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Correct_Inspection25 t1_j6aef8r wrote

SLS was always a place holder until the Obama commercial flight program investments for near earth exploration fully established themselves with their focus on self sustaining privatized profitability. SpaceX is awesome and should be celebrated for its speed, but so far seems to repeat the same missed self imposed overly ambitious timelines even with 50% NASA funding. Remember 6-8 years ago, SpaceX predicted that BFG and Red Dragon would be human rated and ready for deployment in 2020. It’s now 2023, BFR and Red dragon have been completely abandoned for Starship. And in 2023, with billions of NASA co-funding, SpaceX hasnt finished a test crewed vehicle, LSS, new lunar landing thusters, and are expecting to have a successful test launch this year to get to LEO, so figure SLS as something for SpaceX/commercial crewed systems to profit from, it has proved out the new high efficiency lunar injections, started the process of scouting base locations and new rad hardening technologies and permanent lunar presence locations SpaceX and others will use.


OlympusMons94 t1_j6akuun wrote

Once again, Starship delays are irrelevant. It isn't and wasn't ever needed as a launch vehicle for a Moon program, nor was SLS. SLS/Orion, or whatever launch vehicle and capsule are used for Artemis, can't do anything useful until they have a working lander, however long that takes. But once Starship HLS is ready, you might as well make the most of it and replace SLS/Orion. (No other proposed HLS is nearly as far along as Starship, or even under contract to NASA yet. But the same could apply to most any hypothetical HLS, given all of the work that is left to it because of SLS/Orion's shortcomings.)

But since you insist: Orion has been in development since 2006, and SLS since 2011. SLS was based on the earlier Ares and Shuttle. Engines are arguably the most difficult part of a launch vehicle. The core stage engines and boosters for SLS were developed in the 1970s. The upper stage is a repurposed Delta III/IV upper stage using an improved version of an engine first developed in the 1950s. After all of that, SLS still flew nearly 6 years after, and cost twice as much as, what was originally planned.

Starship is a brand new and revolutionary vehicle and should be expected to take longer than SLS to develop. The earliest mention of anything like ITS, BFR, or Starship by SpaceX goes back only to 2012, and even mention of hydrogen fueled "Raptor" engines only goes back to 2009 (since 2012, the fuel has been methane). A Starship design similar its to current form (e.g., switching from carbon fiber to stainless steel) didn't even start until late 2018.

Despite all of that, Starship should make its orbital flight well within a year of SLS. The HLS Starship will of course be extra/different, but that was not contracted until 2021, and even then was delayed (at least on the NASA side) by Blue Origin. Orion has yet to fly with a full life support or any docking systems. SLS will still be using its "interim" upper stage through Artemis III.

I'm not sure what the fixation with radiation hardening is. SpaceX and others have all the access they need to NASA'a data and work on radiaiton. (Furthermore, resillience to radiation is also simpler to brute force with the mass and redundancy afforded by Starship.) SLS itself (and Dragon and Starliner) are not operated beyond LEO, so that is no more an issue than for any other rocket (or LEO capsule). Only Orion (or, as I am proposing a second HLS) and the HLS need to be designed for the deep space environment. Yet again, until the HLS is ready, no one from NASA is landing on the Moon. So even supposing it takes 20 years to get a radiation-hardened HLS, that won't change anything. Whenever the HLS design is ready, we might as well use it for all of Artemis' beyond LEO flight.

The funding models for SLS and Starship are also very different. NASA funding for the HLS is milestone based, and only paid after completing previously agreed upon milestones. SLS is funded in advance through Congress (often getting more than the administration requests). All of Boeing et al's costs are paid for plus a bonus, i.e. cost plus. (In theory, their poor performance should nix the plus part, but that didn't happen.)

Edit: typos


Correct_Inspection25 t1_j6ambib wrote

Hey I love all the money invested in the commercial flight program and the possibility of 100 tons to LEO in a fully reusable vehicle even if it looks like it will take as long as the SLS to develop and test. Me pointing out Starship starting in 2015 and launching a fully crewed rocket and landing it reusably in 2023 is a compliment [Edit: Looks like Elon says crewed test launch of starship wouldn’t be until 2025 most likely but my point still stands]. SpaceX and the odyssey of Falcon Heavy to BFR and Red Dragon to Starship was great, just saying SpaceX steps on its own toes like NASA did when over promising timelines on unproven technology and manufacturing, and the public misses how much they truly moved the ball forward. Two steps forward, one step back and all that. My argument was with the statement that 3-4 day transit to lunar orbit with even a Block I SLS payload would never have worked with Falcon Heavy and it looks like the press and NASA asked SpaceX the same question and the response a few months later with scrapping Falcon Heavy and Red dragon completely for Starship’s 150ton and later once the raptors were proven, 100 ton to LEO platform which will meet SpaceX’s original price per kg/LEO goals back in 2014 or beat them.

SpaceX has had access to NASA’s data on hypersonic active cooling systems for decades, but it didn’t stop them from spending several years of Starship R&D on ablative cooling before abandoning it. I can’t explain the SpaceX admin avoiding building flame trenches and shockwave deluges systems for the largest rocket ever built when China, India and USSR all followed NASA’s Saturn V lead. All I can guess is they are gonna do what the executives want the engineers to do, and in that order. Good news is after all the partial fire pad damages in Starbase, SpaceX last week is shipping deluge and flame trench equipment on barges to Starbase hopefully before the full test.


OlympusMons94 t1_j6arh8y wrote

I fail to see what crewed launch/landing of Starship from/on Earth with crew has to do with anything I said. Or for the most part, Falcon Heavy going to the Moon either. Once the upper stage, be it Falcon's or ICPS, performs the TLI burn in LEO parking orbit, its job is done. They don't need to do anything at or near the Moon.(Perhaps you mean Dragon launched by FH, but I'm not suggesting that either.)

What I am saying is that you can't land people on the Moon without a moon lander, which is a spacecraft capable of supporting humans in deep space. SLS and Orion being ready first or not doesn't change that. Between the generic Moon lander requirements, and the requirements imposed on the HLS (by waiting in NRHO for Orion then going back and forth from there to the surface), the HLS must be a very substantial spacecraft.

If the HLS Starship is capable of supporting humans in NRHO and to and from the Moon, it is just as capable of supporting humans in space between LEO and NRHO. The delta-v required to go from LEO to NRHO and back to LEO is much less than required by the actual lander. So a spacecraft identical to the HLS could serve as the ferry between LEO and NRHO. We already have capsules capable of taking crew to and from LEO, and docking with spacecraft (be it the ISS or the HLS copy). Therefore, by the time the HLS is ready and SLS/Orion have a use, SLS/Orion could be replaced by a copy of the HLS and currently existing vehicles.


Correct_Inspection25 t1_j6asw5t wrote

HLS depends on LSS and a number of other starship tests beyond LEO, without at least LEO, I am curious how SpaceX will show NASA the HLS starship and in orbit refueling will be ready. You should definitely read the 1970 SLS NASA detailed proposal, it was close to that. It used the MULE/NERVA with 500-1000s ISP that had been tested on the ground and ready for the TLI dedicated lunar presence. There was a shuttle for LEO transfer (sadly dropped to the side of the tank and landable boosters were cut in the abandonment of the space race in 1972), situated on the top of a heavy lift booster, both of which reusable. Sadly it was cut due to the fact the Nixon administration considered the space race won, and the research and development money was better spent on Vietnam.

I don’t really care who wins, just that cost plus contracting is abandoned, and we keep the speed up now we have a Cold War like space race motivating politicians, and the western funding of human presence in deep space flowing to as diverse a basket of opportunities as possible.