Launching the same rocket to orbit twice in 24 hours has never been done before. But Elon Musk says the newest version of his Falcon 9 rocket will accomplish the feat in 2019.
“This is a ridiculously hard thing that has taken us…16 years of extreme effort and many, many iterations,” the serial entrepreneur told reporters, after warning them “we’re definitely going to stay on space, don’t even try.” SpaceX is debuting the new rocket today with the launch of Bangladesh’s first satellite.
Musk said this is intended to be the final version of the SpaceX workhorse Falcon 9, allowing his engineers to focus on a larger interplanetary rocket called the BFR. In the meantime, Block 5, as the final iteration is known, could fly as many as 300 missions into space. “If things go well, SpaceX will launch more rockets than any other country in 2018,” Musk predicted.
Key to that goal is the ability to simply re-fuel the reusable rocket between flights, with no scheduled maintenance needed. The current version of the rocket requires at least 10 days of refurbishment between flights, on “hundreds of little things that need to be made more robust,” Musk said.
Post launch, Musk said his team will be “taking this rocket apart and confirming our design assumptions to be confident that it is indeed able to be reused without taking it apart. We need to take it apart to confirm it doesn’t need to be taken apart.”
The reusability project is designed to drive down the cost of the rocket. Per Musk, building a recoverable first stage represents about 60% of the cost of a launch, with the expendable upper stage and carbon fiber nosecone accounting for another 30%, plus 10% for the operations of the launch itself.
Despite the Block 5 being the final version of the rocket, Musk noted that further modifications could add reusability to the upper stage and nosecone, called a fairing.
Musk predicting that marginal cost of launching a Falcon 9 falling to as low as $5 million in the years ahead, though customers would pay more to amortize the development of the rocket. Currently, a “flight-proven” rocket retails for about $50 million, making it the most affordable orbital rocket on the global market.
Besides reusability, the rocket also contains “probably the most advanced pressure vessel ever developed by humanity,” Musk said. SpaceX crams super-chilled propellant into composite tanks lined with aluminum, but after a fueling accident destroyed a rocket in 2016, NASA asked the company to re-design the plumbing.
Now, the burst pressure of the vessels “is more than twice what they are actually loaded to on the pad,” Musk said. “We have tested the living daylights out of those things, 17 ways till Sunday.”
Musk conceded that NASA concerns led the company to develop a contingency plan to use a different kind of vessel to hold the pressurized gases needed to operate the rocket, but didn’t think it would be necessary. Noting recent public criticisms of the system by Boeing vice president John Mulholland, a rival in the space transportation business, Musk said, “Obviously our competitors are going to make hay of this. I really do not think this presents a safety issue for astronauts…[and if necessary,] we can adjust our operational procedures to load the propellant before the astronauts board.”
Beyond the new tanks, Musk described the process of ensuring that the rocket would be safe enough to carry people as well as satellites. In the latter case, the rocket is designed to survive forces 25% larger than what engineers expect during flight. For humans, NASA insisted on a 40% margin above the worst-case force.
“Those 15 points are really difficult to do while not making the rocket really heavy,” Musk said, calling the work “hardcore stuff.” NASA worked closely with SpaceX throughout the process and indeed throughout the company’s history, with Musk complimenting the agency for its assistance, if in a backhanded way. “To be totally frank, just like a friend that really cares, [NASA] can be a pain in the ass,” he said.
To meet NASA’s standards, Falcon 9 rocket must be able to survive the loss of an engine, multiple failures in its computer systems, or the loss of any individual valve—and still reach orbit.
“We feel really confident and our most conservative customers and partners, Air Force and NASA, also feel good about the design intent of this rocket,” Musk said.