Why space shuttles take off only Vertically. But Airplanes take off Horizontally?
rocket with space shuttle
The view of a rust-colored rocket carrying an orbiter on
it’s back, spewing giant clouds of smoke and rushing to the sky on its fiery tail
is iconic.
But considering the last Space Shuttle launch was back in
2011, is this the last we’ll ever see of such a thing? What’s next?
Could an improved shuttle be made
that takes off and lands like an airplane?
Let’s explore the possibilities.
Explanation with an Example.
Use your imagination to draw two parallel horizontal lines.
Now connect these lines at any point you want, in two different ways:
with a vertical line that goes straight from the bottom
line to the top one,
and with a diagonal line. Which line is shorter? Of
course, the vertical one; it’s the shortest route to connect the top and bottom
lines with each other.
And that’s also the most basic answer to our question –
it’s faster and easier to get into orbit by just going
straight up from the ground. The bottom line is the Earth’s surface. Our
planet is a complex hodge-podge of allkinds of matter, which is combined
into an impressive mass – almost 6
sextillion tons; that’s like 6,000 billion of billions - a lot of zeros here –
just like my middle School math scores.
All that mass basically works like a colossal magnet that,
besides other significant feats, allows the Earth to maintain one thing we all
know and love – the atmosphere.
Factor of Atmosphere.
where do space shuttles fly in the
atmosphere
The top line is the limit of the Earth’s atmosphere;
anything beyond that is the planetary orbit and outer space. But the atmosphere
itself is also filled with matter. It’s
a combination of gas that has its own density.
When a shuttle launched, all the mass of this gas was
constantly pushing on it, which caused friction, effectively slowing it down.
Going through a vacuum is like cutting through the air, whereas getting through
the atmosphere is like going through jelly. Ooh, grape or strawberry? It took a
lot of energy and force to get through it, while being pulled back by that
giant gravitational magnet called Earth.
Flying Principle of Airplanes.
Airplanes don’t struggle this much with getting through the
atmosphere, because they use its density to lift up from the ground and
maintain altitude. Two things help them
with that: the thrust of their engines and the form of their wings. The
wings of an airplane force the air in front of them to split into two streams.
Naturally, these streams want to reunite behind the wing,
but the shape of it makes the upper stream go faster. The faster the air goes,
the less dense it becomes; and that means that the airstream that goes
underneath the wing is denser than the upper one. That creates a gradual lift
for the airplane.
How Airplanes achives speed.
Basically, wings make it so the airplane can glide on the
air. But of course, that wouldn’t be possible without a huge force pushing the
airplane along. This is what thrust is for. Just to take off from the ground,
an airplane needs to attain a huge speed. This speed varies enormously between
different kinds of planes:
60 mph for light planes, and about 150 mph for airliners.
And, just to take off and climb to 10,000ft, the Boeing 747 needs a little less
than 3 tons of fuel. That may sound impressive, but let’s look at that space
shuttle. The first obvious things are the cute, tiny, stubby wings that
wouldn’t be any use for a horizontal take off.
But if one was built
with more excessive wings, they wouldn’t be of any use in the vacuum of space.
It would also be hard to make them sturdy enough to make it through the
launching process. The little wings of a space shuttle served only one purpose
– to land the shuttle safely so it could be reused in future missions. They
were just big enough to prevent the shuttle from spinning uncontrollably during
the descent through the atmosphere, and to glide it to the ground.
How Airplane lands?
It didn’t utilize any engine operations during landing at
all. The engines of the space shuttle were nothing like the engines of a plane.
The airplanes’ engines need air from the atmosphere to work. The shuttle’s
engines obviously didn’t, since atmospheric air would’ve been hard to find in
space.
Instead, the shuttle used rocket engines. To show what
rocket means here, and how these engines worked: just blow a balloon and
release it from your hand. It’ll fly around until there’s no air left inside,
all the while being pushed in the opposite direction as the air coming out.
To fly up, a rocket engine has to throw off enough thrust,
and burn the right amount of fuel to do the job. In fact, space shuttles needed
so much fuel during their ascent, to make enough thrust, that they couldn’t do
it on it’s three engines alone.
They needed two additional solid rocket boosters and a huge
separate fuel tank that was jettisoned at the final stage of the launch. And, a
shuttle would only go into orbit if it had enough power. The power of a shuttle
with three engines and two boosters is around 7.8 million pounds of thrust!
To power up this much push, an external tank held around 1.6 million pounds
of rocket fuel. And to keep the flight under control, those three engines
had to be mind-numbingly complicated in structure. But would it even be
possible to fly a shuttle into orbit if it was modified to use the atmosphere
like planes? Unfortunately, the answer is no. It would take even more fuel to
maintain the needed speed for the distance of a diagonal launching trajectory.
Explanation.
The thing is, even if a plane climbs up to the upper part of
the atmosphere, the Earth still won’t let it get away. To escape the
atmosphere, any object that starts from the Earth would have to be fast enough
to cross the point of so-called escape velocity. This velocity is needed to
overpower the gravitational pull of the planet and let an object go into orbit.
For our planet, this orbital speed is 17,500 mph. It’s obviously way faster than
the speed of sound and many, many times faster than the cruising speed of an
airliner. Now try to imagine an aircraft that goes this fast, and how much fuel
it would require. On top of that, it’d have to be sturdy enough to keep itself
in one piece while doing so.
The cost and complicated technology would just be
unrealistic. The possibility that shuttles have become a thing of the past has
caused Scientists and engineers alike to try to find even better solutions for
getting into orbit and beyond. One such idea proposes that in the future, people
would be able to go to space on a huge space elevator. A space elevator is the
concept of a huge tower that connects to a satellite at the top, which moves in
line with the rotational movement of the Earth itself. The tower is supposed to
be about 22,000 miles high and made of extremely durable material – carbon
nanotubes. The platform inside the tower is planned to be set in motion via
electro-magnetic powered vehicles. The trip from Earth to the satellite would take
just 5 hours.
This megastructure would allow for a cheaper and safer way
of getting into space, but carbon nanotubes were proved not sturdy enough for building
a tower this huge, so the search for an ideal material continues. Another
project that uses a similar approach his called a Space Tram. The structure
needed to launch this project isn’t as big, but still quite impressive. It’s a
vertical vacuum tunnel that pushes a magnetically levitated shuttle. It won’t
be slowed down by the air, and it’ll be pushed and accelerated with an
electro-magnetic force through the tunnel. It’ll then shoot into the skies at a
speed close to escape velocity. The shuttle powered by this tunnel will weigh less,
because it won’t need to carry a lot of fuel. NO word yet on how human beings
would survive such acceleration. Riders might look like pancakes upon arrival.
If these ideas sound
strange to you, and they do, then get ready for the last one. It’s possible
that people will use planes as a way of getting into orbit. No, I didn’t lie to
you previously. The plane won’t go to space by itself. Instead, it’ll be used
as a launch platform. Even better, huh? For this purpose, a special aircraft will
be made with an almost 400 ft wingspan, and capable of climbing to an altitude
of 35,000ft. Small shuttles launched from this aircraft won’t have to go
through so much of the atmosphere, making it easier for them to get out from
the gravitational pull of the Earth. Richard Branson is working on this
technique right now with his Virgin Galactic program to take tourists to the
edge of space. Sounds esciting! So could airplanes replace space shuttles altogether?
No, but that doesn’t mean they won’t help them become more effective in the
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