Boeing again 47

[3DDave]

Per Wikipedia

The propellant had an 11-pointed star-shaped perforation in the forward motor segment and a double-truncated-cone perforation in each of the aft segments and aft closure. This configuration provided high thrust at ignition and then reduced the thrust by approximately a third 50 seconds after lift-off to avoid overstressing the vehicle during maximum dynamic pressure (max. Q).

So all joints would have the same burn exposure. It appears that most erosion events happened at the same field joint, the one near the nozzle.

Relevant discussion:

https://www.nasa.gov/history/rogersrep/v1ch6.htm

 

[Alistair_Heaton]

https://www.goodreads.com/book/show/5070507-truth-lies-and-o-rings

This book has alot of technical detail about the engineering of what happened.

 

[Oops409]

Here is a link to a 1986 Article in the Los Angeles Times, entitled: "NASA Rejected Seamless Rocket to Save Money"

DoD does not use segmented solid rocket motors. The O-Ring Failure Problem is the reason why. Aerojet was the only contractor offering a non-segmented design out of the 4 contractors and was the technical design chosen first by the SSEB Evaluation Team.

But then Politics enters the engineering world every day, especially in Government Contracts.....

The board rated Morton Thiokol least capable contractor from a technical standpoint, but the cheapest from a cost standpoint.

The Key Politicians in control that day wanted Morton, therefore Management at NASA overruled their source selection evaluation board's choice of AeroJet, and selected Morton Thiokol.

This is how Engineering Works in the US Government...... Engineers are fired on a regular basis if they don't justify what politicians and thus management wants the answer to be.

https://www.latimes.com/archives/la-xpm-1986-02-15-mn-8154-story.html

 

[3DDave]

Four companies submitted bids to build the solid rocket boosters for the Space Transportation System based on the requirements provided by the Space Shuttle Program.

Three of the designs were segmented cases to expedite transport of the boosters from the factory. However the fourth bidder Aerojet submitted a proposal for an unsegmented case.

The Aerojet proposal was rejected specifically because of its case design.

The strength of the case was found inadequate for the prelaunch bending moment loads and was not designed with an adequate safety factor for water impact loads

Of the four proposals, the ones selected for final consideration were those of Thiokol and Lockheed (both segmented case designs). Lockheed was preferred on technical matters, but Thiokol was preferred on management and cost.

There was controversy over the selection of Thiokol over Lockheed, especially because the NASA administrator was from Utah (home of Thiokol) as was a powerful senator who chaired the Senate space committee. Lockheed unsuccessfully protested the award.

However, note that this controversy was between two segmented designs.

Bottom line, segmented cases were used in the design because most of the solid rocket motor manufacturers of the time felt that such a design would meet the requirements best. The contract managers at NASA agreed and selected one of the segmented designs.

Reference: Development of the Space Shuttle, Heppenheimer, pp 71-78

 

[Oops409]

The strength of the case was found inadequate for the prelaunch bending moment loads and was not designed with an adequate safety factor for water impact loads

For anybody who lived thru government proposal evaluation process, knows that you don't dermtermine from paper proposals whether a design meets specification or not.

For anybody to make such a statement, means they don't understand the government procurement process.

It is common for government organizations to bias requirements documents, to favor one party over the others. This is exactly what NASA did to eliminate the best and safest solution.

 

[dik]

...and typical with government, no one was held accountable.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[IRstuff]

It is common for government organizations to bias requirements documents,

It's common, period; lots of private companies do the same.

However, in the case of aerospace and defense, it's not always a simple choice, because you, as the government, do not want to be beholden to a single contractor. Therefore, even if it's not necessarily the most optimum solution, you may decide to award a contract to someone else, for the following reasons:
> maintaining a "competitive" market
> ensure that there is at least one viable alternate that could potentially be a second source
> ensure that there is at least one viable alternate so that there is price competition

So while Boeing might have been a poor choice, it might have been necessary to ensure that SpaceX doesn't become the sole survivor and a single source.

Note also, SpaceX has gotten gobs of government funding and contracts, despite claims to the contrary

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[TugboatEng]

...and typical with government, no one was held accountable

Now you're seeing the light!

