This illustration shows the position of NASA's Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto.

In the News

The Voyager 2 spacecraft, launched in 1977, has reached interstellar space, a region beyond the heliosphere – the protective bubble of particles and magnetic fields created by the Sun – where the only other human-made object is its twin, Voyager 1.

The achievement means new opportunities for scientists to study this mysterious region. And for educators, it’s a chance to get students exploring the scale and anatomy of our solar system, plus the engineering and math required for such an epic journey.

How They Did It

Launched just 16 days apart, Voyager 1 and Voyager 2 were designed to take advantage of a rare alignment of the outer planets that only occurs once every 176 years. Their trajectory took them by the outer planets, where they captured never-before-seen images. They were also able to steal a little momentum from Jupiter and Saturn that helped send them on a path toward interstellar space. This “gravity assist” gave the spacecraft a velocity boost without expending any fuel. Though both spacecraft were destined for interstellar space, they followed slightly different trajectories.

Illustration of the trajectories of Voyager 1 and 2

An illustration of the trajectories of Voyager 1 and Voyager 2. Image credit: NASA/JPL-Caltech | + Expand image

Voyager 1 followed a path that enabled it to fly by Jupiter in 1979, discovering the gas giant’s rings. It continued on for a 1980 close encounter with Saturn’s moon Titan before a gravity assist from Saturn hurled it above the plane of the solar system and out toward interstellar space. After Voyager 2 visited Jupiter in 1979 and Saturn in 1981, it continued on to encounter Uranus in 1986, where it obtained another assist. Its last planetary visit before heading out of the solar system was Neptune in 1989, where the gas giant’s gravity sent the probe in a southward direction toward interstellar space. Since the end of its prime mission at Neptune, Voyager 2 has been using its onboard instruments to continue sensing the environment around it, communicating data back to scientists on Earth. It was this data that scientists used to determine Voyager 2 had entered interstellar space.

How We Know

Interstellar space, the region between the stars, is beyond the influence of the solar wind, charged particles emanating from the Sun, and before the influence of the stellar wind of another star. One hint that Voyager 2 was nearing interstellar space came in late August when the Cosmic Ray Subsystem, an instrument that measures cosmic rays coming from the Sun and galactic cosmic rays coming from outside our solar system, measured an increase in galactic cosmic rays hitting the spacecraft. Then on November 5, the instrument detected a sharp decrease in high energy particles from the Sun. That downward trend continued over the following weeks.

The data from the cosmic ray instrument provided strong evidence that Voyager 2 had entered interstellar space because its twin had returned similar data when it crossed the boundary of the heliosheath. But the most compelling evidence came from its Plasma Science Experiment – an instrument that had stopped working on Voyager 1 in 1980. Until recently, the space surrounding Voyager 2 was filled mostly with plasma flowing out from our Sun. This outflow, called the solar wind, creates a bubble, the heliosphere, that envelopes all the planets in our solar system. Voyager 2’s Plasma Science Experiment can detect the speed, density, temperature, pressure and flux of that solar wind. On the same day that the spacecraft’s cosmic ray instrument detected a steep decline in the number of solar energetic particles, the plasma science instrument observed a decline in the speed of the solar wind. Since that date, the plasma instrument has observed no solar wind flow in the environment around Voyager 2, which makes mission scientists confident the probe has entered interstellar space.

graph showing data from the cosmic ray and plasma science instruments on Voyager 2

This animated graph shows data returned from Voyager 2's cosmic ray and plasma science instruments, which provided the evidence that the spacecraft had entered interstellar space. Image credit: NASA/JPL-Caltech/GSFC | + Expand image

Though the spacecraft have left the heliosphere, Voyager 1 and Voyager 2 have not yet left the solar system, and won't be leaving anytime soon. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, a collection of small objects that are still under the influence of the Sun's gravity. The width of the Oort Cloud is not known precisely, but it is estimated to begin at about 1,000 astronomical units from the Sun and extend to about 100,000 AU. (One astronomical unit, or AU, is the distance from the Sun to Earth.) It will take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud and possibly 30,000 years to fly beyond it. By that time, both Voyager spacecraft will be completely out of the hydrazine fuel used to point them toward Earth (to send and receive data) and their power sources will have decayed beyond their usable lifetime.

Why It’s Important

Since the Voyager spacecraft launched more than 40 years ago, no other NASA missions have encountered as many planets (some of which had never been visited) and continued making science observations from such great distances. Other spacecraft, such as New Horizons and Pioneer 10 and 11, will eventually make it to interstellar space, but we will have no data from them to confirm their arrival or explore the region because their instruments already have or will have shut off by then.

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Interstellar space is a region that’s still mysterious because until 2012, when Voyager 1 arrived there, no spacecraft had visited it. Now, data from Voyager 2 will help add to scientists’ growing understanding of the region. Scientists are hoping to continue using Voyager 2’s plasma science instrument to study the properties of the ionized gases, or plasma, that exist in the interstellar medium by making direct measurements of the plasma density and temperature. This new data may shed more light on the evolution of our solar neighborhood and will most certainly provide a window into the exciting unexplored region of interstellar space, improving our understanding of space and our place in it.

As power wanes on Voyager 2, scientists will have to make tough choices about which instruments to keep turned on. Further complicating the situation is the freezing cold temperature at which the spacecraft is currently operating – perilously close to the freezing point of its hydrazine fuel. But for as long as both Voyager spacecraft are able to maintain power and communication, we will continue to learn about the uncharted territory of interstellar space.

