By ROBERT E. MCKANN, Chief, Engineering Data and Measurements Office, Mercury Project; Office, NASA Manned Spacecraft Center; WILLIAM A. KELLY, Asst. Chief, Engineering Data and Measurements Office, Mercury Project Office, NASA Manned Spacecraft Center; and WILLIAM R. KELLY, Mercury Project Office, NASA Manned Spacecraft Center




[231] During the progress of the Mercury Project an effective method evolved for the postflight data processing, analysis of systems performance, and timely reporting of the results of the analyses. This method was a compromise between the conflicting requirements of completeness, clarity, and technical accuracy on the one hand and an early publication date on the other. It was learned that there is a need for extensively planning the report preparation effort and establishing procedures for expediting data processing in order to provide engineering data rapidly and in readily usable forms. It was also learned that for a report to be effective, it must be factual, carefully written, and edited.




The success of a complex technical endeavor, such as Project Mercury, depends to a great extent on the ability to analyze and report rapidly the very large amount of information which is generated. Rapid availability of information was essential to maintain the Mercury schedule, since the developments from any mission might need to be implemented for subsequent missions.


Extensive planning and scheduling was done to facilitate the acquisition and preparation of data. The flight data and information were examined to determine weaknesses and malfunctions in the performance of manufactured systems and human organizations, and to verify the proper performance of these systems and organizations. When these analyses had been made, they were summarized and a brief, accurate, and factual report was written so that the management of the program would have available all significant information to aid in making necessary decisions. This primary report of the results for each flight, the Post-launch Memorandum Report, is discussed in detail in this paper.


This paper describes the techniques employed to process raw data into usable form, to obtain the overall analysis of mission results, and to report those results to management.


The processing, of certain data, such as the trajectory information from the radar tracking network, and the numerous reports that were made by the spacecraft contractor and other supporting organizations after each mission, are not discussed in this paper.



Data Sources


The flight data with which this paper is primarily concerned were those data available from the spacecraft onboard tape recorders since these takes contained the most complete data and were available for quick processing. The onboard tape included information pertaining to the operation of the spacecraft systems, the astronauts physiological conditions, the pilot's voice communications, and other special measurements. A list of typical measurements is presented in table 18-I. Most of this information was also transmitted to the ground. and recorded by range network stations, and some of the information was displayed in real time to monitoring personnel. These range-recorded data have often become critical to the analysis conducted after the flight, in addition to serving as a complement for the onboard recorded data. Since the spacecraft sank in deep water following the Mercury-Redstone 4 (MR 4) flight, the onboard-recorded data were not recovered, and the range- recorded data became the only source of [232] information from this flight. In the Mercury-Atlas 9 (MA-9) mission, the tape supply of the onboard recorder was insufficient to provide

Table 13-1.-list of Typical Recorded Flight Measurements


Flight accelerations in three axes
Physiological measurements
Body temperature
Blood pressure
Respiration rate and depth
Events (approximately 20)
Environmental control system
Oxygen supply pressures
Suit pressure and temperature
Cabin pressure and temperature
Static pressure
Heat exchanger temperatures
Oxygen and carbon dioxide partial pressure
Electrical system
Instrumentation reference voltages
Main, standby, and isolated bus voltages and current
Fans and ASCS bus a-c voltages
Inverter temperatures
Communications system
Command receiver signal strength
Command receiver on-off
Reaction control system
Automatic and manual fuel pressures
Fuel line and thruster temperatures
Stabilization and control system
Control stick positions
Spacecraft attitudes (gyros)
Spacecraft attitudes ( horizon scanners )
Automatic system high and low thruster actuation
Spacecraft attitude rates
Onboard time
Time since launch
Time of retrosequence initiation
Time since retrorocket ignition
Structural heating
Heat shield temperatures
Retrorocket temperatures
Shingle temperatures
Balloon drag
Radiation flux density


continuous recording for the entire mission; therefore, the range-recorded data were used to supplement the onboard-recorded data.


The pilot's comments recorded during the mission and in postflight debriefings were an important source of information. This information was used in many cases in defining the performance of the spacecraft or launch vehicle systems when the measured data were lacking or permitted ambiguous interpretations. Even more important, the pilot's debriefings and reports were the only source of information regarding many of his observations.


