Today, the United Launch Alliance is set to launch one of its Delta IV rockets — the bigger sibling to the company’s more prolific Atlas V. The vehicle is tasked with carrying a communication satellite into a super high orbit for the US Air Force.
The Boeing-built satellite is the eighth of the military’s Wideband Global SATCOM constellation — a series of probes that together provide extremely high-bandwidth communication. In order to provide this capability, today’s satellite, called WS-8, is meant to orbit 22,000 miles above the Earth’s equator.
Getting to a high orbit requires some extra power, though today’s Delta IV rocket isn’t the most powerful version of the vehicle that ULA has. That would be the Delta IV Heavy, which sports three core boosters to help lift the heaviest payloads into space. The one that’s launching this afternoon is a special configuration of Delta IV, in which four smaller motors are strapped to the rocket’s base to give some extra thrust. It’s only the sixth time this version of the rocket has flown, and it may not have many more launches in the future. ULA plans to phase out all versions of the Delta IV, except for the Heavy variant, by 2018.
Takeoff of the Delta IV is scheduled for 6:53PM ET from Cape Canaveral, Florida. ULA has a 49-minute launch window, though, so the vehicle can liftoff anytime up until 7:42PM ET. So far, there’s an 80 percent chance of favorable weather conditions. If for some reason the launch doesn’t happen today, ULA has the option of trying again tomorrow, though weather doesn’t look as good.
Today’s launch could be the first of a series of launches over the next week and a half in the US. One of Orbital ATK’s Pegasus XL rockets, which are launched from the belly of an airplane, is set to take off from the Cape on December 12th, delivering a NASA hurricane-monitoring satellite into orbit. And on December 16th, ULA is scheduled to launch a commercial communication satellite from Florida, though that one will be on an Atlas V. That same day, SpaceX is aiming to launch a series of satellites for Iridium from Vandenberg Air Force Base in California. If successful, it will mark the first time the company launches its Falcon 9 rocket after one of its vehicles exploded in September. However, there’s been no official confirmation that the launch is happening yet, so it’s unclear if SpaceX will fly the Falcon 9 again before the end of the year.