The Hidden Troubles of the F-35 [DefenseNews]

Discuss the F-35 Lightning II
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blindpilot

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Unread post08 Feb 2021, 20:40

zhangmdev wrote:... Those old days of Apollo and Space Shuttle, when software was developed by a very small number of people for a very specific system, when stuff was done in thousands of lines of code, are never coming back.


That may be true, but I would take a group of Musk hired programmers using Algol and PERT charts standing on their heads, and hand soldering the new chips in, ... over any typical group of software engineers currently using the latest greatest COTS favorite approach if I was the one flying the craft to ISS.

And you know what ... I'll bet there isn't a single person here who would choose Starliner over Dragon if they were the ones going up. And the biggest reason that is true is Musk hires talent, period ... and uses diplomas and NASA/Industry system approaches as restroom resources. At least he pretends to treat NASA assistance with grace, but don't bet he thinks FAA et al brings anything to the table for Mars tomorrow. He's just being nice.

SpaceX, for example, is "coming back," in every way that matters.

MHO anyway,
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zhangmdev

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Unread post08 Feb 2021, 21:45

But don't lionize SpaceX too much. It has its own special blunders. Demo Mission-1 Crew Dragon developed a propellant leak during a ground test, which was overlooked and destroyed the capsule instantaneously and completely. Subsequent re-design and re-certification pushed back its first manned flight for a year. That accident was not software-related, but costly and potentially deadly nevertheless.
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Unread post08 Feb 2021, 22:01

...but don't bet he thinks FAA et al brings anything to the table for Mars tomorrow. He's just being nice.


The much maligned FAA. They don't care who or what table he sends to Mars. 'Experimental' has a lot of leeway with the proper signed release forms.

However, they are concerned about and for the 'burbs' in any flight profile where any wreckage might fall. Texas, in spite of recent indications, is not all tumbleweeds.
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XanderCrews

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Unread post08 Feb 2021, 22:25

outlaw162 wrote:
...but don't bet he thinks FAA et al brings anything to the table for Mars tomorrow. He's just being nice.


The much maligned FAA. They don't care who or what table he sends to Mars. 'Experimental' has a lot of leeway with the proper signed release forms.

However, they are concerned about and for the 'burbs' in any flight profile where any wreckage might fall. Texas, in spite of recent indications, is not all tumbleweeds.


Yeah its f**king east California now.
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blindpilot

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Unread post09 Feb 2021, 05:13

zhangmdev wrote:.....Some fancy cars these days could be running on more than 100 million LOC. That is how incredibly bloated modern software has become..... Those old days of Apollo and Space Shuttle, when software was developed by a very small number of people for a very specific system, when stuff was done in thousands of lines of code, are never coming back.


Wrong. Watch the you tube video Sandy did with Elon. [ https://www.youtube.com/watch?v=YAtLTLiqNwg ] Quotes on the Tesla AI self driving stuff -
"done by a very select group of hand picked talented individuals ... " "I incentivise 2 points for deleting a line of code and 1 pt for writing a line that is used." " I don't know how many lines the AI parts are but not that many, say a couple hundred thousand lines maybe?"

But yes we shouldn't Lionize SpaceX, but I bet everyone here will buy stock in it at any price when it goes public. The "Rapid Unscheduled Disassemblies" are an intentional prototyping style . One NASA used in the 60's and one SpaceX does without apology today. Musk budgets the RUDs (explosions) and only gets excited when they don't result in progress.

Tell you what. Buy Boeing stock, set up your millions of lines of ISO 9001 programming code, use pretty fancy colored paper and special fonts for your reports. I'll follow the SpaceX line myself.

As to the F-35, millions of lines, Lockheed product. Lockheed has always had little gnomes they keep in the basement(like Skunk works) and feed them pizzas to keep projects from blowing up in their face. But they have the same issues as Boeing ... except for the gnomes. And that's my point. Full disclosure, I do own stock in Lockheed ... because of the gnomes.

One of the last consulting jobs I did for Verizon ended the report with something like, "do whatever you think is pretty for the board and outside world, but DO NOT touch the gnomes in the basement! They are why you are still in business." (and yes I own Verizon stock too, ... because of the gnomes in the basement :D )

FWIW MHO,
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zhangmdev

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Unread post09 Feb 2021, 08:08

The "AI", or Neural Network/Machine Learning, stuff is largely data-driven. The program is relatively simply, but it requires maybe Petabyte of input to "learn" the useful configuration. And most ML project relies on some midware like TensorFlow to do the heavy-lifting in the background. Those are open-source projects maintained by a community. The coding on the specific application side is light. It is all about data. Data collecting and processing is expensive. I talked about that issue in the AI vs Human Pilot thread on this site.

The SpaceX accident mentioned is

https://spacenews.com/faulty-valve-blam ... -accident/

The capsule was not a prototype. It was fully functional and finished the trip to the ISS and back. It was not intended to be tested to destruction on the ground. The plan was to test and certify the abort engines first, then used it during the in-flight abort test, in which it will not be destroyed either. It should escape and land safely. The booster will be destroyed. After losing the DM-1 capsule, they had to made a new one for the in-flight abort test, with re-designed abort system. It is worth to mention that leaky valve was put into the system because SpaceX's goal to use abort engines for propulsive landing. NASA doesn't need that feature, but the valve was still there, and turned into a failure point. After redesign, the valve was replaced by burst disc, which makes those engines single-use, eliminating the possibility of propulsive landing. Kinda like what often happens in the software development, obsolete and useless left-over from the past is forgotten then turns into serious bug hard to find.
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Unread post09 Feb 2021, 17:54

zhangmdev wrote:The "AI", or Neural Network/Machine Learning, stuff is ...... Kinda like what often happens in the software development, obsolete and useless left-over from the past is forgotten then turns into serious bug hard to find.


All true, but listen to Elon's chat with Sandy. He scores X 2 for programmers who find and delete those very leftover useless lines. That is not exactly a software bloat approach.

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