Orbital Sciences Corp., of Dulles, Va., has been awarded a $55 million launch services contract with NASA to launch the space agency’s Cyclone Global Navigation Satellite System mission, or CYGNSS, from Cape Canaveral Air Force Station in October 2016. The mission, led by the University of Michigan, will launch on one of Orbital’s Pegasus XL rockets, which will be fired from a Stargazer L-1011 aircraft.
CYGNSS aims to help scientists better understand the characteristics of tropical storms and hurricanes by enabling scientists to probe key air-sea interaction processes that take place near the core of those storms, which are rapidly changing and play a critical role in the genesis and intensification of hurricanes. Measurements of ocean surface winds over the whole life-cycle of the storm, in and near the hurricane inner core, including regions beneath the eye wall and intense inner rain bands that could not previously be measured from space, will be measured by CYGNSS, and the measured wind fields—when combined with as-frequent precipitation fields (produced by the Global Precipitation Measurement (GPM) core satellite and the current constellation of precipitation imagers)—will provide coupled observations of moist atmospheric thermodynamics and ocean surface response and enable new insights into TC inner core dynamics and energetics.
“There’s been a huge amount of improvement in the last 20-30 years because of satellites in our ability to forecast where a hurricane is going to go, and there’s been essentially no improvement whatsoever in our ability to forecast how strong it’s going to be when it gets there,” said CYGNSS Principal Investigator Prof. Christopher Ruf from the University of Michigan Department of Atmospheric, Oceanic and Space Sciences. “When Katrina made landfall in New Orleans in 2006 the track for the hurricane was very accurate, it was right on, they knew exactly where, and when, it was going to make landfall. But their forecast for how strong the storm was going to be was way WAY off, the storm surge that caused the flooding was three times higher than was predicted. That sort of mistake in forecasting is exactly what we are going after with this new mission.”
The data gained by CYGNSS will help to create faster and more accurate weather forecasts, which will surely save lives when future storms threaten large populations. In order to accomplish this, a constellation of eight small satellites, or micro-satellite observatories, will need to ride to orbit together, where they will receive direct and reflected signals from GPS satellites (the direct signals pinpoint observatory positions, while the reflected signals respond to ocean surface roughness, from which wind speed is retrieved). Each observatory will be capable of measuring four simultaneous reflections, resulting in 32 wind measurements, per second, across the globe.
“Traditionally to measure what’s going on in a hurricane you can’t use satellites because the strength of the hurricane is determined by what’s going on in the middle of the hurricane, and we can’t see in the middle with traditional satellites,” said Ruf. “We, the research community, have developed a new technique to see into the middle of hurricanes, through the rain, using GPS signals. By analyzing the details of how the signal gets distorted by the ocean you can figure out how strong the winds are.”
The Pegasus XL rocket was made to launch payloads just like CYGNSS—it’s an inexpensive way of launching small payloads into space. Launching small payloads from aircraft already in-flight is much cheaper than using a stage motor to lift each Pegasus off the ground. Instead, Stargazer will carry Pegasus and its CYGNSS payload out over the Atlantic Ocean, cruising for about an hour until reaching a standard launch altitude of around 40,000 feet before being released. After a five-second free fall the Pegasus will fire the first of its three ATK-manufactured motors, riding uphill for about 10 minutes before reaching a top speed of 17,000 mph, some 460 miles above the Earth.
Overall, the Pegasus rocket has proven itself reliable. Out of 42 launches since 1990, the Pegasus has failed to deliver its payloads just three times—the last such failure having occurred over 17 years ago.
The $55 million firm-fixed price launch-service task order contract awarded to Orbital for the CYGNSS mission covers spacecraft processing, launch service payload integration, tracking and data, and telemetry, in addition to other launch support requirements.
“We’re going to be the first satellites up there that can penetrate through the rain, and because of that we’re going to make fundamental improvements in how well we can forecast the strength of a hurricane,” added Ruf. “Being able to do that makes all the difference in your preparation, whether to evacuate or not, whether to open up the levees and let the water drain and all the sort of things you do in preparation for a hurricane.”