mxaxai wrote:The main problem is manufacturing cost and complexity, and since politics decided that this was acceptable, the RS-25 is an obvious choice.
Obvious and only choice…
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mxaxai wrote:The main problem is manufacturing cost and complexity, and since politics decided that this was acceptable, the RS-25 is an obvious choice.
Avatar2go wrote:Scrub today, due to inability to heal the hydrogen leak in the core stage and umbilical. That's a major disappointment for them.
zanl188 wrote:
Hydrogen leaks, unfortunately, were not unexpected. Shuttle had numerous issues with LH2 leaks.
Makes me wonder how similar are the shuttle and SLS tail service mast quick disconnect designs?
Aquila3 wrote:Just a side question.
Why do you say smallest KNOWN atom?
Even if you hypothesize by absurd a smaller one would exist it will then not fit the definition of atom anymore...
Avatar2go wrote:Here is a Twitter thread of appreciation for the media, from one of the astronauts who works with them. She rightly points out that most of the media work really hard to bring information about NASA to the public, without bias or negative commentary.
https://twitter.com/AstroAnnimal/status ... 5057505282
Vintage wrote:In other words, the media is a cost free cheering squad. I believe that the Artemis should be melted down for what ever scrap metal value it has.
NASA needs to get out of the rocket ship manufacturing business. The Space Shuttle was a dog and so is Artemis.
Avatar2go wrote:Fortunately the people who are knowledgeable and make the decisions, have a better opinion.
The media reflects public interest in the program, as also indicated by the crowds. A few outlets are exceptionally critical of NASA, as you obviously are as well, but they are decidedly in the minority.
Vintage wrote:I remember the Space Shuttle fanatics back in the day - I was pretty neutral.
Looking back on it, everything the Space did could have been done better and cheaper than the Shuttle.
It's the same with Artemis, the Starship can do it all dependably and more for far less money.
And there are a half a dozen others in the wings.
Vintage wrote:Looking back on it, everything the Space did could have been done better and cheaper than the Shuttle.
BEG2IAH wrote:Vintage wrote:Looking back on it, everything the Space did could have been done better and cheaper than the Shuttle.
And where do you think all the current knowledge came from so that we can look back at the past? I find your statement sad and fairly uninformed.
Here are some of the examples what various orbiters delivered over time:
Compton Gamma Ray Observatory (CGRO) 37,000 lbs
Chandra X-ray Observatory 50,222 lbs (whole payload)
Hubble Space Telescope 24,490 lbs, launch plus 5 servicing missions
ISS - Unity (Node 1) 26,224 lbs
ISS - Destiny (US Laboratory) 32,000 lbs
ISS - Harmony (Node 2) 31,500 lbs
ISS - JEM Pressurized Module (JEM-PM) 35,100 lbs
ISS - Tranquility (Node 3) 42,000 lbs
ISS - trusses and solar arrays (servicing done using robotic arms was only possible using orbiters)
Tracking and data relay satellites
Spacelab - 22 missions
Spitzer Space Telescope
Galileo
Magellan
Ulysses
Mir Docking Module
And which other vehicle could bring back to Earth up to 35,000 lbs of payload? I mean since you are looking back anyway?
Avatar2go wrote:
The current RSRMV SRB has only marginal improvements over the shuttle era, because of the need to use up the existing inventory. The follow on BOLE, which is based on the OmegA, is significantly improved. It has composite casing, which means it carries much more propellant for the same weight, with lower cost. The propellant is a modern HTPB formulation, that is tuned to modulate output, so as to more efficiently utilize the RS-25 (no more throttle back at Max-Q). It has an improved all-electric motor section which greatly increases both thrust and vectoring control (no more hydrazine). The nozzle assembly has a much greater expansion ratio and resultant specific impulse. All new avionics as well.
Avatar2go wrote:
The $4B launch cost is disputed by NASA, and in any case is only the first development & test flight cost. NASA estimates the initial true incremental cost at $2B, with that decreasing to around $1B as the program reaches maturity.
kitplane01 wrote:
Math says max efficency is to carry the highest ISP fuel the highest, and burn the lowest ISP fuel as close to the ground as possible. Therefore the LOX+H engines *should* be the ones to throttle back, and the SRBs should be at max power.
