GW Johnson Postings and @Exrocketman1 YouTube videos

Void · 2023-01-25 19:48:45

I hope your healing goes well.

Done.

SpaceNut · 2023-01-25 20:29:02

That is good news GW as the longer they were to wait the more chance that they would have had to do an alignment surgery. Best wishes for a speedy recovery.

tahanson43206 · 2023-01-30 15:56:50

This is an update on developments with the updated Space Tug proposal, which was completed just before Dr. Johnson's encounter with the immutable Laws of Physics.

I am pleased to report that despite being slowed down, GW is resuming a series of steps that will (hopefully) lead to mailing of the proposal and supporting materials.

I am hoping we can have at least one letter in the mail by the end of the first week in February.

I'll be assisting in very minor ways, as requested.

The specific services I am hoping to provide involve preparing physical documents for mailing, since mailing locally is no longer convenient.

The detail of how to pack a signature with the cover letter is resolved. I've asked Dr. Johnson to send me the cover letter (with signature) in an ordinary business envelope, which (I am hoping) the USPS driver will pick up from the mail box at the end of the driveway. I'll print the pdf of the Proposal at a commercial printer, to insure full color for the images and graphs.

Update 2023/01/31 ... things are progressing ... plans are in development to attempt a mailing by Noon this coming Saturday, February 4th.

(th)

tahanson43206 · 2023-02-03 13:39:23

This is an update on developments with the updated Space Tug proposal, which was completed just before Dr. Johnson's encounter with the immutable Laws of Physics.

A commercial printer accepted PDF files of paper and cover letter provided by Dr. Johnson, and the results were packaged in one of the sturdy USPS mailers, along with a cover letter.

The package will be turned over to a nearby USPS office shortly.

***
Update after mailing ... the package with two copies of GW Johnson's latest Space Tug proposal is on it's way! We heard nothing from the earlier similar mailings, so a response from this one is unlikely.

(th)

tahanson43206 · 2023-02-04 11:14:38

Update on Space Tug proposal

Tracking Number: <entered into system 2023/02/04>
Copy Add to Informed Delivery
Expected Delivery by
MONDAY
6
February
2023
by
9:00pm
Your package is moving within the USPS network and is on track to be delivered by the expected delivery date. As of February 4, 2023 at 9:06 am, it is currently in transit to the next facility.
Get More Out of USPS Tracking:
USPS Tracking Plus®
Delivered
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Preparing for Delivery
Moving Through Network
In Transit, Arriving On Time
February 4, 2023, 9:06 am
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See All Tracking History
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Product Information

Reminder ... it is normal for unsolicited proposals NOT to be acknowledged in any way.

Nothing is expected in this case either.

(th)

tahanson43206 · 2023-02-07 15:05:43

For all...

The topic is intended to be a repository for work done by GW Johnson....

It was not intended to be a Chat topic...

The opening post reads:

This new topic is opened to (try to) provide a convenient access point for work of GW Johnson that resides outside the NewMars forum database.
That said, this topic is ** also ** an excellent place for NewMars members to post comments about any of the many posts already in the database.

Please move interpersonal combat to other topics.

(th)

GW Johnson · 2023-02-08 12:52:21

I recently posted a nozzle article on "exrocketman" comparing an aerospike nozzle to conventional bells for ascent from the surface to orbit. These used sonic-only gas generators firing tangentially onto the spike surface. I had to reduce both chamber pressure and design altitude in order not to lose everything to extreme lateral expansion flying past the lower stratosphere. I knew how to optimize conventional bells, but did not know how to optimize aerospikes.

A couple of days later, I added an update that looked at a short conventional expansion bell on the gas generators, followed by free expansion to ambient upon the spike. This provided sufficient limitation on the extreme lateral plume fan-out angles that I was able to raise design altitude and chamber pressure. That seems to have recovered at least most of the potential performance of an optimized aerospike design. The issue of compression shocking upon the aerospike surface as it turns the gas generator plumes axial is something only finite-element method-of-characteristics (MOC) modeling can address, and then only with MOC models sophisticated enough to model shock waves.

