1959 – Twelve Men On The Moon

by Dave Fischer

Copernicus, Eratosthenes and Project Horizon
Image Credit: NASA / GSFC / Arizona State University

The Lunar Reconnaissance Orbiter Camera team recently released this image featuring the famous crater Copernicus with its ejecta splashed across much of the face of the Moon. Copernicus and the crater Eratosthenes lie just south of Mare Imbrium. To the east of Copernicus and south of Eratosthenes lies the nearly featureless plain called Sinus Aestuum. Here, just southeast of Eratosthenes lies the location of a proposed Moon Base. In addition to the scientific value of this area, the rich ores of the Rima Bode regional dark mantling deposit lie nearby.

On 20 March 1959, Arthur G. Trudeau, Chief of Research and Development for the U.S. Army, submitted a request for the study to place a lunar outpost on the Moon. The result was Project Horizon, a plan (dated 9 June 1959) to place a military base with 10-20 men on the surface of the Moon by 1965. Full details are in Vol. I and Vol. II (pdf).

The introduction to the proposal stated that the establishment of a lunar base would:

  • Demonstrate the United States scientific leadership in outer space
  • Support scientific explorations and investigations
  • Extend and improve space reconnaissance and surveillance capabilities and control of space
  • Extend and improve communications and serve as a communications relay station
  • Provide a basic and supporting research laboratory for space research and development activity
  • Develop a stable, low-gravity outpost for use as a launch site for deep space exploration
  • Provide an opportunity for scientific exploration and development of a space mapping and survey system
  • Provide an emergency staging area, rescue capability or navigational aid for other space activity

Lunar Base
Project Horizon – Lunar Base 1965
Image Credit: US Army

Project Horizon – Rockets
Image Credit: US Army

It further stated the following, prescient about the Soviet manned capability, but extremely optimistic about the timetable for the Moon Base:

Advances in propulsion, electronics, space medicine and other astronautical sciences are taking place at an explosive rate. As recently as 1949, the first penetration of space war accomplished by the US when a two-stage V-2 rocket reached the then unbelievable altitude of 250 miles. In 1957, the Soviet Union placed the first man-made satellite in orbit. Since early l958, when the first US earth satellite was launched, both the US and USSR have launched additional satellites, moon probes, and successfully recovered animals sent into space in missiles. In 1960, and thereafter, there will be other deep space probes by the US and the USSR, with the US planning to place the first man into space with a REDSTONE missile, followed in 1961 with the first man in orbit. However, the Soviets could very well place a man in space before we do. In addition, instrumented lunar landings probably will be accomplished by 1964 by both the United States and the USSR. As will be indicated in the technical discussions of this report, the first US manned lunar landing could be accomplished by 1965. Thus, it appears that the establishment of an outpost on the moon is a capability which can be accomplished.

Underlying all of this was the traditional von Braun team approach:

paramount to successful major systems design is a conservative approach which requires that no item be more “advanced” than required to do the job. It recognizes that an unsophisticated success is of vastly greater importance than a series of advanced and highly sophisticated failures that “almost worked. “

The proposal discusses the ongoing development of the Saturn I by ARPA, expecting it would be fully operational by 1963. The Saturn I stood more than 200 feet tall, and would be superseded by the Saturn II in 1964, standing 304 feet tall. By the end of 1964, a total of 72 Saturn I rockets would have been launched on various programs of discovery, including 40 to support the manned lunar base. In order to support the full complement of 12 men, 61 Saturn I and 88 Saturn II launches would be required by the end of 1966, landing 490,000 pounds of cargo on the lunar surface. 64 launches were scheduled for 1967, landing an additional 266,000 pounds of supplies. The total cost of the eight and one-half year program was estimated to be $6 Billion.

The von Braun team thought very large indeed.

Let us know what you think. What do you want to know about? Post a comment.

Pintle Injector Rocket Engines

by Dave Fischer

We have had several queries concerning “pintle injectors” (make sure you read the last paragraph of this post), as these are mentioned in the Space-X page on the Falcon 9, where it refers to the Merlin rocket engine and the “pintle style injector“:

The main engine, called Merlin 1C, was developed internally at Space-X, drawing upon a long heritage of space proven engines. The pintle style injector at the heart of Merlin 1C was first used in the Apollo Moon program for the Lunar Excursion Module (LEM) landing engine, one of the most critical phases of the mission.

