For the second time this week Space Exploration Technologies (SpaceX) has postponed the first launch of its Falcon 9 v1.1 to geosynchronous transfer orbit from Cape Canaveral AFS, Fla., this time due to a slow ramp-up in thrust on the rocket’s nine first-stage engines.

The Nov. 28 mission was expected to carry the Orbital Sciences Corp.-built SES-8 satellite to a geosynchronous transfer orbit of 295 km x 80,000 km altitude and an inclination of 20.75 deg. for Luxembourg-based SES, the world’s second largest commercial fleet operator by revenue.

At T-0 seconds into the launch sequence, however, the Falcon 9 flight computer aborted the mission after igniting all nine of the rocket’s nine Merlin 1D engines. The abort, which was called at the beginning of a 65-minute launch window beginning at 5:39 p.m. EST, was due to a slower-than-expected ramp up in thrust, according to Falcon 9 Product Manager John Insprucker.

After sifting through data from the aborted launch attempt, mission managers set a new launch target of 6:44 p.m. At 6:28 p.m., Insprucker said SpaceX had “made some modifications in the ground systems” and was ready for another launch attempt. At T-48 seconds, however, mission managers aborted the recycled launch attempt, postponing the mission for several days to review data from the first stage engines.

“The expectation is we will detank the rocket, bring it horizontal, most likely bring it back into the hangar, do some inspections, determine the path forward and then be ready to attempt another launch probably within a few days,” Insprucker said.

The delay follows a Nov. 25 launch attempt that was scrubbed owing to pressure fluctuations on the Falcon 9’s first stage liquid oxygen tank, after which the Falcon 9’s first and second stages were detanked and the rocket was rolled back to the hangar. Insprucker said “everything looked good” and tat mission managers addressed the pressurization issue by modifying the countdown sequence for topping off the rocket’s oxygen tank.