Rockets have been launching people, robots and satellites into space for more than 50 years. But major failures still occur, highlighting just how hard it is to escape the bonds of Earth on a rocketship bound for orbit.
The year 2011 saw its share of launch and mission failures; thankfully, none of them involved astronauts. Here's a recap of the biggest space disappointments of the year:
The satellite was intended to provide three-dimensional maps of Earth for use by the Russian military. But a failure on the three-stage Rockot booster, which is derived from Russia's SS-19 intercontinental ballistic missile, left it stranded in orbit. Russian space officials managed to regain contact with the satellite to confirm its wrong orbit.
NEXT: A Wayward U.S. Missile
To be sure, the missile was not carrying an active warhead during the July 27 test, but a malfunction just after the weapon's launch from Vandenberg Air Force Base in California forced Air Force officials to destroy the missile using a remote destruct command.
NEXT: $300 Million Satellite Lost in Space
The satellite launched atop a Russian Proton rocket on Aug. 18, then promptly went silent. By mid-day on Aug. 19, U.S. space surveillance monitors found the satellite in the wrong orbit. One industry official said it would be difficult to maneuver Express-AM4 into operational position in geostationary orbit with sufficient life remaining to make the effort worthwhile.
NEXT: Air Force's Hypersonic Mystery
Another Air Force failure included a test launch of the X51-A Waverider, an unmanned hypersonic X-plane designed to test scramjet technology for ultra-fast vehicles.
The Waverider was air-launched over the Pacific Ocean on June 13 and reached nearly Mach 5 before failing to transition to its scramjet engine, which is designed to sustain flight at hypersonic speeds. Hypersonic flight is generally defined as any speed over Mach 5 (3,805 mph, or 6,124 kph, at sea level).
"Obviously we're disappointed and expected better results, but we are very pleased with the data collected on this flight," said Charlie Brink, the Air Force Research Laboratory's X-51A program manager, in a statement. The test was one of two planned for 2011.
NEXT: DARPA's Hypersonic Bomber Splash
The Falcon Hypersonic Technology Vehicle 2 (HTV-2) reached a speed of about Mach 20 (about 13,000 mph) before crashing. The flight was the second of two HTV-2 test flights and collected nine minutes of data, more than the first flight.
"Here's what we know," said Air Force Maj. Chris Schulz, DARPA HTV-2 program manager, in a statement. "We know how to boost the aircraft to near space. We know how to insert the aircraft into atmospheric hypersonic flight."
What happens next, though, is a mystery.
"We do not yet know how to achieve the desired control during the aerodynamic phase of flight," Schulz said. "It's vexing; I'm confident there is a solution. We have to find it."
NEXT: Blue Origin's Rocket Failure
According to Bezos, a "flight instability" drove an angle of attack that triggered the Blue Origin range safety team to terminate thrust on the vehicle. The vehicle roared skyward from the Blue Origin spaceport, located roughly 25 miles (40 kilometers) north of tiny Van Horn, Texas, before the failure.
"Not the outcome any of us wanted, but we're signed up for this to be hard, and the Blue Origin team is doing an outstanding job. We're already working on our next development vehicle," Bezos reported.
NEXT: NASA's Lost Glory Satellite
The failure occurred on March 4 during the launch of NASA's Glory satellite, a spacecraft designed to study the interaction between the sun's energy and Earth's atmosphere, with a specific focus on tiny particles – called aerosols – and their role in the planet's climate. But the Taurus XL rocket launching the satellite failed to jettison its nose cone fairing, and both the rocket and satellite crashed into the Pacific Ocean.
It was the second consecutive failure for the Taurus XL rocket. A similar nose-cone glitch doomed another NASA climate satellite in 2009.
NEXT: Chinese Satellite Lost
The failed rocket launch was the third in seven days for China, which promptly recovered from the malfunction to launch two unmanned space missions that demonstrated the country's first space docking – a major milestone for China's planned space station program.
NEXT: Russia's December Satellite Crash
"This area of the space industry is in sort of a crisis," Russian space agency chief Vladimir Popovin told reporters in a televised press conference today. "We can say even now that the problem lies in the engine." But more analysis is needed to be certain exactly what went wrong, he said.
NEXT: Iran Fails in Space Monkey Launch
The Iranian Space Agency reportedly attempted to launch a Rhesus monkey into space atop a Kavoshgar-5 rocket (Kavoshgar means "Explorer" in Farsi) during the Iranian month of Shahrivar, a period that ran between Aug. 23 and Sept. 22, according to an Agence-France Press report.
The setback was apparently a major blow to Iran's space ambitions, as the nation hopes to one day launch humans to space and, eventually, the moon.
NEXT: Russian Space Cargo Ship's Siberia Crash
The Soyuz rocket launched on Aug. 24, but its third-stage engine shut down unexpectedly, plunging the rocket and its attached Progress 44 cargo ship back to Earth. The vehicles crashed somewhere in Siberia.
A malfunction in a gas generator inside the third-stage rocket engine was later found to be the cause, and Russia resumed Soyuz rocket launches in the fall.
NEXT: Russian Mars Probe Falling From Space
After weeks of trying to salvage the spacecraft, Russian space officials said Phobos-Grunt had missed its window to depart for Mars. The spacecraft, which is also carrying China's first Mars orbiter, is expected to fall back to Earth by early January 2012. [Phobos-Grunt Mars Mission Photos]