Project scientist Gerry Soffen called Israel Taback the "father of the Mars Viking Lander," parentage that Taback rejected with his usual wry wit.

"He thought I was because I was responsible for most of the atmosphere surrounding the lander," Taback said. "Remember, there were over 150 Martin (Marietta) people and over 150 Langley people involved -- all talented, outstanding people. It didn't need a father.

"More of a godfather."

That was a role Taback – who passed away on August 30 -- could play naturally and did, from days when Langley was the National Advisory Committee for Aeronautics laboratory and he helped shepherd the X-15's instrumentation through its supersonic flights.

He carried the role through the transition into NASA, when he was chief engineer of one of the first of the new agency's projects, the Lunar Orbiter, which still ranks among NASA's most successful missions. Five Lunar Orbiters circled the moon, three taking pictures of places where Apollo could land, two mapping 99 percent of the lunar surface.

Then Taback went on to become deputy project manager for Mars Viking, in charge of building the lander that provided information that has been used for more than 30 years and will be used when NASA sends astronauts there, scheduled 22 years hence.

"I had the extraordinary opportunity to work under Iz's leadership for more than a decade," said Tom Young, who eventually became director at Goddard Space Flight Center before becoming an aerospace industry executive. "It's hard to imagine what a special thing it is for a young engineer to have that opportunity. Iz is clearly the best systems engineer I've ever known."

Said Fil Cuddihy, who assisted Taback on the technical side of Mars Viking: "I think Iz was just a wise mentor to everybody who had the privilege of working with him. He taught us all."

Small and slight of stature, Taback could teach so well because he had a natural curiosity and the kind of amazing intellect that made him challenge himself by doing things like working out the value of "pi" to 19 decimal places – in his head. For the curious, it's 3.1415926535897932385.

"I never spent a day in eight years without learning something after talking to Iz," said Gus Guastaferro, who worked on the business side of Mars Viking before leaving Langley for private business. "It was like going to school.

"He would ask the question I wouldn't ask. He would say, 'Fundamentally, that doesn't make sense to me. Explain it to me again,' and I would say, 'I'm glad he asked that because I didn't have the courage to ask it.' I wouldn't want my group to think I didn't know."

As much as anything, it was Taback issuing a Socratic challenge.

"He knew the answer," Guastaferro said. "He wanted to see what you were made of. He was testing you, not in a cruel sense and not in an aggressive sense, but in a way of letting you pass muster so he could gain confidence in what you were trying to sell him."

If it was "no sale," well, Taback had ways of dealing with that, too.

"I hadn't been working with NASA long and we had an outside contractor come in and make a presentation to Iz," Cuddihy said. "Iz gently poked and probed, and the guy didn't pay any attention. He had an agenda that he was going to sell.

"Finally, Iz said, 'well, you may be right,' and the guy went on with his presentation. What he didn't know was 'well, you may be right' was Iz saying, 'I'm done with you.' "

No sale.

Norm Crabill, who worked with Taback on Lunar Orbiter and Mars Viking, talked of a Taback technique that disarmed some.

"When you had a product and you gave it to an engineer and they went off and did all of these big computer programs, Iz would say, 'let's see if this is right,' " Crabill remembered. "He would go to a blackboard, even without a slide rule, and he would get an approximate answer. 'Yeah, that's right,' he would say, because the engineer's answer agrees with his approximate answer."

Young remembers sessions with Taback and a blackboard.

"Iz taught us that when you have a difficult technical problem, you don't solve it with meetings," Young said. "You don't solve it with consultants. You solve it by going back to basic principles. When Iz Taback would pick up a piece of chalk and go to a blackboard and say, 'let's go back to basic principles,' it was like watching a great master at work."

What the engineers came to realize was that Taback could do some of the quick calculations because he had already queried them about their methods. It was part of his management style.

"It was 'management by walking around,' " Guastaferro said. "He would walk around the Viking office and say, 'what are you doing?' He'd look at your in-basket and see it piling up because that was the days before e-mail. He would grab it and throw it in the garbage. He would say, 'you don't need that. Get around and talk to the people.' "

The young engineers would, of course, retrieve the contents of their in-basket, but then they would walk over to somebody else, to talk through problems.

There was some question as to whether Taback ever became comfortable with a computer. A chalkboard or a pencil and paper was more to his liking.

When Taback passed away, he was working on a car rack for his new adult tricycle. Two pages of penciled notes, sketches and engineering formulas were worked out, an 88-year-old man seeming to punctuate a 66-year career of engineering with one more design.