Google Meet Collaboration - Meetings Plus Followup Discussion

tahanson43206 · 2025-11-23 17:49:06

System check went well as UTC 23:48 ... The waiting room is due to open a bit before 1:00 UTC.

7 PM Houston, 8 PM New Hampshire, mid-Morning Australia

Waiting room is open 1:00:00

(th)

tahanson43206 · 2025-11-30 09:26:55

Today is Google Meeting day for NewMars.

All members (and guests) are welcome, if you can work the time into your schedule.

As a reminder, we are willing to open the meeting at an earlier time that might work better for our European members.

The existing time (midnight or 1 UTC) was convenient for the folks living in Texas and New Hampshire.

No time is ideal for everyone.

The existing time would (hopefully) work for a member living in Australia. The time there would be mid-morning ( I understand ).

That would be right in the middle of a workday morning, of course.

Special meetings can be arranged at almost any time that the participants and host(s) can agree upon.

Such a special meeting is planned for 1 PM Houston time today. kbd512 (our webmaster) and I are planning a work session to see if we can bring the NewMars image server up on the Mars Society system. The test system on the Azure account has proven itself to be reliable, and usable by NewMars members.

The regular meeting is scheduled for 1:00 UTC, 7 PM Houston, 8 PM New Hampshire, and mid-Morning New Hampshire.

I hope to have a run of extendedMerlin from time zero to 3 seconds to show to attendees. The run is in progress now, standing at 2.49 seconds.

This run will (if all went well) show operation of the new volume heating system from the start of a run for a full 3 seconds. For the first 2 seconds we slowly increase the flow of hydrogen into the heating tube, until we reach the prescribed rate of 2 kg/s. We then have a full second of operation at full flow with 40 MW of thermal energy added uniformly to the 24,000 cells in the intake, exactly as the physical heating system would supply thermal energy to the incoming hydrogen in deep space. Because of the ridiculous large nozzle throat (25 cm) we only see about a bar of pressure in the intake, but we'll see that improve when we reduce the size of the throat to better match GW Johnson's recommendation of (about) 3 cm for hydrogen.

I note that kbd512 has found documents from NASA and from other sources showing much smaller diameter throats. The Merlin engine was designed for massive flows of hydrocarbon fuel and liquid oxygen. Hydrogen would (apparently) perform better with a much smaller throat. Work on a small throat for the OpenFOAM is scheduled for next week. ChatGPT5 offers a minimum of 3 options for reducing throat size. Two are temporary methods that are implemented with adjustments to the control dictionaries. The "permanent" solution involves changing the mesh. That option is attractive because we would be building new mesh on the existing Merlin engine mesh. That seems easier to me than trying to remove cells from the mesh, as would be the case if we were trying to increase throat size. I am looking forward to trying the three options and learning about the strengths and weakness of each.

The fourth option is to create an entirely new mesh for the hydrogen engine and extended intake. While that is certainly possible, it is a ** lot ** of work, and I'm hoping one of the easier alternatives will meet our requirements. The temporary solutions involve creating a mathematical "washer" shape to be inserted into the existing mesh at run time. The resulting opening will (most likely) create turbulence because the opening will not be rounded smoothly like the existing mesh, but it should certainly build up pressure in the intake, and allow more time for hydrogen to warm up before it reaches the throat and departs for deep space. If one of the temporary solutions shows significant gains (as seems likely) we can embark upon finding a permanent solution.

Update: For those who might be curious, the CFD model should be able to compute the behavior of hydrogen in the intake if we set the throat diameter too small. The pressure should rise beyond the bursting point of any known material. The CFD model would (presumably) not break, but past the bursting point of known materials, the results are not particularly useful.

(th)

GW Johnson · 2025-11-30 11:57:43

It's not the identity of hydrogen that makes the big difference. It is merely the interplay of mass flow rate, throat area, the effective c*-velocity of the chamber conditions, and the resulting chamber pressure. Hydrogen vs something else merely changes the c*-velocity, by several-to-many percent, but not by really large factors. The temperature is higher but the molecular weight is lower. Those effects upon c* are in the same direction, though (see below).

