Failure of Glory satellite a major loss for climate change science

As the Taurus XL rocket boosting the $424 million Glory climate change research satellite roared off the launch pad from California's Vandenberg Air Force Base just after 2am PDT on March 4, NASA scientists and engineers from the rocket's maker, Orbital Sciences Corporation, were optimistic. A similar Taurus XL rocket failed in February 2009, resulting in the loss of the $273 million Orbiting Carbon Observatory, which was designed to preform high-resolution measurements of emissions of carbon dioxide from Earth. The rocket's fairing, a nose cone designed to shield satellites as it traveled through Earth's atmosphere did not separate properly, dooming the Orbiting Carbon Observatory to a spot at the bottom of the Pacific Ocean. Engineers redesigned the rocket, which did several successful launches over the past two years. But the rocket failed again for Glory's launch, and now the satellite lies useless beneath the South Pacific Ocean.


Figure 1. Climate responds to changes in the sun's radiation, dust (aerosol) particles, reflectivity of the surface (albedo) due to changes in land use, and concentrations of heat-trapping greenhouse gases such as carbon dioxide, methane (CH4), nitrous oxide (N2O), and halocarbons. Changes in any of these quantities are called "forcings", and can force the climate to be warmer (red bars) or cooler (blue bars.) The word "radiative" arises because these factors change the balance between incoming solar radiation and outgoing infrared radiation (heat) within Earth's atmosphere. Since 1750, the changes in radiative forcing as estimated by the 2007 Intergovernmental Panel on Climate Change (IPCC) show that human activities, primarily due to increases in CO2 and other heat-trapping gases, have forced the climate to a warmer state. This forcing is equivalent to 1.6 watts per square meter of extra energy arriving everywhere on Earth's surface. However, there is a large uncertainty (LOSU = Level Of Scientific Understanding) on how much particles in the atmosphere (aerosols) affect Earth's climate. The uncertainty bars for the direct effect of particles in the atmosphere (where they scatter away more sunlight) and the indirect effects (where they increase the amount of sunlight-reflecting clouds, by acting as nuclei that cloud drops can form around) are very large compared to the uncertainty bars for other forcings.

The loss of the Glory satellite is a particularly bitter blow, since the satellite was designed to study the greatest unknown in climate change science--the emissions, composition, and distribution of dust particles in the atmosphere. Particles in the atmosphere (called aerosols by scientists) come from a variety of human-caused and natural sources. Black soot from fires can act to warm the climate, particularly if these black particles fall on ice and snow. However, most particles emitted into the atmosphere reflect sunlight back into space, and thus cool the climate. As seen in Figure 1, both the direct effects of dust particles (where they scatter away more sunlight) and the indirect effects (where they increase the amount of sunlight-reflecting clouds, by acting as nuclei that cloud drops can form around) are poorly known. It was hoped that data from the Glory satellite could significantly reduce these uncertainties. There is no replacement mission for Glory scheduled, and Congress' current budget-cutting appetite makes it unlikely a replacement satellite will be funded anytime soon. A replacement mission for the failed Orbital Carbon Observatory is scheduled for February 2013, but that mission may be delayed, since is it being launched by the same type of rocket that failed in Glory's launch.

As Gavin Schmidt notes in a post over at realclimate.org on Glory's demise, working from space is hard, expensive, and risky. Rocket failures resulting in the loss of hugely expensive satellites are not uncommon, and it takes years to procure funding and build new satellites. But, there is no substitute for satellites; the global coverage and detail of data they provide cannot be matched by surface- or aircraft-based observations. We must continue to hurl them into space, or risk plotting our course blindly into the future with only a fuzzy idea of how our planet is changing.

I'll be back on Friday with an April Fool's Day post.

Jeff Masters