Alguna vez recordé una acalorada discusión ocurrida a fines de los años sesenta, cuando todavía el colegio Saint George's no se cambiaba a La Pirámide, protagonizada por 'Parrita', el enjuto vendedor de pasteles que se instalaba junto a un enorme ciprés ubicado en lo que hoy es Alférez Real, casi al llegar a Pedro de Valdivia y algunos georgians de los cursos superiores.
La discusión estaba relacionada acerca de la si era versad o no que el hombre había salido al espacio exterior y había puesto pie en la Luna.
Parrita negaba tajantemente, afirmando que todo era un cuento armado en Hollywood para embaucar incautos. Que a él no le venían con payasadas, que era muy fácil engañar a la población, armando un tinglado en un estudio que simulara a los astronautas saltando por la luna, pero que no era verdad.
Los georgians le daban todo tipo de argumentos que no lograban convencer al vendedor de pasteles, quien en lo acaparado de la discusión, despertaba el hambre de los contertulios, quienes, a pesar de que no eran muy barata su dulce oferta, al final igual vendía casi la totalidad de la mercadería de berlines, príncipes y alfajores.
El hecho es que, mirando en perspectiva y desde el punto de vista de un hombre sencillo, a comienzos de los años sesenta parecía más factible que un país como Estados Unidos derrotara a los Vietnamitas del Norte que lograran cumplir con el desafío autoimpuesto por el presidente Kennedy de llevar un hombre a la Luna y traerlo de vuelta antes de que finalizara la década. Paradojalmente esta meta se hizo realidad durante la primera administración Nixon, quien fuera derrotado por Kennedy en las elecciones presidenciales norteamericanas de 1960.
No sólo estaba el exorbitante costo de una empresa como ésta: del orden de veinte a veinticinco mil millones de dólares de la época, algo absolutamente prohibitivo para cualquier nación del mundo, excepto, en aquella época Estados Unidos, motivados por una carrera espacial que iban perdiendo en medio de una crisis de misiles que ponía al mundo en vilo.
Estamos hablando de una empresa inédita en la historia de la humanidad, en que había que fabricar motores, cohetes, módulos, y una infinidad de detalles, millones de partes y piezas y utilizar la mejor gente y la mejor gestión de manera que toda la planificación, ensayos, vuelos, caminatas espaciales, ida y regreso de la Luna coincidiera en el espacio y el tiempo para cumplir con el sueño-desafío.
El elemento de peligro e inseguridad, agudizado por una historia de ensayo y error, contribuyó a la emoción del alunizaje. Antes de los años 60, nadie sabía con certeza si los cohetes algún día podrían llevar a los seres humanos al espacio. Durante los ocho años que median entre 1961 y 1968, avanzamos
desde la visión de un presidente hasta la realidad de un alunizaje.
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Saturn V (some generic specifications)
When the American Space Programme
finally achieved a Moon landing
on 20 July 1969,
the Apollo 11 spacecraft
was launched by
a powerful rocket called Saturn V.
The most powerful rocket ever,
Saturn V was used to launch
all the Apollo spacecraft on lunar missions.
The rocket alone
stood 110 metres (363 feet) high
and had three stages,
each of which fell away
when it ran out of fuel.
To follow what happened
as Saturn V took off,
start at the first stage:
• First Stage
The gigantic first stage
was the height of a 10-storey building,
and when filled with propellant,
it made up half the weight of the rocket.
Six furniture removal vans
would fit easily inside
its cavernous tanks.
These tanks fed fuel and oxidizer
to five F1 rocket engines.
The most powerful
rocket engines ever built,
they lifted the vast launcher
to a height of 61 kilometers
(38 miles) in just 2.5 minutes.
1. The first stage separated after 30 seconds,
when explosives blasted off the interstage ring.
Although it was the height of a house,
and traveling at 10,000 kph (6,000 mph),
the ring had to slip past the second stage engines
without touching them.
2. In an old-fashioned room heater,
paraffin burns with a cosy glow.
The motors of the first stage use this same fuel.
When mixed with pure oxygen, paraffin explodes,
producing enough power to lift
the 2,766 tone launch vehicle high into the air.
The intensity of the heat given off
would be enough to set fire
to a carpet 3 km (2 miles) away.
The Vehicle Assembly Building
The gigantic launch vehicle
makes NASA workers
look like ants by comparison.
They put together the rocket
inside a specially built hangar
called a Vehicle Assembly Building.
It was the largest building in the world
on its completion, and it is big enough
to enclose 3,700 family houses.
Weightlessness and fuel
In near-zero gravity conditions,
liquid fuel and oxidizer
float freely inside the tanks.
This means that vapour not liquid,
could flow to the engines,
stopping them from burning.
Firing small "ullage" rockets
prevented this from happening.
