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Deep Field

In depth topics

Apollo missions

Impacts in space

The search for life


July 2019 sees the 50th anniversary of Neil Armstrong stepping on to the Moon - Apollo 11

July 2019 sees the 50th anniversary of Neil Armstrong stepping on to the Moon - Apollo 11

Apollo Missions

 The goal - “Of landing a man on the Moon and returning him safely to the Earth”

President J F Kennedy stated the purpose of the Apollo Moon missions on 25th May 1961 –
the target was to achieve his goal

 “before this decade is out”

The Apollo flights would create a series of firsts:-

The first humans to see the ‘far side’ of the Moon
The first humans to see ‘Earth rise’
The first man to walk on the Moon
The return of large quantities of lunar rock to Earth for analysis
The first scientific experiments set up by humans on another Solar System object

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The bid to get man to step on the Moon came at a high price for the US people. The Apollo missions got off to the worst possible start. Apollo 1 saw disaster on 27th January 1967 - a fire on the launchpad killed the 3 astronauts as they were working in the command module.


Remembering 3 brave men and their families

In the early days of space flight, the command module was filled with pure oxygen. A short circuit meant that exposed hot wires ignited a fire and sadly the 3 astronauts were trapped and perished. Future Apollo missions were immediately suspended as engineers worked to discover the cause of the fire. Improvements were suggested and trials undergone to ensure no further Apollo tragedies would happen. The Apollo team was under pressure to deliver President Kennedy’s goal “before this decade is out”.

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An unmanned flight on 5th July 1966 is sometimes seen with the Apollo 2 designation – a 6 hour test flight to study the effect of weightlessness on the fuel system and trial a new instrumentation system

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An unmanned flight on 25th August 1966 is sometimes seen with the Apollo 3 designation – a brief flight to try out the Saturn rocket and to test the heat shields on a simulated re-entry from the Moon


The huge Saturn V rocket -

the Vehicle Assembly Building in the background is 50 stories high!

The rocket is on the way to the launchpad at about 1km per hour


These Apollo missions saw the end of unmanned missions -
Apollo 7 was the first launch to have 3 astronauts on board, but not using the huge Saturn 5 rocket

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The very first TV live from space –
Schirra and Eisele in touch with planet Earth

The interest created by the first TV broadcast from space was amazing -
the public were excited by the prospect of man on the Moon!

Apollo 8 was the huge step in the Apollo missions. This was to take astronauts further from Earth than ever before, around the far side of the Moon.


The famous Apollo 8 decal showing the flightpath the astronauts would take around the Moon

First manned visit to the ‘far side’ of the Moon

First humans to be out of contact with Earth
(no radio contact whilst behind the Moon)

The first humans to see ‘Earth rise’


Earthrise - one of the most famous photographs ever taken


NASA image AS08-14-2383 was taken by Bill Anders on 24th December 1968. The radio commentary shows the excitement of the astronauts as they came back into touch with mother Earth:-

Anders: Oh my God! Look at that picture over there! There's the Earth coming up. Wow, that's pretty.
Borman: Hey, don't take that, it's not scheduled. (joking)
Anders: (laughs) You got a color film, Jim? Hand me that roll of color quick, would you...
Lovell: Oh man, that's great!

Everything was working well with the Apollo missions and any problems that did arise were addressed quickly so that future missions could be launched on schedule. Apollo 9 and Apollo 10 paved the way to the Moon landings:-


So close to the lunar surface –

just 15km away but the

Lunar Module ‘Snoopy’
could not land on the trial run.

The picture was taken from the
Lunar Module looking towards the
Command Service Module

Although Commander Tom Stafford was so close to the lunar surface, he never walked on the Moon. To this day, he is the closest a person has been to the Moon without ever setting foot on the surface. Command Module pilot John Young became the 9th man to walk on the Moon as Commander of the Apollo 16 mission in 1972. Lunar Module pilot Gene Cernan is famously the last person to walk on the Moon, leaving the surface of the Moon on 14th December 1972. The following report, made by Dheepthika Laurent for France24 at the time of Gene Cernan’s death, is a special reminder of a great man and his words back to Earth from the surface of the Moon were a fitting closure to the Apollo programme.


