sevenperforce

Elon confirms six legs: two leeward, two windward, one under each fin. No word on shape.

Something that couples baryonic matter to gravitational field lines.

Alternately, what if it looks like this?

It could be a forward strake for transition between the tops of the Plasma Deflector Shields and the raceway chines, or they could be the blisters for landing leg deployment. What if the landing legs deploy from inside the skirt, through a hole cut in the stainless steel? This couples the legs directly to the thrust assembly while still giving a wider stance.

Nose cone is coming off the fairing. I wonder if that was a preliminary check to make sure it fits, and then they are going to assemble lego-style. Makes sense. They wouldn't want to suspend the fairing by the bottom of the cone.

That was in reference to SuperHeavy, the lower booster. WAY faster. I was expecting the crawler to, well, crawl.

Correct, you use your propellant as your coolant. Pump it through the nozzle and throat walls to cool them, tap off what you need for autogenous pressurization, and then pump the rest into the thrust chamber. You lose nothing at all by preheating your propellant. Trying to orbit anything without staging will require that most of your mass is propellant. Though the percentages get better as you get bigger. If a stretched Falcon 1 first stage was launched with a single Block 5 Merlin 1D, it could just barely make orbit without payload. A Falcon 9 Block 5 first stage could make orbit readily with about 1-2% payload fraction. SuperHeavy could make orbit with 3-5% payload fraction. For any given engine type, the square-cube law means that bigger is always more efficient. If it is using staging, it is not an SSTO. The great SSTO paradox is that any engine good enough to use on an SSTO is even better to use on the first stage of a TSTO.

They look like they are far more triangular in cross-section than the lower flaps: What if the forward fins are fixed rather than moveable??

Won't react with uranium, doesn't have significant thermal expansion. There's a little neutron activation and some neutron embrittlement but it's not significant; you'll need to reprocess your uranium before the TaHfC starts to cause problems.

Nope, doesn't make a difference. For an airbreathing or air-augmented engine, you want the maximum mass flow regardless of how large or small your vehicle is, because high mass flow will decrease thrust-specific fuel consumption, meaning you use less propellant. If you want a bigger SSTO, you simply need more engines.

You don't need more heat-resistant materials; you can just use active cooling. There is no relationship between gross vehicle weight and "thermal energy".

Fantastic idea. As usual, great minds think alike. We discussed this very idea at length about two and a half years ago, both in this thread and on the CDE forums. Can't find the CDE forum thread, but we found that for SSTO applications, using a pebble-bed reactor with molten uranium inside of a tantalum halfnium carbide shell would be the ideal near-term design, most likely running on simple water for impulse density and ease of refueling. The only thing with higher performance that we could actually build without irradiating the world would be a nuclear lightbulb. NERVA is absolutely performance-limited by reactor temperature. Get it too hot, and it melts. The nozzle and throat are actively cooled, just as in the SSME or F-1 or Raptor or Merlin, so they can handle any operating temperature. You can't actively-cool the reactor core because that's the thing that needs to be as hot as possible. It's a common misconception that nuclear-thermal rocket engines are somehow unbelievably hotter than regular engines. They aren't. NERVA reached temperatures of around 3000K, while the SSME reached nearly 3600K. NERVA was more efficient not because it was hotter, but because the SSME required you to stuff a bunch of heavy oxygen atoms into the mix, while NERVA runs on pure hydrogen which is lightweight and thus achieves a higher specific impulse. This is also the reason that nuclear engines have shoddy T/W compared to any bipropellant chemical engine.

I wonder if they have already fit the legs under the skirt along with the engines. DC-X certainly had a footprint smaller than its diameter, after all.

I am so missing the like button. The critical limiting factor for aerocapture is capture into the SOI during the first aerobraking pass. After that, you can take as many aerobraking passes as gently as you like to bring the apogee down further and further, and then finally make your entry, "riding T4 all the way down" as Elon puts it.

We will see aerocapture maneuvers between Earth and Mars.

The airbreather part just bumps the effective Isp for the launch. The one I'm interested in is the staged-combustion version. A regular FRSC hydrolox engine is in the center, an air-augmentation (GNOM-style) duct around the engine, and the turbocharger blades spun by turbopump combustion tapoff that bleed fuel for downstream combustion. My remarks on the necessity of the turbocharger blades: A deeper review of the whitepaper leads me down some interesting paths. The fan blades themselves are of course critical to vertical takeoff, providing augmentation of ~320% at liftoff. Without them, static thrust would presumably be only a fraction (~26%) of GLOW, making liftoff impossible. However, they provide rapidly-dropping augmentation as increased airspeed makes their compression cycle less efficient and ram compression begins to provide more assistance. By Mach 1, augmentation drops to 220% and thrust has decreased to 76% of liftoff thrust while the vehicle's gross mass has only dropped by 2%, thus lowering T/W by 22%. By Mach 1.4, augmentation is only 180% and T/W is 32% less than at liftoff. According to the whitepaper, fan compression continues to contribute up to Mach 8 (a bold claim), but it would necessarily be only a tiny contribution. For as much trouble as these fan blades promise to be, I'm not certain there isn't a better alternative. Certain fanless ducted rocket designs can boost specific impulse by up to 80% with no forward airspeed. An ideal design would have an immediate increase in T/W rather than a decrease, which is critical given the gravity drag on the early stages of flight with something like Prometheus.

Seeing a second raceway on the leeward side of Starship: It also appears they are prepping for another nosecap lift.

It is a big shiny toy rocket. It is also quite serious.

No, the vertical lines are weld points. Also, it is windward side so I don't see anything actuated going there. Maybe they are going to mount experimental TPS there?

Presently three areas of work: In red we have a team on a crane prepping the top of the fairing for nosecone attachment; in blue we have a team working on the external face of the nose cone immediately after an additional header tank was inserted; in green we have a team doing something to the odd stiffener band on the windward side of Starship.

I have connected with Bucknell on LinkedIn and necro'd an active NSF thread where he is answering some questions: https://forum.nasaspaceflight.com/index.php?topic=43344.msg1995132#msg1995132

The forum merged two posts. The first one, about the windward side, was independent of that photo. It's clear that we are looking at the windward side of the main body based on this image: This is just the raceway cover forward of the aft fins (or, as I am now calling them, Plasma Deflector Shields), but you can see from the asymmetry that the left side of the image represents the windward surface and the right side of the image represents the leeward surface. As for knowing that the fillets on the fairing section represent the location of the canards -- I don't know for sure, but it does look like they protrude too far to be simple raceway covers, as above. Though I could be wrong. Also, I would be disinclined to expect any external raceways on the fairing section because they have internal space for piping.

Higher-res pictures have made it clear that we are looking at the windward side of Starship Mk1. Also, we now have a very good indication of where the forward flaps will be located:

I'd wager that if something is moving then it is intended to be moving but I could be wrong.

They are currently doing actuation tests on one of the fins.