Additional sources of information during various flights were provided by a variety of cameras which were carried onboard the spacecraft and used to photograph the instrument panel, the astronaut, the view through the spacecraft window, and, for the unmanned Mercury-Redstone and Mercury-Atlas flights, the view field of the periscope.




The analysis of the flight data began at the launch site during the flight and continued until the Postlaunch Memorandum Report (PLMR) was completed. The analysis of problems requiring study beyond the publication date of the PLMR was continued to completion, and the method of reporting the final results is discussed in the following section of this paper.




The results and analyses for each mission were (or will be) presented in five formal NASA reports, which are listed in table 13-II.


The first of these reports, issued in the form of a telegram approximately 2 days after the end of the mission, gave a broad overall summary of mission results as they were known at that time. For most of the flights this report was issued within a day of the end of the mission in order to disseminate the available information as quickly as possible; however, for the MA-9 flight it was found that more time was needed to gather and summarize significant information, and as a result this telegram was issued 3 days after the end of the flight. This first report had a very limited distribution, going only to those organizations directly concerned with the mission.


The second of these reports, also issued in the form of a telegram approximately 6 to 10


233] Table 13-II. Mercury Postflight Reports.

Type of Report

Approximate period to report completion, days a









Telegram (preliminary)








Broad overall summary of mission results as known at that time

Telegram (Interim)








Updated version of preliminary telegram describing status and problem areas.

Postlaunch Memorandum Report (PLMR)








Contains all detailed spacecraft data and description of resolutions of problem areas or status of investigations of unresolved problems. This report contains 95 to 98 percent of all important information that would come from the mission.

Public Release c








Summary report of mission results for distribution to the public.

Technical Memorandum (TM) or Working Paper (WP)

41 d

60 d






Official presentation of detailed analysis of mission. This report is an updated version of PLMR with latest information and in a format suitable for distribution to the technical community.

a Elapsed calendar days from end of mission to completion of final review and editing.
b Interim telegrams were not used for MR-3 and MR-4.
c See references 1 to 5 and this document.
d WP.
e TM, in preparation.

[234] days after the end of the mission for the more recent manned missions, had a dual purpose. The first purpose was to show any significant changes to the information contained in the first telegram, and the second purpose was to describe the status of the analysis of the mission results at that time with emphasis on any problem areas. Any problems encountered during the mission were of particular interest since such problems might have a direct effect on the schedule or the preparations for the next mission; as a consequence, little time was spent in this second telegram discussing systems that had exhibited satisfactory performance. This telegram had the same limited distribution as the first telegram.


The third type of report, the PLMR, was bound into one or more volumes depending on the amount of information contained. This report was completed in a period of 10 to 26 days, and contained 90 to 95 percent of the significant information that would come from the flight. The amount of time needed to complete the report depended primarily on the amount of data collected during the mission. This report was the most important of the postflight reports in terms of its usefulness to the program management in the timely prosecution of the program. This report had a relatively wide distribution within NASA.


The fourth of these reports was a summary of the important highlights of the mission, with classified information deleted to permit release to the public (see refs. 1 to 5).


The fifth of these reports was issued as a working paper (WP) for the Mercury-Redstone manned flights. The WP was used for rapid dissemination of information, and the format and quality of presentation was not suitable for general distribution outside NASA. For the manned Mercury-Atlas flights the fifth report will be issued as a Technical Memorandum (TM), suitable for distribution outside NASA. These TM's (one for each mission) will be distributed within the scientific community after publication. Both the WP's and TM's contained, or will contain, the significant information published in the PLMR's plus any additional results that became available after publication of the PLMR.


The remainder of this paper will be limited to discussion of the preflight and postflight activities related to the PLMR.


Report Planning and Organization Planning


In the early days of the Mercury Project, the planning and organization for postflight analysis and reporting of mission results did not need to be very elaborate, and these plans were made known to the participants on an informal verbal basis. A NASA Project Engineer was responsible for all aspects of a particular flight.


For the first few flights, such as the pad abort flight and early Little Joe flights, the flight time was measured in minutes, with a relatively small amount of data collected. The analysis and reporting effort, though intensive, was correspondingly small in terms of the number of people involved and the total amount of time spent when compared to the later orbital flights. All of this analysis and report preparation was done at the launch site at Wallops Island, Virginia.


