sevenperforce

Looks like my guess about the tile patterning was pretty close to correct. Moving from top to bottom, the rows of tile studs are as follows: Down Up x2 Down Up x2 Down Up x4 Down Up x3 Down Up x4 Down Up x5 Down Up x11 There is an alignment discontinuity between each downward-pointing tile stud row and the upward-pointing tile stud row directly above it. It feels like the most straightforward approach will be to simply use pentagons with a flat side for each of those misaligned rows, but we will see. Assuming that this is the nosecone for SN20, I wonder if we will see glue-on tiles for the very tip or if we will see a thicker single-piece nosecone.

The header tank is only the diameter of the spherical cap at the tip of the ogive.

Friction has nothing to do with it. The moon is responsible for the intensity of the tides. No one is claiming that the moon is causing tsunamis. It is like slowly filling up a swimming pool while people are already constantly climbing in or out of it. If you are constantly adding water to a pool while a bunch of people are climbing out, the water level won’t rise very quickly, or maybe even at all. But if all those people then climb back in at once, the water level will rise very very quickly.

That’s really huge. Obviously it is a shame that the mission will take a little bit longer due to gravity assists, but it’s not like SLS was going to be ready anytime soon, so it will probably get to Jupiter even sooner. All reusable rockets tend toward the Shuttle, apparently. What about a door opening in the opposite direction? At least that would make loading payload easy. Unfortunately, nothing about the Starship outer mold line makes for particularly good payload deployment. Either you need a payload adapter that can tilt itself forward in order to point stuff out the door before release, or you have to have a payload adapter that handles transverse loads. How was Hubble deployed? Yes, it would make sense to have a single rail traveling from the base of the LOX header tank to the top of the methane tank with the ability to rotate, and then your payload dispensers would crawl up and down it. Not too dissimilar from the configuration of the last rideshare Transporter 2 mission.

Oooooh, nice catch!! And here we have it in all its glory... Just as I suspected, a bunch of stiffeners. Interesting shape overall, though.

There's just no way the booster can handle the landing with the capsule. It's not aerodynamically stable in the engine-first orientation. The capsule has to separate in order for the ring fin to open up and provide sufficient drag.

Oooooh, nice catch!!

Agreed. I would say that if you are conducting experiments during spaceflight — payload specialists, for example — then you should still qualify as an astronaut, even though that doesn’t fit the FAA’s “public safety contribution” standard. The Shuttle flew plenty of payload specialists and they should all be considered astronauts. What about someone like Tom Cruise? He’s going to space for his job, but his job has nothing to do with science or spaceflight.

Yep, that was my thought as well. Once everyone was out of their seats, it looked very crowded. Hard to do a backflip if you’re gonna kick someone in the face.

No tiles yet on the curved regions. I wonder how they will do the lifts when they have the tiles affixed.

One of the challenges with allllll of these threads is that it’s really unclear what you are looking for. Are you creating a fictional universe where you want a reusable rocket that can land on a planet, refuel itself, and take off to orbit again? Or are you talking about a real world solution? If the former, then seriously: just write it however you want. It is your fictional world. Bend the technology to fit your plot, not the other way around. If the latter...well, that’s where things break down, because what you’re describing/suggesting/hypothesizing simply doesn’t reflect reality. If you want a rocket to have increased thrust via “increas[ing] propellant flow or mass”, you need bigger turbopumps, full stop. The bigger the turbopump, the more propellant you can push through your engine. Don’t think in terms of total thrust. Think in terms of thrust-to-weight ratio. The goal is to have an engine which can lift 70X or more its own weight on Earth. Adding “more thrust” doesn’t do any good if your engine weight grows just as fast. As for increasing exhaust velocity: increasing exhaust velocity does not necessarily increase thrust. For example, SpaceX could raise the specific impulse of the existing Raptor Vac just by narrowing the throat, which increases the expansion ratio but decreases thrust. And an “engine’s tolerance” for heat is really not a big deal. You can run an engine as hot as you want as long as you use film cooling or regenerative cooling. The only time you run into problems with heat tolerance is certain solid-core nuclear thermal rocket designs, where the temperature is limited by the melting point of the nuclear fissile material. You can avoid that fairly easily (if anything in nuclear rocketry is easy) by enclosing the fissile material in tungsten or tantalum halfnium carbide and allowing the fissile material to melt inside it. Don’t focus on thrust; focus on thrust-to-weight ratio. It doesn’t do you any good to build a nuclear engine with as much thrust as a Raptor if the darn thing weighs fifty tonnes. Playing KSP can really help give you a better intuitive sense of all this. I strongly recommend it. You can build a nuclear engine with as much thrust as you want; there’s not really any meaningful upper limit. But the more thrust you want, the heavier your engine will become. Nuclear reactors are heavy; nuclear thermal rockets cannot achieve anywhere near the thrust-to-weight levels of a conventional chemical engine. It’s wildly, wildly disproportionate. For reference, NERVA produced four times its own weight in total thrust. The Space Shuttle Main Engines produced 78 times their own weight in total thrust. The Merlin 1D produces 200 times its own weight in total thrust. DUMBO might have gotten up to 8-10 times its own weight in thrust, which is still just wildly too low to be used for liftoff. LANTR (the LOX-Afterburning Nuclear Thermal Rocket) injects liquid oxygen into the nozzle of an ordinary nuclear thermal rocket, which burns with the hot hydrogen and multiplies thrust briefly at the expense of efficiency. Even so, it only produces about three times as much thrust, which still pales in comparison to even the least powerful chemical rockets. Again, here’s where it’s unclear what you’re going for. Are you proposing a real-world rocket or a fictional one?

