A SpaceX Falcon 9 will make another attempt Sunday to launch 24 satellites for Amazon’s Project Kuiper internet service after three earlier attempts were scrubbed.
Liftoff from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida is scheduled for 8:57 a.m. EDT (12:57 UTC). Sunday’s launch window closes 27 minutes later. Spaceflight Now will have live coverage beginning about an hour prior to liftoff.
The 45th Weather Squadron, based at Cape Canaveral, gave the mission a 55 percent chance of acceptable weather for launch. The primary concerns in the forecast issued Saturday were for violations of the cumulus cloud, anvil cloud and lightning rules.
This will be the fourth scheduled launch attempt for the mission, designated KF-02. During the first countdown on Thursday, SpaceX stopped the clock prior to the start of fueling and later said on social media it had delayed the launch a day to allow for “additional vehicle checkouts.”
The Falcon 9 was lowered into the horizontal position at pad 40, presumably to work on a technical problem with the rocket. Then, just a few hours before the planned T-0 on Friday, the company announced the launch was called off and rescheduled for Saturday.
For Saturday’s launch attempt, the 45th Weather Squadron was forecasting only a 40 percent chance for favorable weather but offered some hope that rain clouds would stay offshore. However, it was not to be. The countdown was halted by the launch director with 28 seconds left on the clock, as heavy rain started to fall at the pad.
The booster for the KF-02 mission is a converted Falcon Heavy core stage that is flying for the first time. In a May 7 social media post, Jon Edwards, SpaceX vice president of Falcon and Dragon, said that B1091 will be used as a Falcon 9 booster “a handful of times before being reconfigured and flying as a Falcon Heavy” center booster.
If weather permits, the Falcon 9 will liftoff on a north-easterly trajectory, and the first-stage booster will target a landing on SpaceX’s drone ship ‘A Shortfall of Gravitas’ a little more than eight minutes later. If successful, this will be the 120th booster landing on this vessel and the 486th booster landing to date.
About eight and a half minutes into flight, Falcon 9’s second stage will place the Kuiper satellites into an initial parking orbit, before making a short three-second burn almost 53 minutes into flight to circularize the orbit. The approximately seven-minute satellite deployment sequence begins at T+56 minutes, 18 seconds.
