Space agencies around the world, take note: The burgeoning private space industry isn't content to follow your lead.
At least three space tourism startups are building spacecraft that forgo the wing-and-parachute landing systems used by space shuttles and space capsules in favor of retrorockets. These rockets will slow down the new spacecraft enough to land gently on their feet, UFO-style.
The startups are betting that the technique will allow them to carry out missions more frequently and cheaply than NASA ever could.
"From a simplicity standpoint, there are less systems on there. There are no additional systems to land that you didn't already need to fly up," said John Carmack, founder of space tourism upstart Armadillo Aerospace, of his company's vehicle. "You basically just land it and fill it back up."
So-called soft landings aren't new to NASA or the Russian space agency. Both used the technique in the '60s and '70s to drop landers on the moon and Mars.
But when it comes to bringing astronauts home, the agencies have always preferred to take advantage of Earth's atmosphere to slow down their spacecraft -- hence, the wings and parachutes.
This saves them the expense of hauling around extra fuel for retrorockets. But it also means more complex vehicles that take longer to prepare before each launch.
Carmack, who is funding Armadillo Aerospace with the fortune he made developing the popular Doom and Quake video-game series, believes it's time to reconsider that philosophy. His company claims to have come up with a spacecraft design in which the extra fuel for retrorockets only adds roughly 10 percent to the vehicle's landing weight.
The trade-off is worth it, especially when you consider that designing wings amounts to "really a pretty nasty engineering item," he argues.
Parachutes are lighter but they come with challenges of their own.
"You have to design for large crumple zones. You have to repack the parachute (after) you recover it from what may be many, many miles away," he said. "The bottom line is that a parachute system can be lighter but you add a lot more difficulty to the turnaround."
Armadillo Aerospace has already performed 100 short takeoffs and landings with scaled-down test vehicles, according to Carmack. The company plans to show off an updated prototype at the X Prize Cup event in October.
Other companies developing soft landers include Norman, Oklahoma-based TGV Rockets and Seattle-based Blue Origin, founded by Amazon.com CEO Jeff Bezos.
TGV's spacecraft, dubbed the Michelle-B, will be 40 feet in length -- small enough to be transported in a truck. The company hopes to rent space on the vehicle to tourists and commercial users.
Blue Origin has been more tight-lipped about its plans. But the company released a brief description of its vehicle last week ahead of an environmental-assessment meeting required by the Federal Aviation Administration.
The description said that the vehicle will take off and land vertically from a 165,000-acre base in West Texas. It will carry three or more passengers and will operate without the help of ground controllers, relying on on-board computers to fly the spacecraft.
To be fair, none of the spacecraft under development are as complex as the space shuttle or the Soyuz capsule.
As suborbital vehicles designed for tourists and small payloads, they're not designed to go as high as their predecessors or dock to the International Space Station. That's one of the reasons why it's easier to perform soft landings in them, according to Neil Cheatwood, an aerospace engineer at NASA's Langley Research Center.
"With suborbital flight, the re-entry velocities are much lower," said Cheatwood. "You may not even need a heat shield."
The space shuttle, on the other hand, not only has to re-enter Earth's atmosphere, but it has to be able to fly to different landing sites, Cheatwood said.
That doesn't mean that NASA will never use the soft landing technique to bring astronauts back to Earth. In fact, the technique is under consideration for the vehicle that eventually replaces the space shuttle. The spacecraft, known as the Crew Exploration Vehicle, is slated to be ready by 2010.
Cheatwood conceded the soft landing option is not as popular as wings or parachutes for the CEV, but noted that it had not yet been ruled out.
"The ultimate landing system is still being considered," he said. "All those (options) are in the mix right now."
Ironically, the U.S. government had the most advanced soft lander program in the world in the mid-1990s. The Delta Clipper, or DC-X, was an experimental vehicle ordered by the Department of Defense but later handed over to NASA. In one test, it climbed to 8,200 feet and traveled downrange before turning back and landing near the launch site.
But an explosion after a landing in 1996 destroyed the vehicle and NASA did not have the budget to rebuild the spacecraft, so the program was canceled.
