I'm doing a report on the mars rovers and am wondering what material did NASA use to construct spirit and opportunity's wheels. Was it aluminium? Rubber? Titanium? Magnesium? I don't know. Can't find any information on the topic so hoping you guys have some good idea of what they're made of.
1$\begingroup$ First guess would be aluminium, Rubber/plastic has problems in the temperature range of flight and Mars, Titanium is problematic to fabricate with unless you really need it's properties. Magnesium can catch fire and otherwise be chemically exciting which is not good on a wheel rolling across an unknown surface. $\endgroup$– GremlinWrangerOct 27, 2019 at 1:29
2$\begingroup$ I believe this answers your question: space.stackexchange.com/a/13232/32284. In short the wheels were made out of 10'' aluminium. $\endgroup$– Star ManOct 27, 2019 at 1:29
$\begingroup$ @GremlinWranger There are some kind of polyimides usefull for space applications, Solimide foam was used. Not an ordinary cheap plastic with low temperature resistance. $\endgroup$– UweOct 28, 2019 at 15:08
Aluminum and foam according to this page that describes the wheels as manufactured from a single Aluminum block with foam inserts into the spiral suspension system spokes. The black surface of the wheel itself is just an anodized coating.
Interestingly the wheels are described as being by design less effective in sand than they could have been by having curved rather than square cleats, to avoid getting snagging while crossing the airbags.
Given both rovers ended up getting bogged in sand possibly another data point in the decision to land later rovers under power rather than by airbag, since it avoids needing to compromise the wheel design this way.