Update 11:15 a.m. ET: SpaceX Cancel the mission for today, and we’ll try again tomorrow during a three-hour launch window that opens at 9 a.m. EST. There was an unusually high pressure reading in the upper stage liquid oxygen tank which the company will be working to resolve.

SpaceX today launches Falcon 9 from the Kennedy Space Center, with a launch window that spans three hours and opens at 9 a.m. EDT (6 a.m. PDT). The mission will carry a spy satellite for the US National Reconnaissance Office (NRO) and will include a retrieval attempt for the enhanced Stage 1 vehicle used on the Falcon 9.

The first stage of the Falcon 9 has already been flown four times previously, including during two of SpaceX’s commercial resupply missions to the NASA International Space Station, and during the launch of Starlink, as well as SAOCOM 1B, the operation of the launch of a satellite to the Argentine space agency in August .

SpaceX will attempt to land again at its landing pad at the Cape Canaveral Space Force Station, which is a rare occurrence for its use of two unmanned aircraft landing craft stationed in the ocean. SpaceX’s sea landings were introduced to allow missile boosters that did not have enough fuel remaining on board to bring them back to Earth – meaning these NRO mission parameters allow for a “return to dispatcher” flight back home.

Usually, when there is a longer launch window, SpaceX aims to launch at first, depending on weather conditions. If that is the case today, the above broadcast should start around 8:45 AM EST (15 minutes before the window opens).