The famous launch of the Saturn V rocket carrying Neil Armstrong, Buzz Aldrin and Michael Collins aboard the Apollo 11 mission - with the iconic countdown of Jack King, the NASA Public Affairs Officer


The Apollo 11 Decal showing t

he Eagle lunar lander touching down at the
Sea of Tranquility

“Here men from the planet Earth first set foot upon the Moon - July 1969 A.D.
We came in peace for all mankind”

The quote was written on a plaque left on the Moon on the lunar lander

The most famous space mission of all time saw man set foot on the Moon and President Kennedy’s goal had been achieved, as all returned safely.  The landing was even more incredible because Neil Armstrong had less than 30 seconds of fuel left to get the Lunar Module down on to the surface of the Moon.  Weight was so critical that the 2 astronauts did not have seats in the Lunar Module – they stood throughout the flight down!

The official NASA film of the Apollo 11 flight ‘The Eagle has Landed’ shows the major moments of the mission. Key times are:-

Separation of the Command Module (Columbia) and the Lunar Module (Eagle) : 7 minutes 02 seconds into the video stream

Landing sequence on the Moon : 9 minutes 10 seconds into the video stream

Armstrong setting foot on the Moon : 12 minutes 06 seconds into the video stream

Launch from the lunar surface : 18 minutes 00 seconds into the video stream

The first thing that Neil Armstrong had to do once he was on the surface of the Moon was to fill a bag with lunar rocks – so if Armstrong and Aldrin had to leave in a hurry, geologists would have samples to analyse allowing them to work out how the Moon was formed.


The ‘Early Apollo Scientific Experiment Package’ of Apollo 11 placed a mirror on the Moon to accurately measure the distance of the Earth to the Moon.  This was carried out by timing the return time of a laser beam fired from Earth which reflected off the mirror – this proved that the Moon is moving way from Earth at 3.8cm a year.  Jerry Wiant fired the laser from the McDonald Observatory, Texas. The mirror is still used to this day.


Experiments included the following:-

Magnetometer – to measure the magnetic field of the Moon
Seismometer – to measure Moon quakes for finding out the internal structure of the Moon
Particle detector

– for catching solar wind particles

The ALSEP central station for Apollo 14 is shown

The ‘Apollo Lunar Surface Experiments Packages’ (ALSEPs) were a collection of experiments placed on the lunar surface by Apollo 12 to 17 (except for Apollo 13 which failed to land)

The landing zones for the Apollo missions were chosen with the aid of geologists - the most important being the famous Eugene Shoemaker, who trained all the astronauts at Meteor Crater. When Gene died, his ashes were placed on board the Lunar Prospector spacecraft and when the craft’s mission was ending, it plummeted down into the South Pole–Aitken basin in a study to see if water ice was present on the Moon. Gene Shoemaker’s unfulfilled dream of going to the Moon had been realised.

Apollo 11 had to land near the equator in order to keep the weight of fuel to a minimum. Later Apollo missions could carry extra fuel loads once the performance of the craft had been assessed, in order to power the lunar lander away from the equator. As well as landing near the equator, the Eagle lunar lander had to land on a lunar sea where the ground would be reasonably level. The bonus for the Sea of Tranquility was that it was close to a scatter ray from the crater Tycho (much further south) and there was an outside chance that rocks from the Tycho region might be picked up.



