Pegasus XL Launch Timeline With NASA’s CYGNSS Microsats

An Orbital ATK Pegasus XL rocket and eight NASA microsatellites are ready for a second launch attempt at 8:26 a.m. Thursday.

The Pegasus carrying NASA’s $157 million Cyclone Global Navigation Satellite System mission, or CYGNSS, which will study the intensification of hurricanes to improve forecasting and tracking, will depart Cape Canaveral Air Force Station’s Skid Strip around 7 a.m. attached to the belly of Orbital ATK’s L-1011 Stargazer aircraft.

The aircraft will fly to an altitude of 39,000 feet, aiming for a drop zone more than 100 miles east of Daytona Beach.

A planned launch attempt on Wednesday was postponed after the spacecraft team uncovered a software issue during testing on Tuesday. Updated “flight data parameters” have been loaded into the microsatellites.

The testing on Tuesday followed a scrubbed launch try on Monday due to a problem with the hydraulic system that releases the Pegasus from the L-1011 aircraft.

That scrub may have been fortuitous, allowing time to spot the software problem before the microsatellites were put in space.

After the scrub, Orbital ATK flew a replacement circuit breaker in from Mojave, California.

It was installed and tested, and the aircraft was declared ready to go.

The CYGNSS mission will fly eight small satellites in a band around the planet, circling the tropics about 315 miles high.

The spacecraft will use GPS signals reflected off the ocean surface to calculate wind speeds in the middle of hurricanes.