Sunday, September 15, 2019

Rover Update

The front wheels are on! I need to get all the wheels on and locked in the straight-ahead position because I will be using tank steering at first. I'm eventually going to modify Roger's Ackerman control method from Sawppy, but my motor strategy is different so it will take some time.

Also with the rockers set up, before I mounted the wheels, I tested the articulation. In my opinion this needs some work and may be the weakest part of the whole contraption. We'll see how it works when everything is on the ground under it's own weight.

Here is another shot with the front wheels on:

Thursday, August 15, 2019

Mars Governance

We may be closer to coming up with a way to govern Mars effectively than was previously thought. 

Most people with even a casual interest in Mars have at least heard about Elon Musk's tweet that he will set up a direct democracy on mars, and that any law can be overturned with a 40% vote. That spawned a series of side conversations on Dr. Michael Shermer's podcast, Science Salon. Most of his guests shortly after the now-famous Musk tweet got asked what they thought about this issue. I've been listening to these podcasts while driving, in quick succession (about 2 a day) so Mars Governance question was hitting me in the face, and my subconscious was working on the problem. 

The biggest piece of the puzzle was Dr Shermer's Jan. 15, 2009 interview with Dr. Rachel Kleinfeld. She briefly mentioned having issues go to referendum if they are related to topics that the public has a high level of expertise dealing with (I'm paraphrasing from memory). 

I made a few PowerPoint slides to express my conclusions based on these discussions -- including a government outline -- and showed them to my cousin Dr. Elizabeth (Betsy) Carter, Assistant Professor of Political Science at University of New Hampshire. She had the fantastic suggestion to look at the current German system of government, which really brought this concept home. 

The presentation can be seen in PDF form on my Github at

Like most of my work, this is licensed with a public domain license, so anyone can do whatever they want with it without asking my permission. Including Elon, hopefully. 

Slide #2 from the presentation can be seen below. Click on it for better quality.

Sunday, February 10, 2019

QMRD3: The Rover Testbed

To support the Mars Drilling Project (discussed in the previous post), I have started building a rover testbed that I'm calling QMRD3 (Qualification Model Rover Demonstrator for Deep Drilling). This is a 4x scale copy of the Sawppy rover by Github user Roger-Random. Due to the size difference, several changes (mainly relating to motors and power transmission) have been made and an entirely different motor strategy is required. You can find more about Roger's original Sawppy rover at and

This rover was born out of the necessity for a mobile testbed with flexible mounting options, but is turning into quite a project, both in the amount of work involved as well in the many ways that it represents the bleeding edge of home-workshop additive manufacturing capability. For example, each wheel weighs 5kg and takes 4 days to print (0.8mm nozzle, 0.4mm layer height, 1.2mm extrusion width, single wall and 10% infill), with a material cost of ~$100. A screenshot with the details of the wheel print is below. If you are inclined to build a rover like this, the wheel should be your deciding factor. It is by far the most expensive and largest printed component.

The Rover Chassis has reached Version 1.02 and all components have been prepared for the larger size. A Github repository for QMRD3, containing STLs as well as the Fusion360 archive is available here:

Also of note is the 22mm skateboard bearings used extensively on Roger's Sawppy rover have been replaced with 88mm 3D printed gear bearings. The bearings are licensed separately from the rest of the rover and the files can be found here:

The drive motors are from makermotor and are available at: while the steering motors are from Amazon seller STEPPERONLINE and can be found by searching for the following listing: STEPPERONLINE 47:1 Planetary Gearbox Nema 23 Stepper Motor 2.8A. The mounting bracket for the stepper motor is required and will match up to the bolt pattern on the steering corners.

The Sawppy was designed with a $500 budget in mind, it appears that the budget moves linearly with the scale at this point, but the scrap costs from prototyping also do. If you want to build one of these I would plan on it costing around $5,000. Eventually the cost could be reduced to $2,000 from lessons learned, etc.