A galactic demon or just human error
Direct link to this page: https://www.hayadan.org.il/flops171099.html
At first it appeared that the mighty Galactic Demon, a mythological space monster with a healthy appetite for research satellites on their way to Mars, had struck again.
On September 23, the US space agency announced that it had lost contact with the "Mars Climate Orbiter," an unmanned spacecraft that was supposed to enter satellite orbit around the planet that day.
The spacecraft fell victim to the same mysterious fate that befell nearly twenty other failed missions to Mars over the years. Of the research satellites launched by the Soviet Union in the 60s and 70s, six failed to even break from their orbit around the Earth towards Mars; Six others suffered various communication failures, crashing on Mars or missing it entirely.
Phobos 2, launched in 1988, failed just before an encounter with one of the moons of Mars, and Mars, launched by Russia in 96 after years of delays, failed to disengage from its orbit around the Earth.
At the same time, the American NASA had its own problems. "Mariner" 3 failed to reach its planned orbit around Mars, "Mariner" 8 crashed into the Atlantic Ocean, and "Mars Observer" failed in 1993. It is easy to understand why the mission planners began to talk, perhaps in jest, perhaps seriously, about galactic demons.
But then, on September 30, it became clear that the loss of the "Mars Climate Orbiter" was not, after all, so mysterious. It turned out to be caused by confusion between the spacecraft's navigation team at the Jet Propulsion Laboratory (JPL) in Pasadena, California, and the team at Lockheed Martin in Denver, which actually operated the research satellite. The JPL team used metric units to quantify the power exerted by the satellite's burners. The Lockheed team, however,
Use yards and miles. As a result, the data transferred between the two groups was misused, the orbit of the research satellite, which was supposed to be precisely adjusted through the measured use of its burners, had a deviation of about 80 km (about 50 miles) when it reached the planet.
This tiny error turned out to be fatal, because the "Mars Climate Orbiter" was supposed to pass above the surface of the planet at an altitude of 140 km. Instead, it passed at an altitude of 60 km and is estimated to have burned up in the Martian atmosphere. Simple human error, then, rather than demonic intervention, was responsible for the loss.
This fact puts the "Mars Climate Orbiter" in a completely different, and more embarrassing, class of space malfunctions. This includes, for example, the case of "Mariner," an unmanned research satellite that was launched to the Moon in July 1. A missing dash in one of its computer programs caused the satellite to deviate from its orbit, and it had to be blown up.
And there is also the story about the experiment carried out on the space shuttle
"Discovery" in 1985, when the figure +10,023 entered into a laser tracking system for the purpose of adjusting the system's sight, was interpreted by the system as a distance in miles instead of feet. And so, instead of being aimed at a point 10,023 feet above sea level, the mirror was aimed at outer space.
In 1988, a series of commands was sent to Phobos 1, a Soviet research satellite to Mars, in which one critical character was accidentally omitted, causing it to lose its stable orbit in space. As a result his solar panels stopped facing the sun; Its batteries, which had stopped charging, were drained, and the satellite was lost.
And in April of this year, an American Centaur rocket intended to be used to launch a satellite into its orbit failed when the number -0.199 instead of -1.99 was mistakenly inserted among its guidance data. As a result, the satellite was placed in the wrong orbit.
Given the danger inherent in human error, it might be better to let the spaceships fly themselves. This is the idea behind "Agent Remote," a software system installed on NASA's "Deep Space" 1 research satellite. However, when the software was tested in May of this year, it turned out to have an unexpected timing bug. So maybe it's not such a bad idea to leave control in human hands after all.
Economist
{Appeared in Haaretz newspaper, 17/10/1999{
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~320296695~~~86&SiteName=hayadan
