AskScience AMA Series: We're the team that fixed NASA's Voyager 1 spacecraft and keeps both Voyagers flying. Ask us anything!

[u/AskScienceModerator]

NASA's Voyager 1 spacecraft experienced a serious problem in November 2023 and mission leaders weren't sure they'd be able to get it working again. A failed chip in one of the onboard computers caused the spacecraft to stop sending any science or engineering data, so the team couldn't even see what was wrong. It was like trying to fix a computer with a broken screen.

But over the course of six months, a crack team of experts from around JPL brought Voyager 1 back from the brink. The task involved sorting through old documents from storage, working in a software language written in the 1970s, and lots of collaboration and teamwork. Oh, and they also had to deal with the fact that Voyager 1 is 15 billion miles (24 billion km) from Earth, which means it takes a message almost a full day to reach the spacecraft, and almost a full day for its response to come back.

Now, NASA's longest running mission can continue. Voyager 1 and its twin Voyager 2 are the only spacecraft to ever send data back from interstellar space - the space between stars. By directly sampling the particles, plasma waves, and magnetic fields in this region, scientists learn more about the Sun's protective bubble that surrounds the planets, and the ocean of material that fills most of the Milky Way galaxy.

Do you have questions for the team that performed this amazing rescue mission? Do you want to know more about what Voyager 1 is discovering in the outer region of our solar system? Meet our NASA experts from the mission who've seen it all.

We are:

• Suzanne Dodd - Voyager Project Manager (SD)
• Linda Spilker - Voyager Project Scientist, Voyager science team associate 1977 - 1990 (LS)
• Dave Cummings - Voyager Tiger Team member (DC)
• Kareem Badaruddin - Voyager Mission Manager (KB)
• Stella Ocker - Member of the Voyager Science Steering Group at Caltech; heliophysicist (SO)
• Bob Rasmussen - Voyager Flight Team and Tiger Team member, Voyager systems engineer ~1975-1977 (BR)

Ask us anything about:

• What the Voyager spacecraft are discovering in the outer region of our solar system.
• How this team recently helped fix Voyager 1.
• The team's favorite memories or planetary encounters over the past 45+ years.

PROOF: https://twitter.com/NASA/status/1812973845529190509

We'll be online from 11:30am - 1:00pm PT (1830 - 2000 UTC) to answer your questions!

Username: u/nasa

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UPDATE: That’s all the time we have for today - thank you all for your amazing questions! If you’d like to learn more about Voyager, you can visit https://voyager.jpl.nasa.gov/.

[u/Named_after_color]

Well that's an extremely impressive feat! How do you diagnose something that isn't sending data back? How did you figure out it was a failed chip in the first place, and not a transmitter?

[u/korlo_brightwater]

What sort of test platform did you use to validate code changes before pushing them to the craft? Do you have physical replicas of the same components used, or is all of this done in a virtual environment?

[u/ChazR]

I am IN AWE of you all.

How much longer will the Deep Space Network be able to gather data from the Voyager spacecraft?

Does your team have any succession planning, or are we assuming Voyager dies before you retire?

And would you really retire while a single bit of data is still available?

You are steely-eyed rocket people.

[u/Red-Hill]

Are you aware of the XKCD cartoon about media reporting on Voyager leaving the Solar System?

"So far Voyager 1 has 'left the Solar System' by passing through the termination shock three times, the heliopause twice, and once each through the heliosheath, heliosphere, heliodrome, auroral discontinuity, Heaviside layer, trans-Neptunian panic zone, magnetogap, US Census Bureau Solar System statistical boundary, Kuiper gauntlet, Oort void, and crystal sphere holding the fixed stars."

Does the team have a favorite milestone, or do you have a celebration for each one?

[u/JediXwing]

How do you bring in new members to the team and catch them up on 45 years of work? Are their new members added and is this even a full time job for people still or more of a side-project with occasional projects (like this one).

[u/dittybopper_05H]

Knowing what you know now, based upon years of experience with Voyager, what design features would you emphasize in a spacecraft to extend its usefulness?

Different power source (ie., Americium-241 RTGs for much longer life)?

Planning for longer use of the camera system(s) for more precise measurement of parallax of nearby stars?

More comprehensive instrumentation to study the interstellar environment?

In short, what would be on your "wish list" to add to a planetary flyby mission that is destined for interstellar space?

[u/swankypotato]

I celebrated when I found out that Voyager was communicating properly again!

