by Jeff Foust — September 29, 2017
BFR lunar base
An illustration of a SpaceX "BFR" spaceship at a notional future lunar base. SpaceX CEO Elon Musk emphasized the versatility of the updated BFR system in a Sept. 29 speech. Credit: SpaceX
ADELAIDE, Australia — SpaceX Chief Executive Elon Musk announced plans to develop a revised version of a reusable interplanetary transport system that he said would be more affordable and versatile.
Musk, speaking before a packed auditorium at the conclusion of the 68th International Astronautical Congress here Sept. 29, unveiled an updated version of the Interplanetary Transport System he announced at last year’s conference in Mexico.
The new version of the reusable booster and spaceship, known collectively only by the codename “BFR,” are scaled down somewhat from that original design, making it feasible for them to serve other markets, like satellite launch, while maintaining the ability to support human missions to Mars as soon as the mid-2020s.
“Probably the most important thing that I want to convey in this presentation as that I think we’ve figured out how to pay for it,” he said early in his 45-minute address, which lacked a question-and-answer session afterwards.
Musk said SpaceX will pay for the new vehicle by replacing the company’s existing Falcon 9 rocket and Dragon spacecraft, and upcoming Falcon Heavy rocket and Crew Dragon spacecraft, with the BFR system. That, he said, will free up resources that can be devoted to production of the boosters and spaceships.
“This is really quite a profound — I won’t call it a breakthrough, but a realization — that if we can build a system that cannibalizes our own products, makes our own products redundant,” he said, the company’s resources can then “be applied to one system.”
Musk didn’t give a timeframe for phasing out the company’s existing vehicles, although he said SpaceX could stockpile some older vehicles for “conservative” customers who would prefer to use them. “But all of our resources will then turn towards building the BFR,” he said. “We believe we can do this with the revenue that we receive launching satellites and for servicing the space station.”
Musk
SpaceX CEO Elon Musk speaking at the 68th International Astronautical Congress Sept. 29. Credit: SpaceNews/Jeff Foust
The revised version of the BFR features a booster stage with a diameter of 9 meters, down from 12 in the original design. It uses 31 Raptor methane-oxygen engines in its first stage, versus 42 engines in the original version. The spaceship, a combination of upper stage and spacecraft, would have six Raptor engines, four outfitted with nozzles for operating in vacuum and two for sea-level conditions.
The combined stack will be able to place 150 metric tons into low Earth orbit, and be able to return 50 metric tons. The spaceship can also be refueled in orbit for missions beyond Earth orbit, particularly Mars.
Musk argued that BFR could enable new applications for satellites, such as telescopes with large apertures or the deployment of massive constellations of spacecraft. He also claimed that the spaceship was not oversized for servicing the International Space Station. “I know it looks a little big,” he said as he showed an illustration of the spaceship looming over the station. “But the shuttle also looked big, so it’ll work.”
Musk, in his talk, showed that the BFR spaceship could land on the moon, adding that it could return directly to Earth without the need for refueling on the moon. The system could also be potentially used for point-to-point suborbital travel on Earth, saying that results of an internal analysis of that application was “quite interesting.”
Musk’s emphasis, though, remains on Mars, as he showed a video of how a base, and later a city, could be built up there through flights of the BFR. Musk said SpaceX’s goal was to launch at least two cargo spacecraft to land on Mars in 2022, followed by four spacecraft, two carrying crews, landing in 2024.
“That’s not a typo, although it is aspirational,” he said when he showed a chart with the 2022 date. “But if not this timeframe, I think pretty soon thereafter.”
Work on the first ship will begin by the second quarter of 2018. “It will be ready for launch in about five years,” he said. “Five years seems like a long time to me.”
Earlier in the talk, though, he acknowledged the challenges developing the far smaller Falcon Heavy, which will make its first launch “hopefully” by the end of the year, several years behind its original schedule.
Musk spent much of the talk going into technical details about the BFR’s design, including the use of lightweight carbon composite tanks, efficient engines and autonomous rendezvous and docking technology. However, he said little on other aspects of the system, in particular its price, other than to say it would have a far low cost per kilogram than other launch vehicles.
Musk later posted to Instagram an animation of the point-to-point application of the BFR. “Cost per seat should be about the same as full fare economy in an aircraft,” he wrote. “Forgot to mention that.”
source: http://spacenews.com/musk-unveils-revised-version-of-giant-interplanetary-launch-system/