NASA
Two minutes before SpaceX’s Falcon 9 rocket was scheduled to launch a crew of four astronauts to the International Space Station early Monday, the mission was scrubbed due to an ignition fluid issue.
NASA’s Crew-6 mission was scheduled to take off at 1:45 a.m. from Launch Complex 39-A at Kennedy Space Center, Florida. During a space agency webcast, the host first mentioned the TEA-TEB igniter problem about five minutes before the expected liftoff time. The mission’s operators were unable to resolve technical issues before the immediate launch window opened.
The crew was safe aboard the Crew Dragon spacecraft. NASA astronauts Steven Bowen (mission commander) and Warren “Woody” Horberg (its pilot) are mission experts United Arab Emirates Along with Federation cosmonaut Sultan Arneyadi and Roscosmos cosmonaut Andrei Fedyaev step out of the vehicle after propellant was turned off late Monday morning. Loaded from a rocket.
The mission will have an early backup opportunity on Tuesday, February 28th. But while the weather was ideal on Monday morning, that may not be the case on Tuesday. The launch site should be in good condition, but forecasters are concerned about the weather along the rocket’s path. This could have implications if an abort occurs during launch, requiring the Crew Dragon to make an emergency return to Earth. NASA and SpaceX will also have the opportunity to launch Crew Dragon missions on March 2nd, 3rd and 4th.
Immediately after scrubbing SpaceX tweeted A little more information on the cause: “Due to a problem with the TEA-TEB ground system, we are canceling tonight’s Crew-6 launch,” the company said.
TEA-TEB is a combination of triethylaluminum (TEA) and triethylborane (TEB). Basically, these are two different metallic elements each bonded to three hydrocarbon atoms. These molecules are held together by fairly tenuous bonds that are easily broken. Therefore, TEA-TEB ignites spontaneously when in contact with oxygen.
This is useful for igniting rocket engines, but this can get pretty tricky, at least when it comes to starting the engine in a precisely controlled manner at specific times.The Merlin 1D engine inside the Falcon 9 , oxygen is pumped into the engine’s combustion chamber to satisfy the TEA-TEB. After combustion begins, kerosene is injected into the chamber and the TEA-TEB ignition fuel flow is turned off. Then increase the flow of oxygen and kerosene to increase thrust.
During the early stages of development of the Falcon 1 and Falcon 9 rockets, SpaceX struggled a lot to safely handle the TEA-TEB and fire the Merlin engines when needed. “The best thing about TEA-TEB is that it ignites when exposed to air,” said Tim Buza, SpaceX’s original launch director. “The worst thing about TEA-TEB is that it ignites when exposed to air.”
Given the hazards involved in working with chemicals, SpaceX may have made the right decision to cancel Monday morning’s launch.