Even better, project total costs over some reasonable number of launches. " NASA's spending on its Artemis program, which aims to establish a sustainable human presence on and around the moon by the end of the decade, is projected to reach a total of $93 billion by 2025, according to a new audit by the NASA Office of Inspector General (OIG)." -
JetBuddy wrote:The Artemis program / SLS has access to 16 RS-25 engines from the shuttles. Which means there will only be 4 SLS launches. Or am I wrong? Will there be additional RS-25 engines produced?
Vintage wrote:Looking back on it, everything the Space did could have been done better and cheaper than the Shuttle.
Avatar2go wrote:JetBuddy wrote:The Artemis program / SLS has access to 16 RS-25 engines from the shuttles. Which means there will only be 4 SLS launches. Or am I wrong? Will there be additional RS-25 engines produced?
Yes, in the refurbishment contract for the 16 shuttle engines, NASA included a request for Aerojet to restart the production line with new tooling and manufacturing methods
...
So the new engines will need to be ready by Artemis 4. They are pretty far ahead of schedule on that.
Avatar2go wrote:JetBuddy wrote:The Artemis program / SLS has access to 16 RS-25 engines from the shuttles. Which means there will only be 4 SLS launches. Or am I wrong? Will there be additional RS-25 engines produced?
Yes, in the refurbishment contract for the 16 shuttle engines, NASA included a request for Aerojet to restart the production line with new tooling and manufacturing methods, with the option to produce up to 6 new non-reusable & upgraded engines, for certification, testing and eventual flight.
Then in a separate contract, NASA expanded the order from 6 to 18 additional engines, with further performance and manufacturing improvements. There is expected to be a third add-on order eventually, for a future third generation engine.
The NASA policy is that 2 spare engines must be on-hand for contingencies in every launch. So the new engines will need to be ready by Artemis 4. They are pretty far ahead of schedule on that.
Avatar2go wrote:kitplane01 wrote:
Math says max efficency is to carry the highest ISP fuel the highest, and burn the lowest ISP fuel as close to the ground as possible. Therefore the LOX+H engines *should* be the ones to throttle back, and the SRBs should be at max power.
The efficiency of the stack is the combined efficiency of the engines. For traditional staging, you fire all one, then all the other, they don't overlap. With Shuttle/SLS, they fire simulataneously so you can optimize the thrust trace for the combination. The Shuttle used throttling of both at Max Q, because the SRB was unable to absorb the entire throttle. For BOLE, the design can be optimized to absorb the throttle. This results in higher efficiency of the stack. Here is an article that is explains what was done in optimizing the design:
https://www.nasaspaceflight.com/2021/07/sls-bole-srbs/
Avatar2go wrote:Even better, project total costs over some reasonable number of launches. " NASA's spending on its Artemis program, which aims to establish a sustainable human presence on and around the moon by the end of the decade, is projected to reach a total of $93 billion by 2025, according to a new audit by the NASA Office of Inspector General (OIG)." -
You have to consider what is covered by the $93B. It includes all development, ground systems, telecommunications, control room, crawler, mobile launchers, and other indirect support costs. In terms of direct flight costs, it includes the Orions, the core stages, the boosters, the landers, the rovers, the spacesuits, the Gateway station, the CLIPS missions, and all the lunar robotics, cubesats, and satellites, through the year 2030.
The $93B is a little more that one third the cost of the Apollo program at $250B, but Artemis is a far more complex and robust exploration program than Apollo.
This is where the media reporting often fails, and even the OIG reports can be misleading. And why they are disputed by NASA. The OIG finds and accounts every cost that can be feasibly charged to Artemis. It's fine to do that to determine an upper bound on total program cost. But if you look at the incremental cost to actually launch a mission, it's far less.
There's an analogy for the F-35, which is often described as the most expensive fighter program ever, at $1.6T. But the incremental flyaway cost of an F-35 is actually lower than other recent fighters, at between $80M and $100M. So it's misleading to characterize it that way.
kitplane01 wrote:
I really wonder if the $93B (and more coming) costs of Artemis could have gotten better science by spending it elsewhere.
kitplane01 wrote:
Second, I politely disagree with how you do math. For the F-35, development costs *should* count. For Artemis, development costs *should* count. And if it's purpose is to put humans on the moon, then the cost of a lunar-rated space suit also counts. Even though NASA plans to spend an astronomically large amount on the suits, they are a small cost for the program as a whole.
I really wonder if the $93B (and more coming) costs of Artemis could have gotten better science by spending it elsewhere.
