Avatar2go wrote:

kitplane01 wrote:

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.

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.

IF SLS can send payloads on direct trajectories in a single launch why is it that they need a modified version of Starship to land and return astronauts from the moon? How is Starship getting out of orbit? Do a little research. You will see that the lander is launched in to lunar orbit and only then is refueled for the trip down to the surface and back.

Falcon heavy is already at 97million a launch and it has a TLI capacity of about 22 tons.

bobinthecar wrote:

Exactly.

SLS is an expensive way of getting to the moon. It uses out of date technology to do not much of anything except put a capsule in moon orbit. It cannot even land and return a mission to the moon without a separate lander being supplied by SpaceX. Starship will be able to put in excess of 100 tons in to low earth orbit. In other words the hard work is done. This makes for a much more flexible system. Even a combination of two or three Falcon Heavy launches at 90 million each could accomplish the same as a single SLS launch costing 4 billion. Sure there would be a cost to develop some additional hardware and there would be the need to probably refuel spacecraft but you have the same situation already with SLS anyway.

No matter how you spin it ULA is fleecing the government. Who do you bet on? Before SpaceX ULA did maybe a dozen launches a year. Their Atlas 5 uses Russian engines, costs about three times the price of a Falcon 9 and puts less payload in to orbit. Vulcan is late and it is using engines that are still not ready. In the meantime SpaceX has continually upgraded Falcon9. Fielded Falcon Heavy and is on the cusp of launching a super heavy orbital class rocket. If NASA had spent a fraction of the billions spent on SLS helping SpaceX develop Starship we would be on Mars already.

I'd advise you read the previous discussion, as to why these points about SLS are not really true.

Falcon Heavy is not human rated, and cannot lift the weight of Orion. That was established by NASA some years ago. So that is not true either.

SpaceX was not, and is not, capable of reproducing Artemis. No one at SpaceX has ever made any such claim. As I mentioned, it's pure fan fiction. It comes only from the Internet, and those that don't understand either platform, or the issues involved. As I also mentioned, the two platforms do not compete. You cannot simply toss out SLS, no matter how convoluted or revisionist your argument is.

As things stand now, we will be very fortunate if HLS is ready for it's lunar missions on time, in 2024. The Starship stack has not flown yet. Nothing has been built for HLS. Nothing has been done to demonstrate on-orbit refueling. HLS is still in the design certification stage, so all that work lies ahead.

Already the first uncrewed HLS flight has been scaled back. It will be a skeleton vehicle, no crew module, and will be able to descend to the lunar surface, but not come back. That removes much of the refueling hurdle, but also means the first ascent from the moon, if things stay on plan, will be the crewed demonstration. NASA is not fully comfortable with that risk, but the commercial contract permits it.

Here's the thing though. Rather than criticizing and complaining about SpaceX, NASA is doing what it always does, they are solving the problems and helping out. They are funding under Artemis, several small scale refueling test flights. They have assigned multiple NASA teams to SpaceX, also under Artemis, to work on the refueling, human safety, and ascent problems.

And they are funding a second round of the SpaceX HLS lander, so it can get closer to the sustainable vehicle they really need. And they are funding a second partner lander, so that they have a path forward even without SpaceX, if necessary. Although there is no reason to think it will be necessary.

For those reasons, even though it may be delayed, and require more assistance from NASA, I have confidence that HLS will eventually work. NASA will backstop it, as they always do for all their programs. They won't let it fail.

As far as Vulcan, it's BE-4 flight engines are completing integration testing for the vehicle right now, and they will reach orbit in about the same time frame as Starship and Raptor. So all the noise about that, is also untrue.

There is a ton of misinformation and flawed perspective out there, put forward as if from God himself (or perhaps equivalently from Elon, even though Elon himself does not make any of those claims). Which is both baffling and bemusing to NASA, who have done nothing but support SpaceX, in every possible way. No NASA, no SpaceX. Those are the facts, but somehow they get lost in the Internet maelstrom.

bobinthecar wrote:

IF SLS can send payloads on direct trajectories in a single launch why is it that they need a modified version of Starship to land and return astronauts from the moon? How is Starship getting out of orbit? Do a little research. You will see that the lander is launched in to lunar orbit and only then is refueled for the trip down to the surface and back.

Falcon heavy is already at 97million a launch and it has a TLI capacity of about 22 tons.

So again this is based on misunderstanding. SLS Block 1 is designed to send Orion to the moon. To do that requires the ICPS, which is a payload for the core stage, just like Orion. The combined weight of those is around 60 tons. So no way does Falcon Heavy have that lift capability.

For Orion/ICPS, the core stage has a margin of about 10 tons, that is not used. But will be used on later flights. SLS Block 1B and Block 2, can lift much more, about 100 to 130 tons to LEO. This is because they use EUS, which is a true second stage, unlike ICPS, which is a kick stage.

Thus with Block 1/ICPS, it's not possible to send the lander on the same flight. As noted this is because Orion is a large and heavy vehicle. For Block 2, it was possible, but NASA decided to use 2 launches, which gives them a much larger lander.

The original HLS solicitation required the lander to be launcher agnostic, as Starliner and Cygnus also are. However as with the other commercial programs, NASA waived that requirement for SpaceX, because there is no hope of compability with their hardware.

The notion that Starship can leave orbit without refueling is incorrect. It will need refueling in Earth orbit to get to the moon, and then will be out of fuel after it ascends from the lunar surface. This means to be re-used, it will need refueling in lunar orbit as well. NASA has deferred that capability for HLS, because there was no hope of lunar refueling being ready in the HLS mission timeframe. It will be pushed to the Option B follow-on contract for the sustainable lander.

Lastly for Falcon Heavy, the cost of launching the Gateway modules to lunar NRHO (same destination as Orion with SLS), is $330M. Falcon Heavy is able to break $100M with very small payloads, as a minimum case. But nothing on the scale of lunar missions.

kitplane01 wrote:

I'm saying that you misunderstand. I don't want SpaceX to make the SLS (though I'd be my house they would do a better job than NASA).
I'm saying I want SpaceX to make Starship, or Falcon Heavy ... and if you really want to go to the moon with fragile humans to use Starship. or Falcon Heavy. Don't the waste time and money on the over expensive, way late, fire-dump, repurposed old technology SLS.

SLS gets us to the moon, but is a dead end technologicaly. Both Falcon and Starship moves us toward a future of cheaper access to space, which makes everything including lunar missions better.

