Today, a number of con men are selling tickets for spaceflights to innocent people who are fairly rich and longing for adventure. Even reputable newspapers do not question the basis on which these offers and investments in facilities are made.

The space tourism vendors are selling impossible dreams of space flights for $20,000 or even $200,000 a ticket.

Let us be clear: These tickets concern flights into Earth orbit — not 20-minute jumps to high altitude, which is something else, and not, as some claim, a precursor to orbital spaceflight.

It is disheartening to see NASA, which knows better, participating in these games.

NASA Administrator Charles Bolden said: “It is my hope, it is my sincere hope, that a space tourism industry really takes off in the years ahead.”

But who knows, maybe they think they can persuade some congressmen to get bigger budgets.

Today, if you are clever, you could possibly negotiate an orbital flight with the Russians for around $20 million plus a few months of training, and of course assuming you are in good health. “Tourism,” though, has the connotation of something being available to many people.

But how many of us have $20 million to spare? There is no business in space tourism. This is due to basic laws of physics, so let us start with them.

Why is it expensive to go to space? Because the rockets needed are very big, complicated machines. To access space and remain in orbit, you must reach the so-called orbital speed, which is 28,000 kilometers per hour. Our civilian aircraft reach 1,000 kilometers per hour, and the best military aircraft maybe a little more than twice that.

How can one be propelled to orbital speed? Only by chemical rocket propulsion (Nuclear propulsion is politically unacceptable for the foreseeable future). In 1903, the Russian scientist KonstantinTsiolkovsky established the so-called rocket equation, which calculates the initial mass of a rocket needed to put a certain payload into orbit, given that the orbital speed is fixed at 28,000 kilometers per hour, and that the maximum speed of the gas exhausted from the rocket that propels it forward is also fixed.

You quickly find that the structure and the tanks needed to contain the fuel are so heavy that you will never be able to orbit a significant payload with a single-stage rocket. Thus, it is necessary to use several rocket stages that are dumped on the way up to get any net mass, i.e. payload, into orbit.

Let us look at the most successful rocket on the market — the European Ariane 5. Its start weight is 750 tons, of which 650 tons are fuel, 80 tons are structure and around 20 tons are left for low Earth orbit payload.

You can have a different number of stages, and you can look for minor improvements, but you can never get around the fact that you need big machines that are staged to reach orbital speed. Not much has happened in propulsion in a fundamental sense since Wernher von Braun’s Saturn rocket. And there is nothing on the horizon, if you discount controlling gravity or some exotic technology like that. In any case, it is not for tomorrow.

Space tourism requires that you not only get people up but you also get them back. That increases your difficulties considerably and increases your costs.

To come back, you need to reduce your orbital speed to a standstill on the ground. Coming back from orbit is as stressful as accelerating into orbit. You enter the upper atmosphere at the speed of a slow meteorite, and we have all seen the white-hot plasma surrounding the re-entering space shuttle. You have to be reasonably fit to sustain the deceleration.

Reusable systems have been studied extensively all over the world, and they are found to be horrendously expensive. (The full cost of a shuttle launch has been estimated to be $1.5 billion.) In studies of reusable systems, the payload has often been limited to around 10 tons in order to keep the vehicle to a reasonable size, not least for handling and operational reasons.

How many people could we launch at one time with 10 tons available? One must consider that they must have life-support equipment: toilets, oxygen, water, etc. Can we squeeze in 20 people? If so, the revenue is $400,000 with a ticket price of $20,000, or $4 million at $200,000.

Today, in the Western world, a big launcher costs around $200 million. Let us say we cut that cost in half to $100 million, or why not half again to $50 million. Even though the cost in this case has been reduced to an unrealistic level, it is still an order of magnitude more than the revenue from a flight.

You can play around with these figures, increasing the price or increasing the number of passengers in each flight, but you are still a long way from making price and cost meet.

Thus, even without adding all the difficulties of operating a reusable system, you don’t need to be a rocket scientist to understand that there can be no business case for space tourism. Most of the people who try to sell space tourism know this, but if you can sell a Ponzi scheme, why not space tourism?

Finally, a word on suborbital spaceflight. Here you accelerate as fast as you can, but you don’t reach orbital speed — far from it. You are shot up in the sky and you will feel the absence of gravity for some five minutes before re-entering the atmosphere. Here we talk about small vehicles, maybe for six people. Then $20,000 a ticket yields $120,000 in income per flight. Even disregarding safety issues, it is very difficult to show a business case. You can experience zero-gravity in an aircraft for a tenth of the price.

Suborbital hops are within present technology, but are there enough wealthy daredevils to sustain a commercial business? A single accident would severely disrupt the business, if not kill it altogether.

Some proponents of suborbital spaceflight will say that their device prepares for orbital space tourism. From the above it should be clear that doing a hop into space, suborbitally, is not a precursor to orbital flight and has nothing to do with reaching orbital speed and then decelerating to return to Earth.

To conclude, commercially balanced space tourism is neither for today, nor tomorrow, nor the day after tomorrow.

 

Fredrick Engstrom was the director of launchers at the European Space Agency (
ESA
) from 1994 to 2001; Heinz Pfeffer was the head of future launchers at
ESA
.