Closing the case for reusable launchers
by Jeff Foust
|“In order to achieve effective reusability, if you want missions to go to high orbit or to escape velocity, you really need the ocean landing,” said Musk.|
Everyone else, though, seemed to be focused on what would happen with the rocket’s first stage. Four previous times, dating back to January of last year, SpaceX had tried to land the stage on a ship in the ocean. All four of those times failed, even while coming tantalizingly close at times: a January landing attempt failed when the stage landed on the ship, but toppled over when one of the landing legs failed to lock in place. By contrast, the first attempt to land a stage back on land, last December, succeeded spectacularly (see “A step towards reusability”, The Space Review, January 4, 2016).
So as NASA continued to follow Dragon into orbit, SpaceX’s own webcast cut away during ascent to the first stage’s approach to “drone ship” landing platform known as Of Course I Still Love You. An aerial view showed the first stage descending towards the ship—too fast? off course? some wondered—then slowing and straightening above the deck. The stage touched down on the deck and bounced slightly as the engine shut down. And it didn’t topple.
The cheers from the hundreds of employees at SpaceX headquarters in Hawthorne, California, when the stage safely landed were as loud as they were in December when SpaceX landed a stage on land. After four previous failures, SpaceX had finally demonstrated that it could land a stage at sea.
That landing demonstration is important, since SpaceX’s plans for reusability will require ocean landings on many of its launches, despite demonstrating the ability to return to near the launch site. While the stage on this mission had enough performance to be able to return to land, upcoming missions, such as launch of communications satellites to geostationary orbit, will require additional performance that prevents a return to land.
“On this particular flight we decided we wanted to go to the drone ship and see if we can get a successful landing on the drone ship done, partially also because the next two or three flights are going to be drone ship landings; there’s no choice there,” said Hans Koenigsmann, vice president of flight reliability at SpaceX, during a news conference the day before the launch.
At a post-launch press conference, SpaceX CEO Elon Musk took time to provide a primer on orbital mechanics to explain why it will continue to require drone ship landings. “About half of our missions will need to land out to sea: any missions that are going to geostationary orbit, or to escape velocity—anything beyond Earth—is likely to need to land on the ship,” he said. “In order to achieve effective reusability, if you want missions to go to high orbit or to escape velocity, you really need the ocean landing.”
|“I think this was a really good milestone,” Musk said of the landing.|
The stage, whose landing legs were welded to the ship’s deck to secure it in place shortly after the landing, is now being shipped back to Florida. (Musk said at the press conference is was due to arrive Sunday, but the drone ship didn’t make it Port Canaveral until Monday night.) “Our plan is to basically fire it ten times in a row on the ground,” most likely on the pad at Cape Canaveral, Musk said. “If things look good, at that point, we feel it’s sort of qualified for reuse and launch.”
That relaunch could take place as soon as June, he said. “We think it will be a paying customer,” he said, “but we have to have some discussions.”
“I think this was a really good milestone,” Musk said later of the landing. “In order for us to open up access to space, we’ve got to achieve full and rapid reusability. And being able to do that for the primary rocket booster is going to have a huge impact on cost.”
Among those watching the launch—and landing—webcast were attendees of Space Access ’16, the annual conference about space transportation held in Phoenix. The 4:43 pm Eastern time launch fell during the lunch break three hours behind in Arizona, but most attendees returned to the conference room to watch the launch, cheering when the first stage landed successfully.
Ironically, the first speaker after lunch, not long after the landing, was someone from United Launch Alliance. “It's going to be a bit of a challenge to follow that,” acknowledged ULA’s Eric Monda at the beginning of his presentation.
What made the landing more remarkable, in the minds of some attendees, was that it was the second vertical landing of a reusable vehicle—or at least potentially reusable vehicle—that had flown to space in less than a week. On April 2, Blue Origin made another test flight of its New Shepard suborbital vehicle, flying to an altitude of a little more than 100 kilometers. Its propulsion module, which made the powered vertical landing, was the same one that flew on two earlier test flights last November and in January.
Those achievements have helped reduce the doubt that at least partially reusable launch vehicles, where just the first stage is recovered and reused, are technically viable today. (New Shepard is, of course, only suborbital, but Blue Origin has made clear it’s developing that reusability technology with an eye towards an orbital launch vehicle with a reusable stage.)
However, technical feasibility is only one issue with reusable vehicles. Another is economic: can the vehicles be refurbished and reflown enough to make the reusability worth the cost of development? And if reusables can offer lower launch costs, by how much can they expand the market?
The audience at Space Access, which includes many long-time advocates of reusability as well as people who have tried to develop such systems in the past, suggested that doubts remain about those issues.
“I have a contrarian view to ‘SpaceX solves all our problems’ or ‘Blue Origin solves all our problems,’” said Gary Hudson, a veteran of several RLV efforts, during a conference panel April 8. “I think that existing firms can’t and won’t solve the access-to-space issue.”
Hudson illustrated the “real problem” with reducing space access costs with a photo of a large crowd of SpaceX employees celebrating the December first stage landing. “There are 4,500 people on SpaceX,” he said. “Why so many bodies?”
That size, he said, he due to the “fetish and fashion” of vertical integration that other companies have also adopted. “Vertical integration, in my mind, is exactly the wrong thing that this industry should be doing,” he said. Companies should, instead, do a better job of managing their supply chains and automate processes wherever possible to reduce the number of employees, and thus their cost to the company. “You shouldn’t add an employee until you absolutely, positively need that person.”
|“Vertical integration, in my mind, is exactly the wrong thing that this industry should be doing,” Hudson said.|
Another issue that Hudson raised is the elasticity, or lack thereof, in the launch market. It’s long been understood that dropping prices will initially stimulate only limited initial demand, causing overall revenue to drop. Past studies have suggested that, once prices fall to a certain point, demand does become more elastic, increasing more rapidly as prices continue to fall.
To get back to the same level of revenue as an expendable rocket that, at current prices, launches ten times a year, a low-cost reusable vehicle might have to fly hundreds of times a year. “This is what I call the valley of death for cash flow,” Hudson said.
So what are the markets that will demand hundreds of launches a year? Another conference panel examined potential markets for low-cost, frequent launch, although there’s no consensus yet about what markets, if any, can provide that.
“As far as one great killer app, so to speak, I don’t think we see that yet,” said Clark Lindsey of NewSpace Global. “But there are a lot of things happening, a lot of new kinds of businesses popping up.”
Many on the panel, and elsewhere at the conference, argued that the biggest demand for low-cost launch won’t easily be foreseen. “There’s going to be enough people out there with enough totally off-the-wall business plans that close, once you have launch costs down enough,” said Doug Jones of XCOR Aerospace. “We don’t know what they are, but somebody will come up with it.”
That uncertainty is understandable—many other technologies have created demand not foreseen when they were developed—but also is unsatisfying, particularly to those who might want to invest in the development of reusable vehicles, or pin their business plan to their existence in some way or another. It’s tough to make investment decisions, or even vehicle decision decisions, if you’re not sure exactly who will use the vehicle, and how frequently.
Thus, the technology for reusable launch vehicles, once obsessed over by governments, companies, and individuals as the major challenge to low-cost space access, may no longer be that. You can soon build them, but who—in the form of customers—will come?