Although it's traveled 11.6 billion miles to interstellar space, Voyager 1's software isn't as high-tech as you may think. In fact, it has less than 40 KB of memory. To put that in perspective, your 16 GB iPhone 5 has about 240,000 times the memory of a Voyager spacecraft.

NASA developed Voyager in the 1970s in a pre-computer era when scientists had to rely solely on pencil, paper, chalkboards and their own mathematical skills. While that seems unimaginable in a time when we hold decades' worth of computational power in our pockets, Voyager 1 is one of NASA's most successful missions, and project scientist Edward Stone says he wouldn't have changed a thing.

"It's amazing it's lasted as long as it has," Stone tells Mashable. "I don't know how we could have done things much better than they were done. I mean things do wear out, and we've had to switch to some of our backup systems, but fortunately we have backup systems. That was part of the wonderful design of Voyager."

That successful design is due, in part, to Jupiter. The team took a nine-month detour to check each circuit and part to ensure it could withstand the intense radiation it would face in the planet's challenging environment.

"That was sort of our life test," Stone says. "Having survived Jupiter, in a certain sense, meant we had designed a spacecraft with a very robust response to natural, slow degradation."

NASA engineers assemble the Voyager 1 spacecraft in the 1970s. Image: NASA

Thirty six years after launch, NASA has turned off some of Voyager 1's functions — some due to degradation, others simply because they're unusable in its current environment. For example, the team turned off Voyager 1's camera — which snapped the famous pale blue dot image — because it's too dark to capture a photo in interstellar space.

Scientists still receive faint (but exciting) data from Voyager 1 as it travels through an unexplored region of space. The spacecraft communicates back to Earth using a 22.4-Watt transmitter — the equivalent of a refrigerator light bulb. When those signals reach Earth — which takes about 17 hours traveling at the speed of light — they are about 0.2 billion-billionth of a Watt.

However, when it comes to battery life, Voyager 1 has a leg up on the iPhone (and just about any other consumer electronic, for that matter). The spacecraft has a plutonium power supply that boasts an 88-year half life, meaning we'll stay in touch for years.

"It's a very simple, long-lived source of energy, but eventually it will run out," Stone says. Unfortunately, Voyager 1 won't have a charger to plug in to when that time rolls around — between 2020 and 2025.

Mashable composite. Images: NASA, Mashable