It seems Curiosity’s wheels are wearing out faster than expected and engineers want to know why.
It seems Curiosity’s wheels are wearing out faster than expected and engineers want to know why.
The increasedwear recently appears to be because the rover was traveling over rougher terrain. Nonetheless, JPL engineers are going to monitor the rover’s travel and wheel damage more closely in order to gauge that wear better for future travel.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
It seems Curiosity’s wheels are wearing out faster than expected and engineers want to know why.
The increasedwear recently appears to be because the rover was traveling over rougher terrain. Nonetheless, JPL engineers are going to monitor the rover’s travel and wheel damage more closely in order to gauge that wear better for future travel.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Those holes don’t look good.
You can even see the ring around the tire made by the attachment ring on the inside of the wheel.
Eventually it will start to come right through the “tire” if you want to call them that.
All this trouble just to save weight. They are driving a ton of rover on paper thin tires. Over rocks that have never really been through an environment that would have smoothed them out.
Its like driving on sandpaper and hopping it doesn’t eventually wear through the tire material.
Three miles and its starting to fail.
I would have gone with one less camera or something in order to keep the tires working.
Think of it this way.
The flat parts of that tire are as thin as a business card.
And when dropped on sharp rocks they have no way to absorb the impact.
A rubber coated tire has the rubber to absorb the impact and spread it out over a larger portion of the surface.
Think of this.
A standard rubber car tire deforms as it contacts the ground. Thus it will have anywhere from 4 to 6 inches by 6 to 8 inches of surface area contacting the ground depending on the tire and air pressure. And as it rolls over a sharp rock the tire gives way and forms around the sharp object.
But these solid tires have no give. On a hard flat surface they have a contact area of less than an inch square and in some cases only a fraction of that. Such as when it is on one of its “treads”.
These solid tires work great on sand. the sand molds around the tire and spreads the contact area out to a safe level. But as soon as it has to go over a hard object that area is immediately reduced to a pencil point of area.
Lets assume each wheel carries the same weight of the rover. 2000 lbs divided by 6 wheels would be about 330lbs per wheel.
All 330lbs would be concentrated into a pencil tip sized area. An area only as thick as a business card.
How hard is it to push a nail through a coffee can?
The cream of the crop of our engineers thought of this and forgot to test it out.
A logical guess would be the engineers considered that, perhaps they thought that the weaker Mars gravity would reduce the impact of sharp rocks enough….
http://www.planetary.org/blogs/emily-lakdawalla/2013/10022101-theres-a-hole-in-the-wheel-dear-liza.html
This engineer is of the opinion that even if the wheels fell off the rover would still be able to move on those little bent spring/suspension things that attach the wheel rim to the hub.
The problem with her idea is that if the rover ever does goes over soft ground it would then sink and be permanently stuck.
And it has miles of sand to drive over to get to the mountain its supposed to drive up.
They were made that thin just to save weight. Thats all and even NASA admits it.
NASA needs to get off its single monolithic launch idea and embrace the idea that they can make more than one launch for things like this.
Launch the payload you want to get to Mars into LEO and then launch a rocket engine to boost it out of orbit and on to Mars.
As long as NASA plans for it they have shown the ability to dock anything to anything in orbit remotely and or autonomously.
Its either that or just launch the needed payload on a bigger rocket. They will just have to accept that at times some possible payload capacity might not be used. They don’t have to fill it up to 100% capacity in the false thought that its saving something.
In the end, from everything I have found out about the thickness of the wheels. They only saved a few ounces of weight. They could have doubled the thickness for just a few ounces.
I’m more than likely making something out of it than it really is, but really, can’t they just add a few more pounds of fuel to the rocket to cover the few extra ounces and fire it a little longer?
Thats all the private industry is doing.