The ISS is a huge artificial satellite orbiting the Earth at an altitude of about 420 km. To stay at the ISS for one or two weeks, these space tourists had to go through about a year of training, including astronaut-level programs. On the contrary, the space tourists of Virgin Galactic and Blue Origin could experience weightlessness for a few minutes at an altitude of 86 km and 107 km, respectively, after only a few days of simple training.

The program of Virgin Galactic and Blue Origin is a tourism flight that is completed through a continuous process, from launch to landing. Nevertheless, they're still called space tourism programs because they just reach the edge of space. Let's take a look at the two programs that offer space tourism for beginners at relatively reasonable costs.

The Virgin Galactic space plane launching from midair.

Virgin Galactic is an American spaceflight company founded by the famous adventurer and entrepreneur Richard Branson and his British Virgin Group in 2004. Virgin Group has many subsidiaries in various areas, including the Virgin Atlantic airline, the mobile carrier Virgin Mobile, and the Formula E team Envision Virgin Racing. One of these subsidiaries is Virgin Galactic, which was founded for space travel.

Branson is known to be an eccentric, but he knows how businesses are operated as a highly capable CEO, and he emphasized a practical goal from the beginning of Virgin Galactic. Instead of pointing at the moon and stars, he simply talked about flying high into the sky. Simply put, the primary goal of Virgin Galactic was to "taste space." It was a suborbital flight where they reach the Kármán Line, an altitude of 100 km called the edge of space, and experience weightlessness for about six minutes and land back.

Virgin Galactic adopted a spacecraft using air-launch where it is carried by a mothership and decouples in midair at an altitude of 15 km and fires its own engine to fly upward, instead of being launched from the ground. This is because they already have experience in operating airplanes through Virgin Atlantic. The "practical space travel" pursued by Branson is also not too expensive, comparatively. Air-launches have an advantage of lower cost compared to ground-launch since they require less rocket fuel and equipment.

Over the last 10 years, the mothership of Virgin Galactic has been upgraded from SpaceShipOne to SpaceShipTwo (SS2) and named VMS Eve. Eve is a large aircraft measuring 24 m in length and 43 m in width. Powered by four Pratt & Whitney turbofan jet engines (two on each wing), the aircraft features twin fuselage. It is launched by carrying a spaceship between its two fuselages.

According to the flight profile of Virgin Galactic, Eve decouples Unity at an altitude of 15 km, which is higher than the typical cruising altitude of civil aircraft. Immediately after separating from Eve, Unity fires its rocket engine and noses up to soar to space. During vertical acceleration, the direction of the thrust vector of Unity is also its nose. That’s why the passengers feel pushed toward the back of their seats, just like they do on a car or a plane. The difference, however, is the level of acceleration. The maximum acceleration of Unity is over 3G, and its maximum speed is over Mach 3.5. Once the acceleration is finished and its rocket is turned off, Unity folds its wings and reaches the peak with inertial navigation. This time, Unity reached an altitude of 86.1 km. Now it’s time to descend.

In fact, passengers start to feel weightless when the rocket engine is turned off before the plane reaches the peak. In this flight, the passengers could enjoy weightlessness for about four minutes. Once inertial navigation begins, the pilots tell the passengers to unstrap, then request them to sit and strap up before atmospheric re-entry. Unity begins to descend in feathering mode, then unfolds their wings at an altitude of about 21 km to glide.

Both Eve and Unity land on the runway of Spaceport America. Since this is a round trip, it is very convenient for not only the passengers, but also Virgin Galactic itself. Unity has landing gear like a typical aircraft, and has a nose skid instead of wheels at the front. Of course, the two rear wheels are fitted with typical airplane tires. The skid pad and rear wheels are stored in the fuselage and wings, and they only come out when the plane lands. From boarding to landing back, the Virgin Galactic space trip takes only less than two hours. When counted from the moment when Unity separates from Eve, it is just 10 minutes.

Immediately after the successful pilot flight on July 11, Virgin Galactic announced it would start space tourism with paying passengers from next year after it completes some additional tests this year. The price starts from 450,000 dollars per person, and the company plans to provide a 2-person or family plan, as well as full-occupancy 6-person plan.

The New Shepard of Blue Origin, featuring a typical vertical takeoff.

