You are not logged in.
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
(th)
Offline
Like button can go here
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.
Offline
Like button can go here
Today is NewMars Google meeting day.
Everyone is welcome to attend. Just click on the link in the first post of this topic.
The waiting room will open shortly before midnight UTC, 7 PM Houston, 8 PM New Hampshire time.
GW Johnson has been busy working on multiple projects.
We'll discuss items that attendees suggest, and if past is prologue, we'll take a deep dive into some technical subject, using the sharing features of Google Meeting to explore web sites under the direction of kbd512.
(th)
Offline
Like button can go here
Systems check went smoothly at 18:43 New Hampshire time.
The waiting room will open a bit before midnight UTC as usual ... 7 PM Houston / 8 PM New Hampshire
The waiting room is open .... 00:00:00 UTC
Well! Some meeting! kbd512, SpaceNut and GW Johnson were in attendance this evening, and we had lively discussion of SSTO, in addition to personal updates as each of us is dealing with challenges of one sort or another.
I am hoping that each of us will be able to work on "homework" during the coming week...
SpaceNut and kbd512 will be looking for actual numbers for (a) gimbal and non-gimbal engine mounts and (b) plumbing to carry fluids from tanks to engines.
GW has completed about 90% of his SSTO estimating work sheet, but needs those two sets of numbers to complete the cycle.
(th)
Offline
Like button can go here
tahanson43206,
Saturn V documentation is incredibly detailed, relative to nearly all other orbital launch vehicles.
Saturn V News Reference - First Stage Fact Sheet
Thrust Structure
The thrust structure is the heaviest of the first stage components, weighing 24 tons. It is 33 feet in diameter and about 20 feet tall with these major components: the lower thrust ring assembly, the center engine support assembly, four holddown posts, engine thrust posts, an upper thrust ring assembly, intermediate rings, and skin panel assemblies.The upper ring provides stability for the corrugated skins around the structure. Four F-1 engines are mounted circumferentially upon the thrust posts and the fifth upon the center engine support assembly. The center engine remains rigid while the others gimbal or swivel, allowing the stage to be guided.
A base heat shield protects internal parts from engine heat, and four holddown posts restrain the vehicle while the engines build up power for liftoff.
The thrust structure supports the entire vehicle weight and distributes the forces of the engines.
Offline
Like button can go here
AI Overview
The Delta rocket family utilizes gimbaled engines to steer the vehicle during launch. The mass of the gimbal mechanism varies depending on the specific engine and rocket configuration, but it generally contributes a small percentage to the overall vehicle mass, typically around 0.1% to 0.5%. The RS-68A engine on the Delta IV Heavy, for example, has a gimbal system that allows for thrust vectoring, enabling the rocket to steer during ascent. While the exact mass contribution of the gimbal mechanism to the RS-68A engine isn't explicitly stated, it's a relatively small fraction of the engine's overall mass.
Here's a more detailed breakdown:
Delta IV Heavy:
The Delta IV Heavy uses three RS-68A engines, each capable of producing 2.1 million pounds of thrust. The RS-68A is a gimbaled engine, allowing for thrust vectoring for steering.
Engine Mass:
The RS-68A is a large engine, and the gimbal mechanism is a relatively small part of its overall mass. The RL10B, used on the Delta IV upper stage, has a mass of 664 lbs and includes a large carbon-carbon nozzle extension.
Gimbal Contribution:
Studies and examples suggest that gimbals typically contribute between 0.1% and 0.5% to the total launch mass. For example, in the case of the Antares 100 rocket, gimbals on the NK-33 engines contributed about 0.16% of the liftoff mass.
Delta II:
The Delta II used the RS-27 engine, and later the upgraded RS-27A, which also employed a gimbaled system for steering. The RS-27A produced 1,054 kN (237,000 lbf) of thrust.
