by Adam Voiland Thursday, January 5, 2012
On a warm afternoon in early March, the Taurus XL rocket that was prepped for launch at Vandenberg Air Force Base in Southern California looked more like a giant chopstick standing on end than a potential game changer in the debate over climate change science. The barrel-shaped satellite that the rocket carried — named Glory — was designed to deliver critical information about small airborne particles called aerosols. The elusive particles account for much of the uncertainty in climate models, and data from the satellite would have helped scientists determine more of the aerosols' key properties than ever before. Instead, before dawn the next morning and just minutes after launch, Glory’s remains crashed into the southern Pacific Ocean near Antarctica.
For the dozens of scientists and engineers who spent 10 years working on Glory and its instruments, the loss was heartbreaking. It has also been felt by the entire climate science community, who hoped the mission would provide much-needed aerosol data for use in the next Intergovernmental Panel on Climate Change (IPCC) report. The following recounts the sad tale of Glory’s demise.
In California, dozens of people have filtered into mission control at Vandenberg Air Force Base. Most of the engineers sit in horizontal rows on rolling chairs. Some wear headsets. In the front of the room, a movie-theater-sized screen displays the launch site from multiple angles. On one side of the big screen, stacks of numbers flip by, second by second. Most are counting down to 2:09 a.m. PST.
That’s the launch time for Glory, a long-awaited addition to NASA’s fleet of 14 satellites that monitor Earth’s vital signs. NASA built most of them, although French, German and Japanese space agencies have also contributed instruments and expertise.
They’re not weather satellites; their goal is to help scientists figure out how our planet works as an interconnected system, and to determine whether the climate is changing over time. Some of the satellites measure ice thickness. Others look at ocean height and salinity. Still others detect gases in the atmosphere, like water vapor and carbon dioxide. Some track clouds and cloud particles; others measure the greenness of vegetation from space. Not even the size of a car, Glory was designed by NASA engineers to monitor the intensity of the sun’s energy as it enters Earth’s atmosphere and to determine how airborne particles absorb and reflect sunlight.
Michael Mishchenko, Glory’s lead scientist, sits at home in New York City, nervously watching NASA TV. During the first launch attempt a week and a half before, aborted by mission managers just a few minutes before liftoff, Mishchenko had been among a crowd of hundreds of well-wishers, peering up at the sky from a golf course a few minutes away from Vandenberg, cracking jokes with colleagues and lamenting the scarcity of physics students willing to work with satellite data. This time, however, obligations at NASA’s Goddard Institute for Space Studies (GISS), located near Columbia University in New York City and one of the lead institutions behind the Glory mission, prevented him from traveling.
The Ukrainian-born Mishchenko has spent his career studying how aerosols — bits of airborne dust, volcanic ash and the like — scatter light. He has devoted the last 10 years to the Glory mission because of his concern that climatologists aren’t using the right numbers when they tally Earth’s energy budget — the amount of energy entering and exiting our atmosphere. If more energy comes in than out, he says, physics dictates that the planet will warm. If the reverse is true, it will cool. Aerosols reflect or absorb light to varying degrees depending on their composition, size and shape, but the best estimates to date are still highly uncertain because of the difficulty in measuring their abundance and distribution.
That means global warming could be more severe — or less so — than scientists think. Mishchenko’s hopes for reducing the uncertainty lie in an instrument called the Aerosol Polarimetry Sensor, which is nestled in the nose of the Taurus XL.
“Weather is ‘go,'” the Air Force meteorology officer reports. The engineering team is still running through dozens of checks: They run a series of tests on the rocket’s and spacecraft’s electronics to make sure every last part is functioning as expected; they power things up and power them down. They “trickle” charge the battery to ensure it remains at full capacity. Everything is proceeding smoothly.
