Falcon 9 V1.1 poised for launch.
The NASA / SpaceX-3 ressuply mission to the International Space Station is poised for a historic launch out of Cape Canaveral today. Standing on its transporter/erector at SLC-40 the rocket for today’s launch will be the first Falcon 9 v1.1 to launch to station, following three consecutive successful flights thus far.
Each of the previous SpaceX / NASA flights; COTS 1, COTS 2/3 and CRS missions 1 and 2 were boosted aboard the original Falcon 9 powered by Merlin 1-C engines. Consequently, this will be the first Falcon 9 V1.1 to fly without the 5.2 meter payload shroud.
Sitting atop the booster is an upgraded Dragon capsule, packed with nearly 5,000 lbs. of supplies, highlighted by four powered payloads in its pressurized section, and two powered payloads contained in the trunk, a first for SpaceX. This will also be the first flight for Dragon after several tense hours on the CRS-2 mission when a minute vendor change in pressurization valves caused three of the spacecraft’s four thruster pods to fail to come up to operating specifications. The problem was eventually resolved, and the rest of the mission proceeded flawlessly. Nevertheless, the Dragon team will no doubt be eager to see the spacecraft, now making its fifth flight overall, shake off those memories and register a somewhat less dramatic roundtrip to orbit.
Assuming a successful liftoff and trouble free flight, the spacecraft will berth with the station around 7:00am EDT on Wednesday April 16th. The most intriguing storyline around today’s launch however, may be what is not going to station, the Falcon 9 V1.1 first stage, equipped for the first time with retractable landing legs.
With “landing” for this attempt a section of the Atlantic ocean off the Georgia/South Carolina coast, the legs primary function will be to demonstrate successful deployment on a flight vehicle, and critically, provide aerodynamic stabilization on the way down, minimizing the stage’s tendency to rotate about its axis.
Speaking at a pre-launch press conference yesterday, SpaceX Vice-President of Mission Assurance Hans Koenigsmann estimated the chances of a successful recovery attempt at about 30-40%. Success in this case would be the booster achieving a three engine deceleration burn, followed by a stable descent controlled by the center mounted Merlon 1-D, coming to a stop just above the ocean surface, and then falling over into the water with engine cutoff.
Hoping for the best, SpaceX will have a recovery vessel in the area, and NASA will have air assets to photograph the descent. Even if the stage tank structure is destroyed, recovering the engines would be a major step forward for SpaceX, allowing for post flight analysis unavailable to any other current orbital launch vehicle.