All species, no matter how they are heated, must obey the nozzle flow rate equation: wnoz = Pt CD At gc / c* where CD is the discharge efficiency of that choked throat: effective A / geometric A, and is usually rather close to, but never exactly equal to, 1.

As for c*, there is an equation for it, too: c* = square root of (gc R Tc GF / gamma), where GF is a function of gamma, but it is always pretty close to 2.9 in numerical value. The square root reduces the effects of large changes in Tc. The molecular weight shows up in the gas constant R, which is the molar universal value divided by the molecular weight. That is actually the bigger change with non-combustion heated hydrogen, simply because the molecular weight is greatly lower than that of most other species, and the effect is only reduced some by the square root.

GW

PS: the GF is (gamma + 1)/2 raised to an exponent that is (gamma + 1)/(gamma - 1). We have modeled hydrogen's gamma as 1.4 from cryogenic to 1000 K, decreasing linearly to 1.286 as the temperature increases to 3000 K, with molecular weight constant at 2.016 throughout that temperature interval. Beyond 3000 K, dissociation changes all those numbers. It is not molecular hydrogen anymore.

Last edited by GW Johnson (2025-11-30 12:04:45)

tahanson43206 · 2025-11-30 18:59:36

Google Meeting for Sunday the last day of November, 2025, is under way

00:59:22

Open for business....

Post meeting notes:

This was another ** very ** productive meeting ...

GW Johnson and kbd512 are both set up on the new image server.

All NewMars members are welcome to register with the new images server. I left registration open for now. I'll close registration when the first spammer finds the site and breaks in. In the mean time registrations are welcome from NewMars members.

***
Work on the OpenFOAM study of the Optical Plane rocket engine will resume next week with three different ways of creating the effect of a smaller throat. One method involves setting a porous "wall" in front of the throat. The amount of porosity will (I gather) simulate the effect of having a smaller throat.

The next method is to mathematically create a ring or washer shaped structure dynamically at run time. This is (apparently) a bit more difficult, but it will allow us to see what an opening of 3 centimeters will "look" like to the hydrogen gas we are pumping through the system.

The third method is more challenging, and it is where I want to end up. This involves creating a mesh shaped like the ideal engine that GW Johnson has prescribed, and blending or merging it into the existing mesh. I am attracted to this option because we are shrinking the throat, and the new mesh will (if all goes well) blend seamlessly into the existing Merlin engine mesh, so that the original Merlin Mesh will be inside the new mesh. I'm told (by ChatGPT5) that this procedure will result in a model that looks to the gas like the engine GW Johnson would like to see for this application.

The distinct advantage of this approach is that all the rest of the mesh is retained and I don't have to worry about it.

This whole process is likely to take to the end of the year.

(th)

tahanson43206 · 2025-12-07 07:44:44

Today is Google Meeting day for NewMars.

The waiting room will open shortly before 1 AM UTC, 7 PM Houston, 8 PM New Hampshire, and mid-morning Australia time.

We have a report on the outcome of GW Johnson's requested special run of the extendedMerlin model. It shows 5 force-tons of thrust given 20 kg/s of intake flow, despite heating the hydrogen to only 300 Kelvin which is about 80 degrees Fahrenheit. This result is obtained while keeping the 25 centimeter throat that is associated with the original Merlin engine design. ISP is calculated to be 250.

A question I am hoping we will discuss is how the momentum transferred to the ship compares, if we feed propellant at 20 kg/s for one second giving 5 tons-force, or if we feed 2 kg/s for ten seconds giving 1/2 ton-force. It seems to me the momentum imparted would be the same but am looking forward to learning what would actually happen.

In previous discussion we have considered reducing the throat size to 3 centimeters, and I presume that would improve the performance of the 2 kg/s flow. ISP should improve, but that remains to be seen.

We have a suggested location for craters for Caliban, GW Johnson and Void to use as building sites. The site is calculated to be 54 kilometers from the Viking 1 landing site, which may be seen at trek.nasa.gov/Mars.