At any rate, the article with that update added is something I sent Tom Hanson as a pdf file. He is going to post it here for me. The basic updated result says that an aerospike can equal or exceed a compromise-vacuum bell's performance from the surface to the mid or even upper stratosphere, but then falls below the performance of even a sea level bell as you fly from there on out into vacuum. They are simply NOT good vacuum engines, not at all.

Per request of GW Johnson, here is a link to the Aerospike pdf:
https://www.dropbox.com/s/0nmcchac07sz1 … e.pdf?dl=0

GW

tahanson43206 · 2023-02-14 11:00:54

This post is intended to hold a link to work done by Dr. Johnson regarding Towed Targets and Towed Decoys...

https://www.dropbox.com/s/77yqoykkbl5r6 … D.pdf?dl=0

SearchTerm:Target Towed Targets for pilot training
SearchTerm:Decoy Towed Decoy for in-flight defense

(th)

tahanson43206 · 2023-02-14 11:24:51

This post is intended to hold a link to an article about the Chinese Spy balloon, published recently in the exRocketman Blog.

https://www.dropbox.com/s/u5m6mmhw5px04 … n.pdf?dl=0

SearchTerm:Balloon Chinese Spy

(th)

GW Johnson · 2023-02-20 10:01:24

As near as I can tell, the links Tahanson43206 created for these things all work just fine.

GW

GW Johnson · 2023-02-20 11:06:59

The forum software wn't log out.

GW Johnson · 2023-02-20 13:49:56

Now it logs in and out OK. Sometimes weird problems just happen, I guess.

GW

tahanson43206 · 2023-02-21 14:12:40

This post is intended to provide access to recent work by GW Johnson regarding orbit changes using traditional techniques.

The explanations to go with the files are to be added soon. after I get the links set up.

1 of 5
https://www.dropbox.com/s/2zw198ujfzwpb … h.png?dl=0

2 of 5
https://www.dropbox.com/s/pu2tpekn9666g … g.png?dl=0

3 of 5
https://www.dropbox.com/s/hddnza9n2dy0z … r.png?dl=0

4 of 5
https://www.dropbox.com/s/t3q6to7x7l10i … a.png?dl=0

5 of 5
https://www.dropbox.com/s/4k4yjawrn8xez … g.png?dl=0

I invite everyone to call up these files while we wait for text to go with them.

Update 2023/02/22 ... the file at the link below is a visual aid showing orbits between Earth and GEO
https://www.dropbox.com/s/m1734w6oi6kgn … s.png?dl=0

Update 2023/02/24 GW Johnson provided text to go with the links above, but FluxBB or Apache refuses to let me post them. I'll try to get them up soon.

(th)

tahanson43206 · 2023-02-25 07:30:39

Separate post for link 1 of 5

tahanson43206 wrote:

This post is intended to provide access to recent work by GW Johnson regarding orbit changes using traditional techniques.
The explanations to go with the files are to be added soon. after I get the links set up.
1 of 5
https://www.dropbox.com/s/2zw198ujfzwpb … h.png?dl=0
I invite everyone to call up these files while we wait for text to go with them.
(th)

Following is text provided by GW Johnson to go with the link above:

The first in the list of five is 20230219 geosynch.png, which is an image of a spreadsheet worksheet that I created just to do very simple 2-body elliptic orbit problems, with the closed-form equations given in fundamentals of orbital mechanics textbooks. User inputs are highlighted yellow, significant outputs are highlighted blue.
The default inputs are for the Earth: its name, mass in kg, and its equatorial and average radii in km. There are notes advising when to use which radius. Under “desired orbit data there are user inputs for min and max altitude (km) above the surface, and an input for which of the two radii is appropriate. The altitudes are converted to min and max radii using the input value of R.
To the right, the worksheet figures surface escape and circular orbit speeds (km/s) using the average radius. These are figured from Vesc2 = 2 GM/R and Vcirc2 = GM/R, using meters and meters/sec in the equation, m converted from km, and m/s converted to km/s. The notes below this explain how these values are rescaled to altitudes above the surface.
The rest is completely automatic. The sum of the min and max orbit radii is equal to the major axis length. Half that is the semi-major length a reported in the first block. The difference in radii divided by their sum is the eccentricity of the ellipse. That is highlighted and reported in the next block. The distance from ellipse center to either focus is c = a*e. The semi-minor axis length is figured from b2 = a2 – c2, and is useful mainly for plotting the ellipse.
Under the group labeled “at perigee”, the speed at the perigee (min R) point is figured using the indicated equation. The equation uses m and m/s. Units must be converted from km to m, snd from m/s to km/s. The circular and escape speeds are figured and reported at this value of R. The two delta-vees (dV) are Vper – Vcirc and Vesc – Vper. These may be computed as scalar subtractions because the vectors are parallel.
Under the group labeled “at apogee”, the speed at the apogee point (max R) is figured using the indicated equation again. Once again, the circular and escape speeds are computed and reported at this value of R. The two dV’s are Vcirc – Vapo and Vesc – Vapo. These may be computed as scalar subtractions because the vectors are parallel.
Under “period” there are 4 entries. The first is the round trip period around the ellipse in seconds, figured from the indicated equation. It uses m, kg, and s. The km have to be converted to m to use this. The second entry is the period in minutes = sec/60. The third is the period in hours = minutes/60. The fourth is the period in days = hours/24.
The first thing I did with it was determine the altitudes of a geosynchronous orbit by iterative altitude inputs. Those data are listed in the image.
The next thing I did was explore the dV’s for a transfer ellipse from 300 km altitude to geosynchronous altitude. Those data are listed in the image: the dV from 300 km circular onto the transfer ellipse, and the dV to circularize at geosynchronous altitude. As long as the thrust is impulsive, these dV values need not be factored up to obtain mass ratio-effective values.
The third and last thing I did was explore the dV’s for a surface-grazing transfer ellipse to geosynchronous altitude. The Vper is the launch dV onto this trajectory. This would be appropriate for a direct surface launch onto the transfer ellipse, but is unfactored for gravity and drag losses. The dV for circularizing at geosynchronous orbit needs no factoring, as long as that propulsion is impulsive.

(th)

tahanson43206 · 2023-02-25 07:30:59

Separate post for link 2 of 5

tahanson43206 wrote:

This post is intended to provide access to recent work by GW Johnson regarding orbit changes using traditional techniques.
The explanations to go with the files are to be added soon. after I get the links set up.
2 of 5
https://www.dropbox.com/s/pu2tpekn9666g … g.png?dl=0
(th)

Here is text to explain the file at link #2:

