Artemis 1 going to the Moon (launched Nov 16)

[Paul Colby]

Big rockets are more efficient than smaller ones.

Sorry, I didn't follow your comment. Doesn't mean it isn't spot on or incorrect somehow. My track record even while in aerospace wasn't what I consider stellar when it came to big picture stuff. As far as big rockets are more efficient, what are the metrics? Energy, time, money, mean fatalities per launch?

 

[.Scott]

Sorry, I didn't follow your comment. Doesn't mean it isn't spot on or incorrect somehow. My track record even while in aerospace wasn't what I consider stellar when it came to big picture stuff. As far as big rockets are more efficient, what are the metrics? Energy, time, money, mean fatalities per launch?

You're post was related to getting functional mass to orbit. Elon has described the reasoning behind the mammoth size of Starship as being the proportional size of its components as the scale goes up. Basically, there's a bunch of stuff that has to be on the rocket no matter what the rocket's size, so with a semi-fixed numerator, make the denominator big.

There's also been a lot of discussion about the practicalities of routinely assembling large components in orbit. Clearly it can be done (as with ISS), but in the Apollo era, the rendezvous maneuver alone was "new". Obviously, later space stations were assembled and refueled in orbit. Orbital refueling is planned for Starship. Blue Origin ULA has criticized the practicalities of the Starship refueling as related to the lunar landing mission (with obvious partiality to their own proposed solution).

So the "efficiency" is one of economy (your "money" option) and seems to be a combination of overall engineering efficiency and that numerator issue.

 

[Paul Colby]

Yeah, I get the trade in the era of Apollo given the state of the technology. In the present if one claims larger reusable rockets are better than more smaller reusable rockets, this is also quite a reasonable trade result. What I definitely don’t get a single massive one time use rocket.

 

[Filip Larsen]

https://arstechnica.com/science/202...attempt-to-launch-the-sls-rocket-on-saturday/:

During a news conference on Tuesday evening, NASA's program manager for the SLS rocket, John Honeycutt, said his engineering team believed the engine had actually cooled down from ambient temperature to near the required level but that it was not properly measured by a faulty temperature sensor.

If true that certainly makes it more likely the next launch attempt will at least move past this step (assuming here they will have enough time to replace the sensor over the next few days - even though it is NASA).

 

[gleem]

According to this article https://www.msn.com/en-us/news/tech...launch-its-moon-rocket/ar-AA11k1Mp?li=BBnbfcL , they are not replacing the sensor. (?) Examination of the engine does not show any problem so they assume the sensor is faulty. Replacing it would mean too much of a delay. The other engines did not reach the target temperature so they are starting the chill down sooner.

 

[.Scott]

Yeah, I get the trade in the era of Apollo given the state of the technology. In the present if one claims larger reusable rockets are better than more smaller reusable rockets, this is also quite a reasonable trade result. What I definitely don’t get a single massive one time use rocket.

The expectation is that Starship will be the best of all worlds. Big and 100% (both stages) reusable.
Rocket reusability has been criticized and then adopted by Europe and China.

 

[.Scott]

According to this article https://www.msn.com/en-us/news/tech...launch-its-moon-rocket/ar-AA11k1Mp?li=BBnbfcL , they are not replacing the sensor. (?) Examination of the engine does not show any problem so they assume the sensor is faulty. Replacing it would mean too much of a delay. The other engines did not reach the target temperature so they are starting the chill down sooner.

That's not the whole plan. According to that same article, they are going to give the engine more time to cool down and the sensor more time to detect the change. That wait could be enough. If it isn't, they are where they started and the article does not say where they would go from there.

 

[mfb]

ULA has criticized the practicalities of the Starship refueling as related to the lunar landing mission (with obvious partiality to their own proposed solution).

That was Blue Origin. ULA had nothing to do with that, they didn't propose any Moon lander either.

According to this article https://www.msn.com/en-us/news/tech...launch-its-moon-rocket/ar-AA11k1Mp?li=BBnbfcL , they are not replacing the sensor. (?)

If they can't replace the sensor on the pad then there is not much else they can do at the moment.
The past months have shown how problematic that approach is: Too many things that need fixing just to find the next things that also need to be fixed, leading to months of delays. No redundancy in the temperature measurement is another issue.

SpaceX can replace Raptor engines on the launch pad within a day. Not just a temperature sensor - the whole engine.

 

[PeroK]

If there's anything that will make us old cynics "feel like kids again" , it's Elon's plan to put a man on Mars. Most likely himself!

