FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1963
1963 - 0973.PDF
944 FLIGHT International, 13 June 1963 Missiles and Spaceflight as well as many people from our research centers in NASA and some people from the Air Force and many people from industry, we are approaching this combustion instability problem in a sound way. And, indeed, in a particular injector which we have tested in recent runs—it is either ten or eleven; I think there has been one run since I saw the data, so eleven runs—we haven't encountered a single case of combustion instability. Yet we have run some five tests for the full duration of 150sec. "And this engine, gentlemen, is a really large engine. I saw one fire out at Edwards Air Force Base in California. We have to fire the F-l at Edwards because of the tremendous noises given off, to prevent acoustic damage. It creates a very great blast, and I think you can see why when you realize that this one engine has as much thrust as the total thrust of the present Saturn first-stage vehicle, a million and a half pounds. We were probably a little too close—at around 1,400ft, and the noise reached the threshold of pain. When the engine was through firing—and, incidentally, that day it did fire well over lOOsec—the dust started coming down and rained dust on us. It is going to be very interesting to see five F-ls at once." CENTAUR PROGRESS The design changes illustrated below are being introduced in the Centaur high-energy upper stage (two Pratt & Whitney RL-10 liquid hydrogen engines) in an effort to meet the target operational date of late 1964. The following testimony by Dr Homer E. Newell, Director of the Office of Space Sciences of the National Aeronautics and Space Administration, was given recently in hearings before the Committee on Science and Astronautics of the US House of Representatives. "The largest vehicle under development by the Office of Space Sciences is the Atlas Centaur, with the upper-stage Centaur engine fuelled with liquid hydrogen. The first development flight failed. Thereafter, an intensive design review was jointly undertaken by in-house and contractor teams leading to specific design decisions (see diagram). "Also, special ground tests have been and will be made to A Nosecone, weather shield and insulation panels redesigned B Improved fabrication techniques C 100 per cent X-ray and cryogenic testing D Intermediate bulkhead quality improved E Improved separation system F Increased ground test programme G Atlas-Centaur-Surveyor dynamic tests H Atlas configuration resolved J A-3 engine PFRT completed K Single burn early flights for reliability L Alternate chilldown cycles M Tank configuration resolved N New tank material planned O Increased tank thickness P Improved guidance system test and evaluation programme initiated Q 2.1001b (min) Surveyor capability reaffirmed The above design changes, made to the Atlas-Centaur launch vehicle, were described recently in Congressional testimony by Dr Homer E. Newell (see "Centaur Progress") establish the validity of the current design and construction. In order not to inhibit the Marshall Space Flight Center's heavy commitment to Saturn in support of Project Apollo, the Centaur project was transferred to the Lewis Research Center. The design improvements are being incorporated and preparations are uncier way for the next flight test in the third quarter of 1963." Speaking of NASA experience with Thor Agena and Atlas Agena vehicles, Dr Newell said: "NASA's single use of Thor Agena, to launch Alouette, was completely successful. The Atlas Agena performed well on Rangers 4 and 5 after failing on Rangers 1, 2 and 3. Atlas guidance aborted the first Mariner attempt. On the successful Mariner launch, a vehicle malfunction did occur but did not impede the mission. Atlas Agena performance is not considered satisfactory, and a joint Air Force/NASA intensive quality improvement programme is under way, aimed at simpli- fication and standardization of the vehicle and at increased quality control of all components." Construction of a second Centaur launch complex at Cape Canaveral began recently under the direction of the Corps of Army Engineers. Designated Complex 36B, this facility is located near the existing Centaur pad, Complex 36A, and will use the same blockhouse. "Design, development, installation and validation" of the ground support equipment required for the new complex are the responsibility of General Dynamics/Astronautics. The twin complex should be completed by late 1964 and should be able to handle an average of one Centaur launch per month. Under the direction of NASA's Lewis Research Center, the Centaur vehicle is being developed with top (DX) priority by General Dynamics/Astronautics at San Diego. "FAITH 7" FAULT TRACED According to a National Aeronautics and Space Administration statement on May 29, "problems with two connectors to an electrical amplifier" caused Astronaut Gordon Cooper to take over and control manually the re-entry of his spacecraft Faith 7 on May 16. The following details were given. The two connectors are located in the amplifier calibrator where electrical signals of various spacecraft systems are converted into commands. These commands cause activation of the hydrogen peroxide jet thrusters in the automatic control system to maintain proper spacecraft position in relation to the Earth. The spacecraft sensors include the gyroscope and infra-red horizon scanners. First, the appearance of the 0.05g panel light and later the failure of the a.c. power from the inverter signalled the problems to Astronaut Cooper. Carefully detailed post-flight examination of the spacecraft circuit revealed the following facts:— The inverter trouble was traced to an electrical power connector which, among other functions, passes the a.c. output from the inverter buss (ASCS) into the amplifier calibrator. The insulating qualities of the connector had failed and permitted the a.c. power line to earth, causing a short circuit. The inverters will not operate in the event of such a malfunction in the circuit, and the operating characteristics observed in flight were as expected for such an electrical fault. A post-flight examination of the inverters showed them to be undamaged. Corrosion was found in and around another electrical connector through which some of the 0.05g circuit passed. Presence of the corrosion indicated the possibility that moisture had collected in the area and resistance checks of the current passing through the connector indicated changing resistance as though the system were drying out. Later, tests with completely dried circuits and a new power connector showed satisfactory operation of the amplifier calibrator, including the 0.05g circuit. Introduction of small quantities of moisture to the plug resulted in actuation of the 0.05g circuit as it had done during flight. Thus, it wa$ concluded from these tests that actuation of the 0.05g circuit during the MA-9 mission probably resulted from effects of moisture in the connector. The inverter and 0.05g troubles during the mission were traced to independent electrical connectors that failed different times during the flight. There is no indication that the failures were connected other than the fact that the electrical insulation broke down in both cases. Correction of these problems (NASA concluded) will include tighter control of moisture within the spacecraft and an increase of the protection of the electrical connectors and other components from moisture.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