The second in the list of five is 20230220 geosynch.png, which is an image of a spreadsheet worksheet that I created just to do very simple rocket equation vehicle sizing, but for a tug vehicle that burns its propellant load in two different weight statements.
The tug first makes a main burn plus a couple of rendezvous burns unladen (not pushing anything but itself), then it makes a main burn plus a couple of rendezvous burns laden (pushing a significant payload plus itself). This is a tug based at a station in geosynchronous orbit that goes to the apogee of a transfer orbit and rendezvouses with a payload sent up on that transfer, then brings that payload with itself back to geosynchronous and rendezvouses with its basing station.
A nominal half of that payload mass is considered to be source materials (water) for making propellants at the basing station in geosynchronous orbit to power the tug. Hydrogen-oxygen propulsion is presumed for the tug.
User inputs are generally highlighted yellow, and significant outputs highlighted blue or green. The green ones apply to iterations and feasibility checks.
The tug propulsion is addressed in the top left group. There are inputs for specific impulse (sec), engine thrust/weight, the ratio of propellant to propellant-plus-inerts for the propellant tankage, the number of the engines installed, the min and max gee levels to be allowed, and the mass (metric tons) of the robot guidance and control system, including its power supply. Computed values are given for effective exhaust velocity Vex = Isp * 9.80667/1000, the propellant tankage inert-to-propellant ratio = (1 – R)/R, and the mass of the installed engines at the installed thrust levels.
Under “vehicle” (top center group), there is an input for the mass (metric tons) of the payload the tug is to retrieve, and an output indicating the propellant mass (metric tons) aboard the tug.
Top right group contains the burn requirements analysis for the unladen and laden phases of the mission. Under dV’s for unladen and laden, the values of “burn” and “rendez” should be highlighted yellow, as these are inputs. I just failed to highlight them. The “burn” values are dV for getting to and from the geosynchronous orbit onto and off of the transfer orbit. These were figured with the first of five items here. The “rendez” values are just best guesses for rendezvous dV budgets. Mass ratios MR = exp(dV/Vex) are shown. The blue highlighted items are the summed unladen and laden dV’s, and the corresponding MR values.
The next group goes all the way across, and comprises the rocket equation burn analyses, unladen first, plus the effects of the other constraining items. The propellant masses highlighted yellow, are user inputs that must be iterated to convergence, as indicated by the green-highlighted necessary mass ratio “need MR” error column. The d-inert items are the tank inerts associated with those propellant masses, and their sum is the blue-highlighted tank inert value just below. To that must be added the engine inert and the guidance-and-control inert masses, for the total vehicle inert highlighted blue.
Here is the key to the difference in weight statements for the two burn calculations: the tug pushes no payload item in the unladen burn, but must carry the propellant for the laden burn as its “payload”. For the laden burn, payload is the mass input for the payload item, and there is no other propellant to be carried as “payload”. From that point, for each burn calculation, burnout mass in metric tons “bo mt” is inert plus “payload” masses, ignition mass in metric tons “ign mt” is burnout mass plus propellant mass, and the resulting mass ratio “result MR” is ignition mass divided by burnout mass. The error in mass ratio “err MR” is “need MR minus “result MR”. This needs to be zeroed as closely as possible, while still remaining very slightly negative, as marked. That is the propellant mass iteration.
From that point, one must address the thrust levels and number of engines in terms of min and max vehicle gees, to be followed by re-iterating propellants, then reassessing thrusts, and reiterating propellants, back-and-forth, until things are “close enough”. “F mtf ming” is the necessary thrust level totalled for all engines, measured in metric tons-force, to achieve vehicle acceleration at input min gee levels. The laden burn is larger and sizes this value.
The next column is the yellow-highlighted user-input number of engines active during the unladen and laden burns. The laden burn sets the max number of engines, and this or less can be be the number of engines active during the unladen burn. You revise these choices to stay within the min to max input gee levels.
Just below “F mtf ming” are two blue-highlighted outputs. One is the thrust per engine, metric tons-force, “F/eng mtf”. It is sized from the laden burn thrust value and user-input number of engines for that burn. The other is weight per engine, metric tons of mass “W/eng mt”, which is the per engine thrust divided by the user-input thrust/weight ratio.
This weight per engine multiplied by the number of installed engines is the vehicle inert mass contribution coming from the sized engine installation. Unfortunately, this number used directly in the earlier vehicle inert mass estimate creates a circular logic problem. So at this point, the usder reads the weight per engine result, and must re-input that in the indicated yellow-highlighted input location adjacent, labeled “W/eng”. That clears the circular logic problem. This must be done each time the calculation of thrust is re-iterated.
The rest of the calculation uses the converged propellant and engine installation numbers to estimate thrust in metric tons-force “F mtf” for each burn, and the corresponding vehicle accelerations. Min gee is at the ignition mass for the burn, and max gee is at the burnout mass for each burn. It is at this p4oint that the number of engines active for the unladen burn might need to be adjusted to meet min gee requirements, although that was not done in the example. The max gee limit is the more serious limitation, measured by the green-highlighted max gee margin “mx g marg”, computed as max gees found minus the max gee limit that was input. This margins needs to be negative, as marked.
Once everything has been satisfactorily converged, one can trust the three outputs below this burn calculations block. To the left is a set of three tug vehicle weight statements, overall, for the unladen burn, and for the laden burn. These include mass ratios and burn dV estimates (green highlighted) for comparison to the input burn dV requirements (repeated adjacent for convenience).
The other 2 blocks are an engine specification and a payload results analysis dealing with the question of whether some fraction of the retrieved payload could be adequate to fuel the next tug trip. The engine spec gives the max thrust specific impulse that must be achieved (or exceeded) by the selected or developed engine, and that max thrust level as values of metric tons-force, kilo-Newtons, and pounds-force. These are per-engine, and correspond to the number of engines shown. These were computed without any throttling back, as indicated.
The payload analysis uses the input payload mass, the calculated propellant mass in the tug that is required to retrieve that payload to the geosynch station (where the tug is based), and a user-input fraction (highlighted yellow) of that payload that is water which is to be processed into liquid hydrogen and liquid oxygen for tug propellants for the next trip. The notion explored here is finding the ratio of propellant source mass retrieved to the propellant mass required to retrieve it. That determines how many trips must be made to retrieve the source mass for one such retrieval trip. In this example case that number is just over 3. For this to be a self-fueling operation, that trip number needs to be no more than 1. Even if the entire payload were ice, we would not achieve a trip number ratio at or under 1!

