Down in Flames

The head-on collision on February 21, 2008 of a ship-launched U.S. missile and a derelict U.S. spy satellite created instantaneous fireworks as the target disintegrated in a flash. In the hours that followed, much of the metal confetti left from satellite USA-193 burned up in the atmosphere in a man-made meteor shower that thrilled skywatchers lucky enough to be looking up.

But more than metal shards were crashing and burning across the skies of Earth; so, too, were the reputations of the science and space experts of American journalism. The U.S. military’s official explanation for the shoot-down was that on-board toxic chemicals made the falling satellite the most dangerous in history. But in a news media dance so unanimous that it practically looked choreographed, supposedly expert commentators pronounced the government’s official explanation to be a sham, and speculated instead on the secret militaristic motives behind it. Coverage of these views was largely credulous — most news stories about the claims didn’t even bother to seek out contrary views.

Real experts had always believed the official military line. NASA Administrator Michael Griffin, whose specialists performed an independent hazard analysis that confirmed the Pentagon experts’ results, attended the Pentagon press conference on February 14, 2008 when the intercept plan was disclosed. “The analysis that we’ve done is as certain as any analysis of this type can be,” he said then. Describing the satellite’s tank of toxic fuel, Griffin said that “the hydrazine tank will survive intact…[because] the hydrazine in it is frozen solid. Not all of it will melt. So [it] will land on the ground with a tank full of slush hydrazine that would then later evaporate.”

Another real expert, NASA space debris guru Nicholas L. Johnson, had been at a scheduled Vienna meeting of a subcommittee of the United Nations Committee of the Peaceful Uses of Outer Space a few days prior to the intercept. “Not a single member state questioned our motivation at that meeting,” Johnson told me. “In fact, our ‛transparency’ was praised not only by our close allies but also by those with whom relations are sometimes less cordial.” After the intercept, Johnson stayed in touch with his international colleagues. “In all my subsequent meetings withforeign space agency personnel,” he continued, “I have only received positive feedback on theopenness of the U.S. and on our decision to protect human life.”

In Moscow, the head of the civilian Russian Space Agency, Anatoly Perminov, told Russian reporters on February 16, 2008 that he, too, approved of the shoot-down plan: “In the given situation — if the satellite is indeed out of control — destroying it is the inevitable and right thing to do, I think.” Perminov was in a position to understand the risks and the options, and the U.S. decision seemed proper to him.

American military experts briefed the appropriate congressional committees, whose members issued statements and press releases endorsing the effort. None demurred.

But this broad technical and political support for the shoot-down was hardly mentioned in the days and weeks that followed what the Pentagon called Operation Burnt Frost. The consensus view among the so-called experts quoted in the national news media was that the official justification announced by the White House and the Pentagon was bogus. Instead, these commentators claimed, the shoot-down was intended to destroy super-secret circuit boards, or a nuclear power unit that had been kept secret. Or maybe the shoot-down was meant to respond to China’s anti-satellite test from thirteen months earlier. Or it was all a budget-boosting gimmick for the missile-defense program.

Such speculation ran rampant. For example, John Pike, the director of GlobalSecurity.org, told reporters that “the claim there was a danger from the fuel is not the most preposterous thing the Pentagon has ever said — but it seemed to be a bit of a stretch.” Military commentator Noah Shachtman, writing on Wired.com, approvingly quoted unnamed “space security experts” who told him: “The cynic in me says that the idea that this is being done to protect the lives of humans is simply a feel-good cover story tossed to the media” and “Having the U.S. government spend millions of dollars to destroy a billion-dollar failure to save zero lives is comedic gold.” James Lewis, director of the technology and public policy program at the Center for Strategic and International Studies, told reporters: “The official explanation seems a bit thin…. It was a surfeit of caution.” Dr. Geoffrey Forden, a physicist at M.I.T., told reporters that the reasons given for the plan “don’t sound too credible to me” and so “it certainly would seem that protecting people against a hazardous fuel was not what this was really about.” (When I asked him recently if he still felt that way, he assured me that “everything I’ve learned since then has just confirmed my opinions then.”)

