From left to right, Entry Analysis Team members JimJones, Bill Jones, Mike Doty, Ken Villyard, Mick Halland Bill Preston (standing) discuss the descent of theViking 2 Lander September 3. •

that conceived for the Viking Landers now operating onthe red planet, and the people responsible for makingthe system work to the best of its potential - monitor­ing and directing it through its paces - comprise theLander Performance and Analysis Group (L-PAG).

The Viking Landers were designed to be compatiblewith the environments of space flight, atmosphericdescent and landing, and surface operations - requiringthree distinct configurations for the same spacecraftsystem with corresponding distinctions between theirperformance profiles. The design had to employ highly

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Editor's Note - This issue of the Viking Status Bulletinis the first of a supplementary series to be dedicated tothe people who are the life blood and energy of theViking Flight Team. During the coming weeks thevarious technical groups and their personnel will be spot­lighted, and their contribution to the overall missionoperations program will be recognized. It is my hopeyou will enjoy meeting the people who have madeViking the exciting and dynamic success that it is.

VIKING PARTNERS ...LANDERS ON MARS AND PEOPLE ON EARTH

How do you maintain a planetary Lander spacecraftduring its flight to and while operating on a planet 200million miles from Earth? It's a tough assignment, andone that has taken years to design and prepare for inpursuit of a successful landed mission on Mars. There hasnever been an unmanned spacecraft design as complex as

MISSION STATUS BULLETIN SUPPLEMENT

VIKING PROJECT OFFICELangley Research CenterHampton, Virginia

Recorded Mission Status (213) 354-7237

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miniaturized, weight-limited subsystems to fit the size/weight constraints of the total vehicle, and the sub­systems had to be frugal electrical consumers to meetindividual budgets of power allocated from the battery/nuclear-generator power supplies. The Landers' com­puters and communications systems had to be designedto incorporate an independent capability for maximumautomation and Orbiter compatibility while allowing forextensive Earth-based control when necessary ordesirable to resolve problems or improve the sciencepotential.

The adaptive aspect of Lander performance, for bothengineering safety and science flexibility, has providedthe dividend the nation and the world have been sharingin since July 20 when the Viking 1 Lander became thefirst spacecraft to operate successfully on the surface ofMars. The duplicate success of Viking 2 on September 3amplified the importance of the massive amount of workthat went into the design of the Lander system to makeit a working, compatible partner of the Viking FlightTeam here on planet Earth.

The L-PAG personnel, divided into a number ofspecific teams, compiise the lead element in the per­formance achievements of the Viking 1 and 2 Landers.Throughout the 400-million-mile flights to Mars theymonitored and checked out the encapsulated Landers'subsystems waiting quietly for the ultimate Mars land­ings. Software systems were verified and intense training I)

Lander leads Jerry Lewis (center), Al Nash (top right),Gary Knowles (lower center) and Dick Bender (right)meet with Marv Udevitz (lower left) to discuss the lossof the Lander relay stream during the Viking 2 landing.

Systems Analyst Gregor Smith studies a copy of theViking 2 Lander sequence as Lou Moyer looks on.

programs were run to prepare personnel for both theexpected and the unexpected events that would or mightoccur during the Mars missions. Finally, the "real thing"arrived. Pre-separation checkouts, predicts, performanceanalysis, uplink commanding and downlink evaluations,the inevitable problems and troubleshooting efforts,their resolutions, and - always - the systems monitor­ing; it all came and passed with a professional smooth­ness and efficiency that bespoke the hard work thatwent into the design and planning phases. Long prepara­tion years, followed by long mission hours, have beenrewarded with two successful Landers on Mars. L-PAGpeople can proudly remember the day they spoke asone - "Touchdown ... we have touchdown!" On July20, 1976, TH EY landed on Mars. 0

AT THE HEADOF THE LIST!

Rex Sjostrom (a Swedish name pronounced"Shoe - strom") has seen a lot of aerospace and a lot ofColorado since leaving the Minnesota farm and the one­room school that were the focal point of his youth. Rex,his wife Joan, and three of their four children - Ann,14; John, 12; and Sharon, 10 - enjoy the best of Colo­rado mountain living, skiing and fishing, on their smallranch near Castle Rock, Colorado. Another daughter,Sandy, is married and is a college student.

Rex first acquired a BS in Civil Engineering in 1952and then a Masters Degree in Electrical Engineering inC>

Rex Sjostrom (left), L-PAG chief, and Marv Udevitzmonitor and evaluate Viking 1 performance during theentry and landing sequence July 20. •

Left to right, Lander communications analysts JimBerry, Roy McGown, Herb Kowitz and Fred Staggs(standing) monitor Viking 2 communication data fortelemetry indications of touchdown during the period'when Lander relay data had been lost due to an Orbiterattitude control problem. •

1956. He joined Martin Marietta's Denver Division thatsame year, and worked on the Titan I, II & III programsand the Manned Orbital Laboratory (MOL) programbefore the pre-Viking Voyager study became an activepart of Martin Marietta's Denver Division business.

