Apollo @40

Forty years ago on 20th July man landed on the Moon and returned a further five times until 1972, a feat never since matched.

It was US president John F. Kennedy's lasting legacy to successfully land a man on the Moon and return him safely to Earth and has been one of humanity's greatest achievements.

It had all begun with this popular Democratic party president who would not know his life would end three years after he made the speech that launched the Apollo rockets and spacecraft.

From May 1961 when president Kennedy announced the plan to go to the Moon “within this decade”, money was no object.

That same year NASA’s designs for the three crew Apollo spacecraft were on show, contracts were awarded and by November the 162ft tall Saturn C-1 was flight tested.

But the Saturn V, then known as the C-5, was still on the drawing board and in competition with the larger Nova class booster. Nova eventually would be dropped in favour of the Saturn V.

But after seven years of technical progress the decadal challenge looked unlikely to be won when in January 1967 a ground test capsule fire killed the Apollo 1 crew. And then the second test launch of the Saturn V had upper stage engine problems.

But the third Saturn V test flight, Apollo 8, saw its crew Frank Borman, James Lovell and William Anders go around the Moon and back. This gamble after so much tragedy succeeded and then the countdown to the historic first step in July 1969 went largely as planned.

In the other sections of this 40th anniversary celebration of Apollo find out about the crew that set off on their journey to the Moon in July forty years ago this week, the rockets and spacecraft and computers that got them there and back and NASA’s 21st century plans to go back to the Moon and beyond. 

Saturn V Rocket

The Saturn V’s first manned flight, Apollo 8, which sent astronauts around the Moon, was only its third launch.

The second launch, Apollo 6, with an unmanned Apollo spacecraft, had even seen a failure of two of the second stage’s five engines but NASA decided to go ahead with Apollo 8 anyway.

Saturn V’s first stage Rocketdyne F-1 engines, of which it had five, were originally developed for a larger Nova class booster NASA had planned. NASA is using an updated version of the Saturn V third stage engine, J-2, called the J-2X for the space agency’s new Ares I crew launch vehicle upper stage.

Apollo Command Module

The three Apollo astronauts would ascend from the Earth and return to its surface in the command module.

The Apollo spacecraft, consisting of the Command Module (CM) and Service Module (SM), used its SM propulsion system to enter lunar orbit and return to Earth from the Moon.

Using fuel cells to provide power for the SM’s electrical systems during the eight to nine day journey it was an explosion in one of these cells that required the Apollo 13 crew to abort the mission and return to Earth.

Forty years on the CM’s heat shield is being used again, with a slight change in its chemical formula, for NASA’s new Orion crew exploration vehicle.

Apollo Lunar Lander

Broadly designed by November 1962 the contract for the Lunar Excursion Module, as it was originally known or just ‘the bug’, was awarded to Grumman in March 1963. The contract was for 11 flight vehicles.

The only aerospace vehicle ever designed to land people on another celestial body, the Lunar Module was flown to the Moon eight times, once to within 50,000ft of the Moon’s surface on Apollo 10, six times landing there from Apollo 11 to Apollo 17 and once it acted as a life boat, for the crew of Apollo 13, when the Command/Service Module was damaged by an explosion. 

Project Apollo's main objective was to successfully land a man on the Moon in the 1960s. Out of NASA's chosen few, two astronauts got their first class tickets to outer space and to be the first men to land on the Moon in July 1969. The third member of the crew, Michael Collins, stayed in the Apollo spacecraft orbiting the Moon.

Here are biographies of the three Americans.

Neil Armstrong

Neil Armstrong, born on August 5, 1930, in Ohio, joined the US Navy as a pilot in 1949 and stayed until 1952.

In 1955 he graduated from Purdue University in aeronautical engineering. That year he joined the NACA Lewis Flight Propulsion Laboratory (now the NASA Lewis Research Centre) where he was involved in the flight programmes of fighter and bomber aircraft.