Avatar2go wrote:kitplane01 wrote:
Second, I politely disagree with how you do math. For the F-35, development costs *should* count. For Artemis, development costs *should* count. And if it's purpose is to put humans on the moon, then the cost of a lunar-rated space suit also counts. Even though NASA plans to spend an astronomically large amount on the suits, they are a small cost for the program as a whole.
No one is disputing that development costs "should" count. The point was that for aircraft, the flyaway cost is also an important metric. Just as the incremental cost is an important metric for rockets. And that Artemis is paying for a ton of assets besides the rocket.I really wonder if the $93B (and more coming) costs of Artemis could have gotten better science by spending it elsewhere.
We can never know the answer (the path not taken) but Musk is saying Starship will require $10B in investment, and that is increasingly looking to be a conservative estimate. And that is for one vehicle, attaining LEO, without the other assets that Artemis provides, and without human rating.
I think the argument of "what could have been done" is one of the fallacies surrounding NASA & the Artemis program. There is value in maintaining proficiency at NASA and in the "old-space" vendors. The idea that all that work could have been turned over to one or two "new-space" vendors, is absurd. It wouldn't be possible even today, much less a decade ago.
I'm actually all for "new-space" and wish them every success. I also believe that NASA will continue to hand over programs to the commercial sector, as they can demonstrate that two robust responses become possible. That has been the pattern and I'm sure it will continue. Eventually the old and new will blend into a competitive market, that has been fostered and supported by NASA. Who will remain in the business of exploration, which is their mission.
But the premise that this could be done today, or years ago, is just not valid. The people who claim that, don't understand the financial & engineering contributions that NASA is making to the new-space programs. They are very significant.
kitplane01 wrote:
No one I've met knows the future ... but I think one can make a strong argument that for NASAs launch system "burn it to the ground and contract everything to ULA/SpaceX" would be exactly right. I'd wonder if you would get twice the speed at half the cost.
SLS (which is the thing making the news now) was supposed to cost $10B, incremental cost $0.5B per launch, and require 7 years. It's now at $25B, $2B per launch, and 12 years. I think SpaceX could do better, and I *hope* ULA could.
SpaceX's Starship is to be fully reusable, and no one thinks they spent $25B to develop it. Also, arguably it began serious development in 2017, and 5 years later they have a prototype.
Question: Would you rather have Starship with it's development costs and timeline, or SLS with it's development costs and timeline?
Avatar2go wrote:kitplane01 wrote:
No one I've met knows the future ... but I think one can make a strong argument that for NASAs launch system "burn it to the ground and contract everything to ULA/SpaceX" would be exactly right. I'd wonder if you would get twice the speed at half the cost.
I believe this argument is largely based on misunderstanding of the industry. At the time SLS was conceived, there was no commercial entity that could have undertaken the project. As I mentioned, it's a fallacy that has taken root amongst Musk supporters, but Musk himself does not make this claim.
Avatar2go wrote:kitplane01 wrote:SLS (which is the thing making the news now) was supposed to cost $10B, incremental cost $0.5B per launch, and require 7 years. It's now at $25B, $2B per launch, and 12 years. I think SpaceX could do better, and I *hope* ULA could.
These are fair criticisms, apart from the fallacy regarding SpaceX/ULA capability. But if you tell the whole story, the program changed direction with each administration, except the current one. And was consistently funded at $2B - $3B per year for most of its development life. Of the $93B you quoted, the majority occurs in the last 3 years after launch operations have begun.
The issue that arises with flat funding, is that you extend and inflate labor and facility costs, in return for a predictable budget. If there are delays, which there always are in all space programs, those costs accumulate because you can't divest expertise or shut down buildings during the delay. Even if the delays are non-technical, like COVID & storm damage.
Avatar2go wrote:kitplane01 wrote:SpaceX's Starship is to be fully reusable, and no one thinks they spent $25B to develop it. Also, arguably it began serious development in 2017, and 5 years later they have a prototype.
This again is a misunderstanding. The design goal of SLS is to maximize characteristic energy (C3) delivered to a given payload on orbit. Starship design goal is reusability. These are opposing trade constraints for any rocket. SLS gives up reusability for C3. Starship gives up C3 for reusability. Musk has not invented new physics, or knowledge that NASA doesn't have. That is another of the fallacies. Both are accountable to the rocket equation.
The consequence of this is that SLS needs no other supporting infrastructure. It can send payloads on direct trajectories within the solar system, in a single launch. That was the intent. In contrast, Starship cannot send a payload out of earth orbit, because it lacks C3.