The plans for organizing the analysis and reporting efforts continued on an informal basis through the Little Joe phase of the Mercury Project and extended into the Redstone and Atlas phases. As the flight time, amount of data, and number and complexity of the systems to be analyzed increased, and the number of personnel grew, it became difficult and then virtually impossible to disseminate by verbal discussions and telephone calls the work assignments, schedules, changes in plans, et cetera, to the participating personnel. To circumvent these difficulties, informal memorandums came into increasing use. As a result, prior to the MA-5 flight a data processing, analysis, and reporting schedule was prepared for the first time, and w as in the form of a five-page memorandum. This memorandum, which was distributed to all participating personnel and to the necessary organizations, outlined the schedule for data processing and noted when and where various types of data would be available, the assignment of individuals to various sections of the PLMR, and the detailed schedule [235] the writing and editing of the various sections of the report. This procedure was found to be effective, and the memorandum grew steadily in scope and detail as the need for additional information became evident through the subsequent orbital missions. For the MA-9 mission this memorandum had grown to 31 pages. It contained such things as personnel assignments, data-availability and report-preparation schedules, schedule of the pilot's postflight activities including debriefings, locations of various facilities were people would be working on data analysis and report preparation, and a definition of the responsibilities and work scope of the organizational elements participating.




The organization of the effort of the analysis and reporting went through a continuing evolution as the Mercury flight program proceeded, up through the PLMR for the MA-5 flight. By this time, a method of organizing the effort had evolved which was satisfactory in producing in a short time a reasonably complete and factual report, written with sufficient clarity.


As in the case of the dissemination of the plans, the organization of the effort for analysis and reporting was relatively small and informal for the first few flights of the Mercury Project. The effort was headed by the NASA Project Engineer for that particular flight, who largely determined the scope of the analysis effort and edited the various sections of the PLMR.


During a part of the early phase of the Mercury-Atlas and Mercury- Redstone flights, as the analysis and reporting became more complex because of the increasing complexity of the flights, additional NASA organizational elements became more deeply involved in the analysis and reporting. Because of this, there was a movement to create an editorial board consisting of one member from three or four of the major organizational elements involved, with each member having equal responsibility and authority. One of the early Mercury-Atlas reports was prepared under the direction of a three-man editorial board but this arrangement was quickly found to be unworkable mainly from the standpoint of settling policy and procedural questions that inevitably arose during each analysis and reporting effort. The method of managing this analysis and reporting effort reverted for the next flight to an arrangement with a single organization responsible for the effort. This arrangement was kept throughout the remainder of the Mercury Project.


Prior to the first manned Mercury-Redstone (MR-3) flight, the increasing responsibilities for data analysis and reporting had resulted in the assignment of key technical personnel to duties on editorial boards or Senior Editorial Committees headed in each case by the appropriate project engineer. The function of this editorial board was to actively participate in the planning and monitoring of postflight systems testing, data analysis, and editing of sections of the report.


The membership of the editorial board during the early flights changed from flight to flight, but usually one or more members were the same for at least two flights in order to provide continuity and some consistency of effort. The PLMR editorial board for MA-5 and a majority of the systems-performance analysts were for the most part the same people who had served in those capacities for the PLMR for MA-4, and these personnel assignments remained relatively constant for the remainder of the Mercury Project.


As an example of the organizational arrangement of the reporting team, figure 13-1 shows


Figure 13-1. Functional relationships for editorial and support personnel.


[236] the major elements of the task organization for the MA-9 report. The Senior Editorial Committee members and the supporting members were drawn from various elements of the NASA Manned Spacecraft Center, and for the period of the PLMR preparation the members reported functionally to the Chairman of the Senior Editorial Committee. As each member's part of the task was completed, he returned to his parent organization.


The functions of the elements shown in figure 13-1 are described briefly below:


The Manager's office provided the overall directions for the postflight test program. In addition, the Manager's office reviewed the PLMR for technical accuracy, completeness, and policy, immediately prior to printing.


The Senior Editorial Committee comprised the senior editors of the separate parts of the report and the MA-9 backup pilot and these persons directed and coordinated the detailed efforts of postflight testing, analysis, and reporting. The members of this committee also performed a continuous review and editing of the individual sections of the report in an effort to maintain continuity and technical agreement among the sections of the report. The Chairman directed the planning of the overall reporting effort prior to flight, provided intermediate and final editorial reviews of major portions of the report, acted as official representative of the Manager's office, and coordinated the report preparation effort continually through the Senior Editorial Committee.