(th)

tahanson43206 · 2023-02-25 07:31:11

Separate post for link 3 of 5

tahanson43206 wrote:

This post is intended to provide access to recent work by GW Johnson regarding orbit changes using traditional techniques.
The explanations to go with the files are to be added soon. after I get the links set up.
3 of 5
https://www.dropbox.com/s/hddnza9n2dy0z … r.png?dl=0
I invite everyone to call up these files while we wait for text to go with them.
(th)

Here is text provided by GW Johnson to explain the file at Link #3:

The third in the list of five is 20230220 nontangent transfer.png, which is a plot of trajectories that I made with the data-plotting capability of the Excel spreadsheet software. This one is for a surface-grazing transfer ellipse with an apogee far beyond the geosynchronous distance. The apogee distance I picked was arbitrarily large, and could be iterated so that the transfer velocity at the geosynch crossing would equal geosynch velocity, although in this example, it is not equal, just comparable.
I took the transfer ellipse parameters “a” and “b” from the orbit analysis results, plus the equation of an ellipse with its center at the center of a coordinate system, to create a list of x-y coordinates for that ellipse to be plotted. Likewise, I wrote the equations for circles with centers at the occupied left focus of that same ellipse; one for the Earth itself, one for a low circular orbit, and one for a geosynch orbit. These also generate lists of x-y coordinate values to plot. I plotted all these figures on the same graph, and adjusted the axis scaling to make the grids approximately square.
In that way, one can easily see that the transfer ellipse crosses the geosynch circle at very nearly 90 degrees. The dV to change course from the transfer ellipse onto the geosynch circle is quite large, as indicated in the figure. Not only does the velocity magnitude need to change a little bit, but also the direction of the vector has to change a lot, which is the dominant effect.

(th)

tahanson43206 · 2023-02-25 07:31:24

Separate post for link 4 of 5

tahanson43206 wrote:

This post is intended to provide access to recent work by GW Johnson regarding orbit changes using traditional techniques.
The explanations to go with the files are to be added soon. after I get the links set up.
4 of 5
https://www.dropbox.com/s/t3q6to7x7l10i … a.png?dl=0
I invite everyone to call up these files while we wait for text to go with them.
(th)

Here is text provided by GW Johnson to explain the file at Link #4:

The fourth in the list of five is 20230220 orbit data.png, which is another plot of orbit data, made in the same way as the third item, but for a surface-grazing transfer ellipse whose apogee is at the geosynch distance, which makes the transfer ellipse tangent to the geosynch circle. At that point, the two tracks are parallel, so that dV to circularize from the surface-grazing transfer may be figured as scalar subtraction; it is 1.499 km/s.
Also shown is the very modest apogee posigrade burn necessary to raise the ellipse perigee to 300 km altitude. That is a slightly higher-energy transfer orbit, which shows in the very slightly longer period, and the slightly smaller dV to circularize at geosynch: 1.467 km/s.

(th)

tahanson43206 · 2023-02-25 07:32:14

Separate post for link 5 of 5

tahanson43206 wrote:

This post is intended to provide access to recent work by GW Johnson regarding orbit changes using traditional techniques.
The explanations to go with the files are to be added soon. after I get the links set up.
5 of 5
https://www.dropbox.com/s/4k4yjawrn8xez … g.png?dl=0
I invite everyone to call up these files while we wait for text to go with them.
(th)

GW Johnson provided this text to go with the file at Link #5:

The fifth in the list of five is 20230220 sized tug.png, which is really the assumptions and dV data used to make the burn analyses made in the second item (the image of the rocket calculation spreadsheet). The output result weight statements are not included. The dV requirements are, but bear in mind that the rendezvous dV budgets are just guesses on my part. How the weight statements are derived, and which applies to each burn, is illustrated.

