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Saturday, March 14, 2015

The Fastest Manned Plane Ever: North American X-15

Black rocket aircraft with stubby wings and short vertical stabilizers above and below tail unit in-flightWhile the Sr-71 Blackbird is considered to be the fastest manned plane of all time, it is actually only the fastest manned airbreathing jet plane to ever be mass-produced. The record for the fastest flying object every flown by a human goes to the X-15, an experimental plane which reached the edge of space and set altitude and speed records. This rocket powered aircraft reached a top speed of an amazing 7274 km/h or Mach 6.7. 13 of the X-15's flights actually went into space by going over 80000 metres, and the pilots immediately became astronauts. (Above right): An X-15 in flight.
The X-15 was based on a concept for a hypersonic research plane. North American Aviation and Reaction Motors were contracted to build the fuselage and engines respectively. The plane looks like an oversized missile with thick fins at the rear to provide stability during hypersonic flight, and indeed, it was launched just like a missile. Almost all of the X-planes were dropped from the bomb bay of a modified B-52 mother ship. (Right): An X-15 after being dropped.
Early X-15 variants used two Reaction Motors XLR11 liquid propellant rocket engines, which were then replaced by a single Reaction Motors XLR99 rocket engine capable of producing a massive 57000 pounds of thrust. It used anhydrous ammonia and liquid oxygen propellant, while hydrogen peroxide was used to drive the high-speed pump that pumped the fuel to the engine. (Left): A XLR99 on the tail of an X-15.
The X-15 was more like a space aircraft than a normal plane, and used rocket thrusters to steer unlike a normal plane which manoeuvres by altering the flow of air around its wings and tail. The reason for this method of manoeuvrability was that the air at the edge of space was too thin for normal mechanisms to work. Automatic systems controlled the rocket thrusters to keep the plane steady at high altitudes, although this could be overridden by the pilot. Pilots had to wear a spacesuit-like pressurized suit with an independent oxygen supply. Ejection was possible at speeds below Mach 4. (Above left): The cockpit of an X-15.
Although the X-15 was never mass-produced, the insights it gave into flight at hypersonic speeds at the edge of space were invaluable, and were used to further develop space planes and next-generation hypersonic spacecraft.

Saturday, March 7, 2015

Iconic Spacecraft: Saturn V

Image result for saturn v rocketThe Saturn V was, and remains to date, the tallest, heaviest and most powerful rocket ever built, and still holds the record for the heaviest payload ever taken to low Earth orbit, which weighed a massive 118000 kilograms. This was the rocket which was used to launch all the Apollo missions and was launched 13 times, with no accidents. It was a three-stage liquid-fuel rocket which was used for between 1966 and 1973 by NASA. It was also used to launch SkyLab, the first American space station. (Right): A Saturn V lifting off.
Image result for saturn v rocketThe Saturn V was the largest and most powerful production model of the Saturn family. It was developed by Werner von Braun and Arthur Rudolph at the Marshall Space Flight Centre. Several contractors were involved in the production of this massive rocket, some of them including Boeing, IBM, North American Aviation and Douglas Aircraft Company. The whole project had a budget of an amazing 6 billion dollars in 1964-73 dollars, which in today's money would be more than 40 billion dollars. (Left): A comparison of the Saturn V next to the Statue of Liberty and the Space Shuttle.
Image result for saturn v rocketThe Saturn V was the biggest and most powerful production launch vehicle every produced, and, with the Apollo Module on top, stood over 111 metres tall, which is 58 feet taller than the Statue of Liberty and 48 feet taller than Big Ben. In comparison, the Mercury-Redstone rocket used on the first American manned mission, was only 11 feet longer than the third section of the Saturn V, and delivered less thrust than the failsafe rocket on top of the Apollo Module. The Saturn V employed two new extremely powerful J-2 and F-1 rocket engines, which were so powerful that, when tested, broke the windows of nearby houses. (Left): The Saturn V being transported atop the crawler transporter.
The Saturn V was a three-stage rocket, as mentioned earlier. Each stage of the rocket took it to a higher altitude, and when it ran out of fuel, was discarded. The first stage of the Saturn V was built by Boeing, and weighed a massive 2200 tonnes fully loaded. Most of this weight was the liquid propellant which was used to complete the first 67 km of the rocket's journey. It consisted of five Rocketdyne F-1 rocket engines which would remain activated for the 168 seconds it would take the rocket to reach the 67 km mark. (Right): The first stage of the Saturn V being lifted into a vertical position.
The second stage was similar to the first in almost every way, although it had five J-2 engines, compared to the first stage's F-1 engines. It weighed over 408000 kg, with over 90% being the liquid hydrogen and oxygen required to fuel the massive rocket engines attached to it. (Left): The second stage of the Saturn V being lifted into position at the Mississippi Test Facility. 
The third and last stage had much less fuel than the other stages by weight, and consisted of only a single J-2 rocket engine which could be started twice. Fully loaded, this stage weight 119000 kg, with 19000 kg being the liquid fuel. The rocket engine was to be used twice during the mission in a 2.5 minute and 6 minute burst during flight respectively. Unlike the other two stages, which were transported by ship, the third stage was small enough to be transported by a large transport plane. The Instrument Unit, designed by IBM, sat on top of the third stage, and controlled all the aspects of the rocket from just before liftoff till the third stage was discarded. (Right): The Instrument Unit which sat upon the third stage.
The Saturn V was assembled at the Vehicle Assembly Building and transported to the launch site on the crawler transporter, a huge moving platform used by NASA to transport all manner of launch vehicles to the launch pad.
The Saturn V was, is, and probably will remain, the largest, heaviest and most powerful launch vehicle ever constructed.

Sunday, March 1, 2015

Iconic Spacecraft: Pioneer 10

Pioneer 10-11 spacecraft.jpg
Pioneer 10 was the first man-made probe to reach Jupiter and after that, the first probe to move out of the solar system. It is an American-made spacecraft and was the predecessor to the Pioneer 11 and the two Voyager probes. The project was conducted by the NASA Ames Research Institute and was built by TRW. IT was launched on March 3rd 1972 and took the first photographs of Jupiter on November 6th, 1973. During this period, over 500 pictures were taken and its instruments were used to study the asteroid belt, Jupiter's environment, cosmic rays, solar wind, etc. On January 23rd, 2003, radio contact with the probe was lost due to lack of electricity to power its radio transmitter. It was a whopping 12 billion kilometres away from Earth at that point. (Above left): A depiction of Pioneer 10 in deep space. (Above right): The launch of Pioneer 10.

The Pioneer 10 consists of a hexagonal bus that houses some propellant for orienting the probe towards the Earth and 8 of its 11 scientific instruments, which were housed in an aluminium honeycomb covered with mylar and kapton for heat resistance. Orientation was also checked by a star sensor and two Sun sensors. The Pioneer 10 carrier a plaque similar to those of the Voyagers which showed the position of Earth and what humans looked like, were it to be recovered by aliens. (Left): One of the photos of Jupiter taken by Pioneer 10.

The probe was powered by four SNAP-19 radioisotope generators which together provided 155 watts of power. The probe required 100 watts to power all of its systems, and over time, as the plutonium-238 inside the RSG's decayed, some of the system's were shut down to conserve power. (Right): Two of the 4 RTGs mounted on an extension boom.

Currently, the probe is about 106 AU from the Sun, and is travelling at around 26930 km/h. It is travelling 2.5 AU every year and it takes sunlight almost 15 hours to reach it right now. If it does not get intercepted by any celestial body, it will come close to the star Aldebaran and is heading towards the constellation Taurus.