With the surprise landing of a Chinese
Rover Yutu 2 or the Jade rabbit 2 and the Chang'e lander on the far
side of a moon on the 3rd of January 2019, I thought it'd be interesting to
see what sort of things we've actually put up on the moon and to speculate on
what might happen to them in the future. Now it will come as no surprise that the
Apollo missions have left behind the most amount of items but long before
they were even thought of the Soviets pulled off something that not for the
first time the U.S. thought they couldn't actually do. In 1959 the Soviet
Luna 2 probe was the first man-made object to intentionally impact on to the
lunar surface, the closest to the US had got to the moon by then was with a
pioneer for but that was 60,000 kilometers away which was a bit of a
shock because the U.S. believed that while the Soviets had bigger rockets
they were lacking the precision in their navigation and guidance systems.
Although these early probes were designed to crash into the moon, in a
piece of pure propaganda Luna 2 left behind a calling card to remind everyone
else that they were here first. Luna 2 was loaded not only with experiments but two small spheres one 7.5 cm and the other 12 cm across and made from pentagonal pennants each stamped with the insignia of the Soviet Union and the date 1959 on the larger of the two. These
spheres had an explosive core and were designed to explode and scatter the
pennants on impact. Although these were the very first man-made items to make it
to the moon their fate is unknown as Luna 2 impacted a speed of around 3.3 km/s
about 12,000 kilometers an hour and was probably vaporized on impact. A
third sphere was in the Luna twos rocket body which crashed about 30 minutes
later that was filled with liquid and aluminum strips with the year 1959 and
Union of Soviet Socialist Republics engraved upon them. As the space race
intensified the lunar research also increased the U.S. sent the Ranger
probes to take close-up images of a moon they did this like the soviet lunar probes
by crashing into the moon whilst transmitting live TV signals back to
earth. At one point it was called the "shoot and hope" program because the first
six out of nine range probes either failed on the launch pad, missed the moon
completely or failed before reaching the moon's surface. This was followed up by
the surveyor program to find out more about the actual surface and potential
landing sites for Apollo as it was feared by some but any Lander would just
sink and disappear into the lunar dust five out of the seven surveyors
successfully landed and proved that theory was groundless. Also around his
time the lunar orbiter program was the first NASA craft orbit and survey the
moon including mapping its gravitational field again for the Apollo missions. After
their missions were complete the orbiters were deorbited and crashed into
the moon so they wouldn't pose any threat to the Apollo missions. With the lunar orbiters one, two and three ending up on the far side of the moon. The Soviets had
a similar hit and miss success rate with the first four attempts of a soft landing
failed. Finally on the 3rd Feb 1966 lunar 9 became the first lunar lander to
achieve and survive a soft landing. Something which is often overlooked is
it the rockets that carried the spacecraft also ended up on the moon. The
third stage of the Saturn V that carried the Apollo missions 11, 13, 14, 15,
16 and 17 also crashed into the moon and some of their positions are well known.
Apollo 12 third stage was planned to go into a solar orbit but due to venting of
his fuel tanks it didn't have enough propellant and ended up in a stable
orbit between the earth and the moon. Even though Apollo 13 never landed its
spent third stage was detected hitting the surface and the impact crater has
been captured by the Lunar Reconnaissance Orbiter camera some 135
kilometers away from the Apollo 12 site. Apollo 12 and all the following missions
left behind the ALSEP or Apollo Lunar Surface Experiments Package. This
included a range of experiments like the seismometer which picked up the Apollo
13 third-stage impact as well as other devices through the
analysis of micro meteorites, the moon's gravity, magnetic field, solar radiation,
atmosphere and internal structure. Apollo 11 left behind the lunar laser ranging
experiment which is the only lunar experiment still to be working today and
uses an earth-based laser to measure the distance from the earth to the moon with
an accuracy of about three centimeters. The Apollo missions landed with a
complete lander but they couldn't return in the same way, only the ascent stage of
the lander took off to return the crew and they had a very strict weight limits
too much weight and they might not make it back to the command module literally
every kilogram made a difference and that was a reason for leaving behind the
seemingly random list of objects as we will see later. Once the crews had
transferred from the ascent module to the command module, the ascent modules were released to crash back onto the lunar surface except to Apollo 13 which was
used as a lifeboat to get the crew back to earth and burned up in the Earth's
atmosphere and Apollo 10. Apollo 10 was a complete dress rehearsal for Apollo 11
except for the landing. Gene Cernan and Thomas Stafford took the lunar lander to
within 15 kilometers of the surface before returning. In fact the ascent
stage was deliberately short fueled to stop the crew from attempting a landing
on the moon because if they did they wouldn't have enough fuel to make it
back to the command module. The Apollo 10 descent stage was left in orbit but fell
back to the moon and it's position is unknown. After the crew had transferred
the ascent stage nicknamed "Snoopy" fired its engine until it ran out of fuel this
sent it out into an orbit around the Sun and it's still there,
somewhere, in an orbit slightly shorter than that of the Earth, the only manned spacecraft
left in space without a crew. If you look at the inventory of items left behind
for each mission you'll see a lot of really rather mundane items.
