Chain of disasters during the exploration of Mars: When NASA confused the metric with the imperial system

The 1990s were a disastrous decade for Mars exploration projects. Of the seven attempts, only two were successful. And behind the apparent ease of Vikings 1 and Vikings 2—a pair of NASA landers and orbiters—hid a more complex reality: Landing on the Red Planet turned out to be much more difficult than it seemed. During the first 50 years of exploration of Mars, almost half of the devices sent there crashed or stopped working.

In September 1992, NASA launched its Martian observer, platform that was to continue and expand the research being carried out Viking orbiters. It was a newly developed apparatus, the first of its class, intended for planetary visits not only to Mars, but also, in the future and with the necessary adaptations, to Venus or even Mercury.

It was built using a standard design typical of conventional communications satellites. This seemed like a good idea from the point of view of using already proven developments, but in the end it was not so. Some of its components that worked well for a few weeks around the Earth will not be able to withstand the rigors of a months-long journey into a much colder environment.

When Mars observer With only a few days left to reach his goal, he was ordered to pressurize the tanks in preparation for braking. What exactly happened is unclear: suspicion points to a small leak of an oxidizing agent (nitrogen tetroxide) from the valve. Although it was a small amount during the 11-month flight, corrosive liquid accumulated in the pipes. Consequently, when the second set of valves opened, it could come into contact with the fuel, causing an explosion. This is just one of several hypotheses, but the sudden failure of communication did not allow a final conclusion to be reached.

Global Mars Explorer (MGS), another study launched four years later, had better luck. After failure observerHowever, the idea of using a spacecraft suitable for all missions has already been abandoned. It was a new design, specially created for work on Mars: the scientific instruments it had were almost identical to those that had been lost in the previous attempt. Relative clauses Earth and Mars the journey was long: 11 months. The journey ended with the craft entering a highly elliptical orbit that would decrease in altitude until it was circular at just 142 miles above Mars. Adaptation took another year and a half, because for the first time solar panels (rather than chemical engines) were used as an air brake. It also had two controllable fins, strong enough to withstand repeated friction from the upper atmosphere.

In the end, Global Surveyor was launched into a sun-synchronous orbit, designed to pass over the same terrain feature at the same solar time. The lighting conditions were the same, and the shadows – always the same – made it easy to detect changes in the landscape.

Although the projected useful life is only two years, MGS received multiple mission extensions (i.e. budgetary allocations), allowing it to remain active for almost 10 years. This was longer than any other spacecraft sent to Mars before. During this time, it received a quarter of a million images, as well as a detailed altimetry image of the planet. This information will be of great help in preparing for future mobile robot operations that are about to conclude.

By November 1996, the Soviet Union ceased to exist. Mars 8 It was to be the first deep-space probe to fly the Russian tricolor flag and was tasked with an ambitious scientific program. In addition to a platform equipped with video cameras and remote sensors, it carried two landing capsules and two penetrators. The latter were six-foot-long darts that would be launched from orbit and plunged into the ground of Mars. Just before impact, they will split into two parts: the nose cone will be buried deep, and the aft part, connected by a series of cables, will remain on the surface. The bow contained a seismometer, thermometers, and mineralogical analyzers, all of which were capable of withstanding drops of up to 186 mph; their measurements will reach the orbiter through a transmitter mounted at the back of the probe.

However, this plan ultimately failed to be implemented. The rocket’s final stage failed and the probe – after a day in the wrong orbit around Earth – disintegrated upon re-entry.

The series of failures continued, this time under the Japanese flag. Nozomi It was a small craft whose instruments were jointly developed by Japan and four foreign space agencies. His goal, like his predecessors, was also to orbit Mars to analyze its topography, atmosphere and neighboring interplanetary medium.

The newest was Nozomi trajectory. To achieve escape velocity without consuming too much fuel, it was forced to pass close to the Moon twice and close to the Earth itself once, further accelerated by the gravitational pull. The maneuver took six months of navigation, but was successful. At the end of December 1998 – with a little help from the engine – he went to Mars.

