wumpus

How could they possibly be on schedule for 2024? They would need at least one test flight for SLS, one complete and tested lander, all the gear that needs to go on multiple flights. Seems like NASA has gone beyond accepting re-use and retropropulsive landings and taken up "Elon time". According to the infallible wiki all the lander contracts are listed as "study". Don't expect "old space" to make a single drawing ready without a contract to design. I can understand that no NASA employee would ever suggest that such a monumental program would happen in some other administration's tenure (it is entirely possible that NASA only made it to the Moon because they were given the full 8 years [into the Nixon administration] to get to the Moon, not before 1969 when Kennedy could no longer remain in office (assuming he was still alive and won in 1964)).

It costs $25k just for the permit to climb Everest. Don't forget the cost to travel to one of the most remote parts of the world, and stay until you at least acclimate to base camp. It looks like only 700 to 1,000 cough up the money (and take the risk) to climb (although 35,000 visit base camp) each year. About half make it to the top. And about four are left dead on the mountain each year. I doubt they will have much trouble selling tickets. Of course, a lot depends on how impressive it is on the cocktail party circuit.

Pretty sure they sold Yusaku Maezawa a ticket on the Falcon Heavy before dropping the crew paperwork. So presumably it is possible, although it would probably put a dent in the schedule (unless you still need SLS. Starship should be ready before SLS). Apollo LEM was ~18tons, meaning that it probably can't be fitted with something to circularize once it makes it to LTI (assuming fired from FH). Also I doubt anyone is going to achieve modern safety levels in 18 tons or less, every gram was sweated there.

Pretty sure Falcon Heavy + Dragon 2 can make it around the Moon (not stopping to orbit) and back. Dragon has ~400 m/s delta-v and the minimum for a lunar lander is >3000m/s (I'm pretty sure Dragon 2 doesn't have that). I don't think there's much a service module can provide, except perhaps enough delta-v for lunar orbit (>1200m/s). Granted, once you orbit the Moon, docking with other gear you'll need to land becomes possible (FH's flyby mode doesn't help at all). Anybody have RSS/RO loaded and a good falcon heavy model? Jiggle the parts around and what adding another stage will do...

Remember that you only need high TWR for liftoff, and even less once in orbit. I'd assume that you could launch full stages to be delivered to what ever point you needed and light (and stage them) once docked. Using entire stages will require shipping an engine with each stage, but again they are low TWR and shouldn't take up too much mass. In return, this system should considerably reduce complexity and require less testing in orbit.

Animals that were easy to train became domesticated (there are depictions of people trying to domesticate jackals and cheetahs on pyramids, they tried everything over the years), those that weren't either remained wild or were driven to extinction. Some dinos are believed to have extreme growth rates. Depending on how much food they need (not a problem on a new colony), they might make excellent food livestock. Parrots and covids are some of the most intelligent life on Earth, so you might get some intelligent dinosaurs out of the mix. Which leads to a startling suspicion that the asteroid and other issues weren't the cause of the end of the dinosaurs, but the effects of dinosaur civilization collapsing (presumably they were mining an iridium asteroid in M/LEO and then couldn't keep it up indefinitely). Even if such were possible, the assumption would be that you wouldn't find such a society (unless it was in near stasis) because of how short it would live (or possibly just leave the planet).

As of April, NASA is paying for Moonship (or whatever they call the Starship that lands on the Moon) development. Presumably construction, testing, and plenty of launches if the program lives that long (I suspect 1-2 landers are expected to be culled early, and Starship looks like a comically overpowered lander). Don't forget that Falcon 9 is sucking up most of the money spent on commercial space launches (US DoD still loves its military-industrial complex partners, presumably now including Northrup-Grumman, Russia and China also like their own rockets for both military and commercial use). That is a lot of money, and Spacex isn't paying a lot of money to develop Falcon 9 anymore. I'd like to believe that if your SRBs are supplementing a liquid rocket, then the liquid rocket can provide thrust variation (either by gimballing or with multiple engines selectively throttling). At some point, that's probably not enough, especially if your SRBs are providing nearly all the thrust and are positioned further from the center of mass (such as the Shuttle).