Mission Site Location Latitude Longitude Date of Landing

Apollo 11 Mare Tranquillitatis 0°41'15" N 23°26' E July 20, 1969
Apollo 12 Oceanus Procellarum 3°11'51" S 23°23'8" W Nov. 19, 1969
Apollo 14 Fra Mauro 3°40'24" S 17°27'55" W Feb. 5, 1971
Apollo 15 Hadley-Apennines 26°06'03" N 03°39'10" E July 30, 1971
Apollo 16 Descartes 8°59'29" S 15°30'52" E April 21, 1972
Apollo 17 Taurus-Littrow 20°9'55" N 30°45'57" E Dec. 11, 1972


Pete Conrad and Al Bean larked around on the surface of the Moon and the American tax-payers, already concerned about the huge cost of the Apollo programme, were even more concerned that they were sending astronauts to the Moon who were messing around. This was not fair because these brave men were putting their lives on the line in what were very dangerous missions, each of which had the potential for disaster - as would be seen in the very next Apollo 13 mission. My all-time favourite quote from space was made by Pete Conrad as he stepped on to the surface of the Moon. But first, the background to the story. The picture shows Pete Conrad going down the ladder of the Intrepid lunar lander -


Pete Conrad was having lunch with an Italian journalist, Oriana Fallaci, who believed the astronauts had to say what they were told when they stepped on to the lunar surface. Pete Conrad was quite a small man at 5 foot 6 inches and the last step off the ladder was a long way. Pete won his 500 dollar bet with Oriana when his agreed words were famously called out as he left the ladder…

115:22:16 - the time into the mission when Pete took his step on to the Moon


Then came the incredible Apollo 13 mission that saw the whole world holding its breath as mission control struggled to overcome the near disastrous problems faced in returning the 3 man crew back to Earth. The famous “Failure is not an option” quote of Lead Flight Director Gene Kranz turned the expedition into the “successful failure”. The whole NASA team came up trumps to achieve what they did. Remarkable!


Jack Swigert took the place of Tom Mattingly right at the last minute – the fear was that Tom Mattingly had been exposed to German measles and could become ill during the mission.  He never did get German measles!

The Apollo 13 problem began a long time before the actual flight began. A really unfortunate sequence of events all added up together to leave the Apollo 13 crew in peril. The following time-line runs through the sequence (and it shows how incredibly thorough NASA were in recording engineering events and how incredibly thorough the search was in finding the reason for the Apollo 13 malfunction).

The Apollo 13 malfunction was caused by an explosion and rupture of oxygen tank no.2 in the service module. The explosion ruptured a line or damaged a valve in the no.1 oxygen tank, causing it to lose oxygen rapidly. The service module bay no.4 cover was blown off (seen in the photograph below). All oxygen stores were lost within about 3 hours, along with loss of water, electrical power and use of the propulsion system.

The Apollo 13 damaged Service Module - seen for the first time by the astronauts and ground crew just prior to re-entry.  All were shocked by what they saw - Commander Jim Lovell said "There's one whole side of that spacecraft missing"

The Apollo 13 damaged Service Module - seen for the first time by the astronauts and ground crew just prior to re-entry.
All were shocked by what they saw - Commander Jim Lovell said "There's one whole side of that spacecraft missing"

Pre-flight testing showed that the original operational 28 volt DC power of the command and service modules would have to be redesigned to also run off the 65 volt DC ground power at Kennedy Space Centre. Engineers at the North American manufacturing company redesigned all the electrical components to cover this upgrade - EXCEPT FOR ONE COMPONENT.

October 1968
Oxygen tank no.2 was at North American Aviation in Downey, California. As the tank was removed from Apollo 10 for modification it was dropped during the extraction by 2 inches, slightly jarring an internal fill line. The tank was replaced with another for Apollo 10 and the exterior inspected. The internal fill line was not known to be damaged and this tank was later installed in Apollo 13. 


A diagram showing oxygen tank no.2

The oxygen tanks were highly insulated spherical tanks which held liquid oxygen with a fill line and heater running down the centre. The no. 2 oxygen tank used in Apollo 13 (North American Rockwell; serial number 10024X-TA0008) was the one that had originally been installed in Apollo 10. All components had been upgraded to accept 65 volts EXCEPT THE HEATER THERMOSTATIC SWITCHES which were overlooked. These switches were designed to open and turn off the heater when the tank temperature reached 27ºC. (Normal temperatures in the tank were -184ºC to -73ºC). 

