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This topic is created for our new member, HG Muller.
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Hi everyone!
Let me introduce myself:
I am a retired Dutch physicist, and have been interested in space travel since I was in highschool. I even applied for a job as astronaut once (and was swiftly rejected...), because I fitted the profile for flying as a mission scientist in the shuttle spacelab. (But that was before I learned these things could explode!) I worked until 2008 as a researcher in the government-funded laboratory for Atomic and Molecular Physics, studying interaction of atoms with super-intense and ultra-fast light pulses, after which I took an early retirement to spend more time on my (other) hobbies. Since then I spent most of my time developing software for playing various forms of chess, and genealogical research.
I noticed that youtube is recently flooded by AI slop claiming that return trips to Mars would be impossible, largely based on flawed arguments, in particular w.r.t. required velocities. This annoyed me, so I was looking for more serious discussions on the subject. An inetrnet search on the terms "mars forum" then brought me to this place. I have some ideas for lowering the effort required for space exploration, and would like to share those with knowledgeable persons, hence I applied for registeration here.
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Welcome to the forums, HG Muller!
I think you have encountered Tahanson43206, and there are a few others of us on these forums. I am an old retired defense industry development engineer, and a retired teacher. I got started in the slide rule days, and was interested in spaceflight long bore anybody went up there. Never actually worked for NASA, though. When I was young, the X-15 replaced the X-1 and the D-558-2, just about the same time as NASA was founded from the old NACA. I well remember the hoopla when Sputnik first went up.
Most of my industrial work was in air-launched missiles and the countermeasures that defeat them. But you might remember the LTV "Scout" satellite launcher. It was a 4-stage solid that could put small (by today's standards) satellites into orbit. I got to work on advanced configurations for it at LTV one summer as a graduate student. About that same time, I learned the old Allen & Eggers simplified by-hand analysis for entry dynamics and heating. Did my MS in a hypersonic wind tunnel working on Shuttle nose shapes before that design "gelled". What we grad students found, about the AOA limits on shuttle entry, was later verified at the AEDC facility in Tennessee.
Anyhow, welcome!
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For HG Muller re post in Engineering tools forum ....
Thank you for your many interesting and helpful posts!
In general, the members of this forum ignore the topic and write whatever they feel like.
The Tools forum was created in a Category that is hidden from public view.
GW Johnson created a topic about a specific set of tools. You have the opportunity to open the tool box and see if you can understand how to use the set. No one else appears to have the time, or perhaps the interest, or perhaps even the ability to use the tools GW Johnson has created.
Your post is more or less a free form essay on the general theme of orbits and interaction with an atmosphere.
Please go back and see if you can understand the tool set, and perhaps even use it effectively.
I am confident GW Johnson would respond favorably to feedback you might be able to provide on the accuracy of the tool set or the ease of use for persons with varying backgrounds.
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I posted it in the tools topic because GW's announcement of the posting there mentioned that his tools did not calculate the flight path through the atmosphere, but expected it as an input that the user would have to supply (in the form of an angle). So it would be of interest to potential users of the tool to know how to calculate that angle, and what a typical value would be.
I will have a look at the tools. We have Excell only on my wife's computer, though, and my only remaining laptop that could run Linux (in a virtual machine) has a broken keyboard. Things degrade fast when you have no time to remedy them... :-(
Last edited by HG Muller (2026-10-20 11:16:16)
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For HG Muller ... there is a way to post equations in this forum...
We offer an image server that can hold images up to 256 kb. Here are a couple of many examples:
It helps to explain mathematical thinking if the correct display format is available.
This post shows an image created by GW Johnson:
https://newmars.com/forums/viewtopic.ph … 51#p240051
and this post shows an image created by ChatGPT under my direction.
https://newmars.com/forums/viewtopic.ph … 74#p240674
There are many image servers and you may well have your own preferred service.
If you would like to use ours I'd be happy to create an account for you.
Images need to be entered as Left Bracket img Right Bracket (URL of image) Left Bracket /img Right Bracket]
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For HG Muller ...
GMAT is a software sponsored by NASA and available to the public.
I investigated it and learned that it depends upon MATLAB.
I hesitated to pay for a license for MATLAB because at time there was no one in the forum able and willing to help me figure out how to use it.
You are certainly capable. However, your time may well be limited.
You also may have to update your computer hardware, and that may be low priority as you work on your "new" home.
Never-the-less, the offer is "out there"
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I never used MATLAB. When I want to calculate something I just write a program in a simple programming language, usually C. In the past years I also got some experience with JavaScript, for web applications.
I am usually not to keen on using software written by others anyway; it often takes me more time to learn how to use it than it would have taken me to write something myself that does the one thing I want to do. And very often it doesn't do exactly what you want to do anyway. And I hate to use software that I cannot change.
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Welcome to the forum Dr Muller. You clearly have a lot of technical knowledge and you have brought a lot of discussions back to life. I look forward to working with you.
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For HG Muller!
It appears that your idea of replacing MATLAB with Python was actually done by volunteers supporting the open source GMAT package.
I learned today that the MATLAB structure has been duplicated in an open source equivalent called "Octave" but (more importantly) someone has apparently duplicated all the MATLAB functions in Python.
If you are curious, here is a post that summarizes the news!
https://newmars.com/forums/viewtopic.ph … 86#p242286
So! Congratulations on having anticipated how things would go!
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