Hidden Figures and Human Computers

Posted on Thu, January 26 2017

The breakout movie Hidden Figures tells the story of three African American women who worked as mathematicians at NASA. The story sheds light on the significant contributions of the three women—Katherine Johnson, Dorothy Vaughan, and Mary Jackson—but also the broader impact that women had behind the scenes at NASA.

Johnson, Vaughan, and Jackson all began their careers at the National Advisory Committee for Aeronautics (NACA)—which later became NASA—working as “computers.” Computers were not what we think of them today. They were people, primarily women, who reduced or analyzed data using mechanical calculators—we’ve previously explored the role of computers in astronomy.

The work of computers was largely invisible. Their names never appeared on reports. Still, there’s a lot we can learn about their work through primary sources. In an article for the Annals of the History of Computing, curator Paul Ceruzzi examines an astounding document; a memorandum dated April 27, 1942 that outlines the computing facility at the Langley Memorial Aeronautical Laboratory (LMAL), the main research facility of the NACA and where Johnson, Vaughan, and Jackson worked.

The memorandum, included below, was found in the files of the NASA Langley Research Center in Hampton, Virginia. The memo was written by R. H. Cramer, a representative from the Curtiss Aircraft Company at LMAL, to R. A. Darby, a Curtiss personnel manager. In it, Cramer describes how Curtiss might set up its own computing facility similar to the one he found at Langley.

In the 1930s and 40s Langley researchers primarily concentrated on the analysis of the aerodynamic properties of things like wing sections, propellers, and even whole airplanes. Engineers would begin their work by selecting a trial shape. They then built a scale model and placed that shape in a wind tunnel. In the tunnel, a battery of instruments measured its performance. The data from the test was then reduced and analyzed. Based on the results one parameter of that design was changed by a small increment and tested again. The steps were repeated until the performance was optimum for any given parameter. This method of repeated empirical testing required an enormous amount of computational work.

Engineers originally conducted this computational work, but it tended to lead to bottlenecks in progress. In the memo, the author wrote, “The engineers admit themselves that the girl computers do their work more rapidly and accurately than they would.” In part, this was because the engineers felt their advanced experience was being wasted on “mere repetitive calculations.”

The tone of the memo reveals something of the attitude toward sexual division of labor as it existed in 1942, Ceruzzi noted. Cramer, the author of the memo, had the notion that some jobs were for women and some were not. Ceruzzi wrote, “In every case we know of, the women’s work was subordinate to the work of the men for whom they computed.”

But Ceruzzi also noted that the memo makes clear that the work of a computer required skill and judgment. Computers gathered data by reading pressure values from manometers placed in the wind tunnel. Depending on the application, the data were smoothed, plotted, and interpolated. Data reduction and analysis were carried out with the help of calculators, slide rules, planimeters, drafting tools, and other instruments. The women in these roles knew how to organize computational work and how to do so quickly without making mistakes. This knowledge was unique to them.

  • Black and white photo of human computers sitting at an event.

    Left to Right: Dorothy Vaughan, Lessie Hunter, Vivian Adair (Margaret Ridenhour and Charlotte Craidon in back) Image: NASA

  • Two women stand at larger boards.

    Women working at manometer boards at Glenn Research Center. Boards similar to these were also used at Langley Research Center. Image: NASA, C1949-23011

  • A woman uses an IBM type 704 electronic data processing machine used for making computations for aeronautical research. Image: NASA, #L-1957-00989

  • White and black floor plan.

    West Area Cafeteria (building 1227) from 1944-1948 showing segregated dining. Vaughan served as the head of the West Area Computers. Image: NASA, engineering drawing file #LD-13899

From the memo, we also get an idea of the socioeconomic landscape for women in these positions. While their salaries were low ($1440 and $1620), they were higher than those paid to secretaries and typists. The majority of computers were college graduates, especially those selected as heads of computer groups. While the age of computers at the NACA may have averaged near 21, Cramer noted there were a surprising number of computers nearer to 30. And, the computers did not face discrimination if they were married.

While the memo does reveal some of the roadblocks that Johnson, Vaughan, and Jackson may have faced as women early in their careers, it tells us nothing of the additional discrimination they faced as African Americans. We do know that the NACA was segregated at the time and that the women were called “colored computers.”

