For all the knowledge of the thousands of scientists and engineers in the space
industry sometimes the old adage of "The best laid plans of mice of men" can be
equally applied to their efforts. This was certainly the case of a Mars climate
orbiter mission of 1999 and this will go down in space history as one of the
biggest facepalms to date. If you're an avid comment reader then you may have
seen comments on my videos about why I tend to use both Imperial and metric
units instead of just metric basically the simple answer is that many people in
the US and the UK still use the Imperial system even though metric is now the de
facto measuring system in the science and engineering worlds. Now this is fine
providing that you don't get them mixed up when you're doing your calculations
like the engineers and navigators of Lockheed Martin and NASA did in 1999. In
the late 1990s NASA was under pressure by the Clinton administration to make
each mission go faster, smaller and cheaper, so rather than focusing on a
single large project NASA diversified their operations
this meant that in 1999 whilst servicing the Hubble Space Telescope and building
the International Space Station, NASA also planned a low-cost program to
operate three missions simultaneously on the Red Planet. The "Mars Surveyor 98"
program featured the Mars Polar Lander with a pair of impact of micro probes on
board and a satellite and communications relay which was the Mars climate orbiter.
this extraterrestrial probe, it was hoped, would conduct the first long-term
detailed study of Martian weather. Mars climate orbiter had to be low mass so it
was fitted with a single solar panel rated at 500 watts at Mars. This
asymmetrical design meant that the spacecraft was subjected to rotational
force as the panel caught the solar wind, the probe could correct for this using
the onboard reaction wheels but these needed to be periodically desaturated or
reset using corrective burns from its hydrazine thrusters. These routine
maneuvers were recorded in a fire on Lockheed-Martin's ground-based
computer from which for navigators had calculated periodic course corrections.
However during the nine month trip regular tiny thruster burns were
compounding into a sizeable problem. As was customary Lockheed Martin's contract
stipulated that all communications should use the standard metric units, so
in daily sensor readings all data was assumed to be the metric standard of
Newton's of force per second unfortunately there had been a major
oversight the files actually contained measurements in pounds of force per
second using the imperial units which was still widely used in the launch
industry at the time. Because one pound force equals 4.45 Newton's force
each of the corrective thruster operations was underestimated
by a factor of 4.45, putting the craft into the wrong
trajectory. These showed up when several navigators at NASA's Jet Propulsion
Laboratory of JPL noticed that something was amiss. The probe was making more than
ten times as many minor adjustments as planned as it tried to compensate to
keep it on course, however these concerns were never raised
formally. On September 23rd 1999 the Mars climate orbiter was scheduled to
approach the Martian surface at a distance of a 140 miles
226 kilometres whilst performing a long retrograde burn to enter an elliptical
orbit around the Red Planet. Just one day before arrival JPL latest calculations
indicated that the probe might be off-course and could approach Mars at an
altitude of just 93 miles or 150 kilometers. The operations team met and
discussed the possibility of executing a contingency burn to raise the trajectory
of a probe but with only a day to upload and carry out this maneuver and some
uncertainty about the precise location of a probe the burn was never executed.
Now the team could only hope that the approach would not be further off course
then calculated. If the probes altitude dipped below 53
miles or 80 kilometres it would burn up in the atmosphere. Far from Earth, Mars
climate orbiter continued its course and at 9 a.m. UTC began its main engine burn
the probe decelerated and passed beyond the horizon of Mars out of radio contact.
23 minutes later the ground control team listened for a signal but heard only
silence. The Mars climate orbiter was never heard from or seen again and no
wreckage has been found to date but more detailed calculations later indicated
that its course fell to just 37 miles or 60 kilometers from the surface, at this
altitude there was no way back the atmospheric friction was far beyond the
fragile probes limits and the orbiter was destroyed. After the incident a
report was commissioned which is still available to download and read which
criticized the lack of communications within NASA and with a contractor
Lockheed Martin and the lack of training for key operatives on the mission.
Lockheed Martin and JPL learned from their mistakes five years later the two
organizations together developed the Mars Reconnaissance Orbiter a mission
that accomplished many of the goals of its ill-fated predecessor using
exclusively the international language of scientific measurement namely the
metric system. Now technically the probe was not lost because of maths but
because the calculations were fed the wrong information, namely good
old-fashioned human error. It's the old programmer saying of rubbish in rubbish
out but when all the data is correct it's amazing what can be done with just
the power of math. Our modern world and things like space probes to Mars would
just not be possible without someone doing the calculations. If you've ever
wondered what it takes to calculate the route for a Martian probe other guys
over at brilliant.org can help you. Brilliant is an interactive
problem-solving website where you get to learn by solving real-world problems and
think like a scientist or astronomist. There are tons of problem-solving
courses on things like gravitational physics that underpinned a motion of the
planets or you can try your hand at astronomy and do things like finding out
the size of the universe and if you're into rockets and stuff you can try
classical mechanics to work out how things move around on earth and in space.
Sounds like rocket science? well it is but that doesn't mean the say has to be
hard. Brilliant do this by showing you
problems and breaking them down into easy-to-understand steps then putting
them back together so you can see how the overall process works they also have
a large active worldwide community ready and willing to help you along every step
of a way so you're never alone. To help support as a curious droid and to learn
more about brilliant just click on the link to brilliant.org/curiousdroid
and sign up for free. As a special bonus for curious droid viewers,
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