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System test at UTC 22:44:28 went well
We're on schedule for opening at 23:58 UTC
Post meeting follow up ...
Well! That was intense... Great meeting....
We opened with kbd512 and a review of recent posts about hydrogen in the forum
GW Johnson arrived and we spent a few minutes looking at a slide show of drawings GW has prepared to show various launch configurations. The images have not been posted on the forum because we are still dealing with a blockage at imgur.com, and have not yet found a solution that works for us.
kbd512 and i briefly discussed that issue.
The next phase of the meeting was devoted to delivery of software to GW's laptop, where we established that while the files are present, they will not run on his 64 bit computer.
However, GW has several 32 bit machines in storage, and he might be able to bring one of them back to life.
In the mean time, I'will continue porting that ancient software to modern Visual Studio. My first attempt produced hundreds of errors, but they all look solvable. It's just a question of taking the time.
For just one trivial example, the command "print" in 1990 DOS BASIC is now console.write("text to write)
Since this is a running program, I am confident it can be brought forward (kicking and screaming no doubt) to 2019, and from there it will be a hop-skip-jump to 2022, which is the current level of the free Visual Studio package.
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Google Meeting Day for NewMars....
The waiting room is due to open a few minutes before Midnight UTC, 7 PM Houston, 8 PM New Hampshire time.
With any luck we might have a fruitful discussion of SSTO in light of GW Johnson's recent study showing a LH2/LOX SSTO appears to be feasible with existing rocket engines. In preparation for the meeting, I am hoping all participants will reread the paper, so we can spend as much time as possible advancing the vision of a practical non-reusable SSTO design that can deliver payload and itself to LEO. The material used to make the SSTO should be usable for on-orbit construction. If that can be achieved, then the waste is reduced, and the only expense is fuel.
https://exrocketman.blogspot.com/search?q=ssto
Or to the exact article: https://exrocketman.blogspot.com/search?q=11032024
Update: System check at 18:25 New Hampshire time went well.
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tahanson43206,
I've still seen no response to the fact that RP1 very clearly provides a lot more Newton-seconds of total impulse per unit of dry stage mass, as compared to LH2. A Falcon 9 Block V booster core with sea level Merlin-1D gas generator engines and the reusability hardware attached still delivers 48% more Newton-seconds of total impulse, per kilogram of dry stage mass, using sea level thrust / Isp values, as compared with a pair of RS-25D staged combustion engines attached to a notional re-powered Delta IV Common Booster Core, when the basis of comparison is with the RS-25D's Vacuum thrust / Isp figures.
For any rocket, Newton-seconds of total impulse per unit of dry stage mass determines how much payload you can deliver to orbit. More total impulse per unit of dry stage mass is "more better", especially for a SSTO, which is carrying the entire vehicle mass all the way to orbit with the useful payload.
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Google Meeting is set up ...
I am seeing intermittent Internet blockage...
Not all sites seem to be affected by Mars Society is non-responsive at times
Note: kbd512 pointed out that a sea level will produce more thrust at 100,000 (higher altitude) because there is less back pressure from the atmosphere.
Next we discussed turbopumps...
When the engine is generating flow rate it doesn't change during the flight. The only thing that changes is the amount of thrust that the engine generates as the atmosphere back pressure decreases.
Next: if you want SSTO, you have to maximize the total impulse per unit of dry mass. This is measured over the entire flight.
The thrust increases as the vehicle ascends because the backpressure decreases and the rate of velocity change will increase as the mass of the vehicle decreases.
Additional item: kbd512 showed examples of fiber optic guided drones. Apparently the fiber can be spooled for a couple of miles.
kbd512 thinks the range might be as great as 5 miles.
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Today is Google Meeting day for NewMars.
Yesterday's hybrid combined meeting of two NSS chapters in Houston was a success by every measure.
The online experience was enhanced with an additional camera.
The audio and video worked well for presentations.
The new Master of Ceremonies handled the duty well.
There was a nice attendance at the library and online.
Next meeting will be held at the Clear Lake facility.
The main presentation was on a Space Studies activity of an international nature.
***
In today's NewMars meeting, we have the opportunity to begin long deferred work on design of an actual SSTO.
We have at least three competing proposals.
kbd512 advocates an all-Carbon fuel approach, so he will have the lead for that version.
GW Johnson has shown through calculation that an LH2 version will work.
tahanson43206 offers a hybrid concept, with both Carbon and LH2 as was done with the Space Shuttle and is being done with Vulcan.
We will (no doubt) have other topics for discussion as well.
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Systems check went smoothly at (about) 2300 UTC...
I'll open the waiting room a bit early since the system is runnng ...
Open at 23:54:12 UTC
kbd512 and GW Johnson joined...
Discussion opened with the Carbon SSTO concept in play on the forum recently, and pretty much stayed there for the entire hour and fifteen minutes.
Update: I have completed my two homework assignments.
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