How many times have you smacked your forehead in disgust at making a “silly mistake” on a math test? Maybe you added wrong. Maybe you forgot your units. You probably feel a little stupid for not following the directions to “Check Your Work!” At least it was only one little test. You’ll be sure to do it when it really matters.

Most people wouldn't guess that rocket scientists sometimes fail to catch silly mistakes, especially because it matters. But they do, and have lost machines that cost more than your average Hollywood blockbuster.

Did you know? 2007 was the 50th anniversary of spaceflight. Sputnik 1 was launched on October 4, 1957 by the former Soviet Union. The USA launched Explorer 1 in 1958 (after several attempts exploded).

One such mistake happened in November 2006. The Mars Global Surveyor (MGS) had been photographically mapping Mars since 1999. A computer error in September 2005 caused a problem with the MGS radio antenna. Not to worry, because in June 2006, a program was uploaded to fix the problem. What they didn't know was that a single command was put into the wrong part of the computer memory.

On November 2, 2006, this one command allowed the solar panels to rotate too far. The Sun began to heat one of the batteries, causing the computer to stop charging its other batteries. In a few days, the spacecraft ran out of power. Since NASA can’t fix this problem from Earth, the MGS is now space junk.

Perhaps NASA’s silliest mistake was back in September 1999. The Mars Climate Orbiter (MCO) was to observe Martian weather systems and relay communications. The spacecraft was to fire its engines to enter orbit at an altitude of 145 km. Instead, the spacecraft entered the atmosphere at 57 km, and the friction caused it to burn up.

This was no computer failure, but rather a human using the wrong units. NASA uses metric, but USA-based engineers often use imperial. To put the MCO in the proper orbit, a calculation for its momentum (mass x speed) was needed.

Instead of the expected metric Newton-seconds, an engineer used imperial pound-seconds. His answer was 4.45 times bigger than it should have been. The MCO cost over $100 million.

It would seem that NASA has bad luck when it comes to Mars, but the Moon too, has been the site of mistakes. Did you know? In December 1999, the Mars Polar Lander crashed on Mars. It is believed that a vibration from the lander’s legs extending caused its computer to shut off the engines too early.

In 1969, the Eagle lander started spotting landmarks two seconds faster than it should have during its descent. When the computer realized this, it overloaded with information. It seemed there were two possible outcomes: abort the landing or crash. Fortunately, other computers took over and the Eagle made a successful landing.

Two of these other computers were Neil Armstrong and Edwin “Buzz” Aldrin. The machine error occurred on July 20, 1969, a few hours before these two men walked on the surface of the Moon. Luckily, Armstrong’s training as a pilot and Aldrin’s expertise in orbital mathematics saved the mission (Apollo 11) and their lives.

Astronauts’ training has more to do with responding to mistakes than avoiding them. The MGS and MCO disasters would probably not have occurred if astronauts had been there.

Did you know? The word disaster comes from the Latin/Greek dis + aster meaning “bad star.” Ancient Greeks and Romans thought such events were caused by stars or planets being in an unfavourable part of the sky.

So check your work, and learn from your mistakes. The biggest leaps forward, be they in a math problem or across an alien landscape, start with the smallest steps.

Learn More!

Chaikin, A. (1994). A Man on the Moon: The Voyages of the Apollo Astronauts. Penguin, Toronto.

Sagan, C. (1980). Cosmos. Random House, Toronto.

Sagan, C. (1994). Pale Blue Dot: A Vision of the Human Future in Space. Random House, Toronto.

Barnhart, R.K., ed. (1988/2004). Dictionary of Etymology. Chambers, New York.

Check out the fantastic images of ongoing and upcoming NASA missions here

Books and movies that directly concern some of the content in this article:

From the Earth to the Moon (1998), 12-part HBO miniseries based on Chaikin's book.

The Right Stuff, by Tom Wolfe, 1979. Film version released by Warner Brothers in 1983, directed by Philip Kaufman, stars Ed Harris, Scott Glenn, Dennis Quaid, Sam Shepard, and Barbara Hershey. Harry Shearer (The Simpsons) and Jeff Goldblum (Jurassic Park) have small roles.

Apollo13, originally titled Lost Moon (1994), by James Lovell and Jeffrey Kluger. Film version released by Universal in 1995, directed by Ron Howard, stars Tom Hanks, Kevin Bacon, Gary Sinise (CSI: NY), and Kathleen Quinlan. James Lovell (portrayed by Hanks) has a cameo in the last scene.

Darcy J. Gentleman is a Toronto-based science writer. In a previous life as an astronomy student, he remembers needing lots of coffee to calculate the switch from Gregorian to Julian. Fortunately, he now knows how to use the magical internet( to figure out that 02:29:08 on February 29, 2008 is 2454525.6035648147 in Julian time.


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