SpaceX, the space company owned by billionaire Elon Musk, will launch this Wednesday (15th) the the company’s first mission with only civilians on board. If all goes as expected, this will be the world’s first fully civilian orbital flight.
Unlike flights from Virgin Galactic, of Richard Branson, and of the Blue Origin, from Jeff Bezos, both carried out in July with a few days apart, the spacecraft that will take the crew into space will reach an altitude of around 250,000 meters, which will make it remain in orbit — that is, keep circling around the Earth. While Branson reached the maximum altitude of 86 thousand meters, Bezos went a little further and came to be 97 thousand meters away from the Earth’s surface.
“There isn’t a very well defined boundary between the Earth’s atmosphere and space — from 100,000 meters above sea level, however, there is already a very small amount of atmospheric gases”, says astronomer Rodolfo Langhi, coordinator of the Astronomy Observatory at Unesp (Universidade Estadual Paulista). “It is possible to say, therefore, that from this altitude, the crew would already be in orbit.”
Professor Fabrício Colvero, creator of the Astronomical Chat project, explains that, for an object to enter the orbit of a star, it needs to reach a speed such that it neither returns to the star by gravitational action nor is sent into space. In the case of SpaceX’s flight, as the spacecraft will be at an altitude of around 250,000 meters, it will need to reach a speed of approximately 27,000 km/h.
Here’s how it works: the spacecraft ascends towards space, gains speed and, when it reaches 27,000 km/h, has its engines turned off and enters Earth’s orbit, in a trajectory parallel to the Earth’s surface.
The process is totally different — and much less safe — than that of suborbital flights, which are propelled like a shot upwards and return to virtually the same point, without being impacted by a collision with the atmosphere.
“In the case of suborbital flights, the biggest risk is actually the launch, since the rocket could explode during takeoff. In the case of orbital flights, the risks are of a different nature,” says Colvero.
“At the time of descent, the spacecraft enters the atmosphere at a speed of 27,000 km/h — the equivalent of 8 km/s — and, as a result, literally becomes a fireball. At that time, the atmospheric gases are already able to stop the speed of the vehicle, and when it reaches a certain altitude, parachutes are deployed to ensure that it lands safely in the sea,” he adds.
In addition to the risks, another difference between the two types of flight is that, in the case of orbital flight, the duration of the trip is much longer. For this reason, crew preparation also needs to be much longer, more intense and specific.
In the case of the SpaceX flight, the crew will spend three days in orbit, a period during which they will need to eat, go to the bathroom and attend to their physiological needs like anyone else. It is also worth mentioning that, despite the fact that the ship is piloted automatically, it is necessary for them to know how to take command of the ship in case something goes unforeseen.
“They go through different types of training, such as diving and walking on top of mountains, where the air is thin, so that the body is better prepared for the adverse situations of space travel,” says Colvero. Spending a few minutes in space, as Branson and Bezos did, is one thing; spending three days is quite another.”
*Intern of the R7 under the supervision of Pablo Marques