Understand what suborbital flight is: lower flight cost, good for testing space flight technology

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Tencent technology news on July 20, with the first manned space flight by the founders of the space tourism companies virgin galaxy and blue origin, suborbital has become the focus of attention. So, what is suborbital flight? What’s the use of technology other than helping billionaires race into space?
On July 20 local time, Amazon founder and world’s richest man Jeff Bezos will take off on the new Shepard spacecraft built by his private space company Blue origin. It will be the company’s first manned space mission, reaching an altitude of 62 miles (100 kilometers), exceeding the recognized Carmen line. However, Bezos’s flight to the edge of space was nine days late for British billionaire Richard Branson, who reached an altitude of 53 miles (86 kilometers) on July 11 aboard a Virgin Galactic spacecraft.
Although both are impressive, they are very different from standard space rockets. Stephen mccandliss, Professor of astrophysics at Johns Hopkins University, said: “in short, the difference is that these suborbital flights do not have enough speed to go into space orbit.”
Space orbit means that the force generated by the lateral momentum of an aircraft or satellite can completely resist the gravity of the earth, so that it can travel along a curved path. Although it keeps falling towards the earth, it will never get close. When the orbiter is launched, it initially maintains a vertical upward trend, but when it passes through the thickest part of the atmosphere, it begins to tilt and increase its horizontal speed, so as to generate enough kinetic energy to stay in orbit.
However, in order to reach the space orbit, many arduous challenges need to be overcome. The vehicle needs to be kept in the horizontal orbit, and the speed depends on the altitude. To get into and stay in low earth orbit at an altitude of 150 miles (240 kilometers), the speed is about 17000 mph.
“In order to stay in orbit, you have to keep moving at nearly 8 kilometers per second,” McCandless explained. In addition, you have to reach a certain altitude and break through the atmosphere, and all this requires energy support. ” Any rocket that doesn’t have enough energy to reach orbit will follow a parabolic orbit, first up and then down, he said. Although such a suborbital space mission may be short-lived, passengers can still see an exciting view of the earth and experience weightlessness for a few minutes.
This is because the downward extension of orbit is essentially a free falling motion, and gravity acts on passengers and aircraft in the same way. Steven Collicott, Professor of Aeronautics at Purdue University, said: “the simplest explanation is that gravity pulls you down, and it also pulls the aircraft down, so you feel that there is no gravity locally. It’s a huge attraction for people looking for excitement. Blue origin and Virgin Galactic hope that this market can help them maintain a profitable space tourism business, but it also provides many interesting research opportunities. ”
Klicott said microgravity research has been carried out on the international space station for a long time, but experiments there are very expensive, and the equipment must withstand gravity and vibration to get into orbit. In contrast, suborbital flight costs less and puts much less pressure on equipment. “These travel vehicles make our journey to and from space more gentle,” he added. So tourism has created these very good, low-cost research laboratories for us. ”
In klicott’s view, suborbital flight is very useful for researchers to study phenomena that are usually covered by gravity effects, such as the settlement or condensation of solid particles in liquids. In his own work, he saw a lot of potential in suborbital flight, trying to understand the performance of liquids such as fuel or human blood in low gravity.
In addition, suborbital flight may be a cheaper way to test space flight technology or experiments, and then send them to orbit or deep space. For example, low gravity emergency surgery techniques can be tested, or all liquids in chemical or biological experiments can be ensured to stay in the right position after the transition from rocket assisted to zero gravity.
Short periods of weightlessness will be a limiting factor, but these suborbital flights also open up prospects for researchers’ experimental flights, klicott said. “It really opens up new areas of science where you can’t automate,” he added
However, McCandless said that these suborbital flights are not suitable for many space scientists. For the past 30 years, McCandless has been working with NASA to build exploration rockets or instrument borne rockets for scientific experiments in suborbital flight. Although these rockets are more expensive and can only be used once, they can reach an altitude of 435 miles (about 700 kilometers).
Such a height is necessary for all kinds of space physics experiments, including the study of ultraviolet astronomy by McCandless. Even at an altitude of 100 km, the atmosphere is dense enough to interfere with electromagnetic signals, so they need to remain above this altitude for a long time. “I’m going to tell people, ‘when you can reach 300 kilometers, come back and talk to me,'” McCandless said
Nevertheless, McCandless appreciates the efforts of private space companies to increase access to space, and believes that these companies are like early pioneers in ocean exploration or aviation. “Some people think it’s a waste, but I think it’s an evolution,” he said. Suborbital flight is essential if you want to have a more powerful infrastructure to serve space and deal with space problems. “( Tencent technology reviser / Jinlu)