SpaceX is sorting through a first-stage Falcon 9 engine anomaly that occurred when the two-stage booster lifted off for the International Space Station on Oct. 7 under a $1.6 billion NASA Commercial Resupply Services contract that signals the restoration of U.S. cargo delivery and return capabilities lost with the space shuttle’s 2011 retirement.

Engine No. 1 experienced a sudden pressure loss without an explosion that led to a shutdown command about 79 sec. into the nearly 10-min. ascent to orbit, according to an Oct. 8 statement from Katherine Nelson, the Hawthorne, Calif., based company’s vice president for marketing and communications.

The Dragon capsule — carrying a nearly 1,000-lb. multinational cargo of food, clothing and research gear — reached its initial target orbit despite the engine failure, via an extended propulsion system burn. The capsule was on course to reach the orbiting science laboratory early Oct. 10, as scheduled.

“Initial data suggests that one of the rocket’s nine Merlin engines, Engine 1, lost pressure suddenly and an engine shutdown command was issued immediately. We know the engine did not explode, because we continued to receive data from it,” according to the SpaceX statement. “Our review indicates that the fairing that protects the engine from aerodynamic loads ruptured due to the engine pressure release, and that none of Falcon 9’s other eight engines were impacted by this event.”

The incident occurred as the spacecraft was achieving supersonic velocity and rising through Max Q, the point of maximum dynamic pressure, according to the mission timeline.

The Falcon 9 performed as designed to achieve orbit with an engine loss, said SpaceX President Gwynne Shotwell, who first addressed the incident in a post-launch news briefing with NASA Administrator Charles Bolden.

“We will continue to review all flight data in order to understand the cause of the anomaly, and will devote the resources necessary to identify the problem and apply those lessons to future flights,” according to the follow-up SpaceX statement.

In spite of the difficulty, Bolden appeared pleased with the CRS-1 mission start and those who question a greater commercial role in NASA operations.

“This was a critical event for NASA and the nation tonight,” the administrator said moments after the Falcon 9/Dragon lifted off from Cape Canaveral on Oct. 7 at 8:35 p.m., EDT. “Just a year after the retirement of the space shuttle, we have returned space station resupply missions to U.S. soil.”