When the transition from Voyager to Viking occurredin 1969, Rex was a sol id part of the team. His responsi­bilities grew with the program, reflecting his engineeringcompetence and effectiveness in directing the effortsassigned to him. He moved from the telemetry data man­agement effort to become Electronics Manager for theLander system, and was later named as EngineeringManager for the program. Rex has been at JPL sinceMarch, 1975, when he became L-PAG chief and beganViking Flight Team training operations.

The L-PAG deputies are Neil Holmberg and CharlieGreen, both NASA employees from the LangleyResearch Center, Hampton, Virginia. They supplementRex's responsibilities as L-PAG chiefs during Landeroperations, and head up special anomaly teams whenproblems arise during the mission.

Downlink and Uplink responsibilities fall to MarvUdevitz and Parker Stafford, both from the Lander pro­gram at Martin Marietta in Denver. These responsibilitiescontend with the vital functions of commanding theLander during its computerized operations on Mars, andof analyzing and assuring the quality of its Mars-to-Earthcommunication link. 0

LANDER PERFORMANCEAND ANALYSIS GROUP PERSONNEL

The Lander Performance and Analysis Group (LPAG) andits secondary teams include the following personnel, with theirhome organizations indicated in parentheses. LPAG CentralResponsibility: Rex W. Sjostrom, Chief (MMCl; Charlie H.Green, Jr., Deputy Chief (LRC); Neil A. Holmberg, DeputyChief (LRC); Jack S. Chipman, LPAG Documentation (MMC);Ed J. Mueller, LPAG Administrative Assistant (MMC); DebbieCulpepper, Secretary (JPL, Contractorl.Lander Systems AnalysisTeam: Marv P. Udevitz, Team Leader (MMC); Richard A. Bender(LRC); Gary R. Knowles (MMCl; Jerry G. Lewis (MMC); AI C.Nash (MMC). Lander Systems Analysis Unit: Frank X. Pfenne­berger, Lead Analyst (MMCl; Ed L. Kinney (MMCl; Lou B.Moyer (MMC); Joe W. Radcliff (MMC); Gregor Smith (MMC);Rick C. Vargo (KSC, Intern). Lander Data Processing Unit:BiliAlbers, Lead Analyst (MMC); Tom Arnold (MMC); MickeyBramble (MMC); Candy Vallado (MMC). Lander Science Inter­face Unit: Roland L. Dupree, Lead Analyst (KSC). LanderTelemetry Analysis Unit: O. J. Moore, Lead Analyst (MMC);Mark Brown (MMC); Frank Lavac (MMC); Chet Seese (MMC);Ted Smith (MMC). Lander Communications Analysis Unit: RoyE. McGown, Lead Analyst (MMC); Jim Berry (MMC); HerbKowitz (LRC); Fred Staggs (LRC). Lander Power Analysis Unit:Walt Smeton, Lead Analyst (MMCl; Jerry Bruno (MMC); CliffRea (MMC); Walt Von Flue (ERDA); Jim Williamson (ERDA);Dick Russell (LRC). Lander Thermal Analysis Unit: BradHarmel, Lead Analyst (MMC); Mike Griffin (MMCI; Ed Hankison(LRC); Roy Kannady (MMC). Lander Guidance, Control andEntry Analysis Unit: Tony Fontana, Lead Analyst (LRC); MikeDoty (MMC); Mick Hall (LRC); Bob Ingoldby (MMC); HarryIrwin (TRW); Jim Jones (LRC); Bill Jones (LRC); Fred Michel(MMC); Dave Steele (MMC); Ken Villyard (MMC); Bill Preston(MMC). Lander Command and Sequencing Team: Parker S. Staf­ford, Team Leader (MMC); Milt Holt, Lead (LRC); Jary Kerekes,Lead (MMC); Frank Wilson, Lead (MMC); Bob York, Lead(MMC); Jack F. Meagher (LRC); AI Moore (MMC); Lew Ruben­stein (MMCl; Bob Buchan (LRC); Steve Howe (MMC); GerrieSnyder (MMCl; Paul Crissman (MMC); Sue Lowrie (MMC); CarlMabee (LRC); Ron Siovikoski (MMCl; William T. Davis (LRC);Larry W. Bolin (MMC); AI Britting, Jr. (MMC); Gene Robinett(MMCl; Gary Buehler (MMC); Pat DeMartine (MMCl; AIDunklee (MMC); Gene Shirley (MMC); Gerry Shults (MMC). 0

System Analyst Frank Pfenneberger (left) goes Oller acomputer printout with Lander Power Predict AnalystGene Robinett. •

L-PAG Chief Rex Sjostrom (center) and deputies CharlieGreen (left) and Neil Holmberg monitor the Viking 2~ndmg. ~