Last-minute SpaceX, NASA astronaut launch to International Space Station cancelled.

(CNN) ⸻ SpaceX and NASA have called off an astronaut launch to the International Space Station due to an issue with the rocket's ground system. The launch was called off due to a problem related to the TEA-TEB ignition fluid, which is used to ignite the SpaceX Falcon 9's rocket engines at liftoff. The four astronauts, who were strapped into their Crew Dragon capsule atop the rocket in the hours leading up to launch, waited for the rocket to be drained of its fuel before beginning the process of disembarking from the spacecraft and 230-foot-tall (70-meter) rocket. They will stay on site at Kennedy Space Center until the next launch attempt. Additional back-up launch opportunities are available beginning on March 2. The SpaceX Falcon 9 rocket and Crew Dragon capsule were scheduled to launch from NASA's Kennedy Space Center in Cape Canaveral, Florida, at 1:45 a.m. ET Monday. This mission is expected to mark the seventh astronaut flight SpaceX has carried out on NASA's behalf since 2020. The Crew-6 team includes NASA astronauts Stephen Bowen, Warren Hoburg, Sultan Alneyadi, and Russian cosmonaut Andrey Fedyaev. They are expected to spend up to six months on board the ISS, carrying out science experiments and maintaining the two-decade-old station. The mission comes as the astronauts currently on the ISS have been grappling with a separate transportation issue. In December, a Russian Soyuz spacecraft that had been used to transport two cosmonauts and one NASA astronaut to the space station sprang a coolant leak. Russia's space agency, Roscosmos, launched a replacement vehicle on February 23 and it arrived at the ISS on Saturday.