Any ideas where else I might find a replay of today's (8/22/12) press conference? I hate to miss one.

hydrogen was only found on the first shots to Coronation, so it must be a very thin surficial layer. I was wondering: could this be contamination from hydrazine (N2H4) from the Skycrane exhausts?

One of the objectives of the Viking mission is to determine the existence of extraterrestrial life on the Martian surface. A retrorocket engine powered by catalytic decomposition of hydrazine fuel will be employed to soft-land the scientific instrumentation on the surface of Mars. It was imperative, therefore, to determine if hydrazine and its breakdown products in the engine exhaust would affect organisms at the sampling site. ...

In the final approach of the Viking lander on Mars, the retrorocket engine to be used is powered by a catalytic decomposition of hydrazine fuel to gaseous products by a stochiometrically undefined process of the type:

(2a+b)N₂H₄ -> 2aNH₃ + (a+2b)H₂ + (a+b)N₂

It was estimated that at the landing site NH₃, the major product, might reach fleeting concentrations of approximately 30 percent of the Martian CO₂ atmosphere. In such an atmosphere, the reaction also generates aniline, hydrocyanic acid, and in all probability carbazic acid (H₂NNHCOOH) and ammonium carbamate (NH₄OOCNH₂). Further work by Martin Marietta Corporation and others confirmed that the products depended on the grade of fuel used and the nature of the atmospheric environment. Purification of the "mil spec" hydrazine fuel lowered the yields of the decomposition side products, especially HCN. Nevertheless, it appeared that HCN at levels of 200-500 ppm might be encountered in the atmosphere at, and immediately surrounding, the Martian landing site. The possibility also exists that hydrazine fuel could contaminate the landing site by lander tank leakage, by unreacted N₂H₂ in the engine exhausts, or by the impact of the deorbit propulsion tanks with the aeroshell.

Maybe Curiosity oughta just mosey on?

Reading up on ChemCam as suggested by Stewjack: done. Also read the next item (APXS) and now I wonder: what is the specific scientific deliverable of APXS relative to what ChemCam will be able to do? ....

Couple of Mastcam-100 frames are down:

The rest, looking toward Mt. Sharp are blurred:
http://mars.jpl.nasa.gov/msl/multimedia/ra...1_DXXX&s=13

The rest, looking toward Mt. Sharp are blurred:
http://mars.jpl.nasa.gov/msl/multimedia/ra...1_DXXX&s=13

The first and only known assessment of landing site contamination from rocket exhaust gases was performed experimentally, during the development of the Viking lander... During the assessment, engineers changed the descent engine nozzle design (which was subsequently used on the Viking landers) to diffuse the gas and reduce soil erosion as the lander approached the surface. The results of chemical analysis of the soil samples showed measurable amounts of hydrogen cyanide (HCN), which were traced to aniline impurities in the Mil-Spec fuel. Switching to a purified hydrazine fuel eliminated the unwanted HCN, and that fuel has since been the standard for all subsequent Mars soft landers to date, although tests also showed that the purified hydrazine would contaminate Mars landing sites with ammonia (50 to 500 ppm), N₂ (5 to 50 ppm), and possibly a small amount of water (quantity not measured). The large amounts of ammonia trapped in the soil would make interpetation of organic analyses more difficult. ...

The rocket exhaust study conducted for the Viking mission also addressed gas dissipation from the soil after landing (actually release and diffusion)... The Viking Molecular Team set as criterion that exhaust gas contamination at a concentration above 10ppm be permitted to exist for no more than 2 days after landing...

No subsequent comprehensive analyses for retrorocket contamination have been performed. The Viking assessment results have served as the ad hoc basis for all subsequent NASA soft-lander missions...

The [MSL] sky crane is expected to use hydrazine retrorockets as did Viking, but it may have throttled engines rather than pulsed engines, which would reduce potential disturbances of soil. Nonetheless, the sky crane will require larger loads of hydrazine propellant for their payloads (200 kg compared with 85 kg for Viking) and will at least temporarily contaminate the atmosphere surrounding the landing site.

I know the mastcams can focus, and have autofocus. I've looked, but I can't find any information about how the focus is controlled. Do we get an out
of focus image because the camera is commanded to take a picture but the autofocus is turned off? Or was the focus distance set from JPL but to a value
that meant the image is blurred?

Chris

Parts of this one look sharper...I think http://mars.jpl.nasa.gov/msl-raw-images/ms...3000D1_DXXX.jpg