Thursday, October 12, 2017

SpaceX Notches 15th Falcon 9 Launch in 2017 with SES-11 Mission

SpaceX launches the SES-11/EchoStar-105 satellite. Photo Credit: Vikash Mahadeo / SpaceFlight Insider

Hot on the heels of a Falcon 9 launch on the West Coast, SpaceX sent its 15th rocket into space in 2017. The SES-11/EchoStar-105 mission came less than 60 hours after the NewSpace company sent 10 Iridium NEXT satellites into orbit. Liftoff occurred at 6:53 p.m. EDT (22:53 GMT) Oct. 11, 2017, from Launch Complex 39A.

“Partnering with the commercial space industry demonstrates just one of the many ways the United States Air Force is a multi-domain service in land, air, sea, space and cyberspace,” the 45th Space Wing, which supports Eastern Range launches in Florida, said in a statement on Facebook. “It’s a great privilege to work with this incredible team on the Space Coast and execute another flawless mission.”

This launch was the third to use a “flight-proven” first stage and the second time that Luxembourg-based SES has utilized used hardware to loft one of its satellites into space. The other was the SES-10 mission, which occurred in March 2017 and was the first Falcon 9 to utilize a recovered and refurbished first stage.

The first stage core for the Oct. 11 launch, core 1031, was previously flown on during the CRS-10 space station resupply flight in February 2017.

SES-11 is the next in a series of satellites by SES that are intended to accelerate the roll-out of high and ultra-high definition video services to North America. Manufactured by Airbus Defence and Space, SES-11/EchoStar-105 utilizes the Airbus Eurostar E3000 platform to serve as the core for the hybrid satellite. SES-11/EchoStar-105 serves as a dual-mission satellite for U.S.-based EchoStar and SES.

Weather conditions for this partly cloudy sunset launch were about as good as could be asked for since the probability of conditions violating launch were at 10 percent. The only concerns were cumulus clouds.

The countdown proceeded smoothly with no issues reported. At about 70 minutes before the planned liftoff, rocket grade kerosene, known as RP-1, began flowing into the first and second stage tanks. About 45 minutes later, liquid oxygen also began flowing into the rocket.

Some seven minutes before the ignition of the nine first-stage Merlin 1D engines, they began to chill to be conditioned for launch. Three seconds before liftoff, all nine roared to life to produce more than 1.7 million pounds-force (7,600 kilonewtons) of thrust.

After the launch restraints were released and the 230-foot (70-meter) tall Falcon 9 lifted off, it began a series of pitch and roll maneuvers as it set course for the final destination of SES-11 – a geostationary orbit at the 105 degrees West orbital slot. However, first, the vehicle had to deploy the satellite into a geostationary transfer orbit (GTO).

The Falcon 9 experienced maximum dynamic pressure, the point where atmospheric stresses on the vehicle were the highest, at about 1 minute, 10 seconds into its flight. Following the shutdown of the first stage at 2 minutes, 35 seconds, stage separation occurred. Once it moved sufficiently away from the first stage, the single Merlin vacuum engine took over to continue boosting SES-11 into an initial low-Earth parking orbit.

Following a parabolic trajectory, the flight-proven first stage performed an entry burn at about 6 minutes 24 seconds to cushion its re-entry into Earth’s atmosphere. Core 1031 began its landing burn several minutes later to softly touch down on the Autonomous Spaceport Drone Ship named Of Course I Still Love You. The landing took place at about 8 minutes 33 seconds after departing from Florida.

Meanwhile, after the first stage finished making its way to low-Earth orbit at 8 minutes, 38 seconds, the second stage engine cut off as expected. The vehicle then coasted for about 18 minutes before relighting its engine for one minute to push the spacecraft into a GTO.

At 36 minutes after leaving Florida, the SES-11/EchoStar-105 satellite was deployed. It will spend the next days and weeks using onboard engines to circularize its orbit into a geostationary one provide Ku- and C-band coverage across North America, including Mexico, Hawaii, and the Caribbean.

The Oct. 11 launch was the 43rd Falcon 9 flight since the rocket design began flying in 2010. It was the 11th to fly out of Launch Complex 39A. Up to five more missions are planned by SpaceX before year’s end, with the next flight expected in late October carrying Koreasat 5A into orbit for KT Corporation.

Written by: Paul Knightly
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