NASA Spinoffs in Your Life

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1. #NASADidThatyoutube.com/shorts/lYgULUuiJBU

Word of the day

Satellite (SAT-l-ite). A small body in orbit around a larger body, whether natural, like the Moon, or artificial, like a device launched to orbit Earth or another planet.

• English still uses satellite for an attendant or follower of another person, and for a branch office or off-campus facility that depends on a main campus or office.
• Russian spútnik means both “satellite” and “traveling companion.” English borrowed sputnik in 1957, the year Sputnik 1 became the first artificial satellite.

Bonus word. Aeronautics (from Greek āḗr, “air,” and naûs, “ship”) is the design, construction and operation of aircraft, and the scientific study of flight through the atmosphere. Aeronautics is the A in NASA.

Predict

1. In 1965, NASA paid engineers at Stanford Research Institute to test devices for pointing at words on a computer screen. One was a brand-new device they called the mouse. Experienced users had to lift a hand from the keyboard, reach the device and select a target one letter wide. Make a guess before you read the report. On average, how many seconds did an experienced user need to select a one-letter target with the mouse? Give your reasoning in one sentence.

   Hint. Picture lifting your hand from a keyboard, finding the mouse and clicking on a single letter.

Read the paper

English, Engelbart and Huddart, “Computer-Aided Display Control,” final report to NASA’s Langley Research Center, Stanford Research Institute, 1965. The report is free to read.

Under a NASA contract, Douglas Engelbart’s team at Stanford Research Institute tested five ways to select text on a computer screen, a light pen, a Grafacon, a knee control, a joystick and the mouse. In absolute mode, the cursor’s position followed the joystick’s tilt. In rate mode, the cursor’s speed followed the tilt. When a target appeared, the subject struck the space bar, moved a hand to the device and selected the target, and the computer timed each step and logged each wrong pick. Eight experienced subjects practiced each device for about two minutes before testing. Three inexperienced subjects had never used the system and got no practice period. The table gives the values printed on the bars of Figures 7, 9, 10 and 11 for targets one character wide. The authors also report each device’s time with a 30% penalty for errors. Fixing a wrong pick took about as long as striking the space bar, about 30% of the total time. For each subject, the authors added the subject’s error rate times 30% of the subject’s average time.

1. Experimentation and data, outcome 6 Fill in the last column of the table with average time × (1 + 0.30 × error rate). How close are your penalty times to the report’s? Why would the two differ by a few hundredths of a second?

   Hint. Read the framing again. Did the authors add the penalty to each group’s average or to each subject’s results?

2. Engineering judgment, outcome 6 The mouse ranks first in speed for experienced users and third for inexperienced users. Which device would you recommend for NASA’s text system? How should the group sizes and each group’s practice limit your recommendation?

   Hint. Count the subjects in each group, and compare how much practice each group got before testing.

3. Engineering problem solving, outcome 1 The 30% penalty is the authors’ estimate of what one error costs. Write each device’s time with a penalty p as average time × (1 + p × error rate). For inexperienced users, how large would p need to be for the mouse to beat the light pen?

   Hint. Set the mouse’s expression equal to the light pen’s expression and solve for p.

4. Ethics and impact, outcome 4 NASA’s contract paid for the display-control work in this report. The Advanced Research Projects Agency (ARPA) and the Air Force paid for other parts of the same computer system. Raven’s rap says the mouse is “NASA.” Write one fair sentence about NASA’s part in the computer mouse. Then, why does accurate credit carry so much weight when people argue for science funding?

   Hint. Separate who paid for the work from who did the work.

Exit ticket