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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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Today is Google Meeting Day for NewMars...
This is an opportunity for us to put into motion the plans we've been thinking about, for an Iterative Rocket Design process to be applied to at least three interesting rocket designs. All are SSTO, because TSTO is so well established.
SSTO remains a frontier of human achievement.
Our current options include:
1) A Carbon based concept, led by kbd512
2) An LH2 based concept, led by GW Johnson
3) A hybrid Carbon and LH2 concept, led (for the moment) by tahanson43206
Another interesting concept is waiting in the wings....
That would be a lifting body designed for multi-phase propulsion:
1) Railroad acceleration to 320 m/s
2) Rocket acceleration to ramjet speed
3) Ramjet acceleration while atmosphere supports it
4) Rocket acceleration added to ramjet until 100% rocket
5) Rocket acceleration to finish LEO
An interesting feature of this design is the option to try a Tangent Trajectory.
Tangent Trajectory was first discussed several years ago by kbd512, and it was recently brought back into view by GW Johnson as a part of his studies of various ellipses for space navigation.
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Systems check at 22:31 UTC went well.
We are on track to open the waiting room at 24:00 UTC 7 PM Houston 8 PM New Hampshire.
The main item I am hoping we can take up is the opportunity we have to embark upon an Iterative Rocket Design process for the three SSTO configurations on offer.
In light of the limitations of the forum software, I am unsure of how we might be able to make this happen so that our readers can follow along. GW Johnson normally does all his work on a personal computer without online connection. I am hoping we can find a way to carry out the process in steps small enough that our readers can follow along.
This ** is ** rocket science, and trying to make it accessible is a challenge.
Update: The waiting room is open at 23:57:25 UTC
Post meeting report:
kbd512 was in fine form this evening. We discussed a wide range of topics as usual.
A highlight for me was a deep dive into the difference between coil guns and rail guns. The magnets are wound at 90 degrees to each other.
There are other differences as well. kbd512 may be able to write a post to explain the difference, and if he does I'll create a bookmark in our new Bookmarks topic so folks can find it easily in future.
We also spent a good amount of time looking at Calliban's rock tumbler, thanks to the images that Calliban provided showing his progress on the machine.
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For kbd512 ahead of Google Meeting Sunday....
There is interest in SSTO in the forum, and since there appear to be no successful systems in existence on Earth in 2025, the topic is open to everyone to try to think of how it might be achieved.
It occurred to me that while we know of the British renewed interest in their concept, perhaps there are other initiatives around the world.
If you have a few minutes, please see if you can find any/all examples of SSTO initiatives.
We might even include RGClark's initiatives for comparison with PhotonBytes and yours.
PhotonBytes is (apparently) trying for full reusability, and that is quite a leap from simple expendable designs that would deliver the rocket itself to orbit as raw material for industry.
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For those planning to attend Google Meeting Sunday.
In case GW Johnson can't make it, he provided a document at AirLaunch folder on my system.
I'd like to review the offer I made to let PhotonBytes recruit employees in posts on this forum.
<> I'd like to review the option of creating a hidden category for topics members might want to discuss that are unsuitable for a global audience.
A model of what that looks like is the Projects category SpaceNut created to let members work on projects with visibility to members but not guests.
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Google Meeting equipment check went smoothly at 22:57 UTC
The waiting room will open a bit before midnight UTC, 7 PM Houston, 8 PM New Hampshire.
Recent posts by PhotonBytes are added to the agenda.
*** Update after meeting...
Wow! That was a jam packed meeting.... GW Johnson and kbd512 were both in fine form.
We used the Google Meeting collaboration tools to cover a number of topics in depth.
We opened with one of GW's papers, and that led to deep dives into air launch systems. Kbd512 is familiar with modern attempts to perform air launch so we looked at some of those.
The hour flew by so quickly, as I think back, we may have devoted the entire hour to that subject. GW reminded us of history of US attempts to combine rockets with jet engines or ram jet technology to achieve orbit from a flying platform.
*** note for PhotonBytes.... I offered the group a chance to look at your offerings, but there was nothing to choose from that was appropriate for the venue. You've certainly offered a lot of material, but it was not organized for an online meeting.
You can look at GW Johnson papers and presentations if you want to learn how to prepare materials for an online audience.
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I was reminded that a washing machine for space zero g would be something that should be with a patent. It was a small concept that RobertDyck and I worked to flesh it out in a topic long ago.
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