At the moment, Starship is still vapourware. Elon has made numerous predictions which all failed to materialise:
Sep 2017: Elon forecasts 2 cargo flights to Mars in 2022 and the first human carrying flight to Mars in 2024
Dec 2019: Elon forecasts first Starship orbital flight in 2020 and a tourist flight around the moon with up to eight passengers in 2023
Dec 2020: Elon forecasts first Starship orbital flight in 2021 and a flight to Mars with latest date to land on Mars by 2026 and and if luck 2 years earlier.
Nov 2021: Elon forecasts a dozen launches in 2022
Aug 2022: Elon forecasts a orbital flight within weeks or up to 12 months later (this is the only one still possible...)
And they started on Starship around 2005.

If SLS had this track record it would have been cancelled.

On the other hand, the Webb telescope was many years late and far over budget, but the results are absolutely spectacular and exceed my wildest expectations. So NASA is not completely incompetent.

Avatar2go

I was hoping that you were going to address these questions.

kitplane01 wrote:

I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship.
Does your long run really include $2B per launch expendable rockets?

AngMoh wrote:

At the moment, Starship is still vapourware.

At the moment SLS is still vaporware.

AngMoh wrote:

Elon has made numerous predictions which all failed to materialise

The arguments against SLS aren't in any way boosterism for Eldon Musk, and aren't about Space X.

For me, it is a question of using last century's technology vs building the future Space program.
SLS is a dead end.

AngMoh wrote:

kitplane01 wrote:

I'm saying that you misunderstand. I don't want SpaceX to make the SLS (though I'd be my house they would do a better job than NASA).
I'm saying I want SpaceX to make Starship, or Falcon Heavy ... and if you really want to go to the moon with fragile humans to use Starship. or Falcon Heavy. Don't the waste time and money on the over expensive, way late, fire-dump, repurposed old technology SLS.

SLS gets us to the moon, but is a dead end technologicaly. Both Falcon and Starship moves us toward a future of cheaper access to space, which makes everything including lunar missions better.

At the moment, Starship is still vapourware. Elon has made numerous predictions which all failed to materialise:
Sep 2017: Elon forecasts 2 cargo flights to Mars in 2022 and the first human carrying flight to Mars in 2024
Dec 2019: Elon forecasts first Starship orbital flight in 2020 and a tourist flight around the moon with up to eight passengers in 2023
Dec 2020: Elon forecasts first Starship orbital flight in 2021 and a flight to Mars with latest date to land on Mars by 2026 and and if luck 2 years earlier.
Nov 2021: Elon forecasts a dozen launches in 2022
Aug 2022: Elon forecasts a orbital flight within weeks or up to 12 months later (this is the only one still possible...)
And they started on Starship around 2005.

If SLS had this track record it would have been cancelled.

On the other hand, the Webb telescope was many years late and far over budget, but the results are absolutely spectacular and exceed my wildest expectations. So NASA is not completely incompetent.

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. And it's not cancelled.

Also, Starship was only a concept in 2005. Also, SLS was a concept before it was a $2.5B/year budget item. Also, Musk is (not sure the right word here).

Avatar2go wrote:

bobinthecar wrote:

IF SLS can send payloads on direct trajectories in a single launch why is it that they need a modified version of Starship to land and return astronauts from the moon? How is Starship getting out of orbit? Do a little research. You will see that the lander is launched in to lunar orbit and only then is refueled for the trip down to the surface and back.

Falcon heavy is already at 97million a launch and it has a TLI capacity of about 22 tons.

So again this is based on misunderstanding. SLS Block 1 is designed to send Orion to the moon. To do that requires the ICPS, which is a payload for the core stage, just like Orion. The combined weight of those is around 60 tons. So no way does Falcon Heavy have that lift capability.

For Orion/ICPS, the core stage has a margin of about 10 tons, that is not used. But will be used on later flights. SLS Block 1B and Block 2, can lift much more, about 100 to 130 tons to LEO. This is because they use EUS, which is a true second stage, unlike ICPS, which is a kick stage.

Thus with Block 1/ICPS, it's not possible to send the lander on the same flight. As noted this is because Orion is a large and heavy vehicle. For Block 2, it was possible, but NASA decided to use 2 launches, which gives them a much larger lander.

The original HLS solicitation required the lander to be launcher agnostic, as Starliner and Cygnus also are. However as with the other commercial programs, NASA waived that requirement for SpaceX, because there is no hope of compability with their hardware.

The notion that Starship can leave orbit without refueling is incorrect. It will need refueling in Earth orbit to get to the moon, and then will be out of fuel after it ascends from the lunar surface. This means to be re-used, it will need refueling in lunar orbit as well. NASA has deferred that capability for HLS, because there was no hope of lunar refueling being ready in the HLS mission timeframe. It will be pushed to the Option B follow-on contract for the sustainable lander.

Lastly for Falcon Heavy, the cost of launching the Gateway modules to lunar NRHO (same destination as Orion with SLS), is $330M. Falcon Heavy is able to break $100M with very small payloads, as a minimum case. But nothing on the scale of lunar missions.

The goal is not to spend about $100B to get new footprints on the moon. The goal is long term cheaper access to space in quantity. SLS does not move us toward that goal. Resuable rockets like Starship do.

You can write about how Starship with it's lower ISP fuel has trouble with deep space missions and I'll agree. But it's on the path toward cheaper access to space, and SLS is just a super-expensive way to get more footprints on the moon.

I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship. I'd be really curious on your view of this point.

("footprints on the moon" is an over-simplification done to make the above text much smaller. I hope you know what I mean, but if not I can tediously explain.)

kitplane01 wrote:

The goal is not to spend about $100B to get new footprints on the moon. The goal is long term cheaper access to space in quantity. SLS does not move us toward that goal. Resuable rockets like Starship do.

You can write about how Starship with it's lower ISP fuel has trouble with deep space missions and I'll agree. But it's on the path toward cheaper access to space, and SLS is just a super-expensive way to get more footprints on the moon.

I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship. I'd be really curious on your view of this point.

("footprints on the moon" is an over-simplification done to make the above text much smaller. I hope you know what I mean, but if not I can tediously explain.)

As explained earlier, reusability is a trade, not a miracle. It comes with its own costs, and it's not clear yet what the balance will be between reusability and expendability. Notably all the reusable rockets offer an expendable version. That's not without reason.

Also as explained earlier, Artemis is far more than just boots on the moon, so to claim we are spending $100B on that is just not accurate, or truthful.

As NASA has explained endlessly, the purpose of Artemis is to develop the infrastructure for human habitation far from Earth. We did this in earth orbit with ISS first, to learn. Next will be lunar orbit with Gateway, initially part-time, to learn. Following will be the lunar surface, initially part-time, to learn. And if we learn enough, and develop enough, then maybe 20 years from now, we will have a shot at humans in Mars orbit, and then on Mars surface.

