John Krell

[John Krell @JohnKrell7]

@mclumber1 @DJSnM The F9 and New Glenn are subsonic when they relight the engines for landing. The engineers let the atmosphere deplete as much velocity as possible.

[John Krell @JohnKrell7]

@joebarnard I know the feeling. I fly on average 3 rockets per month, collecting flight dynamic data at 1KHz. This month the data rate goes up to 2KHz. A mountain of data generating even more data results for clients with 5KHz and 10KHz systems in testing.

[John Krell @JohnKrell7]

@steveflyzz @SciGuySpace I was a member of an ozone balloon flight. The control room received a call from the FAA requesting ground coordinates and altitude. A commercial flight had reported a near miss. The ground coordinates were correct for the balloon, but the balloon was at 87,000.

[John Krell @JohnKrell7]

For years I was told that it was impossible to detect a model rocket ignitor firing. It imparted too small of a force over an insignificant length of time. What value would it be to the rocket's flight?
Data does have value and beauty.

[John Krell @JohnKrell7]

@SydSteyerhart Our family doctor in 1980 told me to stop taking Tylenol due to its toxic liver metabolic components.

[John Krell @JohnKrell7]

The low-resolution Starship flight 10 performance data comparison is interesting. The hot staging negative acceleration caught my attention. Plus, the maximum acceleration of the Starship just prior to suborbital insertion velocity. SpaceX is truly testing the limits of Starship.

[John Krell @JohnKrell7]

It took me 5 months to develop my first 500Hz model rocket flight computer. It took another 5 years to develop a 1000Hz system. I had to wait on technology, but 1 week after losing the 1000Hz system I reached 2000Hz. Knowledge + motivation = advanced results.

[John Krell @JohnKrell7]

@Snikinuli @DJSnM Hydrogen Peroxide + solid fuel = no explosion

[John Krell @JohnKrell7]

@dcoffin @DJSnM @ShorealoneFilms 98% hydrogen peroxide isn't as volatile as LOX, plus no liquid fuel to mix with it.

[John Krell @JohnKrell7]

@DJSnM It appears that one of the electric motor turbo pumps failed as the vehicle was released. There could be other issues including debris in the HTP. If they pre-decompose the HTP before injection it could be a catalyst pack issue.

[John Krell @JohnKrell7]

@joebarnard Just a 16x102 tool lathe. I machined my first "cold gas" engine on one.

[John Krell @JohnKrell7]

@patframe04 @joebarnard Not how to make nozzles but they did forget about the magnitude of stresses on the gimbal flex seals.

[John Krell @JohnKrell7]

@Pad33space In 1977 I was purchasing AP at $1.25 lb.

[John Krell @JohnKrell7]

@milindS_ @Pad33space I doubt it is collecting data faster than 200Hz, when they could be collecting data >1000Hz.

[John Krell @JohnKrell7]

@dfingles1 @DJSnM I've used lithobraking at 144 m/sec. Stopping in 16ms generating 900 G average deceleration and everything survived.

[John Krell @JohnKrell7]

@Pad33space @rocketsdsu Did they recover the rocket?

[John Krell @JohnKrell7]

@grok @CWilliamAshby @DefiyantlyFree At the rate the charging stations are being built, it will be 2360 when the project is completed. About the same year the High Speed Rail line will be completed in California.

[John Krell @JohnKrell7]

@SomethingThWise @astro_Pettit Yes

[John Krell @JohnKrell7]

@erixfilming @Degen_Zee @elonmusk @SpaceX 50 miles above the plane and 150 miles to the south of the plane.

[John Krell @JohnKrell7]

@joebarnard My longest run was a half-marathon. I ran a 4:17 mile in high school and sub-6 minute miles into my 50's.