After hard landing, Falcon 9 first stage back at Port Canaveral
CAPE CANAVERAL, Fla. — For the third time, a SpaceX Falcon 9 first stage returned to Port Canaveral via a drone ship after launching toward the heavens from Space Launch Complex 40 (SLC-40) five days prior. The booster landed at sea some 400 miles (644 kilometers) downrange less than 10 minutes after liftoff.
At about 11:30 a.m. EDT (15:30 GMT) on June 2, the Automated Spaceport Drone Ship (ASDS), also known as the Of Course I Still Love You, officially crossed into the port’s channel as it was towed toward the West Turning Basin. The drone ship and booster, on their journey home, were accompanied by three ships called Go Quest, Go Searcher, and Elsbeth III. The latter is the tugboat that regularly pulls the platform to and from the landing area.
It was pushed to the dock at 12:30 p.m. EDT (14:30 GMT), about an hour after entering the channel. What took less than 10 minutes by rocket, took over five days by drone ship. It technically arrived just on the other side of the horizon, from the perspective of Cape Canaveral, on May 31. However, for as-of-yet undisclosed reasons, the ASDS and accompanying ships loitered for over 24 hours before making the final leg of the trip.
This Falcon 9 first stage was used to launch Thaicom 8 at 5:39 p.m. EDT on May 27 (21:39 GMT). After pushing the second stage and payload at speeds reaching over 5,000 mph (8,000 km/h), the first and second stages separated.
As the second stage finished the job of placing Thaicom 8 into a parking orbit, the first stage rotated nearly 180 degrees to point its nine engines in the boosters direction of travel.
In a stunning sped-up video, the stage can be seen controlling itself via onboard thrusters and grid fins as it began to re-enter the atmosphere. Three engines fired for about 15 seconds to cushion the booster during its re-entry into the atmosphere. A few minutes later, those three engines ignited again in preparation for landing.
Like the last recovery attempt from a GTO mission (May 6), the first stage booster used three engines to slow the stage down much faster than on the first two landing attempts. This was done to minimize fuel loss due to gravity, as the remaining fuel for a recovery attempt was limited.
While the ASDS is technically a ship, its engines are only used to keep the drone ship at a fixed GPS location so that the booster can target and land on the 300-foot (91.4-meter) long deck.
After the rocket had landed, the three nearby ships pulled alongside the ASDS for maintenance crews to board and safe the booster. A tow line was then attached and the drone ship, with the recovered Falcon 9 first stage, was slowly brought back to port.
However, there was concern, upon landing, that the booster might tip over.
“Rocket landing speed was close to design max,” Elon Musk, SpaceX founder and CEO tweeted shortly after the landing to address viewer of the company’s launch webcast that noticed a slight wobbling of the stage.
Musk said that the stage was probably OK, but there was some risk of tipping. This was due to the fact that the contingency “crush core” was used up. He described on Twitter that the crush core was an aluminum honeycomb for energy absorption in the telescoping actuator.
Once the stage was within sight of land, it became clear that the booster had a noticeable lean to it, due to the aforementioned contingency crush core being used up. The ramifications of this are still unclear, but Musk’s tweet implied that the crush core is easily replaceable.
Now that the drone ship and booster are safely docked, the next step will be for a crane to attach a special cap at the top of the 140-foot (42-meter) tall rocket. This will allow for the whole stack to be lifted and moved to shore where it will be set on top of launch mounts, similar to those at SLC-40.
It will take up to a week for teams to first remove the landing legs, and then, carefully, with a second crane, lower the stage from a vertical to a horizontal position where it will be placed on a truck and shipped to the Horizontal Integration Facility (HIF) and Launch Complex-39A (LC-39A).
The company already has three recovered first stages inside the HIF just outside the perimeter fence of the old Space Shuttle launch pad. The first booster recovered is slated to be transported to SpaceX headquarters in Hawthorne, California, while the other two will be put through tests. This new stage will undergo similar qualification testing.
What those tests encompass is a bit unclear. Musk, at a press conference after the April 8 CRS-8 launch (which was the first mission to successfully land a booster out at sea), stated that the booster would likely be tested at LC-39A up to 10 times before being declared fit for reuse. No tests, however, have been performed yet.
The second booster to land at sea, on May 6, was also the first to return after a high-energy trajectory. That mission delivered the JCSAT-14 satellite to geostationary transfer orbit (GTO). Upon returning to port, just under a week later, it was clear that there were more scorch marks than on the previous two stages.
Musk, on Twitter, stated that the stage underwent maximum heating and would be their “life leader” for ground tests to ensure future stages will be capable re-launch.
The Thaicom 8 satellite was also delivered into GTO. Therefore, this current stage also underwent extreme heating. Additionally, as reported above, it touched down at near maximum speed survivable for the landing legs.
The first reuse of a Falcon 9 first stage is currently expected to take place sometime this year. According to a report by SpaceNews, SpaceX said that it was planning to meet with insurance underwriters in the next number of weeks to discuss the company’s plans for reuse certification.
Satellite company SES, of Luxembourg, has publicly stated that they want to be the first to launch a payload atop a used Falcon 9 first stage, but they would like a price discount of 50 percent. Other companies have also expressed an interest in launching a payload from a re-certified recovered booster.
The next mission for SpaceX’s Falcon 9 rocket is scheduled for June 16. It will launch the Eutelsat 117W B and ABS-2A satellites. This will be the second dual-GTO satellite launch that the company has carried out. Both spacecraft were constructed by The Boeing Company and will employ solar electric propulsion to circularize their orbits.
Additionally, the next launch with a subsequent landing at Landing Zone-1 at Cape Canaveral Air Force Station will be during the CRS-9 mission to resupply the International Space Station. That launch will also see a Dragon sent to the station with an International Docking Adapter in its trunk in advance of next year’s commercial crew activities.
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.