Friday, September 26, 2008

Where Do Satellites Go When They Die?


satellites earth

Images by: European Space Agency

No matter how often we hear about the developed world becoming more like Big Brother every day, it’s not until you see images that these from NASA that you get creeped out. How much are we being watched, traced, listened to, recorded? Anyone who has ever read George Orwell’s novel, 1984, might have seen it coming.

earth's saturn rings

The computer-generated image above was released by the European Space agency earlier this year, which shows the Earth looking more and more like our hula-hooping buddy, Saturn. The image highlights trackable objects orbiting the Earth; all 12,000 of them, and that’s just an estimation. Around 11,500, floating at an altitude of 800 to 1,500 kms, are thought to be military, scientific, commercial and navigational in nature but only around 7% are in working order. The rest are mostly telecommunications satellites and orbit in the direction of the Earth’s rotation, or geostationary orbit as it’s known. They sit about 35,786 kms high.

floating debris

Another image shows the differentiation between the satellites more clearly. Red depicts debris; the white dots are operating satellites and the outer ring is composed of satellites in geostationary orbit, which means they always sit of the same spot over the Earth.

North American Aerospace Defense Command (NORAD) has been tracking objects in orbit since 1961 but now there is real concern that, with so much material floating around up there, it may cause damage to existing satellites and, worse still, working astronauts. Even though much of the debris is too small to follow, their velocity can cause untold damage. Once a tiny speck of paint that had come loose from a satellite punched a quarter-inch hole in the window of a space shuttle! Imagine going all the way into space, carrying out your given mission and then succumbing to the wrath of a speck of paint. Nightmare.

close up of satellites

More of a worry though is not just what’s going to happen to the existing unwanted bits and bobs orbiting our planet but what about all the rest they’re planning to put up there? There’s a real danger of the space above our planet turning into the largest dumping ground in the ‘verse. And, what’s worse is, when all those aliens that people are expecting to visit to finally pop round for a chinwag, they’ll never be able to tell the difference between Earth and Saturn with all those rings.

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NASA’s Dirty Secret: Moon Dust

The surface of the Moon is covered in powdery gray dust that caused unforeseen problems for NASA astronauts. Apollo 17 astronaut Harrison "Jack" Schmitt took this picture of Eugene Cernan during their third and last walk on the lunar surface in December of 1972. (Credit: Courtesy of NASA)

The Apollo Moon missions of 1969-1972 all share a dirty secret. “The major issue the Apollo astronauts pointed out was dust, dust, dust,” says Professor Larry Taylor, Director of the Planetary Geosciences Institute at the University of Tennessee. Fine as flour and rough as sandpaper, Moon dust caused ‘lunar hay fever,’ problems with space suits, and dust storms in the crew cabin upon returning to space.

Taylor and other scientists will present their research on lunar dust at the “Living on a Dusty Moon” session on Thursday, 9 October 2008, at the Joint Meeting of the Geological Society of America (GSA), Soil Science Society of America (SSSA), American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and Gulf Coast Association of Geological Societies (GCAGS) in Houston, Texas, USA.* NASA will use these findings to plan a safer manned mission to the Moon in 2018. Taylor will also deliver a Pardee Keynote Session talk on Sunday, 5 October 2008 entitled “Formation and Evolution of Lunar Soil from An Apollo Perspective.”

The trouble with moon dust stems from the strange properties of lunar soil. The powdery grey dirt is formed by micrometeorite impacts which pulverize local rocks into fine particles. The energy from these collisions melts the dirt into vapor that cools and condenses on soil particles, coating them in a glassy shell.

These particles can wreak havoc on space suits and other equipment. During the Apollo 17 mission, for example, crewmembers Harrison “Jack” Schmitt and Gene Cernan had trouble moving their arms during moonwalks because dust had gummed up the joints. “The dust was so abrasive that it actually wore through three layers of Kevlar-like material on Jack’s boot,” Taylor says.

To make matters worse, lunar dust suffers from a terrible case of static cling. UV rays drive electrons out of lunar dust by day, while the solar wind bombards it with electrons by night. Cleaning the resulting charged particles with wet-wipes only makes them cling harder to camera lenses and helmet visors. Mian Abbas of the National Space Science and Technology Center in Huntsville, Alabama, will discuss electrostatic charging on the moon and how dust circulates in lunar skies.

