. ' Telecommu,nications ,and-.\ I Data .' .. Acquisition. Systems Support for , . ' \ ' , the Viking 19-75 Mission to Mars,- The Viking Lander Monitor- Mission. ' May 19801,983March to I ~\ D. J. Mudgway I ,- runsn , National Aeronautics and Space Administration Jet Propulsion Laboratory ' , California Institute of Techno,logy -.Pasadena] California ' L. Telecommunications and Data Acquisition .Systems Support for the Viking 1975 Mission to Mars A recent panorama taken by the cameras of Viking Lander 1 on the surface of Mars. The picture is a mosaic of six images taken on separate occasions over the period June through August 1982. JPL PUBLICATION 82-1 07 Telecommunications and Data Acquisition Systems Support for the Viking 1975 Mission to Mars The Viking Lander Monitor Mission May 1980 to March 1983 D. J. Mudgway May 15, 1983 National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California The research described in this publication was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. PREFACE In late 1976 therewere two Viking Landers and two Viking Orbiters in full operationon the surface and in orbitaround the planet Mars. Of thesefour spacecraft,only the Viking Lander 1 was activeinto October of 1982. As the Thomas A. MutchMemorial Station, this spacecraft represented the United States' presenceon Mars. As theViking Lander Monitor Mission (VLMM), it gatheredand regularly transmitted to Earth imaging and meteorology data relative to its local Martianenvironment. This report continues the description of the tracking anddata acquisition support for the Viking Mission to Mars published in five previous volumes,which are listed in thereferences. The first volumedescribes organization, planning, implementation, and test activity from inception of the Project in 1969 tolaunch operations in 1975. Cruise activity from the launch of twospacecraft to the landing of Viking 1 in July 1976 is described in Volume 11. The third volumecovers the landing of the secondViking Lander and Mars planetary operations for two Orbiters and two Landersthrough the end of the prime mission in November 1976. VikingExtended Mission support activity from November 1976 through May 1978 is described in Volume IV. FromJune 1978 through April 1980, VikingMission Operations were conductedunder various names related to the condition of the remaining space- craft andthe funding available to support mission operations. This period is described in JPL Publication 82-18. The Deep Space Networkcontinued to supportViking from May 1980 to the pres- ent(March 1983). This phase of the continuing lifeof the Viking Project was termed,theViking Lander Monitor Mission, and was expectedto continue through the year1994. However, the spacecraft failed in November 1982,and in March1983, the mission was considered to have ended. In this document, thetracking anddata acquisition support for the Viking Lander Monitor Mission from May 1980 to March1983 is described together with an overviewof :'the science results. The eventsleading to the failure and theNet- work'sefforts to recover the Lander signal are also included. / &&0 N. A. Renzetti V ABSTRACT From May 1980 until theViking Lander Spacecraft failed to transmit a down- link to Earth in November 1982, the Deep Space Networkprovided tracking and data acquisition support to the Viking Lander Monitor Mission (VLMM). Thisreport gives the background for the VLMM anddiscusses the technical and operationalaspects of the tracking and dataacquisition support that the Network was calledupon to provide. An overviewof the science results obtained from the imaging,meteorological, and radio science data isalso given. The reportconcludes with a description of the intensive efforts that were made torecover the mission from November 1982 until the effort was discontinued in March 1983. vi CONTENTS I. INTRODUCTION ............................ 1-1 I1 . BACKGROUND ............................. 2-1 I11. DSNSUPPORT ............................ 3-1 A . OPERATIONS .......................... 3-1 B . CONFIGURATIONS ........................ 3-5 C . REAL-TIME LINK TOTHE UNIVERSITY OFWASHINGTON ........ 3-5 D . AUTOMATICS-BAND DOWNLINK ................... 3-10 E . THE VL-1 RECOVERYEFFORT ................... 3-12 IV. VLMM SCIENCE RETURN ........................ 4-1 A . RADIOSCIENCE ......................... 4-1 B . METEOROLOGY .......................... 4-2 C . IMAGING EXPERIMENT ...................... 4-6 V . CONCLUSION ............................. 5-1 DEFINITION OF ABBREVIATIONS ........................ 6-1 ACKNOWLEDGMENT .............................. 7-1 REFERENCES ................................ 