WorldView-4 set to launch after months long delay
After nearly two months of delays, United Launch Alliance (ULA) is once again gearing up to fly an Atlas V rocket with DigitalGlobe’s WorldView-4 satellite. The 15-minute launch window is scheduled to open at 10:30 a.m. PST (1:30 p.m. EST / 18:30 GMT) Nov. 11 at Vandenberg Air Force Base in California.
Weather is expected to cooperate for Friday’s launch with an estimated 100 percent chance of acceptable conditions at the planned time of liftoff. Flying in the 401 configuration, the rocket will have no strap-on solid rocket motors and will have a 13-foot (4-meter) wide fairing encapsulating the WorldView-4 satellite.
The mission was originally aiming to get off the ground back on Sept. 16. However, 30 minutes before launch, a small hydrogen leak was detected on ground-side equipment. ULA CEO Tory Bruno said on Twitter that ice had formed around an umbilical.
This was the first time in four years – some 30 launches – that a launch of an Atlas V rocket was scrubbed for technical reasons. The plan was to launch two days later after the problem was understood and resolved.
Nature had other plans.
On Sept. 17, a wildfire began burning on South Base, not far from Space Launch Complex 3E, where the Atlas V was poised to launch. This necessitated an indefinite delay to allow firefighters to remain in the area to put out the blaze.
After nearly a week of effort, the fire was finally contained, but not before it consumed more than 12,500 acres (5,058 hectares). It was the largest wildfire in Vandenberg’s history. No launch facilities were harmed, including nearby Space Launch Complex 4E, where SpaceX launches Falcon 9 rockets on polar-orbit missions. However, some power and communications infrastructure required a number of weeks to repair. What sparked the fire is still under investigation.
More recently, another week-long slip occurred this to ensure the launch readiness of the Atlas V.
WorldView-4 is a commercial Earth observation satellite. The spacecraft weighs 5,479 pounds (2,485 kilograms) and is 26 ft × 17 ft (7.9 m × 5.3 m). Its primary instrument is the GeoEye Imaging System-2, a 3.6-foot (1.1-meter) diameter telescope and will have a maximum resolution of about 12 inches (31 centimeters) – among the highest commercially available.
The WorldView-4 satellite will be placed in a Sun-synchronous orbit at an altitude of 383 miles (617 kilometers). Its 97-minute orbit will have a repeat interval of 3 days.
Having an estimated 7-year lifespan, WorldView-4 will join the growing DigitalGlobe constellation, which currently includes WorldView-1, GeoEye-1, WorldView-2, and WorldView-3.
The launch will be the ninth of 2016 for ULA and 112th since the founding of the company in 2006. It will also be the 65th launch of an Atlas V since the rocket started flying in 2002 and the 15th with a commercial payload.
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a blog about the International Space Station, called Orbital Velocity.