Sickness to Health
Agena's woes were by now chronic. The Gemini Agena target vehicle (GATV) was pacing the program by mid-1965, prompting GPO to consider removing the first production model, GATV 5001, from its job as a test vehicle so it could be used in Gemini VIII.2 All such plans went up in smoke with the explosion of GATV 5002, which ignited the most demanding piece of engineering detective work in the entire Gemini program. Efforts to cure Agena's ailments spanned more than four months, much of it on a three-shifts-a-day, seven-days-a-week schedule.3
An hour after the Agena failure of 25 October 1965, Mission Director William Schneider had left Houston for Florida, where Colonel John B. Hudson, SSD Deputy Commander for Launch Vehicles, had called a meeting of a subpanel of the Agena Flight Safety Review Board for the 26th.* The subpanel members had learned enough from telemetry data to list the tasks to be done: find out why the Agena had failed and what the fixes would entail for design, performance, and schedule; decide if it would be possible to use GATV 5001 and how long it would take to get it ready for launch; and begin cutting red tape that might slow the work.4
♦Present at the meeting were Schneider, Jerome Hammack, Alfred Gardner, Scott Simp-kinson (GPO Manager of Test Operations), John A. Edwards (NASA Director of Gemini Flight Operations), Merritt Preston (KSC Director of Launch Operations), Ernst R. Letsch (Gemini Launch Systems Directorate, Aerospace Corporation), and Lieutenant Colonel L. E. Allen (Commander, SLV-3 Division, 6555th Aerospace Test Wing).
Lawrence A. Smith, Gemini Manager for Lockheed, had already sent the taped record of telemetry signals to the plant in Sunnyvale, California, where W. R. Abbott took charge of the failure-search team. Most likely causes of the disaster were a "hard-start" backfire or an electrical short; Abbott's group soon narrowed its search to the engine as the more probable source of trouble. After reporting to Major General Ben Funk's full Agena Flight Safety Review Board, Hudson took his subpanel to Sunnyvale on 1 November; they agreed with Abbott's analysis that a hard start (similar to an automobile engine backfire) had been the cause and that it had resulted from fuel being injected into the firing chamber before oxidizer.5
The problem was rooted in NASA's original specification for a Gemini target vehicle able to start and stop its main engine five times during a mission, in contrast to the Standard Agena's two-start engine. This 150 percent increase in demands on the engine at once raised the problem of fuel and oxidizer economy. In the two-start engine, the oxidizer began flowing first, while a pressure switch restricted fuel flow until a given amount of oxidizer had reached the firing chamber. This was known to enhance the engine's starting characteristics, but it was also wasteful. Oxidizer leaked through before engine firing, and some continued to flow after shutdown; the oxidizer would be gone long before the fuel ran out. So Lockheed accepted a proposal by the engine subcontractor, Bell Aerosystems Company, to remove the pressure switch and thus allow fuel to enter the chamber first.6
Abbott concluded that in space the presence of fuel in the thrust chamber (perhaps in considerable quantity) had caused the engine to backfire when the oxidizer reached the chamber, causing an explosion. When Funk's review board met in Los Angeles on 3 November to make tentative plans for an engine requalincation program, Abbott presented his findings, which were discussed the next day.'
But Abbott's and Hudson's groups were not the only ones working on the problem. At NASA Headquarters, Associate Administrator Robert Seamans told George Mueller to form a NASA review board to look into all aspects of the failure, both technical and managerial. Mueller appointed MSC Director Robert Gilruth co-chairman of a Gemini Agena Target Vehicle Review Board and asked Air Force Major General Osmond Ritland to serve with Gilruth.* 8
And down at Cape Kennedy, Lockheed's Wulfgang C. Noeggerath was working with MSC engineer Horace E. Whitacre to pinpoint the cause of the failure. Unsure that the two of them could explore the matter in the depth needed, Whitacre suggested that Lockheed spon
*Board members were Seymour Himmel (Lewis), George Detko (Marshall), Colonel William C. Nielsen (SSD), Colonel Quenten A. Riepe (6595th Aerospace Test Wing), Morton Goldman (Aerospace), John Bailey (MSC), and Robert H. Gray (KSC).
sor a symposium of rocket experts from around the nation. Noeggerath convinced his superiors that it was a good idea.9
The two-day symposium began on 12 November, with 19 scientists and engineers in attendance.*'« Noeggerath and Whitacre told the visiting experts that the most likely cause of the Agena explosion had been a premature engine shutdown. Engine firing had produced severe oscillations and mechanical damage. Temperature decreases had indicated fuel spillage. When electrical circuitry failed, the engine stopped, but a valve that controlled tank pressure as fuel was being used remained open. As fuel stopped flowing, pressure built up in the tanks, which ruptured and destroyed the vehicle—a planned flight safety precaution. Whitacre and Noegerrath also reported that the engine had not been tested at simulated altitudes higher than 34 000 meters, since no one believed that the environment above that level made any difference for engine firings.
Although Abbott's backfire theory accounted for the oscillations that had triggered the explosion, not everyone agreed that a single cause was enough to explain what happened. But the symposium could come up with nothing better. On 15 November, it recommended to SSD that engines should be modified so oxidizer entered the chamber first and should be tested at simulated altitudes closer to where Agena would be working—above 76 000 meters, n
Funk now formed a "super tiger" team of three senior engineersf to review everything that had been found about the explosion and to suggest some answers to the NASA review board. The three agreed with oxidizer starting and with firings at simulated altitudes above 76 000 meters. They also wanted Bell Aerosystems to conduct ground ignition tests for data on engine-firing characteristics. The super tigers presented these recommendations at a meeting in Houston on 20 November,tt then to the Gilruth-Ritland review board, which approved them. Lockheed announced the formation of a Project Surefire Engine
♦Symposium attendees: S. M. King and D. D. Thomas (Aerospace), E. G. Haberman (Air Force Rocket Propulsion Laboratory), Charles E. Feiler (Lewis), Henry O. Pohl and Whitacre (MSC), D. D. Evans and J. H. Rupe (Jet Propulsion Laboratory), F. D. Sullivan and D. M. Wyck-off (Aerojet-General Corporation), T. F. Reinhardt and Craig M. Schmidt (Bell Aerosystems), Jack R. Hahn and R. S. Levine (Rocketdyne Division, North American Aviation, Inc.), J. J. Kappl (The Marquardt Corporation), R. F. Sawyer (Princeton University), and J. L. Grubbs, Jerome Salzman, and Noeggerath (LMSC).
+The super tiger team consisted of Bernard A. Hohman (Group Director, Gemini Launch Systems Directorate, Aerospace), Colonel John Hudson, and L. Eugene Root (president of Lockheed Missiles & Space Company).
tiMathews presided at the meeting, which included Gardner, Smith, Letsch, Schneider, Bailey, Hammack, Colonel Jean A. Jack (Deputy Chief of Staff, Test, Arnold), W. von Lunkhuysen and Frederick A. Boorady (Bell Aerosystems), L. T. Barnes (ARO, Inc., Arnold contractor), George Low (Deputy Director, MSC), Joseph F. Shea (Apollo Program Manager, MSC), Willis Mitchell (Vehicle and Missions Manager, GPO), and Richard K. McSheehy (MSC Special Assistant for Apollo Support, Propulsion and Power Division).
Development Task force to carry out the program. This did not end the analysis of the trouble. Reports and recommendations from other NASA centers continued to come to Gilruth until 9 March 1966, one week before the Gemini VIII flight. 12
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