To get around this limitation, Starship requires orbital refueling, an infrastructure that doesn't yet exist. With sufficient propellant addition in orbit, Starship can match the C3 of SLS. To do this requires both an orbital depot, and more than a dozen additional launches of propellant to the depot. So that is at least 14 launches to SLS single launch.
In return for that cost, both Starship and the Super Heavy booster can be reusable. But to be competitive, those launches will need to be below $100M each. SpaceX is not able to do that with Falcon Heavy. In time it may be possible with Starship. But that will also require a frequent launch cadence, and the heavy lift market to support it. That too, does not exist yet.
As stated, I hope that all these things can be achieved, that would be a great benefit to our space capabilities. But they will require significant investment. Given where the Starship prototype is now, I could easily see that investment reaching $20B to $25B, to build out & maintain the Starship & orbital refueling infrastructure, in a safe and reliable way.
kitplane01 wrote:Avatar2go wrote:kitplane01 wrote:
No one I've met knows the future ... but I think one can make a strong argument that for NASAs launch system "burn it to the ground and contract everything to ULA/SpaceX" would be exactly right. I'd wonder if you would get twice the speed at half the cost.
I believe this argument is largely based on misunderstanding of the industry. At the time SLS was conceived, there was no commercial entity that could have undertaken the project. As I mentioned, it's a fallacy that has taken root amongst Musk supporters, but Musk himself does not make this claim.
We didn't communicate right.
I'm not saying "In 2010 SpaceX could have done this stuff". I'm saying "In 2017 they should have burned it to the ground and started again".
My claim is the ~$12B that has been spent in the last 5 years, if given to SpaceX, could have bought something even better than Starship.Avatar2go wrote:kitplane01 wrote:SLS (which is the thing making the news now) was supposed to cost $10B, incremental cost $0.5B per launch, and require 7 years. It's now at $25B, $2B per launch, and 12 years. I think SpaceX could do better, and I *hope* ULA could.
These are fair criticisms, apart from the fallacy regarding SpaceX/ULA capability. But if you tell the whole story, the program changed direction with each administration, except the current one. And was consistently funded at $2B - $3B per year for most of its development life. Of the $93B you quoted, the majority occurs in the last 3 years after launch operations have begun.
The issue that arises with flat funding, is that you extend and inflate labor and facility costs, in return for a predictable budget. If there are delays, which there always are in all space programs, those costs accumulate because you can't divest expertise or shut down buildings during the delay. Even if the delays are non-technical, like COVID & storm damage.
And note that SpaceX doesn't have these problems.
It's not clear if you're saying "It's not NASA's fault" or "Look how messed up the government is". I'm saying which one you pick doesn't matter because either way it sux.
kitplane01 wrote:Avatar2go wrote:kitplane01 wrote:SpaceX's Starship is to be fully reusable, and no one thinks they spent $25B to develop it. Also, arguably it began serious development in 2017, and 5 years later they have a prototype.
This again is a misunderstanding. The design goal of SLS is to maximize characteristic energy (C3) delivered to a given payload on orbit. Starship design goal is reusability. These are opposing trade constraints for any rocket. SLS gives up reusability for C3. Starship gives up C3 for reusability. Musk has not invented new physics, or knowledge that NASA doesn't have. That is another of the fallacies. Both are accountable to the rocket equation.
The consequence of this is that SLS needs no other supporting infrastructure. It can send payloads on direct trajectories within the solar system, in a single launch. That was the intent. In contrast, Starship cannot send a payload out of earth orbit, because it lacks C3.
To get around this limitation, Starship requires orbital refueling, an infrastructure that doesn't yet exist. With sufficient propellant addition in orbit, Starship can match the C3 of SLS. To do this requires both an orbital depot, and more than a dozen additional launches of propellant to the depot. So that is at least 14 launches to SLS single launch.
In return for that cost, both Starship and the Super Heavy booster can be reusable. But to be competitive, those launches will need to be below $100M each. SpaceX is not able to do that with Falcon Heavy. In time it may be possible with Starship. But that will also require a frequent launch cadence, and the heavy lift market to support it. That too, does not exist yet.
As stated, I hope that all these things can be achieved, that would be a great benefit to our space capabilities. But they will require significant investment. Given where the Starship prototype is now, I could easily see that investment reaching $20B to $25B, to build out & maintain the Starship & orbital refueling infrastructure, in a safe and reliable way.
Actually I already knew all this (though its nice to be reminded).
