by JohnD » Fri Jun 27, 2014 1:45 pm
Hookedonfishing wrote:First, awesome picture and i never miss an APOD!
Observation - one of the wheels has a hole and is damaged.
Question - the rover is powered by nuclear - are we polluting a planned destination with radiation everywhere it goes?
Yes, i am dumb but curious.
Yes, Curio has several holes in its wheels! As they are not pneumatic they don't matter, unless so many occur that the structural intergrity of the wheel is compromised. The holes have alarmed the driving team, whihc now plans drives to avoid as far as possible the many sharp rocks on Mars' surface. Tjis wasn't a problem with Oppo or Spirit, but Curio is much heavier and has much bigger wheels.
The nuclear energy source on Curio is not a type often used on Earth, not because it is dangerous, but because it is relatively inefficient. It is a radioisotope thermoelectric generator, thta uses the heat of nuclear decay to get voltage directly from thermocouples. This design is simple with no moving parts, light and long lasting. America used then as long ago as the Apollo program, and Russia has used them for unmanned light houses etc. A conventional Earthbound reactor is far more efficient, by working at much higher temperatures to raise steam to run turbines, but is enormously heavier.
See:
https://solarsystem.nasa.gov/rps/rtg.cfm
The webpage goes into safety, and the various incidents where radiation has leaked because of damage or tampering. But think on't! If it leaked radition in any quantity it could not be fitted to the vehicle when it was built, nor would it be safe to install in the launch vehicle. Here
http://commons.wikimedia.org/wiki/File: ... rement.jpg is a picture of a worker measuring the radiotion from a RTG. She is not wearing protective garments!
Do not forget either that as Mars lacks an atmosphere or a magnetosphere, the surface receives a significant solar radiation dose, measured by Curiosity itself at 0.64milliseiverts/day.
http://www.scientificamerican.com/artic ... s-managea/ This is twice the 'cosmic' radiation we get on Earth, but a fifth of all we receive!
http://en.wikipedia.org/wiki/Background_radiation
John
[quote="Hookedonfishing"]First, awesome picture and i never miss an APOD!
Observation - one of the wheels has a hole and is damaged.
Question - the rover is powered by nuclear - are we polluting a planned destination with radiation everywhere it goes?
Yes, i am dumb but curious.[/quote]
Yes, Curio has several holes in its wheels! As they are not pneumatic they don't matter, unless so many occur that the structural intergrity of the wheel is compromised. The holes have alarmed the driving team, whihc now plans drives to avoid as far as possible the many sharp rocks on Mars' surface. Tjis wasn't a problem with Oppo or Spirit, but Curio is much heavier and has much bigger wheels.
The nuclear energy source on Curio is not a type often used on Earth, not because it is dangerous, but because it is relatively inefficient. It is a radioisotope thermoelectric generator, thta uses the heat of nuclear decay to get voltage directly from thermocouples. This design is simple with no moving parts, light and long lasting. America used then as long ago as the Apollo program, and Russia has used them for unmanned light houses etc. A conventional Earthbound reactor is far more efficient, by working at much higher temperatures to raise steam to run turbines, but is enormously heavier.
See:https://solarsystem.nasa.gov/rps/rtg.cfm
The webpage goes into safety, and the various incidents where radiation has leaked because of damage or tampering. But think on't! If it leaked radition in any quantity it could not be fitted to the vehicle when it was built, nor would it be safe to install in the launch vehicle. Here http://commons.wikimedia.org/wiki/File:RTG_radiation_measurement.jpg is a picture of a worker measuring the radiotion from a RTG. She is not wearing protective garments!
Do not forget either that as Mars lacks an atmosphere or a magnetosphere, the surface receives a significant solar radiation dose, measured by Curiosity itself at 0.64milliseiverts/day. http://www.scientificamerican.com/article/radiation-on-mars-managea/ This is twice the 'cosmic' radiation we get on Earth, but a fifth of all we receive! http://en.wikipedia.org/wiki/Background_radiation
John