SPACE TOURISM BLASTS OFF, BUT TICKET PRICE IS SKY-HIGH
Flights by billionaires Branson and Bezos used two totally different technologies
With all the publicity surrounding Richard Branson's and Jeff Bezos' recent flights into space, you might get the impression that these men are the pioneers of space tourism. Actually, the honour of being the world's first space tourist belongs to American millionaire Dennis Tito, who, in 2001 paid $20 million for a ride to the International Space Station (ISS) aboard a Russian Soyuz rocket. An aeronautical engineer who once worked for NASA'S Jet Propulsion Laboratory, Tito made his fortune as an investment manager.
Tito had been captivated by Soviet cosmonaut Yuri Gagarin's orbital flight in 1961 and dreamt of following in his footsteps. He described his first sensation of weightlessness as the greatest moment of his life, and his ISS stint as “eight days of euphoria.” Seven other space tourists followed, paying the Russians millions of dollars until the program ended in 2009, when the U.S. Space Shuttle Program was retired, leaving the Russian Soyuz craft as the only means of transport to the ISS.
Space tourism was resuscitated on July 12, 2021, when Richard Branson, along with three crew members and two pilots, climbed into Spaceshiptwo, a winged plane with a single rocket motor that was attached to a specially constructed airplane. At a height of 15 km, the space plane was released, its engine ignited, propelling the vehicle to a height of about 80 km and allowing its occupants to experience a few minutes of weightlessness before landing 14 minutes later on a runway like a regular airplane.
There is a bit of controversy about whether the flight had actually been a “space flight,” since where space technically begins is somewhat contentious. Most regulatory agencies accept the “Karman line,” defined as 100 km above the Earth's mean sea level, as representing the boundary between space and our atmosphere. It is named after aerospace engineer Theodore von Karman, who was the first to make calculations about where the atmosphere actually peters out. Karman was born in Hungary, eventually becoming a professor at Aachen University in Germany, but because he was Jewish was forced to flee to America with the rise of Naziism. The U.S Armed Forces and NASA consider 80 km to be the demarcation of space, and by that measure, Branson and his crew are recognized as astronauts.
Spaceshiptwo is a descendant of the X-15 rocket planes of the 1950s and '60s. Carried aloft by a modified B-52 bomber, the X-15 would be detached before the single pilot ignited the rocket engine that burned anhydrous ammonia as fuel using liquid oxygen as the oxidizing agent. This reaction produces nitrogen and water vapour, gases that exit the engine with great velocity. According to Newton's third law that for every reaction there is an equal and opposite reaction, the plane is then propelled in the opposite direction. In 1963, an X-15 reached a height of 108 km and essentially became a spaceship. The pilot experienced a few minutes of weightlessness before hydrogen peroxide thrusters oriented the plane for re-entry into the atmosphere. Aerodynamic flaps, of course, do not work at that altitude because there is no air.
Richard Branson's flight was similar to that of the X-15, but Spaceshiptwo's engine burns hydroxyl-terminated polybutadiene (HTPB), a type of plastic, with the necessary oxygen being supplied by nitrous oxide, which at a high temperature decomposes to yield oxygen and nitrogen. Back in 1914, rocket pioneer Robert Goddard suggested the use of nitrous oxide, which was first made by Joseph Priestley in 1772 by the reaction between moist iron filings and nitric oxide. The latter was produced by dropping pieces of iron into nitric acid. Today, nitrous oxide is made by heating ammonium nitrate.
Priestley did not experiment further with what he called “nitrous air diminished,” leaving the next step in the development of the gas to the brilliant chemist Humphrey Davy. It was he who coined the term “laughing gas” upon noting its mirth-producing effects and also raised the possibility of its use as a pain killer. Laughing gas parties among the British upper class became quickly popular, but the painkilling effect was not capitalized upon until American dentist Horace Wells introduced nitrous oxide to dentistry in 1844. It is still used today to relax patients before undergoing dental procedures.
In the case of Jeff Bezos' flight on July 20, a totally different technology was in play. This time, there was no controversy about Bezos and his three mates having earned astronaut wings. The Newshepard rocket, named after America's first astronaut, boosted the crew capsule to an altitude of 107 km, clearly passing the Karman line. The launch was timed for the 52nd anniversary of NASA'S landing on the moon, and interestingly, the Newshepard rocket has similarities to the Saturn V that propelled Armstrong, Aldrin and Collins toward the moon, in that it uses liquid hydrogen as fuel and liquid oxygen as the oxidizer. The total flight took just about 11 minutes, with the capsule making a soft landing in the desert with the use of parachutes and retro rockets. Impressively, the booster also made a successful landing after having exhausted its fuel, ready to be used again.
The stage is now set for future space tourists, with Elon Musk's Space X rocket capable of orbital flight set to join the race. So, all aboard! Well, maybe not all. Deep pockets are needed for a ticket: $250,000 for a flight aboard Spaceshiptwo, and several million if you want to ride Bezos' Blue Origin rockets. Sky-rocketing costs, one might say.