Luckily, lunar dust is also susceptible to magnets. Tiny specks of metallic iron (Fe0) are embedded in each dust particle’s glassy shell. Taylor has designed a magnetic filter to pull dust from the air, as well as a “dust sucker” that uses magnets in place of a vacuum. He has also discovered that microwaves melt lunar soil in less time than it takes to boil a cup of tea. He envisions a vehicle that could microwave lunar surfaces into roads and landing pads as it drives, and a device to melt soil over lunar modules to provide insulation against space radiation. The heating process can also produce oxygen for breathing.

But the same specks of iron that could make moon dust manageable also pose a potential threat to human health, according to Bonnie Cooper at NASA’s Johnson Space Center. “Those tiny blebs of pure iron we see on the surface of lunar grains are likely to be released from the outside edges of the particle in the lungs and enter the bloodstream,” she says. Preliminary studies suggest that the inhalation of lunar dust may pose a health hazard, possibly including iron toxicity. Members of NASA’s Lunar Airborne Dust Toxicity Advisory Group, Cooper, Taylor, and colleagues are studying how moon dust affects the respiratory system. They plan to set a lunar dust exposure standard by 2010, in time for NASA engineers to design a safer and cleaner trip to the Moon.

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Chinese Say They're Building 'Impossible' Space Drive

By David Hambling

Chinese researchers claim they've confirmed the theory behind an "impossible" space drive, and are proceeding to build a demonstration version. If they're right, this might transform the economics of satellites, open up new possibilities for space exploration –- and give the Chinese a decisive military advantage in space.

To say that the "Emdrive" (short for "electromagnetic drive") concept is controversial would be an understatement. According to Roger Shawyer, the British scientist who developed the concept, the drive converts electrical energy into thrust via microwaves, without violating any laws of physics. Many researchers believe otherwise. An article about the Emdrive in New Scientist magazine drew a massive volley of criticism. Scientists not only argued that Shawyer's work was blatantly impossible, and that his reasoning was flawed. They also said the article should never have been published.

"It is well known that Roger Shawyer's 'electromagnetic relativity drive' violates the law of conservation of momentum, making it simply the latest in a long line of 'perpetuum mobiles' that have been proposed and disproved for centuries," wrote John Costella, an Australian physicist. "His analysis is rubbish and his 'drive' impossible."

Shawyer stands by his theoretical work. His company, Satellite Propulsion Research (SPR), has constructed demonstration engines, which he says produce thrust using a tapering resonant cavity filled with microwaves. He is adamant that this is not a perpetual motion machine, and does not violate the law of conservation of momentum because different reference frames apply to the drive and the waves within it. Shawyer's big challenge, he says, has been getting people who will actually look into his claims rather than simply dismissing them.

Such extravagant claims are usually associated with self-taught, backyard inventors claiming Einstein got it all wrong. But Shawyer is a scientist who has worked with radar and communication systems and was a program manager at European space company EADS Astrium; his work rests entirely on Einstein being right. The thrust is the result of a relativistic effect and would not occur under simple Newtonian physics. Many have dismissed his work out of hand, and British government funding has ceased. He has had some interest from both the United States and China. Now the Chinese connection with the Northwestern Polytechnical University (NPU) in Xi'an seems to have paid off.

"NPU started their research program in June 2007, under the supervision of Professor Yang Juan. They have independently developed a mathematical simulation which shows unequivocally that a net force can be produced from a simple resonant tapered cavity," Shawyer tells Danger Room. "The thrust levels predicted by this simulation are similar to those resulting from the SPR design software, and the SPR test results."

What's more, Shawyer says, NPU is "currently manufacturing" a "thruster" based on this theoretical work.

The NPU have confirmed that they have reproduced the theoretical work, and are building a demosntration version of the Emdrive.

Needless to say, independent confirmation is a big deal -- though many will want to see it published in a peer-reviewed journal. Even when it is, I doubt the controversy will subside. Prof. Yang has plenty of experience in this type of area, having previously done work on microwave plasma thrusters, which use a resonant cavity to accelerate a plasma jet for propulsion. While the theory behind the Emdrive is very different, the engineering principles of building the hardware are similar. The Chinese should be capable of determining whether the thruster really works or whether the apparent forces are caused by experimental errors.