It is really weird that a second stage would not only have TWR>1, but TWR>1 while dealing with suboptimal nozzles. Of course the Mars edition will need a TWR>~1/3 just to lift off Mars, but that is a special case (and the MoonShip needs even less), but even a TWR of 1/3 seems high for a second stage. Astronaut-level safety seems to imply some sort of LES, unless they are really willing to limit themselves to Shuttle-level safety (I can't imagine NASA going along with that). SpaceX *might* quickly prove astronaut-level safety if they can reasonably prove that the Starship *usually* lands and that it can do so even if the vacuum engines fail (so it could abort to land in case of either stage failing, but not both [assuming the vacuum engine can get the thing free, which sounds weird to me]). They'd have a lot harder time getting passengers to Mars if they lose an astronaut crew...

I teleported home last night with Ron and Sid and Meg, Ron stole Meggy's heart away And I got Sydney's leg. - It is a sci-fi thread after all.

Looks like some information was passed to Boeing. Which was always a pretty good guess for this type of thing. https://www.washingtonpost.com/technology/2020/06/20/nasa-boeing-bid-probe/ (not sure which thread this belongs, but found the quoted text in this thread...).

On the level 4 runway, should it be "flat" like the level 1-3 runways? My understanding is that current runway doesn't follow the curvature of Kerbol, but is essentially a straight line. Presumably this is a Unity thing, but extending it might mean that things on the end of the runway will want to roll to the center (or you could even exaggerate this resulting with an effective ramp at the end. It isn't like spaceplanes are going to land from the East).

First, that's not necessarily efficient. For a trip from Kerbol to Duna, you would want to Pe kick [Mangalyaan manuever] from low Kerbol orbit to nearly escape velocity (900m/s), then burn the last (~100m/s) in roughly one last orbital pass (you might have to raise your orbit for the last pass). Killing your velocity at Duna might take a long time, but you certainly shouldn't be burning (either way) at the half way mark. If you are using ions, then you will likely be stuck with continous burns, but still you will stop far before the half-way point. The halfway flip and burn is the hallmark of torchships, which are the antithesis of efficiency but as fast as possible. Kerbal alarm clock is probably the most important mod you will need, and I'd augment it by using multiple fuel tanks set up to only use a set amount of fuel (you'd need to calculate the delta-v you want and pump that much fuel into the tanks set to supply fuel). Then set physical warp to maximum and wait for your alarm clock to ding. Note that this works better with the ion/continous burn. Multiple pe kicks are going to be even more boring. KSP doesn't really want to reward efficiency, even though that appears to be an overall goal...

The biggest issue with ion craft is that that they aren't compatible with the "timewarp" system. They need to be able to put ion craft "on rails", and I can't see that happening on KSP1.x (hopefully they will manage it with KSP2, if it ever ships).

The test articles (and anything point-to-point) will be able to do that, but I'd be shocked if it was really designed to have a TWR>1 once fully fueled. Not that I really know how you could dump propellant, but I assume that it would be necessary during an abort.

Without mods, the physics engine fights you every step of the way (in recovering rockets). I pretty much burned out my original play of KSP due to excessive reuse, and quit for some time. To reuse a booster there are two strategies: 1. Use a low fuel/high thrust to get a bunch of delta-v, then return before you leave the physics bubble. I found this next to impossible, but later the physics bubble increased and it might be possible. 2. Have enough extra fuel so that the booster can "SSTO*" after detaching the upper stage. I almost certainly used SRBs with this, but the center booster was valuable enough I wanted to recover it. Loft both first and second stages high enough they don't get deleted by the physics engine. Switch between the two rockets (don't count on "[" and "]" working, you'll have to mouse fast) and bring both to orbit. Then return the booster to as close to KSC as you can (without breaking it). At this point vanilla KSP is pushing you to a spaceplane that only works thanks to a lot of design choices based around rockets that KSP spaceplane engines easily break. I strongly recommend mods if you want to deal with recovery, and would go so far to recommend "stage recovery" type mods if you ever feel recovery is getting tedious. * Note this is much closer to saying "Falcon 9 boosters can SSTO" than what is normally meant by SSTO. You are bringing zero payload to orbit, and just giving an otherwise empty shell the delta-v it needs for a minimal orbit (to keep the physics engine from deleting the thing and giving you the chance to land somewhat near KSC after going around the planet once). You can presumably skip this if you are willing to land far, far East of KSC and getting your payload to orbit quickly enough.

