Music.
Voice of Neil Ross: In the summer of 1962 final preparations were underway for the first U.S. attempt to reach
Earth's nearest planetary neighbor.
Venus provided the best chance for a spacecraft to reach its destination.
The spacecraft, though, was not what JPL engineers had first planned on sending.
John Casani: Mariner was to be a new design...really a second generation spacecraft...that was specifically
designed to go to Mars and to Venus.
But, the design was not far enough along for it to be used for the Venus '62 opportunity.
So we actually, took a Ranger...we called them Mariner 1 and Mariner 2 were the first two Mariner missions to
Venus but they were Ranger spacecraft. Not many people know that.
[Rocket sounds]
Ross: Mariner 1 blasted off the launch pad on July 22, 1962.
Mission Control: 20 seconds and going up very nicely.
Ross: At first all went according to plan, as the Atlas rocket accelerated through Mach 1, 2, and 3.
Mission Control: 30 seconds into programming. Over.
Ross: But then the Atlas began fishtailing and veering off course.
Mission Control: We're not on trajectory. This is Range Safety. Stand by. [Unintelligible]
Ross: Mariner was only seconds away from separating from the errant rocket when the Range Safety Officer
had no choice but to give the destruct command.
Mission Control: Destruct command. Repeat. Destruct command. [Unintelligible] apparently blew up.
Ross: Analysis showed that the cause of the rocket failure was a software error.
A single misplaced symbol of code had resulted in the loss of the first U.S. spacecraft
destined for another planet.
Bob Parks: It was offset a little bit by our knowledge that we had another one to go. You know, maybe we can
resurrect things here. And of course we put all energies into that.
[Rocket sounds]
Ross: With the software problem corrected, Mariner 2 lifted off and began its three and a half month journey
to Venus.
Parks: The Earth sensor, when we first turned it on up there and locked on the Earth, it was working fine
but it was working on a much lower level of sensitivity than we had designed into it.
As we got farther and farther away from Earth, we knew that if the sensitivity stayed like that, we knew we
wouldn't be able to stay locked on the Earth all the way to Venus.
Ross: As Mariner 2 raced away from Earth, the signal strength continued to lower. If the signal could not be
boosted, all communications would cease. There would be no science return. Only another mission failure.
Parks: And just a few days before, it would have stopped being able to track the signal strength jumped up to
where we designed it....and we were able to do the rest of the mission just fine with that Earth tracker.
Ross: Another pressing issue was keeping Mariner 2 on a proper course.
Tuesday afternoon it is decided to go ahead with the trajectory corrections. Goldstone engineers send roll,
pitch and velocity commands to the spacecraft. The motor is fine and shuts off on time. Now we must wait.
New tracking will determine if the flight path has been corrected.
Ross: For one hundred days, JPLers worked around the clock, steadying what was becoming an ever more
spacecraft.
One of the members of the team was a 22-year old flight controller who was both a pioneer in exploring the
planets and venturing into the male-dominated world of engineering.
Susan Stephenson: I found myself not only involved in the planning of the operations, but the actual conduct
conduct of the operations and before I knew it I was 22 and I had been assigned as one of several flight
controllers on Mariners 2.
I was good at that work. I was good at operations work. I had a shift of my own, usually midnight to eight in
morning! Women didn't have opportunities like that
and there were some number of people who were pretty sure that they shouldn't.
That flight was probably the largest experience in growing up a young woman could have. I got through it and
I was very proud of myself for getting through it. But from then on everything seemed easier.
Ross: In December, Mariner 2 was closing in fast on Venus. But it was in a precarious state. Portions of the
spacecraft were overheating. Several critical telemetry sensors had stopped working altogether. It was taking
all the energy the solar panels could produce to keep the spacecraft functioning.
On December 14, Mariner 2 made its closest approach to Venus, flying by at a distance of 20,000 miles.
In Pasadena, a steady stream of science data came pouring back as audible sounds throughout mission control.
[beeping]
Scientists were elated, although most of the results were more confirmations than new discoveries.
There was no on-board camera, so there were no pictures. There was also no sign of a magnetic field or a
radiation belt like Earth's. For a planet considered Earth's twin for its size and near proximity, Venus
revealed itself to be a hellish world filled with carbon dioxide - and where surface temperatures are
hot enough to melt lead.
[Music-'Stars and Stripes Forever']
If the science return was modest, the public reaction to the technical achievement was enormous.
For the first time, the United States could point to its first 'First' in the race for space.
'It is a proud time for the U.S.,' Time magazine proclaimed, 'No achievement by a Russian cosmonaut or U.S.
astronaut, no experiment made by any of the myriad other satellites that have been shot aloft, has taught man
nearly so much as the improbable voyage of Mariner 2.'
William Pickering found himself featured on the cover of Time. Pasadena honored the JPL Director by
naming him Grand Marshall of the Tournament of Roses Parade.
NASA arranged for Pickering and his management team to meet John Kennedy at the White House. In the Oval
Office they presented the President with a model of the spacecraft.
Twenty days after passing Venus, Mariner 2 transmitted half an hour of telemetry and then went silent.
Today the spacecraft is a mute piece of metal that endlessly circles the sun. But inside the spacecraft's
thermal blanket is a small American flag, secretly placed aboard against official wishes, as a patriotic act
to honor the very first 'first in space' for the United States.
NASA Jet Propulsion Laboratory, California Institute of Technology