NASA selected him in 1962 for astronaut training and he became back-up command pilot for the Gemini 5 flight, and then command pilot on Gemini 8.

In Flight International published 17 July 1969, and by way of introducing the Apollo 11 astronauts, Flight wrote: "The height of his flying career was undoubtedly his association with the X-15 programme.

But of course, Armstrong reached greater heights as spacecraft commander for Apollo 11, the first manned lunar landing mission, when he gained the distinction of being the first man to land a craft on the moon and first to step on its surface.

NASA's website records his later career as subsequently holding the position of NASA's Deputy Associate Administrator for Aeronautics where he was responsible for the coordination and management of overall NASA research and technology work related to aeronautics.

He was Professor of Aerospace Engineering at the University of Cincinnati between 1971-1979. During the years 1982-1992, Armstrong was chairman of Computing Technologies for Aviation, Inc. which develops flight operations management systems.

Edwin Buzz Aldrin

Buzz Aldrin was born in New Jersey on 20 January 1930. He was educated at the U.S. Military Academy at West Point, entered the United States Air Force in 1951 and trained as a pilot and  flew F-86s in combat missions in Korea.

Aldrin became an astronaut during a NASA selection process in October 1963. In November 1966 he orbited aboard the Gemini 7 spacecraft, a four day 59-revolution flight that successfully ended the Gemini programme. On Project Gemini, Aldrin became one of the key figures working on the problem of rendezvous of spacecraft in Earth or lunar orbit, and docking them together for spaceflight. Without these skills Apollo could not have been successfully completed.

Aldrin had a Ph.D. in astronautics from Massachusetts Institute of Technology, making him ideally qualified. Systematically and laboriously, Aldrin worked to develop procedures and tools necessary to accomplish space rendezvous and docking.

He was also a central figure in devising the methods necessary to carry out extravehicular activities (EVA) of astronauts outside their vehicles. That, too, was critical to the successful accomplishment of Apollo.

Aldrin was chosen as a member of the three-person Apollo 11 crew and was the second American to set foot on the lunar surface. He and Apollo 11 commander Neil Armstrong spent about twenty hours on the Moon before returning to the orbiting Apollo Command Module.

The spacecraft and the lunar explorers returned to Earth on 24 July 1969. In 1971 Aldrin returned to the Air Force and retired a year later. In his book Return to Earth (1970), Aldrin recounted the flight of Apollo 11. In another book Men from Earth (1989), Aldrin discussed the entire space race between the United States and the Soviet Union. He has been an important analyst of the space programme since the 1960s. He lives near Los Angeles, California.

Michael Collins

Collins was born in Rome, Italy on 31 October 1930. Like "Buzz". he too attended U.S. Military Academy at West Point and he served as a a fighter pilot and an experimental test pilot at the Air Force Flight Center, Edwards Air Force Base, California. From 1959 to1963 he logged more than 4,200 hours of flying time before he joined NASA.

Chosen to by NASA to be an astronaut, he and served as a pilot on the three-day Gemini X mission, launched in July 1966. His second flight was as Command Module pilot of the historic Apollo 11 mission in July 1969. He remained in lunar orbit while Neil Armstrong and Buzz Aldrin became the first people to walk on the Moon but his role in the Apollo mission earned him many awards and accolades.

In January 1970, Collins left NASA to become the Assistant Secretary of State for Public Affairs. A year later he joined the Smithsonian Institution as the Director of the National Air and Space Museum where he remained for seven years.

In  1978, Collins became Under Secretary of the Smithsonian Institution. In 1980, he became the Vice President of the LTV Aerospace and Defense Company, resigning in 1985 to start his own firm.

Collins has logged 266 hours in space, of which 1 hour and 27 minutes was spent in extravehicular activities (EVA). He published his experiences in the space programme in several books. In 1988, he wrote Liftoff: the Story of America’s Adventure in Space. Today he is an aerospace consultant and writer.

