for assembly to accomplish the lunar orbit and landing; two additional Centaurs would be needed to provide for return and for the payload. The total of 14 Saturn/Centaur launches would be a formidable problem, not even considering the numerous complex rendezvous and assembly operations in space. The entire operation would have to be accomplished within two to three weeks because of the limitations on storing cryogenics in space.

Research would be needed on propulsion problems; on reliable, precisely controlled, variable-thrust engines for lunar landing; on a high-performance, storable-propellant, moon-takeoff engine; on auxiliary power systems; and on ground operations. Reduction of the ultimate payload weight was extremely vital, and more accurate information was needed on power and weight requirements for life support, capsule weight and size, and the exact scientific payload.

Lundin felt that a decision on whether to use the Saturn or Nova approach should be made as soon as possible since it would affect research and intermediate steps to be taken.

During the Research Steering Committee meeting, John H. Disher of NASA Headquarters discussed the lunar mission studies under way at the Army Ballistic Missile Agency (ABMA):

• ABMA had a large and competent group concentrating primarily on the lunar mission.
• Velocity and thrust requirements agreed well with those determined by the Lewis Research Center.
• ABMA was recommending a Saturn C-2 launch vehicle having a 2million-pound-thrust first stage, a 1-million-pound-thrust second stage, and a 200,000-pound-thrust third stage. Another launch vehicle six times larger than the Saturn C-2 was also being studied for direct ascent.
• ABMA was interested in obtaining a NASA contract to study the Saturn C-2 vehicle.
• Two approaches were being studied for the manned lunar landing, one refueling in earth orbit and the other assembling separately landed parcels on the moon for the return flight (lunar surface rendezvous).
• The ABMA schedule dates were unrealistic considering present funding and problem complexities.
• Orbit control and landing point control experiments were urgently needed, possibly with Mercury-type capsules.
• Large-scale controlled reentry experiments at lunar reentry velocity should begin as soon as possible.

The Committee agreed that studies should continue on the direct ascent versus earth orbital assembly and that Lewis should become more familiar with ABMA studies, while concentrating on the Nova approach. It was also suggested that the High Speed Flight Station look into the operational problems of assembly in orbit.

A report on a projected manned space station was made to the Research Steering Committee by Laurence K. Loftin, Jr., of the Langley Research Center. In discussion, Chairman Harry J. Goett expressed his opinion that consideration of a space laboratory ought to be an integral and coordinated part of the planning for the lunar landing mission. George M. Low of NASA Headquarters warned that care should be exercised to assure that each step taken toward the goal of a lunar landing was significant, since the number of steps that could be funded was extremely limited.

Alfred J. Eggers, Jr., of the Ames Research Center told the members of the Research Steering Committee of studies on radiation belts, graze and orbit maneuvers on reentry, heat transfer, structural concepts and requirements, lift over drag considerations, and guidance systems which affected various aspects of the manned lunar mission. Eggers said that Ames had concentrated on a landing maneuver involving a reentry approach over one of the poles to lessen radiation exposure, a graze through the outer edge of the atmosphere to begin an earth orbit, and finally reentry and landing.

Manned steps beyond Mercury, he said, should be:

• The use of the Vega or Centaur boosters to put a manned satellite into an orbit with a 50,000-mile apogee, carrying two men for two weeks to gain experience beyond Mercury with reentry techniques and extended manned space flight applicable to the lunar mission.
• The use of the Saturn booster in manned flight to the vicinity of the moon and return, putting two men in a highly elliptical orbit, with an apogee of up to 250,000 miles or even one pass around the moon before heading back to earth. The flight time would be about one week, providing experience similar to that of the manned lunar mission, including hyperbolic reentry to earth. A close, direct view of the lunar surface by man would support lunar landing.
• The use of the Nova or clustered-engine Saturn booster for a lunar landing and return. Two men would carry out this one-week to one-month expedition.

Eggers recommended that the same type of return capsule be used in all these missions to build up reliability and experience with the spacecraft before the lunar landing mission. Unmanned space probes should also be used to investigate certain factors related to the success of the lunar mission: polar radiation, lunar radiation, grazing reentry, lunar surface characteristics, and micrometeoroids.

The Committee unanimously agreed that investigation of a grazing reentry was necessary and would require an unmanned space probe. NASA Centers would look into experiments that might be launched by a Scout or Thor-Delta booster. Committee members would check to be sure that the basic programs in the Office of Space Flight Development space sciences programs covered the requirements for investigation of the other factors of special interest to the manned lunar mission.

Members of the Research Steering Committee determined the study and research areas which would require emphasis for manned flight to and from the moon and for intermediate flight steps:

• Lunar mission studies:

More work would be required on determining "end" vehicle weight, life-support requirements, scientific payload requirements and objectives, exploring the possibility of using the "end" vehicle configuration in intermediate flight steps, booster requirement analysis, and Mercury stretch-out capabilities.

• Direct ascent versus assembly in earth orbit:

Lewis to continue Nova studies and become familiar with Army Ballistic Missile Agency (ABMA) work on the rendezvous approach, High Speed Flight Station (HSFS) to study operational requirements for assembly in earth orbit, and recommended for ABMA study of assembly in earth orbit.

A reliable, precisely controlled, variable-thrust engine for lunar landing. A storable propellant lunar takeoff rocket. Storage of cryogenics in space (emissivity, absorptivity, etc.).

• Structural work:

A study of molybdenum coating life at higher temperatures, a contract for test specimens to expedite NASA research, emphasis on research on ablating materials suitable for low heating rates, and study of combination radiation and ablation techniques.

• Life support ( short term up to one month): contract study proposed.

• Space suit development:

HSFS to study desired specifications.

• Guidance system studies focused on the lunar mission:

Development of light but sophisticated onboard computers, data-smoothing techniques and effects on midcourse guidance accuracies, effects of gravity anomalies on initial instrumentation, terminal guidance system including retrothrust programming, and error analysis and energy requirements for the entry corridor on return to earth.

Minutes, Research Steering Committee on Manned Space Flight, June 25-26, 1959, attached summary pages 1-2.