On 17/05/2018 20:26, Chris L Peterson wrote:
On Thu, 17 May 2018 10:37:52 -0700 (PDT), Quadibloc
wrote:

On Wednesday, May 16, 2018 at 11:59:29 PM UTC-6, Chris.B wrote:
On Tuesday, 15 May 2018 08:57:15 UTC+2, Quadibloc wrote:
On Saturday, May 12, 2018 at 1:48:16 AM UTC-6, RichA wrote:

http://www.bbc.com/news/world-us-canada-44090509

It is possible the guys working on it also had other duties.

Note that there were likely not as many people working on the project as would
be working at a drone manufacturer designing their next product.

And this drone had to be super reliable, and it had to work in the atmosphere of
Mars, which, as the article noted, is a *lot* less dense than that of Earth.
(The article said 100x; I thought it was more than that.)

Mars' atmospheric pressure is 6% of Earth's.

I just checked. 0.6% of Earth's, I'm afraid.

That's true for pressure, although the density is more relevant to the
performance of wings (moving or fixed). The atmospheric density at the
surface of Mars averages 1.6% that of Earth's. That's about the same
as the density at a height of 30 km on Earth. That's right in the area
that the highest winged aircraft have flown.

And well above the normal helicopter flight ceiling.

I guess given a drone on the Earth with say 0.1 diameter rotors then one
on Mars would need rotors spinning at the same rate but about 8x larger
and weighing the same to generate the same net lift as on Earth.

I expect the engineering challenges of making something that will work
OK in such a thin atmosphere more than explains their delays. You would
have to test it in a rather large vacuum chamber too (or up at 30km).

--
Regards,
Martin Brown