Jing-Dong Yuan, an analyst at the James Martin Center for Nonproliferation Studies in Monterey, California, told the Al Jazeera television network that the military’s justification for the shoot-down was “not very credible according to scientists and analysts.” When I later asked him about this, he admitted that he didn’t have any expertise on the subject but was passing on other people’s opinions that he was not qualified to judge. But despite his ignorance, he didn’t flinch at giving Al Jazeera an anti-American “expert quote.”

Ivan Oelrich, vice president for strategic programs at the liberal Federation of American Scientists, participated in a WashingtonPost.com online chat before the intercept. “I believe that a reasonably skeptical person can be forgiven [for thinking] that there is more going on here than the administration claims,” he said. That suspicion is understandable — but it isn’t sufficient grounds for what Oelrich went on to say: “There are primarily political and military motives at work and the claims of concern for public safety are just a cover…. I do not buy the public safety argument. If the administration were concerned about public safety, they would take the millions of dollars spent on this intercept and spend it on vaccines for children.”

For many of these experts, the first and foremost proof that the satellite was no danger was provided by thousands of previous cases in which man-made objects had tumbled from orbit without causing terrestrial damage. For example, Michael Krepon, cofounder of the Henry L. Stimson Center, said, “In the history of the space age, there has not been a single human being who has been harmed by man-made objects falling from space…[so] there has to be another reason behind this.”

John Barry, on the Newsweek website the day of the intercept, said much the same thing. “Conspiracy theorists have had a field day,” he began — before proceeding to sympathize with them:

The suspicions are understandable [since] the odds against the satellite’s hitting a person are literally millions to one. History validates this confidence. In the 50 years of satellite launches, some 17,000 objects have plunged back to earth, according to the Pentagon…. There has never been a report of a human being struck by space debris.

On the other hand, the government’s experts argued that action was advisable based on existing safety standards. Nicholas Johnson pointed out to me that there is a long-standing risk level for satellite operations that provides a threshold beyond which hazard mitigation efforts are called for. The number is a one in 10,000 chance of human fatality.

In the past, heavy satellites with faltering control systems, such as the Compton Gamma Ray Observatory in early 2000, were deliberately deorbited over open ocean before control was lost and a random fall became inevitable. In the case of that satellite, NASA had estimated from the beginning that the chance of human casualties from a random fall was one in 1,000, ten times greater than the threshold.

Professional spacecraft operators know that those odds do not provide a blank check for random reentries. In fact, for most of the space age, almost all of the heaviest satellites (such as the Soviet Salyut space stations, U.S. military reconnaissance birds, Russian supply drones, and so forth) have not been allowed to fall randomly from orbit. Operators in the United States, the Soviet Union, and other major spacefaring nations have never assumed it was safe to just let them fall (as the commentators quoted above seem to think was the rule). Instead, these satellites, when able, used their rocket engines to terminate their flights safely over open ocean.

A close call from earlier in this decade shows just how wrong those experts are. On October 15, 2004, an off-course Chinese spy satellite’s film canister smashed through the roof of a four-story apartment building in Penglai in southwest Sichuan. Photographs through the smashed roof of the refrigerator-sized capsule sitting among splintered bricks and wood showed what might have happened if it had been carrying toxic chemicals — dozens of people could have been poisoned, many fatally. There are too few examples to generate meaningful odds of this happening, but out of several dozen landings of such capsules, at least one wound up inside a dwelling.

The Russians recognized the need for hazard mitigation, even at great expense, when they chose to deliberately deorbit the Mir space station in 2001. Two unmanned robot resupply drones, at a total cost of about $120 million (the price NASA was willing to pay for them if used to support the new International Space Station), were launched to supply the thrust to push the hundred-ton complex into an empty quarter of the South Pacific. At the time, nobody suggested the Russians had ulterior motives.

While USA-193 wasn’t as massive as most of the death-diving derelicts of the past, American officials decided that its tank of hydrazine fuel posed a unique hazard. Here, too, the consensus of commentators was clear and consistent: There was no danger. The tank would be consumed by the heat of atmospheric entry and disintegrate high above Earth.

