Marsokhod Planetary Rover Status Report

2 February 1995

Written by John Garvey

The biggest event of the week so far has been the Mars Day demonstration of the Marsokhod hosted by JPL on Tuesday, 31 January. After some annoying set-up problems associated with low power bus voltages that kept resetting the on-board computer, the vehicle operated for several hours before a crowd of several hundred observers and extensive print and television media. In contrast to the originally scheduled date of 10 January, the weather was perfect. The relatively fast set-up time at JPL (approximately 30 minutes after the rover arrived at JPL on a flat-bed truck) also strengthened the team's confidence with respect to implementing next week's deployment operations in Kilauea.

The following day (1 February), Ames held a working group meeting for the science team that will conduct the Mars-oriented tests on 13-15 February. The participants addressed site regulations, test requirements, daily schedules, technical constraints and contingency plans for inclement weather. Butler Hine (Ames) also gave a quick summary of the science and operations lay-out that they have set up in the Ames Intelligent Mechanisms Lab for the tests.

Many final hardware tasks are underway in preparation for this coming Monday's rover shipment. Spares for the batteries, motor control modules and the associated VME board, motor amplifier units, and rover chassis components have been ordered and are arriving on a daily basis at McDonnell Douglas' shipping gate. Final wiring harness adjustments are nearly finished, enabling completion of the arm software integration effort in the next day or so. A complete systems check involving the Marsokhod at MDA and the Ames Virtual Environment Vehicle Interface (VEVI) control software (hosted on a workstation at Ames) is presently scheduled for tomorrow (Friday) afternoon.

The big open issue continues to be the PIN (Primary Interface Node) site communications network for the JASON phase of the Kilauea operations. At the local level, the 486-based software and the on-board rover control software have been thoroughly checked out for several weeks over MDA's local Ethernet. However, questions still remain with both the use of the Chameleon software for TCP/IP level formatting (MDA and Ames have been using Wallagong for their internal development activities) and the integration of the transferred data with the WilTel/EDS network-level protocols. The goal is still to try to ship an initial software package by early next week, although there are still several weeks to go before this capability is absolutely required for JASON-related operations (the planetary science testing that proceeds JASON does not utilize this capability and is scheduled to be validated by the end of tomorrow). Karl Pfitzer (MDA) and Hans Thomas (Ames) are working this issue. Additionally, Dave Burnett and Gary Glover (MDA) are presently on their way to Dallas to participate tomorrow in a general PIN meeting organized by EDS and to discuss any other open action items that might be identified.

Also on the software front, Gary has finished a preliminary version of a PC-based rover VR-type simulation (known in the MDA Robotics lab as GLOVI, of course). It presents a rover that can be commanded by a mouse-driven cursor to traverse through a simulated planetary terrain. The JASON Foundation requested this capability to help students learn about the Marsokhod operations while they are participating in the interactive PIN-site control sessions. This software is far from being a final product, but in the interest of getting feedback on how to improve it for future operations, we are distributing it on a limited basis to participating parties (we had originally planned to make it widely available as freeware, but licensing issues associated with the rendering software routines preclude that option at the present time).

In the science arena, a solution was achieved for satisfying a science imaging requirement that has received a high level of attention in the last week. Specifically, Dave Burnett obtained a 35 mm lens for the arm-mounted micro-camera that enables images that surpass the 0.1 mm per pixel resolution goal that the Mars science team has specified. There had been recent concerns that achieving this degree of resolution, which was identified as the result of the Amboy crater rover tests last spring, might prove impractical in this round of testing. For those with access to the team file server, you can check typical images, as presented in files micro22.gif, micro23.gif, micro24.gif, micro25.gif and rock1.gif to get a better appreciation of this capability (the numbers in the micro*.gif files refer to the distance of the lens from the imaged plane). The schedule for the near-term is:

February

2 - finish harness for the higher-capacity power converter
- evaluate latest arm control software configuration
3-5 - end-to-end test between Ames and MDA to test remote rover control with VEVI
- hard mount the Kodak DCS-420 imager and a mockup of the JSC EGA instrument
- PIN site general meeting at EDS facilities in Plano, TX
- burn on-board rover software into EEPROMs
- continue working on the protocol integration for the PIN site communications
- install wrist roll motor in arm
6 - deliver rover and associated equipment to shipper for delivery to Hawaii
- advance team (Dave James and Greg Loboda) flies to Hilo
7 - familiarization meeting at HVO with park rangers
- status teleconference
8 - science operations simulation
9 - rover, related equipment and rest of field team arrives at Hilo
10 - field operations walk through
11 - end-to-end test communications test between Ames and the Marsokhod in the field
13 - start Mars test phase

Finally, we continue to receive information that the selections for NASA's Discovery program will be announced in about two weeks, which would be an extremely appropriate time if the lunar rover mission is one of those chosen.

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Gene Carl Feldman (gene@seawifs.gsfc.nasa.gov) (301) 286-9428
Todd Carlo Viola, JASON Foundation for Education (todd@jason.org)