Unfortunately, another poorly closed valve will waste valuable fuel needed to make the final course correction. Japanese experts were forced to recalculate the trajectory in order to accelerate the deep space probe without wasting fuel. It passed in front of the Earth twice more, but each maneuver meant a new revolution around the Sun. This led to another four years of travel. Odyssey.

The solar flare damaged communications and heater control equipment. The remaining hydrazine in the supply lines froze. Only by carefully controlling the ship’s orientation to take advantage of the sun’s heat could technicians watching the spacecraft from Earth be able to liquefy the hydrazine again.

Finally, in December 2003 – after five and a half years of travel – Nozomi almost reached her destination. Just five more days and he would fire up his maneuvering engine, securing capture. But it was then that telemetry showed that the engine was not responding and was headed for a crash onto Mars. Nozomi was not sterilized before takeoff and therefore could not be allowed to crash due to the risk of possible biological contamination. An order was hastily sent to fire up much weaker attitude control reactors to change its trajectory. Nozomi ultimately passed over Mars at an altitude of 620 miles before becoming lost in space.

Of all the failures of Mars exploration, few are as humiliating as the failure Mars Climate Orbiterlaunched by NASA in December 1998. The meteorological mission was intended to complement the successful Global Mars Explorerwho continued to send excellent quality photographs and measurements. This time the goal was to study the evolution of the atmosphere of Mars over a couple of years. In particular, the abundance and distribution of water vapor, temperature, and suspended dust responsible for the characteristic pink color. Sky of Marswhich the Vikings had already discovered.

During the nine-month journey, the trajectory seemed normal. True, slight deviations were noticed, but this was normal and could be corrected by the shunting engine. In fact, four adjustments were made, so when the probe disappeared behind the planet to carry out the capture operation in automatic mode, almost all the controllers and flight directors were calm.

Almost. But not all.

Climate Orbiter never reappeared or was heard from again. Later trajectory analysis showed that instead of passing Mars at an altitude of 93 miles, it passed less than 60 miles. At this level, the atmosphere was already so dense that air friction was equivalent to the impact of a blowtorch flame on a vehicle. Perhaps it burned out. Perhaps the sudden deceleration destroyed its structure before it even touched the ground. Or maybe the hydrazine in the tank reached the flash point and exploded like a bomb. Or all three events happened at the same time.

Dejection gave way to defeat when the cause of the fatal deviation from the trajectory became known. Lockheed Martin, the vehicle’s manufacturer, provided NASA’s Jet Propulsion Laboratory (JPL) with tracking data in imperial units, which is standard in the aviation industry. But JPL has always worked in metrics. Pounds vs Newtons. And no one approached the issue in time.

General confusion after Climate Orbiter The failure was further aggravated by the fact that there was another similar ship on the way. It was Mars Polar Landerspacecraft belonging to the same Mars exploration program.

NASA’s traditional caution of taking one step before taking the next was replaced by a more aggressive ideology, less concerned with covering all contingencies. The new mantra established by the agency administrator was: “Faster, better, cheaper.” Many believed that the changes were for the worse. Some sardonically added two words to the motto: “pick two.”

The investigation that followed Climate Orbiter The disaster highlighted glaring cases of poor organization, lack of training, difficulties with communication between companies and even ignorance of the functioning of some systems.

Polar lander was designed using much the same criteria: cut costs, limit testing… but its mission was complex. It was supposed to land near the southern polar plain of Mars (about 75° S), collect samples using a robotic arm and subject them to analysis, photograph the area, measure a number of meteorological parameters (pressure, temperature, wind speed), detect ice in suspended condition in the lower layers of the atmosphere and even release a couple of capsules with instruments that will be sent to the frozen ground to study its characteristics.

None of this will happen. Although everything supposedly went well for most of the descent, the car never responded. The most likely explanation is that Polar lander crashed. However, this could not be confirmed because it did not transmit telemetry data during the landing maneuver. Later attempts to photograph it from orbit still revealed a discarded parachute, but no sign of a lander.

Analysis of the malfunction indicated a possible culprit. When the landing gear was deployed at 131 feet, vibration could cause a false signal that the computer interpreted as contact with the ground. This would stop the braking motor, resulting in Polar lander continue your free fall. The impact was too severe for such a fragile vehicle to survive.

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