Whether you are willing to accept it or not, SLS has a role to play in all of that. It was designed specifically for those missions, and will be used for those missions. Starship also will have a role to play, but it won't be the same role. And it's role is not as certain as SLS, because it's still a prototype, its costs and performance are not yet quantified.

All the claims that we don't need SLS because we will have Starship, are not only factually inaccurate, but are examples of magical thinking. Starship is not some panacea that will solve all spaceflight. Like SLS, Starship is a stepping stone, that likely will transition to transport vehicles that are nuclear powered. By that time, we will have moved on from both SLS and Starship.

In the meantime, both SLS, Starship, and many other platforms, are going to help us get there. But it will be an evolution, and a process, and a great deal of it is very highly uncertain. That's what makes it great. Success is not assured, but we need all the tools we can muster to succeed.

That's why, quite frankly, all the argument about SLS vs Starship is useless and pointless, if not downright stupid. It only distracts and subtracts from the benefits we have the opportunity to achieve. It serves some ridiculous notion about superiority of one over the other, but neither was designed for that purpose, or with that in mind. It's a construct of the fan bases, and not a particularly healthy one.

Avatar2go wrote:

kitplane01 wrote:

The goal is not to spend about $100B to get new footprints on the moon. The goal is long term cheaper access to space in quantity. SLS does not move us toward that goal. Resuable rockets like Starship do.

You can write about how Starship with it's lower ISP fuel has trouble with deep space missions and I'll agree. But it's on the path toward cheaper access to space, and SLS is just a super-expensive way to get more footprints on the moon.

I bet your vision of the 20 years from now future includes nothing like the SLS, and a lot like Starship. I'd be really curious on your view of this point.

("footprints on the moon" is an over-simplification done to make the above text much smaller. I hope you know what I mean, but if not I can tediously explain.)

As explained earlier, reusability is a trade, not a miracle. It comes with its own costs, and it's not clear yet what the balance will be between reusability and expendability. Notably all the reusable rockets offer an expendable version. That's not without reason.

Also as explained earlier, Artemis is far more than just boots on the moon, so to claim we are spending $100B on that is just not accurate, or truthful.

As NASA has explained endlessly, the purpose of Artemis is to develop the infrastructure for human habitation far from Earth. We did this in earth orbit with ISS first, to learn. Next will be lunar orbit with Gateway, initially part-time, to learn. Following will be the lunar surface, initially part-time, to learn. And if we learn enough, and develop enough, then maybe 20 years from now, we will have a shot at humans in Mars orbit, and then on Mars surface.

Whether you are willing to accept it or not, SLS has a role to play in all of that. It was designed specifically for those missions, and will be used for those missions. Starship also will have a role to play, but it won't be the same role. And it's role is not as certain as SLS, because it's still a prototype, its costs and performance are not yet quantified.

All the claims that we don't need SLS because we will have Starship, are not only factually inaccurate, but are examples of magical thinking. Starship is not some panacea that will solve all spaceflight. Like SLS, Starship is a stepping stone, that likely will transition to transport vehicles that are nuclear powered. By that time, we will have moved on from both SLS and Starship.

In the meantime, both SLS, Starship, and many other platforms, are going to help us get there. But it will be an evolution, and a process, and a great deal of it is very highly uncertain. That's what makes it great. Success is not assured, but we need all the tools we can muster to succeed.

That's why, quite frankly, all the argument about SLS vs Starship is useless and pointless, if not downright stupid. It only distracts and subtracts from the benefits we have the opportunity to achieve. It serves some ridiculous notion about superiority of one over the other, but neither was designed for that purpose, or with that in mind. It's a construct of the fan bases, and not a particularly healthy one.

Let me put the words from your post in the right order. ( I added the word economics.)


"Quite frankly, all the argument about SLS vs Starship is useless and pointless, if not downright stupid. As explained, we have different purposes. The correct purpose is to make space access cheap and reliable. This requires reusable rockets, and thinking it can be done with throw-away rockets is a rediculous notion if not magical thinking. Resuability is a trade, not a miracle. It comes with its own costs, but it's clear what the balance will be between reusability and expendability: we are very sure that use-once-and-throw-away rockets are not the way to cheap access to space.

Whether you are willing to accept it or not, economics matter. Ignoring economics is a construct of the fan bases, and not a particularly healthy one."

I wish you had answered the question about if you really see SLS as the way forward on something like a long term time span (maybe 20 years). Because $2B per launch (if you believe that cost) is not the answer to a sustained space program.

Just so we're super double ultra clear ... The right mission is cheap reliable access to space. If you really want to get back to the moon, start by developing cheap space travel. SLS is old tech that will get us to the moon but will not get us economical space travel. Resuable rockets are the future, and SLS is a super expensive tech dead end.

JetBuddy wrote:

Would an expendable Starship / Booster combo be able to deliver the same C3 as SLS?

Sorry I didn't see this earlier, in the flurry of responses, today. The answer is no, because the design of Starship and Super Heavy are such that they are mass constrained beyond the point that they could leave earth orbit, even if expended. They should be able to reach high orbits, such as GEO.

Super Heavy needs to stage earlier than is ideal, in order to survive the trip back to the surface, with enough propellant to land. So for the expendable version, the main benefit is that it can stage later in the flight, which adds characteristic energy. But it's still lifting a heavy Starship. Depending on the mission, a lighter version of Starship might be provided to get more benefit from expendability.

One of the problems SpaceX faces with Starship, is that all the components are currently overweight. That's not unusual in rocket development, and hopefully they will get that down, without losing much in the way of payload.

This becomes especially important for HLS, as once refueled in Earth orbit, it must do a TLI, then enter lunar NRHO, then descend to LLO, then descend to the surface, then ascend to LLO, then to NRHO. All with no new source of fuel, and with a sizable margin for contingencies, since it carries crew. It's a big ask which they currently could not do.

NASA is working on contingency plans where Orion could meet with HLS in LLO in an emergency, but that would likely cause Orion to be expended, as it could not return to Earth afterwards. Astronauts would hang out in the Gateway until rescue. Orion has a contingency to carry 6 crew in that case.

kitplane01 wrote:

Let me put the words from your post in the right order. ( I added the word economics.)


"Quite frankly, all the argument about SLS vs Starship is useless and pointless, if not downright stupid. As explained, we have different purposes. The correct purpose is to make space access cheap and reliable. This requires reusable rockets, and thinking it can be done with throw-away rockets is a rediculous notion if not magical thinking. Resuability is a trade, not a miracle. It comes with its own costs, but it's clear what the balance will be between reusability and expendability: we are very sure that use-once-and-throw-away rockets are not the way to cheap access to space.

