Among NASA's amazing successes, some missions have not gone off as planned
Monday, August 4, 2014, 5:47 PM - In honour of the technical difficulty* that caused a delay in Day 5 of 'Mars Week', here's some of the missions to Mars that have suffered failures over the years.
If you look at the record of successes and failures for the all missions that have been destined for Mars, there's somewhere around a two-thirds failure rate so far. However, when only looking at NASA's record, out of the 20 missions they've launched, only five have been labeled as failures - that's a 75 per cent success rate for the agency's scientists and engineers! Still, with how complicated it is to build these satellites and rovers, launch them, fly them to Mars and either insert them into a proper orbit or actually land them on the surface in one piece, it's work a look back to those five failures, to see what went wrong
Failure to launch
Some missions never made it out of Earth's orbit, especially in the early days. Mariners 4, 6, and 7 all made successful flybys of Mars, and Mariner 9 became the first Mars orbiter, but Mariners 3 and 8 weren't quite so lucky. Mariner 3 actually reached space, but it failed to properly separate from the rocket that got it there, and it is now a piece of space junk floating around in Earth's orbit. Mariner 8 didn't even make it that far. Just after launch, the rocket carrying it suffered a failure. Flying off course, the rocket and spacecraft were lost when they ended up crashing into the Atlantic Ocean.
Lost in Space
The Viking missions from the mid-70s were an incredible success for NASA, but it was over 15 years before another mission was launched after them. Mars Observer left Earth in 1992, set for an August 1993 arrival, but just three days before it was set to achieve orbit, it suffered a critical failure that caused NASA to lose contact. Exactly what happened is still unknown, but the most likely explanation is that an engine failure sent the spacecraft into a spin from which it couldn't recover. We aren't even sure if the spacecraft actually went into Mars orbit or if it's just been circling around the Sun since.
Lost in Translation
Mars Global Surveyor and Mars Pathfinder, both launched in the mid-90s, went off without any problems, but the late-90s weren't so good for NASA. In probably the most well-known 'blunder' for the agency, the Mars Climate Orbiter, launched in 1998 to orbit the planet and examine its climate, instead burned up in Mars' thin atmosphere. The reason for this? The software that calculated the spacecraft's orbital insertion used Imperial units (pound-seconds), but the system that actually used those results expected the units to be metric (newton-seconds). With no conversion taking place in between, it caused the spacecraft's engine burns to be mistimed, which made it miss its orbit and dive into the Martian atmosphere.
Launched less than a month after the Climate Orbiter, the Mars Polar Lander arrived at Mars in early December 1999. It was on course for entering the atmosphere, for a thruster descent to the surface, when it entered a planned communications blackout, and was never heard from again. Ultimately, it was determined that a sensor in the landing legs, which tells the landing thrusters to cut out, tripped early. According to the investigation: "At 40 meters altitude, the lander has a velocity of approximately 13 meters per second, which, in the absence of thrust, is accelerated by Mars gravity to a surface impact velocity of approximately 22 meters per second (the nominal touchdown velocity is 2.4 meters per second). At this impact velocity, the lander could not have survived."
The track record for NASA after the turn of the century has been exemplary, with success after success. However, there's one honourable mention for this list. Opportunity's MER sister, Spirit, is considered a success on the record, since it made the journey, landed and went on to extend its original 3-month mission on Mars to over 6 years long. Unfortunately, while navigating around a large rock nicknamed 'Home Plate' in May of 2009, the rover became stuck in soft soil. Months of testing with her duplicate back here on Earth failed to work out a solution to Spirit's problem, and in March 2010, she ceased communication. Given that Opportunity continues to run strong these days, it's safe to say that Spirit would probably be faring just as well had it not become stuck. When it comes down to it, Spirit was most certainly a success, but it was just a misfortune of terrain and timing that forced the mission to end.
*Three-quarters of the way through writing Friday's entry, an attempt at downloading an image from the NASA Jet Propulsion Laboratory website cause my browser to crash. This cost me everything I'd written, and forced me to start over again. It just goes to show you, you never can tell when something is going to go wrong.