It took the Apollo spacecraft three days to reach lunar orbit.

Although the theoretical physics of travelling to the Moon had been laid down before the advent of the Apollo missions, this was the first time a series of manned missions had put the theory into practice.

The Moon is 385,000km (239,100miles) away and to reach it any spacecraft must first have reached a speed of about 28,175km/h (17,500mph) just to get to Earth orbit and then increased its velocity to over 35,000km/h to leave our world behind and arrive at its natural satellite.

Once launched from the Earth’s surface the Apollo craft initially orbited the planet, travelling fast enough that the gravitational pull did not drag it back to the surface.

Orbits can be circular or ellipses. The ellipses have a point closest to the surface, called the perigee, and the point furthest from the surface, called the apogee.

Escaping the Earth’s gravity field to travel further would bring a spacecraft into the orbit of the Sun with its huge gravitational field but to get to the Moon a different route was taken.

Routes to the Moon, or any celestial body, are called a trajectory. While different trajectories can be used to reach the Moon over a preferred period of time and fuel expenditure, Apollo 11 followed a free-return circumlunar trajectory.

A free-return meant that the trajectory saw it travel around the Moon, due to the satellite’s own gravitational field, and then return to Earth. The Apollo 11 spacecraft started from a circular orbit around the Earth with the goal of a circumlunar, close approach, with the Moon.

When the spacecraft’s engine was fired the aim was to reach a point where the spaceship met the Moon as it travelled on its orbit around the Earth. This required firing the rocket engine at the right time to leave Earth orbit. This timing is referred to as a launch window.

The rocket firing is called translunar injection (TLI) and during TLI Apollo’s spacecraft increased its velocity from 28,062km/h to 39,000km/h to leave Earth orbit. Once on this curved path, to ensure that the trajectory was followed midcourse, corrections were made by firing the Apollo spacecraft’s engine a number of times.

Eventually the spacecraft reached the Moon and a lunar orbit insertion burn was made, firing the engine to put the spacecraft into an elliptical Moon orbit. Later a second firing put the spacecraft into a circular orbit.

It is hard to appreciate the technical challenges involved in putting a man on the Moon, but 1960s computer technology played a fundamental role.

By today's standards, the IT NASA used in the Apollo manned lunar programme was basic. But while they were no more powerful than a pocket calculator, these ingenious computer systems were able to guide astronauts across 356,000km of space from the Earth to the Moon and return them safely.

The lunar programme led to the development of safety-critical systems and the practice of software engineering to program those systems.

Much of this knowledge gleaned from the Apollo programme forms the basis of modern computing.

Apollo Guidance Computer

The lunar mission used a command module computer designed at MIT and built by Raytheon, which paved the way to "fly by wire" aircraft.

The so-called Apollo Guidance Computer (AGC) used a real time operating system, which enabled astronauts to enter simple commands by typing in pairs of nouns and verbs, to control the spacecraft.

It was more basic than the electronics in modern toasters that have computer controlled stop/start/defrost buttons. It had approximately 64Kbyte of memory and operated at 0.043MHz.

IBM computers on Apollo 11

Along with the APG, mainframes were also heavily used in the Apollo programme. Over 3,500 IBM employees were involved.

At the time, IBM described the 6Mbyte programmes it developed, to monitor the spacecraft's environmental and astronauts' biomedical data, as the most complex software ever written.

Even the simplest software today would far exceed the technical constraints the Apollo team worked under.

That a USB memory stick today is more powerful than the computers that put man on the Moon is testimony to the relentless pace of technological development.

However, the Apollo programme proved that computers could be entrusted with human lives. Man and machine worked in unison to achieve something that 40 years on, has yet to be surpassed.

• Continue reading article courtesy of Flightglobal sister title Computer Weekly...

To this day only 12 men have walked on the surface of the Moon. However revisiting Earth's satellite is an irresistible topic for all of those inspired by dreams of exploration and new frontiers. How soon will these dreams become a reality?