Eventually, the introduction of electronic computers, as we know them today, made the profession obsolete. Hidden Figures highlights the uneasiness of the transition from human to electronic computers—Johnson is asked to verify electronic calculations by astronaut John Glenn before his famous Friendship 7 flight. We also see a measure of progress for women in science when we compare this memo to the story of Hidden Figures. In 1942, it was unlikely for a woman to move beyond the role of a computer, but during their careers, Johnson, Vaughan, and Jackson were known as engineers, computer programmers, and mathematicians—often the first in their positions.

What else strikes you about this memo? Is anything surprising to you?

(Note: The following memorandum has been transcribed as it appeared.)

Computing Group Memorandum

Computing Group Organization and Practice at NACA

It has been proposed that a group, or several groups, of professional computers be set up in the Engineering Department at Curtiss in order to increase the accuracy and speed of such work while at the same time reducing the net cost. It is known that the clerical aptitude rating of women is, in general, somewhat higher than the general average for men and particularly, that men who have good engineering aptitude ratings will usually score well below average as to clerical accuracy and speed. The computing work at NACA is done almost entirely by women who are more or less specially trained for such work. The whole situation at NACA with regard to this arrangement is reviewed in some detail. It is generally agreed that the computing set up at NACA is quite satisfactory and economical. It is recommended that an experiment along this line be initiated at Curtiss.,
   This memo was originally prepared as an A.V.O. from Mr. R. H. Cramer, current Curtiss representative at NACA, to Mr. R. A. Darby, dated 4-14-42.

S. H. Hahn

April 24, 1942


To:                      Mr. R. A. Darby
Subject:             Computing Group Organization & Practices at NACA
Reference: (a)   Conference with r. Harrnstein, Mr. Maller, Miss Tucker, Mr. Dearborn, Mr. Valentine, etc.

Purpose of Memo

For possible use in instituting a similar group for general benefit of the Curtiss-Wright Engineering personnel (in particular, Flight Test, Aerodynamics, Wind Tunnel and Structures), we have made some inquiries about the present set-up of the Computing Group, which seem to work very successfully, here at the LMAL of the NACA.

Original NACA Set-up

The idea and organization of the computing section grew most rapidly within the last two years, when the number of computers nearly doubled. Although there are approximately 75 computers now as compared with the 450 engineers (total employees at LMAL at Langley Field is somewhat over 1000) there was at first some opposition to the plan so that it began with only a handful of members. The first organization was conducted as a computing “pool,” much as a typing pool. All the work to be turned out at that time was sent to this central pool, because there was some saving in equipment and the facilities for teaching and delegation of each type of work would be done most efficiently this way.

Now that the idea has won general acclaim, the “pool” has decreased in size, but there are now individual computing groups attached to each section (such as Aerodynamics, Physical Research, . . .), and each section has several groups (consisting of about an average of three computers) attached to each Tunnel or Laboratory. Some tunnels have as many as ten computers while others have one computer who often devotes a part of her time to typing and secretarial duties. That is a rather recent innovation, developing from the desire of the LMAL to formalize their work and reports more than it has in the past. To this end the computers have been urged to attend evening classes in such subjects as mechanical drawing and typing. These classes are open to the public at the local high school. Thus, most of the data and charts now obtained in any of the Sections is organised in a neater and more uniform manner than the former freehand and often penciled and hurried data sheets.

The central pool still does the overflow work from the various sections, or that from small sections or individuals not having a computer permanently assigned to them. The central pool also serves as a training center and personnel supply station, since from the greater variety of its work, a trainee’s ability can better be judged and guided to best advantage there.

Group Organization

Each section has a head computer, but this designation is not very formal, and it is not necessarily an indication of her earning a greater salary, especially among smaller groups. A large section is apt to have an acknowledged head computer, however, who is recognized as such by salary and authority. Her duties, besides including the usual computing work, consist of the delegation of the work items, and the laying out of a program and method of work on each project sent to her section, It is generally felt that the ability of the head computer in the direction of delegating responsibility and getting the most volume of work from her available group is the paramount factor in the efficiency and general working atmosphere of the whole group.


