Pegasus launches hurricane-hunting satellites for NASA

A fleet of hurricane-hunting NASA microsatellites safely reached orbit Thursday morning after launching high over the Atlantic Ocean off Florida's East Coast.

At 8:37 a.m., an hour after taking off from Cape Canaveral Air Force Station, a carrier aircraft dropped Orbital ATK's Pegasus XL rocket while flying at 39,000 feet and 125 miles east of Daytona Beach.

The 57-foot, 51,000-pound Pegasus fell for five seconds in blue sky above a blanket of clouds, then ignited its first-stage engine to begin rocketing toward space.

Less than 15 minutes later, flying 315 miles over the planet, four pairs of microsatellites, each the size of a carry-on suitcase and weighing about 60 pounds, pushed away from the rocket's third stage in 30-second intervals to start the $157 million Cyclone Global Navigation Satellite System mission, or CYGNSS.

"When the last two came off, it felt fantastic," said Chris Ruf, the mission's lead scientist from the University of Michigan. "We’re right there where we were expecting, so it’s good news."

The mission aims to improve forecasting of hurricanes' intensity by measuring ocean surface wind speeds in the center of storms.

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The small, relatively low-cost satellites will do that by receiving GPS signals that bounce off the ocean. Strong signals indicate the ocean is calm and winds are light, while weak signals mean rough seas and high winds.

Existing satellites are not well equipped to gather that information from space, because their instruments operate at frequencies that can't penetrate heavy rain. Also, several days may pass between their passes over the hurricane.

Measurements of peak sustained winds are best gathered from "hurricane hunter" aircraft that can make only limited runs over parts of a large storm.

That information is critical to understanding if a storm is gaining strength and how damaging it may be when it hits land, helping to model potential storm surge, for example.

Forecasters over time have gotten much better at predicting hurricane tracks, but not their intensity at landfall.

The eight CYGNSS microsatellites will fly in a band over the tropics, the busiest storm region, flying over the same area on average every seven hours.

The Earth science mission is funded for at least two years, and could be extended.

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Thursday's launch followed a scrubbed first attempt on Monday, caused by a failed circuit breaker in the hydraulic system that releases the solid-fueled Pegasus from Orbital ATK's L-1011 Stargazer carrier aircraft.

A planned Wednesday attempt then was postponed after the Michigan team spotted a wrong flight parameter in the satellite's software during tests on Tuesday. A fix was uploaded.

With those issues resolved and an excellent weather forecast on Thursday, the L-1011, a modified airliner built in 1973, took off again just after 7:30 a.m. from the Skid Strip at Cape Canaveral Air Force Station with the rocket and satellites attached to its belly.

The mission was the 43rd overall by a Pegasus, but the first since 2013 and the first from Cape Canaveral in more than 13 years.

Following tradition, NASA's Launch Services Program, based at Kennedy Space Center, inscribed a name on the rocket's nose cone. The choice for the CYGNSS hurricane mission: Matthew.

That was a tribute to Hurricane Matthew, the powerful storm that threatened much of the East Coast, delayed the CYGNSS mission's planned November launch and caused millions of dollars of damage to KSC and Cape Canaveral Air Force Station.

"We thought it was appropriate," Alicia Mendoza-Hill, the NASA's mission manager, told NASA TV.

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Meanwhile, preparations are in progress for a Sunday afternoon liftoff of the year's final mission from the Space Coast.

A United Launch Alliance Atlas V rocket is targeting a 1:27 p.m. blastoff from Launch Complex 41 with the EchoStar 19 commercial communications satellite.

Contact Dean at 321-242-3668 orjdean@floridatoday.com.And follow on Twitter at@flatoday_jdeanand on Facebook atfacebook.com/jamesdeanspace.