4 Real time operations at the Viking Computer Facility One of the main problems with the Viking Mission was its success! Prior to landing, I suspect that most of us would readily have traded the chance of a multi-year mission for a guaranteed 90 day mission without hesitation. It the end of the nominal mission we were faced with four healthy spacecraft and an excellent flight operations team. During the next year or so, we at UW were content to continue receiving data from JPL in processed science form even though we had operational software to obtain meteorology data from the meteorology Front End Processor, FEP, tapes produced by the JPL UNIVAC 1108 system. However, if we were to be able to obtain meteorology data in the future, it was clear that we would have to implement some of the operational software which handled the raw spacecraft data stream from the Deep Space Network, DSN, since the flight operations IBM 360/75's were certain to be decommissioned soon. A minimal set of this software was implemented on the VCF's Prime for use in obtaining meteorology results from the meteorology science data format in the raw data stream and pressure from the engineering data format. While implementing this capability, changes were made in the data format and block lengths by NASA, which we included as options. In January of 1981, we began processing data on a weekly basis, including a comprehensive set of engineering parameters for the operations team at JPL. Data were provided to JPL by dial up access or by mail. In the next few months, we expanded the engineering processing, including plotting selected, and then all, engineering parameters. Prior to our conversion of the software, data were plotted by hand at JPL if at all. Around that time, it became clear that the lander might continue to function for many years and dedicated, part time, Viking staff members initiated a program to recondition the two dead nickel-cadmium batteries of the four on Lander 1. To assist in the rapid turnaround required for this effort to be successful, I proposed that we implement a direct, real time link between JPL and the VCF since the previous method was to mail tapes from JPL to UW. This was accepted and after several iterations, the communications configuration of Figure 3-8, Telecommunications and Data Acquisition System Support for the Viking 1975 Mission to Mars, The Viking Lander Monitor Mission May 1980 to March 1983, D. G. Mudgway, JPL publication 82-107 was implemented. The synchronous NASA communications codes were decoded and input to an AMLC port on the VCF using an Intel system. First testing of the system was accomplished on May 14, 1982 and our permanent installation was implemented in October of 1982. The only special provisions made on the Prime end were to increase the size of the AMLC buffer to around 1,000 bytes to preclude the possibility of buffer overflow. Since the data rate from Mars to Earth was 1,000 bits/sec, there was no need to assign a high priority to this task. With our real time capability, we were able to provide immediate analysis of the battery conditioning results for planning the following sequences in a timely manner. 5 Development of the Smithsonian National Air and Space Exhibit Prior to the establishment of the real time link, we had been displaying lander images on our AED 512 image processor. Once the planning for the link was initiated, Dr Farouk El-Baz of the Smithsonian National Air and Space Museum was consulted as to whether the Museum would like to have a weekly picture "Live from Mars", provided we could obtain the donation of an image processor. After a commitment of AED to donate an image processor I requested that Prime donate a used system for the Museum. After long negotiations with the various parties, and Stan Kent of the Viking Fund providing maintenance funds, a system was donated including two Prime microcoded MPC 4 controllers, to allow high speed DMA communications between Prime and the image processor. Microcode for the MPC 4 was written by Noel Cheney of the Atmospheric Sciences Department at UW, while we continued to operate 24 hours/day. To minimize impact to users and disruption of our continuous weather data collection and processing, initially the testing of MPC 4 microcode was done between 7 and 8:30 AM. To make the development of this code possible under such constraints, Dr. Harold Edmon of the VCF wrote a debugger for microcode development as well as a routine to down load microcode without cold or warm starting the system. User interfaces for the MPC 4 and image processing software were written by James Synge of the VCF. William Guest processed and generated the meteorology graphics that are included in the display and Neal Johnson provided in Viking data processing. The sequence of text, graphics and images that are presented at the Museum, were developed by Dr. Ted Maxwell of the museum, Rachel Tillman and me. Finally, I designed the overall system as well as convincing the interested parties to donate the required resources. Mission Operations Communications including Real Time. NASA Deep Space Network >> Jet Propulsion Laboratory >> University of Washington >> Smithsonian National Air & Space Museum, Washington DC. From "Telecommunications and Data Acquisition System Support for the Viking 1975 Mission to Mars, The Viking Lander Monitor Mission May 1980 to March 1983", D. G. Mudgway, JPL publication 82-107. ______________________________________________________________________ ______________________________________________________________________ Parameter V0-1 V0-2 ______________________________________________________________________ Number of days from launch to end of mission 1813.98 1049.52 Number of orbits of Mars 1488.0 706.1 Number of pictures recorded in orbit 36,622 16,041 BILLION data bits played back from 357.7 161.3 the tape recorders (including lander relay data) Tape travel across recorder heads, km 2955 1397 Number of commands sent by the Network 269,500 Number of tracking passes supported by the Network 7,380 Hours of tracking time provided by the Network, 56,500 _________________________________ Table 1. General Viking Orbiter Statistics ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ Event Viking 1 Viking 2 ______________________________________________________________________ Launch Aug. 20, 1975 Sept. 9, 1975 Arrival June 19, 1976 Aug. 7, 1976 Landing July 20, 1976 Sept. 3, 1976 Site Chryse Planitia Utopia Planitia Coordinates 22.3 N, 48.0 47.7 N, 225.8 Orbiter in orbit 1,509.9 days 718.8 days Lander active on surface 2,245 days 1,316.1 days End lander operations Nov. 13, 1982 April 11, 1980 End orbiter operations Aug. 7, 1980 July 25, 1978 Orbiter photos 51,539 Lander photos More than 4,500 Photo coverage 97% of planet with resolution of 300 m (1,000 ft) or better. 25% of planet with resolution of 25 m (82 ft) or better. Lander weather reports: more than 1 million Orbiter infrared observations: more than 1 million Orbiter weight: 2,325 kg Lander weight: 571 kg Orbiters built by Jet Propulsion Laboratory Lander built by Martin Marietta Aerospace Project managed by NASA Langley Research Center ____________________ TABLE 2