Whether you are willing to accept it or not, economics matter. Ignoring economics is a construct of the fan bases, and not a particularly healthy one."

I wish you had answered the question about if you really see SLS as the way forward on something like a long term time span (maybe 20 years). Because $2B per launch (if you believe that cost) is not the answer to a sustained space program.

Just so we're super double ultra clear ... The right mission is cheap reliable access to space. If you really want to get back to the moon, start by developing cheap space travel. SLS is old tech that will get us to the moon but will not get us economical space travel. Resuable rockets are the future, and SLS is a super expensive tech dead end.

Please do not alter or twist my thoughts and words to suit your purpose. That is an extremely lame form of argument, that is responsible for much of the misinformation put forward on this subject. You should be able to formulate and express your own independent thoughts & points, without co-opting mine. If you can't do that, we are done here.

Your point about the expense & economics of space travel is well taken, however nothing about any of this is going to be inexpensive. The cost of an SLS launch is not that significant in the grand scheme of things, relative to other program costs. As I explained, that cost will come down over time.

As I also explained, in great detail, the cost of Starship launch for deep space missions, is not assured to be much less, due to the logistics of the trades. For LEO missions, Starship has a significant cost advantage. But SLS is not intended for LEO missions.

I hope and expect that the cost of both vehicles will support their different purposes. That is all that needs to happen, for them both to be viable. As things stand now, NASA has established that they are viable, or will be.

You of course are free to think otherwise, but that doesn't change the facts, or the progression of the Artemis program.

With regard to the SLS "old tech" claims, that has been asked and answered, and shown to be a misrepresentation, so no need to address it again.

At the end of the day, this whole SpaceX great, NASA terrible is ill informed, without NASA and the COTS program SpaceX would likely not be around. Musk has said so himself.
It is also about a weird, narrow minded ideology which is historically risible, especially in terms of space flight.
Those awful government run people at ESA not only successfully launched JWST they did it so precisely it has added 5-10 years to its life by saving propellant for station keeping.
Some may remember how that vehicle went on its first launch attempt, how many had a good laugh and general air of smugness, in the US especially. Not so smug when it went on to dominate the commercial launch vehicle market for best part of the next two decades, plus other less well known but significant launches for science payloads.
How terrible of them to undermine shibboleths based on ideology, not experience and expertise, both of which takes a lot of money and time to build up.

Fact is the first human flight on any Starship variant will be the HLS version.
Launched from Earth, the more standard orbital Starship has no launch escape system, NASA learned the hard way with the Shuttle of the folly of that.
Far more likely it will be, when launched from Earth, either hauling cargo and many will also have to be the tanker version, so far unproven as as concept in orbit at least on that scale.

To claim that SLS is ‘vapourware’ in the same way that Starship also seems perverse.
A completed ready to launch vehicle is ready to go once those kinks in the process are ironed out.
And it’s thought or just assumed that a 33 engined launch vehicle like Starship, still not ready for a suborbital, ditching in the water test flight, won’t have any?
Even at this early stage, it already is, if you are actually following what is going on at Starbase, which I suspect the ultra SpaceX fans are not, ironically enough.

All launch vehicles have scrubs, especially on the first attempt. Again any beyond the tabloid style reporting surface would tell you that.
SpaceX will get there most likely, as before though it will be with and not in some kind of race with NASA.
To go beyond LEO they need each other.

I personally find these comparisons with Starship to be way off the mark.

The design philosophies are completely different.
SLS was built from the ground up to be a man-rated system for moon missions. It has no other purposes and needs to work from the first launch.

Starship is an incremental project that is intended to culminate into a man-rated multi-purpose space vehicle but that will take a lot of time and is meant to slowly build towards its ultimate goals through multiple unmanned launches, mostly supporting SpaceX's own Starlink system.
For all the Musk fanboyism, the Starship project is so ambitious that it would be presumptuous to assume its eventual fate based on SpaceX's previous success with F9 alone. The engineering realities of a fully reusable vehicle of this size are extremely sobering, and I think even SpaceX knows this.
It is obvious to me that Starship's underlying urgency with SpaceX lies only in their reliance on it to launch enough hardware into orbit to make Starlink a viable venture. For all their progress since they began assembling stainless steel grain silos in the middle of nowhere and strapped rocket motors on them, they are still a long way away from their goal.
We've been hearing promises of a launch for a while now. They first used the FAA's environmental review as an excuse for the delay, but it is now clear that they were nowhere near ready and, for all the continued promises, who knows how close to it they really are now. The latest rumors is that they are now looking at making the upper stage (Starship) expendable initially, hinting at the fact that they are encountering quite a lot of difficulties with the reentry systems. That and other hints like having issues even keeping the tiles from falling off at every single test firing gives an idea of how far they still are from a rapidly reusable orbital vehicle.

Even if/when they manage to finally make it as usable and re-usable as they aim, it will take a long string of uneventful launches and recoveries before they allow any humans on there. There is also the fact that they need to design a habitable and survivable cabin for it, which is no small endeavor. Despite the Musk-generated hype, we are many years away from seeing anyone climb into one of these things.
Whereas we know how much money SLS is costing, being a publicly funded venture, we have no idea how much money SpaceX is shoving into the Starship program. Incremental design at this level cannot be cheap and it will only happen because they intend to finance it through Starlink. In fact, if you ask me, Starship first and foremost exists for Starlink.
Much as is the case for the Tesla truck/semi/roadster, usable FSD, all his AI/robot nonsense, neuralink, tunnels, solar roofs etc., Elon is very good at making outlandish promises without filing in the obvious technical blanks but, because of his previous successes, people take his word for gospel.
He is a marketing genius well before an engineering one...

I have no conviction whatsoever that NASA would have been better off, in terms of costs or schedule, waiting for SpaceX or even Blue Origin to make a moon rocket for them.
Making a man-rated translunar rocket for the kind of missions NASA aims to accomplish and that needs to be fully operational from launch #1 is going to be a long and costly endeavor any way you go about it. I am sure it could have been more efficient and quick without contractors that have obviously become a bit too comfortable suckling at the government's teat, but not convinced that it wasn't the way to proceed.

Vintage wrote:

AngMoh wrote:

At the moment, Starship is still vapourware.

At the moment SLS is still vaporware.

AngMoh wrote:

Elon has made numerous predictions which all failed to materialise

The arguments against SLS aren't in any way boosterism for Eldon Musk, and aren't about Space X.

For me, it is a question of using last century's technology vs building the future Space program.
SLS is a dead end.

Neither SLS nor Starship are vaporware. SLS is a small technical issue away from being operational. Starship is at the early prototype stage and a lot of the design and infrastructure has been done.
That said, SLS is much, much further along towards launching humans into space than Starship is.

