SpaceX Chief Designer Elon Musk has provided the first overview for the Starship Program since 2019, announcing a roadmap towards building a self-sustaining city on Mars.
With Starship, a rapid and completely reusable super heavy-lift launch vehicle, as the focal point, Musk hopes to achieve the goal of an orbital test launch this year, followed by a multitude of various missions from a range of launch site options, from Starbase to KSC, and even ocean launch platforms.
The Reason For Starship:
Under the gaze of the full-stack Booster 4 and Ship 20 Starship, the progress made since Musk’s previous presentation was self-evident.
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During that 2019 update, Musk had the Mk1 Starship prototype peering over his shoulder, in the middle of a small production site and just down the road from what was just the Suborbital Launch Site, occupied by Starhopper – at the time the star of the Starbase show.
“A lot has happened since then,” said Musk in his opening remarks.
The latest update came from the Orbital Launch Site, lit up for the presentation, visually adding additional contrast to the previous event.
With the successful – and speedy – stacking of Ship 20 atop Booster 4 via the Mechazilla Chopsticks, the overview was backdropped by a full-stack Starship.
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The driving force for the Starship program is fostered by Musk’s ambition to make life multi-planetary. This point was emphasized at the very opening of the presentation, with the holy grail of a rapidly and fully reusable launch vehicle.
That was proofed via the mass to orbit capability of Starship. While Elon cited the total mass launched to orbit by any nation thus far as 15,517 tons, Starship can lift 15,500t to orbit after one year of three Starship launches per week.
This rapidly increases based on launch cadence to the target of 1,000,000t that Musk believes is required to create a self-sustaining city on Mars.
SpaceX render of a city on Mars.
The goal relates to the limited opportunities for ideal Mars transit windows every two years and the amount of material needed to ensure a city on Mars is independent of Earth, should issues arise with the supply line.
For the first time in the planet’s history, such a goal is now a reality via Starship – with a payload capacity of 100-150t, dependent on the orbit, and a capacity to Mars of roughly 100t. Elon noted that this could eventually rise to 200t with orbital refilling.
Orbital Refilling with Starship – SpaceX Render
The rapid reuse of the vehicle will target reuse of the Ship every six hours, with the Booster theoretically recycled for launch every hour.
Raptor Evolution:
During the test phase, both the Booster and the Ship have continued to evolve. The Ship will move to nine engines, while the Booster will soon sport 33 engines – the maximum number of engines based on the vehicle’s diameter.
The engine itself is evolving, with Raptor 2 now deep into testing at SpaceX’s McGregor test site.
The five bays for Raptor Testing via Gary Blair for NSF L2
Raptor 1 already sported 185t of thrust. However, with Raptor 2, that increases to 230t. Raptor 2 is also “greatly simplified while increasing thrust. Half the cost at more thrust,” Musk added. The current peak thrust R2 operated at is 247 tons, so SpaceX is confident 250t will be achieved, which is “obviously essential to making SS work.”
The visual changes between Raptor v1 and v2 are apparent, with less cabling and plumbing around the engine.
Raptor 1 and 2 on show. Photo: Jack Beyer for NSF
While it’s easily visible around the entire engine, the turbopump appears to have been shrunk in size, and the plumbing has been consolidated.
Raptor 2 SN5 appears to be a Raptor Boost engine, which means it lacks the ability to gimbal or steer and cannot throttle as low as Raptor Center engines.
This engine is far more than just a step up from V1. It was a complete redesign; everything from turbomachinery to chamber nozzle to its electronics has been redesigned. This allowed items to be deleted and consolidated while the turbopumps are more robust.
Citing his dislike of flanges, many have now been converted to welds. “At high pressures and cryogenic temps flanges are a nightmare,” Musk noted. “700-800 bar in places, 11000psi, going to welded from flanges is helpful.”
Later this year, remaining fussy bits will be gone, allowing deletion of shroud
— Elon Musk (@elonmusk) February 11, 2022
Musk also noted that the preburner controllers have moved to boxes rather than being all over the engine. This allows future changes to the point where Raptor will not need a shroud – this will reduce its mass and stop being “a pain in the ass, especially for gimbaling engines,” per Musk.
“With more deletion and integration, the engine will be flameproof, and losing shrouds is a good mass saving. Probably can operate at 330 bar sustained in the main chamber without having the pre burner pressure be too high.”
This will remove choke points, resulting in less pressure loss.
Raptor testing has been proceeding well at SpaceX McGregor, including the observation of Serial Number 10, via photos from NSF’s Gary Blair (L2 McGregor). That engine was shown in action during the presentation.
Raptor 2 generates more than 230 tons of thrust at sea level, up from Raptor 1’s 185 tons pic.twitter.com/o1Rqjwx6Ql
— SpaceX (@SpaceX) February 11, 2022
The remaining challenge is mitigating against the engine chamber melting.