The Senior Editor of Part I, Mission Analysis, gave overall direction to a team of subeditors and system specialists who performed postflight analyses, and tests required to explain inflight systems malfunctions. These sub-editors participated as required with the system specialists in the analysis of the data from the mission and the preparation of this part of the report which summarized the overall results of the mission.


The Senior Editor of Part II, Data, gathered data-processing requirements prior to flight, planned and provided data processing, presentation, and distribution. In addition, he directed the analysis of data quality and was responsible for the preparation of the flight data section of report.


The Senior Editor of Part III, Mission Transcripts, managed the preparation and editing of the various voice transcripts for both flight communications and post flight debriefings, and planned and conducted the postflight scientific debriefing .


The functional organization shown in figure 13-1 was used in the overall management of the mission analysis and reporting. A more de tailed breakdown of the functional organization of the Part I effort is shown in figure 13-2 to illustrate the depth of organizational detail needed. The personnel for each assignment were drawn from throughout the Manned Spacecraft Center, with assistance from other NASA centers and contractors as needed.


The need for a well-planned organization can best he illustrated by noting that for the MA-9 PLMR analysis and reporting effort, contributions were made by personnel from fourteen NASA organizations, four contractor major organizational elements, numerous organizations of the Department of Defense, the U.S. Weather Bureau, and several colleges and universities. During this analysis and reporting period, approximately 20,000 man-hours were spent by approximately 130 people in producing a 1,000-page 3-volume report in 26 days.


Analysis of Mission Results

Data Processing


To meet the needs for processed data to be used for analysis and reporting purposes in the shortest possible time, several decisions were made as experience was acquired. The maximum use would be made of electronic data processing to provide data in the most readily usable form. Where necessary, manual effort would be used, in addition, to provide the data in a format which would require the least additional manipulation on the part of the analyst. In processing the data the initial format would be made as nearly as possible of a quality that would be suitable for final report use. In this way the data would be prepared for its various types of usage by photographic reproduction rather than by recomputing, resealing, and replotting. The requirements of the analysts would be determined as far as possible well in advance of the generation of the data in order that the parameter arrangements, scale selection, and priority might be determined. As


237] Figure 13-2. Typical functional organization for Part I of report.


successive flights were made, formats were standardized to enable comparison between the data from various flights, thus providing an additional constraint.


When the electronic data-processing method became operational, a decision was made to process all applicable data during one effort for each flight. To permit parallel processing, several copies of the onboard tape were prepared. If the processing results were to be accurate, the tape copying had to be carefully checked. To accomplish this, oscillographic records were prepared from the master and tape copies. These oscillographic records were visually compared. If visual inspection indicated ally differences, the records were compared by superimposing records over a back-lighted glass plate. If there were any significant differences between the records, the tape copy was rejected.


The automatic data-processing capabilities were not easily obtained. Data reduction processes may introduce errors at many points in the system. The accuracies of the basic spacecraft data system were sufficiently high to require more care in the reduction of the data shall was the general practice. Utilization of experiences gained from the preceding flights were required to obtain the product quality and processing efficiency attained on MA-9. The Mercury experiences have indicated that significant improvements in quality and efficiency can still be attained.


The initial effort to use automatic processing methods was begun with the off-the-pad abort and Little Joe tests. In this effort, time-history plots were prepared from telemetered data by using analog plotting methods. The differences between the oscillographic-type records and the analog plots were that the time axis was compressed and engineering units could be rend from the analog plots. The compression of the time axis accentuated the scatter in the data, however, and the processing methods themselves added some additional scatter. As a result, the electronically processed data lacked the desired accuracy. In these cases, the analysts continued to use the oscillographic recordings as a primary source of data.


[238] To improve the quality of the processed data, various techniques of reducing scatter (filtering) were applied and some of the plotted data were smoothed by line fairing. The requirements for the postflight analysis were still not satisfied by the electronically processed data, since vital information might still be lost as a result of data filtering or line fairing. Nevertheless, it was recognized that here was a method which provided all of the flight data in a standard format and in a compact form suitable at least for indicating major trends.


The use of digital computers for the data processing increased as the Mercury Project continued. At first the computer-processed data were used for checking analog plots and later some of the data were plotted from computer-prepared cards by using a small card-fed digital plotter. The data obtained from the digital plotter were hand faired to provide a trace comparable to the analog processed data.