Calliban has proposed a 200 meter diameter open interior dome with LED lighting inside to provide Earth-like illumination,

GW has proposed buildings with traditional supporting columns in the interior, with windows to the outside.

Void has shown images of solar energy collectors arranged inside a crater.

Other reports are highly likely.

If we are lucky we may get to take a deep dive into some interesting topic with kbd512 as our Internet guide.

Thanks again to kbd512 for providing the new NewMars Image Server. The server is working well. New images are being added every day, and old ones are being ported from the Azure test server as time permits.

All NewMars members are eligible to store original images on the image server. Registration for existing members is open at present.

(th)

tahanson43206 · 2025-12-07 17:31:52

Systems check at 23:29 UTC went well ... we are on track to open the waiting room at just before 1 AM UTC.

Houston time will be 7 PM, New Hampshire time will be 8 PM, and if we were to have someone from the West Coast, the time there would be 6 PM.

If anyone in Australia were to decide to join the meeting, it would be mid-morning

UTC 59:59 the waiting room is open.

This was another interesting and productive meeting. The decision I was looking for was which of three possible approaches for the next phase of development of the extendedMerlin model should be given priority. It amounted to a coin toss, so I'll proceed with the washer approach instead of the porous filter one.

As a reminder for anyone might be intererested, the Merlin engine model we are using came from the "factory" with an intake diameter of 25 centimeters. We've been running hydrogen with that diameter, at flow rates of 2 kg/s and 20 kg/s. Last week i ran a series over 0 to 7 seconds for the 20 kg/s case. We got a thrust of nearly 5 tons-force.

That compares to .5 tons-force for 2 kg/s which was produced by our first successful run with the new even heating method.

Next week, I'll attempt to configure the model to simulate a 3 centimeter throat. This particular approach introduces an "object" shaped like a flat washer into the throat. The result will create turbulence, because the flow at the opening will not be smooth as would be the case with a properly designed throat. However, we ** should see increased temperature in the intake, and the ISP should improve from the present value of 250.

We did not get to the mass of the optical collection devices, so I'll have to add that back to the agenda for next week. I am now starting to to think about how the Optical Plane vessel might be constructed in the Real Universe, now that we have evidence kbd512's discovery of optical capture devices will actually work.

Update: During the week just ended, Void posted a link to a video about the inventor of the Merlin Engine. There is a Wikipedia page about this gent. He was the first employee hired by Elon Musk for the new company SpaceX.

(th)

tahanson43206 · Yesterday 08:12:29

Today is Google Meeting day for NewMars ...

Hopefully our regular attendees will be able to schedule the time to join.

All other NewMars members are welcome to attend...

We have a number of interesting topics to consider, and new ones come up every meeting.

Deep dives into the Internet are a feature provided by kbd512

Possible items for discussion:

1) A remote controlled camera for Zoom meetings.

I will try to have this camera ready for demonstration this evening. The camera only works with Zoom, because the Zoom app has been modified to allow it's use. I am hoping the camera will facilitate remote presence at special events which I cannot attend in person.

2) We have a decision to make about how to proceed with the extendedMerlin model for the Optical Plane vessel.

As things stand, we appear to have achieved an ISP of 250, which is decent but not what is thought to be possible.

The existing model has been tested with a flow rate of 2 kg/s and one of 20 kg/s.

The model is stable with both, and it delivered the thrust predicted by GW Johnson for the greater mass flow.

The choice of the next test series is between a porous filter and a washer shaped mathematical structure.

kbd512 voted in favor of the washer shape last meeting, and we have an opportunity for GW Johnson to weigh in this week.

3) Calliban's Dome is a possible subject for discussion. We have a Crater selected on Mars, and I am hoping that we (NewMars) can begin working on developing a plan for exploring the crater with one or more probes, and then organizing a fleet of robot equipment to build the dome and the related infrastructure. In recent days we've been discussing how to illuminate the dome and how to manage the air.

As usual, we will plan to open the waiting room at 1:00 UTC.