Blue Origin is an American aerospace company founded in 2000 with the macroscopic, future-oriented vision of “expanding humanity” and “moving the industries that stress the Earth into space.” The most interesting fact is that Blue Origin was founded by Amazon founder Jeff Bezos. Officially, it is a limited liability corporation but everyone regards it as a personal company owned by Bezos..

Every person wants to realize their dream. Space is one of the top items in the “wishlist of humanity.” To realize their dream, many people study astronomy, seek to become air force pilots, and try to enter an aerospace agency or company. And when it comes to Bezos, he simply set up a company. He develops rockets and spacecrafts at his own expense. That is the power of the richest man in the world.

According to economic magazine Fortune, Bezos has spent at least 5.5 billion dollars for Blue Origin so far. Space Capital, a space venture capital fund, estimated it as 7.5 billion dollars. Nobody knows the exact amount. Unlike Virgin Galactic listed on the NYSE, Blue Origin doesn’t need to disclose its financial statements. Bezos is also not a big talker, and hasn’t disclosed these figures himself. With so much information remaining confidential, we sometimes hear news like, “Bezos will sell his Amazon shares worth 1 billion dollars to invest in Blue Origin.”

Blue Origin also set its first business goal as suborbital space tourism. Its journey of reaching the Kármán line at an altitude of 100 km and landing back is not that different from that of Virgin Galactic, but the Blue Origin spacecraft takes off from the ground, just like a typical vertical-launch “rocket.” It also resembles a typical spaceship such as Apollo and Soyuz. Its rocket, however, sets it apart from the spacecrafts we’re familiar with. After completing its mission as a launch vehicle to carry a spaceship to space, it comes back and gently lands on a separate landing ground. Aiming to make access to space cheaper, Blue Origin also considered reusable launch vehicles from the beginning.

The New Shepard rocket plays the leading role in Blue Origin’s suborbital space tourism. It is equipped with one BE-3 engine with 50 tons of thrust and uses liquid oxygen and liquid hydrogen. Atop the cylindrical rocket is a passenger capsule. The capsule is 3.6 m in diameter and features 15 ㎥ of space. It also boasts the “largest-ever windows in a spaceship,” one for each of the total six seats. As the capsule reaches the Kármán line and descends only with a trajectory flight, these seats are all occupied with passengers without pilots.

The cylinder in the center of the capsule is the Crew Escape System. It is a rocket designed to quickly pull the capsule to a safe distance from the launch vehicle in the event of any problem with the risk of explosion of New Shepard after takeoff. The spire-like structure at the top of Apollo also played the same role. There is no particular structure except the seats and the escape system in the capsule, which allows for a tall and large space. The space is large enough to unbuckle their 5-point seat belts and float around once the capsule enters the weightlessness section. The outer top of the capsule is equipped with a parachute that opens when landing.

Last May, Bezos announced that the first manned space flight of Blue Origin would take place on July 20. This is the day on which Neil Armstrong from Apollo 11 took his first step on the moon in 1969. The four passengers are Jeff Bezos and his younger brother Mark, Wally Funk at 82, and Oliver Daemen at 18. Funk is one of the "13 female Mercury astronauts" who passed their tests at NASA in the 1960s, but could not fly to space due to her gender. Daemen, the first paying passenger, is a son of a businessman who won the space travel ticket at Blue Origin's charity auction program. Funk and Daemen also earned the title of oldest and youngest astronaut respectively.

On July 20, the New Shepard was set up at Launch Site One, the Blue Origin’s dedicated launch site located in western Texas. Just like the Apollo crew did 50 years ago, the passengers including Bezos boarded the capsule through the gantry connected horizontally to the platform, and it took a tediously long time to complete final inspections, just like for the Apollo. After all the preparations were done, the New Shepard was finally launched. Nothing was too different from a typical rocket launch that we would watch from news shows.

The maximum acceleration of New Shepard is over 3G, and its maximum speed is over Mach 3. The rocket turns off its engine at an altitude of about 75 km and starts to descend. The separated capsule passes the Kármán line and reaches an altitude of 107 km with inertial navigation. The Blue Origin passengers can enjoy weightlessness for about four minutes, learning how dark it is beyond the atmosphere and appreciating the beautiful Earth through the big windows.