The greatest "bottleneck" encountered in data preparation was in the plotting of data. Initially, one analog plotter was used in preparing the Mercury data. Only one parameter could be plotted at a time and the time to plot was the same as real time. At the time of the MA-5 flight, four analog plotters were in use and they were operated at a speed of eight times real time.


Because of the difficulty in making corrections to the analog plots when graph paper was used, it was decided to plot on a clear plastic film. This innovation speeded the plotting process by making it possible to erase an error rather than replot several parameters on a new page, and by providing a means for superimposing analog plotted data onto digitally plotted data for related parameters. The plastic film was also less affected by temperature and humidity changes than was graph paper.


It was not until the MA-6 mission that digital computers and digital plotters became the primary processing tools. Prior to this mission, the computer was used to prepare tabulations of data in engineering units, and some digital plots were prepared. But now a faster general purpose computer and a magnetic-tape-fed plotter were available. It became the exception rather than the rule to use analog plotters. With these faster tools available, it was practical to sample the data and it was much easier to apply nonlinear calibrations. By this time the electronically processed data had become acceptable, since comparisons of both methods kind shown them to be equally accurate.


Also by this time most of the data requirements had become well established through discussion with systems analysts. These requirements included a definition of the parameters of interest, their grouping for analytical purposes the time periods of concern, the plotting scales, and the priority of processing. Thus by the time of the first manned orbital flight the basic equipment, methods and standards were established. Further improvements were made but these were improvements in methods rather than equipment. The most important of these improvements were:

(1) The plotting density was reduced, thus speeding up the plotting and improving the appearance of the plot. This required more thorough checking to insure against the loss of data during transients. To overcome this fault a variable plotting density was used; that is, each data point was compared with the previous data point. If the difference was more than a predetermined amount, both the previous point and the present point were plotted. If the difference was less than the predetermined amount, a point was plotted at fixed intervals of time.

(2) Instead of rewinding a plotter tape to plot a second parameter on a page, time was saved by plotting the second parameter in reverse.

(3) Special photographic techniques were used to minimize replotting. Analysis plots, normally made with expanded horizontal scales for detailed work, were photographically reduced in the horizontal axis without reduction in the vertical axis. This working plots were compressed in length for use in the reports without it being necessary to replot.

(4) A developmental program was initiated to permit the determination of heart rate by digital means. Such a method became a necessity on the longer flights in order to obtain n complete time history of heart rate. The method developed provided the time between beats so that an average over any selected period of time could be obtained. Statistical treatment of these data was thus made possible.

[239] (5) Much valuable information was voice recorded during flight by the astronaut but its value was to a great extent dependent upon having an accurate knowledge of the time a statement was made. Early methods required that a typed transcript of the voice record be timed with the use of a stopwatch and the voice tape; this method was adequate for the shortduration flights. For the three-orbital manned lights, timing was accomplished by use of the typed transcript and an oscillograph record containing the voice patterns and time from lift-off in 1-second intervals. By simultaneously relating the voice transcript to the voice patterns while listening to the voice tape, an accurate


Figure 13-3. Number of data points and processing time and rate for Mercury flights.


time for each communication was determined. For the longer 6-pass nod 22-pass orbital flights, a method was developed to automate this process to some extent. A magnetic tape recording of the voice, with spacecraft time recorded on a second track, was played while an operator followed the typewritten text. At the first word of each communication in the text, the operator pressed a switch to compute and record the time. This process permitted the rapid preparation of a complete and accurately timed transcript of all of the pilot's voice communications.


Figure 13-3 provides some statistics related to data processing for each flight. As may be noted, the number of data points processed increased rapidly for the longer duration flights; for example, 14 million data points were processed for MA-9. However, the total processing time was held nearly constant at 5 days as the productivity of manpower increased and procedures were improved. Figure 13-4 shows a comparison of the time required for manual processing as compared with semiautomatic and automatic data processing for n given sample of data.


Systems Performance Analysis


Most of the analysis of the Mercury systems' performance was made either at Wallops Island, Virginia, or Cape Canaveral, Florida, by NASA and contractor personnel who were responsible for the spacecraft preflight preparations and checkout and who were familiar with


Figure 13-4. Comparison of data processing techniques.


[240] these systems. The majority of the analysts had extensive experience in appropriate specialty fields.