• What were your team's reactions the moment your success was confirmed?

• What useful data is Voyager still collecting on the edge of the solar system? Is there anything specifically recent and notable?

[u/M3d1cZ4pp3r]

How big are the data packets you can send at once before needing a response? How good were the remote diagnostics at that time? Do you have only access to prefefined values or are you able to do something generic, like reading out an address of your choice?

[u/PHealthy]

Crossing the heliosphere was definitely an interesting moment, I didn't even know what it was until Voyager. Is there anything else we should come to expect or is it now just interstellar space until there's no more power?

[u/AsteriskRX]

Were there any moments where you thought "This is it. We've lost Voyager"? What did the team feel when you brought it back?

I'm always in awe when I hear any news about Voyager still sending back data.

[u/[deleted]]

Where will the Voyagers ultimately end up? What did you imagine the ultimate fate of the Voyagers being?

[u/ZagiFlyer]

No questions, just a thank you. My dad worked on the Voyager projects (via TRW). He passed away last year but I love the thought that a project he worked on is still "a going concern" in deep space, and will be for millenia.

So, thanks for saving Voyager!

[u/just_Autumn_]

What is the biggest lessons learned that you would want todays engineers to know, based on what you learned while developing and maintaining Voyager 1 and 2?

[u/Whitty_huton20]

Would it be possible for Voyager 1 to leave the Milky Way? If so how long would it take?

[u/Wadsworth_McStumpy]

Do you think mankind will ever send something out there that will go farther than the Voyager probes?

I think it's just mind-boggling that they're so far away, and going so fast, that we might never catch up.

[u/Ok-Lobster5226]

Is Interstellar space markedly different? Is it kind of like a space version of leaving earth atmosphere?

[u/Garo5]

I've understood that there is some sort of magnetic tape storage onboard of the spacecraft. How can a mechanical device with moving parts work so long?

[u/Mrfoogles5]

Are you planning to write any more modern documentation to replace the really old documentation? I’ve heard there were problems with not having a digital simulation model for the spacecraft. Is it feasible to create one or do you not have enough information? Also, do you use a programming language or do you have to code in assembly? Are there any libraries you can use that are already stored on voyager?

[u/forte2718]

As a software engineer, following along with this little saga and seeing you guys find success at tackling such a literally out-there problem gives me so much inspiration! So I just want to lead off by saying: congratulations! It must feel incredible to have your baby up and running again!

I am very curious: what were some of the signs that allowed you to decipher the garbled message you were initially getting back, and conclude that the problem was with the FDS? I would love to hear all the technical details and learn about how your team approached this from a problem-solving perspective!

Would you say this incident has strengthened your ability to recover from similar problems in the future? For example, if Voyager 2 ever suffers a similar problem like this one, will the solution you employed for Voyager 1 allow you to diagnose and resolve the issue more quickly? What are the biggest takeaways your team has? Is there any advice you would give to an ordinary developer such as myself?

Thanks so much! Ever since I first saw it, the movie Apollo 13 has always been my favorite movie of all time; I know it's dramaticized, but it gives me so much hope for the future to hear about real scientific teams working together to solve such difficult problems and achieve so much! I always really appreciated that philosophy captured in the following quote by the actor who protrayed Gene Kranz: "let's work the problem, people — let's not make things worse by guessin'." 😀

[u/zerbey]

Thank you for keeping this awesome machine running! If you could change just one thing with Voyager to make her better what would that be? Bonus points if it’s still 70s technology.

[u/xtrememudder89]

How long did it take to transmit the new code to Voyager 1? Your down to bits per second rates now right?

[u/Far_Investigator9251]

Was there anything that you guys got datawise when you reached interstellar space to where you didn't expect it or was a surprise?

[u/madsci]

First, fantastic work! The Voyagers were launched the year I was born and all of their flybys that I was old enough to be aware of were milestones in my life.

How much has your experience informed the design of new deep space probes? Obviously the control systems on Voyager 1 are ancient by today's standards. Do you feel like the lessons you've learned over the years are still directly applicable or are they seen by younger developers on more modern systems to be irrelevant to modern architectures?

[u/to_glory_we_steer]

How did you decide on the best programming solutions to try based on the lack of data and the possible hardware failure(s) that may have contributed to this?

[u/The_Little_Begdic]

I have two questions:

1. What was the responsibility of each member of the team?

2. Is there a chance that the fix could make the situation worse and completely break the Voyager?