By accelerating Saturn V
for just a moment,
the ullage rockets pushed
the fuel and oxidizer
to the bottom of the tanks,
where the outlets were.
The engines could then fire safely.
The "Range Safety System"
consisted of explosive charges
to blow up the launcher
if it strayed from course,
thereby protecting the range (launch site)
and anyone in the path of the runaway rocket.
Despite the huge size of the launcher,
it was not heavy until the fuel tanks were full.
Ocean-going ships transported the launcher
to a dock near the launch site in Florida.
Some smaller sections even travelled
in specially modified aircraft.
The walls of each fuel tank had eight layers.
Fibre optics relay images
from lenses monitoring the engines
to TV cameras placed
a safe distance from the flames.
Electrical equipment and batteries
provided power for controlling the first stage,
and for measuring its performance.
For greater reliability
there were two complete sets:
if one failed, the other took over automatically.
To light the rocket motors engineers
pumped hypergol into the engine.
When this liquid comes into contact with air,
it bursts into flame, igniting the paraffin/oxigen mixture.
The power of the F1 engines
pressed the astronauts into their seats
with a force of 4.5 g (4.5 normal gravity).
Astronauts describe this as an "eyeballs in" g-force.
• Second Stage
When fuel ran out in the first stage,
explosives detached it,
and the five second-stage engines ignited.
They lifted the Saturn V launcher
and its payload -the Apollo spacecraft-
to an altitude of 184 km (114 miles).
1. The fuel and oxidizer
in the second-stage tanks
weighted as much three blue whales,
yet the tanks had no supporting structure inside.
They were built like an egg;
in proportion to their diameter,
the immensely strong walls
were as thin as eggshell.
2. The huge pipe that refueled
the second stage pumped
630 litres (138 gal) a second
-fast enough to fill the fuel tank of a car
in just a tenth of a second.
A "honeycomb" structure,
similar to the shape
of wax cells in a beehive,
made the walls of Saturn V extremely strong.
J2 rocket engines burned liquid hydrogen
and liquid oxygen at this second stage.
• Third stage
The third and smallest stage
of the Saturn V launcher
was the only to reach Earth orbit.
After circling the Earth once or twice,
the astronauts fired its engine
for the last time to blast
their craft towards the Moon.
Its work complete,
the discarded third stage
became just another piece of space junk.
Thermal tiles 37 mm (1,5 in) thick
kept the contents of the liquid oxygen
and hydrogen tanks ultra-cold.
The tiles were so effective
that if the ice had filled
one of these tanks,
it would have taken
twelve years
to reach room temperature.
The liquid hydrogen fuel
was stored at -252˚C (-423˚F).
Inside all the tanks
there were structures called baffles
to stop the contents from sloshing around.
A service tunnel carried power
and control cables along the exterior.
More than 2.5 million soldered joints linked these cables.
The third stage had just one J2 engine to provide power.
Manufacturers Rocketdyne test-fired the J2 engine
2,500 times on the ground to check
its reliability and to measure thrust.
Tiny auxiliary propulsion rockets
fine-tuned the spacecraft position in Earth's orbit.
Eight spheres contained high pressure gas,
which forced LOX into the engines.
An umbilical connector carried data
to the ground while the rocket
stood on its launch pad.
Technicians poured a methylated spirit
and water mixture into the coolant system.
This kept the delicate electronics from overheating.
Retro-rockets helped
separate the rocket stages
when the third stage motor fired.
Instrument unit
At the top of the third stage,
the Instrument Unit housed
the "brains" of Saturn V.
IBM computers steered the rocket motors,
ensuring that the spacecraft travelled into the correct orbit.
In case of breakdown, each computer
had three twin "sisters" which could take over.
Perhaps the most important instrument
was an inertial guidance system
- a gyroscope that sensed the slightest movement.
If the launch vehicle tilted slightly,
the inertial guidance system
would send instructions
to turn the rocket motors,
steering back to course.
Command Module
During the journey to the Moon,
the astronauts lived in the Command Module.
While two of them descended to the lunar surface,
the third stayed behind in the orbiting craft.
Building this capsule was perhaps
the most complex task of the Apollo programme:
it had over two million parts (a car has around of 2,000).
1. The pressurized crew compartment
was only a little larger than a compact car,
but in this small space the astronauts
had to eat, sleep, work, and keep clean for over a week.
2. Special shields surrounded the Command Module
to protect it from the intense heat generated
by re-entering the Earth's atmosphere
until it was 7,300 m (24,000 feet) above the ocean.
Then small "drogue" parachutes opened to slow the descent.
The main parachutes opened later,
slowing the craft enough to splash into the ocean safely.
Service Module
Fixed to the base of the Command Module,
the tubular Service Module carried supplies
of fuel and oxidizer, plus water and oxygen for the crew.