SLS may be a technical dead end (only if reusability at these kinds of scale and energy ever become doable, which is far from a thing yet), but at the moment, it is the only way to send humans to the moon.
In 20 or 30 years, I'm sure there will be better ways to do it thanks to the increasing commercialization of space and the advent of leaner engineering companies funding new technologies to take advantage of these new markets. Until then, if you want Americans on the moon, SLS is the way to go.

Another differentiator between SLS and Starship, which makes them not directly comparable, as GDB reminded us above:

Starship will not be human rated within the Earth environment. It will be human rated for the space, lunar, and likely Mars environment.

For SpaceX this was a concious design decision, because as Francoflier noted above, the economic purpose of Starship is delivering cargo to LEO. But it also has non-economic potential in terms of Musk's dream of reaching Mars. So it makes some trades, to have the potential for success in both missions.

SpaceX also has the option of using Crew Dragon as a taxi for Starship crew, to work around the design limitation for the Earth environment.

SLS is human rated for the Earth and deep space environments. Orion cannot be human rated for the Moon or Mars because it doesn't land. However for landers or habitats that are large enough to justify SLS, they could adopt that role.

All of this taken together, emphasizes the need for all the platforms to work together. No single platform addresses all needs. NASA and SpaceX recognize this, they need each other. That is the simple truth. Further NASA has diversified all the commercial programs, so as not to be totally reliant on any one provider. Always there are two.

Excellent discussion.

When Artemis was proposed by NASA in 2012 spaceX had no track record. Today SpaceX clearly has a big lead over the competition.

The one problem I have with Artemis is that the Orion spacecraft and SpaceX Moonship lander are both going to the moon in parallel and have to launch separately. It is more complex than the Apollo mission with refueling in space required.

I scratch my head wondering why the moon lander doesn't launch with the astronauts. Such as follows:

Stage 1: Gets to 80km with solid rocket boosters.
Stage 2: Four Shuttle RS-25 rockets gets to Earth orbit.
Stage 3: Single RS-25 rocket sends to moon.
Stage 4: Lands on moon, takes off and returns to Earth.
Stage 5: Re-entry capsule with heat shields and parachutes.

KISS. Keep It Simple Stupid. Basically the Apollo service module, the descent and ascent moon lander stages get combined into one ship. Not that hard.

Based on the performance goals of SpaceX Starship I assume a fully fueled Moonship will be able to go from Earth orbit, land on the moon and return back to Earth orbit. Basically NASA is funding spaceX to have a monopoly in the future. Future moonships will go back and forth to the moon hundreds of times. No heavy heat shields or strong landing legs are required for earth landings.

Fast forward 30 years and say we have a large space station in Earth orbit that also acts as a fuel depot. Starship with heat shields can carry a dozen passengers from Earth along with 100t of fuel to offload to the space station. Moonship can then fly back and forth from the space station and moon very easily. Likewise the Mars flights can refuel from the space station in one hit. The fuel depot part of the space station I am certain they will simply launch starships into orbit without headshields or landing legs. They will then remove the raptor engines in space and bring them back to Earth.

Starship being fully reusable is 99% of the difficulty in my opinion. Hats off to SpaceX. I do not like to use the word fanboy as it usually means a person has an uneducated bias. SLS disappoints me and is setting the bar very low being fully disposable. It might not even succeed. I agree with the comments that it is a technology dead end.

In fairness RJMAZ, Artemis really only became a defined program fairly recently, in the past 5 years.
It wasn't only political interference, a tug of war over funding COTS and SLS that caused delays, a lack of a defined mission did not help SLS.

Avatar2go wrote:

Please do not alter or twist my thoughts and words to suit your purpose. That is an extremely lame form of argument, that is responsible for much of the misinformation put forward on this subject. You should be able to formulate and express your own independent thoughts & points, without co-opting mine. If you can't do that, we are done here.

You wrote using the words pointless, useless, magic thinking, stupid, not heathy, etc.
I just wanted to use those words too.

We can be done here.

RJMAZ wrote:

Excellent discussion.

When Artemis was proposed by NASA in 2012 spaceX had no track record. Today SpaceX clearly has a big lead over the competition.

The one problem I have with Artemis is that the Orion spacecraft and SpaceX Moonship lander are both going to the moon in parallel and have to launch separately. It is more complex than the Apollo mission with refueling in space required.

I scratch my head wondering why the moon lander doesn't launch with the astronauts. Such as follows:

Stage 1: Gets to 80km with solid rocket boosters.
Stage 2: Four Shuttle RS-25 rockets gets to Earth orbit.
Stage 3: Single RS-25 rocket sends to moon.
Stage 4: Lands on moon, takes off and returns to Earth.
Stage 5: Re-entry capsule with heat shields and parachutes.

KISS. Keep It Simple Stupid. Basically the Apollo service module, the descent and ascent moon lander stages get combined into one ship. Not that hard.

Based on the performance goals of SpaceX Starship I assume a fully fueled Moonship will be able to go from Earth orbit, land on the moon and return back to Earth orbit. Basically NASA is funding spaceX to have a monopoly in the future. Future moonships will go back and forth to the moon hundreds of times. No heavy heat shields or strong landing legs are required for earth landings.

Fast forward 30 years and say we have a large space station in Earth orbit that also acts as a fuel depot. Starship with heat shields can carry a dozen passengers from Earth along with 100t of fuel to offload to the space station. Moonship can then fly back and forth from the space station and moon very easily. Likewise the Mars flights can refuel from the space station in one hit. The fuel depot part of the space station I am certain they will simply launch starships into orbit without headshields or landing legs. They will then remove the raptor engines in space and bring them back to Earth.

Starship being fully reusable is 99% of the difficulty in my opinion. Hats off to SpaceX. I do not like to use the word fanboy as it usually means a person has an uneducated bias. SLS disappoints me and is setting the bar very low being fully disposable. It might not even succeed. I agree with the comments that it is a technology dead end.

A couple things here that need clarification:

1. The reason the capsule, service module, descent and ascent stages are not combined into a single stack, is that it severely limits the mass of the lander, and that can be delivered to the moon. That was the case with Apollo, and NASA is looking to improve on the lander mass with Artemis.

2. The HLS flight structure is actually very inefficient, as it hauls a large mass around throughout it's mission. The inefficiency is offset by using many secondary launches to provide additional propellant. As noted earlier, the thing that makes that viable is the projected very low launch cost of Starship, but that is not yet proven. NASA is committed to HLS so will pursue it regardless of the actual cost.

