Did you ever want to go to a place where almost no one has ever gone, and you say that money isn't a problem?
Well, look no farther because now tourists can go to space! There are different options for space tourism including suborbital flights, orbital fights and even a space hotel (i.e. let you fly in orbit, sub-orbit or even in a 12-day orbital hotel)!
The reason is that Boeing and SpaceX have a contract with NASA that allows them to bring a few extra tourists to space when astronauts are boarding or coming back from the ISS (International Space Station).
The space travel is exciting, but may not be as pleasant as you think. When you go into sub-orbit or orbit, your body will receive some G-forces, which is about 3.
This is survivable, but it is unpleasant. As 1 G-force is equal to the force of gravity on earth, 3 means you have to endure three times the force of gravity you normally live with.
When you are on an orbital or suborbital flight, you will have to pass the Karman line (100km above ground), this is where the atmosphere stops and space begins.
But to get to even the sub-orbit is very difficult because a suborbital rocket has to fly 6,000km per hour to achieve it. To get to orbit, it has to go a whopping 28,000km per hour. That is why orbital flights are tremendously hard.
The first time anybody ever went to space that wasn't an astronaut was a multimillionaire who paid 20 million dollars to board the ISS in 2001.
After that, six other tourists have gone to the famous ISS performed by the Russian space agency. These are the only tourists that have ever travelled to space so far, and then the Russian space agency stopped these operations in 2009.
Today, commercial operators are trying to promote space tourism. That's why Boeing and SpaceX could even have the contract with NASA to bring travellers to the ISS in the first place.
Right now, each suborbital flight takes about 15 minutes, and the two organizations that provide this kind of flyings are Virgin Galactic and Blue Origin, at a price of about 250,000 dollars per trip.
As to the space hotel, it is still under construction, but it made about 10 million dollars in pre-orders!
One thing that prevents us from space travel is money. The price is too costly that only multimillionaires can afford it.
But there is hope that, with the advance of technologies, the cost will be reduced substantially and one day it becomes as affordable as taking an airplane.
An example of technology reducing space travel costs is the Skyhook. A Skyhook is a tether hanging from the sky. It orbits around the earth and gives momentum to a spaceship or rocket when that spaceship catches the hook on it. This will reduce the size of spaceships by 84 - 96%. It is proven to be very efficient and helps reduce the cost of flying a spaceship.
Even though we already have some forms of space travel, it is only in orbits around the earth. There are so many planets for us to explore. There may be more types of space travel in the future, imagine that we can have a trip to Mars within hours, a long trip to another galaxy in a few days or launches from an ergosphere of a spinning black hole! How exciting it is!
suborbital “亚轨道”，亚轨道飞行不是通常意义的国际轨道和环绕地球飞行的太空漫游，而是刚刚脱离大气层进入太空边缘的飞行，让游客以较低的旅费进入真正的太空，体验失重状态的滋味，观赏黑色天空和地球弧线等美丽的外层空间景色.
the Karman line 国际航空联合会定义的大气层和太空的界线，高度为100公里。
太空的定义一般是以大气的性质，如密度为依据。但大气密度分布随高度是连续的，并没有明显的界限，因此没有很明确的定义。在FAI的定义中，没有明确的使用太空界限(edge of space)，而是用Karman line，指高度为100km（66miles）的界限，以Theodore von Kármán（冯 卡门）命名。
作文说话：
作者：大通，加拿大，五年级
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