NASA mourned the loss of its fallen astronauts this week, in a ceremony marking the 30th anniversary of the Space Shuttle Challenger disaster. It was complacency that contributed to that accident, something that has no place in the space business.

The space shuttles were promised as regular, low-cost access to space in a comfortable, shirt-sleeve environment — suitable for both professional astronauts as well as scientists, politicians, even journalists. 

This was to be done with reusable vehicles that take off like a rocket and glide back to Earth like an airplane, ready to fly again in a matter of weeks. With a fleet of five craft, the original idea was that a shuttle would be taking off several times a month, making spaceflight almost as easy as stepping onto an airliner.

The idea of a reusable spaceship made so much more sense than the previous era of gigantic Apollo moon rockets that were used once and then thrown away. It was the next logical giant leap into space.

Too bad it never delivered on those promises.

Even on the maiden voyage of Space Shuttle Columbia in 1981, the stresses of launch knocked insulating tiles off the shuttle body. When it returned to Earth, engineers found that the engines and many other parts had to be extensively re-built, making the turn-around time much longer than anticipated. This also increased the cost of flying.

NASA/

The Challenger crew takes a break during countdown training at NASA's Kennedy Space Center in this January 9, 1986. From left to right: Teacher-in-Space payload specialist Sharon Christa McAuliffe, payload specialist Gregory Jarvis, and astronauts Judith A. Resnik, mission specialist; Francis R. (Dick) Scobee, mission commander; Ronald E. McNair, mission specialist; Mike J. Smith, pilot; and Ellison S. Onizuka, mission specialist. (NASA/Reuters)

But the pressure to fulfil the promise of regular flights forced crews to work overtime to get the vehicles ready. More flights followed, more vehicles were added to the fleet, but the amount of work needed to turn them around after each flight kept adding to delays and escalating costs.

As the number of flights surpassed 24, space shuttle operations actually began to look routine, at least from the management point of view, and complacency began to settle in.

Sure, there were problems, but the program was proceeding, and that was good. In fact, shuttle launches were becoming so common that they often never made it onto the major news networks.

It was that complacency that led to bad decisions on the morning of Jan. 28, 1986.

Engineers had warned that cold temperatures would affect the reliability of rubber O-rings that sealed the segments of the solid rocket boosters. The rockets were assembled like giant coffee cans, stacked on top of one another, with the O-rings sealing them together. In temperatures below 11°C (53°F), the engineers said, the rubber would become hard and not provide a secure seal. The temperature that morning was barely above freezing at 2°C (36°F), the coldest launch day ever.

But the flight had already been delayed several times, and pressure was on to get the shuttle off the ground, so the warnings were ignored. Besides, this was Challenger's 10th trip to space and there had been no problems with its O-rings before, or on any of the other shuttles for that matter.

Space Shuttle Challenger 30th Anniversary Photo Gallery

In this Jan. 28, 1986 picture, the space shuttle Challenger lifts off from the Kennedy Space Center in Cape Canaveral, Fla. shortly before it exploded with a crew of seven aboard. (Thom Baur/AP)

When the O-ring seal did fail and hot gasses escaped, igniting the huge fuel tank in an explosive fury and killing all onboard, the shuttle program was placed on hold for three years, to fix both the technical problems and the way management decisions were made. But not all the problems were solved.

Complacency reared its ugly head again in 2003, when a piece of foam insulation punched a hole in the wing of Space Shuttle Columbia, allowing hot gases to penetrate during re-entry into the atmosphere, destroying the vehicle and taking another seven lives. Foam had been seen falling off on earlier flights, but was not considered a threat because no major damage had been done. Success breeds overconfidence.

The space shuttles were the most complex machines to ever fly. They delivered the material and people to build the International Space Station, launched and repaired the Hubble space telescope and brought hundreds of astronauts into space.

But by the time they were retired in 2011, each flight was costing more than $1 billion — hardly the low-cost mission that was promised. And losing two vehicles out of only five is not a very good safety record. (The 6th shuttle, Enterprise ,was only used for test flights and never flew to space).

As we enter a new era of private spaceflight, the lessons from Challenger and Columbia should remind us that complacency has no place in this business. Leaving the Earth is still extremely hard, even though we've been doing it now for more than half a century. It takes the absolute best technology, the sharpest minds, and most intelligent decisions to make it all work and bring the people home safely.  

That's also one of the best reasons to keep doing it.