AstroTalk Episode October 13, 2016

Opportunity Rover to Explore Mars Gully, Factors in Travelling to Mars

2:58pm - 3:29pm

The NASA Mars Opportunity Rover is just about to drive down into a large gully to look for signs of water. No space vehicle has driven down a gully on Mars before. The gully lies in the Bitterroot Valley, on the western rim of Endeavour Crater, a basin which was thought to have been excavated by a meteor impact billions of years ago. In craters that opportunity previously examined, it never drove down into the craters. This is the first time that Opportunity will actually drive down into one of those craters. The water in the crater is thought to be below the surface. If it wasn't beneath the surface, it would have already evaporated into the thin Martian atmosphere. The gully is the length of 2 football fields, and scientists are confident they will find signs of water in the gully.
In other news, a lot of consideration needs to be given to many factors in travelling to Mars. When humans went to the Moon, for example, the spacecrafts did not travel very fast: in relative terms that is. When travelling to Mars, the spacecrafts will have to travel at a far greater speed, because Mars is so much farther from Earth than is the Moon. Since the spacecraft's speeds will be much higher, a lot more of something will be needed to brake the spacecraft and slow it down enough so it can begin to orbit Mars. Can the firing of rockets brake the spacecraft enough? Maybe not, because that would require too much fuel, and these spacecrafts cannot carry endless supplies of fuel. NASA is therefore working with a new type of power fuel called a scudaradite. These materials can conduct electricity like a metal, heat up like a glass, and generate size-able voltages. Materials such as this new thermo-electrical material is apparently hard to come by. This material is being designed at the Jet Propulsion Laboratory in Pasadena. Scudaradites are composed of heavy atoms like Antimony. They can be used as thermocouples, which generate voltage due to the difference in temperature between its components. Thermocouples made of scudaradites need a lot less of a difference in temperature to produce a useful amount of power, so they are more efficient at generating power. This type of performance would be very advantageous on a long term mission to Mars. An RTG generator, which is now being tested, contains 768 thermocouples all facing in the same direction. The scudaradite material would replace the now used Teluride in the RTG generator, and would provide better heat generation.