The First Planetary Explorers

Fifty years ago today, we became interplanetary explorers. NASA’s 447-pound Mariner 2 probe zipped past Venus at a distance of 21,564 miles, sending back data on temperature and magnetic fields — the first successful visit to another planet.

In December 1962 that was quite an engineering triumph, and the spacecraft — modeled after the then-disaster-prone Ranger lunar probes — barely survived its ordeal at Venus. In fact, it’s still amazing that a small team at the Jet Propulsion Laboratory in Pasadena, who had never done any of this stuff before, was able to design, build, launch, and execute a successful planetary flyby, almost from scratch, in just a few months.

The project manager for Mariner 2 was Jack James, a Texas-born electrical engineer who had previously worked on missile programs at JPL. James wrote a memoir before he died in 2001; the following anecdotes from the Mariner 2 chapter are used here by permission of his son, Jack James.

In the rush to carry out the crash effort, errors were made. An error I actually enjoyed had to do with the quick rewriting of the Air Force contracts with . The young Air Force lieutenant who rewrote, negotiated, and had the contracts signed had been given verbal instructions. He apparently wasn’t too clear on the ultimate destination of this new mission. He had listed in the objectives of the contracts that they were to carry out a mission to Venice.

The flyby depended on the spacecraft’s ability to refine its course on the way to Venus, and one of James’ team doubted that the midcourse correction system could be ready in time to hit the summer 1962 launch window for Venus.

I consulted Dr. Homer Joe Stewart, who was serving in two posts: he was a key senior advisor to JPL, and at the same time a professor of aeronautics at Caltech. He was a man I thought a great deal of. I asked if we would be able to conduct a meaningful mission if we had no mid course correction system. In typical Homer Joe fashion—with a cigarette dangling from his lips and wearing a seersucker suit and tennis shoes—he went to a blackboard and started scribbling a lot of computations and drawings, most of which I did not follow. He concluded that the Atlas Agena injection accuracy alone would result in little chance of the spacecraft getting close enough to Venus to measure the magnetic fields or to make temperature measurements. He estimated that the mission would be primarily for national prestige by being the first spacecraft to go into the vicinity of a planet, but would not produce much in the way of scientific data.

James and another JPL manager, Bob Parks, then went to Washington and got NASA Headquarters’ permission — and the funding — to attempt the first American planetary mission.

Bob and I were staying in some old hotel I am certain was one that Lincoln had slept in. It had no air conditioning, but in those days hotel windows could be opened. To cool off a bit and celebrate, Bob and I, in our undershirts, took a bottle of Vodka, a bucket of ice, and some glasses, and walked up the staircase out onto the roof of the building. We gazed out at that great D.C. skyline and celebrated what we had accomplished and the uncertainties of what was about to begin.

In a 1987 interview to mark the 25th anniversary of Mariner 2, James recalled how the team worked long hours during the four months that their probe operated in interplanetary space.

I’d get called at all times of the night, you know, or I might be on travel. I was continually being called and given a report on things. My nerves had become so taut by this time, that I instructed everyone that would call me to start out with one of two sentences: “There is no problem,” or, “There is a problem.” I mean, just get it over with….Quite often, I got calls, “There is a serious problem.”

Mariner 2 survived, though, and returned data proving that Venus was oven-hot, and devoid of life (just as a young, not-yet-famous postdoc named Carl Sagan had predicted). The United States had beaten the Soviets (who had tried and failed to make a similar flyby) to Venus, and JPL had established itself as the world leader in planetary exploration, a position it still holds today.

As James wrote years later:

The science community was happy.
The NASA people were happy.
The newspaper people were happy.
The Campus was happy.
We were all happy.

Tony Reichhardt | READ MORE

Tony Reichhardt is a senior editor at Air & Space.