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After a decade, NASA’s big rocket fails its first real test

arstechnica.com

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Re: After a decade, NASA’s big rocket fails its first real test

#131

Post by sidlls »

pfdietz wrote: post #106
sidlls wrote: post #97

Earlier quoted context omitted.

And I’m tired of seeing people worship private entities whose entire success story is dependent entirely on government work. Not just funding, but work (e.g. past research). A business that lives only with government support is a de facto government entity. Sorry that facts offend you.

You seem to be confusing a program that exists because of the government funding the development, and a commercial program that exists in part because the government is one of the buyers of its product. Falcon 9 certainly benefited from the government buying launches, but the project was done with private investment. This is very different from how Atlas, Delta, the Shuttle, etc. were developed. NASA (and DOD) contin…

You seem to be deliberately ignoring the parts of my comments that aren't concerned with funding/money at all.

Re: After a decade, NASA’s big rocket fails its first real test

#132

Post by pfdietz »

sidlls wrote: post #131
pfdietz wrote: post #106

Earlier quoted context omitted.

You seem to be confusing a program that exists because of the government funding the development, and a commercial program that exists in part because the government is one of the buyers of its product. Falcon 9 certainly benefited from the government buying launches, but the project was done with private investment. This is very different from how Atlas, Delta, the Shuttle, etc. were developed. NASA (and DOD) contin…

You seem to be deliberately ignoring the parts of my comments that aren't concerned with funding/money at all.

Your objection seems to be utterly without merit, in that case. Oh noez, SpaceX sold rockets to NASA, so nothing it did is admirable!

And most Falcon launches are not for the government, you know.

Re: After a decade, NASA’s big rocket fails its first real test

#133

Post by mbrodersen »

beerandt wrote: post #63
ryandrake wrote: post #52

Earlier quoted context omitted.

NASA probably could be as nimble as SpaceX if they didn’t have to rely on Congress, whose goal is not to build a successful rocket, but to spread the money funnel across the States. Imagine if SpaceX’s board suddenly said “the company’s goal is now not to get to Mars, but to employ as many people and contractors as possible in all 50 states!” You’d basically get NASA.

So basically... government could be as efficient as the private sector if it wasn't government?

The private sector fails all the time. The problem is not government/private. The problem is large organisations with wrong incentives.

Re: After a decade, NASA’s big rocket fails its first real test

#134

Post by mbrodersen »

Animats wrote: post #54

NASA forgot how to make rockets: “Both NASA and contractor officials explained that nearly 50 years have passed since development of the last major space flight program—the Space Shuttle—and the learning curve for new development has been steep as many experienced engineers have retired or moved to other industries.”

Apparently that wasn’t a problem for SpaceX. The problem with NASA is its corporate culture and political micro-management not lack of engineering skills.

Re: After a decade, NASA’s big rocket fails its first real test

#135

Post by maccam94 »

jbay808 wrote: post #70
maccam94 wrote: post #58

Earlier quoted context omitted.

SLS proponents have been claiming that all of the extra time and money spent on process and formal verification would lead to a rocket that works without having to do lots of trial-and-error like SpaceX. Heck, even the name of the test campaign, the "Green Run," kind of reflects this hubris and shows that NASA expected the tests to largely be a formality.

Doesn't a green run refer to a beginner level course? Like a practice ski hill?

I didn't realize there was any other way to interpret it besides "getting green (successful) results for all of the tests" (there are 8 test stages planned). I think we're both wrong though:

"The term “green” refers to the new hardware that will work together to power the stage, and “run” refers to operating all the components together simultaneously for the first time." --https://www.nasa.gov/exploration/systems/sls/green-run-test-...

I still think these tests should be run more than once though, the RS-25's were originally reusable anyway.

Re: After a decade, NASA’s big rocket fails its first real test

#136

Post by pashamur »

Jabbles wrote: post #42
sandworm101 wrote: post #33

Earlier quoted context omitted.

Then you aren't going up. Rockets are massive tanks of explosives flying through the air at supersonic speeds. That person is there to protect the people on the ground. Launch escape systems will protect the crew, but given the energies involved, the crew is less important than the potential for killing hundreds on the ground, or potentially thousands onboard a cruise ship.

I hope it's actually 2 people like in nuclear missile silos. Is there any public information?

