Background information for Canada in SpaceBackground information for Canada in Space
Canada has accomplished some remarkable achievements in space technology. Below you will find a few subjects to investigate. You may also want to explore topics relating to our school program "Space: Space Exploration".
The payload is the cargo the rocket carries into space, (experiments, satellites, people). It is the reason for sending the rocket into space.
Since there is little oxygen in the upper atmosphere, the rocket must carry its propellants, fuel and oxidizer, with it. Propellants are a large portion of the weight of the rocket.
In liquid fuel rockets, fuel and oxidizer are pumped into the combustion chamber in the engine. This mixture is called a propellant. As the propellant burns, the exhaust gases are forced out of the nozzle at the back of the rocket, pushing the rocket forward (Newton's Third Law). Black Brants have solid fuel motors. The propellant is a rubbery mass of fuel and oxidizer. It burns along the axis of the rocket.
The Black Brant was named after a small, dark, fast flying Arctic goose.
Its purpose was to probe the
ionosphere, (the electrically charged upper atmosphere), from above, while instruments from the ground measured this atmospheric layer from below. The ionosphere, usually capable of reflecting radio waves, sometimes causes blackouts in radio transmissions, especially AM radio.
The orbit of the Alouette was circular, 1000 km above the Earth, inclined at 80o to the equator.
It was launched by NASA on a Thor-Agena rocket. This rocket carried a crossed flags insignia, symbolizing the joint venture.
It operated for a decade, and with it Canadian scientists became leaders in upper atmosphere research.
John Chapman was the head of the Alouette program. He became known as the architect of the early Canadian Space Programme, for this and subsequent pioneering projects.
The STEM was an antenna consisting of a flat strip of steel, about 10 centimetres across, wound on a reel. (Imagine a carpenter's metal spiral measuring tape.) This strip had been heat-treated, so that when it unwound, it snapped into a long tube, which was extremely strong. STEM stands for Storable, Tubular, Extendible Member.
STEMs were used on many of the early satellites and manned space capsules.
Alouette had four STEMs, two 22.5 metres long and two 11 metres long. (Two stems formed one antenna.)
STEM antennas were the first products of Spar Aerospace Limited of Canada, now a major developer and manufacturer of space hardware.
STEMs were used as booms or masts as well as antennas; one use was to push out the Hermes solar panels.
There are several examples in the Canada in Space: Destination Earth exhibit, at the Museum.
A satellite travelling in orbit around the Earth is actually falling, just like a thrown ball, towards Earth. If the Earth were flat, the satellite would hit the ground. But the Earth's surface curves away from the satellite, leaving it in free fall. If the satellite is going at the right speed for its height above the Earth, it never hits the ground, and is said to be "in orbit". Compare this to a ball on a string that is swung overhead: too slow a velocity and the ball will fall "out of orbit".
Most comsats use geostationary orbit, so that they stay above the same point on Earth. They make it possible to watch live transmissions of events like the Olympics. They link countries' telephone systems directly and cheaply. Much financial business is conducted at high speed via comsats, often in the form of computer data or pictures of documents. Comsats are also used to transmit educational material to remote areas.
