Apollo 8: Houston, we have a deadline
08 December 2015
First full picture of Earth taken by Apollo 8 or indeed anybody
As we enter into the last slope towards the Christmas holidays, most of us will be experiencing those last-minute project deadlines before we can scuttle off to the world of turkey sandwiches, ‘Home Alone’ and the annual St Stephen’s night pub crush.
To soothe over these nerves, there was one project team that had to meet one the worst deadlines of all – getting to the moon for Christmas Eve. Generally, people know the story of Apollo 11 (first astronauts to land on the moon) and Apollo 13 (first astronauts to really, really not land on the moon) but Apollo 8 is largely forgotten despite the big achievements it achieved in a matter of months, particularly during the mission itself during Christmas 1968.
The NASA Apollo missions were geared towards getting a man on the moon by the end of the 1960s. The first few missions involved launching rockets into orbit followed by launching people with these rockets into orbit. But Apollo 8 would be a significant jump in scale in that it would be the first mission to leave Earth and orbit humans around the moon.
The schedule for this was brought forward by three months when the lunar lander wasn’t fully developed for the Apollo 9 mission. Therefore, training and resourcing for this had to be compressed significantly. This was going to be a build on Apollo 7 which sent the same crew and missions to just orbit Earth.
It was part of the developing NASA philosophy whereby any new mission should build on the achievements of the previous trip rather than just repeating it. In September, the crew spent seven hours training for every hour of the mission including doing simulations such as flying the spacecraft if contact was lost with Earth during lunar orbit.
There was also pressure from the Russians who were already experimenting with moon orbit missions after sending an unmanned craft into moon orbit in late October of that year. Subsequent rumours of a tortoise being sent into orbit prior to humans were also being discussed in different quarters.
Not for the first time, the US was slow to react to a perfect joke set-up by not sending up a hare in its competing spacecraft to reach the moon. Instead the US team opted with a crew of Frank Boorman (aeronautical engineer), Jim Lovell (the only man to fly to the moon twice but not land there) and William Anders (nuclear engineer).
The engine – Saturn V
Central to this was the recently developed Saturn V rocket created by Werner Van Braun. Saturn V is big: taller than Big Ben and slightly shorter than the Dublin spire, it contains enough fuel to fill more than 250 Olympic-sized swimming pools. The five fuel pumps within have the equivalent horsepower of six diesel train engines.
At more than 14,0000 tons and delivering a thrust of 1,400kn, it is the most powerful rocket engine ever developed. By comparison, the absolute maximum thrust of a modern Airbus A380 is about 280kn. Despite all this, the rocket itself would only be used for less than 20 minutes on a typical mission. Things didn’t start so well for the rocket when it failed twice to ignite from the platform at T=0 seconds on its first launch.
Thus, a technician was dispatched in a car to the launch pad, took the elevator to the top of the rocket and “slapped some tape on a loose piece of the spacecraft cover, and came back down”. Houston spacecraft experts decided that the tape was good enough to hold through launch. The rocket launched on the third attempt.
There are also numerous problems associated with rocketry that can’t be discussed in a simple 1,400-2,000 word article. Chief among these are pogo oscillation (the effect of bouncing/tensioning of the rocket if the rocket blast is not constant), the heat contrast between cold liquid hydrogen fuel and the heat blast generated nearby and then the actual problem of maintaining trajectory once the rocket has launched.
Another problem rocket engineers complain about (bless) is the problem of providing enough power to lift a rocket off the ground. But this extra power means extra fuel which means extra weight which means even more extra power to get this extra weight off the ground. It is not easy
Another problem the Apollo 8 project team faced was figuring out the interaction between the moon, the Earth, and its gravity forces. To the casual observer, the moon orbits around the Earth, so launching the rocket in the location where the moon was going to be rather than its location at launch time was an initial problem.
Similarly, when the rocket had to blast again in the direction of Earth, it had to calculate where the Pacific landing site was going to be as it re-entered Earth. This introduced the concept of slingshotting in that the spacecraft had to accelerate at a certain point in earth orbit so that it would leave in a tangential line towards the moon and then be ‘captured’ by moon gravity on the other side.
This was then repeated for the return leg towards Earth. Remember, this involved selecting these acceleration blasts between the moving objects of the Earth and the moon at key moments. This would also involve the highest speed ever travelled by humans: 10,822 m/s. Seatbelts were provided.
Apollo 8 launched on December 21 with the aim of getting to moon orbit for Christmas Eve. Passing across space, the craft had to be rotated constantly to allow even heat distribution. With one side heating to up to 150 degress Celsius and the other -200 degrees Celsius, constant rotation was required to avoid cracking of the heat panels and the spacecraft itself.
Upon entering the moon’s orbit, a calculated blast was required to sync with the orbit of the moon. Too much and the craft would have overshot the moon and into outer space, too little and the craft would have fallen short and crash landed into the moon. Once getting into orbit, the crew describes the moon’s surface in a detailed but blunt manner:
“The Moon is essentially grey, no colour; looks like plaster of Paris or sort of a grayish beach sand. We can see quite a bit of detail. The Sea of Fertility doesn’t stand out as well here as it does back on Earth. There’s not as much contrast between that and the surrounding craters. The craters are all rounded off. There’s quite a few of them, some of them are newer.”
Then, with an audience of an estimated one billion globally, a broadcast was made on Christmas Eve to witness Earthrise where the crew read from the book of Genesis and then wished everybody on Earth a happy Christmas
The following day, they had Christmas dinner on board and rather than the usual liquid packs astronauts typically had to consume, they were given individual packs of real turkey, real cranberry sauce and … real brandy. Upon seeing the latter items, Boorman told the crew to “put them back”. To this day, they remain unopened and lie on NASA director Bob Gilruth’s mantelpiece in Dickinson, Texas. Two days later, they splashed down in the Pacific on December 27, closing 1968 with a highly positive mission and a first for the human race.
After which, ‘Time’ named them 1968’s Men of the Year after a difficult 12 months of rioting in America and Paris; the assassinations of Martin Luther King Jr and Robert F Kennedy; the Prague Spring; and the Vietnam War turning from a quick war into a long torture for the US. Boorman would later receive a telegram that read simply: “Thank You Apollo 8, You saved 1968.”
The achievements of this were many and highlighted the many benefits of space exploration at the time. This was the first experience of long-range TV broadcasts which required portable cameras to be developed, the first humans to see the entirely of the Earth, and the first to see the far side of the moon. Bizarrely NASA was also sued by an atheist wishing “public prayer to be banned from space”.
The year 1969 was remembered as the year of the moon landing but it was in Christmas 1968 that real strides in technology was made with this mission. New durable materials were developed that subsequently were used in other vehicles and buildings. This was also the early stages of nanotechnology where minimising objects such as cameras and computers were a necessity before they could be taken on board the spacecraft.
It was also a great test in project communication and decision making with numerous problems such as crew flight sickness, communication blackouts and problem solving while travelling at more than three times the speed of sound. On Christmas Day when NASA were anxiously awaiting confirmation if the acceleration blast to send the rocket out of lunar orbit and back to earth had worked, Jim Lovell, after a few moments of radio silence, responded: “Roger, please be informed there is a Santa Claus.”http://www.engineersjournal.ie/2015/12/08/apollo-8-the-ultimate-christmas-deadline/http://www.engineersjournal.ie/wp-content/uploads/2015/12/aaaaapollo1-1024x905.jpghttp://www.engineersjournal.ie/wp-content/uploads/2015/12/aaaaapollo1-300x300.jpgTechaeronautical,space