A year ago, at a 35th anniversary celebration of Voyager 1's 1977 launch, Tom Armstrong was listening to some of the engineers and launch crew that worked to lob Voyager into space. They were talking about a moment shortly after launch when things could have gone very differently for the mission.
With fuel on Voyager's booster running low, they said there was about a two-second window to get the craft out of Earth's orbit. One second more, and it might have missed its flight path. And the trajectory of Armstrong's life might well have changed with Voyager's.
That's because so much of Armstrong's life has been tied to the space probe. He has watched space exploration history as it unfolded, from Voyager's design to the data analysis that led to September's announcement that Voyager had ventured past the heliosphere and is now traveling, at 38,000 miles per hour, through interstellar space.
Armstrong, a professor of physics at Kansas University from 1968 to 2003, helped design one of the key scientific instruments on the Voyager. Currently Armstrong, along with fellow scientist Jerry Manweiler, co-owns the Lawrence-based company Fundamental Technologies LLC.
The company analyzes reams of information from NASA satellite missions, as well as data from private companies and other organizations. Among the company's assignments from NASA: interpreting data that helped pinpoint Voyager's position in outer space.
Obviously, Voyager made it past the narrow window between Earth orbit and mission failure all those years ago. The modest car-sized craft has kept zooming through space after passing Jupiter and Saturn, sending back to Earth information about what it has found via a radio that operates on less power than the typical lightbulb.
That it's still chugging along amazes even Armstrong, "The damn thing's still working out there, after 35 years" Armstrong said.
Earlier this month, scientists announced that Voyager had become the first man-made object to enter interstellar space. The news came as no surprise to Armstrong. Scientists estimate that Voyager actually entered interstellar space in August 2012, according to NASA. It took more than a year of continued data collection before scientists, a famously cautious bunch, felt confident announcing that a technological and human milestone had been achieved.
During that time Armstrong had an intimate window into Voyager's travels. About a year ago he saw for himself signs of its exit from the heliosphere, a massive magnetic bubble created by the sun that envelopes the solar system.
"Voyager 1 was cruising along out there, 11 billion miles from the sun, and the responses of these instruments changed," Armstrong said. Some readings showed a sharp decline in the level of plasma, or ionized gas, around Voyager. Others shot up. The data coming to Armstrong suggested Voyager had entered someplace different, one suggestive of interstellar space, where the density of plasma is much higher than in the outer layer of the heliosphere.
Now we're there
It's easy to get caught up in the feat of rocket science and aerospace engineering that Voyager represents. But Armstrong notes that this month's revelation, not to mention the gobs of data coming from Voyager, could not be possible without the technological infrastructure here on Earth that follows and listens to the craft.
"If you can't listen to it, it might as well not be there," Armstrong said.
And the data coming back from Voyager would just be the meaningless babble of interstellar space if not for scientists such as Armstrong and his colleagues.
Armstrong said he'll keep listening to what Voyager has to say about outer space for "as long as there's data, as long as I can use a computer." Why would he do anything else, when every byte of data coming back from the probe carries the potential to change our understanding of nature?
"The role of our investigation of the galaxy up to this point, in all of human history, has been what's called remote sensing," he said. "Humans have never had communication with anything that they could prove was outside or beyond the solar system. Now we're there. Our generation is the first generation of humans for which this has even been thinkable."