3. Starship cannot be certified for human-rated operations in the Earth environment, because it relies on active systems that have no abort or contingency redundancy. As I mentioned that is a non-starter for NASA. But as explained, commercial crew is a workaround that is human-rated by NASA.

SpaceX has mentioned forming their own astronaut corp, which would operate outside the NASA requirements. That would require those people to sign an FAA waiver that they understand the risks, and also would somewhat limit SpaceX interaction with NASA. Recently SpaceX has backed off on that somewhat, I suspect because they recognize that full cooperation and collaboration with NASA is the preferred path.

HLS was won for the initial missions by SpaceX in no small part due to the crapness of the other contenders.

From the NASA Artemis media conference today:

1. The umbilical hydrogen seal was found to be damaged, possibly from the replacement process that was done after last WDR. The pressure surge may have initiated or exacerbated the leak, but was not the root cause.

2. NASA apologized to the valve operator for changing procedures before the launch attempt. Entire agency had their finger on the button, agency is responsible, not the operator. Just culture in action.

3. The seal will be replaced by end of day today. They have decided to alter their procedures to moderate pressure and temperature swings in the system, and will do a full tanking test to confirm on Sept 17th, as well as give teams a chance to practice.

4. NASA has applied for a waiver with range, for launch dates on Sept 23rd and 27th. Range requested an extended data set to justify the waiver. NASA has supplied the data and it's now under review. Range has some time yet to make a decision. NASA assessment is that it could go either way.

5. If range declines the waiver, Artemis roll back to the VAB for FTS recertification, and NASA will make a new assessment for launch date.

5. Questions were asked about SRB life, tanking life, vehicle life, rollback life. NASA said none are an immediate concern, but they continuously evaluate based on data collected.

GDB wrote:

HLS was won for the initial missions by SpaceX in no small part due to the crapness of the other contenders.

In fairness, also because it was the only possible choice under the funding provided by Congress. That has now changed, to allow multiple vendors.

Also in fairness, the other vendors tried to comply with the example system NASA put forth in the HLS solicitation. When SpaceX came in with Starship, it was viewed as an intriguing option, but deviated substantially from the example, with the highest risks. NASA acknowledged this in the down-select. But cost ultimately & necessarily took precedent over risk.

However there is no question that SpaceX has disrupted & changed the lander expectations. It will be interesting to see how the other vendors will respond, and how their lander designs will adapt to the new challenge from SpaceX HLS. The value of commercial competition.

Duplicate sorry

Francoflier wrote:

I personally find these comparisons with Starship to be way off the mark.
...
SLS may be a technical dead end (only if reusability at these kinds of scale and energy ever become doable, which is far from a thing yet), but at the moment, it is the only way to send humans to the moon.
In 20 or 30 years, I'm sure there will be better ways to do it thanks to the increasing commercialization of space and the advent of leaner engineering companies funding new technologies to take advantage of these new markets. Until then, if you want Americans on the moon, SLS is the way to go.

Let me ask you ....

What is your reasonably achievable hope for launch systems 20 years from now? Do you really picture SLS-like rockets?

GDB wrote:

In fairness RJMAZ, Artemis really only became a defined program fairly recently, in the past 5 years.
It wasn't only political interference, a tug of war over funding COTS and SLS that caused delays, a lack of a defined mission did not help SLS.

But isn't this how it always is these recent decades? This doesn't seem a bug in this program so much as a deep design flaw in the system that will re-occur.

Apollo really was the best.

Mods can we keep this thread on topic, this thread is for launch updates, if you want to debate whether SLS vs Starship is the future create a new thread.

I've been enjoying the updates here from Avatar2go and now I have to scroll through off topic messages.

nycbjr wrote:

Mods can we keep this thread on topic, this thread is for launch updates, if you want to debate whether SLS vs Starship is the future create a new thread.

I've been enjoying the updates here from Avatar2go and now I have to scroll through off topic messages.

Concur. This debate is old and tired - it’s been done before. SLS has bipartisan support in Congress and from White House, it’s not getting canceled.

Work to correct LH2 feed and bleed lines + seals seems complete. They will now move to tanking and systems tests to make sure the leak has been resolved.

https://blogs.nasa.gov/artemis/2022/09/ ... king-test/

An update on Artemis: teams have requested a shift of the cryogenic tests from Sept. 17th to Sept. 21st, to allow for weather, system checks, and crew rest. They now will do a series of tests at ambient conditions before the cryo tests.

This also shifts the earliest launch date to Sept 27th, with a backup date of Oct 2nd. That is contingent on range approval of the FTS extension, which is still being evaluated.

If range declines the request, Artemis will roll back to the VAB after tests on the 21st. That may allow a launch opportunity at the end of LP27. Or the decision may be made to defer until LP28, in the middle of November.

The Oct 2nd launch may be iffy due to conflicts with Crew-5 launch to the ISS. Discussions are underway with SpaceX on deconfliction.

https://blogs.nasa.gov/artemis/

NASA will have live coverage of the Artemis tanking demonstration on Wednesday Sept 21.

There will also be a media conference on Monday Sept 19th at 11:30 am ET.

https://www.nasa.gov/press-release/nasa ... media-call

NASA has released the RFP for the Sustainable Lunar Development contract, which covers the lunar landing and base systems that will follow HLS. The repeatable & sustainable mission requirements are:

First human reference mission: 6 day lunar stay, lander must deliver 2 astronauts and 1 ton of cargo, support 5 EVA's, then return astronauts and half ton of cargo to Lunar Gateway.

Second human reference mission: 33 day lunar stay, lander must deliver 4 astronauts and 2 tons cargo, transfer crew to lunar surface habitat and back, then return astronauts and 1 ton cargo to Lunar Gateway.

Autonomous cargo reference mission: deliver 12 tons of cargo directly to the lunar surface, without assistance from Lunar Gateway.

The human lander specifications are:
1. Full autonomous and full manual capabilities
2. Full abort capability for any stage of the mission
3. Continuous HD video, including surface camera
4. Loss of crew risk less than 1:75
5. Loss of mission risk (abort) less than 1:10

This contract is open to all vendors except SpaceX, for which a separate add-on contract for HLS will be awarded. Thus it will result in two landing systems, one based on HLS. Those two systems will then complete for NASA lunar operational contracts. This is similar to the structure of commercial cargo and crew for the ISS.

For the lunar EVA spacesuits, NASA has already selected Axiom Space and Collins Aerospace as the two commercial vendors.

Here is a good summary of the award system, including history and current status of the Artemis and HLS programs:

https://www.spacescout.info/2022/09/sec ... ander-rfp/

A key part from that article.