The personal qualifications for these computers are not very rigid. These computers are all women who have obtained their jobs through Civil Service. Some entered merely through the “unassembled” or no-examination-required type of application, the selection being made merely on the basis of stated education and experience. Even in this case the candidates were chosen, it seems, from lists with carious designations, for example—Engineering aid, which merely requires a sort of general intelligence tests. The girls who operate the Comptometers have usually passed a proficiency test on that type of machine, and they are usually not college graduates. There is ample room for their talents, however, because the volume of work often necessitates computers who can perform the routine machine operations with great speed, but who need not have much logical insight into what the result should be or how they should check, etc.

The heads of the groups are college graduates, as are the majority of all the computers. Preference is given to those with major interests in mathematics or science (preferably physics), but of late these restrictions are being lowered so that one college course in mathematics has been accepted as qualifying. A good number of the computers are former school teachers. Their ages may average near 21, but there are a surprising number nearer 30 years old. There is no restriction because of marriage; in fact, some of the computers are wives of the engineers of various classification here at NACA.


What opposition there seemed to have been toward establishing the computer groups was directed mostly toward the expense of the computing equipment. The automatic computing machines and comptometers cost over $500.00 each, while they may not be available today. The automatic calculator is usually the Friden or Marchant, while the comptometer was the Comptometer (Trade Name). The computers were also furnished with 20 inch (log-log duplex) slide rules. Each computing section has one slide rule at least, but in some sections (such as one case where a section contains three girls), each of the computers has one.

The selection of the calculating machine is usually left to the discretion of the computer or computers who are to use it. If the computer has proficiency in the operation of a comptometer (which takes about three months training to attain), she can perform all the same operations available on the automatic calculating machine in practically the same time. The comptometer has the advantage of slightly more rapid adding and subtracting facility. The automatic calculator, however, can be mastered in about two weeks or less. The preference for one machine or the other is thus usually based on the computer’s background in this type of work. The section heads have a decided preference for the automatic calculating machine. They point out the ease of teaching and also more means of checking, and for the type of computer who has some mathematical background the type of work required of her could probably be better done on the calculating machine. The computers required at Curtiss would tend to be of this more versatile type.

Each computing section has one light-table for tracing purposes. These are not very elaborate units in general. A set of five-place logarithmic tables and trigonometric tables is also provided, together with a few scale, triangle and French curves.


The other large expense item is the salaries of the personnel. It is felt that enough greater return is obtained by freeing the engineers from the calculating detail to overcome any increased expenses in computers’ salaries. The engineers admit themselves that the girl computers do the work more rapidly and accurately than they would. This is due in large measure to the feeling among the engineers that their college and industrial experience is being wasted and thwarted by mere repetitive calculations. Mr. Herrnstein himself, for example is glad to admit that, where he used to take a day to work about 1 ½ propeller test runs, now one of this [sic] computers can do 3 runs in a morning.

The salary range is between $1440 and $1620 (which is standard Civil Service sub-professional salary). One or two head girls who have had as much as five years service earn $2000, and the directing head with nearer double this amount of experience is believed to receive $2600. Of course, they will now be paid for 8 hours overtime in addition. The feeling seems to be prevalent, however, that a private industry engaged in more or less temporary war work should be willing to pay slightly higher salaries than would be expected from the more conservative governmental agencies.

The $1440 position carries the title of Junior Computer, while the better salaried position ($1620) would be for an Assistant Computer, and finally a Computer would be the title corresponding to the $1800 bracket. A Head Computer earns $2000 (as does the directing head at present), but there seem to be two unfilled positions called [illegible] ($2300) and Chief ($2600). There is a general agreement no that the new computers with college training begin at $1620, while the $1440 position is reserved for the comptometer operator’s beginning salary.

Type of Work

There is a large amount of simple calculation required in the work here at NACA. Most tunnels have means for taking photographs of banks of nearly a hundred manometers at a time. The computers read off the liquid levels and complete the analysis. On the other hand, some of the calculations are sent to the computers in the form of complicated formulas which necessitate a knowledge of trigonometry and sometimes of mathematics involving the calculus. In general, however, the group head would reduce this more complicated work down to tabular form requiring rather routine operations before it would  be given to the machine operator. Most of the work coming from the engineers is accompanied by a memo of calculating instructions or work-of-mouth explanations. The computers in any one section soon learn what the usual type of calculation required of them would be.

Special data sheets and forms are usually available for the more common calculations.

The consensus of all employees here at the NACA is that the plan is very effective and satisfactory.


R. H. Cramer

CC: Messra, Child, R.E.