Although NASA’s technical experts had done careful calculations in determining that the tank would survive reentry, Newsweek’s Barry lectured them on their ignorance of “the facts of physics” which prove that “friction from the atmosphere will roast the satellite to 7,500 degrees centigrade, hotter than the surface of the sun. [Therefore] the overwhelming probability is that the hydrazine tank…will simply explode as the hydrazine expands.” Time magazine science correspondent Jeffrey Kluger agreed: “The tank…is unlikely to make it through the heat and aerodynamic violence of the plunge that awaits it, meaning it will spill its contents high in the atmosphere.” The “hydrazine argument,” he concluded, “is suspect.”

Yousaf Butt, a staff scientist at the Harvard-Smithsonian Center for Astrophysics and a former research fellow at the liberal Union of Concerned Scientists, wrote that the hydrazine argument was just another White House lie: “The administration successfully pulled the wool over the public’s eyes. Again.” With great self-assurance, he added that “it is almost certain that the hydrazine tank would have exploded upon re-entry” and that “it continues to be difficult to identify any real technical merit to the hydrazine threat story proffered by the authorities.”

Even specialists with apparent credentials in spacecraft engineering joined in. In a letter published in Aviation Week & Space Technology a few weeks after the intercept, engineer Walter Holemans declared that the falling tank would have vaporized. “Imagine throwing a sealed tank of gasoline into a blast furnace,” he wrote. Based on this analogy, he declared that the hydrazine tank “would burst…. This would all happen 50 miles up and be of no danger.” As a result of this reasoning, “the argument about hydrazine is demonstrably false,” and consequently, “I conclude that the government was lying when it said the hydrazine tank was the reason for shooting a missile at a satellite.” The Belgium-born Holemans, founder of the small aerospace company Planetary Systems Corporation in Silver Spring, Maryland, fabricates satellite hardware for NASA, the U.S. Air Force, and other space customers.

However, this rosy scenario of “safe destruction” rests on technical misconceptions and unjustified analogies, such as equating atmospheric heating (due to air compression, not actually friction) to a “blast furnace.” For example, there is a widespread notion that meteorites falling to Earth arrive red-hot from their fiery bath, sometimes releasing super-heated fumes or setting brush fires. However well-established this myth may be in folklore and Hollywood films, it just isn’t true. Small meteorites actually fall to the ground cold, and under humid conditions can even form frost on their surfaces. True, thin outer layers are briefly exposed to very hot air, and much of those external layers can ablate away, but for most of the descent that air is thinner than even the vacuum inside Thermos bottles. Compared to the original sub-freezing temperatures in the object’s interior as it drifted through deep space, any regions of hot skin quickly equilibrate to the original cold levels. One example, cited in Brian Mason’s Meteorites (1962), is the Colby meteorite of 1917 which, when excavated from a small crater a few minutes after it fell, was observed to have frost on it despite its falling on a hot July Fourth afternoon in Wisconsin.

Nicholas Johnson explained to me the factors used by his NASA team to calculate the likely thermal history of the hydrazine in the satellite’s tank. The satellite’s owners, who had all the technical specifications, had calculated that its hydrazine fuel load would be frozen and substantially below zero degrees Celsius. Heat conducted into the structure would be absorbed by the thermal inertia of the ice, or if it reached sufficient levels, by the partially-melted hydrazine. “Hydrazine requires a tremendous amount of energy to go from solid to liquid,” he pointed out.

NASA’s detailed computations of the tank’s survivability were described in a paper by NASA contractor experts Robert L. Kelley and William C. Rochelle in Houston. Their results were summarized at the end of the paper:

Under the initial conditions and modeling techniques described above, it was found that the N₂H₄ [hydrazine] located inside of the titanium tank does not reach its melting temperature…. The N₂H₄ would have needed to absorb 43.15 MJ [megajoules] of energy…to reach 275 K [its melting point] from the start temperature of 214 K. It only absorbed 29.34 MJ, or about 68% of that.

As for outside experts who reached different conclusions, Johnson was skeptical. “They simply don’t have the expertise to do the analysis,” he said. “It’s just not easy.” There are complex thermodynamic processes at work: “Most important is re-radiation — a lot of the heat doesn’t go into the object,” he explained. It dissipates back out into the space surrounding the object.

