Five myths about the satellite smash-up. Operation was messier than it seemed

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MSNBCFive myths about the satellite smash-up How perilous? How precise? Operation was messier thanit seemedBy James ObergNBC News space analystupdated 4:39 p.m. ET, Wed., Feb. 27, 2008Last week's Pentagon operation to bring down a fallingspy satellite may have been widely termed a"shootdown" of precision accuracy - but the reality ismore complex, and much messier.As military officials take stock of the event'sphysical and political fallout, it's worth dispellingsome of the misconceptions and myths that couldotherwise cloud the thinking of policymakers and thepublic during the debate over past and future"shootdowns."Myth No. 1: The Navy missile shot down the satellite.Reality: Hitting a satellite with a missile is not atall like hitting a bird with a bullet and watching itplummet to the ground. An orbiting satellite stays inorbit not because of its power or guidance, but merelybecause of its forward speed. An attack that does notsubstantially change that orbital velocity cannotdrive the satellite out of orbit, no matter how muchphysical damage it does.The only practical way to remove such targets fromorbit is by slowing them down. In practice, thatoccurs as a result of air drag, an effect that cantake hours, weeks, or centuries depending on thethickness of the air at the satellite's altitude.Breaking a big spacecraft into smaller pieces doesincrease the effects of air drag - as demonstrateddramatically last week - but it is the key role of airdrag that makes the critical causal link between"shooting" and "downing" the target.Myth No. 2: Falling satellites aren't reallyhazardous, and since they've never hurt anybodybefore, they were unlikely to hurt anybody this time.Hence, there must have been a secret "real reason" forthe missile mission.Reality: First, counting on a string of successfullydodging bullets is no open-ended guarantee of beingbullet-proof forever. The odds have a way of catchingup with you, and defying them is an all-too-commonfallacy called "normalization of deviance." At NASA,this attitude laid the foundation for the Challengerand Columbia shuttle disasters.Second, it's not true that past safe outcomes alwaysoccurred even when countries let their big satellitesrandomly fall to Earth. Just the opposite is true -for decades, major spacefaring powers have takendeliberate and expensive steps to mitigate theground-impact hazards of satellites.All Russian spacecraft and U.S. military satellitesheavier than 15,000 pounds are deliberately steeredinto untraveled expanses of the far southern PacificOcean. NASA steered its Compton Gamma Ray Observatoryinto a precisely planned atmospheric re-entry in 2000,and tried (but failed) to do the same with the Skylabspace station in 1978.In last week's case, the Pentagon said it resorted tothe missile-intercept option because the spysatellite's guidance system was inoperable. Now, themix of motivations for making the missile attack canbe debated - but the up-front official claim aboutmitigating hazard cannot be glibly dismissed.Myth No. 3: The hydrazine on the spy satellite wasunlikely to reach the ground in any concentrationworth worrying about.Reality: Space officials were so concerned about thesatellite's full tank of hydrazine fuel because theybelieved it had frozen solid, due to the lowtemperatures aboard the spacecraft. They feared thatthe titanium-shielded "toxic iceberg" would surviveintact all the way to the ground and disperse aroundthe crash site, not in the upper atmosphere. Safetyofficials had never been faced with this type offalling material before.How dangerous is hydrazine? The chemical is consideredtoxic as well as flammable. U.S. space workers haveindeed survived massive short-term dosing by thechemical during fueling accidents, but they did so dueto the immediate application of pre-deployed safetymeasures.The U.S. might have been held legally responsible fordamage following the impact of such a hazardous cargoin a region with active agricultural exports ortourism.As with the Palomares incident 42 years ago, in whichtwo U.S. nuclear weapons fell to earth in Spain afteran aircraft accident, people outside the region mightbe so spooked that they stop buying the regionalexports and stop visiting its recreational facilities.The lost business alone could have cost hundreds ofmillions of dollars - compared with the estimated $60million cost of the missile intercept.Myth No. 4: The missile was aimed directly at the fueltank, in order to pierce it and let the hazardouscontents leak out.Reality: Sure, the fuel tank was the missile's maintarget - but the missile didn't have to hit the tankto crack it open. It's hard to imagine how thewarhead's guidance system could have spotted the tankanyhow, inside the blob that was the image of theentire satellite. Hitting the target dead center andthus smashing the entire satellite to smithereens wasthe easiest way to ensure maximum damage to the tank.Myth No. 5: The satellite disintegrated into more than3,000 pieces because the fuel exploded.Reality: Some Pentagon officials seemed to imply this,as evidence that they had achieved the goal ofdestroying the tank. But the kinetic energy involvedin the ultra-high-speed collision was more than enoughto impart enough force to cause the violent shattering- it certainly was orders of magnitude greater thanthe chemical energy that would have been liberatedfrom the ignition of the entire fuel supply, evenassuming it wasn't frozen. That collisional energy wasalso the reason that some pieces of the targetsatellite got thrown forward so energetically, eventhough the missile hit the satellite from the front.Most of the pieces fell through the atmosphere andburned up within a couple of days of the intercept. Asof Tuesday, the Air Force Space Command was reportedlytracking 17 fragments that were still in orbit.What's the harm in just letting all these myths lie?The danger is that the topic of weapons in space is aserious one requiring serious debate, especially inthis election year. Hanging onto the technical mythscould lead to misconceptions on one side of the debate("our missiles were so accurate they could make aprecision strike on the fuel tank") or the other ("theshootdown created a cloud of toxic debris that's stillin orbit").If we can "shoot down" the fuzzy thinking that hasfrustrated a serious exchange of views on thisimportant national security issue, that wouldrepresent a much more enduring contribution to thesafety of this planet than just protecting one randomspot from half a ton of plummeting poison.URL: http://www.msnbc.msn.com/id/23372844/«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»Paranormal_Research - Scientific Data, Health Conspiracies & Anything Strange Paranormal_ResearchSubscribe:... Paranormal_Research-