February 9, 2004
Natalie Godwin: Both rovers are on the move on Mars. 3:30am at Gusev, 12 hours later on the other side of Mars.
Tim McElrath: As you saw with Spirit, a variety of ways to perform localization on the surface. I'm going to talk about radio data. We'll also hear about descent images and IMU propagation, then post landing MOC images. First graphic shows THEMIS imagery. Blue ellipse is based on tracking during approach. 44 miles long, 5 miles across. When we got to Mars we were fortunate and had two DSN complexes in view. So we had tracking data from Canberra and Goldstone so that gave us differenced one-way doppler data. 5 minutes after EDL we got the tracking data all the way down to parachute deploy. That's the black ellipse which we were able to come out with about 35 minutes after landing. That's about 5.3 miles by 1.4 miles. That confirmed several things we'd seen with relatively late parachute deploy and narrow descend. Needed to wait 'till we were on the surface to get a much closer tie on where we were. On the surface we have 2-way doppler tracking DTE and we also have UHF 2-way doppler tracking to Odyssey which comes over twice a day. That little white ellipse is 145 ft. by 3 ft. from two Odyssey passes and 6 DTE communications spread over 3 sols and that pins us down quite well in an inertial frame but problem is that the map is not tied in well with the inertial frame, could be off as much as a quarter mile but turns out much better at only about 500 feet. Since we've got the map tie solved for this location, we can get the same type of location resolution if we need it.
Andrew Johnson: I'm gonna talk about the second way we determine position. This is using EDL telemetry. This is a mosaic of the three DIMES descent images and a line showing the path that Opportunity took. Over to the left is the direction we're coming in from, going basically East but near the end start moving to North and when we cut bridle we are actually moving North. Another view of the same scene what it shows is the descent trajectory coming down and bouncing along the surface. Final graphic is another blowup of the bouncing across the surface. 26 bounces official number of bounces. We bounced along and some how ended up in this crater :D We rolled 200 meters, about 1/8th of a mile for more than 1 minute. Velocity when we cut loose of the bridle was 9m/s N 2m/s W which is 20mph N 4.5mph W.
Tim Parker: How many golfers out there ;-) First graphic is to look at the horizon views from lander and compare to features seen from orbit. Mosaic of 3 images, far right is 18-20 m/px THEMIS vis image. The next image covers most is a MOC image and the final image canted at an angle there is one of the DIMES images. Here is the reconstruction based on triangulation to three craters visible on the horizon. One was visible pre-standup mission success pano. The other two were seen in post-standup pan. The large crater to the east was obstructed by the rim of the crater we're in. This was difficult because the crater we're at was so small that we can't identify features in it's rim to compare to orbiter views. We've zoomed in here on the last prediction from DIMES team on where the first bounce would have occurred in green and the blue diamond is the last nav solution for where we wound up. That is a remarkably close match to where we actually are with respect to the surface. It's only 120-130 m from the center of the crater. That's far down in the noise with respect to our precision of tying the Mars surface to the geodetic grid.