Its rocket motor moved the spacecraft into Moon orbit,
and powered it back to Earth.
Lunar Module
The Lunar Module
was the only part
of the Apollo 11 mission
to land on the moon.
On launch, the Lunar Module
was fixed below the Command
and Service Modules (CSM).
Once out of Earth's orbit,
the petal-like doors
protecting the Lunar Module fell away.
The crew then separated the CSM,
turned it upside down and linked up
with the exposed Lunar Module.
Finally springs separated
the Lunar Module from the third stage.
Building the Lunar Module
The Lunar Module was made up of two parts.
The descent stage took the craft
from the orbiting Command Module to the Moon
where it was left behind. Meanwhile,
the astronauts returned
to the Command Module in the ascent stage.
Descent stage
1. Construction of the descent stage
began with the aluminum frames
that supported the engine, fuel,
and oxidizers tanks.
2. A honeycomb material
filled the bug-like legs.
Touchdown crushed the honeycomb,
absorbing the force of the impact.
3. Technicians installed the pipework,
and wrapped the descent stage
in its "cooking-foil" blanket.
Ascent stage
1. The ascent stage was the "cab"
in which the crew would travel.
Engineers welded and bolted
it together from carefully
milled aluminium sub-assemblies.
2. When the ascent stage structure was complete,
assembly continued in a clean room, where
engineers installed life-support, propulsion,
and navigation sub-systems.
3. A thin aluminum skin covered
the protective thermal blanket
of the ascent stage to protect crew
and equipment from micrometeorites.
Assembly
When each stage was completed
the two were finally put together.
Lunar Rover
To enable astronauts to explore
a greater area of the Moon's surface,
three missions carried an electric buggy
called Lunar Roving Vehicle (LRV).
Its appearance and expense
caused some American politicians
to question "how three golf carts
could cost $40 million.
1. The Lunar Roving Vehicle's
three-piece chassis had to be light,
yet strong enough to transport
two astronauts, their equipments
and rock samples.
2. A navigation device pointed
the direct and distance to the Lunar module.
Such complex equipment raised the cost.
3. Manufacturers Boeing made special "tyres"
using mesh-covered piano wires.
These wire wheels provided a firm grip
on the thick dust of the moon's surface.
The wheels had outer rubber treads.
4. The Rover folded into a box
the size of a refrigerator
to stow away in the Lunar Module.
To unfold and assemble it
astronauts simply pulled a cord.
Space Suit
On the Moon, Extravehicular Mobility Units
(EMUs or space suits) protected astronauts
from the vacuum space, and from the heat,
cold, radiation, and meteors.
Each astronaut had three tailor-made EMUs:
one mission suit, one training suit, and one backup suit.
Apollo space suits had 21 layers.
Small tubes were sewn into the fabric of the underwear.
Technicians pasted a scratchy Velcro pad inside
each helmet because astronauts complained
that they couldn't scratch their noses.
Under their suits Apollo astronauts wore
nap pies but hated using them.
Special boots and gloves were locked to the suit.
1. The fabrics were high-tech but the construction
and expert workers sewed the seams.
2. The EMU was actually three garments:
liquid-cooled underwear, a pressurized suit,
and a protective cover.
3. To reduce sweating, cool water
circulated through small tubes running
through the all-in-one underwear.
Sweat was not only uncomfortable,
it also misted the helmet visor,
blocking vision.
4. Hoses at chest level carried oxygen
from the suit through
the Portable Life Support System (PLSS),
which filtered it to remove carbon dioxide,
flatulence, and moisture from sweat.
5. Each of the first five EMU cost $ 1 million.
They were constantly improved until
they allowed complete freedom
and were comfortable enough
to wear for up to seven hours.
Escape Tower
If the Saturn rocket
caught fire on the ground
or during launch,
motors in the escape tower
would ignite.
The tower would then carry
the Command Module
clear of the launch site,
and just high enough
for its parachutes to open
and slow its descent.
The rocket motor
had the power of 4,300 cars.
The crew crawled into the Lunar Module
through an access tunnel
The Lunar Module linked
up to the Command Module
at the docking ring.
Nearly 250 nylon strands
held the capsule
to the landing parachutes.
The heat shield
was made up
of seven different layers.
The filling in the honeycomb
structure of the walls
of the Command Module
cooled the craft.
The flight computer
had only 32 KB of memory
[La nada misma.]
Small jets were positioned
all around the spacecraft.
Controlling the firing of these rockets
enabled the astronauts to turn the craft.
Other: Antennae for transmitting
and receiving information
from mission control
Service Module Engine,
Engine nozzle, Drogue parachutes…
Saturn V
Apollo spacecraft:
Escape tower
Command Module
Service Module
Section housing Lunar Module
Instrument unit
Third stage
Interstage ring
Second stage
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