An illustration of the Naval Research Laboratory’s plan
to knock space junk out of orbit
Here on earth, green enthusiasts tend to judge people for littering, but for 50 years, we’ve had little opposition to cluttering up space. Today, there are hundreds of millions of objects in low-earth orbit, ranging from defunct satellites to trashed lens caps and frozen urine. More than just an aesthetic problem, space junk can crash into satellites and endanger ships passing through on their way to deeper space. Several plans have been proposed to clean up the mess, some requiring advanced materials like aerogels, but the latest suggestion is a bit more cost effective: It just requires a bit of dust.
What’s the News: The many bits of space junk orbiting Earth, from foil scraps to lens caps to chunks of frozen urine, can damage satellites and spacecraft, which is why researchers have long sought methods to remove debris from orbit. Scientists at the U.S. Naval Research Laboratory have proposed a new way of taking out the trash (in two senses): They want to pump 20 tons of tungsten dust into Earth’s orbit; this dust would exert drag on the junk’s orbit, slowing it down and gradually lowering it until Earth’s atmosphere can burn it up. This bid to protect Earth’s 900 active satellites is controversial because the dust could potentially harm solar panels on satellites and obstruct astronomical measurements, but it’s a handy fix because it doesn’t require ambitious new technology.
NanoSail-D, phone home.
On December 6, NASA launched its Fast, Affordable, Science and Technology Satellite (FASTSAT), which, among other cargo, carried the test craft NanoSail-D. No bigger than a breadbox, NanoSail-D was supposed to blast free from FASTSAT and spend three days floating free before spreading a 100-square-foot solar sail—what would be NASA’s first successful solar sail project. But while all signs initially indicated the 8-pound box succeeded in ejecting from the satellite, now NASA is not so sure. The agency is having trouble communicating with NanoSail-D, and its whereabouts are unknown.
“We have not been able to locate or make contact with NanoSail-D,” says Kim Newton of NASA’s Marshall Space Flight Center in Huntsville, Alabama. The sail was scheduled to unfurl on 9 December, but NASA reports that the deployment of the sail cannot be confirmed, and it is not clear whether the sail was successfully ejected into space. [New Scientist]
Yesterday, the Russian space agency Roscosmos confirmed news from last week that they are pursuing plans to spend $2 billion cleaning up space debris. In a striking contrast to the secrecy that once cloaked space programs, the confirmation came via an announcement on Roscosmos’s official Facebook page:
Russia will build a special orbital pod that would sweep up satellite debris from space around the Earth.The cleaning satellite would work on nuclear power and would be capable to work up to 15 years. Energia said in a statement that the company would complete the cleaning satellite assembly by 2020 and test the device no later than in 2023.
China successfully launched its second lunar probe on Friday, taking another step towards its goal of becoming a full-fledged space power. The probe, named Chang’e-2, made several maneuvers over the weekend to correct its trajectory, and is expected to reach the moon’s orbit this week.
The first Chang’e probe (they’re named after a Chinese moon goddess) orbited the moon for 16 months before self-destructing in a controlled impact with the lunar surface. This second craft is expected to return better data, because it will orbit closer to the surface than its predecessor and carries a higher resolution camera.
Chang’e-2 will orbit 100 kilometers above the moon’s surface and drop down to 15 kilometers on a mission to take detailed pictures of a candidate landing area for a follow-on craft, Chang’e-3, that is expected to be launched toward the end of 2014 or early 2015. [Science Insider]
The area of interest is known as the Bay of Rainbows, and the head of China’s lunar exploration program, Wu Weiren, says it’s the top choice for a landing spot.
For two years, the Chinese science satellite SJ-06F flew solo orbits around the Earth (or, as solo as a machine could be in the expanding haze of space junk in orbit). But now it has a partner: Last month China executed the delicate maneuver of aligning another satellite launched this year, SJ-12, with its older counterpart.
Only the United States had executed such a satellite rendezvous before this, and it shows off China’s advancement in satellite sophistication. Three years ago the country blew one of its satellites to smithereens in a practice test—a test that created thousands of additional chunks of debris in orbit. The satellite meet-up is a more elegant trick, and one whose implications could be sinister or benign. Let’s explore both possibilities.
China’s game of catch-up, which has its space program closing in on America’s abilities in orbit, strikes fear into the hearts of some politicos. But malfeasance need not be the aim of the satellite maneuver.
