Commercial space exploration and tourism were dealt a major double punch in the last two days.

First an Antares rocket by Orbital Science Corporation exploded at lift-off. It was an unmanned rocket with a payload destined for the International Space Station, contracted by NASA. The rocket and payload were worth $200 million, and there was additional damage to the launch pad.

Then, yesterday, there was a catastrophic failure of Space Ship Two, the Virgin Galactic vehicle designed to take tourists into space starting in 2015. In this case, the catastrophe occurred during a high altitude test flight. Two pilots were on board, one died, and the other is seriously injured. No details have been released. I am actually amazed that one pilot could have survived such an explosion. I am sure we will find out the details eventually.

Already there are voices claiming that the private sector does not have enough of the Right Stuff to be successful in space, and that we might want to leave space exploration to the expertise of NASA, or the Russians, or the Chinese, or the Indians. David B. Grinberg’s column here is such an example.

Have we really forgotten the famous “O-ring disaster” that destroyed the Space Shuttle Challenger in 1986? What about the heat shield failure in the Columbia catastrophe. What about the Apollo 1 fire on the launch pad?

The fact is, space travel and space exploration are very serious and very dangerous endeavors. With the technology we have today, to reach orbit, a space vehicle consists of more than 85% propellant when it sits on the launch pad. 85% is on the low side, as it was the case for the Space Shuttle. When a rocket with a capsule is launched, it’s more like 95%.

To visualize that, picture an aluminum can of Coca Cola. It contains 94% Coke and 6% packaging. A rocket, in comparison, usually has about 95% propellant and 5% packaging. A rocket is therefore more flimsy than a soda can. But it’s not benign soda that’s inside the package. In the case of the Space Shuttle external tank, it contains cryogenic fluids at 20 degrees above absolute zero (0 Kelvin), pressurized to 60 pounds per square inch and can withstand 3gs while pumping out propellant at 1.5 metric tons per second. On top of that, we put little capsules with tiny, soft and fragile human beings that need a constant temperature of 98.6 degrees F.

Space travel is dangerous. Rich and famous people like Justin Bieber, Ashton Kutcher, Leonardo DiCaprio and Stephen Hawking have signed up for $250,000 per flight on Virgin Galactic. Many will fly, and inevitably, some will die along the way, even though the risk with suborbital space travel, like it is in the case of Virgin Galactic, is far, far lower than it is with orbital flights.

This was a hard week for the space community. It was a formidable setback. But I am rooting for Branson and Musk and the many other visionaries who are building effective solutions that advance the human race and provide alternative ways for us soft and fleshy things to get off this planet.