ERMAGERD FLAPS Whoaaaaa, seeing the outline where the aft flap is going to be really puts it in perspective. The flaps have less extension away from the centerline of the booster. The new aft flaps have less lateral extension. Evidently the flight test data was really really good.

Have you ever seen a tide?

I believe they did a maximum altitude abort test, let me look. Yep, July 18, 2018. They fired the abort motor shortly after MECO and separation. It reached 120 km, about 14 km higher than on a nominal flight.

If nominal stage separation failed, I would be rather concerned about whether firing the LES would make things better or worse. If you have some bolt that didn’t release when it was supposed to and you fire the LES, it could get very...toasty. Although I suppose you’d have to have a go-no-go at some point.

Intuitively, yes. But from an engineering perspective, it is EXACTLY the same problem as landing Falcon 9 at zero meters, zero velocity on deployable legs. You have a load-bearing mechanical system that has to reach its full deployment at the exact same time as your rocket reaches a predetermined point. You have to have a way to damp contact. The only difference is that putting the “legs” on the tower is that you have more mass budget for the mechanical system. I believe there was an Elon tweet saying they would try to go without it.

I don’t think New Shepard has that capability. The rocket is not stable in the tail-first configuration with the capsule still attached; it needs a successful separation in order for the airflow through the ring fin to provide the necessary drag during descent. Also, there’s no way New Shepard has enough prop margin to land with the capsule still attached. Well @tater was talking about egress from SpaceShipTwo, not from the New Shepard capsule. There is no egress from the New Shepard capsule and I don’t think they are wearing parachutes either.

I would certainly hope so. But even in an abort, capsule separation is still a LOCV-sensitive event. If you fire the abort system and the capsule still doesn’t separate, you are not going to space today, or ever.

I will say, very humbly, that there are people who do not know much about science and discuss it to learn more... ...and there are people who refuse to learn.

I didn’t think I would say this until I saw the video, but I’m not so sure I would prefer New Shepard to SpaceShipTwo. New Shepard has an escape system, which of course is nice. But New Shepard also has a capsule separation event as a LOCV point, which SpaceShipTwo doesn’t have (if SS2 fails to separate, the carrier aircraft can still land in one piece). And it looks like there is way, way more room in SpaceShipTwo’s cabin than in the New Shepard capsule. New Shepard may have bigger windows and technically go higher, but what of it?

Well clearly I misread. Whoops.

Neptune rotates prograde relative to its orbit, like all planets other than Venus. Triton orbits Neptune retrograde relative to Neptune’s rotation and is the only large moon in the solar system to do so. This mission would enter a prograde Neptunian orbit in order to use Triton to adjust its orbit repeatedly. Gravity assists are most efficient when your path is opposite the body you’re getting the assist from.

I didn’t think I would say this, but it looks crowded in there.

Also because part of the whole mission profile is to orbit Neptune prograde, opposite (but coplanar with) Triton, and thus use Triton for gravity assists to alter trajectory for free. But still, I want a lander.

They should include a Triton lander.