At the same time, NASA expressed no interest in Starship, even though if Musk's cost predictions were correct, it would cost a hundredth of SLS, the NASA flagship rocket, which has been 20 years in the making, still hasn't flown, and will cost $1.5-$2.5 billion per launch. That's partly politics—Congress has voted the money for the SLS because several states benefit from that expenditure, and it won't be voting money for Starship precisely because it will cost so much less. But it's also prudence. What if Starship doesn't work? So to keep its options open, NASA has supported several suppliers for each of its main human space flight initiatives, and has pretended not to notice Starship. Which is quite hard, really.
Now a variant of the Starship has been accepted as a candidate for ferrying astronauts from the lunar orbiter to the surface of the Moon as part of NASA's Artemis mission. Starship is way too large for this. Frankly, Starship could do the whole mission from the surface of Earth to the surface of the Moon and back, at a fraction of the cost. But this way, NASA gets a look-in at Starship's development in the hope that it can slip Starship into place as a substitute for SLS, and SpaceX gets funding for Starship's development. So we're getting a fourth variant of Starship, one that can land on the Moon, but can't land on Earth, as it will have no "fins". Hmm.
Here's Teslarati's take on this:
SpaceX’s newly-announced Moon Starship is a fairly radical departure from the Mars-focused, fully-reusable vehicle the company has been pursuing for years. Unintuitively, that may be the perfect half-step towards truly reusable Mars rockets.
With a substantial amount of money [$135 million—Musk has said that each Starship could cost as little as $5 million, excluding development costs]now on the table for SpaceX to begin initial work on its Moon Starship, it’s worth analyzing just how different it is from the Starship the company is working on today.
SpaceX appears to have returned to a fully-painted vehicle for unknown reasons. [The] white paint is likely motivated by the fact that proposed NASA Moon landers must be able to sit on the surface of the Moon after landing for at least several days, with longer stays being even better. For Starship, this means that the vehicle must likely be able to keep its cryogenic liquid methane and oxygen propellant from warming up and turning into gas, thus preventing it from igniting its main Raptor engines. White paint is at least a bit more reflective (and thus insulating) compared to Starship’s shiny steel hull but it could also hint at the use of more extensive insulation then sealed off with paint.
While visible in a render of the craft after landing on the Moon, a separate render just before touchdown fully revealed not only the addition of large vacuum-optimized retrothrusters – but a major strategic shift in how Lunar Starship will attempt to land on the Moon.
It appears that SpaceX does not plan on landing Lunar Starship on the Moon under the power of its main Raptor engines. Instead, three triple-thruster clusters – likely relying on the same methane and oxygen propellant as Raptor – will fire up shortly before touchdown to gently land Starship on the Moon. This approach has significant benefits: the Moon’s gravity is so low (~1/6th of Earth’s) that using even just one engine as powerful as Raptor to land would be incredibly difficult – a single engine could theoretically lift a fully-fueled Starship thanks to low lunar gravity.
Additionally, powerful Raptor engines – even if they could be used to land – would likely dig huge craters in the Moon’s powder-like surface during a landing burn, making it more difficult astronauts to leave the ship to explore their surroundings. However, it also means that SpaceX must design and certify an entirely new kind of vacuum-optimized rocket engine – likely using gas propellant and fed by high-pressure tanks – for an extremely critical part of operations.
Beyond new thrusters, a radically different landing strategy, and a painted (and possibly insulated) steel hull, Lunar Starship also features what looks like the tip of a Crew Dragon spacecraft in place of its nose, likely including Draco thrusters and a docking port. SpaceX has also copied the concept of Crew Dragon’s trunk section, installing a curved solar array that wraps around a large portion of Starship’s conical nose. Lunar Starship also offers what looks like the first official glimpse into a new style of Starship landing legs, prototypes of which are already installed on Starship SN4.
Additionally, SpaceX has chosen to entirely exclude a windward heat shield from Lunar Starship, as NASA’s plan is (rather painfully) to launch astronauts to the Moon with SLS and carry them to lunar orbit and back to Earth on Orion. Starship also appears to be missing its complex and extensive habitation module and massive gallery window. All that absent hardware is almost certainly meant to dramatically simplify Starship to the point that even NASA would consider funding its development. Incredibly, that strategy appears to have worked and it’s possible that we could see Lunar Starships flying to the Moon as early as 2022.
While a stop at the Moon is decidedly one-way and requires a bit of a one-off Starship variant, what SpaceX has really done is found a way to get NASA to help fund the development of its fully-reusable next-generation launch system. Even if NASA’s Artemis program dies, flounders, or goes nowhere, SpaceX will likely still benefit significantly, much in the same way that NASA’s assistance developing Cargo Dragon and Falcon 9 was a huge boon for the company.
[Read more here. Lightly edited for clarity]
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| New vs old Starship concepts Note three oval openings of the triple thrusters half way up the body, as well as the cargo bay and the lift. |
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| Starship landing on the Moon using three sets of triple thrusters, high up on the body. |
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