Lets suppose both work as intended (though I doubt SLS will ever be reliable or on it's newer, even more inflated budget).
Starship builds something we've never had before. It's both reusable, and large enough to get human capsule sized payloads (with refueling) out of earth orbit. Starship gets us closer to a future we want: cheaper access to deep space. SLS is reusing a bunch of existing tech to make a newer Saturn V.
I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship.
I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship.
Avatar2go wrote:kitplane01 wrote:Avatar2go wrote:
I believe this argument is largely based on misunderstanding of the industry. At the time SLS was conceived, there was no commercial entity that could have undertaken the project. As I mentioned, it's a fallacy that has taken root amongst Musk supporters, but Musk himself does not make this claim.
We didn't communicate right.
I'm not saying "In 2010 SpaceX could have done this stuff". I'm saying "In 2017 they should have burned it to the ground and started again".
My claim is the ~$12B that has been spent in the last 5 years, if given to SpaceX, could have bought something even better than Starship.Avatar2go wrote:
These are fair criticisms, apart from the fallacy regarding SpaceX/ULA capability. But if you tell the whole story, the program changed direction with each administration, except the current one. And was consistently funded at $2B - $3B per year for most of its development life. Of the $93B you quoted, the majority occurs in the last 3 years after launch operations have begun.
The issue that arises with flat funding, is that you extend and inflate labor and facility costs, in return for a predictable budget. If there are delays, which there always are in all space programs, those costs accumulate because you can't divest expertise or shut down buildings during the delay. Even if the delays are non-technical, like COVID & storm damage.
And note that SpaceX doesn't have these problems.
It's not clear if you're saying "It's not NASA's fault" or "Look how messed up the government is". I'm saying which one you pick doesn't matter because either way it sux.
I'm saying your suggestion is not feasible, because the capacity to do that still lies in the future. SpaceX has never suggested that they could or should have taken over Artemis. It's purely a fan fiction.
Your assertion that funding does not control the rate of progress at SpaceX is also not valid. Musk himself has said they have to pick and choose the aspects of Starship to push forward, because of limited resources. He has a lot of ideas for improvement, he basically never stops thinking in those terms. But the physical and fiscal reality is that you have to define limits and work toward them. SpaceX does this just like NASA, and just like every other organization.
Avatar2go wrote:kitplane01 wrote:Avatar2go wrote:
This again is a misunderstanding. The design goal of SLS is to maximize characteristic energy (C3) delivered to a given payload on orbit. Starship design goal is reusability. These are opposing trade constraints for any rocket. SLS gives up reusability for C3. Starship gives up C3 for reusability. Musk has not invented new physics, or knowledge that NASA doesn't have. That is another of the fallacies. Both are accountable to the rocket equation.
The consequence of this is that SLS needs no other supporting infrastructure. It can send payloads on direct trajectories within the solar system, in a single launch. That was the intent. In contrast, Starship cannot send a payload out of earth orbit, because it lacks C3.
To get around this limitation, Starship requires orbital refueling, an infrastructure that doesn't yet exist. With sufficient propellant addition in orbit, Starship can match the C3 of SLS. To do this requires both an orbital depot, and more than a dozen additional launches of propellant to the depot. So that is at least 14 launches to SLS single launch.
In return for that cost, both Starship and the Super Heavy booster can be reusable. But to be competitive, those launches will need to be below $100M each. SpaceX is not able to do that with Falcon Heavy. In time it may be possible with Starship. But that will also require a frequent launch cadence, and the heavy lift market to support it. That too, does not exist yet.
As stated, I hope that all these things can be achieved, that would be a great benefit to our space capabilities. But they will require significant investment. Given where the Starship prototype is now, I could easily see that investment reaching $20B to $25B, to build out & maintain the Starship & orbital refueling infrastructure, in a safe and reliable way.
Actually I already knew all this (though its nice to be reminded).
Lets suppose both work as intended (though I doubt SLS will ever be reliable or on it's newer, even more inflated budget).
Starship builds something we've never had before. It's both reusable, and large enough to get human capsule sized payloads (with refueling) out of earth orbit. Starship gets us closer to a future we want: cheaper access to deep space. SLS is reusing a bunch of existing tech to make a newer Saturn V.
I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship.
You are arguing over nothing here. I clearly said that I hope Starship works out, and that we need both options in the long run.
bobinthecar wrote:I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship.
No matter how you spin it ULA is fleecing the government.