Pilot Virgil I. Grissom’s post-flight Mercury-Redstone (MR-4) report

(References to the accompanying slide presentation deleted)

INTRODUCTION

The second Mercury manned flight was made on July 21, 1961. The flight plan pro­vided a ballistic trajectory having a maximum altitude of 103 nautical miles, a range of 263 nautical miles, and a five-minute period of weightlessness.

The following is a chronological report on the pilot’s activities prior to, during, and after the flight.

PRE-FLIGHT

The pre-flight period is composed of two distinct areas. The first is the training that has been in progress for the past 2.5 years and which is still in progress. The second area, and the one that assumes the most importance as launch day approaches, is the participation in the day-to-day engineering and testing that applies directly to the spacecraft that is to be flown.

Over the past two years, a great deal of information has been published about the astro­naut training program and the program has been previously described in Reference 1. In the present paper, I intend to comment on only three trainers which I feel have been of the greatest value in preparing me for this flight.

The first trainer that has proven most valuable is the Mercury procedures trainer which is a fixed-base computer-operated flight simulator. There are two of these trainers, one at the NASA-Langley Air Force Base, Virginia, and one at the Mercury Control Center, Cape Canaveral, Florida. These procedures trainers have been used continuously throughout the program to learn the system operations, to learn emergency operating techniques during system malfunctions, to learn control techniques, and to develop operational procedures between pilot and ground personnel.

During the period preceding the launch, the trainers were used to finalize the flight plan and to gain a high degree of proficiency in flying the mission profile. First, the systems to be checked specifically by the pilot were determined. These were to be the manual propor­tional control system; the rate command control system; attitude control with instruments as a reference; attitude control with the Earth-sky horizon as a reference; the UHF, HF, and emergency voice communications systems; and the manual retro-fire override. The proce­dures trainer was then used to establish an orderly sequence of accomplishing these tasks. The pilot functions were tried and modified a great number of times before a satisfactory sequence was determined. After the flight plan was established, it was practiced until each phase and time was memorized. During this phase of training, there was a tendency to add more tasks to the mission flight plan as proficiency was gained. Even though the MR-4 flight plan contained less pilot functions than the MR-3 flight plan, I found that the view out the window, which cannot be simulated, distracted me from the less important tasks and often caused me to fall behind the planned program. The only time this distraction concerned me was prior to retro-fire; at other times, I felt that looking out the window was of greater importance than some of the planned menial tasks. In spite of this pleasant dis­traction, all tasks were accomplished with the exception of visual control of retro-fire.

The second trainer that was of great value and one that I wish had been more readily available prior to launch was the air-lubricated free-attitude (ALFA) trainer at the NASA – Langley Air Force Base, Virginia. This trainer provided the only training in visual control of the spacecraft. I had intended to use the Earth-sky horizon as my primary means of attitude control and had spent a number of hours on the ALFA trainer practicing retro-fire using the horizon as a reference. Because of the rush of events at Cape Canaveral during the two weeks prior to launch, I was unable to use this trainer. I felt this probably had some bearing on my instinctive switch to instruments for retro-fire during the flight, instead of using the horizon as a reference.

The third training device that was of great value was the Johnsville human centrifuge. With this device, we learned to control the spacecraft during the accelerations imposed by launch and reentry and learned muscle control to aid blood circulation and respiration in the acceleration environment. The acceleration buildup during the flight was considerably smoother than that experienced on the centrifuge and probably for this reason and for obvious psychological reasons, the g-forces were much easier to withstand during the flight than during the training missions.

One other phenomenon that was experienced on the centrifuge proved to be of great value during the flight. Quite often, as the centrifuge changed rapidly from a g-level, a false tumbling sensation was encountered. This became a common and expected sensation and when the same thing occurred at launch vehicle cutoff, it was in no way disturbing. A quick glance at my instruments convinced me that I, indeed, was not tumbling.

The pilot’s confidence comes from all the foregoing training methods and many other areas, but the real confidence comes from participation in the day-to-day engineering deci­sions and testing that occur during the pre-flight check-out at Cape Canaveral. It was dur­ing this time that I learned the particular idiosyncrasies of the spacecraft I was to fly. A great deal of time had already been spent in learning both normal and emergency system operations. But during the testing at the pre-flight complex and at the launching pad, I learned all the differences between this spacecraft and the simulator that had been used for training. I learned the various noises and vibrations that are connected with the operation of the systems. This was the time that I really began to feel at home in this cockpit. This training was very beneficial on launch day because I felt that I knew this spacecraft and what it would do, and having spent so much time in the cockpit I felt it was normal to be there.

As a group, we astronauts feel that after the spacecraft arrives at the Cape, our time is best spent in participating in spacecraft activities. This causes some conflict in training, since predicting the time test runs of the pre-flight checkouts will start or end is a mystic art that is understood by few and is unreliable at its best. Quite frequently this causes train­ing sessions to be cancelled or delayed, but it should be of no great concern since most of the training has been accomplished prior to this time. The use of the trainers during this period is primarily to keep performance at a peak and the time required will vary from pilot to pilot.

At the time the spacecraft is moved from the pre-flight complex to the launching pad, practically all training stops. From this time on, I was at the pad full time participating in or observing every test that was made on the spacecraft – launch-vehicle combination. Here, I became familiar with the launch procedure and grew to know and respect the launch crew. I gained confidence in their professional approach to and execution of the pre-launch tests.