(th)

tahanson43206 · 2023-02-26 20:50:27

GW Johnson provided the text below to go with the link above:

TH43206 has since posted another illustration I drew, 20230222-fitting ellipses.png, which shows Earth, geosynch circular orbit about Earth, and 3 surface-grazing transfer ellipses. One ellipse has insufficient energy to reach geosynch, and thus falls short. The second one is just tangent to geosynch orbit, where the tracks are parallel at the tangency point. That parallel geometry allows scalar subtraction to determine dV requirements.
The third has excess energy, with an apogee far beyond geosynch distance. There are two crossing points where the transfer ellipse crosses the geosynch circle. That crossing is not tangent, there is a large angle change to be made getting from one path to the other. Any dV is therefore a vector subtraction, not scalar. The symmetry of circles and ellipses also requires that the transfer ellipse velocity is the same magnitude at both crossing points.
One other crucial point needs to be made about transfer ellipses. You have to “tie down” both ends of the ellipse (or at least two points on it somewhere in some relation to its foci), in order for it to be a transfer path from one location to another. Once you tie down two points like that, there is one, and only one, ellipse that goes through those two points. That’s just high school geometry.
Do not get the wrong impression about me. I am no expert in orbital mechanics. I am familiar enough with the classic 2-body problem to do elliptical orbits with the classical equations fairly readily, and perhaps a tiny bit with parabolic and hyperbolic escape, although that has a lot less practical utility.
Real world space travel is actually a 3+ body analysis problem, for which the only solutions are finite-difference computer codes. I have no such capability. I do have a good approximation for figuring planetary transfer dV’s from linked 2-body problems, but it is only an approximation useful for estimating dV, and says nothing about speed and direction histories.
The best “how-to” stuff that I have on this topic, is an article I posted about 2 years ago on http://exrocketman.blogspot.com, titled “Fundamentals of Elliptic Orbits”, posted there 5 March 2021. It has the necessary information about how to set up and calculate elliptic orbits from periapsis and apoapsis requirements, plus information on how to select realistic factors for factoring-up theoretical dV numbers into realistic mass ratio-effective values. Central body masses and radius data can be found on the internet.

(th)

tahanson43206 · 2023-02-28 15:43:58

Today's upload of files will provide links to a presentation on the Basics of Elliptic Orbits

File 1: https://www.dropbox.com/s/sxxkwtz7s9tt2 … T.pdf?dl=0

This is a pdf format of a PowerPoint slide show

File 2: https://www.dropbox.com/s/jd95xh9v4h2ch … s.pdf?dl=0

File 2 is a text presentation with illustrations.

File 3: This is the original PowerPoint for those who prefer to run the original ...

https://www.dropbox.com/scl/fi/i49i8ppi … 0y0xsqrkw8

(th)

tahanson43206 · 2023-03-01 16:13:20

GW Johnson is working on a revised version of his current Basics of Elliptic Orbits document set.

The new version appears to include (as nearly as I can tell) a capability to adapt to an unplanned orbit, such as might occur if the third stage fails to ignite.

In the next few hoursI'll try to have the new, revised version stored in Dropbox and linked for viewing by NewMars members and by the public.

Update Wednesday evening 2023/03/01

https://www.dropbox.com/s/tqo807a0x36zv … n.pdf?dl=0

Above is Addendum to previous document

https://www.dropbox.com/s/5weq3gw2y1oah … f.pdf?dl=0

Above is a pdf version of the PowerPoint original slide show

https://www.dropbox.com/scl/fi/kv4xyd2e … yu3ylp2ww8

Above is the original slide show in PowerPoint format

https://www.dropbox.com/s/p6lrl7b3tqrb8 … q.png?dl=0

Above is a diagram showing how to determine two variables needed for planning an ellipse

Questions are welcome!

