Will Musk's starship reach orbit this year?

The VAB’s quite a bit taller. 525 feet overall, with a 456 foot door. The Saturn V itself was “just” 363 feet.

The gantry and everything went inside the VAB:

Explain this? Fully liquid vehicles are lighter because…? Cryotanks, even empty, are just flipping heavy? Or were you referring to solid boosters being heavy?

Liquid-fueled vehicles are moved while the fuel and oxidizer tanks are empty, therefore (relatively) light; being entirely full of inerting gasses or air.

Solid-fueled vehicles are moved while fully fueled. The fuel is cast inside the engine casings back at the engine factory.

If you have to haul a rocket from here to there on the launch grounds it’s a lot easier if you can add the heavy fuel (and oxidizer) later after the vehicle is fully situated on the launchpad.

Got it, thanks.

The air alone in the Super Heavy booster weighs about 5.5 tons. But it’s buoyant by the same amount, so it’s ok.

Somehow your comment about equal buoyancy in a stainless steel vehicle reminded me of the Battle Royale we had for maybe 500 posts a few years ago with some person who Would. Not. Understand. that a balloon (or airship) filled with vacuum was all kinds of Treknobabble-level impossible while hydrogen or helium does 90+ percent as well as magick vacuum and is actually real easy workaday tech.

Which recall got me to free associating, which is always dangerous.

Now if SpaceX warmed the air to make it lighter than ambient I wonder if they could scale that up a bit and MacGyver up a rocket-dirigible? Now there’s a hermaphrodite for the ages. Make it all steampunky too. :grin:

The tanks are lightweight but I don’t think they’re that lightweight. And of course the engines weigh a lot.

There are some proposals for balloon-based rocket launch. One of them called Zero 2 Infinity. Their rocket has the unfortunate name of Bloostar:

Calling their business sketchy is a disservice to sketchy businesses everywhere. I think they spent their entire budget on the website.

Balloons are cool and all but they need to be enormous for the amount of lift they provide, and they really just don’t get you much in rocket terms. A few tens of kilometers in height and atmospheric conditions more favorable for a high expansion-ratio engine. But rockets are about speed more than anything and a balloon doesn’t help.

Another proposal I saw was a hybrid balloon and lifting body. It was covered with solar panels and could allegedly get to orbit via electric thrust. Somehow the aerodynamic lift eventually took over the buoyancy and it just kept going faster and faster. Also quite skeptical about that one.

The tyranny of the rocket equation is such that the first stage which gets you that first few kilometers up is more massive than the rest of the stages. To the point that there have been serious proposals to use rocket sleds going up the face of mountains to get that first 5,000-10,000 feet altitude and Mach 1-2 for rockets. The balloon idea goes back to 1950’s sounding rockets; the catch is that it only works for pretty small rockets and payloads.

A rockoon. They were planning to send idiot SovCit steam rocket guy up into one until he augered into the desert hardpan.

A rockoon could, in principle, work. The equations are there for smoothly transitioning from buoyancy to aerodynamic lift to orbit, as altitude and speed both increase. And it’s probably the only viable way to travel to and from Venus (whose upper atmosphere isn’t actually all that inhospitable, as space goes).

But like most “cheap” access to space plans, it would require a tremendous up-front investment. You’d have to do a lot more engineering to even figure out which of the many plans is best, before doing even more lot of engineering and a lot of spending to make whatever you chose a reality.

Slightly off topic, but does anyone know of any proposals to assist a rocket launch with a giant push from the ground-support equipment? Like a giant sling-shot or spring that can be energized over time, released at t = 0 to supplement the lit rocket to say, the momentum it would traditionally have after clearing the launch tower? Meaning, store the energy required to clear the launch tower in the tower itself rather than the rocket? It seems like with modern batteries this would be feasible.

Thinking about this a little more, it would be like a stage 0.5 that could use rockets to supplement the liftoff for a few seconds… the difference is the mass of the engines and fuel would not penalize the rocket.

Newer ICBMs use a pop-up system that clears the silo before the main engines are ignited. But I don’t think it’s cost-effective for satellite launchers.

I’m always thinking we could do something with magnets, energize an electromagnet below the rocket, repulsing an electromagnet of opposite polarity in the rocket, ride the impulse and let go of the electromagnet in the rocket… and you have a good bit of impulse.
The problem would be the sudden acceleration probably, not useful for live cargo…

Yeah, we’ve known since the 1960s that space is the ultimate giant economy-size package. The marginal cost can be dropped ridiculously low if one presumes an enormous economy of scale.

For details of maglev launching to lunar orbit (and the reverse), refer to the classic paper on the subject.

Pic of the new flaps:

Compared to the old ones:

Looks like they’re thinner and that the hinge is more flush with the surface. Also smaller overall and moved closer to the nose. Hopefully that does the trick.

And now that I’m thinking about it, these nose cones look a lot like fat penguins…

I think the limiting factor in launches is acceleration, anyway, and 4ish gees for a hundred meters doesn’t really amount to much, on the scale of rockets. A launcher might make a difference if it goes all the way up the side of a mountain, but not just for something the size of a normal launch gantry.

Launching from the Moon to the Earth, using any sort of launch technology, is much, much easier than Earth to Moon (as Heinlein acknowledged). Luna is a much shallower gravity well, and the lack of an atmosphere is also a huge advantage. Consider that the Apollo astronauts were able to get off of the Moon in a rocket the size of a small car, and compare that to the Saturn V.