In a report dated November 15, 2021, from NASA OIG, titled “NASA’s Management of the Artemis Missions”, the Inspector General declared that the Starship HLS schedule is “unrealistic and not supported by recent schedule risk analysis.”

My take is that NASA is requesting a smaller backup landing solution.

I always had doubts if Moonship (Starship HLS) would be ready by the original Artemis timeline. Though the timeline is slipping due to the other contractors giving SpaceX some extra time.

The Artemis programs seems to be mismanaged. The Industry is moving fast and NASA has too many options to choose from. From the very start NASA should have planned for a small lander to go with the astronauts just like Apollo.

SLS is very similar in size to the Saturn V. One has slightly more thrust while other is slightly heavier. Over 60 years of technology improvements yet the SLS can't carry a small moon lander like the old Saturn V rocket.

Did NASA originally allocate some payload weight to carry a moon lander on Artemis SLS?

I do remember reading something along these lines. That would explains the big SLS rocket and the lander options simply ended up exceeding the maximum payload weight of SLS.

Did the Orion and service module become overweight so the lander had to be removed?

Instead of NASA scaling up SLS with say an extra booster segment and a fifth RS-25 on the core stage they have silently removed the moon lander to launch separately. I am certain the lander was originally meant to go with SLS and I was shocked when I read the lander proposals where they now had to make their own way to the moon.

RJMAZ wrote:

SLS is very similar in size to the Saturn V. One has slightly more thrust while other is slightly heavier. Over 60 years of technology improvements yet the SLS can't carry a small moon lander like the old Saturn V rocket.

Did NASA originally allocate some payload weight to carry a moon lander on Artemis SLS?

Some background: SLS has shifted roles a few times between administrations. The core stage has remained the same, but the Exploration Upper Stage (EUS) was put on hold and nearly cancelled, then later revived, and is now in development.

Thus SLS Block 1 has the Interim Cryogenic Propulsion Stage (ICPS), which is borrowed from the ULA Delta rocket and was immediately available, but has limited capability. It's really a kick stage for Orion and the service module, rather than a true upper stage. It doesn't fire until after the combined stack is put in orbit by the core stage. Block 1 can put the entire stack into TLI, but there is no margin remaining for a lander.

SLS Block 1B will have the EUS, which greatly expands the lift capability. It has a margin of 10 tons that can be utilized for other co-manifested payloads, such as Gateway modules or cargo. However due to the extended stay requirement, this was considered too limiting for the lander design. So it was decided to use a second launch for the lander, which allows for much greater capability.

SLS Block 2 will have the new BOLE boosters, which are greatly improved, and will increase the lift yet again. This could have 15 to 20 tons co-manifested payload, which might be capable of including a small lander. But my guess is they will stick with the separate lander launch, as it provides for more lander options.

Did the Orion and service module become overweight so the lander had to be removed?

Orion as originally designed, was a much heavier and more capable vehicle. In the Constellation and Ares era, it had to be slimmed down considerably due to performance issues on those rockets. It is still larger and heavier than the Apollo command module, as is it's service module, due to the much longer durations of Artemis missions. It must support the crew for 21 days, with an additional 7 days of contingency life support for the crew suits. It also must have a docked life of 18 months in space.

It's a shame that the program development wasn't such that SLS Block 2 was available for the original Orion, it could have been much better. But such are the vagaries of Presidential and Congressional support. Biden has been the first President to not alter the program.

Instead of NASA scaling up SLS with say an extra booster segment and a fifth RS-25 on the core stage they have silently removed the moon lander to launch separately. I am certain the lander was originally meant to go with SLS and I was shocked when I read the lander proposals where they now had to make their own way to the moon.

The existing boosters do have an extra segment. The new BOLE boosters also have a lot more propellant, due to the lighter composite casing. The 5th RS-25 was considered in the trade studies, and the conclusion was that it was more effective & efficient to invest in the EUS, which would provide more characteristic energy on orbit.

As mentioned, I don't think there was ever an intention to launch Orion and lander together. That worked for Apollo, but not for Artemis.

Another vagary of the program history, was that Orion was originally supposed to be capable of ISS missions, as a NASA alternative to commercial crew. This meant that the core stage could not be too powerful, as it would be used alone with Orion for ISS.

As the SpaceScout article makes clear, the program has been rife with alternating political decisions that didn't result in a clean path forward. But it is what it is now.

You mentioned the HLS, that was a consequence of Pence accelerating the program from 2028 to 2024, while Congress simulataneously funded the lander at 20%. Those two things together forced the selection of SpaceX, which had the lowest cost but highest risk. Congress and NASA are correcting that now, two landers are funded.

My expectation is that HLS will slip back into the original 2026 to 2028 timeframe, and that shouldn't really surprise anyone, or be considered a failure. The acceleration was another political decision, which had no roots in technical reality.

From the NASA Artemis media conference today for tanking demonstration test on Wednesday Sept 21.

1. Includes loading LOX and LH2 to both core stage and ICPS, to test all umbilical seals for leaks.

2. New kinder and gentler loading procedure to lessen thermal shock and better condition lines before entering fast-fill. Requires an additional 30 minutes in countdown.

3. Conduct the engine conditioning kickstart test, as well as pre-pressurization test to ensure adequate cryogen flows through the engines.

4. De-tank the vehicle and begin preparing for launch attempt on Sept 27th, for 39 day mission.

5. Don't have a root cause for the indentation of the leaky seal, but have addressed the entire fault tree, all possible causes. (Verification photographs show seal was ok at installation).

6. The accidental valve activation has been addressed, software safeguards, changes and pauses added and practiced by the tanking team.

Still waiting for decision from Eastern Range on the waiver for the FTS system, don't expect decision until after the tanking test. If declined, vehicle rolls back to VAB for FTS recertification and future launch sometime in next two launch periods.

Word from NASA is that the indentation formed in the umbilical LH2 seal, may have been RTV silicone sealant contamination. At LH2 temperatures, it would freeze and solidify, then become brittle. Then possibly blown out by the 60 psi pressure surge.

RTV is used in the area around the umbilical, so might have gotten into the seal somehow. They are not certain, as whatever made the indentation, is long gone now.

Avatar2go wrote:

Word from NASA is that the indentation formed in the umbilical LH2 seal, may have been RTV silicone sealant contamination. At LH2 temperatures, it would freeze and solidify, then become brittle. Then possibly blown out by the 60 psi pressure surge.

RTV is used in the area around the umbilical, so might have gotten into the seal somehow. They are not certain, as whatever made the indentation, is long gone now.

Good info!

Let's hope the tanking test goes well today.

JetBuddy wrote:

Avatar2go wrote:

Word from NASA is that the indentation formed in the umbilical LH2 seal, may have been RTV silicone sealant contamination. At LH2 temperatures, it would freeze and solidify, then become brittle. Then possibly blown out by the 60 psi pressure surge.