If you have an ejectable crew pod, I'd make sure that it is fully capable of re-entry and use that to return from orbit. By the time Starship fails a landing attempt, it probably requires more delta-v than an ejectable pod would have. The idea of using SRBs to detach Starship would be for routine launches with many passengers (and obviously only works for booster failures). For a Starship failure, I *think* that the engines to orbit and the landing engines are different (and almost nothing is frozen in Starship's design). They still will require quite a few common parts, but perhaps they can either be reliable or redundant (preferably both) to use for both orbit and abort. Since the abort motors should only fire for a few seconds, they shouldn't be all that heavy. After that you can light the raptors (presumably you'd light both, cutting down on the thrust you'd need on the abort motors). I've already said I don't like the idea of landing on Starship at all (at least until *all* the bugs are worked out), and would far prefer to land via Dragon for the first >>100 landings (Falcon 9 boosters failed to land on launches 81 and 83 after a string of successes).

Wouldn't a LES for Starship just need enough thrust for Starship to detach and leave Super Heavy Booster (or whatever they call stage 1)? Enough high-boost short-duration SRBs should do the trick, and then Starship should be able to land on its own (it might have to dump propellant before landing).

This assumes you have anti-matter, but can't afford to use pure antimatter drives. It also ignores other possible ways to ignite a fusion explosion (laser ignition being the obvious one). But any way to reduce the pulse of a pulse drive should allow a decrease in the mass and complexity of the pusher plate, and that is a good thing. KSP doesn't have much in the way of specific fuels. We have fuel, oxidizer, monopropellant, and solid. RSS/RO has a bunch of real fuels, but I think limits them to proven examples. My old take on the fuels (what we thought each one was):

You mean that real rocket scientists share one of my most annoying KSP design failures?

Then it is a windows issue. And not just a windows issue, because it seems the entire software world has followed them into the "data is executable and executables are data" trap (see "move fast and break things"). So don't connect windows to any network that you want to be secure. Second, if you are the CIA (or NSA), any computer connected to a network is no longer secure. After that you can get into the basic problems that anybody should have to follow...

Vladimir Komarov (Soyuz 1) had to heroically deal with life threatening failure after life threatening failure, solving them all to return from orbit. Unfortunately, there was nothing he could do about failed parachutes...

Depends on the rocket-plane. Shuttle didn't have a great record. X-15 did slightly better (similar number of missions and only one loss of life/crew and vehicle), but the sample sizes are too small to be significant. It might well be easier to improve retropropulsive landing than increase the safety of a spaceplane.

As far as I know, the plans are to build the miniature first. I think they claim to be building it now, but I suspect that "building" includes some very preliminary design...

So the big question is how much does the engine mass, and will you need some form of booster to get you off the ground...

Building a wind tunnel capable of testing a SCRAMJET is possibly as impressive as most of the feats needed to build this engine. The variable nozzle is another breakthrough. The shuttle's "works from sea level to vacuum" is impressive, but something efficient from sea level to vacuum would be far more so. Presumably it would obsolete any aerospike... Plenty of the hype listed seems overrated for such an exorbitant bit of technology. Also I'd wait and see what type of mass ratio they need for the SSTO: this TBCC engine might have the Isp for SSTO, but it still in the wrong place (early in flight instead of late). I suspect spacex's (use 2 stages and recover at least the more expensive one [you'll obviously need both to beat the SSTO]) method will be more effective for a long time. I still suspect it is propaganda, but perhaps they took a page from the Russian/Soviet program and kept a massive leap forward secret until they fully leapfrogged their rival beyond any means of quickly catching up.