Objectives

  • identify the challenges to manned space flight
  • describe the technologies used to meet the challenges to manned space flight

 

The first human being in space was Yuri Gagarin, aboard the Soviet ship Vostok 1, as he made one orbit around the Earth on April 12, 1961. This ignited the space race between the USA and the Soviet Union that led to the Apollo missions: man’s first landing on another celestial body.

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Rockets of varying sizes in Kennedy Space
Center's "Rocket" garden.


 

There have been several books written and films made about this period of time. It was an exciting sequence of events, as scientists experimented and tested the technologies to send human beings into an environment totally foreign to our experience here on Earth.



 

One of the first challenges to overcome was the lack of air. The vacuum of outer space provides no resources for breathing. A sealed compartment with a resource of compressed oxygen is a simple solution to this problem.

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Apollo 11 was the first manned mission to land on the Moon, in July of 1969. Pictured here
is astronaut Buzz Aldrin looking back towards the lunar landing module. Beside Aldrin is a
lunar seismometer that measures geological activity beneath the surface of the moon.


 

The next challenge was the cold of outer space. As mentioned in Module 6, Tutorial 1, the temperature of outer space is just under 3 degrees Kelvin, or -270?C. Insulation is needed and power available to heat space ships to keep human beings warm enough to survive. Having enough power for the heaters along with the instrumentation needed was a challenge in itself. But this raised another interesting problem – an astronaut in a fully insulated suit, and producing his own heat as well, will soon overheat. Modern space suits are equipped with both heating and cooling functions to keep astronauts at their most comfortable.



 

A third challenge concerns the radiation of outer space. Most of the radiation an astronaut will encounter is actually in the upper levels of our atmosphere, but there are still x-rays and UV rays radiating from the Sun. Heavy shielding is needed to block these harmful forms of light from irradiating the astronauts.



 

All of these technologies were available before the space race began, so the biggest problem was getting the equipment, along with the people, up into space. Vehicles needed to reach escape velocity to overcome the Earth’s gravity and become free floating in space. Therefore, the greatest test for the scientists was to meet all these challenges while still keeping the mass and size of the equipment and rocket to an absolute minimum, as well as maintaining safety.

 

Did You Know ?

The Saturn V rocket was one of the most impressive machines ever made. It was 110m tall, and 10m wide at the widest. It weighed 3,038,500kg, with 91% of this being fuel, and could carry a payload of 118,000kg. By the time it reached a low orbit it traveled at about 7900m/s, or 28,440 km/h, and it took just over 11 minutes to do this!


 

Captured German V-2 Rockets had been tested in the 1940’s to achieve sub-orbital heights, but something much larger was required to propel a large payload into space. The Soviets created the Vostok series of rockets shown below:

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The Vostok series of Soviet rockets. The smallest was a prototype to test the
general design, the middle rocket was the first to carry humans into space, while
the largest is a ‘Soyuz’ rocket which is still used to this day to launch satellites and
bring supplies to the International Space Station.


 

The Americans created the Saturn series of rockets, beginning with the Saturn I launched in October of 1961. The Saturn V rocket was the design that was eventually used to launch the Apollo mission to the Moon. They remain the largest rockets ever used. They were needed to be so large to not only lift the heavy payload out of Earth’s gravitational field, but also to propel them with enough speed to reach the Moon in due time. Although the Space Shuttle can carry a larger payload, the Saturn V was much more powerful, necessary because the Space Shuttle is not able to carry a payload to the Moon.

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The Saturn V rocket, popularly called the moonrocket, first flew as Apollo 4, shown
here, in November of 1967. It was very reliable with 11 successful launches and one
semi-successful launch in total. The only blemish occurred during the second test flight,
Apollo 6. This was an unmanned test that achieved orbit but not the desired perfectly circular
orbit. Apollo 13 also met with troubles on its mission but they were not due to the Saturn V.


 

These rockets all have multiple stages, which are parts of the rocket that contain engines and fuel which is burned off. When that part of the rocket is no longer needed, its mass is slowing down the rocket, so the stage is ejected and left to fall down to the Earth.

