Yes; NASA is in the process of selecting the landing sites now, and a big component is the possibility of water:
They’re all at the South Pole, which has regions of permanent darkness within the craters (allowing the ice to collect). It also has regions of near-permanent light, so elevated, vertical solar panels can provide power for months at a time. I suspect that a nearby pair of locations can provide true continuous power (needed for a permanent base).
Whether this is useful as a “gas station”, I’m not sure. The Moon is still a pretty deep gravity well, and it going down just to refuel seems impractical. Refueling in Earth orbit is likely cheaper. However, refueling on the surface will allow larger and more capable landing systems for the Moon. Starship is big, but it could carry even more payload if it could refuel on the surface (even if it’s only the oxygen).
According to PastTense’s link ^, the last attempt was scrubbed because the
engineers couldn’t be sure that the temp in one of the engines was low enough,
and they thought this was because the sensor was faulty, and that it would be
impractical to replace said sensor …
So … how will they know this time ? Are they going to assume that all engines
will be at the same temperature ?
(also - why was there just one sensor ? There should be at least three of each sensor (in everything that needs a sensor))
May not matter. They are well behind schedule loading propellant. A leak has developed at the quick disconnect for the main 8" line for loading the liquid hydrogen. LOX is nearing completion (87%), but LH2 is just now at 10% and it was supposed to be more or less done more than an hour ago. They’re stuck in slow-fill mode because fast fill is when the leak kicks in.
For comparison, LOX is 196,000 gallons, LH2 is 538,000 gallons.
If not now, very soon this program will be known first, second, and third for scrubbed launches.
It’s a much different information era now than it was for Apollo (needless to say). Are we going to get to the point that “Artemis” becomes shorthand for “Biden initiative that wasted money and never worked”? Fair or unfair.
Did this hydrogen leak stuff not show up during various rounds of testing? Is this hydrogen thing just that fraught? If so, might a better mousetrap be developed? Something that’s just on the bleeding edge of functional (charitably) really needs to be improved before banking on it, right? I know the engineering is a difficult high-wire act, but is this the very best that can be done?
Beginning in April of this year, NASA conducted four separate “wet dress rehearsal” tests during which the agency aimed to fully fuel the SLS rocket and countdown to T-10 seconds, ending the test before ignition of the main engines. Each of these four tests ultimately ended prematurely, although the fourth attempt in June saw engineers bring the rocket down to T-29 seconds.
However, to reach that late stage in the countdown, NASA had to “fool” the flight computer. During the test, a 4-inch hydrogen line—smaller than the problematic 8-inch line on Monday—had a leaky seal. To complete the wet dress test, NASA chose to mask the leak from the ground launch sequencer, the ground-side computer that controls the majority of the countdown.
Because of this masking, NASA could not complete the engine chill portion of the test. Had it done so, the agency may well have uncovered the problem that caused a scrub on Monday. In hindsight, therefore, NASA probably should have completed a full wet dress rehearsal before rolling the rocket out for a launch. Instead, the agency effectively attempted a fifth wet dress test on Monday, when the world was expecting a launch.
As I understand it, there are technically small additional windows available Monday and Tuesday, but realistically, it’s more likely to be mid-to-late October. There’s a SpaceX Crew (5) launch in early October.
According to reports, the SLS program staff are recommending a rollback to the VAB for diagnoses and repair of the leak issues. That would mean that the next attempt would have to be either during the Sep 19-Oct 4 launch windows, but more likely the October 17+ window. Of course, depending on how long it takes them to fix the darn thing.
Yep, back to the VAB it goes. Hydrogen is funny stuff. Lots of power for the weight, but REALLY hard to handle. I’m sorry to say that I’m not sure STS is ever going to be a reliable launch system. This is what we get when politicians, administrators, and industry lobbyists dictate engineering decisions. I just hope we get through the scheduled mission sequence without any human casualties.
Like Artemis, the lower stage of the Saturn V was also powered by liquid hydrogen and liquid oxygen. IIRC, there was reluctance to use LH2 in the first stages of earlier generations of rockets for technical and safety reasons, but by the time the Saturn was designed engineers had more confidence in being able to handle it.
The first stage of the Saturn V was kerosene and oxygen. The second and third stages were hydrogen.
SLS is… a sorta 2.5 stage rocket. There’s a core stage (hydrolox) that’s lit on the ground, an upper stage (also hydrolox), but also a pair of solid boosters that burn out before the core stage. No kerosene.
You’re right, though I seemed to remember it being hydrogen, and indeed Googling for “Saturn V propellant” turns up this:
Stage info
First stage – S-IC
Specific impulse 421 seconds (4.13 km/s) vacuum
Burn time 165 + 335 seconds (2 burns)
Propellant LH2 / LOX
But according to the Wikipedia article that this is supposedly from, it actually says it was RP-1 (a form of kerosene) and LOX. I think those initial results were describing one of the upper stages.
Yeah, that must have been the third stage. You’ll never get >400 s specific impulse with kerolox (i.e., kerosene/LOX, RP-1/LOX). Also, the third stage is the only one that performed two burns (final LEO burn, then the Trans-Lunar Injection burn).