As discussed in the Data Processing section of this paper, the major portion of the analysis of the early flights in the Mercury Project was made by using oscillograph records and hand-processing only those portions of the records that seemed to be significant. This hand- processing was time-consuming and several days were required to obtain an appreciable amount of data in the form of engineering units plotted against time. The conversion to electronic data processing was a most important factor during the later missions in permitting a rapid assessment of the mission results; without this electronic data processing, an incomplete analysis would have resulted if the same flight schedule had been maintained.


Toward the end of the Mercury Project a few data-comparison plots were prepared by using the electronically processed data. The purpose of such plots was to display time histories of the data for a particular system in a manner to allow very rapid comparison of the nature of the data on previous missions, showing at a glance the normal scatter and variations for both proper and improper system performance. The very limited amount of data prepared in this comparison-plot form was found to be an extremely useful tool for the analysts, the editors, and technical management personnel.


During the analysis and reporting period of the earlier flights, various types of work weeks were tried. The maximum number of hours worked by individuals was limited to 60 except in unusual circumstances. Work days ranging from 8 hours to 12 hours each, in combination with 5-day to 7- day work weeks, were utilized at various times. Experience showed that a schedule of 10 hours a day, 6 days a week, was a good arrangement to accommodate both the schedule and the participants' non-work-connected responsibilities.


In the analysis of the data, it was found that mission-oriented technical personnel were needed to supervise and direct the analysis and ensure that the overall effort would be integrated and fully coordinated. Few of the spacecraft systems could be analyzed as to their performance without considering the performance of other systems and the particular phase


of the mission in question. For example, the temperature of the pilot s pressure suit was directly controlled by the operation of the suit heat exchanger; however, there was an indirect effect resulting from the temperatures in the spacecraft cabin, which in turn were affected by the operation of the cabin heat exchanger, the amount of electrical power being used (heat generation), and whether or not the spacecraft was ill the sunlight or in the earth's shadow Thus an analysis of the suit temperature could not be made without considering possible effects from these secondary sources of thermal disturbance.


Postflight Tests


It was extremely important that immediate action be taken to determine the causes of any system malfunction or failure and the corrective action to be taken, since this information was necessary in order to support subsequent missions.


A person or group was assigned to determine the reason for the malfunction, and these investigations often became quite detailed and time consuming. It was found to lee necessary to require, whenever practice], that the malfunction be repeated with the same or an identical piece of equipment in laboratory tests to demonstrate that the cause of the malfunction was fully understood. In addition, when the flight equipment had been modified to preclude future malfunctions of that type, it was again demonstrated in ground tests with the simulated inflight environment that the modification would do its intended job.


An example of postflight testing that could not be accommodated to the above philosophy of duplication on the ground of inflight malfunction was occasioned by the MA-1 inflight structural failure. It was impossible to duplicate this failure in ground testing, since the inflight loads spectrum resulting from vibration, acceleration, aerodynamic drag, unsteady airflow, and noise could not be simultaneously applied in ground tests. The postflight investigation was therefore centered around tests on the structure of the front end of the launch vehicle, and on the adapter between the spacecraft and the launch vehicle. These tests, and a concurrent analytical investigation, did not conclusively define the exact cause of the failure but did show that strengthening the front end of [241] the launch vehicle and stiffening the adapter would be sufficient to prevent a similar failure. These changes were incorporated in the MA-2 mission, and the flight demonstrated that the modifications were satisfactory.


Report Preparation


The preparation of the PLMR actually began just prior to the mission when some sections of the report that dealt with preflight activities wore written. The main body of the report containing the sections of technical significance was generated during approximately the last 5 to 10 days prior to issuance of the report. During this time, the rough drafts were prepared and examined for accuracy, completeness, and absence of conjecture, by appropriate members of the report editorial staff.


As in the case of data analysis, it was found that mission-oriented technical personnel were indispensable in performing the editing functions. The editors were technically experienced personnel and most had degrees in appropriate specialized fields of study. They were temporarily relieved of their various technical duties in their organizations to serve as editors. There was never any attempt to use non- technical people as editors of technical parts of the PLMR, since the nature of the editing task was such that the use of technical personnel in this function was mandatory .


The experiences in the PLMR reporting indicate that three main factors contributed heavily to the rapid completion of the reporting phase:

(a) All reporting participants were relieved as completely as possible of their day-to-day responsibilities so that they could devote full time to the reporting task. In addition, when possible they were physically relocated to a place away from their usual duty locations in order to minimize distraction by non-reporting duties.

