Curiosity Landing: What's With All the Peanuts?

Peanuts, the legume and not the lovable 1960s comic strip, experienced a surge in popularity last week as the world watched engineers in NASA's Jet Propulsion Laboratory (JPL) eating handfuls for good luck during Curiosity’s landing on Mars.

It’s a long-standing tradition dating back to 1964. Just before Ranger 7 launched to the moon on July 28, mission manager Harris Schurmeier handed out peanuts to ease tensions. He figured chewing or playing with them on the table would give his team something else to focus on.

Up to that point the Ranger program had been a stunning disaster, and JPL was running out of chances to prove it could succeed in space. Everyone involved in the mission knew that if the mission failed, substantial personnel changes would follow.

JPL got into the lunar exploration game in 1959. After the Soviet Union got the moon first with its Luna program, NASA sought to match then surpass its adversary and assigned JPL a lunar exploration program, the Ranger program. Ranger was a simple design. An Atlas rocket would take the spacecraft into orbit then an Agena upper stage would send it to the moon.

After nearly a month of launch delays from power outages, fuel tank valve malfunctions, and spacecraft subsystem failures, the Ranger program kicked off with Ranger 1’s launch at 6:04 a.m. on Aug. 23, 1961. Spotty telemetry told engineers that the Agena had failed and that the spacecraft was stuck in a near Earth orbit. That the spacecraft was working well was a very dim silver lining.

Ranger 2 followed in Ranger 1’s footsteps on Nov. 18 at 3:12 a.m.. Telemetry thirty-two minutes after launch confirmed that the Agena’s second burn had again failed leaving Ranger 2 stranded in a near Earth orbit. This time, the spacecraft wasn’t working at all. It tumbled around the globe for twenty hours before going silent.

Ranger 3 carried a camera and it was the first mission designed to impact the moon. But problems dogged the flight almost immediately after it launched at 3:30 p.m. on Jan. 26, 1962. The Atlas’ engine burned longer than expected, putting the spacecraft on track to pass ahead of and below the Moon rather than impact its surface. It was too big an error to correct with the spacecraft’s engine. Engineers tried to turn the spacecraft around to get a picture the moon’s far side, but the pictures that came back were of empty space.

After three consecutive failures, the press was starting to publicly doubt that JPL could get to the moon. NASA was questioning management behind the Ranger program.

Ranger 4 launched at 3:50 p.m. on April 23. The Atlas and Agena both performed well but the spacecraft’s signal was fluctuating, signaling to engineers that it was tumbling. It was on track to collide with the moon right on target, but it was a dead spacecraft. Its central computer and sequencer had stopped.

Ranger 5 launched through overcast skies on Oct. 18, 1962, just before 1 p.m. The Atlas and Agena sent the spacecraft on a perfect trajectory towards the moon, but then data started coming back garbled. Ranger 5 had switched to battery power. It wasn’t long before the batteries were depleted, leaving the spacecraft tumbling towards the moon.

This fifth failure reshaped the Ranger program. The last four missions were canceled and those that remained, Rangers 6 through 9, would be dedicated to capturing close up images of the moon.

Ranger 6 launched towards the Sea of Tranquility at 10:49 a.m. on Thursday Jan. 30, 1964. The Atlas performed flawlessly and the Agena sent the spacecraft hurtling towards the moon. A mid-course correction trimmed the flight path and put Ranger 6 on a perfect course for its target. There was only one malfunction on this mission and it came from the onboard RCA TV camera. The signal had cut out early in the mission for 67 second. When the cameras turned on on Feb. 2, the signal was weak. The spacecraft didn’t manage to capture any images before crashing into the moon.

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This was the heritage leading up to Ranger 7. There was talk that JPL should be shut down, that a university-affiliated center couldn’t handle a rigorous spaceflight program. There were suggestions that the program had been sabotaged -- a worker found a small polyethylene bag with 14 screws and a lock washer in one of the sealed electronic modules in Ranger 7’s television subsystem.

Ranger 7’s target was the Sea of Clouds, a beautiful target with shadows coming from the Copernicus crater. After launch, telemetry told JPL that the spacecraft was perfectly healthy and on track for its target. Consensus in JPL at that point was that the mission had a 50-50 shot of success. The next morning, mission scientists sent a command for a mid-course correction; the spacecraft’s perfect execution convinced engineers that Ranger 7 had a 80-20 chance of success.

By 6:05 a.m. on Friday morning, July 31, JPL’s visitors’ gallery in the Space Flight Operations Facility was packed. Below and in front of them, flight controllers at consoles monitored Ranger 7's telemetry. It was 20 minutes before Ranger 7’s scheduled impact, and the onboard video cameras were on and starting to warm up. Ninety seconds later JPL got a strong signal from all six on board.

Then, at 6:25 a.m., the hum of Ranger 7's telemetry stopped abruptly. The spacecraft had impacted with the surface right on schedule, and it had sent back a series of stunning images. The silence in mission control and the visitors’ gallery was replaced by applause as they realized that NASA and the nation had captured the first closeup pictures of the moon's surface.

It was a fantastic success after the run of failures, and whether or not peanuts had anything to do with it, the tradition has been in place every since.

Analysis by Amy Shira Teitel
news.discovery.com