Musk: Dragon Had Thruster Problem, But OK Now; Waiting for Data from Landing Leg Test

SpaceX Founder and Chief Designer Elon Musk said at a CRS-3 post-launch press conference today that the Dragon spacecraft had a problem with its Draco thrusters, but everything appears OK now.  Meanwhile, he is waiting for more data from the test of landing legs on the Falcon 9 first stage that took place over the ocean.  A heavy sea state dampened hopes that the stage itself would be recovered.

Speaking about two hours after the successful launch of this third SpaceX operational cargo mission to the International Space Station (ISS), Musk expressed happiness that the launch went as planned and did not seem worried about the thruster problem.  He said that an isolation valve that leads to the thruster pods did not respond so a backup valve was used instead.  Dragon has 18 Draco thrusters that are used to maneuver the spacecraft from its initial orbit to the ISS.  They are distributed across four pods: two pods hold four thrusters and two hold five thrusters.  An anomaly with the Draco thrusters caused a problem during the CRS-2 mission last year.  Musk was asked if today’s problem was related to last year’s and he said it was too early to tell.

As for the test of landing legs on the Falcon 9 first stage, Musk said he had seen data from the rocket stage’s descent down to Mach 1.1 and it looked good.  SpaceX planned to get data via aircraft and ship observations, but high seas prevented the ship from getting close to the stage as it reached the water.   Musk was not optimistic that the stage could be recovered and brought back for inspection because of the rough seas.  The data telemetered to the aircraft from the rocket stage, however, showed that it had a zero roll rate, which Musk considered a success in and of itself.   He remains hopeful that a stage can be recovered sometime this year and reflown next year.   He wants to make the Falcon 9 reusable.  Eventually the rocket stages would descend and return to a landing pad rather than being recovered at sea.

This launch was delayed several times for various reasons and the chances of launch today were low because of poor weather.  SpaceX’s competitor for NASA commercial cargo launches, Orbital Sciences Corp., has been working toward a May 6 launch of its Cygnus spacecraft on its second operational cargo mission to the ISS, dubbed Orb-2.   NASA indicated several days ago that if SpaceX CRS-3 launched today, it would delay Orb-2 until June 9.   NASA Associate Administrator for Human Exploration and Operations Bill Gerstenmaier said today that he would ask Orbital to continue planning for a May 6 launch until Dragon is successfully berthed to ISS on Sunday.   If that goes as planned, he will release the Orbital team and reschedule the launch for June.

Gerstenmaier said that NASA was planning to have a P-3 aircraft observe the descent of the Falcon 9 first stage today, too, but icing conditions prevented the aircraft from flying.  NASA wants data on the first stage’s supersonic thruster firings during descent because it is applicable to Mars entry-descent-and-landing.

SpaceX’s Hans Koenigsmann, Vice President for Mission Assurance, said that the company will attempt another landing leg test over the ocean on the next flight.  He also confirmed that the first flight of SpaceX’s Falcon Heavy rocket will take place from Kennedy Space Center, FL next year rather than from Vandenberg Air Force Base (VAFB), CA.  SpaceX President Gwynne Shotwell made the comment on Monday as she signed an agreement with NASA for a 20-year lease of Launch Complex 39A, the same Launch Complex once used for the space shuttle and Apollo flights to the Moon.

Shotwell’s statement on Monday was a surprise.  In 2011, the company announced it had broken ground on a new launch pad for Falcon Heavy at VAFB.  SpaceX has not yet flown a Falcon Heavy, which is being designed to take 53 metric tons (117,000 pounds) to low Earth orbit.  The company advertises it as  “the world’s most powerful rocket” that will be able to take twice as much mass into orbit as the Delta IV — currently the largest U.S. rocket — for one-third the cost.