This was the comparison I was talking about, @Astranutfresh_42 said:
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 examplesPeroK said:It's frightening how much wealth and power are in the hands of one man, especially one with crackpot notions.
Mars did not require a nuclear rocket. I believe after Apollo the reality was that public just did not want to spend the money.Janus said: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.
39 MN for SLS (Block 2 will have 41 MN)fresh_42 said:I was searching as far as NASA's fact sheet for the SLS but haven't found a comparison of thrust.
Wasn't that Apollo 10?bob012345 said:Godspeed Snoopy!
Borrowed from Friendship 7. "Godspeed, John Glenn"Vanadium 50 said:Wasn't that Apollo 10?
There is a "passenger" on this new rocket named Snoopy hence the reference.hutchphd said:Snoopy was Lunar Module for Apollo 10. Godspeed was Scott Carpenter's heartfelt benediction at t=0 in Glenn's countdown
They had one Monday, but they can't fix the problem in these two days and with the rocket on the pad..Scott said:They have a launch window on Monday and Tuesday. After that, they would need to wait for at least 2 weeks.
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!PeroK said: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.
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.Buzz Bloom said: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.
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.bob012345 said: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.
From what I have read, the purpose in doing the work at the pad is to actually work the problem with the plumbing attached.mfb said:NASA wants to fix the hydrogen issue with the rocket on the pad. That could allow a launch in the second half of September, and it will mean more time for tests with the rocket and the launch tower. Downside: The certification for the flight termination system runs out and they can't access it, so this plan only works if they get an extension. This is not a new constraint - I would expect that NASA applied for it long ago. Would be a strange coincidence if the normal process was almost done just at the time they need it, so I'm not sure what's going on.
If they don't get that extension the vehicle needs to roll back.
After the launch was called off, NASA Administrator Bill Nelson said the rocket's next launch window will open in early October, but because other missions will be prioritized over Artemis 1, the third launch attempt likely will fall in the middle of the month.
Up until Sept. 17, it's been on the pad because the leak is at the Rapid Disconnect seals. They have needed at the pad to see the problem and repair it. It needs to remain there until the repair is tested (now scheduled for the 17th).mfb said:NASA wouldn't keep the rocket on the pad if they were not pretty confident to get that extension.
Repair work is ongoing and they want to a test tanking next Saturday.
9/27 would put the battery period at 46 days. Space Force needs to start with the assumption that there is no FTS until demonstrated otherwise. So they could clear the launch without a VAB visit if it can be safely done with no FTS (not a prayer) or if there is solid reason to believe that the FTS would work (sound like a stretch to me).But avoiding a rollback is dependent on the Space Force: the military branch is responsible for public safety and requires the rocket's flight termination system, or FTS, be recertified every 25 days. The current certification for the FTS, which is designed to destroy the rocket in the event of an emergency, expired Sept. 6.
Officials said they submitted FTS extension requests with the range and are waiting for a response.
I don't see that happening. The rocket is big and you can't shut down the SRBs. If the system breaks apart and can't be destroyed they could end up anywhere..Scott said:So they could clear the launch without a VAB visit if it can be safely done with no FTS (not a prayer)
NASA wouldn't plan with an extension without good arguments for that. But I don't understand why they weren't pushing for a longer certification period earlier..Scott said:or if there is solid reason to believe that the FTS would work
I don't either. And I'm wondering whether the reason that Space Force hasn't put a quick kibosh to a 45-day extension is that after the next cryo test it could become a 65-day extension. NASA's been struggling with LH2 leaks for decades.mfb said:NASA wouldn't plan with an extension without good arguments for that. But I don't understand why they weren't pushing for a longer certification period earlier.
Perhaps NASA's history with LH2 might steer you toward a more pessimistic launch date.mfb said:No official word yet, but I have heard that there are two ways forward ...
6 attempts to fill the rocket on the pad, 6 hydrogen leaks despite repairs between the attempts..Scott said:The LH "stop flow" was triggered by a hydrogen leak.
At 10:13: The "leak team" has just reported to the launch director that the leak profile is identical to the leaks during those previous attempts. They will attempt to cycle temperatures in an attempt to better seat the connection. Next attempt around 10:45am.mfb said:6 attempts to fill the rocket on the pad, 6 hydrogen leaks despite repairs between the attempts.
Why do things not work these days? Perhaps that's an unfair assessment?.Scott said:At 10:13: The "leak team" has just reported to the launch director that the leak profile is identical to the leaks during those previous attempts. They will attempt to cycle temperatures in an attempt to better seat the connection. Next attempt around 10:45am.
NASA has never "mastered" LH fueling - in the sense that they can created results that matched the design intent on the first try.PeroK said:Why do things not work these days? Perhaps that's an unfair assessment?
I have heard today about regulations here concerning fire prevention after a major fire at an airport years ago. Someone commented on them as overregulation that hinders efficiency too restrictively. I could imagine that NASA suffers similar problems after the shuttle disasters.PeroK said:Why do things not work these days? Perhaps that's an unfair assessment?
It doesn't sound "too restrictive" to me. The LH leak limit is 4%, they are seeing "7% concentration". I have not been able to find an exact and explicit description of what the numerator and denominator are in that 4% limit. However, this LH leak is into an environment rich in O2 - because the LOX also leaks and because there is O2 condensation.fresh_42 said:I have heard today about regulations here concerning fire prevention after a major fire at an airport years ago. Someone commented on them as overregulation that hinders efficiency too restrictively. I could imagine that NASA suffers similar problems after the shuttle disasters.
That's the Lower Explosive Limit(LEL) volumetric (and molar) concentration for hydrogen. That they exceeded it means they had an explosive mixture. Really dangerous..Scott said:It doesn't sound "too restrictive" to me. The LH leak limit is 4%, they are seeing "7% concentration". I have not been able to find an exact and explicit description of what the numerator and denominator are in that 4% limit.
It's the H2 concentration in the LH QD Cavity. There are two mitigating issues regarding an explosion: 1) That cavity has no ignition sources. 2) The equipment in that region is pretty rugged - a moderate H2 "explosion" could be taken in stride.russ_watters said:That's the Lower Explosive Limit(LEL) volumetric (and molar) concentration for hydrogen. That they exceeded it means they had an explosive mixture. Really dangerous.
