SpaceX‘s rescheduled Nov. 25 launch on Nov. 28 was rescheduled yet again due to a slow rocket thrust buildup. The Thanksgiving Day launch was ready to go and seconds from liftoff, but the on-board computer automatically aborted the sequence. SpaceX (and Tesla) CEO Elon Musk announced the event on Twitter — and shared a few technical details explaining the failure.
The countdown was reset by increasing the helium spin start pressure to loosen the computer abort parameters. But the SpaceX team manually aborted to be on the safe side. Inspections ensued.
Musk’s launch day tweets were as follows:
Launch aborted by autosequence due to slower than expected thrust ramp. Seems ok on closer inspection. Cycling countdown.
Increasing helium spin start pressure. Probably <50% chance of passing all aborts, but worth a try. Countdown resuming …
If launch aborts, we will bring the rocket down for engine inspection, so probably a few days before next attempt
We called manual abort. Better to be paranoid and wrong. Bringing rocket down to borescope engines …
To “borescope” means to inspect the engines. The team then spent a day cleaning the gas generators. After inspections concluded, the team discovered that the auto-abort was caused by oxygen in the ignition fuel. Saturday’s tweets from Musk:
Rocket engines are healthy, but cleaning turbopump gas generators will take another day. Aiming for Mon eve launch.
Abort was caused by oxygen in ground side TEA-TEB. Upper stage on separate internal circuit, so doesn’t face same risk.
As long as all further inspections and adjustments pan out, it looks like the launch will happen on Monday. If it is successful, the Falcon 9 rocket will place a SES-8 telecommunications satellite into orbit 50,000 miles above the Earth, according to Spaceflight Now.
SOURCE: Spaceflight Now