An increasing amount of space debris orbits the Earth. About 50 percent of all trackable objects are due to in-orbit explosion events or collision events. The debris objects shown in the images are an artist’s impression based on actual density data. However, the debris objects are shown at an exaggerated size to make them visible at the scale shown. Credit: ESA.
In 1996, the French satellite, Cerise, was hit by space junk. Credit: CNES.
Fire boat response crews battle the blazing remnants of the off-shore oil rig Deepwater Horizon. A RAND study on dealing with orbital debris flagged the Gulf of Mexico accident as an important lesson learned: Remedies must be designed and tested to work under actual operating conditions. Credit: U.S. Coast Guard.
All you need to do is look up into the nighttime sky. What you’re gazing at is fact: Outer space has become Earth’s largest junkyard.
The space environment has become a universal dumping ground. It is a “space-scape” of abandoned spacecraft and clutter generated by colliding satellites. Then there are the leftovers from roguish anti-satellite testing, depleted rocket stages, ejected lens caps and clamp bands, paint chips and, yes, at one point, even a lost-to-space tool bag. See Figure 1.
There are currently hundreds of thousands of debris objects greater than one centimeter in diameter in Earth’s orbit. Moreover, the collision of any one of these objects with an operational satellite would cause catastrophic failure or cripple that spacecraft. This swamp of orbital debris is a worrisome – and growing – problem, one that is ominous for the international family of Earth remote sensing satellite operators.
Take for example the February 2009 collision between a defunct Russian Cosmos spacecraft and a commercial Iridium satellite. That smash-up added to the number of bits and pieces already circling Earth. The unanticipated impact of the two satellites meant that the European Space Agency’s (ESA) radar-toting Earth Remote Sensing-2 (ERS-2) and Envisat missions were 30 percent more likely to face a catastrophic impact from space debris in the wake of the collision.
Two years earlier – compounding an already dire situation – was the purposeful demolition by China of its own inactive Fengyun-1C weather satellite. This January 2007 anti-satellite (ASAT) target practice by China created a debris cloud, a messy aftermath that has been spotlighted as the most prolific and serious fragmentation in the course of 50 years of space operations. Shrapnel from the Chinese ASAT test are likely to remain in Earth orbit for centuries, thereby complicating the ability of satellite operators to steer clear of on-orbit collisions. Indeed, that’s already been the case for NASA’s $1.3 billion Terra satellite. It has already been maneuvered to avoid a debris fragment.
In early 2010, a head-on collision was averted between a spent upper stage and ESA’s huge Envisat Earth remote-sensing spacecraft. A couple of tweaks of maneuvering propellant were used to nudge the large ESA spacecraft to a more comfortable miss distance.
In 1996, the French satellite Cerise was hit by space junk. See Figure 2.
The space debris environment for ESA’s remote sensing satellites has notably deteriorated following the Chinese ASAT test in 2007 and the collision of Iridium 33 and Cosmos 2251 in 2009, explains Heiner Klinkrad of the ESA Space Debris Office in Darmstadt, Germany.
“These two events contributed some 3,000 and 2,000 fragments, respectively, to the current catalog of the U.S. Space Surveillance Network. A large share of the fragment orbits are still in the vicinity of ESA’s ERS-2 and Envisat orbits. That led to a total of 9 avoidance maneuvers in the past year,” Klinkrad told Imaging Notes.
The untidy and unnatural implications from orbital debris are key agenda items addressed by the Secure World Foundation, dedicated to the secure and sustainable use of space for the benefit of Earth and all its peoples.
But understanding the space debris problem is one thing. Hammering out viable operational concepts to eliminate space rubbish is another. Then toss in legal and economic issues, as well as incentives. Add to this policy brew international policy and cooperation needs – it is clear that challenging work is ahead for all nations.
Late last year, a seminal report on orbital debris underscored possible ways to deal with the trouble – but moreso, it anchors thinking and approaches to more down-to-earth misery like handling hazardous waste, acid rain, ozone-depleting chlorofluorocarbons, and messy oil spills. The report, Confronting Space Debris - Strategies and Warnings from Comparable Examples Including Deepwater Horizon, was issued by RAND – the nonprofit think tank based in Santa Monica, California.
The authors identified a set of analogous problems that share similarities with orbital debris and narrowed this set down to the following nine issues: acid rain, U.S. commercial airline security, asbestos, chlorofluorocarbons, hazardous waste, oil spills, radon, email spam, and U.S. border control.
The ambition of the RAND appraisal is to provide context and insight for decision-makers by asking the following questions:
How have other industries approached their “orbital debris-like” risks?
What lessons can be learned from these cases before proceeding with debris mitigation or remediation measures?
Dead in the Water
In the RAND review, its findings were drawn from practical examples, one of which was the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. “Space and drilling underwater have a lot in common,” said Dave Baiocchi, co-author of the RAND report. “You can’t send a human to go do it…so you build some sort of robot. You’ve got one chance at it, so if your robot fails you’re dead in the water, literally,” he told Imaging Notes.
Baiocchi added that the Deepwater Horizon oil spill highlighted the issue that remedies must be designed and tested to work under the actual operating conditions. This is the biggest lesson from the Deepwater Horizon spill, he said, in that all of the remedies fielded during the first 40 days of the spill were not effective because they had not been tested or proven to work in deepwater drilling conditions.
Furthermore, the RAND assessment found that one remedy is not good enough. A remedy is often used to respond to an event that has already occurred. As a result, remediation technology is often very specialized. According to the study, several different techniques are necessary.
In the case of orbital debris, Baiocchi said it appears wise to begin developing a pathfinder system now so that alternative, tangential methods may be developed more quickly in the future. What’s more, on-orbit collisions are likely to continue to occur in the future.
When Push Comes to Shove
RAND co-author William Welser IV noted that, over the years, numbers of ideas to de-clutter space have been advocated: space tethers, laser beams, giant balls of foam, even some sort of robotic vacuum cleaner or garbage truck.
“But when push comes to shove…you better make sure that those things work in the environment that you need to have them work,” Welser said. It is important not to lull yourself into a false sense of security, he continued, with an untested tool box of possible solutions.
Late last year, a seminal report on orbital debris underscored possible ways to deal with the trouble – but moreso, it anchors thinking and approaches to more down-to-earth misery.
The RAND report waves a cautionary flag. That is, orbital debris, unfortunately, “belongs to the category of problems that are not easily observed either by those who create it or by those who might be harmed by it,” the study explains. “Because the harm is virtually invisible until a major collision occurs, the broader community may be simply unaware of the severity of the problem, or they may tend to underestimate the potential risk.”
Another RAND observation is that the Superfund program to clean up the nation’s uncontrolled hazardous waste sites could serve as a useful model for orbital debris cleanup. A “Superfund for Space” means that space polluters would be required to pay for clean-ups. It would create strong incentives for nation-states and private industry to take appropriate preventive steps to avoid creating more space debris.
“The fact is that there are so many players in space,” Baiocchi said, “and that’s rapidly changing,” with their report stressing that the entire space community needs to agree that purposely creating debris is not acceptable behavior.
“I’m optimistic,” Baiocchi concluded. “I started off thinking that this was an unsolvable problem. As you look to the comparable problems when they first were introduced (such as chlorofluorocarbons and ozone destruction to asbestos and hazardous waste disposal), they were overwhelming. But we’ve managed to get a handle on them.”
As for Welser, he too is confident about confronting the orbital debris dilemma. “We have a lot of smart people in the world that can work the technologies,” he concluded.