I was very interested when an MSL flight spare wheel appeared in a sandbox in our High Bay a few months ago.
That is very, very cool -- thanks for sharing the photos
I think this warrants a new thread, since it will undoubtedly be a recurrent topic of discussion as they develop Mars 2020! Getting to work on that now...
I'm a PhD in microbiology, not mechanical engineering, but I have a wheel design of a significantly different geometry (not just changing grousers or their shape) that I think could be quite interesting for NASA to at least see. Anticitizen2 or anyone else at NASA--I'm happy to speak with you. I'd post my design here, but that would be a public disclosure and kill anyone's ability to patent it.
Floyd Dewhirst, DDS, PhD
Senior Member of Staff
The Forsyth Institute
Professor of Oral Medicine, Infection and Immunity
Faculty of Medicine, Harvard School of Dental Medicine
A few more wheels in - looks like standard number of grousers and 2/3 of MSL's width.
Each wheel is printed in 5 segments, to explain the big seams you can see
I had been waiting for these 'weird' wheels to start coming in. A bunch more are expected, as the experimenting gets crazy before it starts honing in on a goal in a year or so, I'd guess.
Thanks for sharing these photos. In the first image, the rear wheel seems to slope down from one rim to the other (that is, it seems to have a smaller diameter on one side than the other) -- is that real or a distortion in the photo?
Distortion from the photo, I was standing to the left. So far they're all MSL radius, no varying radius.
Just to be clear, I'm not involved with this testing program. I work in the same building, it caught my eye, and I've asked some of the people about the status of the testing- e.g. If they're expecting more wheels soon. All comments have been my opinion or observation
I'm certain that it's only the test article wheels that are being 3D printed, to rapidly run through a wide variety of tread designs in the sandbox. Anything sent to Mars will probably be machined titanium or aluminum, like the previous wheels.
Yes, the printed plastic ones are only for testing.
Testing many iterations of machined aluminum wheels would get insanely expensive.
This is why, as shown in the very first picture, they tested an MSL flight spare against a 3D printed copy to first get some knowledge about the performance difference between materials before moving on to different printed designs.
It also costs an order of magnitude more than printing a plastic one.
New wheel on the scarecrow. Enlarged crop attached.
https://pbs.twimg.com/media/CataYkMUcAA8nd5.jpg:orig
Last update from me on this topic, unfortunately. I'm no longer working next to the wheel testbed, but hopefully I can get some pictures of InSight or OSIRIS-REx
Wow, those grousers are much deeper than previous wheels. People always told me the grousers only needed to be as long as the grain size was large, which is why the Curiosity grousers were so shallow. I guess that rule of thumb isn't true?
Since the Rover 2020 design just passed review, are there any more concrete details available on the final wheel design, or is that something that can still be very much in flux at this stage even under review? I would imagine the review team paid particular attention to that aspect of the presentation.
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