(Llano de la Paciencia)

Today Nomad returned to the control of drivers at the Carnegie Science Center in Pittsburgh. We were excited by the propect of covering many kilometers today, as compared with the relatively short distances covered during the science week. And we did cover our largest distance to date, somewhere between 3 and 5 kilometers; more precise measurements will come with further processing of our telemetry logs. We expect to cover even greater distances in the days ahead, as we continue to improve procedures for starting up, refueling, transferring remote control, and general operations. As one of our stateside team members put it, "Ah, waiting...seems to be the basic component of this trek!" We will change that situation.

Unfortunately, some types of waiting are inevitable. Several times today the Carnegie Science Center drivers managed to maneuver Nomad into areas with very soft soil in small hills. That meant that Nomad spent some time trying to climb without getting very far, though one team member says that given more time Nomad could have climbed out of the holes it was digging. But from a remote station, it can take a while to realize that you have not moved for the last few seconds. So it took some time to gingerly work Nomad out of those soft hilly areas into more traversable terrain.

One way we plan to avoid waiting is to have Nomad drive itself during some of the downtimes at the remote control stations. That will become possible thanks to Nomad's onboard navigation system, which is finally becoming completely integrated into the vehicle. Today Nomad drove autonomously for about 560 meters while the folks in Pittsburgh had lunch. And of the distance covered by remote drivers, over 1600 meters were driven in Safeguarded Teleoperation mode. That's the mode where the driver offers a "suggested" steering direction, but Nomad has the final say on where it's safe to go. We tested it out first thing today by having the Pittsburgh drivers aim straight at team member Alex Foessel. We placed Alex about 6 meters ahead of the vehicle a couple times, and had the Pittsburgh folks try to drive toward him. In spite of their best efforts, Alex survived unscathed as Nomad automatically veered around him.

The navigation system does have some peculiar quirks. For instance, one of the folks at the Science Center noticed that Nomad was steering away from its shadow at 1720 hours. The reason for that behavior is quite apparent from the imagery; with the Sun so low in the sky there is little ambient (reflected) light, so the area covered by shadow is quite dark. Hence there are no recognizable features in that region and Nomad, being conservative, tries to steer away from it. Still, the image of Nomad being afraid of its own shadow persists.

But most imporant, we got a new doorknob! Our Operations Truck was delivered without its external doorknob, which must have been dislodged sometime during transport. Until today, we had been forced to use the big wall-sized loading door, or to knock loudly on the small door hoping someone would open it from the inside. Now we can enter quite easily, but old habits die hard; people *still* knock obstinately on the door, demanding to be let inside.

Tommorow we look forward to an early start, so we can cover as much ground as is possible.

Last Modified on: Mon Jun 30, 1997