Weathering the Storms

At a time of year notorious for the thick fog of “June gloom,” scientists received the boon of uncharacteristically clear weather for the launch of the Ocean Surface Topography Mission (OSTM) Jason 2 satellite from Space Launch Complex-2 (SLC-2) at Vandenberg Air Force Base early Friday morning. Weather conditions were so clear, in fact, that a number of the photographers documenting the launch were heard grumbling at the unexpected brightness of the Delta II rocket’s white hot exhaust plume as it streaked across the star-studded night sky. Weather wasn’t the only thing on the side of the NASA-coordinated team, and scientists watched via a camera mounted on the rocket as the final stage separated 55 minutes after liftoff. Then, the control room crew observed the solar array deploy flawlessly as the satellite began its orbit. “Everything we could have asked for happened,” said Omar Baez, a NASA launch director who came from Florida’s Kennedy Space Center to help with the launch.

Jason 2 is a continuation of the European Topex/Poseidon mission and the Jason 1 flight, which were initiated to gather sea surface height data. Jason 2 is a collaboration between NASA, NOAA, and the European Organisation for the QQQ Exploitation of Meteorological Satellites (EUMETSAT), with the Delta II rocket provided by Centre National d’Etudes Spatiales (CNES). CNES was the main force behind the first project, which was launched in 1992. Data provided by the project showed scientists that sea level rise-at 0.12 inches per year since 1993-is about twice the rate indicated by traditional tide gauge data, providing a basis for speculation that sea level rise has accelerated recently. Because the world’s oceans absorb heat and are a regulator of global climate, Jason 2 includes sea surface temperature instrumentation in addition to the altimeter that helps it determine sea level height.

While monitoring the ocean’s surface for tsunamis is beyond the capability of Jason 2-a vast array of satellites would be needed to provide complete and constant coverage of the ocean’s surface-scientists are hopeful that the improved technology in the new satellite will enable more accurate hurricane prediction. According to Alan Buis, a spokesperson for NASA’s Pasadena-based Jet Propulsion Laboratory, sea level is linked to the amount of heat stored in the water near the surface. While it will be working in conjunction with Jason 1, the new Jason has better eyes that will enable it to take measurements 50 percent closer to shore than its predecessor. “This will be useful for oil drilling operations, fishermen, and sailors,” said Buis. “There are other topographical satellites in orbit, but the Jason satellites are the most detailed and can provide the kind of data oceanographers are looking for.” Real time data collected by Jason 2 will be made immediately available by NOAA and EUMETSAT. “NOAA will use this data to help with hurricane intensity forecasts.”

Jason 2 is one of many satellites benefitting from a polar orbit, which allows more complete coverage of the Earth’s ice-free oceans. Vandenberg Air Force is ideally situated away from population centers to allow rockets with north, south, and west trajectories to launch without worry of jettisoned stages inadvertently falling upon the unsuspecting urban public. Eastward launches from the Kennedy Space Center in Florida have the added energy of the Earth’s rotation, but the typically southbound polar orbit launches require a bigger rocket to carry the satellite into the proper trajectory. To launch a polar orbit satellite from the East Coast would require a dogleg in the course that would significantly cut into the payload capability of the rocket. Simply put, bigger rockets and a shorter path mean more gear can be carried into space, so Vandenberg is the choice pick for these complex weather satellites. Since 1966, SLC-2 has been used for the launch of Delta, Thor-Agena, and now, Delta II rockets. Operated by the Air Force’s 30th Space Wing, SLC-2 was also used for the August, 2007 launch of the Phoenix Mars landing module, which entered Mars’ atmosphere on May 25 of this year.