March 1970
During pre-flight testing of Apollo 13, tank no.2 showed anomalies and would not empty correctly, possibly due to the damaged fill line. On the ground, the tanks were emptied by forcing oxygen gas into the tank and forcing the liquid oxygen out, in space there was no need to empty the tanks. The heaters in the tanks were normally used for very short periods to heat the interior slightly, increasing the pressure to keep the oxygen flowing. It was decided to use the heater to "boil off" the excess oxygen, requiring 8 hours of 65 volt DC power. This probably damaged the thermostatically controlled switches on the heater, designed for only 28 volts. It is believed the switches welded shut, allowing the temperature within the tank to rise to over 500ºC. The gauges measuring the temperature inside the tank were designed to measure only to 27ºC, so the extreme heating was not noticed. The high temperature emptied the tank, but also resulted in serious damage to the teflon insulation on the electrical wires to the power fans within the tank. 

About 03:06 UT on 14 April 1970 (10:06 PM, April 13 EST)

The Apollo 13 crew received the message from Houston Control that would change their lives forever

55:52:58 - CapCom (Jack Lousma): "13, we've got one more item for you, when you get a chance.  
We'd like you to stir up the cryo tanks"

Nearly 56 hours into the mission, the power fans were turned on within the tank for the third "cryo-stir" of the mission, a procedure to stir the liquid oxygen slush inside the tank which would tend to stratify. The exposed fan wires shorted and the teflon insulation caught fire in the pure oxygen environment. This fire rapidly heated and increased the pressure of the oxygen inside the tank and may have spread along the wires to the electrical conduit in the side of the tank, which weakened and ruptured under the pressure, causing the no.2 oxygen tank to explode. This damaged the no.1 tank and parts of the interior of the service module and blew off the bay no.4 cover.

55:55:20 - Swigert: "Okay, Houston, we've had a problem here"

55:55:28 - Lousma: "This is Houston.  Say again please"

55:55:35 - Lovell: "Houston, we've had a problem" 


The spacecraft was flying fast towards the Moon about 200,000 miles from Earth (flying very fast away from home). The two service module oxygen tanks were either empty (no.2 tank) or rapidly emptying (no.1 tank). Two of the three fuels cells of the service module had failed and with it the command module had lost its supply of electricity, light and water.

Just over one hour after the explosion and with only 15 minutes of power left in the command module, the crew moved into the lunar module - which would act as their lifeboat - it would save their lives. There was more than enough oxygen to last to allow the astronauts to get back to Earth. Power (to be supplied from the lunar module, which would now not be needed to land on the Moon as the mission was aborted) was in very short supply. A command module battery was teetering on failing - if it failed there would not be enough power to return the craft back to Earth. Calculations for the availability of water estimated that the crew would run out of water just 5 hours before re-entry to Earth (in a mission now expected to last a total of 151 hours). The carbon dioxide levels were a worry. There were plenty of lithium hydroxide canisters for the removal of carbon dioxide breathed out by the astronauts, but the square canisters from the command module were not compatible with the round openings in the lunar module - something had to be done or the astronauts would suffocate.

AND THEN THE BIG QUESTION - "How to get back safely to Earth?". The exact alignment of the craft needed to be known to ensure that fuel burns put the craft on the correct flightpath back to Earth. Commander Jim Lovell needed to use a sextant device (the Alignment Optical Telescope) to find a suitable navigation star. However, due to the explosion, a mass of debris from the ruptured service module made it impossible to sight real stars because of all the ‘false stars’ - glinting pieces of debris.


