A rendering of Boeing's new Space-Based Space Surveillance Satellite. Credit: Boeing

With 20/20 hindsight, catastrophes can appear inevitable. The subprime mortgage meltdown. The BP oil spill. To avert a different kind of catastrophe, the U.S. military is trying to gain 20/20 foresight on the looming space junk crisis, which I wrote about in the June issue of WIRED.

To get an unprecedented view of the space waste cluttering the heavens, the U.S. Air Force is scrambling to reschedule the launch of the first-ever Space-Based Space Surveillance Satellite. Currently, the military monitors space junk through a ground-based network of radar and optical sensors. But this would be the first time that the Pentagon would capture detailed views of the 500,000 pieces of orbiting trash by relaying photos of debris from space itself.

The one-ton spacecraft will also keep watch on other spacecraft that might pose an accidental--or purposeful--menace to any of America's many vital satellites.

The launch, initially set for July 8, was delayed after tests found software bugs in the lift-off vehicle. The rocket is now expected to blast skyward in mid-August from California's Vandenberg Air Force Base, says a spokesman for Boeing, and the lead contractor on the project.

The new eye in the sky will start snapping photos at a time when the threat posed by space waste seems to be growing. In late May, the Pentagon released an alarming report to Congress warning about future collisions among active satellite and zombiesats--like last year's unprecedented crash between the long-retired Cosmos-2251 and Iridium-33. That smash-up added 2,000 fresh new fragments to a fast-growing catalog of debris objects. The Pentagon raised the specter that a catastrophic chain reaction of crashes has the potential to devastate the $250 billion satellite services industry, crippling global communication and commerce.

Then, in mid-June, NASA was alerted to three pieces of junk that zoomed dangerously close to the International Space Station during a docking mission. After a string of similar close calls last year, NASA officials have already called space junk the top threat to the $100 billion space laboratory and its international crew of astronauts. The ISS, flying at just 220 miles high, happens to inhabit the most cluttered band of low-Earth orbit (LEO).

Following that, President Obama released an 18-page National Space Policy that catapults the space junk problem to the very top of the space agenda. But in a break with the past, Obama not only called for more "mitigation" and monitoring of debris but also urged space junk removal, something that has yet to be tried. His 2011 budget for NASA is the first to propose funding for debris removal projects.

While the space debris situation is already perilous, the problem would be compounded if a collision between objects of different nations leads to a misunderstanding. After all, one man's waste can be seen as another man's anti-satellite weapon. What might at first appear to be an accident could develop into an international imbroglio.

"The center of gravity of American military power is in space," says George Friedman, the CEO of Stratfor, an Austin, Texas-based geopolitical consulting firm, in the new issue of Smithsonian. Looking ahead deeper into the 21^st century, he warns that an enemy who wants to attack the U.S. would strike first by knocking out our satellites, in order "to blind us, to cripple us."

That does sound ominous, and it's all the more reason to pay far more attention to a different kind of UFO, the unintended flying object.

Stephen Clark, over on Spaceflight Now reports that the doughty TDRS-1 communications satellite will be decomissioned and moved to a graveyard orbit this month after a legendary tour of duty. TDRS-1 was the first in a constellation of satellites that revolutionized America's ability to communicate with spacecraft in orbit.

Prior to the TDRS constellation, staying in continuous contact with, say, the space shuttle as it orbited the Earth required a daisy-chain of ground stations circling the globe, some of which had to be installed on ships parked in various oceans. The TDRS constellation allowed high-bandwidth signals to be relayed from anywhere in orbit, greatly reducing the number of ground stations needed, and eliminating the need for ships.

Launched from the cargo bay of the Challenger space shuttle in April 1983, a rocket engine failure nearly doomed TDRS-A.

Reducing the number of ground stations is not just a matter of convenience -- the Chinese human space program still relies on tracking ships, so launches of the Shenzhou spacecraft have been timed to occur during seasons of the year when the seas are likely to be calmest. Russia also relied on tracking ships, until the economic collapse of the Soviet Union resulted in the fleet being scrapped, with the result that mission control could only talk to cosmonauts onboard Mir for a few minutes every orbit.

Although it was never advertised, the biggest users of the TDRS constellation weren't NASA astronauts and scientists, but the military and the National Reconnaisance Office, who had priority use of the system for keeping in touch with their spy satellites. This occaisonally caused frustration for scientific users of the system, especially during tense geopolitical moments--in his book on the Hubble Space Telescope, The Hubble Wars, Eric Chaisson writes about the difficulty of scheduling telescope observations during the first Gulf War.

TDRS-1 had a difficult launch, and was almost a write-off when a failure in a transfer rocket engine left the satellite stranded in a elliptical orbit rather than its intended circular geosynchronous orbit. But over a period of two months, tiny thruster engines intended for attitude adjustments were used to nudge TDRS-1 into the correct orbit. In 1998, the satellite was retired from its original NASA and military communications mission and just used by the National Science Foundation to support polar researchers--notably being used to provide high-qulaity video conferencing during medical emergencies.

Now, the communications relay equipment onboard TDRS-1 has failed altogether, bringing the hardy satellite's saga to a close. The satellite will be moved out of geosynchronous orbit later this month prior to final disposal. This typically involves sending a satellite to burn up over some uninhabited part of the Earth to prevent it from becoming a hazard to other spacecraft.

TDRS-1's mission continues however, as the TDRS constellation has been upgraded over the years, with TDRS-10 being launched in 2002.

The European Space Agency (ESA) has announced that its newest satellite, called BepiColombo, will travel to Mercury using ion-electric thrusters developed by U.K. company QinetiQ.

An artist's impression of BepiColombo. Credit: ESA

The space agency already uses a smaller version of the same system--made of T5 ion thrusters--aboard its GOCE satellite, which launched earlier this year to measure Earth's gravitational field. BepiColombo, which is scheduled to launch in 2014, will use four T6 ion thrusters. The company says the thrusters used in both spacecraft are 10 times more efficient than traditional chemical ones. ESA awarded QinetiQ a contract worth $37.4 million to build the electric propulsion system.

While chemical propulsion systems are most commonly used in space, they are inefficient for deep-space missions to planets like Mercury because they require large amounts of fuel. Electric propulsion systems produce less thrust, but they are very efficient, making them ideal for long-distance missions.

Ion propulsion works by electrically charging, or ionizing, a gas and accelerating the resulting ions to propel a spacecraft. The concept was conceived more than 50 years ago, and the first spacecraft to use the technology was Deep Space 1(DS1) in 1998. Since then, aside from GOCE, there have only been a few other noncommercial spacecrafts that have used ion propulsion: NASA's Dawn mission to the outer solar system, launched in 2007; the Japanese deep-space asteroid-sample-return mission called Hayabusa, launched in 2003; and ESA's SMART-1 spacecraft, which launched in 2003 and crashed on the moon in 2006. (There are many commercial communication satellites that use ion thrusters.) NASA recently finished testing a new ion propulsion system for Earth-orbiting and interplanetary spacecraft that could be ready for launch by 2013.

While the technology still needs some fine-tuning, to make these engines even more efficient, compact, and economical, many experts say that for complex planetary missions that require lots of energy, ion-electric thrusters are definitely the answer.