“This set of skills serves a whole lot of purposes,” says Dean Cheng, a Chinese policy expert with the Heritage Foundation, a think tank in Washington DC. The most immediate application, Cheng says, may be testing sensors and control systems to help pave the way for docking procedures to be used with China’s first space station module, Tiangong-1, which is set to launch in 2011. “This sort of thing may very well be consistent with wanting to test drive the hardware and software before you test it on your space laboratory,” Cheng says. [New Scientist]
Every time a space shuttle or the International Space Station has a near miss with a piece of space junk, we’re reminded just how much of the stuff litters the area around our planet—millions of total pieces amounting to more than 5,500 tons. The orbital debris includes everything from old rocket stages to shed paint flakes, and the situation worsened last year when two satellites collided, sending forth showers of debris. It’s a problem that grows steadily worse without an apparent solution, but now University of Surrey scientists say they’ve developed a possible solution: a tiny clean-up device with sails.
To help tidy up Earth’s orbit, the device could be attached to any piece of space-going technology. The CubeSail, which would measure more than 16 feet square when unfolded, is packed into a compartment that measures 4 inches wide and deep, and a foot long. When the sail is deployed, metal strips that are wound up inside the container straighten out and pull the sail flat. Despite its small size, the system could deorbit an object of up to 1,100 pounds, Surrey scientists say. CubeSail works by pulling against the small amounts of atmospheric gases present at orbital heights. Although the density of air molecules is low, it’s enough to make the sail act like a parachute, slowing it down, dragging the dead satellite to a fiery reentry much sooner than it would have done otherwise [Discovery News].
At 2:01 this afternoon in Florida, the space shuttle Atlantis is expected to roar off its launch pad and set off toward the orbiting Hubble Space Telescope, for the fifth and final repair mission in the telescope’s history. The countdown timeline is on target, and “Atlantis is ready to fly,” said Charlie Blackwell-Thompson, NASA’s test director…. The 11-day mission will include five spacewalks to refurbish Hubble with state-of-the-art science instruments. After the upgrades, the telescope’s capabilities will be expanded, and its lifetime extended through at least 2014 [CNN].
The current mission carries a higher degree of danger than the space shuttle‘s habitual jaunts to the International Space Station. Hubble orbits about 350 miles above Earth, in an area with a higher density of debris. Earlier this year two satellites collided over Siberia, which has increased the risk even more, as junk from that collision drifts lower [ABC News]. While NASA will track orbiting space junk as it always does, the agency has also taken the precaution of getting the space shuttle Endeavor ready for launch on another pad in case a rescue operation is necessary.
Astronauts flown up aboard the space shuttle Discovery are working hard to get the International Space Station ready for more residents: In May, the station’s live-aboard crew will expand from three to six members. But while some elements of the station upgrade have gone flawlessly, including the installation of the station’s final array of solar panels, astronauts encountered problems with other crucial procedures–like fixing the station’s urine recycling system.
The astronauts were given an extra task when NASA issued an alert about a piece of space junk that was expected to whiz past the space station at dangerously close range. With his ship still docked at the International Space Station, shuttle commander Lee Archambault fired up Discovery’s steering jets Sunday to move the linked craft into a new position that will reduce their chances of colliding with a piece of space junk [Los Angeles Times]. The four-inch chunk of debris, part of a spent Chinese satellite, is the latest reminder that orbital odds and ends pose a threat to the Space Station. Less than two weeks ago, crew members had to scramble into an escape pod as a precaution when another piece of debris came too close for comfort.
The International Space Station had a close shave this afternoon when a diminutive piece of space debris whizzed past the station at dangerously close range, forcing the first ever evacuation of the station. The three crew members took shelter in the attached Russian spacecraft that serves as an emergency lifeboat. The debris missed, and the astronauts quickly returned to the station after just 11 minutes aboard the Soyuz spacecraft. But the unusual event offered a reminder that astronauts and spacecraft are increasingly playing a deadly game of space-debris dodge ball in orbit [Washington Post].
The object that prompted the evacuation was a fragment of a motor used to launch a satellite. Although the piece of debris was only about one-third of an inch long, experts say that even tiny pieces of space junk can cause great damage, as objects in orbit travel at great speeds. Mission controllers detected the orbiting debris Wednesday night, too late for the crew to take evasive action, Humphries said. In previous instances, controllers have been able to maneuver the station out of the way of a threatening piece of space junk, “but because of the late notice, we didn’t have time to coordinate that,” he said [CNN].