RTV is used in the area around the umbilical, so might have gotten into the seal somehow. They are not certain, as whatever made the indentation, is long gone now.

Good info!

Let's hope the tanking test goes well today.

You jinxed it...

The hydrogen tanking has been stopped as a leak similar to the one which scrubbed the last launch attempt has been detected.


They're warming up the LH2 line in hope that the thermal expansion will seal the leak then they will try again.

I forget what the structural cycle limit for propellant loading is, but they may be getting close.

Francoflier wrote:

You jinxed it...

The hydrogen tanking has been stopped as a leak similar to the one which scrubbed the last launch attempt has been detected.


They're warming up the LH2 line in hope that the thermal expansion will seal the leak then they will try again.

I forget what the structural cycle limit for propellant loading is, but they may be getting close.

That question has been asked regularly at the media briefings. They aren't yet close to the tanking limit.

This leak is interesting as there was no pressure surge this time. It starts right at the transition to fast fill. So wonder if the fluid flow pushes back on the umbilical plate and unseats the seal.

Francoflier wrote:

JetBuddy wrote:

Avatar2go wrote:

Word from NASA is that the indentation formed in the umbilical LH2 seal, may have been RTV silicone sealant contamination. At LH2 temperatures, it would freeze and solidify, then become brittle. Then possibly blown out by the 60 psi pressure surge.

RTV is used in the area around the umbilical, so might have gotten into the seal somehow. They are not certain, as whatever made the indentation, is long gone now.

Good info!

Let's hope the tanking test goes well today.

You jinxed it...

The hydrogen tanking has been stopped as a leak similar to the one which scrubbed the last launch attempt has been detected.


They're warming up the LH2 line in hope that the thermal expansion will seal the leak then they will try again.

I forget what the structural cycle limit for propellant loading is, but they may be getting close.

I know, I'm sorry!

Now they'll try something else, lowering the pressure on the hydrogen supply tank to below 5 psi?

If that piece of RTV wasn't a one off, you could be looking at a really long stand down. They can't just keep hoping nothing will leak if debris in the lines and joints is a chronic issue.

They are exploring the pressure vs leak relationship. That's actually really good from an engineering perspective, though not based on appearance.

Right now they are at the standard fast-fill pressure, with a very slight leak. But they have permission to push the pressure and force the leak, to get data.

Nomadd wrote:

If that piece of RTV wasn't a one off, you could be looking at a really long stand down. They can't just keep hoping nothing will leak if debris in the lines and joints is a chronic issue.

Agreed, but this time it resealed so was not likely contamination as before. The fact that they could heal it means it's differential thermal contraction and expansion, aggravated by pressure effects.

It also means the seal has little operational margin, so they may be looking at ways to increase that.

So a quick summary of the NASA Artemis tanking test today. It was all about thermal and pressure conditioning.

Yet they achieved all the test objectives, including a full tanking cycle through to replenishment, the kick-start test to initiate engine conditioning, and the pre-pressurization test to chill the engines into the start box. This took almost two hours longer than expected, as they paused to run additional tests on the seals, but they would have still marginally fallen into the launch window.

At the transitions of LH2 flows, from slow fill to fast fill, and at the start of engine bleed, there were again initial hydrogen leaks that required pauses. These are caused by shocks in temperature and pressure. However they were able to recondition and heal both seals in the 8" and 4" LH2 umbilicals, and continue operations.

Additionally as they got past the leaks, they saw that with increasing pressure, the seals improved and the ambient hydrogen readings went down, which is a validation of the pressure-actuated umbilical seals. That is something they had been looking for, but had not been able to observe in past tests.

The cryo engineers requested and got a temporary exemption to allow hydrogen concentrations around the umbilicals, as high as 10%. This was so they could try different pressures and explore the behavior of the seals. However this wasn't needed. After the initial excursions of 7% and 5%, which were above the launch criteria of 4%, there were no more excursions and the umbilical concentrations dropped for the remainder of the tests.

So they learned a lot today about the thermal response of the systems, and have a lot of data to review. They will continue to tweak things going forward. Now it will be up the Eastern Range and the weather, as far as whether they prepare for launch on the 27th, or roll back for FTS recertification.

NASA has an Artemis media conference scheduled for Friday at 12:30 pm ET, to discuss the tanking test and the launch opportunity on Sept 27th.

From the NASA Artemis media conference today:

1. They are happy with the tanking test and feel that it answered all their questions. Feel confident about their ability to manage leaks.

2. An engineer with experience from the shuttle program, explained that small hydrogen leaks are common, but are usually not reported unless they exceed the launch criteria. They are expected and the teams always have remediation pre-plans in place.

3. Range has granted the extension of the FTS certification life through the October 2 launch opportunity.

4. They are watching the tropical storm progress. The wind limit for Artemis 1 to stay at the pad is 74 knots sustained. To roll back, they need less than 40 knots.

5. Will have a meeting tonight based on the 5 pm forecast, and will continue to prepare for either rollback or launch, until the forecast is firmed up.

6. Would prefer to stay at the pad if at all possible, but will protect the asset first and foremost.

NASA has cancelled the Artemis launch for the 27th, due to weather being likely outside of the launch constraints. Also deferred the roll back decision until tomorrow.

Tropical Storm Ian is tracking to the north and west, also slowing. They will continue to observe the track overnight, before deciding.

They are now considering other launch opportunities in LP26, both before and after Oct 2nd. But will not decide until after the rollback decision is made.

NASA Artemis rollback decision meeting is scheduled around noon today, with an announcement around 1 pm ET.

Tropical Storm Ian has continued westward, with its Florida intercept track slowing and also drifting to the west, into the panhandle region. It's expected to develop into a major hurricane as it turns northward, then weaken somewhat as it approaches landfall on Florida.

The 50 knot wind probability for the Cape is holding around 10%. The vehicle can remain on the pad for winds up to 74 knots. But cannot roll back with winds over 40 knots.

How "waterproof" (for lack of a better term) is the insulation on the tank? Would sustained wind-driven rain, even if not up to tropical storm standards, cause issues?

TangoandCash wrote:

How "waterproof" (for lack of a better term) is the insulation on the tank? Would sustained wind-driven rain, even if not up to tropical storm standards, cause issues?

The SOFI foam is closed-cell, water resistant, so not really an issue to get wet.

NASA has deferred the roll back decision to either 11 pm tonight or 5 am tomorrow morning. They have moved the crawler under the rocket to save time, in the event they have to roll.

Ian continues to slow, which is making the forecast more uncertain, but also gives them more time.