The above rendering of the Big Falcon Rocket, or BFR, as the launch system is called, shows it punching through the cloud tops of Earth and flying toward space. Musk shared the image to Twitter on Monday morning.
Musk also tweeted a side view of the vehicle (right) that more clearly shows its two stages: a booster, or lower stage, and an upper-stage spaceship.
Last week, SpaceX shared an illustration of the ship in space, flying around the moon while firing seven rocket engines.
That picture, below, shows the Big Falcon Spaceship — as it’s sometimes called by Musk and his company — without the booster.
All three images were released just before a major announcement from SpaceX on who the first person will be to ride a BFR spaceship around the moon.
"SpaceX has signed the world's first private passenger to fly around the Moon aboard our BFR launch vehicle — an important step toward enabling access for everyday people who dream of travelling to space," SpaceX said on its website.
But these new images may be more important than the revelation of the passenger’s identity. That's because they show off subtle but important differences in a vehicle that is ultimately supposed to ferry up to 100 people and 150 tons of supplies to Mars — and, of course, a person around the moon.
Musk, who is SpaceX’s chief designer, publicly described the BFR and showed renderings of the system at the 2017 International Aeronautical Congress (IAC).
According to those plans, the BFR would be 105 metres tall and 10 metres wide. It would be capable of carrying 100 people and 150 tons of supplies.
The newly released renderings show each stage of the system having roughly the same proportions. However, the spaceship’s body appears to have got a significant design revision.
The 2017 version of the ship had one delta wing, as Musk called it, near its heat shield. The wing is designed to help the ship plough through planetary atmospheres like those of Earth and Mars.
“Depending on whether you're landing on a planet or a moon that has no atmosphere, a thin atmosphere, or a dense atmosphere, and depending on whether you're re-entering with no payload in the front, a small payload, or a heavy payload, you have to balance the rocket out as it's coming in,” Musk said during his 2017 IAC presentation.
He added that his engineers originally tried to avoid having even one delta wing, but said “it was necessary in order to generalise the capability of the spaceship such that it could land anywhere in the solar system.”
It appears one wing wasn’t enough, though: There are now three wing-like structures on the spaceship.
SpaceX may have decided that these wings are necessary for the system to safely return to Earth. Or perhaps they're for slowing the ship down as it enters Mars' atmosphere, which has air about 1% as dense as our planet’s.
The renderings also show another wing on top of the ship, which resembles a tail fin like those on NASA’s space shuttle orbiters. Musk called it “forward moving wing” on Twitter; presumably it's there to help further stabilise the ship as it moves through air.
We contacted several aerospace experts to get their takes on these design changes.
Greg Autry, the director of the Southern California Spaceflight Initiative, told Business Insider in an email, “I think it is really healthy to see this iterative change happening, because I believe we can assume it is based on actual development and simulation going on.”
“Elon is an incrementalist and to a great extent he is always thinking aloud. I admire this, but people who do this openly get criticized when their ideas evolve,” Autry said.
SpaceX's approach to designing rockets and spaceships is notably different from the way NASA and others do it, he added.
“NASA would design something like the Space Shuttle on paper and then build that damn thing come hell or high-water. Insights developed during the early production were usually ignored,’” Autry said. “Elon is from the software world, where rapid prototyping and iterative development are the norm ... Expect a different model from him, with some visible hiccups and in the end a safer and more efficient design.”
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