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15 digits is about the precision hand-held calculators provide, right? Many early NASA missions took HP calculators along in missions with trajectory routines

by mchahn 11y ago

15 digits is about the precision hand-held calculators provide, right? Many early NASA missions took HP calculators along in missions with trajectory routines in case the computer failed.

mchahn 11y ago
BTW, the computers in the ship were also made by HP. There is a great story about an incident where a waste recycling problem caused a mission to be aborted. There was urine all over the inside of the capsule. NASA publicly reported that it was a computer failure. Unfortunately HP had just done an ad campaign about their computers in space. HP sued and NASA settled for an unknown amount.
- msl 11y ago
  The flight computers on any manned NASA spacecraft have not been made by HP. The Gemini capsules and the Space Shuttle used IBM computers [1,2] and Apollo used computers made by MIT (primary computers) and TRW (Abort Guidance System) [3]. I could also not find any information on a mission that failed in such a way. [1] http://history.nasa.gov/computers/Ch1-2.html http://history.nasa.gov/computers/Ch1-2.html [2] http://history.nasa.gov/computers/Ch4-3.html http://history.nasa.gov/computers/Ch4-3.html [3] http://history.nasa.gov/computers/Ch2-8.html http://history.nasa.gov/computers/Ch2-8.html
bitwize 11y ago
Handheld calculators typically get between 8 and 12 digits of precision. A four-function calculator will top out at 8; a scientific calculator will offer more (plus scientific notation support). 15 digits is about what's offered in double precision floating point calculations.
- progers7 11y ago
  If you're interested in common handheld calculators, you might enjoy this light-hearted series by Matt Parker titled "Calculator Unboxing": https://www.youtube.com/watch?v=8Nzi1h2m7pE&list=PLt5AfwLFPxWKAINNfxIdYmFVKuk_F_cQq https://www.youtube.com/watch?v=8Nzi1h2m7pE&list=PLt5AfwLFPx...
todd8 11y ago
Hand-held calculators might have been carried on many NASA missions, but not the early ones. The first missions started in 1961 and hand-held HP calculators weren't invented until more than ten years later. By that time we had already been to the moon 6 or 7 times. The first actual hand-held calculator I every saw was a Bowman Brain (simple 4 function calculator) it was for sale in 1971 at the MIT COOP (the bookstore). I only knew one person that bought one; the rest of us continued carrying around our slide rules (they came in handy leather holsters with belt loops.) The HP that came out about a year later was a real scientific calculator. Years before that, sometime between 1965 and 1968, on an episode of Lost in Space (a TV program with a family of early space explorers lost in outer space) the son, Will Robinson, was carrying around a large device about 3 inches thick and a foot tall that looked like a calculator. I thought the idea quite marvelous and went to bed thinking about it and how much better it would be than my slide rule for playing around with calculations. (I was a weird kid.)
- mchahn 11y ago
  We must be about the same age. I went through college with a leather holster for my slide rule. I saw the first TI calculator after graduating from college in '71. I lusted after it and later I went to work at HP and got an HP. I was a super-fan of reverse-polish at that time. HP stayed with RPN for some time.
- skykooler 11y ago
  Did the astronauts use slide rules? I know the E6B is pretty common for pilots still.
  - mchahn 11y ago
    > I know the E6B is pretty common for pilots still. I've used that before. It is not a standard logarithm stick but a vector addition tool. Does one thing very quickly.
    - yuubi 11y ago
      The other side from the vector adder ("front" side at https://upload.wikimedia.org/wikipedia/commons/c/c4/StudentE6BFlightComputer.jpg https://upload.wikimedia.org/wikipedia/commons/c/c4/StudentE... ) includes a circular slide rule with perfectly normal log scales for fuel, time, distance calculations, an extra scale to help with hours/minutes conversions, and some marks for various conversion factors, including lb/gal fuel and lb/gal oil for use in weight/balance. The main difference between a straight and circular rule is that it has only one appearance of the index, so you don't have to move the slide around as much, and it's round so the equivalent of a 10" rule has around 3" diameter. It also has other scales for converting altimeter/airspeed (really pressure gauge) readings into other numbers more useful for certain purposes like true altitude (good for missing obstructions) and "density altitude" (for estimating takeoff performance, also helpful for missing obstructions).