Based on the queries and the Space-X information, we went sleuthing. First, we came across the fact that TRW built the LEM descent engine, which used the pintle injector. We ran across David Meerman Scott’s blog apolloartifacts for a discussion and look at a model of the famous Lunar Module Descent Engine (LMDE). The engine was made famous by the Apollo 13 mission, where:

the Service Propulsion System (SPS) was never used subsequent to the cryotank stir/explosion. Because the extent of damage to the SPS was unknown, there was great concern at the time that collateral damage could have caused a catastrophic malfunction (if the engine was fired). Instead the LMDE was used for the return burn and subsequent course correction. Quite a famous engine.

In 2000, TRW demonstrated the TR-106 engine (pintle injector) using LOX / LH2 at NASA’s John C. Stennis Space Center . The engine generated 650,000 pounds of thrust, more than the 400,000 pounds of thrust generated by the Space Shuttle Main Engine SSME. Al Frew, vice president and general manager, TRW Space & Technology Division stated:

Most engines are designed for maximum performance and minimum weight, but we deliberately set out to develop an engine that minimizes cost while retaining excellent performance. We believe this engine will cost 50 to 75 percent less than comparable liquid hydrogen boosters. By reducing engine costs, which make up almost half of the cost of a launch vehicle, we will reduce the cost of launch vehicles and access to space for government and commercial customers.

Despite the promise the motor demonstrated, NASA canceled further work.

The pintle injector engines have a long history in the former Soviet Union. The NK-33 was the successor to the NK-15 engines used in the failed Soviet N1 Moon launcher. NK-33 have been used with the Russian Proton launch system. An interesting discussion of the Soviet Moon rocket, its engines and the NK-33 successor can be found here, along with spectacular video of the launch and explosion. Orbital Sciences has now contracted with Aerojet (owner of the NK-33 engines) to finish developing and testing the NK-33 engines, now designated as AJ26-58 for the Taurus II.

Jonathon Goff, at Masten Space Systems, had a commentary at Selenianboondocks on the 2006 Space-X change from an ablative Merlin engine to a regenerative engine. Jon states that the “engine related problems are interrelated, and that they have to do with the combination of using a high chamber pressure engine design with a pintle-injector and an ablatively cooled chamber wall.” That is, the flame produced by the cone of fuel and oxidizer hits the wall of the chamber and overheats the wall.

Included in the commentary is a simplified image of a pintle injector rocket engine, which illustrates the flow of liquid oxygen and fuel (RP-1 or liquid hydrogen) through the pintle injector into a cone shaped spray in the combustion chamber.

The replacement of the ablative chamber with a regenerative chamber eliminates the overheating.

Pintle Injector
Pintle Injector
Image Credit: Forschungsgruppe Alternative Raumfahrtkonzepte

Below left is the business end of the LEM Descent engine, showing the Pintle Injector:

Below right is an image by Warren W. Thompson at the unveiling of Space-X’s Falcon 1 at the Air & Space Museum on 4 December 2003.

Lunar Module Descent Engine
Image Credit: jurvetson on Flickr
Merlin Engine with Pintle Injector
Merlin Engine with Pintle Injector
Image Credit: Warren W. Thompson

Finally, while explaining the Pintle Injector to a friend, I realized that almost everybody who has a garden or tends a lawn has personal experience with pintles. You all use a nozzle on the end of your watering hose. Crank it down and you get a steady, narrow stream of water shooting out in a long arc. Crank it back the other way when you want to shut it off, and you get a wide, cone shaped fan spray. Now, turn off the water and look at the business end of the garden hose nozzle (please shut the water off first). There in the middle is a round pintle that moves back and forth as you crank the outer casing one way or the other. And the fan shaped spray of water with which you are familiar is what the fuel and oxidizer spray looks like inside the rocket engine. So take another look at the two images above and imagine the fan shaped spray. The only difference is that your spray of water doesn’t explosively combust and throw a rocket into space.