Megalextoria

​Larry Zottarelli, the last original Voyager engineer still on the project, is retiring after a long and storied history at JPL. While there are still a few hands around who worked on the original project, now the job of keeping this now-interstellar spacecraft going will fall to someone else. And that someone needs to have some very specific skills.

Yes, it’s going to require coding, but it won’t be in Ruby on Rails or Python. Not C or C++. Go a little further back, to the assembly languages used in early computing. Know Cobol? Can you breeze through Fortran? Remember your Algol? Those fancy new languages from the late 1950s? Then you might be the person for the job.

“It was state of the art in 1975, but that’s basically 40 years old if you want to think of it that way,” Suzanne Dodd, program manager for the Voyager program, said in a phone interview. “Although, some people can program in assembly language and understand the intricacy of the spacecraft, most younger people can’t or really don’t want to.​”

As the new engineer, you have a few tasks ahead of you and about 64 kilobytes of memory to work with. The Voyager twins sport NASA’s earliest on-board computers, a step away from the sequencers used on projects like ISEE-3. A sequencer uses radio or audio tones to turn on an instrument but with an onboard computer, more functions can be automatic, which is especially helpful if your spacecraft is more than 12 billion miles away—17 hours by radio—and only certain antennas work with it. Voyager 2, now moving downward from the ecliptic of the solar system, can only be reached by the Canberra antenna of the Deep Space Network.

The last true software overhaul was in 1990, after the 1989 Neptune encounter and at the beginning of the interstellar mission. “​The flight software was basically completely re-written in order to have a spacecraft that could be nearly autonomous and continue sending back data to us even if we lost communication with it,” Dodd said. “It has a looping routine of activities that it does automatically on board and then we augment that with sequences that we send up every three months.​”

Both spacecrafts are “very healthy for senior citizens” Dodd says and they have enough power left to run for another decade, though beyond that the future is uncertain. To try and prolong their lives, a new engineer would have to help figure out a way to make a sort of “energy audit” from afar, check to see the energy requirements of remaining instruments, and help institute shutdown procedures that make the most of what’s left of the onboard energy.

“​[The original engineers] said, ‘This subsystem takes 3.2 watts of power.’ Well, it really took 3 watts, but they wanted to be conservative when they built the spacecraft,” Dodd says. “Now, we are at the point in the mission where we are trying to get rid of the margins and get the actual numbers.”

That’s when it’s time to turn back to old documents to figure out the logic behind some of the engineering decisions. Dodd says it’s easy to find the engineering decisions, but harder to find the reasoning. This means combing through secondary documents and correspondence hoping to find the solution, trying to get in another engineer’s head.

The last resort is picking those engineers’ brains directly. Many are retired, and are working on 40-year-old memories. Still, the small team working on Voyager today has a list of engineers and others on-hand to call in emergencies. Dodd herself has worked on the spacecraft off and on since 1984, just before the Uranus flyby.

Source: Why NASA Needs a Programmer Fluent In 60-Year-Old Languages

NASA’s Voyager 1 and Voyager 2 spacecraft are still going strong after nearly 37 years in space.

“Both spacecraft are still operating, still very healthy. I guess as healthy as we are at the table right now,” Suzanne Dodd, the Voyager project manager at NASA’s Jet Propulsion Laboratory (JPL) said, drawing a big laugh from the audience at the SpaceFest VI conference in Pasadena, California, on May 11.

Dodd was fresh out of college in 1985 when JPL recruited her as it geared up for Voyager 2’s upcoming encounter with Uranus. Nearly 30 years later, she is project manager of the Voyager Interstellar Mission under which the two spacecraft continue to explore the vast expanse of space beyond the planets.

Dodd was actually the youngster on the Voyager reunion panel. She was joined by Voyager Project Scientist Ed Stone and retired Voyager Mission Design Manager Charley Kohlhase, who were both on the project when it was in the planning stages in the early 1970s.