Best place for him, if you ask me!

 

[.Scott]

Best place for him, if you ask me!

Elon does seem to rub some people the wrong way. I can't say I understand how. I've heard him called "arrogant". Is that your impression?

 

[Paul Colby]

Elon does seem to rub some people the wrong way. I can't say I understand how. I've heard him called "arrogant". Is that your impression?

Elon turned rubbing people the wrong way into an art form. At the moment this make little practical difference.

Rocket reusability has been criticized and then adopted by Europe and China.

I have a difficult time taking such criticism seriously. If I reuse a rocket 10 times I recoup 9 of those launches minus the turnaround cost. The turnaround cost appear to be a small fraction of a launch given the observed turnaround time is so small (assuming fuel cost are small).

In the days of Apollo the business models were adopted from the economy of ICBMs. Reusability was a silly question in the 1960s.

 

[PeroK]

Elon does seem to rub some people the wrong way. I can't say I understand how. I've heard him called "arrogant". Is that your impression?

He seems to me like a mad megalomaniac, who believes we're living in a computer simulation from the future. It's frightening how much wealth and power are in the hands of one man, especially one with crackpot notions.

Others, no doubt, will see him as mankind's saviour.

 

[anorlunda]

Others, no doubt, will see him as mankind's saviour.

IMO, better than someone from the public sector.

 

[.Scott]

He seems to me like a mad megalomaniac, who believes we're living in a computer simulation from the future. It's frightening how much wealth and power are in the hands of one man, especially one with crackpot notions.

Others, no doubt, will see him as mankind's saviour.

I don't see him as either a maniac or a savior. I'm not sure what you mean by "crackpot notions". He often completely misses the mark (calling the Tesla driver assistant "autopilot" and the notion of parachuting from orbit come to mind), but he seems to be able to drive engineering to find very pragmatic solutions. Anyone in engineering for more than a decade or two has seen persistent management over-optimism. It's part of the process. I don't fault him for his aspirational goals - it's what keeps his engineering efforts energetic.

In the American democracy there are several ways of gaining influence. Pleasing the electorate is one. Gaining wealth is another. Both have elements of meritocracy and each drives different decisions.

Contemporary US statesmen are compelled to address basic constituent survival issues as a priority. If followed to its logical conclusion and wars are avoided, it would result in a very large population committed to survival. In contrast, shooting for the stars measures society by challenging accomplishments and is better at creating "purpose".

 

[Janus]

In the Apollo era they said* humans would land on Mars by 1985. Still waiting...

*World Book Encyclopedia circa 1967.

It might have been a reality, if Nixon hadn't cut funding to the NERVA project. By the end of 1968 they had already had developed an engine that met the requirements for such an endeavor. It was a lack of political will more than anything else.

 

[pinball1970]

Saturn V is still taller:

View attachment 313282

This was the comparison I was talking about, @Astranut

 

[fresh_42]

This was the comparison I was talking about, @Astranut

I was searching as far as NASA's fact sheet for the SLS but haven't found a comparison of thrust.

 

[hutchphd]

It's frightening how much wealth and power are in the hands of one man, especially one with crackpot notions.

I do not see him as frightening. He has earned his wealth by repeatedly producing very high quality products and services in a variety of fields. One does not produce the extraordinary using ordinary methods. We have survived far scarier past examples
He was not handed his real estate money from daddy to build a quasicriminal enterprise.
He did not build underground factories at Dora/Nordhausen.
He did not peddle addictive substances to children
I could continue ad infinitum

 

[gleem]

And he is doing his part to defer the population stagnation.

 

[bob012345]

It might have been a reality, if Nixon hadn't cut funding to the NERVA project. By the end of 1968 they had already had developed an engine that met the requirements for such an endeavor. It was a lack of political will more than anything else.

Mars did not require a nuclear rocket. I believe after Apollo the reality was that public just did not want to spend the money.

 

[mfb]

Can you discuss Musk in a different thread please? This thread is about a NASA rocket. SpaceX rockets can be a relevant comparison, but the CEO of SpaceX is completely off-topic.

I was searching as far as NASA's fact sheet for the SLS but haven't found a comparison of thrust.

39 MN for SLS (Block 2 will have 41 MN)
35 MN for Saturn V
31 MN for the Space Shuttle
45 MN for N1.
All N1 launch attempts failed, so SLS can become the rocket with the most thrust to ever make it to orbit - and obviously the heaviest operational rocket. Falcon Heavy has 23 MN.