Before the explosion at 30 hours 40 minutes, Apollo 13 had made the normal midcourse correction, which would take it out of a free-return-to-Earth trajectory and put it on a lunar landing course. So the only way to get Apollo 13 home was to go round the far side of the Moon and use the Moon’s gravity to swing it back to Earth - but this required a burn of fuel to get the craft on a free-return course, escaping the Moon’s gravitational pull. Lovell rotated the spacecraft to the attitude Houston had requested and when he looked through the Alignment Optical Telescope, the sun (the new navigation star chosen) was close to where it was expected. THE CHEER OF THE YEAR - went up as Lovell and Haise reported they had a fix on the sun. Mission Control in Houston computed a 35 second burn to be fired five hours after the explosion. As they approached the Moon, another burn was computed - this time a long five minute burn to speed up the return home. The long burn took place two hours after rounding the far side of the Moon and would cut the return time by about 9 hours. Mission Control and the crew were on their way home - if they could solve the carbon dioxide problem…

Fred Haise spoke of the fix to the problem of a ‘Square Peg in a Round Hole’

“We would have died of the exhaust from our own lungs if Mission Control hadn't come up with a marvellous fix. The trouble was the square lithium hydroxide canisters from the command module would not fit the round openings of those in the lunar module environmental system. After a day and a half in the lunar module a warning light showed us that the carbon dioxide had built up to a dangerous level, but the ground was ready. They had thought up a way to attach a command module canister to the lunar module system by using plastic bags, cardboard and tape - all materials we had on board. Jack and I put it together - just like building a model airplane. The contraption wasn't very handsome, but it worked. It was a great improvisation - and a fine example of co-operation between ground and space”.


Swigert sitting next to a taped-over double canister and holding one end of a suit nozzle while Fred Haise used both his hands to manipulate the long hose.
Underneath the canister is a ‘mailbox’ built of arched cardboard, which was covered by a plastic bag

CapCom Joe Kerwin led Astronaut Swigert, step by step, for an hour to build a contraption like the one the experts had constructed on Earth. It involved stripping the hose from a lunar suit and rigging the hose to the taped-over command module double canister, using the suit's fan to draw carbon dioxide from the cabin through the canister and expel it back into the lunar module as pure oxygen.

The NASA video shows the flight of Apollo 13 - from launch to the successful return of the astronauts to Earth

Those sleepless hours of the return back to Earth, the condensation all over the inside of the spacecraft (droplets from all surfaces fell as rain as the craft slowed as it hit the atmosphere), the dropping temperature (down to just 3ºC at re-entry), together with the anxiety of the situation… Lack of water (the crew cut intake to 1/5th the normal daily intake) saw the astronauts become dehydrated. Fred Haise suffered a kidney infection as a result of this - which he completely recovered from back on Earth. Lack of food saw a combined loss of 14kg for the 3 men. The crew worked brilliantly through all the discomfort - working in low light levels - with all those at Mission Control and the recovery team to snatch success out of the failure to get to the Moon.


From near disaster to glorious triumph!


The whole world could stop holding its breath!

There was a delay to the Apollo programme after the return of the Apollo 13 crew as reasons for the problems were being sought. As a result, there were no Moon landings during 1970. Apollo 14 was to be directed to the Fra Mauro region of the Moon - the location where Apollo 13 was set to land before the Moon landing was aborted.


Everything went as planned with the Apollo 14 mission - much to the relief of all at NASA - apart from needing 6 attempts to latch the command and lunar modules together on the flight towards the Moon. A few minor glitches prior to landing were sorted out by computer programmers and then the Antares lunar lander set down on the surface of the Moon in a near perfect landing. The importance of landing at Fra Mauro was that rocks that were thrown out from the formation of the Mare Imbrium to the north were found in this region. These rocks were from deep down below the lunar surface and could possibly give clues to the formation of the Moon. The NASA video of the mission tells the story of Apollo 14:-

One special fun time of the Apollo 14 mission was when Commander and original Mercury astronaut Alan Shepard, the first American to fly in space, pulled out a 6 iron golf club and played a few shots - which according to Al Shepard went "miles and miles and miles". Capcom Fred Haise (of Apollo 13) was commenting from Mission Control. This is shown on the following video:-

Apollo 15 would use the first lunar rover to drive around the surface of the Moon. This would allow the astronauts a much greater range in order to carry out scientific studies. The Hadley Rille in the Apennine mountains would prove to be the most scenic of the Apollo landing sites.


