My Science School

The space shuttle was the world’s first reusable spacecraft. Instead of a stack of rocket stages, it has separate booster rocket and a big fuel tank. The shuttle drops these before reaching orbit. It eventually glides back to Earth using its wings.

What is an MMU?

The Manned Manoeuvring Unit, or MMU, is a small strap-on spacecraft. Together with a space suit, the MMU lets an astronaut move freely through space. It uses 24 tiny jets of gas to travel in any direction.

Amazing! The shuttle has a special area for cargo. It can hold up to 29 tonnes. That’s the size and weight of an adult humpback whale!

Is it true? The shuttle is protected by tiles.

Yes. The shuttle is made from aluminium. This metal is very light, but it melts at high temperatures. A shuttle can heat up to 3,000oC as it returns to Earth, so it needs 20,000 heat proof tiles, which are glued on to its nose and belly.

What does the space shuttle do?

The shuttle was first used for taking large satellites into orbit. After one shuttle blew up in 1986, NASA decided to use unmanned rockets again for launching satellites. The shuttle is now devoted to research, repairing satellites in orbit, and to building a space station.

Robert Goddard, an American engineer, launched the first liquid fuel rocket in March 1926. His rocket, burning petrol and liquid oxygen, flew to a height of 12.5 meters and landed 56 meters from the launch pad. He showed that space flight might be possible in the future.

Amazing! The Chinese invented rockets around the beginning of the last millennium! Powered by an early version of gunpowder, Chinese rockets in AD 1000 looked like fireworks. They were used in battle as flaming arrows! For the last 1,000 years, most big advances in rocket design have been made as a result of war.

What did the first satellite do?

Sputnik 1 was launched into orbit by Soviet Russia on October 4th, 1957, 121 days ahead of its American rival, Explorer 1. Sputnik circled the Earth once every 90 minutes, sending radio messages for 21 days, which the world listened to on the radio.

Is it true? Rockets were used in World War 2.

Yes. The German scientist Wernher von Braun made rockets that could launch bombs across the English Channel. They damaged London without risking the lives of German pilots. Von Braun’s V2 rocket was so successful that after the war, American gave him a job helping with its space programme.

Who was the first earthling in space?

Before the first humans went to space, animals paved the way. Laika, a Russian mongrel dog, was the first earthling in space. Her seven days in orbit proved that space travel would be safe for humans.

Picture Credit : Google

Going by its name, it might be easy to guess where interstellar space exists – ‘Inter’ means in between, and ‘Stellar’ refers to stars. This would mean interstellar space is that part of space that exists between stars. However, that is not true.

Bye, bye heliosphere, hello interstellar

Interstellar space begins where the Sun’s constant flow of material and magnetic field stops affecting its surroundings. This place is called the heliopause.

The heliopause marks the end of the heliosphere, the region created by our Sun. the heliosphere, which is like a bubble, is created by the Sun sending a constant flow of particles and a magnetic field out into space at over 6,70,000 miles per hour. This stream of particles sent out by the Sun is called solar wind.

Like the wind on Earth, the solar wind pushes against any particles around it. This means the solar wind is constantly pushing against particles from other stars. The heliosphere exists till such a place where the solar wind can keep the foreign particles out. After this place, the interstellar space begins.

How do we know if we are in interstellar space?

Well, clearly defined boundaries for space are mentioned in paper, but it can’t really be seen with the naked eye. Interstellar space cannot be experienced on Earth. So far only probes sent by NASA have been able to identify interstellar space.

The probes would help us know we are in interstellar space when there is an increase in ‘cold’ particles around them. This is because, inside the heliosphere, the solar particles are hot but less concentrated. Outside the heliosphere, the particles are highly concentrated but are much colder.

The probes would also know they are in interstellar space when they identify a magnetic field that does not originate from our Sun.

Two probes sent by NASA – Voyager 1 and Voyager 2 – are the only ones to reach interstellar space.

 

Picture Credit : Google

You would have likely seen a lightning at one point of time or another. Did you know that the electrical discharges as a result of imbalances between storm clouds and the ground, or within the clouds themselves, is what is referred to as a lightning? These normally occur within clouds.

When a storm is occurring, the colliding particles of rain, ice or snow inside these storm clouds change the balance between the clouds and the ground. Whereas the lower reaches of the clouds often become negatively charged, the objects on the ground, including the Earth, become positively charged.

The resulting lightning passes current between the two charges and is nature’s way of normalizing the imbalance.

Lightning are extremely hot and it is this heat that causes the surrounding air to expand and vibrate in a rapid manner. This results in the thunder that we hear shortly after seeing a lightning flash. Lightnings are surely spectacular sights, but they are also deadly. There are thousands who die by lightning strikes every year, despite the fact that nearly nine out of 10 people who are hit by a lightning survive. The thousands of survivors are left with a variety of symptoms, ranging from memory loss and weakness to numbness.

 

Picture Credit : Google

Helicopters make good rescue aircraft because they can hover in the air and land in small spaces. At sea they hover while the crew pulls people from the water. They are also used to lift injured mountaineers to hospital.

Who invented the first true helicopter?

People had been making brief helicopter flights since 1907, but the first successful helicopter flight was in 1939. Inventor Igor, Sikorsky flew his VS-300, which had a single main rotor and a tail rotor. This was the ancestor of all modern helicopters.

Amazing! Helicopters can be used as cranes! ‘Skycranes’ can move heavy objects over short distances. They have a cargo space where the fuselage normally is.

Is it true? All helicopters have two rotors.

No. Very modern helicopters have a tail thruster, instead of a second rotor, but most helicopters do have two rotors. As the engine spins the main rotor one way, it also tries to spin the fuselage the other way. A second rotor on the tail stops this happening. On twin-rotor helicopters, the main rotors spin in opposite directions, so no tail rotor is needed.

What is an autogyro?

An autogyro has a rotor that is not driven by an engine. As the autogyro is pushed along by its propeller, the rotor spins round automatically, providing the lift that keeps the autogyro in the air.

The Harrier attack aircraft can take off and land vertically and also hover in the air. The exhaust from its jet engines comes out of four swivelling nozzles. For hovering, the nozzles point downwards. For forward flight, they point backwards.

Amazing! Engineers built a bizarre machine nicknamed the ‘Flying Bedstead’ to test vertical take-off and landing aircraft. It had two jet engines, and its real name was the Thrust Measuring Rig.

Which planes can take off and land in cities?

The de Havilland Dash flies between small airports with short runways that are often near city centres. The Dash can take off and land on a runway only a few hundred metres long.

Is it true? People can fly with jet-packs.

Yes. By strapping on the Bell rocket belt, a pilot could take off and hover in the air. At the beginning of the film Thunderball, James Bond escapes from his enemies with one. However the amount of fuel stored in the rocket belt limits the flying time to less than 30 seconds.

Which plane can swivel its engines?

The Bell/Boeing V-22 Osprey is part helicopter, part aeroplane. It has propellers or proprotors, which swivel upright for take-off, and it works like a helicopter. To go forwards, they swivel down and it flies like a plane.