When the Voyagers were launched in 1977, NASA expected them to last four or five years, long enough to get them through close encounters with Jupiter and Saturn. But, they just kept going and going.

Voyager 2 went on to flybys of Uranus in 1986 and Neptune in 1989. It is now about 105 astronomical units from Earth. (One AU is the average distance between the Earth and sun, about 92 million miles.) Voyager 1, which flew out of the plane of the solar system after its 1980 flyby of Saturn, is in interstellar space at 127 AUs.

Stone and Kohlhase recalled their astonishment when an image showing two exploding volcanoes on Jupiter’s moon Io came into JPL late on a Friday afternoon in March 1979. The plumes went hundreds of miles above the surface, and the fallout covered an area the size of France.

“We had what I call a terracentric view, which was based on understanding Earth,” Stone said. “Before Voyager, the only known active volcanoes in the solar system were on Earth. Then we flew by Io, a little moon about the size of our moon, with 10 times the volcanic activity of Earth. And suddenly our terracentric extrapolation just was falling way short, and that was happening time after time after time.

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“The key thing about Voyager that was a revolution was it was a totally computer-controlled spacecraft that flies itself and has fault protection on board so that if something goes wrong, it takes action,” he said. “Because now it takes us 17 and a half hours to get a command up there, and it’s 17 and a half hours before we know if anything has happened.”

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Dodd says the Voyager mission continues to throw up challenges today. The spacecraft have 20-watt transmitters – the equivalent of a refrigerator light bulb – and signals are only 1 billionth of a billionth of a watt in strength by the time they reach Earth. JPL uses the powerful antennas of the Deep Space Network to communicate with the distant spacecraft.

“The engineering challenges are extremely unique to Voyager,” Dodd said. “You’re operating instruments below temperatures that we can’t even measure. Challenges of finding out if we turn on a component that’s next to a hydrazine line, would that hydrazine line freeze or not. We don’t know.

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“Looking forward, we expect to get 10 more years of scientific data out of the Voyager spacecraft,” Dodd said. “We basically turned off everything we can turn off to save power. Backup heaters are off, backup systems are off. We’re having some serious discussions about how to move forward, because we’re almost down to the scientific instruments now.”

After that, the spacecraft could continue on for another five to seven years sending engineering signals to Earth. Engineers are already in discussions with the Deep Space Network about what experiments could be conducted with those signals before the spacecraft fall silent.

Full article: http://www.space.com … r-system-legacy.html

NASA’s Voyager 1 probe has left the solar system, boldly going where no machine has gone before.

Thirty-six years after it rocketed away from Earth, the plutonium-powered spacecraft has escaped the sun’s influence and is now cruising 11 1/2 billion miles away in interstellar space, or the vast, cold emptiness between the stars, NASA said Thursday.

And just in case it encounters intelligent life out there, it is carrying a gold-plated, 1970s-era phonograph record with multicultural greetings from Earth, photos and songs, including Chuck Berry’s “Johnny B. Goode,” along with Beethoven, Bach, Mozart and Louis Armstrong.

Never before has a man-made object left the solar system as it is commonly understood.

“We made it,” said an ecstatic Ed Stone, the mission’s chief scientist, who waited decades for this moment.

NASA celebrated by playing the “Star Trek” theme at a news conference in Washington.

Voyager 1 actually made its exit more than a year ago, scientists said. But since there’s no “Welcome to Interstellar Space” sign out there, NASA waited for more evidence before concluding that the probe had in fact broken out of the hot plasma bubble surrounding the planets.

Voyager 1, which is about the size of a small car, is drifting in a part of the universe littered with the remnants of ancient star explosions.

It will study exotic particles and other phenomena and will radio the data back to Earth, where the Voyager team awaits the starship’s discoveries. It takes about 17 hours for its signal to reach Earth.

Full article: http://www.huffingto … ystem_n_3915762.html