Still, mission control is on edge. The last time NASA tried to launch a climate mission on a Taurus XL, two years ago, it ended in spectacular failure. The clamshell-shaped nose cone that shrouds the tip of a Taurus — called a fairing — never separated from the rest of the rocket. The extra weight meant the rocket lacked the thrust it needed to escape Earth’s gravity, so instead of achieving orbit, it rained into the Pacific in a shower of debris a few minutes after liftoff.
In the two years since the incident, NASA and Orbital Sciences Corporation, the Virginia-based company that designed and built the rocket, conducted an extensive review and redesigned the entire system. They replaced a “hot-gas” system that pushes the fairing apart with what’s called a “cold-gas” system that uses pressurized nitrogen instead. The cold-gas system is nearly identical to one used on another class of Orbital rocket, the Minotaur IV, which has launched successfully three times in the last two years. The problem, the engineers believe, is now behind them.
“Ready to proceed into hot count,” the lead launch engineer says over the intercom.
The engineers have turned off external power. The spacecraft is now running on battery power. The project manager on Glory, Bryan Fafaul, wired on multiple cups of coffee, sits nervously in the control center. Like Mishchenko, there’s nothing he can do at this point. His team of engineers designed and built the spacecraft, not the rocket that’s carrying Glory into orbit. Now, Fafaul has to step aside and let the rocket people launch it.
Fafaul is proud of his team. From the get-go, prepping Glory for launch proved to be a thorny endeavor. When NASA announced in 2003 it would fly Glory, the agency’s headquarters gave Fafaul’s team a mothballed satellite left over from a canceled mission rather than fund a new spacecraft. The team soon realized that the hand-me-down needed a thorough overhaul, and in the course of retrofitting it, the engineers had to grapple with a steady stream of glitches related to the aging hardware.
A defect in a key computer chip, as well as residual cleaning solvent in the motor that is supposed to rotate Glory’s wing-like solar arrays, caused delays. At one point, problems building Glory’s aerosoldetection instrument nearly ended the mission. Early in 2005, NASA management decided to cancel Glory, but then changed course six months later and revived the mission. Eventually, the project ended up so far over budget that it triggered congressional scrutiny. Despite the setbacks, however, the Glory team pushed onward.
Engineers have powered up the rocket’s flight termination system, a safety feature that would blow the Taurus XL up if it veered off course and headed toward land or if some other mishap occurred during launch.
On Twitter, excitement grows: an enthusiastic tweet from someone aboard a NASA tracking plane circling in the Pacific wishes Glory a safe flight.
Satellites remain a risky and expensive business, and in many cases, there are no second chances or backup instruments. Money for NASA earth science missions has been tighter than ever in recent years, especially for small satellites like Glory. But it wasn’t always this way.
Three decades ago, before the collapse of the Soviet Union and the end of the space race, NASA had funding to develop ambitious missions to study Earth. In the 1980s, management drew up plans to use the space shuttle to launch massive astronaut- tended, polar-orbiting and Earth-observing platforms in conjunction with the space station program. But that effort lost momentum after the Challenger disaster in 1986. Still, Congress and the White House remained committed to earth science, and in 1990 they approved a $17 billion “Earth Observing System” that envisioned unmanned satellites rather than astronaut missions.
Had it come to fruition, the system imagined would have been NASA’s third-costliest project in history, trailing only the Apollo and Space Shuttle programs. It would have lofted three pairs of 15-ton satellite platforms, each containing 12 to 15 instruments, into orbit on expensive yet reliable heavy-lift Titan IV rockets over a period of 15 years. Each pair was designed to last for five years. Soon after its approval, however, lawmakers started to balk, and after the Soviet Union collapsed, NASA saw its entire budget shrink. Just a year after approving the $17 billion Earth Observing System, in 1991, Congress slashed funding for the project to $11 billion, calling for less ambitious missions with fewer instruments that would fly on smaller rockets. Subsequent “rescoping” of the observing mission in 1992 cut funding to just $8 billion, and in 1994, budgetary “rebaselining” chipped away another $750 million.