by mchahn 11y ago

15 digits is about the precision hand-held calculators provide, right? Many early NASA missions took HP calculators along in missions with trajectory routines in case the computer failed.

mchahn 11y ago

BTW, the computers in the ship were also made by HP. There is a great story about an incident where a waste recycling problem caused a mission to be aborted. There was urine all over the inside of the capsule. NASA publicly reported that it was a computer failure. Unfortunately HP had just done an ad campaign about their computers in space. HP sued and NASA settled for an unknown amount.

msl 11y ago
The flight computers on any manned NASA spacecraft have not been made by HP. The Gemini capsules and the Space Shuttle used IBM computers [1,2] and Apollo used computers made by MIT (primary computers) and TRW (Abort Guidance System) [3]. I could also not find any information on a mission that failed in such a way. [1] http://history.nasa.gov/computers/Ch1-2.html http://history.nasa.gov/computers/Ch1-2.html [2] http://history.nasa.gov/computers/Ch4-3.html http://history.nasa.gov/computers/Ch4-3.html [3] http://history.nasa.gov/computers/Ch2-8.html http://history.nasa.gov/computers/Ch2-8.html

bitwize 11y ago

Handheld calculators typically get between 8 and 12 digits of precision. A four-function calculator will top out at 8; a scientific calculator will offer more (plus scientific notation support). 15 digits is about what's offered in double precision floating point calculations.

progers7 11y ago
If you're interested in common handheld calculators, you might enjoy this light-hearted series by Matt Parker titled "Calculator Unboxing": https://www.youtube.com/watch?v=8Nzi1h2m7pE&list=PLt5AfwLFPxWKAINNfxIdYmFVKuk_F_cQq https://www.youtube.com/watch?v=8Nzi1h2m7pE&list=PLt5AfwLFPx...

todd8 11y ago

Hand-held calculators might have been carried on many NASA missions, but not the early ones. The first missions started in 1961 and hand-held HP calculators weren't invented until more than ten years later. By that time we had already been to the moon 6 or 7 times. The first actual hand-held calculator I every saw was a Bowman Brain (simple 4 function calculator) it was for sale in 1971 at the MIT COOP (the bookstore). I only knew one person that bought one; the rest of us continued carrying around our slide rules (they came in handy leather holsters with belt loops.) The HP that came out about a year later was a real scientific calculator. Years before that, sometime between 1965 and 1968, on an episode of Lost in Space (a TV program with a family of early space explorers lost in outer space) the son, Will Robinson, was carrying around a large device about 3 inches thick and a foot tall that looked like a calculator. I thought the idea quite marvelous and went to bed thinking about it and how much better it would be than my slide rule for playing around with calculations. (I was a weird kid.)

mchahn 11y ago
We must be about the same age. I went through college with a leather holster for my slide rule. I saw the first TI calculator after graduating from college in '71. I lusted after it and later I went to work at HP and got an HP. I was a super-fan of reverse-polish at that time. HP stayed with RPN for some time.
skykooler 11y ago
Did the astronauts use slide rules? I know the E6B is pretty common for pilots still.
- mchahn 11y ago
  > I know the E6B is pretty common for pilots still. I've used that before. It is not a standard logarithm stick but a vector addition tool. Does one thing very quickly.
  - yuubi 11y ago
    The other side from the vector adder ("front" side at https://upload.wikimedia.org/wikipedia/commons/c/c4/StudentE6BFlightComputer.jpg https://upload.wikimedia.org/wikipedia/commons/c/c4/StudentE... ) includes a circular slide rule with perfectly normal log scales for fuel, time, distance calculations, an extra scale to help with hours/minutes conversions, and some marks for various conversion factors, including lb/gal fuel and lb/gal oil for use in weight/balance. The main difference between a straight and circular rule is that it has only one appearance of the index, so you don't have to move the slide around as much, and it's round so the equivalent of a 10" rule has around 3" diameter. It also has other scales for converting altimeter/airspeed (really pressure gauge) readings into other numbers more useful for certain purposes like true altitude (good for missing obstructions) and "density altitude" (for estimating takeoff performance, also helpful for missing obstructions).