That time is 7 PM Houston, 8 PM New Hampshire and mid-Morning in Australia.

(th)

tahanson43206 · Yesterday 18:59:19

The waiting room is open...

This was another successful meeting...

Topics included Vandenberg Space Base, prospects for SpaceX there, and discussion of SpaceX receiving approval to build a launch facility for Starship at Cape Canaveral.

Topics included Calliban's dome, the forces at work in the building walls, and procedures for managing the air and various fluids.

The decision was made to proceed with the "washer" option for the OpenFOAM investigation of extendedMerlin for Optical Plane.

A variety of other topics came up briefly.

(th)

RobertDyck · Yesterday 21:47:16

In 1999, I did propose the Mars Roadrunner project. At that time the idea was a ride to space as a get-away special on the Shuttle. 150 pounds total, fit into an oil barrel shape container. I spoke to the individual at NASA in charge of small Shuttle projects. He said $8,000 US funds for any US educational institution, or $27,000 for anyone else. However, he apologized saying that's not you go up and come down. It was $2 million if you just let got of the Shuttle and stay in orbit. But he said if a NASA agency (as he called it, cost center to be picky) sponsored US, we get a free ride. And he with our connections (Mars Society) we would have no trouble getting that. At the time we had a couple senior research fellows from the Ames Research Center on the board of directors. (200 pounds, or 150 pounds plus ejection mechanism)

I got detailed technical information on the NSTAR ion engine used for Deep Space One. I spoke with the lead engineer at the Glenn Resear Center who developed the engine. As he put it, he sent everything allowed outside the US. Everything short of the blueprints. So spiral out of LEO, head to the Moon. Use the Moon for gravity assist (0.5 km/s addition delta-V) then slow route to Mars. Expect 2 years to Mars. In space performance report says 3,000 second Isp. Xenon gas propellant.

At that time we had a Mars Society member from Australia who just graduated with his PhD in aerospace engineering specializing in aeroshells. He offered to design the aeoshell including heat shield. Unfortunately he's no longer available. He now works for SpaceX as their primary Mars guy.

We were going to deploy a weather balloon using Dr Zubin's design. He just tested a prototype, paid by NASA, deployed in Earth's upper atmosphere where temperature and pressure are the same as Mars. They used a weather balloon to lift it, then deployed the Mars balloon.

At the time I worked for a company that specialized in developing software for embedded systems using the QNX operating system. That was used for the vision system on CanadArm, both for Shuttle and ISS.

We were going to use a Mars UHF antenna to transmit data to Mars orbiters: MGS, Mars Odyssey, MRO, Mars Express. We would need NASA's permission not use their obiter(s) as a communication relay, and the Deep Space Network to communicate with it. We would ESA's permission if we were to use Mars Express. However, a later project would build a dish array using used large satellite TV dishes as a Deep Space Station not communicate with an orbiter passed it's extended mission. We never did find the dishes, but in 2002 when I spoke to a woman at a Canadian Space Agency workshop, she liked the idea. She (through her company, Thoth Technology Inc.) gained control of a disused 50-foot radio astronomy dish in Canada, in a radio quiet zone in Algonquin Park. She's working with a University. One goal is to use that as a Deep Space Station for Mars missions.

RobertDyck · Yesterday 22:07:56

When NASA was preparing to launch MRO, they didn't behave room on the Deep Space Network for all the Mars missions. Something nhad to be sacrificed. Then someone "accidentally" sent a bad command that deactivated MGS. Grrr! I don't believe it was an accident. I wish Caroline's station in Algonquin Park was ready, so NASA didn't have to kill MGS. I wanted to use MGS as a communication relay satellite.

Her company's website:ThothX
(Why is her "significant other" now listed as CEO, and she's not listed on the leadership team at all?)

RobertDyck · Yesterday 22:43:41

My point is if you want to get serious about exploring the craterz sending a probe is possible. It will cost. SpaceX has a SmallSat Rideshare program. Cost estimate for 100Kg to Sun Synchronous Orbit $650,000

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