In recent years, as climate change has become ever more controversial, lawmakers have continued to trim NASA’s earth science projects. Missions are smaller, rockets are cheaper, and plans to develop new instruments are either put on hold or are scrapped before they can get under way.
Just a few weeks before Glory’s launch date, the White House ordered NASA to cancel two highpriority earth science missions. And some members of Congress are trying to cut earth science from NASA’s budget completely.
For Glory, the years of trimming and cutbacks mean that the mission has ended up on a rocket that, although newly designed, costs only about half as much and has proven to be less reliable than other options.
The Taurus XL is still marching flawlessly toward launch.
In New York, Mishchenko can feel his adrenaline rising. He and his colleagues at GISS have worked tirelessly to get to this moment, and it’s hard for them to believe it has finally arrived.
Scientists at GISS were some of the first to recognize the importance of aerosols for the global climate and to make significant progress toward modeling them. In 1991, when Indonesia’s Mount Pinatubo spewed millions of tons of ash and gas into the atmosphere, including translucent, reflective sulfate particles, GISS Director James Hansen predicted that global temperatures would drop. It made sense: Sulfates scatter and reflect incoming sunlight back into space, allowing the atmosphere to cool. He predicted a halfdegree temperature drop for about two years. And that’s exactly what happened.
But sulfates, which come from coal burning and other industrial processes, as well as volcanoes, aren’t the only aerosols floating about. A diverse group of particles, including sand and mineral dust from sandstorms, sea salt particles flung into the air from waves, bits of black carbon spewed from forest fires and automobiles, and volatile organic compounds emitted from forests and phytoplankton, also inhabit the atmosphere. Some reflect light, much like sulfates. Others, including black carbon, absorb it and cause the atmosphere to warm rather than cool.
Despite advances in the past few decades, researchers realize they are still a long way from fully appreciating the complexity of atmospheric aerosols and how they affect the climate. It’s important, for example, to understand how much human-produced aerosols contribute to the overall load of particles in the atmosphere, but it isn’t always easy to separate the two types out. In fact, in Mishchenko’s view, current understanding of aerosols is not just limited, but is deeply inadequate. Of the 25 climate models included in the IPCC’s Fourth Assessment Report, he says, only a handful considered the effects of aerosols other than sulfates. Less than a third accounted for aerosol impacts on clouds, even in a limited way, and of those, none considered anything other than sulfates.
By distinguishing among aerosol types in unprecedented detail, Glory’s Aerosol Polarimetry Sensor is poised to start filling in gaps in current climate models that scientists believe will improve their accuracy. The sensor will use six telescopes to observe subtle differences in the orientation of light wave vibrations — a property called polarization — as light waves collide with aerosol particles. Polarization has been used to study the atmospheres of other planets, but Glory’s instrument will be NASA’s first attempt to use the technique to study Earth’s atmosphere.
The launch manager polls the lead engineers and receives the final go-ahead.
At T minus 3 minutes, the Taurus XL is armed.
A computer capable of performing billions of operations per second takes control of the launch. Aborting the mission is no longer an option.
The numbers on the board continue counting down. The room holds its breath.
T minus five seconds, four, three, two, one… “LIFTOFF! Liftoff of the Orbital Sciences Taurus XL rocket and the Glory observatory to probe the natural and man-made forces driving Earth’s climate,” proclaims the launch commentator on NASA television.
Thirty seconds in, and the Taurus XL is roaring over the Pacific at nearly 1,300 kilometers per hour, faster than the speed of sound. Fifteen seconds later and it’s still traversing the densest part of the atmosphere — the aerosol-rich troposphere. After 55 seconds, the rocket is 16 kilometers up, speeding along at about 3,200 kilometers per hour, four times faster than a commercial jet.
The second stage ignites a minute and 45 seconds after launch. What’s left of the first stage begins tumbling toward the ocean far below.
