Apollo 13 was much more ordered and by-the-book than the movie portrayed. An older crew might have done even better, though I don’t think the crew that was there did any cowboy moves.
Perhaps a better comparison was Apollo 11, where Armstrong had to make a very quick decision about the landing site and did some fine piloting to get it to a clear spot within the narrow propellant margins. Perhaps one could argue that an older pilot wouldn’t be quite as sharp in this respect.
But experience counts, too. Captain Sullenberger also made some rapid decisions and did some fine piloting to get Flight 1549 down safely, and he was 58.
At any rate, none of this applies to modern capsules, which aren’t piloted in any meaningful way. If something goes wrong, the capsule will abort the mission on its own. If that goes wrong, then the ground support will abort the mission. And if that goes wrong, then the crew presses the button and aborts that way. There’s just no room for duct-taping or dead-sticking their way to a solution unless the issue is so minor that it doesn’t warrant an abort at all.
I don’t think so, helium pressure tanks seem to be ubiquitous in rocket designs. My guess would be that the engineers want to make sure the propellent tanks maintain a constant pressure as they’re emptied.
The article says it’s related to the reaction control thrusters on the service module, which would be pressure-fed. They’re small and simplicity is preferred over max performance, so pressure-fed is fine.
Main tanks are also generally pressurized for structural reasons, and to keep some head pressure on the engine intakes. But the leak here is from the payload, not the rocket.
The Crew Flight Test of Boeing’s Starliner spacecraft is no longer targeting Saturday, May 25. We’re awaiting official word from NASA and Boeing on the next possible launch date and for more information regarding the path forward on the helium leak.
A scathing criticism of the Artemis/ Gateway program:
The author complains that SpaceX doesn’t have much time to develop the lunar lander version of its Starship rocket. That may not be a problem if Starliner experiences much more in the way of delays.
I’m onboard with a lot of what he says, but there are some odd statements in there. For example:
And yet in the end this single-use lander carries less payload (both up and down) than the tiny Lunar Module on Apollo 17.
HLS can carry 100 tons to the lunar surface. The Lunar Module was <1 ton. How much it can bring back remains to be seen but is undoubtedly more than the LM. The return mass will be limited by Orion, not Starship.
The refueling phase will be a challenge and demands that SpaceX reach a high flight rate quickly. And the author acknowledges that SpaceX more than anyone is best equipped to do this. But I think he’s wrong for making analogies with other heavy-lift systems or the time it took to reach a high cadence with Falcon 9. Starship is designed from the beginning for rapid reusability and takes into account all the lessons they learned previously.
The 15 refueling flights will not be the case forever. It might require that many for the first version, but they have already demonstrated some of the improvements needed to reduce that (in particular, performance of the Raptor engine).
I was wondering where the author got that as well. Does it have anything to do with going to/from the nearly rectilinear halo orbit and back instead of low lunar orbit or direct landing? Or is it a peculiarity of the variant that will be used for Artemis?
From the article “You don’t have to be a rocket scientist to wonder what’s going on here. If we can put a man on the moon, then why can’t we just go do it again?”
IANA rocket scientist so without that knowledge or expertise, I’ve often wondered about this. Superficially, without any analysis, the existing development process seems incredibly counterintuitive somehow and, as I’ve seen in various places, I suspect is hugely a function of politics and economics setup to distribute funding to as many electoral districts and corporations as possible.
Intuitively (to me anyway), it would have made much more sense to just “do Apollo” again, except start with a redesigned CM interior, taking advantage of 40 or 50 years of computing improvements and continuing with iterative improvements.
The earth-to-moon transit time consequences of NHRO were interesting and, as the author stated, add an element of risk to version 2.0 of a first manned landing on the moon, which should entail a risk minimalization priority until reliability and safety are established.
Artemis calls the agency’s competence as an engineering organization into question. For the first time since the early 1960’s, it’s unclear whether the US space agency is even capable of putting astronauts on the moon.
It’s as if Ford in 2024 released a new model car that was slower, more accident-prone, and ten times more expensive than the Model T.
When a next-generation lunar program can’t meet the cost, performance, or safety standards set three generations earlier, something has gone seriously awry.
The rocket can only launch once every two years at a cost of about four billion dollars[3]—about twice what it would cost to light the rocket’s weight in dollar bills on fire[4].
Early on, SLS designers made the catastrophic decision to reuse Shuttle hardware, which is like using Fabergé eggs to save money on an omelette.
Originally a stopgap measure introduced to save the Shuttle budget, these heavy rockets now attach themselves like barnacles to every new NASA launcher design.
NRHO is terrible for getting to the moon. The orbit is like one of those European budget airports that leaves you out in a field somewhere, requiring an expensive taxi.
NASA likes to boast that Orion can stay in space far longer than Apollo, but this is like bragging that you’re in the best shape of your life after the bank repossessed your car.
it’s a little bit as if the National Oceanic Atmospheric Administration insisted on keeping bathyscapes full of sailors at the bottom of the sea, irrespective of cost or merit, and kneecapped programs that might threaten the continuous human benthic presence. You can’t argue with faith.
If this accelerating pattern of delays continues, by year’s end we might reach a state of continuous postponement, a kind of scheduling singularity where the landing date for Artemis 3 recedes smoothly and continuously into the future.
I dunno for sure. I would predict that’s part of it, but only in the sense that they use Orion to get back from NRHO and that has limited capability of returning mass. And that NASA doesn’t (currently?) plan on putting a bunch of cargo downmass on HLS. But that’s not a limit of Starship; it’s a limit of their mission plan.
SpaceX should load up Starship with 100 tons of water at least if NASA can’t figure out anything else to do.
“To start with the obvious, HLS looks more likely to tip over than the last two spacecraft to land on the moon, which tipped over. It is a fifteen story tower that must land on its ass in terrible lighting conditions, on rubble of unknown composition, over a light-second from Earth. The crew are left suspended so high above the surface that they need a folding space elevator (not the cool kind) to get down”
So, any Dopers with engineering knowledge, is this as real a problem as it superficially seems? ISTM that there is an inherent tipping risk with something that tall but is that just a layperson’s perception?
One thing that is pretty cool, there are a few websites including JSC and the Lunar Surface/Flight Journal others that have pretty much ALL the documents generated from the 1950s (When it was called NACA) thru the end of Apollo program and you can look through all the design proposals by industry when the government started the bidding process. Everybody wanted a piece of the action, there are lots of different strategies.
Nobody had any firm grasp on the hardware. When direct flights were envisioned, they did anticipate very large rockets landing just as in the Buck Rogers and Space Patrol television shows.
One proposal thought that the rockets should land horizontal, like a plane, probably for this reason. I guess what I’m thinking, one would think they have thought this through thoroughly, since most of the work has already been done long, long ago. Maybe I’m naïve
Maybe you’re not, but they certainly sound like they were. I mean, if you could land in an airless field in Idaho on completely unimproved surface, how the hell are you going to take back off? It’d be like pulling a (quite large) aircraft into a tropical port sans runway and leaving. Sans lights, power, runways, anything. That’s not a flight plan, it’s a crash landing.