Hey, I wanted to respond to your comment from 18 days ago but responses there have already been disabled (so I'm hijacking this comment). The question was about "> Housing market returns are very bad. Between 1948 and 2004 the real increase in value in the U.S real estate market was less than 1% a year." versus the "Return on everything" paper from 2018. (https://news.ycombinator.com/item?id=25585224)

On page 85 of the paper, they actually point out that the real capital gain is ~0.7-0.9% per year on average (with a huge standard deviation of 8%, since it's very market specific), which seems to agree with the submitted article, but that the rest of the return, 5.33% (stddev: 0.8%) comes from rental yield (of course in the case of your own house that becomes money saved from not paying rent). Those two added together are what give the total rate of return on housing.

Re: After a decade, NASA’s big rocket fails its first real test

#137

Post by akiselev »

pfdietz wrote: post #124
akiselev wrote: post #115

Earlier quoted context omitted.

It easily functions as a self-breeding terrestrial reactor that reaches criticality with 1/500th to 1/1000th the fuel of existing nuclear reactors (~20kg). The design requires active power that shuts down the reactor on failure, making any accident a complete nonevent. It can even be kickstarted without huge amounts of enriched fuel with the addition of a neutron gun (which they used to test the design without nuclea…

The requirements for a space reactor, and for a terrestrial reactor, are radically different. No space reactor will make sense for terrestrial power generation. The temperatures are different, power density is different, safety cases are different. A 20kg reactor likely needs highly enriched fuel (space reactors are typically fast reactors too, so we're talking about something that's almost a bomb there.) An external…

Just read the papers. There are dozens on that archive covering the design, theory, and testing - all of those issues are covered. 20kg is actually a high number optimized for a certain plasma temperature that radiates in UV without losing criticality. All things being equal (enriched uranium hexafluoride), at higher temperatures and pressures the reactor needs far less fuel but it causes too much degradation to the reactor walls to be economical or useful except in cold boots.

The terrestrial reactor and the rocket engine versions are different in how they transmit power from the reactor core to do useful work but not radically so - the core irrotational vortex compressing a high temperature plasma in a single crystal beryllium oxide chamber is the same in both designs and has been tested. The difference is in the cooling gas - hydrogen gas seeded with tungsten nanoparticles to absorb the black body radiation of the plasma for the rocket and water going through a steam turbine for terrestrial power generation.

Re: After a decade, NASA’s big rocket fails its first real test

#138

Post by nickik »

pfdietz wrote: post #125
nickik wrote: post #119

Earlier quoted context omitted.

Had NASA engineers actually build a better design for Space Shuttle, lots of budget would have been available to do more. The Space shuttle could have done much more much better things if it was designed differently.

And had my father had two X chromosomes, he'd have been my mother. There has to be a reason to entertain contrafactuals; you can't just state them and assume that outcome would have been likely.

The point here being that it was not bureaucracy or the government that trapped NASA in LEO. It was NASA own design process.

Blaming everything always on the congress/president is a way for NASA to never take responsibility. All the success gets credit to NASA but failure is always somebody wrong doing.

Re: After a decade, NASA’s big rocket fails its first real test

#139

Post by pfdietz »

Beached wrote: post #105
dblohm7 wrote: post #88

The thesis of this article is pure hyperbole. “Oh noes, one of the RS-25s failed, the whole program is a failure!”

It is widely agreed that the whole program is a failure. Almost 3 years past due date, and most people believe it will still need more than another year. More than double the estimated cost Is providing very little benefit over existing rockets, and providing no benefits over planned rockets in development by others. It is adding no new capabilities, or technologies, and is in fact a step backwards in rocket design,…

Even if SLS delivered the working design instantly at zero cost it would be a failure. The rockets themselves will be too expensive to make and use.

Re: After a decade, NASA’s big rocket fails its first real test

#140

Post by sandworm101 »

JshWright wrote: post #81
sandworm101 wrote: post #13

Earlier quoted context omitted.

>> Staraship: 0.1B dollars worse case scenario (Elon aims at 0.002B$) Lol. No. That is beyond pipe dream territory. There a innumerable costs associated with spacelaunch that have absolutely nothing to do with reusability. Range closures. Payload integration. Regulatory compliance (ie safety). Telemetry. That USAF person in the back of the room with their finger on the destruct button. That stuff doesn't happen for f…

> That USAF person in the back of the room with their finger on the destruct button. That person (the Mission Flight Control Officer) doesn't exist for SpaceX launches, they use an automated system. https://www.unoosa.org/documents/pdf/icg/providersforum/2019...

I hear mixed stories about this. The automated system does exist, but there is also a need to supervise the automated system and so I read that there is still human in/on the loop. The russians suffered an accident tied to a similar system that triggered a launch escape tower prematurely, causing a fire that eventually destroyed the entire rocket on the pad. The flight had been delayed but the system was still activate. After several hours it perceived the slow rotation of the earth as the rocket being off course and triggered.
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