The thrust produced is small, but significant. Shawyer compares a C-Band Emdrive with the existing NSTAR ion thruster used by NASA. The Emdrive produces 85 mN of thrust compared to 92 for the NSTAR (that's about one-third of an ounce), but the Emdrive only consumes a quarter of the amount of power and weighs less than 7 kilos, compared to over 30 kilos. The biggest difference is in propellant: NSTAR uses 10 grams per hour; the Emdrive uses none. As long as it has an electricity supply, the Emdrive will keep going.

The possibilities are phenomenal: Instead of going out of service when they run out of fuel, satellites would have greatly extended endurance and be able to move around at will. (We wouldn't have to shoot them down because of the risk from toxic fuel either.) Deep space probes could go further, faster –- and stop when they arrive. Shawyer calculates that a solar-powered Emdrive could take a manned mission to Mars in 41 days. Provided it works, of course.

What will China do with the technology? It may be relevant that professor Yang is not unknown in military circles, having published a paper called "Plasma Attack Against Low-Orbit Spy Satellites."

Meanwhile, what about the American interest? Shawyer told me that "the flight thruster program is on hold for the present. [O]nce the U.K. government had provided an export license for a U.S. military application, the major U.S. aerospace company we had been dealing with stopped talking to us. "

The company may have decided that the Emdrive could not work. If they're wrong, China has at least a year's head start in a technology that will dominate space and make previous satellites as obsolete as sailing ships in the age of steam.

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After River Pact's Backfire, McCain Counters Obama on Water

By Elizabeth Svoboda

Before weathering a storm of criticism over his willingness to renegotiate a major water conservation pact in the Southwest last month, Sen. John McCain toured the flood-ravaged town of Columbus Junction, Iowa, with its mayor in June. (Photograph by David Greedy/Getty Images

From offshore drilling (and Sarah Palin) to plug-in cars (and inflated tires), alternative energy has been the uncontested behemoth of environmental issues in the presidential campaign's homestretch. But when Sen. John McCain suggested renegotiating a key water conservation agreement last month, the ensuing political firestorm reminded voters just how important other "green" topics have become.

"I don't think there's any doubt the major, major issue is water and can be as important as oil," McCain told the Pueblo Chieftain after announcing his support for a rethink of the 1922 Colorado River Compact. "I think that there's a movement to ... adjust to the new realities of high growth, of greater demands on a scarcer resource."

Sen. Barack Obama fired back, hoping to court Colorado residents angered by McCain's implication that he would divert water resources from their state. "Opening the compact would pit the seven basin states against one another in extended negotiations, instead of facilitating cooperative efforts to address water supply challenges facing the arid west," read a statement posted on Obama's Web site. "I will respect the work the seven states have done and honor the Compact."

Scientific evidence leaves little doubt that America's fresh- and saltwater ecosystems are in dire need of protection: Recent studies indicate that climate change-induced droughts could threaten water supplies for up to 25 million Americans, and that global fish stocks could be wiped out by 2050. Meanwhile, a smorgasbord of assaults—Hurricanes Ike and Katrina not the least among them—have damaged miles of fragile Gulf Coast ecosystem. With help from analysts closely watching the preservation of water resources—and environmental advocates who were more inclined to be quoted for this article in PM's Geek the Vote series— we've unearthed the substance (or lack thereof) behind the candidates' promises.

Water Conservation

After McCain's call to renegotiate the Colorado River Compact provoked a backlash from some Colorado residents, he stood down. "Senator McCain has no interest in reopening the compact," McCain supporter Mitt Romney said the following week. "He believes as I do that a compact that's been worked out between the governors and the states is the right way to go." Some environmental analysts insist that McCain's backpedaling might foreshadow his unwillingness to enforce water-regulation measures while in office. "Rural western communities that have preferential access to water are one of McCain's key constituencies," says Glen Barry, founder of Ecological Internet, a popular non-profit aggregator for environmental analysis online. "He's hurt his political chances there by calling for a re-examination of the compact. If he's unable to raise the topic of water rights without fierce resistance from his supporters, that doesn't bode well."

