Weather could stand in way of Falcon 9 launch Saturday

File photo of a Falcon 9 rocket inside a SpaceX hangar at Cape Canaveral. Credit: SpaceX

Rainy weather expected across Central Florida this weekend has a 50-50 chance of preventing the launch of a SpaceX Falcon 9 rocket Saturday on a resupply mission to the International Space Station, U.S. Air Force forecasters said Wednesday.

The official weather outlook issued by the Air Force’s 45th Weather Squadron calls for thick clouds and isolated rain showers at Cape Canaveral during Saturday’s launch countdown.

Liftoff is timed for 10:01 a.m. EST (1501 GMT), roughly the moment the space station’s orbital path is positioned above Florida’s Space Coast.

But meteorologists are tracking a upper-level trough expected to strengthen over the Gulf of Mexico on Friday.

“On Saturday, this upper-level trough will migrate east, bringing the clouds and rain over the Florida peninsula,” the Air Force weather team wrote in Wednesday’s forecast. “The clouds and rain will gradually increase through the countdown and be entrenched over the spaceport by midday. The primary weather concern for launch Saturday is the thick cloud cover and rain showers associated with the upper-level trough.”

There is a 50 percent chance the weather conditions will violate one of the Falcon 9’s launch rules.

The outlook calls for mostly cloudy skies, isolated rain showers, southeast winds of 10 to 15 mph, and a temperature of 70 degrees Fahrenheit.

If the launch is delayed to Sunday, the weather should improve, with a 70 percent chance of acceptable conditions.

“On Sunday, the cloudiness and rain associated with the upper-level trough will continue to slowly move east, diminishing through the countdown,” forecasters wrote. “The main weather concern will be cumulus clouds associated with lingering instability.”

The 213-foot-tall Falcon 9 rocket will take off from launch pad 39A at NASA’s Kennedy Space Center, a complex just inland from the beach originally constructed for Saturn 5 moon rockets in the 1960s and modified in the late 1970s to support space shuttle flights.

SpaceX signed a 20-year lease for the launch pad in 2014, and the company has temporarily transferred all of its Florida launches to pad 39A while workers repair damage to nearby pad 40 after a rocket exploded there in September.

Crews finished modifications and testing of the historic Apollo-era launch pad with a fueling and hotfire test of the Falcon 9’s first stage engines Sunday. The successful test verified the new RP-1 and liquid oxygen fueling system installed by SpaceX at pad 39A.

Technicians rolled the rocket back inside SpaceX’s hangar at the southern perimeter of the launch facility for attachment of the Dragon cargo capsule loaded with supplies for the space station and its six-person crew, including a lightning imager and an instrument to monitor the health of the atmosphere’s ozone layer.

The Dragon supply ship will carry 5,266 pounds (2,389 kilograms) of cargo on SpaceX’s 10th logistics launch to the orbiting research outpost. If the mission takes off as scheduled Saturday, the cargo carrier will reach the space station Monday, with grapple by the robotic arm expected around 9 a.m. EST (1400 GMT).

SpaceX has two cargo transportation contracts with NASA for at least 26 space station supply shipments through 2024.

The rocket is expected to return to the pad this week, riding a new transporter-erector that will hoist the Falcon 9 vertical on the launch mount over the flame trench.

After liftoff, the Falcon 9’s first stage will return to Cape Canaveral from the edge of space, targeting a rocket-assisted vertical touchdown at SpaceX’s Landing Zone 1 about 9 miles (15 kilometers) south of pad 39A. The recovery would mark the third time a Falcon 9 booster stage has landed at Cape Canaveral, and the first time in daylight.

Final regulatory approval for the launch and landing from the Federal Aviation Administration is still pending.

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