SpaceX is preparing for nine-hour launches on Sunday, the shortest interval between two flights in orbit in Florida since 1966. The launches are a dramatic effort to put another 60 Starlink Internet stations into orbit, followed by an Argentine satellite on remote sensing.
Planned releases follow the heels andUnited Launch Alliance Delta 4 Heavy rockets at Cape Canaveral Air Force Station early Saturday, which grounded a National Intelligence Agency’s classified spy satellite.
At least one of the three engines of the first stage of the Delta 4 heavy lifting platform was in the process of ignition, when the computers ordered a shutdown just three seconds before the scheduled start. It is not clear what caused the interruption, but the flight will be delayed for at least a week until inspections and corrective action are taken.
SpaceX has already received permission from the Federal Aviation Administration and the Eastern Air Force to attempt mutual launches on Sunday.
However, the weather could play a role in the historic double header, with forecasters demanding a 50-50 probability of acceptable weather for Starlink’s morning launch, with the Argentine satellite SAOCOM 1B “dropping” to 40 percent in the evening.
If the weather cooperates, Starlink will take off from pad 39A at Kennedy Space Center at 10:12 ET. It will be the 100th flight of SpaceX since Falcon 1 was first launched in 2006 and the 94th flight of its Falcon 9 draft horse. Three Falcon Heavies tri-core aircraft have also been launched.
The 60-star line to be launched on Sunday will raise the SpaceX constellation to 713. The first stage of the rocket, which makes its second flight, will attempt to land in the drone without lowering the vehicle from the lower atmosphere.
Nine hours and six minutes after Sunday morning’s launch, another Falcon 9 aircraft is scheduled to take off from Pad 40 at nearby Cape Canaveral Air Station to orbit SAOCOM 1B, the first such flight from Florida since 1969.
The first stage of the Falcon 9, which takes place in the fourth, will attempt to land back at Cape Canaveral Air Force Station. If Starlink and SAOCOM landings are successful, SpaceX’s record will be 60 renewed in the first phase, 18 at the Air Force Station, 40 at the droneships and two at Vandenberg Air Force Base in California.
To get into polar orbit from Cape Canaveral, Falcon 9 launches on a southern trajectory and then performs a “dogleg” maneuver that once escapes the Florida coast and bends the trajectory more directly to the south. The flight path will carry a rocket over Cuba.
In 1960, allegedly falling remnants of a broken rocket killed a cow in Cuba, sparking protests in the island nation. All polar orbit missions since 1969 have been launched from Vandenberg, where the missiles remain over the Pacific Ocean until they orbit.
SpaceX originally planned to launch SAOCOM 1B from Vandenberg, but requested permission to relocate to Cape Canaveral to alleviate ground handling problems.
The company probably obtained government permission to do so in part because of a dogleg maneuver that minimizes overflights of populated areas, high rocket altitude by the time it reaches populated areas further down, and because the Falcon 9 is equipped with an automatic flight safety system. AFTS is designed to end a flight quickly if an impending catastrophic problem is identified.
Weighing 6,720 pounds, the SAOCOM 1B requires a polar orbit to allow radars penetrating the clouds to observe the entire planet as it rotates downward. The spacecraft will operate in accordance with an identical L-band radar mappertogether with the Italian X-band COSMO-SkyMed satellites.
The $ 600 million SOACOM system, which is to be directed into a 360-kilometer orbit, is designed to monitor soil moisture and a range of other factors affecting the agricultural sector. High-resolution data collection throughout the day, regardless of cloud cover.
“One of the main goals of SAOCOM satellites is to provide information for the agricultural sector,” Raúl Kulichevsky, executive and technical director of the Argentine space agency CONAE, told Spaceflight Now.
“One of the things we develop is soil moisture maps, not just the surface, but using L-band capabilities, we can measure soil moisture 1 meter below the earth’s surface. So that’s very important information.”