The remaining steps of the flight are free fall and landing. The capsule that re-entered the atmosphere descends slower than when it ascended due to air resistance, and it opens up its parachute at an altitude of 3 km. Meanwhile, the rocket is also falling down toward the ground and starts to decelerate with its air brake on the top at an altitude with sufficient atmosphere. The rocket heads down to the landing site about 3 km away from the launch site, and fires its engine again at an altitude of 2 km to reduce its speed. It makes a precise landing by opening its landing gear. The landing speed is about 8 km per hour. About three minutes from then, the capsule lands at 1.6 km per hour on a desert about 20 km away from the launch site.

Same purpose but different form?

As mentioned earlier, both Blue Origin and Virgin Galactic offer a suborbital space tourism product that reaches just the Kármán line. The share the same destination and the same itinerary of "touch and return," without stay. But their capsules look totally different from each other. Why is that?

It’s because they adopted totally different takeoff and landing methodologies. The New Shepard of Blue Origin adopted a vertical launch rocket and a passenger capsule mounted on top of the rocket. In the history of space development, this form factor has been tested and proven, leading to the formulaic “cylindrical launch vehicle and conical payload.” The representative case is the command module of Apollo. Boeing’s CST-100 Starliner manned spacecraft, which is currently in development, is also a conical type.

A spacecraft does not necessarily have to be a conical type. There is also a bell type, similar to a cone, and the Soyuz descent module is a good example of this. Another bell type spacecraft is the Dragon, the orbital spacecraft of private aerospace company SpaceX, which transports cargo and astronauts to the ISS. The New Shepard of Blue Origin is also a bell type. These spacecrafts take this form partly because of ascending and partly because of re-entry.

First, it considered the air resistance and shock wave it would get while ascending on the high-speed rocket. To endure gravity and get into orbit, it must fly at more than 25,000 km per hour. Now, imagine that the rocket has a box or cylinder at its top. To exceed 300 km per hour, you need something more like a hyper car, rather than a truck.

Re-entry means the process of re-entering the Earth's atmosphere. While re-entering the atmosphere as fast as it escapes from the atmosphere, the spacecraft cannot control its posture and is exposed to tremendous compressed heat exceeding 2,000℃ in the air. Areas with some equipment such as windows, hatches, docking devices, antennas, and parachute port are relatively vulnerable to heat and impact. A spacecraft that has heat-resistant tiles with its center of gravity at the bottom of the cone can fall naturally balanced and protect its vulnerable parts.

Re-entry means the process of re-entering the Earth's atmosphere. While re-entering the atmosphere as fast as it escapes from the atmosphere, the spacecraft cannot control its posture and is exposed to tremendous compressed heat exceeding 2,000℃ in the air. Areas with some equipment such as windows, hatches, docking devices, antennas, and parachute port are relatively vulnerable to heat and impact. A spacecraft that has heat-resistant tiles with its center of gravity at the bottom of the cone can fall naturally balanced and protect its vulnerable parts.

Unlike a typical spacecraft that re-enters the atmosphere from the Earth’s orbit at Mach 25, New Shepard reaches only an altitude of 107 km and falls with a trajectory flight. So, it has an initial speed of 0 and does not exceed the velocity of sound during its free fall. High heat is not a concern, but we still need to consider the passengers. What if the spacecraft is shaking or even overturns while falling? To fall safely while maintaining its vertical posture, even before opening its parachute, the spacecraft should have a conical or bell shape whose center of gravity is located at the bottom.

On the contrary, the VSS Unity of Virgin Galactic also has the form of an airplane for two reasons. First, Unity adopted the air launch method where it is carried by its mothership at take-off and separates from the mothership in midair, then fires its own engine. Imagine the Apollo spacecraft, instead of Unity, is attached between the fuselages of the VMS Eve. Do we have to set it upright? Or make an inverted triangle with its larger bottom facing up? Or do we have to place the apex of the cone horizontally with the direction of travel? You just can’t find a solution. That’s why it’s reasonable to adopt an aeronautical design in this case.

More importantly, Unity glides and lands horizontally when it returns from weightlessness while traveling. Instead of descending vertically, it glides without power like a glider and lands on the runway. This is the method adopted by American space shuttles. That is also why Unity has wings and landing gear like a space shuttle. A spacecraft with aeronautical properties is called a spaceplane.

Virgin Galactic and Blue Origin were founded with different backgrounds. It is interesting that despite having the same purpose of visiting the edge of space, the two firms have adopted different journeys and methodologies. Maybe these differences will be what make their space tourism products more attractive. At any rate, if I do travel to space, I'll have choices. Of course, I will have to open an installment savings account before that.