“The only remaining issue that we’re aware of is melting the chamber, that thing really wants to melt, it’s got like on the order of a gigawatt of heat, so it’s pretty hot, like a gigawatt is what a nuclear power plant produces, so it really desperately is trying to melt at any point in time,” Musk noted, in response to Tim Dodd, who only recently released a video on how engines avoid melting.
“So we’re flowing an immense amount of cryogenic fuels to cool the chamber and the channels, we have head-end film cooling, we’ve got throat film cooling, and we’re just trying to get the exact sort of balance between head-end film cooling and throat film cooling to not melt the chamber.”
“I think we’re pretty close, we have a couple engines in the stand that have 700 or 800 seconds of operation and several start cycles, so it’s looking positive, but that’s the remaining issue, melting the chamber.”
Addressing the production rate, Musk provided an optimistic overview. With Raptor 2s now undergoing testing at McGregor, a new production facility at the site is almost ready.
The latest view of the McGregor Raptor 2 factory, via Gary Blair for NSF/L2
“We’re scaling up production to get to one a day or better, so apart from melted chambers we’re doing well. We’ve got a lot of pumps, a lot of electronics, a lot of preburner controllers, so just not melting the chamber is very difficult and is kinda the last remaining challenge, but I think we’re very close to solving that.
“The production system has a lot of momentum like we said, next week we’ll probably make five or six Raptor 2s, and I think we’ll be at seven a week or better by next month. These are crazy numbers for rocket engines, by the way.”
McGregor will also be the focal point for testing additional limitation checks on the engines, with Musk hoping Raptor can achieve 330 bar sustained in the main chamber.
“A lot more to go on; we’re also operating a higher chamber pressure; I think over time we can operate it at 330 bar sustained in the main chamber,” he added.
Raptor 2 (#10) on the test stand at McGregor, via NSF’s Gary Blair Plane photo L2 McGregor.
“Without having the preburner pressures be too high by essentially by losing less pressure, there’s like a whole pressure ladder going from the turbopumps and preburners to the main chamber.
“By getting rid of a bunch of the choke points, we can have less pressure loss, and the pumps can effectively produce more pressure in the main chamber with less loss in the secondary systems.”
Launch Sites:
The build-up of the facilities in South Texas has been extraordinary, again evident in the changes since Musk last updated the Starship program from the facility now known as Starbase.
Full Stack at Starbase – via Mary (@bocachicagal) for NSF
It still requires a legislative process, namely an environmental assessment from the FAA, to complete before approval for launches can take place, which Musk believes may take another two months.
While the Production Site increases capacity, with a new High Bay being built alongside the existing structure, the launch site gained the primary focus for Musk’s overview.
Citing the impressive Launch Tower – with its Mechazilla system – took only 13 months from design to competition, Musk noted “Stage Zero” is as complex as the Booster or the Ship, emphasizing the successful use of the Tower with the recent stacking of Ship 20 onto Booster 4.
The forward goal is to have two towers at Starbase’s Orbital Launch Site (OLS), although such plans will likely be at the mercy of the ongoing environmental reviews.
Notably, and not just as a backup option, Musk noted that the future launch site at 39A has already passed that milestone. In addition, SpaceX and NASA recently confirmed studies are being worked on to potentially add additional launch capability at KSC’s LC-49.
Starship at 39A and LC-49, as envisioned by Jay DeShetler for NSF/L2
With South Texas and Florida’s Eastern Seaboard the two ideal launch locations, a potential scenario may see Starbase focus on the test launches, – along with operational launches with payloads such as Starlink, while KSC would become the leading launch site. This would map with KSC being the likely launch site for NASA missions such as HLS (Human Landing System).
“Starbase, I think, it’s more suited to become our advanced R&D location, so it’s where we would try out new designs and new versions of the rocket, and I think Cape Kennedy would be our main operational launch site,” Musk noted, before referring to the ocean launch platforms, two of which SpaceX has already purchased.
“Then, over time, I think we’re going to have floating spaceports like ocean spaceports, we’ve got these two converted oil rigs that are going to be turned into orbital launch sites, and they can be moved around the world.”
The two platforms currently being converted are Phobos and Deimos, although very little work has been carried out over recent months. One will gain renewed focus with the installation of its own launch tower by the end of this year.
And there she is, the other SpaceX Oil Rig, Phobos, that will be used as a floating spaceport for Starship!
The road to Mars runs through Pascagoula, Mississippi. pic.twitter.com/Jv5H8kK7kJ
— Brady Kenniston (@TheFavoritist) January 22, 2021
“Phobos and Deimos thus far have been a relatively low priority; we needed to make the launch site here work; this has been quite a difficult endeavor, so we deprioritized Phobos and Deimos.
“We’re going to take one of them and build at least a catch tower on it and ultimately we’ll, ultimately meaning I don’t know, later this year, build a full launch capability on one of the platforms.
