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
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