Orbital ATK’s unmanned Cygnus spacecraft is set to embark upon its return-to-flight mission tonight (Dec. 3), carrying more than 7,700 lbs. (3500 kilograms) of research materials, crew supplies and hardware for the International Space Station — and you can watch the liftoff live.
The Cygnus is scheduled to launch at 5:55 p.m. EST (2255 GMT) from Cape Canaveral Air Force Station in Florida aboard a United Launch Alliance Atlas V rocket, in the first liftoff for the freighter since Orbital’s Antares rocket exploded during a cargo delivery last October. (Cygnus will fly atop an Atlas V until a revamped version of Antares is ready to go.) The launch will initiate the fourth of eight resupply missions Orbital ATK is flying under a $1.9 billion contract with NASA. The live webcast of the OA-4 mission will begin at 4:30 p.m. EST (2130 GMT), and you can watch it here at Space.com, courtesy of NASA TV.
As of this morning, there’s a 60 percent chance that weather conditions will be favorable for the launch, U.S. Air Force officials reported. If the launch occurs on schedule, the spacecraft will reach the space station Sunday, Dec. 6, where NASA astronaut Kjell Lindgren will take point on capturing it via the station’s Canadarm2 robotic arm, assisted by NASA astronaut Scott Kelly. If weather conditions worsen, the team will attempt to launch again tomorrow (Dec. 4) for a Dec. 7 or Dec. 8 arrival.
Even though the Orbital ATK Cygnus freighter is on top of an ULA Atlas V rocket, this is an important flight for the Commercial Resupply Program.
SpaceX and the Russian Progress plan return to launches within thirty days.
The launch attempt was scrubbed before the window was officially closed due to deteriorating weather conditions. This is unusual, but not entirely expected when the probability of Go-for-Launch conditions dropped from 40% to 30% down to 10% throughout the day.
The next launch window opens at 5:33pm ET tomorrow, again lasting for 30 minutes. The weather forecast remains grim, with only a 30% chance of acceptable conditions. If it also gets scrubbed, the mission has additional windows on December 5th and 6th before mission planners need to get creative.
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