SpaceX’s Falcon 9 rocket soared into a near-perfect early-evening sky on May 27 at Cape Canaveral Air Force Station, lofting with it the Thaicom 8 communications satellite. Less than 10 minutes later, the first stage of the company’s booster successfully landed downrange on a drone ship—the third successful sea landing and fourth overall. The Falcon 9 “Full Thrust” rocket launched on time at 5:40 p.m. EDT (21:40 GMT) May 27 from Space Launch Complex 40 (SLC-40). This was the second launch attempt; the first one on the previous day was scrubbed due to a glitch with the motion of an upper stage engine actuator.
This was the NewSpace firm’s fifth launch this year, the second in the month of May. The company is beginning to ramp up its launch rate for as many as 11 flights remain on the manifest for this year—including the maiden flight of the huge Falcon Heavy.
Thaicom 8 was placed into a geostationary transfer orbit (GTO) and, using its own onboard engines, will gradually increase perigee to a make a circular 22,300-mile (35,888-kilometer) orbit above the equator. There, the spacecraft will provide TV and Internet services to India, Thailand, and parts of Africa. The satellite will reside at the 78.5 degrees East longitude and carry a Ku-band payload of 24 active transponders.
Orbital ATK was selected by Thaicom PLC to build the spacecraft, which has a mass of about 6,834 pounds (3,100 kilograms). It is based on the flight-proven GEOStar-2 satellite platform. Using two solar panels, the vehicle will be provided with at least 5.0 kilowatts of power and is expected to have an operational life of at least 15 years.
SpaceX began fueling the Falcon 9 rocket with super-chilled rocket-grade kerosene (RP-1) and liquid oxygen (LOX) about 35 minutes prior to launch. Unique only to the Falcon 9, the densified propellant allows more fuel to fit inside the tanks of the booster.
The fueling is now done in the lead-up to the launch to ensure that the RP-1 and LOX stay at the required temperature. Loading of all the propellant takes about 30 minutes.
At T–10 minutes, the 9 Merlin 1D engines that power the booster are also chilled prior to launch.
Two minutes before launch, the Range Control Officer verified the range was “go” for launch. Thirty seconds later, SpaceX’s Launch director gave the final “go” for launch.
One minute before taking to the skies, the flight computer began to do final prelaunch checks and the propellant tanks were pressurized.
All nine Merlin engines roared to life three seconds before launch and powered up to full strength before the launch latches finally let go of the 230-foot (70-meter) tall booster.
As it lifted into the early evening sky, the Falcon 9 began to turn toward its designated orbit. At about 1 minute and 17 seconds after launch, the rocket reached Max Q—the moment of peak stress on the rocket.
Everything continued as planned as the booster climbed higher and faster. About two minutes and 35 seconds after leaving Cape Canaveral, the first stage’s engines cutoff as planned. Three seconds later, the first and second stages separated.
The second stage’s Merlin Vacuum engine successfully ignited and continued to push the stage and its precious payload toward orbit. Just over 30 seconds later, the launch fairing—protecting Thaicom 8 from the denser part of the atmosphere—jettisoned as it was no longer needed. Falcon 9’s second stage continued to burn for just over six minutes before cutoff, as planned.
As all that was happening, the first stage, in what has become a normal practice for SpaceX, turned around and prepared for re-entry into the atmosphere and subsequent recovery on the Of Course I Still Love You drone ship some 400 miles downrange of Cape Canaveral.
As this was a GTO mission, there was very little fuel spared for recovery. As with the previous landing, the first stage re-entered the atmosphere much faster than it would have done had it been part of a low-Earth orbit launch. Once the stage hit the atmosphere, it fired three of its engines to help cushion the rocket from some of the heating effects of re-entry.
Nearly nine minutes after leaving the pad, the first stage announced its presence to the drone ship with a signature triple sonic boom. Moments later, three of the booster’s nine engines ignited to slow it down extremely fast in what is called a hover slam. A few seconds before touching down, the two side engines shut down, leaving only the center engine firing for the final seconds.
|The first stage of the Falcon 9 rocket almost in the center of the drone ship some 400 miles downrange in the Atlantic Ocean. Photo Credit: SpaceX|
After the smoke dispersed, the video feed showed that the company had recovered another booster on a GTO mission profile. However, the booster seemed to have a bit of a wobble. This was later confirmed on Twitter by company founder and CEO Elon Musk.
“Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion,” Musk tweeted.
Musk said the stage would probably be OK, but there is some risk of the stage tipping before returning to Port Canaveral. He said “crush core” is aluminum honeycomb absorption in the telescoping actuator on the landing legs.
“Easy to fix (if Falcon makes it back to port),” Musk tweeted.
Over the next few days, the booster will be safed and inspected by SpaceX engineers out at sea before towing the drone ship back to Port Canaveral to offload and transport it to, likely, the company’s Horizontal Integrated Hangar at Launch Complex 39A. There are already three recovered boosters being housed there. It can hold a maximum of five. The first booster was recovered after it landed on land back in December 2015.
Meanwhile, just over 27 minutes after launch, the second stage, now in orbit, restarted to push Thaicom 8 into GTO. The burn lasted about a minute. Four minutes later, Thaicom 8 was deployed successfully.
Thursday’s launch was the 25th time that a Falcon 9 was launched, either from SLC-40 or Vandenberg Air Force Base’s SLC-4 East in California. It came less than three weeks after the last launch which delivered JCSAT-14 to GTO.
The rocket is capable of lifting about 50,256 pounds (22,800 kilograms) to LEO and 18,300 pounds (8,300 kilograms) to GTO. Recently, the company detailed how much payload the rocket could send to Mars—8,860 pounds (4,020 kilograms). The company is working on developing a version of its Crew Dragon to send to the surface of Mars as early as 2018.
The next launch of a Falcon 9 is expected to occur at 10:30 a.m. EDT (14:30 GMT) June 16. The booster will send the Eutelsat 117 West B and ABS 2A satellites to GTO. Additionally, the next Dragon cargo ship flight to the International Space Station, CRS-9, has been scheduled for July 16. The company hopes to recover the first stage of the rocket at Landing Zone 1 during the CRS-9 launch.
Written by: Derek Richardson
Original source: spaceflightinsider.com