Voyager Probes Aim For Interstellar Space, Four Decades Of Travel | WAMU 88.5 - American University Radio

NPR : News

Filed Under:

Voyager Probes Aim For Interstellar Space, Four Decades Of Travel

NASA is on the brink of putting a man-made craft into interstellar space for the first time, as Voyager 1 speeds toward the outer edge of our solar system. The Voyager program's chief scientist, Dr. Ed Stone, spoke with NPR's Steve Inskeep about that feat, and what it means for NASA.

But they also talked about how the two Voyager spacecraft are still running, 34 years after their launch. And as you might expect, our two ambassadors to the galaxy are sporting the finest technology of 1977, the year they were launched.

"The computers onboard this spacecraft — it's a totally automated spacecraft — the computers have 8,000 words of memory," Stone tells Steve.

Steve reacts by saying, "That's, well, nothing" — to which Stone replies, "Yes. It's nothing."

Today's smartphones are exponentially more powerful, a fact that has been remarked upon in recent years, as processing power reached new heights in size and efficiency.

The Voyager probes send their data back to Earth via a large dish antenna, which stays pointed at their home planet.

Voyager 1 and Voyager 2 are now about 11 and 9 billion miles from the sun, respectively. In total, here's how far the the two spacecraft have traveled since their launch, as of Dec. 9:

  • Voyager 1: 14,714,066,931 miles
  • Voyager 2: 14,061,424,348 miles

"We have a 23-watt transmitter, transmitting from 11 billion miles out," Stone says.

It's worth noting that that means the Voyagers' transmitters are about 8 times stronger than, once again, a cellphone.

But despite their now-humble technology, the probes require energy to operate — and they're running out of juice. They're powered by heat from the natural decay of plutonium-238, which is translated into electricity by thermocouples.

"Very simple, robust power supply," Stone says. "The radioactive decay half-life is 88 years. And that's one reason that the spacecraft are still working. Because we have a very long-life battery, if you like.

But that battery is running down, and the Voyager craft are losing power. NASA scientists believe they'll be able to get data from the two probes until some time after 2020.

"We do know that our power level drops by 4 watts every year," Stone says. "And so, we have to systematically turn things off, one at a time. By about the year 2020, we'll have to turn off one of the science instruments. And by 2025, we'll have to have all the science instruments off. And that will be the end of the mission."

If they hang on that long, the two probes will have been in service for 48 years.

For anyone wondering about where Voyager stands in comparison to the Pioneer program, Voyager 1 passed Pioneer 10 to become the most distant man-made object in space on Feb. 17, 1998.

Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.

WAMU 88.5

Art Beat With Lauren Landau, Oct. 1

Music from West Africa and photography from South East Asia come to the D.C. area.

NPR

From Kale To Pale Ale, A Love of Bitter May Be In Your Genes

Researchers have found a gene that affects how strongly you experience bitter flavors. And those who aren't as sensitive eat about 200 more servings of vegetables per year.
WAMU 88.5

Legal Limbo No More? Bill To Go Before D.C. Council Lays Out Ridesharing Rules

Cab drivers in D.C. have long complained that their app-based, ridesharing competition are unregulated. Now D.C. Council member Mary Cheh is introducing a bill that would address these concerns.

NPR

'Ello' Aims For A Return To Ad-Free Social Networking

Ello is the viral social network of the moment. Ad-free, invitation-only and with the option of anonymity, it's generating tons of chatter as the latest alternative to Facebook.

Leave a Comment

Help keep the conversation civil. Please refer to our Terms of Use and Code of Conduct before posting your comments.