February 2, 2004
Press briefing about to start; notes when it's concluded. (The Q&A part is kinda sketchy because my connection was falling down. The first part should be pretty accurate, at least.)
Natalie Godwin: Opportunity has sent us the first 360 color image from the Meridiani Site and engineers have extended her robotic arm so that scientists can study the soil around her.
Jeff Johnson (science team): I am very pleased to announce this morning that the full 360° mission success panorama from Pancam acquired and on the ground. You may remember the Pancam mosaic from day one that Jim Bell presented was referred to as a "postcard" because it represented a kind of snapshot. Now we've completed a full mission success pan. (anecdote about tourists taking pano at grand canyon). This wonderful 360° panorama is in stereo and provides a real sense for "you are there" at the site and gives us a real sense of this bowl shaped depression that we're now in. So without further ado, let's go to the image. This image will start off zooming into the left portion of the image, we'll go right into the edge of the outcrop with all those airbag retraction marks in view, with really dark soil -- this is darker region than we saw at the Gusev site. This is the outcrop as it scrolls that we'll be really interested in spending quite a bit of time trying to document and map as field geologists, the whole outcrop. More bounce marks with the wonderful seams of the airbag itself. As we come upon some slightly larger portions of the outcrop, rocks that are perhaps a few feet in height. The entire outcropping itself is actually very tiny and the layering that we see in the outcrop will be very interesting to us. This area of expanse, looks like there may be some variations. And these wonderful airbag marks here are probably the entry point with the volleyball like textural? and the brighter areas that come in on the dunes there. Just an amazing site that we're still trying to figure out. Hopefully over next few weeks as the rover starts to do it's reconnaissance of the outcrop and sample some of its soils, we'll get a better idea of geologic history of this site. As much as we've been in awe of all of these wonderful Pancam pictures, I'd like to talk about Pancam's ability to do spectroscopy in visible and near infrared wavelengths. You'll remember that Pancam is two cameras. Let's go to that image. On each camera there's a filter wheel. The Pancams are the two dark objects on the outside of the camera bar in this image. See the navigation cams there too. Pancams only about the size of your hand. Filter wheel exposed in that lower image. Each Pancam has 7 positions so we have a total of 14 filters that we can use to image. Pancam is sensitive from blue light out into the near infrared, beyond where your eye can see, to about a thousand nanometers or one micron. Compare that to mini-TES that can go from 6-30 microns. What can we get from all these colored filtered images. Simple case is that the dirt on Mars is very red, very bright in red wavelengths and very dark in the blue. We can do more by looking at how the brightness varies looking through these different filters we can get an idea of the geology. Especially if we want to try to unravel the geologic history of the site. Each mineral has a fingerprint in the near infrared visible spectrum. When we put together a spectrum using these 14 filters, we can compare with samples here on Earth to get an idea of what minerals the area is composed of on Mars. So what does Mars look like. This image shows the calibration target, sundial which is approximately truecolor. I'll focus your attention on the color chips in the green, the red, blue, and the yellow. Plot is two types of data. The solid lines where the colors correspond with actual color chips are spectra acquired of color chips in a lab on earth. These dots are the brightness values from each of the filters that we acquired from actual Pancam data. Those dots are lying right along the laboratory Earth measurements and that's what we like to see. The camera is very well calibrated. So the spectra we extract from Mars will give us a very accurate idea of the true spectral characteristics of that surface. Next slide shows Gusev and a bit of the variability we seeing in these 14 color spectra. In the upper left is the magic carpet region. Focusing in on the rock to the left of the airbag retraction marks. Colors in the lower image correspond to spectra on the right. We've extracted spectra from those spots. You can see that the yellow area is the soil in front of the rock which is very bright in the infrared. A little green area is on top of the rock is even brighter. Rock itself, blue spectrum is very dark.