Just over nine months after losing its Dragon spacecraft during a cargo flight to the International Space Station, SpaceX is ready to set things right. On Wednesday, the company completed a successful static firing of its Falcon 9 rocket engines, and a test on Thursday found all systems ready for a Friday afternoon launch.
The resupply flight will carry 3,136 kg of cargo to the station in the Dragon capsule, including the 1,413 kg Bigelow Expandable Activity Module. And while there has been some excitement about the potential for expanding habitats in space, which could lead to much larger living quarters for human activity, much of the anticipation for Friday’s launch once again revolves around whether SpaceX will make a historic landing. on a drone ship at sea. The launch is scheduled for Friday at 4:43pm ET (9:43pm BST).
Speaking at a press conference on Thursday, Hans Koenigsmann, a senior launch official at SpaceX, said the company has learned from past efforts to gently land the Falcon 9 at sea. Nevertheless, the procedure remains a tricky one, as SpaceX attempts to land a 70-meter rocket stage in the middle of the ocean after flying into space at six times the speed of sound. “I really hope we’ll land well this time,” Koenigsmann admitted.
While it is easier to land a used rocket on the ground, where there is greater area and stability, perfecting landings at sea is better for performance. That’s because, from a propellant standpoint, it’s easier for a rocket to fly back to the ship below the point where it drops its payload into orbit, rather than going all the way back to a landing site near the coast of Earth. Florida.
For Friday’s resupply mission, the first stage of the Falcon 9 rocket, with its nine Merlin engines, would likely have enough fuel to make it all the way back to make a land landing, Koenigsmann said. However, the company’s next two or three flights, with their more dynamically challenging missions, will require nearly all of the rocket’s fuel to launch their payload into orbit. The first stages have a return by sea. As Friday’s flight profile is more benign, he said, it therefore presents “a good opportunity to fine-tune our drone landings, because in the long run we need to demonstrate that over and over again.”
So SpaceX will try to land on a drone ship again this time Of course I still love you, in the Atlantic Ocean off the coast of Florida. As the company, along with Blue Origin, seeks to fly missiles, land them vertically and reuse them, the ability to do this at sea is critical to reducing launch costs. Koenigsmann estimated that only about one-third to one-half of SpaceX flights on the Falcon 9 rocket will have enough fuel margin to return to land.
The company is also keeping a close eye on Friday’s launch, as it’s only the third flight of its upgraded Falcon 9 rocket. The rocket first flew in December 2015 and was redesigned so that unnecessary margin on the engines could be used to increase thrust by as much as 20 percent. The airframe and thrust structures were also strengthened to accommodate the additional thrust and increase the launch system’s reliability.
The upgraded Falcon 9 rocket also contains a new, densified mixture of liquid oxygen and kerosene fuel. This denser fuel allows SpaceX to put more propellant into the Falcon 9’s fuel tank, increasing the rocket’s performance by 5 or 6 percent, Koenigsmann said. “It’s a substantial improvement worth making,” he noted. However, working with the denser fuel is more challenging, as once charged it heats up quickly, allowing it to be kept in a vehicle for a limited amount of time before launching. These fuel problems caused several delays in the final launch of the upgraded Falcon 9 rocket, in March.
“When you first pad the rocket with this propellant, you learn things that you need to improve on,” he said. “I’m pretty sure we’ve learned most of it, but I can’t promise we’ve learned everything. I feel like we’ve got this issue relatively well under control at the moment.”
As SpaceX flies more with the upgraded version of its rocket, it hopes to fall into a more regular cadence of launches. Last month, the company’s president, Gwynne Shotwell, said SpaceX planned to launch 18 rockets this year. If the space station’s mission takes off on Friday, there will be only three for the year so far, a rate of less than one per month.
Koenigsmann acknowledged that SpaceX needs to step up the pace to meet the demands of its customers. “And we will pick up the pace,” he added. The company plans to do another launch at the end of April, and another one shortly after in May. As the company becomes more familiar with the upgraded Falcon hardware, he said, SpaceX aims to achieve a launch rate of once every two weeks by the end of 2016.