(b) A steady and intensive work week schedule was utilized, consisting of approximately 10 hours per day, 6 days per week.

(c) The editors exercised close and constant supervision of reporting personnel in their tasks of writing the sections of the report, with emphasis on the need for completeness, clarity, accuracy, and absence of conjecture or speculation.


It was quite difficult, of course, to separate key technical personnel completely from day-to-day duties, since these duties needed their continuous attention. However, it had to be done to a large extent, or the postflight analysis for a mission would have proceeded at a relatively slow pace and the program schedule could have suffered. The steady and intensive work schedule of 10 hours per day and 6 days per week, necessary to meet the analysis and reporting schedule, was maintained for two to three weeks on occasion without any apparent ill effects on the work output.


As the reporting of the Mercury mission results progressed from flight to flight it became increasingly clear that a strong editorial policy would have to be followed in order to insure that the PLMR's would be effective. One reason wily this strong editor policy was necessary was that quite often it was necessary to discuss different facets of a subject in different sections of the report, with the sections being prepared by different authors; a strong editorial hand was needed in such cases to make sure that the various discussions were consistent with each other and with the facts. Another reason was that the various sections of the report needed to have a reasonable consistency in the format, and amount of summary material and depth of discussion relating to the systems' performance and their effect on the overall mission results: a strong editorial hand w as again needed to implement and enforce these requirements.


From experience it was thought that a single person should perform the final editing task; however, as the reports became larger and more complex with the longer flights, it also became apparent that one person could not edit all sections of the report in the short time available. The compromise used in the reports of the last few flights was that one person (the Chairman of the Senior Editorial Committee) edited the technically important sections of the report, and the supporting sections of the report were edited by an editorial assistant or one of the members of the Senior Editorial Committee. This arrangement worked quite satisfactorily, although the work load on the Chairman was very great, particularly during the few days just prior to final typing and printing of the PLMR.


[242] During the period just prior to printing the report, the senior editorial committee reviewed and edited all sections of the report. This review was accomplished to insure that the various sections were compatible in the discussions and treatment of common subject matter. The report was then reviewed in detail by the staff of the Project Managers Office for accuracy and technical emphasis. It was found that the various reviews and editings of the sections of the report and the report as a whole were necessary, although publication of the report was delayed somewhat by this process. Experience showed that the most useful report resulted from a compromise between the conflicting requirements of completeness, clarity, and technical accuracy on the one hand and an early publication date on the other. It was also found that a report was ineffective if it was not complete, clear, and factual.




As the Mercury Project progressed from the relatively simple flights to the more lengthy orbital missions, the postflight data processing, mission analysis, and reporting, went through a steady evolutionary process. A number of lessons were learned and are summarized as follows:


Data Processing


(1) Electronic data-processing equipment can accurately process quantities of data that are impossible to accomplish in the same time with manual methods.

(2) Analysis requirements must be determined in advance and data processing must be planned to supply these needs.




(1) Mission-oriented technical supervisors are needed to supervise the analysis in order to insure integration and coordination of the effort.

(2) Extensive time-history data are essential to the analysis of spacecraft system performance.




(1) A report should have all of its technically important sections edited carefully by one person if the report is to be of maximum usefulness.

(2) A report, to be useful, must be a compromise between the conflicting requirements of completeness, clarity, and technical accuracy on the one hand and an early publication date on the other. Such a report is ineffective if it is published quickly but is not complete, clear, and factual.




1. Staffs of NASA, Nat. Inst. Health, and Nat. Acad. Sci.: Proceedings of a Conference on Results of the First U.S. Manned Suborbital Space Flight. Supt. Doc., U.S. Government Printing Office (Washington, D.C.), June 6, 1961.

2. Staff of NASA Manned Spacecraft Center: Results of the Second U.S. Manned Suborbital Space Flight, July 21,1961, Supt. Doc., U.S. Government Printing Office ( Washington, D.C. ).

3. Staff of NASA Manned Spacer raft Center: Results of the First United States Orbital Space Flight, February 20,1962. Supt. Doc., U.S. Government Printing Office (Washington, D.C.).

4. Staff of NASA Manned Spacecraft Center: Results of the Second United States Orbital Space Flight, May 24, 1962. NASA SP-6, Supt. Doc., U.S. Government Printing Office (Washington, D.C.).

5. Staff of NASA Manned Spacecraft Center: Results of the Third United States Manned Orbital Space Flight,

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