Excerpt from HP Key notes, March-May 1982 Vol. 6 No. 2:
HP-41’s Again Aboard Columbia
Unless you have been hiding in an igloo near the North Pole for the last year or so, you know all about the space shuttle Columbia, which we featured on the cover of V5N1. And, because you read every KEY NOTES, you know that astronauts use our HP-41 handheld computers onboard Columbia for various flight-related, radio-contact, and backup operations. And, no, their programs are not in the Users’ Library nor are they for sale. They contain NASA proprietary information and are for use only on the space shuttle.
For the last Columbia flight, near the end of last March, the two HP-41 computers were purchased over-the-counter by NASA from a Houston, Texas, office-equipment store, and were tested rigorously before being approved for flight. They are identical to the hundreds of thousands of HP-41’s sold since 1979.
One HP-41 computer, dedicated to what NASA calls the acquisition-of-signal program, was the only convenient means the shuttle crew had to estimate the time, location, and radio frequency of their next contact with Earth. Also, if the astronauts are awakened at night by an alarm, they can tell at a glance how long it will be before they can discuss the problem with Mission Control.
The second HP-41 computer acts as an electronic secretary for the astronauts – reminding them of daily chores with alarms and flashing messages. Each morning, the astronauts programmed their computer with five to ten alarms. That way they didn’t have to write down on paper all their scheduled activities. In other words, the HP-41 helped them to keep on top of all of their daily “housekeeping” activities.
In addition to helping the crew organize its time, the second HP-41 computer was kept ready for flight-critical, deorbit-burn calculations. Once during each orbit around the Earth, the shuttle has an opportunity to land at one of six contingency locations. During a routine flight, Mission Control supplies the shuttle crew with deorbit-burn information. Should the shuttle encounter an emergency, however, the astronauts would rely on the HP-41 for these calculations.
Two other programs – one to help balance the Columbia prior to re-rentry, and another to pin-point Earth observation sites – also are available to the crew and would be run on the HP-41’s.
The HP-41’s do not take the place of the shuttle’s larger, general-purpose computers. However, they do complement the shuttle’s larger systems and provide the crew with personal-computer convenience. Also, new and different HP-41 programs can be written between flights – quickly enough to keep up with with many of the astronauts’ changing computational needs.
We are very proud of the HP-41, and we are happy that NASA chose this handheld marvel for use on the space shuttle. Already the new Time Module is an asset to this mission and, in the future, the new HP-IL Module and the various HP-IL peripherals will surely prove their usefulness. We’ll keep you informed as NASA makes more use of the HP-41 system.
Astronaut Gordon Fullerton aboard Columbia on the last flight, using his HP-41. Notice that he is "sitting" in midair, in the "zero" gravity of outer space. (Photo courtesy of NASA.)