~11 hours to launch. Far less press coverage this time, but we should get into the more active regions of the launch countdown soon.

 

[bob012345]

Godspeed Snoopy!

 

[mfb]

They have problems with a hydrogen line, as a result the tank filling proceeded much slower than necessary. Something is mechanically in the wrong place, they warmed up the line trying to get it into the right spot twice but that didn't work. Still trouble-shooting, looks like a launch time will be towards the end of the launch window even if they can fix it.

 

[mfb]

The launch director hasn't made a final decision yet but the responsible teams propose to scrub the launch attempt. It would be surprising if the launch director overrules that (especially with the Space Shuttle failures in mind).

They can try another attempt on Monday, if that doesn't work then the vehicle will need to roll back to the VAB and there won't be a launch this month.

Edit: Scrub is official now.

 

[.Scott]

They have a launch window on Monday and Tuesday. After that, they would need to wait for at least 2 weeks.

 

[Vanadium 50]

Godspeed Snoopy!

Wasn't that Apollo 10?

 

[bob012345]

Wasn't that Apollo 10?

Borrowed from Friendship 7. "Godspeed, John Glenn"

 

[hutchphd]

Snoopy was Lunar Module for Apollo 10. Godspeed was Scott Carpenter's heartfelt benediction at t=0 in Glenn's countdown

 

[bob012345]

Snoopy was Lunar Module for Apollo 10. Godspeed was Scott Carpenter's heartfelt benediction at t=0 in Glenn's countdown

There is a "passenger" on this new rocket named Snoopy hence the reference.

 

[mfb]

They have a launch window on Monday and Tuesday. After that, they would need to wait for at least 2 weeks.

They had one Monday, but they can't fix the problem in these two days and with the rocket on the pad.

NASA to Stand Down on Artemis I Launch Attempts in Early September, Reviewing Options

There is a range of launch windows September 19 – October 4. That can only be met if the rocket doesn't have to go back to the VAB. That means extending the certification of the flight termination system and fixing all issues with the rocket on the launch pad.
The following range is October 17 – October 31.

 

[neilparker62]

He seems to me like a mad megalomaniac, who believes we're living in a computer simulation from the future. It's frightening how much wealth and power are in the hands of one man, especially one with crackpot notions.

Others, no doubt, will see him as mankind's saviour.

On the whole I think I prefer Elon firing his rockets towards Mars than others firing hither and thither here on Earth. Space is where effort and energies should sensibly be spent. So roll on Elon!

 

[Buzz Bloom]

I would much appreciate it if someone would make clear what the following abbreviations mean: MN and N1.
The reference is from post #56 by @mfb.
39 MN for SLS (Block 2 will have 41 MN)
35 MN for Saturn V
31 MN for the Space Shuttle
45 MN for N1.

 

[Ibix]

I would much appreciate it if someone would make clear what the following abbreviations mean: MN and N1.
The reference is from post #56 by @mfb.
39 MN for SLS (Block 2 will have 41 MN)
35 MN for Saturn V
31 MN for the Space Shuttle
45 MN for N1.

N1 was a Soviet rocket that was supposed to be comparable to the Saturn V, but kept exploding. MN is mega Newtons of thrust, I imagine.

 

[.Scott]

It's an interesting cultural difference between SpaceX and NASA in that what would be a failure for NASA is a 'test to failure mode to learn" experiment to SpaceX.

It's mostly a difference in tempo. When SpaceX RUDs, they already have the next one in the works. If NASA/Boeing RUDs with the SLS launch, it would literally take an [unlikely] act of Congress to recover.

At this point, a real SLS setback would be not launching before Starship. Elon has said that the Starship launch will happen this year - though he acknowledges that SpaceX has a reputation for turning the "impossible" into "late". He has already booked the first paying Starship launch for 2024.

I'm fully expecting Artemis 1 to launch on SLS first. But it's far from a certainty.

I am also fully expecting that there will two successful Starship launches by the end of 2023. And that's when the Starship vs. SLS comparison will become very hard to ignore. NASA wants both to succeed, but at some point it could start looking like the crew missions to ISS - where SpaceX chalks up several missions before the competition makes their first.

 

[.Scott]

It looks like: Set up shop at the pad; With the cryo plumbing available at the pad, explore and perhaps fix the problem; bring SLS back to the VAB for recertification; redeploy to pad; wait for a launch window and avoid conflicts with ISS launch activity.