Another minute later, and with Glory still encased in the nose cone, the rocket reaches outer space at about 100 kilometers above sea level. The Taurus XL continues its climb, reaching a blistering 15,300 kilometers per hour. After 2 minutes and 45 seconds, the second stage has burned through.
The Taurus XL continues to soar, but suddenly the voice on the intercom sounds strained. “The vehicle speed is indicating under-performance,” an engineer says. “We still have no indication of the fairing separating.”
Seconds pass. All is silent at mission control at Vandenberg.
Another voice on the intercom: “Attention all stations, this is the NASA launch manager. We have had a contingency on the Glory mission.”
Back in New York, Mishchenko stares at his computer screen in disbelief. He slumps back in his chair. He recognizes the cryptic language of the engineers. This is not just a contingency: The Glory mission, just like the earlier mission, has failed. Mishchenko shuts his eyes, telling himself this is just a bad dream. He opens them. The deflated look on the launch commentator’s face remains.
Even so, the Taurus is still going. Four minutes and 30 seconds after launch, its trajectory plateaus and it begins to coast like a ballistic missile. The last of the four engines ignites. Once again, the fairing has failed to jettison from the rest of the rocket. The Taurus XL lacks the thrust it needs to escape Earth’s gravity.
Mission controllers watch as the rocket peaks and then slowly arcs back toward Earth. The atmosphere shreds the rocket and spacecraft upon re-entry. The remains fall toward the southern reaches of the Pacific.
It’s all too familiar. In a press conference after the launch failure, a reporter asks where Glory has crashed. A NASA official, near tears, says it has probably hit the ocean at the same spot the previous mission did.
Within a day, Fafaul and Mishchenko have received hundreds of emails from people expressing condolences. A failure of this magnitude is treated like a death at NASA and within the climate science community.
Everything at mission control is impounded — notes from the engineers, computers, photos of the fairing. There will be investigation panels and reports. NASA is pulling together a mishap investigation board. Engineers had spent more than a year redesigning the fairing release system after the previous mission crash. They believed they’d fixed the problem. Clearly, they hadn’t, or they’d created another one in the process. Either way, they now had to figure out what went wrong, again.
The company that built the rocket, which is scheduled to launch another earth science satellite on a Taurus XL in the next two years, could lose its contract. But the thoughts of the earth scientists involved are elsewhere. Their concern is that key questions and uncertainties about climate science — questions that could have been resolved years ago had a more ambitious Earth Observing System been built — remain.
Mishchenko says he is undeterred. “There is no time to mope,” he says. “The world needs these measurements. We must find a way to make them, and we will.”
Two days after losing Glory, NASA Headquarters instructed the project’s science team to determine, with the help of a broader group of aerosol specialists, if it is worthwhile to rebuild and launch a carbon copy of Glory’s aerosol instrument.
Following the earlier mission on a Taurus XL that failed, NASA did decide to rebuild. That mission, the Orbiting Carbon Observatory 2, will launch no earlier than February 2013. However, at the end of June, Space News reported that NASA put on hold plans to launch the observatory and suspended payment to Orbital Sciences Corporation, as the agency continues to review the Glory failure and consider its options for putting more satellites into orbit. NASA managers said the agency is unlikely to use another Taurus XL rocket unless it can be proven reliable.
In the meantime, the fate of Glory’s aerosol sensor remains in limbo. Though the aerosol team’s report remains in draft form, to Mishchenko, the way forward is perfectly clear: to rebuild. And indeed, the Glory engineering team has already developed a draft schedule to start rebuilding the instrument this year, to launch by July 2015, and to start delivering aerosol data by fall 2015.
If NASA managers don’t approve that plan, it’s unlikely that the agency will launch another mission capable of measuring aerosols in the detail Glory might have for another decade or more. In the meantime, scientists will continue squeezing what information about aerosols they can get out of existing satellite data while hoping they will eventually get their hands on better measurements.
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