Things like filters, urine and defecation bags, food bags, chair arm rests, towels,
batteries, earplugs, brushes, boots, tongs, tools, scales in fact over eight hundred
items. NASA has created a twenty two page document listing everything on the moon
which you can download and peruse for yourself but there are also some things
that you think they would like to bring back like the Hasselblad cameras which
were used to take on average fifteen hundred photos each but no they left
behind 12 of the 14 taken on the Apollo missions. The astronauts were instructed
to bring back just the film canisters and leave the cameras to make room for
rock samples, This allowed an extra 25 kilograms of rocks to be brought back
over six missions in place of the cameras. Of course some things were just
far too big to bring back like the three lunar Rovers along with their TV cameras
they were left behind to film the ascent from a moon by remote control on earth.
There was also a gold-plated telescope, the only one to make observations from a
surface of a celestial body other than the earth. Other things left behind were
symbolic in nature and were not always officially sanctioned. We all know the
U.S. flags but Apollo 11 also left behind a gold olive branch as a
representation of peace. An Apollo 1 patch to honor the crew of Grissom, White
and Chaffey who died in a fire during testing and medals given to the families
of the deceased cosmonauts Gagarin and Komarov. There is also the moon memorial
disk which contained the goodwill statements by President Eisenhower,
Kennedy, Johnson and Nixon and messages from the leaders of 73 countries from
around the world. The disc was made using the same techniques as early integrated
circuits and is the size of a U.S. 50-cent coin with the writing visible
using a microscope. On Apollo 15 a nine centimeter statue called "Fallen Astronaut" along with a plaque commemorating the 14 US and Soviet
astronauts which died during training was unofficially placed on the moon by
David Scott and on Apollo 16 Charlie Duke left a
photo of himself his wife and two children on the surface. On the back he
wrote "This is the family of astronaut Charlie Duke from Planet Earth
who landed on the moon on April 20 1972" During and after the Apollo missions the
Soviets continued with their remote-controlled lunokhod Rovers 1
and 2 in 1970 and 1973. Lunokhod 2 operated for four months traveling 42
kilometers and sending back 86 panoramic images and 80,000 TV pictures. Since then
there have only been satellites from the US, Japan, India and China most of which
are which have ended up on the surface until December 2013 when the Chinese
became only the third country to soft land on the moon with the Chang'e 3 and the Yutu or Jade rabbit Rover. Although the rover succumbed to a
mechanical abnormality probably caused by the lunar dust after two months, the
lander which is powered by radioisotope thermoelectric generator and solar cells
was still in contact with the ground control some four and a half years after
it landed and in theory its power supply could last for 30 years. So what will
happen to the things left on the moon. Some say that with no erosion, no wind,
rain or volcanic activity they will be there long after the human race has come
to an end in the millions or even billions of years into the future but
they are forgetting a few things. Firstly the lunar dust, it covers the entire moon
and was created and still is being created by meteor impact. Although
there is no wind to move it around it becomes electrostatically charged from
the sun's ultraviolet and x-ray radiation. This causes it to levitate and create a
very thin atmosphere of dust constantly rising and falling around the
terminator' line as it sweeps across the surface from lunar day to lunar night.
Recent observations and experiments show that the dust builds up at a rate of
around about one millimeter per thousand years. Now that sounds like a
tiny amount but in a million years all the items on the moon would be under a
meter of dust and that's assuming we didn't do anything to make it worse. If
we start mining on the moon then the amount of dust raised will be much much
more and with only one-sixth gravity and no air resistance it could also travel
a very long way. Then there is the Sun with no protective atmosphere like the
earth anything on the surface is exposed to the full force of the sun's
ultraviolet, x-ray and ionizing charged particles just look at its effect here
on earth on paint pigments and photos that have been left out in the Sun. That
lack of atmosphere also means there is almost no temperature regulation so in
direct sunlight the surface can reach a 127 C
and at night it can drop to minus 173 C The thermal stress of that 300
degree temperature range would also take its toll on anything left there. The
photo that Charlie Duke left 47 years ago is probably completely bleached by
now as are the u.s. flags and pigments and painted surfaces will have degraded
and is also the sandblasting effect of micro meteorites hitting objects
directly or nearby and lunar dust which is highly abrasive. So while they may
well in some ways last a lot longer than they would do compared to being left
outside on earth, they will meet the same fate and eventually crumble to dust. One
of the reasons for Apollo leaving so much stuff on the moon was the limited
weight they could carry back in the ascent module with every kilogram making
a difference they had to choose what to bring back and what to leave these were
just some of the myriad of problems that had to be solved often with very short
notice on the missions themselves not only for Apollo but for every lunar
mission that's ever been attempted. If you like to challenge yourself then our
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