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These images show the individual sections of Stage I and Stage II of the Saturn V rocket,
respectively. Each stage is filled with fuel and ejected when the fuel runs out. The first stage
was ejected at an altitude of about 61km and fell into the ocean afterwards.


 

The next major development in manned space flight was the creation of the Space Shuttle. The Space Transportation System (STS), or ‘orbiter’ as NASA often refers to it, is designed as a multipurpose tool that can carry up to 11 astronauts, larger payloads and land itself upon re-entry. Instead of stages, the Space Shuttle uses individual rockets that separate as the ascent occurs. One of the most important features of the shuttle is its reusability. Each shuttle was originally designed to be useable for 100 missions, or 10 years.

 

Canadian Contributions

One of the areas in which Canada is a major contributor is the field of space robotics. The Canadarm is a large and multi-jointed arm located in the cargo bay of each space shuttle. It was first employed on the second shuttle mission and has been a mainstay ever since. It is necessary to manipulate satellites or other payload for deployment, stabilization, or retrieval in space. It is also equipped with a special sensor system to examine the outer shell of the shuttles for possible damage from lift-off. The Canadarm2 is a more complex version that is now attached to the International Space Station and has been instrumental in the station's construction.

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Mockup Canadarm in the shuttle's payload bay.





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Left - The Shuttle Atlantis during its first lift-off in November 1985. The two side solid
rocket boosters are fully ignited. These rockets expend their fuel and are ejected
at an altitude of about 46km. The central external tank is then used by the shuttle to
propel itself into orbit. The external tank is ejected at about 111km, and it is
designed to burn up in the atmosphere.
Right - Shuttle Atlantis at launch pad 39A in preparations for spring 2007 launch.


 

Initially, 5 shuttles built: Enterprise, Atlantis, Discovery, Columbia and Challenger. Enterprise was used only for testing purposes. Challenger was destroyed during launch in 1986, and the Shuttle Endeavour was built to replace it. Columbia was destroyed in 2003 during reentry. All of the shuttles are now well past their initial 10- year projected lifespan.



 

NASA has announced that they will retire the shuttles in 2010, replacing them with the new ship called the ‘Orion,’ which is designed to go beyond orbit. It will hopefully carry mankind to the Moon again, and perhaps even beyond that.

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The Orion spacescraft will be designed to return humans to the Moon. This artist’s
rendition shows the module circling the Moon with the Solar panels extended.


 

The Orion spacecraft actually incorporates multiple vehicles, some of which will remain in orbit until needed. This will include an Earth departure stage that will be put in orbit before the astronauts go up in the main Orion vehicle.



 

The last item to mention in discussing manned spaceflight is the space station. The Russian space station ‘Salyut,’ launched in 1971, was the first true space station in orbit. This was followed in 1973 by the American space station ‘Skylab,’ an orbital workshop for three people. Much later, the Soviets launched ‘Mir,’ meaning “peace” in Russian, in 1986. Their international collaboration of experiments and greater ability to support humans living in space (some cosmonauts remained in orbit for over a year!) paved the way for future space station systems. Now there is the multinational cooperative effort creating and maintaining the International Space Station (ISS).



 

Space stations are extremely important to space travel. Firstly, they allow sustained scientific research in space, enabling scientists to discover the long-term effects of humans living in space, the possibilities of growing plants in space, and many more necessary steps towards long space voyages. A space station also provides an important docking place for ships that are built for space. The most difficult part of a space mission is the takeoff and landing. Getting equipment up into orbit requires tremendous effort and money. The Orion spacecraft will be the first vehicle to take advantage of the possibility of staying in orbit for months at a time without having to return to Earth.



 

Eventually ships will be assembled in space around a space station and be more free to travel in the environment without the restraints of passing through an atmosphere. The ISS is already an example of this procedure. Its construction began in 1998, and now on each mission the shuttle delivers more materials to the station. Every so often it delivers a new section, such as laboratory facilities or additional crew quarters.

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The shuttle Atlantis delivered another solar panel to the ISS in September 2006. It is seen
here in the lower right, as photographed by the shuttle astronauts upon their departure.

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