Beyond the Karman line: how long does it take to get to space

Humanity has been flying into space for over 60 years, and since then, the debate about how long does it take to go to space has not subsided. Almost in any movie about space travel, there is a moment when a rocket takes off from the launch pad in puffs of fire and smoke, and, in a matter of seconds, we see how the picture in the window changes from the cloudy sky we all know to a peaceful blue-black expanse. There it is — space! But is everything as simple as they show in the movies? In one of our articles, we already asked ‘how long does it take to get to the Moon?’, so now, let’s find out how long to get to space.

How far is space from Earth? Оpinions are divided

The International Aeronautical Federation (FAI) officially considers space from the mark of 100 km or 62 miles above sea level. This hypothetical border is called the Kármán line, in honor of the American scientist Theodor von Kármán. He proved that at this altitude, the Earth’s atmosphere is sufficiently thin to make aviation useless. Aerodynamics and wings lose their meaning, since the aircraft speed necessary to create sufficient lift becomes greater than the orbital velocity of 7.91 km/s) and, therefore, to achieve greater heights, it is necessary to use astronautics.

The US Air Force has a different opinion. They hold that space flight begins at an altitude of 80 km or 50 miles. But during the Space Shuttle flights, the Mission Control Center in Houston marked the altitude of 122 km as the boundary of space. Why? This was the altitude at which the Shuttle began to experience atmospheric resistance during landing.

So who has it right? Presumably, FAI took the Kármán line as a standard, but in fact, there is still no physical or legally established boundary of space. How long it takes to get into space depends on the mission goals. The ultimate goal of most modern space flights is near-Earth orbits, Lagrange points, the Moon, or other planets of the solar system, which extend at an altitude of 200 km and above — all destinations requiring space velocities. That is why the Kármán line is still noted as the first frontier along that way.

How long did it take Jeff Bezos to get to space?

In July 2021, Blue Origin aerospace company founder Jeff Bezos and three others made the first-ever tourist space flight to an altitude of 107 km. The New Shepard spacecraft, flying along an elliptical trajectory, crossed the Kármán line after about 3.5 minutes, after which, under the influence of the Earth’s gravity, it headed back to Earth and parachuted to a landing. The entire flight took slightly over 10 minutes, three of which the astronauts spent in a state of weightlessness.

Does this mean that the Blue Origin crew went into space? Actually yes. The maximum speed of the New Shepard was 3,595 km/h, which was enough to pass the Karman line, but would not have been enough to reach low Earth orbit. That is why the New Shepard flight is considered suborbital.

How long does it take to get to space by different launch vehicles?

So, we’ve established any speed below the first space speed of 7.91 km/s is sufficient for the rocket to reach the Kármán line. This is quite enough for a suborbital flight, but for an orbital mission, the speed must be equal to or exceed 1 space velocity, and for interplanetary missions, 2 space velocity (11.2 km/s) will be required. This is the velocity required for a space vehicle to overcome the Earth’s gravity and leave the near-Earth orbit.

To perform a specific mission, the space flight system must have the appropriate performance envelope (engine thrust, launch weight, number of boost stages, etc.). They, in turn, determine the flight path and its time. To cross the Kármán line, it is usually enough to burn through the first and sometimes the second stages. The more powerful the engines, the easier and faster the ship will overcome the most difficult part of the journey — leaving the Earth’s atmosphere. After the 1st stage has burned all the fuel, it separates, and the 2nd stage is switched on. For example, a sufficiently powerful Space Shuttle with additional upper stages required two and a half minutes to reach the Kármán line. Let’s see how long it takes to get to space for modern rockets.

How fast can you get to space with modern rockets?

As you can see, it takes 3-4 minutes on average to pass the Kármán line. It takes another 5-7 minutes to reach a stable LEO (200 km). Of course, it all depends on the spacecraft and flight conditions, but to briefly answer the question of how long does it take to go to space, these numbers are quite enough. Now let’s look even higher.

How long does it take to get to the space station?

The International Space Station (ISS) is one of the main space travel destinations. Since its launch in 1998, manned and cargo vehicles have regularly arrived at it. Some crews that flew to the ISS were Space Shuttle (37 times), Progress (84), Soyuz (66), Dragon (32), Cygnus (18), and others. The total number of missions at the moment is 257.

How high is the ISS in miles?

ISS is in low Earth orbit at a distance of 420 km or 227 nautical miles from Earth. This is the average reading of the orbit point. The football pitch-sized station can be seen in the night sky as the third-brightest dot, moving like a plane but without flashing lights.

So how long does it take to get to the ISS? Typically, the time varies from 6 hours to 3 days, depending on the spacecraft type and mission profile. The Progress MS 17 spacecraft marked the speed record. On October 14, 2021, the manned mission reached the ISS in just 3 hours and 7 minutes.

How long will it take Space X to get to the space station?

SpaceX has been delivering cargo to the ISS since 2013. In 2020, the company conducted the first manned flight of the Crew Dragon with two astronauts on board, They reached the ISS in 19 hours. The 2021 Crew-3 mission for NASA was longer — 21 hours and 29 minutes. So, when the Crew-4 mission was in preparation, many wondered how long does it take to get to the International Space Station. On April 27, 2022, Crew Dragon delivered four astronauts to the ISS in 15 hours and 45 minutes after launch.

Bottom line

Humanity found the answer to the question of how long it takes to go to space, but is unlikely to agree on where space ends. After all, its scope is limitless, and today, even 60 years after the first space flight, we are still at the very beginning of this endless journey.