 

[dik]

I was aware of it at the time and was surprised that no one filed and engineering association complaint.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Oops409]

Agree no one is held accountable and tax payer dollars just pay the cost overruns. Yes multiple sources are always preferred but in most of the NASA/DoD Programs I worked on or managed, we did not have the luxury of having the funds to cover two competing development contractors for same mission.

Early in concept phase there could be competition but never through the who process. Typically the government wanted to own tech daya packsges and eliminate proprietary hardware and software. But reality and avsilable program funds typically dictated the government did not buy the tech data packages, nor eliminate proprietary sole source hardware, firmware and software.

Just like Boeing signed a firm fixed price contract without changing the cost plus fee structure they grew up on.

 

[JohnRBaker]

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Alistair_Heaton]

Popped up in my news feed.

https://cleantechnica.com/2024/08/2...-boeing-and-with-them-much-us-climate-action/

Seems it's all linked to the same people.

 

[1503-44]

We used to keep competition viable by occasionally awarding offshore pipeline contractors a job, as long as they were not very far away from the low bidder's price. There were so few contractors at the time that, if anybody went out of business, it would mean hefty price increases for everyone next season.

One would not really want companies with high strategic value to go out of business either. Buying stuff from potential adversaries is not a good position to be in. You really need to home grow as much of this stuff as possible.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[3DDave]

Nothing like an unbiased article mixing some facts with a lot of fiction tied together with outrage.

 

[btrueblood]

John, star for those photos and the reminder to stop there on my next trip down I84/I15.

 

[JohnRBaker]

Yes, for nerdy engineers, it's well worth the stop. And it's also an 'advert' for watching out for those 'Brown Signs' on the interstate, often highlighting obscure places to visit which often prove to be more interesting than the more famous ones. My friend Dennis and I made it a point to watch for those 'Brown Signs' during our many trips together. In addition to the 'Rocket Park' we discovered that the geographical center of the United States had moved from where we had learned it was at when we were in school. It's now near Belle Fourche, South Dakota:

October 2009 (Sony A100, 18-70mm)

We also discovered the tallest 'structure' in North America, the 2,063 foot tall KVLY-TV antenna near Blanchard, North Dakota:

April 2019 (Sony a6000, 10-18mm)

Or an old Minuteman Missile command center, which is now open to the public, near Cooperstown, North Dakota. This was of special interest because my friend Dennis, who when he was a Captain in the Army did an exchange tour with the Air Force, manning a Titan II missile command center in Arizona:

April 2019 (Sony a6000, 10-18mm)

Or that there are actually TWO Continental Divides in the United States, the second one found near Browns Valley, Minnesota:

April 2019 (Sony a6000, 16-50mm)

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[ChorasDen]

Those are cool stories and photos, particularly the antennae, thanks John.

 

[3DDave]

Why is there a guy in the Michigan Tech jacket sneaking into all the photos? Is he there for scale?

 

[hokie66]

There are 6 Continental Divides in North America, and 5 of them go through the US.

https://www.magellantv.com/articles/what-is-the-continental-divide-and-why-is-it-important

 

[Oops409]

I stumbled upon this on NASA's Public Relations Site. While it is Great for this person, that a Communications Major was able to land a Project Management Position at NASA, it also shows organizations don't value technical folks as highly as MBA types or in this case a Communication Major'.... Yet without the techie's none of this happens.

Another reason why folks don't choose the tougher technical path in college, and the US does not graduate enough engineers and scientists. Heck I would have taken the easier path if I had known in the end it would pay more than an engineering path.....

Then the kicker is NASA promoting putting the first woman and first person of color on the Moon as their Mission Statement. So a person's sex and race is more important qualification than merit or the actual scientific mission?

Excerpt from article below with link to article below that:

"It led him to his current one as project manager for the ICPS (interim cryogenic propulsion stage) for NASA’s SLS (Space Launch System) Program, which is managed by Marshall, and will help NASA land the first woman and first person of color on the Moon under Artemis."

https://www.nasa.gov/people-of-nasa/i-am-artemis-cody-jones/