Real independent experts who have actually done the thermal calculations confirm Johnson’s conclusion. For example, Andrew J. Higgins is an associate professor of mechanical engineering at McGill University in Montreal. He has a Ph.D. in aeronautics and astronautics from the University of Washington. Higgins is a researcher on the dynamics of explosions and detonations, hypersonic reacting flows, and simulating hypervelocity impacts in the laboratory (much more relevant when computing a real spaceflight process than, for instance, Butt’s degree in nuclear astrophysics). Responding to what he saw as widespread media misreporting of the basic physics of the controversy, he published some calculations online and argued that Butt’s claims that the tank would be destroyed during the fall were

written in apparent ignorance of well-established heat transfer relations for spacecraft reentry. Simple estimates of the total heat transfer to the tank upon reentry, available in any number of aerospace textbooks, show that the heating of the tank would probably not have been sufficient to melt the hydrazine entirely, much less vaporize or ignite it.

Higgins and Butt argued with one another online (both on The Space Review and the “Arms Control Wonk” blog), and following a sequence of persuasive mathematical arguments and laboratory results from Higgins, Butt dropped out of the conversation with a sarcastic farewell: “The conclusions of my argument stand,” he stated, ignoring the points Higgins had made. “I hope you continued grants/contracts from NASA for your fine towing [sic] of the line.” This was a crude personal attack, hinting that Higgins has mercenary motivations for holding opinions that Butt can’t refute.

In their rush to gin up ulterior motives for the shoot-down, several commentators made mistakes about basic facts. Newsweek’s Barry, raising a rumor first circulated in Moscow (he did not cite his source), said that the U.S. government could be lying to hide the fact that there was a nuclear reactor aboard USA-193. “The U.S. uses nuclear reactors to power satellites sent on distant space probes,” he wrote. That is simply false: all such probes use radioisotope thermal generators with much more benign radioisotope fuel. And Ivan Oelrich made a reverse mistake in his WashingtonPost.com chat: “We and the Russians used to put radioisotope generators on satellites in Earth orbit. In fact, many years ago one reentered the atmosphere over Canada and scattered radiation.” His first sentence was correct, but his second wasn’t: The Soviet satellite he refers to was carrying a full-blown nuclear reactor, with much nastier radiation sources. And there was more than one: at least three and probably more such satellites fell from space over the history of the program.

Unhinged allegations from American “experts” helped set the tone around the world. “The Pentagon has therefore fabricated the hydrazine fairy tale,” wrote Libération (Paris). “The reason given by the Pentagon — namely, the danger presented by its toxic fuel, has perplexed space circles,” added another French paper, Le Figaro. The London Independent concluded that “almost nobody believes the public health rationale offered for the missile strike.”

Admittedly, the paucity of technical information released by the government makes it difficult to know precisely how the Department of Defense (DoD) and NASA reached their conclusions. But specialists like Higgins showed that any competent aerospace engineer could work from first principles and determine that tank survival was at least plausible. This stands in contrast to the media poseurs, like Oelrich, who wrote that “the public safety argument is hollow. It does not stand up to any sort of cost/benefit analysis. Superficially this looks quite reasonable, a great idea, but it doesn’t stand up to analysis. But analysis takes time.” But what analysis had Oelrich done himself? None at all.

According to NASA’s Johnson, his team’s analysis showed probabilities of human endangerment that “were all much riskier than the accepted standard.” The results of the DoD analysis weren’t disclosed until July 20, 2008, when Lieutenant General Henry “Trey” Obering, then head of the U.S. missile defense effort, appeared on a cable TV show about the shoot-down: “It varied depending on which experts we talked to, but [we got] anywhere between 1 in 45 and 1 in 25 chance of that [i.e., human casualties] occurring.”

“Clearly nothing prior to USA-193 rose to that level,” Johnson told me. “The risk posed was much higher than any risk we’ve ever seen” from a falling satellite.

