The Mars Climate Orbiter
In late 1998, NASA launched the Mars Climate Orbiter. After traveling through space for nearly 300 days the spacecraft was supposed to enter Mars’ orbit at an altitude of 226 km. Entering at this altitude should have given the Orbiter plenty of margin for error as the minimum altitude the spacecraft needed was just 80 km. Upon entering the atmosphere NASA lost communication with the orbiter forever.
It appears that the orbiter had entered orbit 23 km below the minimum altitude, that is 57 km, and promptly burned up. How could NASA have miscalculated? The problem was down to communication between software.
A NASA review board found that the problem was in the software controlling the orbiter's thrusters. The software calculated the force the thrusters needed to exert in pounds of force. A separate piece of software took in the data assuming it was in the metric unit: newtons.
Had there been clearer internal communication between the software, and the 2 teams involved in writing the software, the mission may have been a success and not a wasted hundreds of millions of dollars.
The Atomic Bomb
The atomic bombs that fell on Japan in 1945 represent the first and only time in history that nuclear weapons had ever been used in war. The importance of this event cannot be overstated, especially since it might have been avoided if not for a simple misunderstanding.
The misunderstanding arose when the Japanese ruler was asked if Japan would surrender during World War II, the Japanese ruler used the word “mokusatsu” in response. Now, what the Japanese word meant was “we withhold comment – pending discussion”, but when the response was sent to Washington the word was mistranslated to mean “We are treating your message with contempt”.
This was picked up by the media and spread like a wildfire around the world. Undoubtedly frustrated by what he thought the response meant, and knowing he needed to respond sternly, President Truman decided that the atomic bombs were the perfect weapon to use. Why this message wasn’t more heavily scrutinised for any possible mistranslation seems very strange, but regardless, this simple mistake contributed to 150,000-250,000 people being either killed, injured, or exposed to radiation.
Tenerife Air Disaster
A terrorist incident at nearby Gran Canaria Airport on March 7th 1977 lead to the Tenerife airport handling many more planes than usual. Because of the extra number of planes, the taxiway became blocked and the airport over congested forcing many of the planes to taxi on to the runway as flights resumed later that afternoon. Add to this the dense fog and it was a disaster waiting to happen.
Due to the fog KLM flight 4805 missed their correct taxi lane and ended up in the same lane as Pan Am flight 1746. The KLM captain then mistook the air traffic controllers’ orders and initiated a take-off at the exact time the Pan Am flight began to taxi forward. The Air Traffic Control towers bungled the communication with KLM flight 4805, and the captain continued forward at take-off speed. Out of the fog just 300 feet away the Pan Am plane would appeared.
The Pan Am's captain tried to steer off into the grass but the KLM flight was travelling too fast and the 2 Boeing 747 planes collided. The KLM plane exploded and everyone aboard was killed instantly but thanks to the Pan Am pilot steering towards the grass 61 people managed to survive the devastation. In total 580 people lost their lives in deadliest accident in aviation history.
The Proton Rocket And Its Inverted Accelerometer
The Proton rocket programme was a Soviet rocket programme named in reference to previous Soviet space missions. One particular proton rocket went off course, lost control and eventually crashed back to earth.
The Soviet investigation team discovered that the accelerometers in the rocket had been put in upside down. These accelerometers had initially required technicians to go in and install them. So how did they manage to make such a mistake?
The accelerometers had arrows on them to show which orientation they were supposed to be in but the mounting plates that they were to be mounted to didn't. They did have mounting pins to make it hard to install these accelerometers in anything but the correct rotation but apparently with enough brute force you could still mount them upside down. The rocket was getting its signals backwards and was unable to control itself correctly and so ended up crashing. The cost was estimated to be $1.3bn.
Air Florida Flight 90
On January 13, 1982, Air Florida Flight 90 was due to travel from Virginia to Hollywood International Airport in Fort Lauderdale, FL, with a layover in Tampa.
Conditions were snowy, and the aircraft had not been de-iced correctly and neither did it have its engine anti-icing system activated. This caused instruments and sensors to freeze and so fail to register the correct readings. While the pilot thought that they had throttled up sufficiently for take-off, in actual fact they didn’t have enough power.
The Boeing 737’s run-up took almost half a mile (800m) longer than it should have done. As they set off down the runway, the first officer noticed that something was wrong with the plane’s instruments and that it wasn’t capable of getting airborne. However, his attempts to communicate this were brushed off by the captain, who ordered the take-off to continue.
The plane crashed into the 14th Street Bridge. Later, reports showed that there was sufficient space for the aircraft’s take-off to have been aborted – if only the flight crew had been communicating better. 78 people were now dead.