(th)

tahanson43206 · 2023-03-10 12:56:16

This is an update and follow up to Post #121

Dr. Johnson prepared an introduction to the course, to help a student to become familiar with the spreadsheet.

I have a vision developing, for how this work might become part of a set of tools that a human could carry around in a laptop, in order to be able to set up command sequences for space craft of various kinds. I foresee a day when spacecraft navigation will be as second hand for humans, as driving the family car to the grocery is today. We don't think anything of a jaunt to the market, but in fact we have mastered a massive amount of information and acquired skills of which we are unaware. It will be much the same when our descendants plan a trip between Moons or Asteroids. I expect that just as is true today, graduates of distinguished academies will command vessels in Inter-Solar-System trade routes. However, those elite graduates will be far outnumbered by ordinary folks who can navigate just fine between one Moon another or between one Asteroid and another.

The work GW Johnson put together looks (to me at least) like the foundation for a Tool Kit of facts about the Real Universe, and mathematical techniques that are the foundation of space careers today, and will surely be as we humans extend our range into the Solar System.

I would like to try to enlist members who are experienced in Elementary Education, if we have any. We have well over 1000 members whose ID's survive the Great Spammer removal, but only a tiny fraction are active these days.

If by chance there is someone with experience in Elementary Education who would be interested in helping GW Johnson to adapt and extend his Orbital Planning Toolkit down to first grade (letters and numbers) on up through PhD level, please check the Recruiting topic for procedure.

(th)

tahanson43206 · 2023-03-14 15:01:59

In this post, GW Johnson provided updates to his Introductory Exercises and an up-to-date copy of the spreadsheet for the exercises.

File 1 of 3:
https://www.dropbox.com/s/qv1yxww045yd4 … 1.pdf?dl=0

File 2 of 3:
https://www.dropbox.com/s/fa9fmf3vyiwx3 … 2.pdf?dl=0

File 3 of 3:
https://www.dropbox.com/s/hlkuvfbcts7w7 … 3.pdf?dl=0

Spreadsheet:
https://www.dropbox.com/s/gfyl7g4lpzbfg … .xlsx?dl=0

Is there anyone in the group who has time to try the exercises .... Dr. Johnson would appreciate feedback.

He is trying to adapt a college level course for a (possible) high school audience.

Updated 2023/0318 - Replaced Lesson 2 with edits.

(th)

GW Johnson · 2023-03-15 12:40:15

The files are there, although lesson 2 got listed as file 1, and vice versa. I can see the spreadsheet, but it does not actually function.

GW

tahanson43206 · 2023-03-15 13:02:06

For GW Johnson ... thanks for checking those links! I have corrected the link order, and ** think ** corrected the spreadsheet link.

OK ... The spreadsheet link still does not work. I'll go fix it.

OK ... the spreadsheet should be correct now. Dropbox sprang a surprise on me. My preference is to make files viewable, but for some reason it decided to set the spreadsheet to a different setting.

(th)

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#101 2023-01-25 19:48:45

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#102 2023-01-25 20:29:02

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#103 2023-01-30 15:56:50

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#104 2023-02-03 13:39:23

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#105 2023-02-04 11:14:38

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#106 2023-02-07 15:05:43

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#107 2023-02-08 12:52:21

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#108 2023-02-14 11:00:54

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#109 2023-02-14 11:24:51

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#110 2023-02-20 10:01:24

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#111 2023-02-20 11:06:59

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#112 2023-02-20 13:49:56

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#113 2023-02-21 14:12:40

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#114 2023-02-25 07:30:39

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#115 2023-02-25 07:30:59

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#116 2023-02-25 07:31:11

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#117 2023-02-25 07:31:24

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#118 2023-02-25 07:32:14

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#119 2023-02-26 20:50:27

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#120 2023-02-28 15:43:58

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#121 2023-03-01 16:13:20

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#122 2023-03-10 12:56:16

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#123 2023-03-14 15:01:59

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#124 2023-03-15 12:40:15

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

#125 2023-03-15 13:02:06

Re: GW Johnson Postings and @Exrocketman1 YouTube videos

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