General Kevin Chilton, commander of the DoD operational command that oversaw the conversion and launch of the missile, told me in a phone interview that it was the specific contents of this satellite that elevated the hazards far above the threshold for mitigation. “If it had just been hardware we would never consider these extraordinary measures,” he told me. The presence of the toxic chemical, in a tank completely full because the payload had failed immediately after launch, was the unusual driving factor. Johnson concurred: “The odds of injuring many people was much higher then we’d seen in the past,” he had explained. “It was no longer just physical trauma injury.”

In terms of the ultimate decision driver, Chilton and Johnson both referred to what they called the “regret factor” — the issue of what might follow a decision to do nothing that led to a human tragedy. “At the end of the day,” Chilton told me, “how could we look somebody in the eye, who had relatives killed or injured, how could we have that conversation?” Chilton attended the White House briefings where President Bush was given the options and the odds, and he remembers Bush’s specific directive that if something could be done to mitigate the risk to human life, it needed to be done.

At the meeting, Chilton also raised other threats. “There’s a risk that people will say it’s an ASAT test,” he recalls pointing out. Contrary to some of the overheated speculation from the commentariat, Chilton told me that missile defense officials actually argued against the effort, seeing it as a diversion of time and resources from their existing research and testing activities; Johnson, too, recalled that diplomatic experts advised that the event would bring bad publicity, based on assumed “hidden motives.” But in Chilton’s telling, President Bush responded, “I don’t care what people will say, we’re doing it for the right reason, and it’s transparent.”

Perhaps the most persistent skeptic among the self-acclaimed experts has been Yousaf Butt. Six months after the satellite intercept, he published an article in the Bulletin of the Atomic Scientists criticizing the analysis that Kelley and Rochelle did for NASA. “Despite its optimistic oversimplifications, the released study indicates that the tank would certainly have demised high up in the atmosphere,” Butt claimed, grossly misreading what Kelley and Rochelle wrote. “I am simply telling you what the report says,” he proclaimed in an e-mail to me.

Johnson, head of the NASA study team, disagrees. “Dr. Butt has performed a profound disservice to this country and to the honorable men and women of Operation Burnt Frost,” he told me. “His attempt to justify preconceived notions by intentionally misrepresenting a simple working paper is an affront to the scientific profession.”

“Prior to the release of his recent claims of ulterior U.S. Government motives and shoddy analysis,” Johnson continued,

I personally informed Dr. Butt that the paper in question [by Kelley and Rochelle], one of only two unclassified and, hence, releasable documents produced by NASA during Operation Burnt Frost, in no way represented the breadth and depth of the thorough investigations which have been conducted by NASA and by other U.S. government organizations concerning the survivability of the propellant tank of the USA-193 spacecraft. Independent assessments by specialists knowledgeable of reentry physics and the particulars of USA-193 reached a consensus on the high likelihood of the survival of the tank and its contents.

Butt did not publish these portions of Johnson’s e-mails to him.

Butt’s claims were good enough for the press. Noah Shachtman’s Wired.com story about Butt’s claims was titled “NASA Study Casts Some Doubts on Sat Shoot-down” — even though it was only Butt’s misinterpretation, not the NASA study itself, that cast any doubts. United Press International ran a story identifying Butt as “a former NASA employee,” implying he was some sort of whistleblower coming out to denounce a study he had watched NASA falsify. The headline in U.S. News and World Report claimed that “New Evidence Contradicts Official Explanation” — except that there was no new evidence, just an old, repeated interpretation and accusation. The U.S. News reporter twisted Butt’s claims even further, writing, “Newly released documents show that officials knew a satellite falling to Earth posed no threat” (emphasis added). In other words, government officials lied to the public — when even Butt only claims that the experts misunderstood their own professional work and incorrectly believed it implied there was a threat.

Thus has the media narrative solidified. Chances of dispelling this interpretation now seem slight. The government’s hopes — that explaining its motives and being transparent about Operation Burnt Frost would reduce misunderstanding — ran afoul of domestic and international politics. By and large, the media has portrayed the shoot-down as aggressive and militaristic, an excuse to threaten China, a back-door test of “space weapons.” A well-defined and thoroughly-researched technological hazard assessment has been buried in misinformation. This does not bode well for the next time a space hazard requires action.