Extra Vehicular Activity around

the spectacular Apollo 15 landing site


Dave Scott carried out a fantastic demonstration of proving Galileo’s work on gravity and falling objects - in the most superb location. Standing alongside the Falcon lunar lander, he dropped a falcon feather and a geologic hammer at the same time:-

Apollo 16 was the fifth Apollo landing on the Moon and the landing site in the Descartes highlands would give geologists the opportunity of studying some of the oldest lunar rocks returned to Earth.


A lunar rover was driven around 3 Apollo landing sites. The following video of the Apollo 16 lunar rover has been superbly edited for HD viewing and also the stabilising filter means the wobble of the camera has been allowed for - meaning the picture edges wave around instead of the main view:-

The NASA video ‘Apollo 16 : Nothing So Hidden’ produced shortly after the mission, shows the events of the Apollo 16 mission. This mission was fraught with problems. Only one hour before launch was the all clear given to proceed. As the lunar module separated from the command module and prepared for its descent to the lunar surface, it was brought back to help command module pilot Ken Mattingly overcome problems with gaining the correct orbit around the Moon. The video shows all the technical and scientific staff involved in correcting problems and ensuring the experiments all went to plan. Unfortunately, John Young tripped over a lead which prevented an experiment to study the heat flow in the lunar surface to be carried out. The video shows the beauty of the region - perhaps the Descartes highlands were claiming the most scenic Apollo location. One thing to note is that all the astronauts on the lunar surface found it very difficult to estimate distances. Young and Duke looked close to a large rock and yet they appeared smaller and smaller as they eventually reached their target.

…and so back to Eugene Cernan. Apollo 17 was to be man’s last venture for the Apollo programme. Funding had been cut and the planned Apollo 18, 19 and 20 missions were ditched. Apollo 17 was to be very successful and for the only time a trained geologist walked on the Moon to collect samples using his expert knowledge - Harrison ‘Jack’ Schmitt.


The final Apollo mission to the Moon was to bring samples back to Earth from the Taurus Littrow valley. These samples and the experiments that were set up would give scientists a huge amount of material and data that would help us to understand the way the Moon was formed, its internal structure and chemical make-up and also to help design the tests for future satellites to the Moon in order to find the answers to even more questions about our solar system. The final NASA video of the Apollo missions ‘Apollo 17 : On the Shoulders of Giants’ gives a superb insight into the mission (but also showed that NASA were thinking of life after Apollo - even as the trio of astronauts were flying off to the Moon):-

The film showed the ‘bouncing’ walk that astronauts used and also showed how tricky working in a spacesuit could be - there were a number of stumbles along the way. The location was chosen to bring samples home to Earth of the ‘newer’ rocks of the Moon. The panorama below shows the rover at Shorty crater where an unusual orange rock sample was found:-


A final special image from the Moon was of the last man to set foot on the Moon - Gene Cernan - with the American flag with the Earth in the sky above:-


Thank you to all the Apollo team

Wonderful memories!
We have learnt so much

The disappointment for the astronauts who missed out on a trip to the Moon must have been huge –

  • Jack Schmitt was due to be on board Apollo 18, but was brought into the Apollo 17 crew late on – he was the incredibly lucky one

  • Pete Conrad was due to be Commander of the Apollo 20 mission - but he had already flown to the Moon as Commander of Apollo 12

  • Most unlucky of all was Fred Haise - he missed out with Apollo 13 and was all set to be Commander of Apollo 19

Photographs, video & data used in this Deep Field topic have been provided by the excellent NASA archives about Apollo


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