Other Factors:
The mass of the gimbal mechanism can also be influenced by factors such as the size and complexity of the actuators, hydraulic systems, and other associated components
Offline
Like button can go here
AI Overview
Delta family of rockets: engine mount mass
Determining the exact mass of engine mounts within the Delta family of rockets can be difficult because the manufacturer often considers this information proprietary, and rarely discloses it as a separate component. However, related data can be analyzed to infer some insights into their mass:
1. Engine dry mass
Delta IV RS-68 Engine: The RS-68 engine used in the Delta IV Common Booster Core has a dry mass of 6,604 kg.
Delta RS-27A Engine: The RS-27A engine used in the 7000 and 8000 series Delta rockets has a dry mass of 1,091 kg.
Delta II RS-27A Engine: The RS-27A engine featured in the Delta II rocket has a dry mass of 1,146 kg.
Delta IV RL10B-2 Engine: The RL10B-2 engine utilized in the Delta IV's second stage has a dry mass of 301 kg.
2. Structural considerations
Engine mounts, along with other structural components like the motor cases, are designed to withstand the extreme forces and vibrations generated during launch and flight.
Material selection for these components is crucial and includes high-strength options such as steel, aluminum, and alloys like Inconel and Titanium.
3. Comparison with overall vehicle mass
The engine dry mass represents a relatively small fraction of the overall mass of a Delta rocket. For example, the Delta IV Heavy has a total launch mass of 733,400 kg.
Even when considering the mass of the engine mount alongside the engine's dry mass, it would still be a minor portion of the rocket's overall weight.
4. Other types of engine mounts
Smaller-scale model rockets utilize simpler engine mount designs. These use materials like cardboard, phenolic resin, or fiberglass, with associated mass implications.
Important Note: The engine mounts are integral to the rocket's structure, designed to safely contain forces and maintain trajectory during flight. While the precise mass might not be publicly available, the information above helps to understand the scope and scale of this critical component
Offline
Like button can go here
AI Overview
Detailed public information on the specific mass of the fuel plumbing within the Delta IV rocket family is limited in the provided search results. However, the available information provides insights into the fuel systems and related components, allowing for some inferences.
The Delta IV family of rockets utilized liquid hydrogen and liquid oxygen (LH2/LOX) as propellants for both its first stage (Common Booster Core - CBC) and second stage (Delta Cryogenic Second Stage - DCSS). The fuel plumbing would be a critical part of delivering these propellants from the tanks to the engines.
The search results offer information about the Delta IV's fuel systems and their components:
CBC Construction: The CBC includes isogrid aluminum barrels, spun-formed aluminum domes, machined aluminum tank skirts, and a composite centerbody. A cable tunnel carries electrical and signal lines, along with a feedline for liquid oxygen to the RS-68 engine. This indicates fuel plumbing within the structure.
DCSS Construction: The DCSS also uses isogrid aluminum ring forgings, spun-formed aluminum domes, machined aluminum tank skirts, and a composite intertank truss.
Engine Connections: The RS-68 engine on the CBC connects to the thrust structure via a quadrapod thrust frame and is enclosed in a composite conical thermal shield.
RL10B-2 Engine: The RL10B-2 engine, used in the DCSS, weighs 664 lbs. This weight likely includes internal plumbing but doesn't specify the plumbing mass.
Simplified Design: The RS-68 engine was designed for simplified construction, with a lower chamber pressure, efficiency, and a simpler nozzle than the Space Shuttle Main Engine (SSME). It has fewer parts than the SSME and a simpler nozzle. This might suggest a less complex (and potentially lighter) plumbing system for the engine, but it does not specify the mass of the entire fuel delivery system.
Although the exact mass of the fuel plumbing is unavailable, it is a key component constructed with materials like aluminum alloys and composites. The focus on reduced weight in components like the isogrid tanks suggests an effort to optimize the rocket's overall mass.
Additional points:
The Delta IV Heavy, with three Common Booster Cores, has a larger fuel plumbing system than other Delta IV variants.
In conclusion, although the exact mass of the fuel plumbing is not disclosed, it is an integral part of the Delta IV rocket family's structure and performance, designed with weight and reliability in mind.
Offline
Like button can go here
As you can see most are not forth coming with all dtails but if you know enough of the dry mass of select parts you can ball park the others.
Offline
Like button can go here