8-1 APPENDIXES A . SAMPLENEWS RELEASE ...................... A-1 B . VIKING LANDER MISSION SUPPORT EXTENSION REQUEST ........ B-1 C . VIKING LANDERMONITOR MISSIONDIRECT-LINK REQUEST SUMMARY ... C-1 D . VIKING LANDERMONITOR MISSIONDIRECT-LINK REQUEST DETAIL ... D-1 E . AN EXAMPLE OF VIKING LANDERSEQUENCE OFEVENTS ........ E-1 F . RECOVERYSTRATEGY LOG FOR VIKING LANDER 1 ........... F-1 G . ANNOTATED BIBLIOGRAPHY .................... G-1 H . VIKING FACTS ......................... H-1 vii Figures 2.1 . VikingLander ......................... 2-3 2.2 . VikingLander 1 Radio System. FunctionalBlock Diagram .... 2-5 3.1 . TypicalLander Pass ...................... 3-2 3.2 . VikingLander Uplink Acquisition Sequence ........... 3-4 3.3 . PredictedDownlink Signal Level From Vikins Lander 1 ..... 3-4 3.4 . VikingLander Telemetry Configuration .DSS 14 ........ 3-6 3.5 . VikingLander Tracking Configuration .DSS 14 ......... 3-7 3.6 . VikingLander Command Configuration .DSS 14 ......... 3-8 3.7 . Viking Lander Monitor and Operations Control Configuration . DSS14 ............................ 3-9 3.8 . Real-TimeData Transfer to University of Washington ...... 3-11 4.1 . TypicalViking Lander 1 PressureRecord ............ 4-3 4.2 . TypicalViking Lander 1 LocalAmbient Temperature Record ... 4-4 4.3 . Yiking Landers 1 and 2 Local AmbientPressure for 3 Martian Years ............................. 4-5 4.4 . VikingLander 1 ComparativeMars Images ............ 4-7 4.5 . VikingLander 1 Seven-Picture Sequence ............ 4-7 Tables 2.1 . VikingOrbiter 1 SurveyMission. 1980 ............. 2-2 2.2 . GeneralViking Orbiter Statistics ............... 2-3 2.3 . VikingLander 1 SpacecraftTelecommunication Parameters .... 2-6 3.1 . Comparative Success Rates for VikingLander Data Acquisition . 3-2 viii I. INTRODUCTION In late 1976 therewere two Viking Landers and two Viking Orbiters in full operationon and around the planet Mars. Of thesefour spacecraft, Viking Lander 1 hadthe longest life; it was still active in October1982. As the Thomas A. Mutch MemorialStation, Viking Lander 1 representedthe United States' presence on Mars. As theViking Lander Monitor Mission (VLMM), is continuedto'gather and regularly transmit to Earth imaging and meteorology data relative to its local Martian environment.However, late in 1982, thelander failed to respond to uplink com- mands for a downlinktransmission. Repeated attempts over a periodof four months failedto recover the lander signal. Finally, in March1983, the Viking I Lander Monitor Mission was terminated. Previoustracking and datasystems support for the Viking Mission to Mars aredescribed in Refs. 1-1 through 1-5. 1-1 11. BACKGROUND In July 1980, a pressrelease (Appendix A) announced theimminent conclusion ofthe Viking Orbiter 1 (VO-1) Mission and thebeginning of the VLMM. This an- nouncementmarked the end of the major Viking operations activity, and thebegin- ning of a new era of low-level support of anautomatic lander mission on an "op- portunity"basis. The requestfor telecommunications and data acquisition support fromthe Deep Space Network (DSN) for the VLMM through1990 is reproduced in Appendix B. A comprehensiveand informative account of the last year of the Viking Mis- sion is given in Reference 2-1 from the point of view of one of the scientists most closelyinvolved with theproject from its inception in 1969.Table 2-1 is takenfrom Reference 2-1 to show the principal mission events of the final months of Viking Orbiter 1. On August 7, 1980, at 2015 GMT, the Deep Space Station (DSS) 61 in Spain sent a command to VO-1 to turn off its S- and X-band transmitters. To satisfy international agreementsregarding uncontrolled radio transmissions from mace- craft, the s- and X-band transmitters wereturned off before ground control was lost. Subsequent RF searches atthe VO-1 frequenciesverified that both trans- mittersremained off. These searcheswere repeated several times over subsequent weeks, but no carrierswere detected. Thus ended the Viking Orbiter 1 Mission to Mars after five years of continu- ous operationalsupport by the Network. Throughout this period, the Network pro- videdcontinuous mission support and was effective in developingoperational techniquesto overcomeproblems caused by highly reduced staffing levels, obsolete hardwareand software, and the steady attrition of experienced Viking.operations staff. The VikingProject Scientist compiled the statistics of general interest given in Table 2-2 regardingthe two Viking Orbiters and the Deep Space Network support. VikingLander 1 (Figure 2-1) is located in ChrysePlanetia at 22"N,48" and was in anautomatic operational mode sinceMarch 1979, transmitting stored imaging andmeteorology data on activation from one ofthe deepspace stations.This