While McCain has so far taken a state-by-state approach to the water management issue, Obama wants to take water conservation measures nationwide. He has voiced support for utility pricing structures that would make wasting water a more expensive proposition: "Prices and policies must be set in ways that give everyone a clear incentive to use water efficiently and avoid waste." Obama also supports funding federal programs that would teach farms and businesses how to switch to more efficient water-use practices. "Obama wants the federal government to be at the table," says Robert Lawrence, the director of Johns Hopkins University's Center for a Livable Future. "He or the Environmental Protection Agency would be in there to make sure the regulatory structure protects the shared water supply from corporate entities that may not have the people's best interests in mind."

Despite the new spotlight on water as a campaign issue, it can be tough to draw definite conclusions about the candidates' water stances if you go by their recent Senate voting records. In 2007, both Obama and McCain abstained from voting on the Water Resources Development Act, designed to provide funding for water conservation measures.

Fisheries Management

McCain, who cites conservationist Teddy Roosevelt as one of his heroes, has often spoken of the importance of preserving natural resources like fisheries. "We are vested with a sacred duty to be proper stewards of the resources upon which the quality of American life depends," reads a policy page on his Web site. McCain's platform is not particularly specific about how he intends to help U.S. fisheries become sustainable, however, other than to mention plans to get the fishermen themselves involved: "A vibrant hunting and angler community is essential to supporting our state and federal game and fish agencies."

When it comes to choosing between global fisheries management and U.S. self-determination, McCain has shown signs of favoring the latter. He has said he would vote against the United Nations Law of the Sea treaty, which includes international measures to ensure conservation of fish stocks and limits the exclusive fishing and economic zones that any one country can claim. "I'd like to make some changes to it," he wrote on a Web site last year. "I think we need a Law of the Sea. I think it's important, but I do worry a lot about American sovereignty aspects of it, so I would probably vote against it in its present form."

Obama, on the other hand, has expressed his unqualified support for the Law of the Sea, and Johns Hopkins's Lawrence predicts that this commitment will translate into a more active approach to fisheries management. "If we ratified the Law of the Sea, we would in fact yield some national sovereignty, but the law also has language about drift-netting and taking a more ecological approach to fishing," Lawrence says. "This is a big difference between the two candidates." Obama also advocates planning ahead on the fisheries front: He supports proposals to devote billions of dollars annually to state game and fish agencies to help ensure that fish and wildlife survive trends in climate change.

Coastal and Wetlands Conservation

In the years since Hurricane Katrina ravaged Louisiana's wetlands, McCain has expressed concern that America's "no net loss" wetlands policy is not being achieved. "Rapid urbanization and poor water resource management continues to claim a considerable acreage of our delicate wetlands," reads his online policy outline. "Therefore, we must develop policies that will protect these important natural assets for the benefit of all. This means employing long-term strategies that will preserve sensitive areas like the Everglades and the Louisiana coastal marshes."

Obama has also endorsed a "no net loss" policy for America's wetlands—the difference is he's been more forthcoming about how he intends to achieve this goal. His stated plan includes beefing up the so-called "swamp buster" provisions of the Farm Bill, which would decrease agricultural subsidies for farmers who attempt to develop wetlands, and updating the Clean Water Act to specify that it protects isolated wetlands. In 2004, as an Illinois state senator, he co-sponsored an act that provided for the conservation of wetlands within state borders.

The potential sticking point, environmental advocates say, isn't the candidates' rhetoric—it's that they seem likely to let other concerns, such as shoring up fossil-fuel supplies, stand in the way of their conservation promises. "McCain has clearly decided he's making a big deal about drilling offshore," says Rob Smith, the Sierra Club's southwest representative. "Louisiana has oil and gas under its marshes, and when you go in there to drill, you're bound to spill something. There's no such thing as a clean drill rig." Extensive drilling of the type McCain advocates could do significant damage to existing wetlands, advocates argue, and Obama also lost some wetlands-conservation credibility when he said he would reconsider his previous hard-and-fast stance against offshore drilling. "My interest is in making sure we've got the kind of comprehensive energy policy that can bring down gas prices," Obama told the Palm Beach Post last month. "What I will not do is support a plan that suggests this drilling is the answer to our energy problems."

Despite this recent reversal, Lawrence thinks imperiled wetlands would fare better under an Obama administration. "McCain has been very much ‘drill now, drill here.' Obama has also said we need to meet short-term energy needs with coastal drilling, but he's likely to be a little more environmentally sensitive."

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