Teach It

Use these standards-aligned lessons and related activities to get students doing math and science with a real-world (and space!) connection.

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TAGS: Teachers, Educators, Science, Engineering, Technology, Solar System, Voyager, Spacecraft, Educator Resources, Lessons, Activities

  • Ota Lutz
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Michelle Vo poses for a photo in front of a full-size model of the Curiosity Mars rover at JPL.

Michelle Vo poses for a photo in front of a full-size model of the Curiosity Mars rover at JPL.

Until she discovered game development, Michelle Vo’s daydreams were a problem. She couldn’t focus in her computer science classes. Her grades were dipping. She wondered whether she was cut out to be a programmer or for school at all. So she took a break to make something just for fun, a self-help game. And help her, it did. Now focusing on virtual and augmented reality, Vo is back at school, studying not just computer science, but also cognitive science, linguistics and digital humanities. It’s a lot, but to create a virtual world, she says one has to first understand how people navigate the real one. This summer, at NASA’s Jet Propulsion Laboratory, the UCLA student applied her talents to VR and AR experiences that help scientists explore a totally different world, Mars. While Vo’s tendency to daydream hasn’t gone away, she now knows how to use the distractions for good; she turns them into VR inspiration.

What are you working on at JPL?

I've been working on multiple things. I work on this project called OnSight, which just won NASA Software of the Year, which we're really excited about. It's an AR project. ...

[A hummingbird flies past us and Michelle stops to point it out.]

Sorry, just got distracted. This is me on a daily basis, just distracted by everything, which is kind of how I work. I get distracted so easily, and it always takes my full attention. So if I get distracted by my work, it holds all my attention. I found out this year I have ADHD, which probably explains why I struggled so much in school. Oh gosh, this is distracting from the interview. [Laughs.] No, this is good for visibility. I struggled a lot in school because I was always distracted by my own daydreams. ADHD is often undetected in girls, since it’s not so much exhibited as fidgeting but, for me at least, spacing out and daydreaming. It was always really hard for me to focus if I wasn’t engaged. Thankfully, I’ve finally found a career where I can actually utilize that skill. My daydreaming is how I come up with my VR design ideas, and I’m so glad I can use it to help others. Maybe I didn't perform too well in school, but hey, look where I am now!

That's so great that you were able to channel it in that way. How did you go from struggling in school to doing VR?

When I first tried on a VR headset, I was like, "This is the future. I need to do whatever I can to learn about this." I decided to study computer science, but it was such a huge struggle. Not a lot of people know this, but I was on academic probation for a while. I had a 1.8 GPA at one point, because I was too shy to ask for help. I would get distracted and, overall, I felt discouraged. So I stopped studying computer science for a little bit.

When I took a break from school, I decided I wanted to try making a game. I wanted to do something just for fun, and I was determined to fix my bad habits. So with some friends, I created a self-help game at AthenaHacks, a women’s hackathon. For 24 hours, I was just immersed in my work. I had never felt that way about anything in my life, where I was just zoned in, in my own world, doing the thing I love. And that's when I realized, I think it's game development. I think this is what I want.

So I spent the year teaching myself [game development], and I got a lot more comfortable using the Unity game engine. I knew I eventually wanted to be a VR developer, so I saved up and invested in myself to learn the skills at Make School’s VR Summer Academy. That smaller learning environment opened up the world for me. It boosted my confidence more than anything to have the support I needed. I was like, "Maybe my grades aren’t so great, but I know how to make VR." And the world needs VR right now.

So when I went back to my university, I thought, "I'll try again. I'm going to go back to computer science.” And so far so good. I'm into my fourth year at UCLA studying cognitive science, linguistics, computer science and digital humanities. It sounds like a lot, but they're all related in the sense that they're all connected to VR, because VR is mainly a study of the mind and how we perceive reality. It’s not so much about computer science; you really have to know more about humans to create good VR.

So I went from literally the worst student in the class to killing it at NASA. [Laughs.]

Sorry, ugh, that was a lot. Haha, I look at a bird and go off on a tangent. That's my life.

So going back to your JPL internship, how are you using your VR skills to help scientists and engineers?

Michelle Vo in the InSight testbed at JPL

Michelle Vo poses for a photo with InSight Testbed Lead, Marleen Sundgaard. Image courtesy Michelle Vo | + Expand image

I’m interning in the Ops Lab, and the project I've been working on primarily is called OnSight. OnSight uses Microsoft’s HoloLens [mixed-reality software] to simulate walking on Mars. Mars scientists use it to collaborate with each other. We had “Meet on Mars” this morning, actually. On certain days, Mars scientists will put on their headsets and hang out virtually on Mars. They see each other. They talk. They look at Mars rocks and take notes. It's based on images from the Curiosity Mars rover. We converted those images to 3-D models to create the virtual terrain, so through VR, we can simulate walking on Mars without being there.

For a few weeks, I worked on another project with the InSight Mars lander mission. We took the terrain model that's generated from images of [the landing site] and made it so the team could see that terrain on top of their testbed [at JPL] with a HoloLens. For them, that's important because they're trying to recreate the terrain to … Wait, I recorded this.

[Michelle quickly scans through the photo library on her phone and pulls up a video she recorded from JPL’s In-Situ Instruments Laboratory. Pranay Mishra, a testbed engineer for the InSight mission, stands in a simulated Mars landscape next to a working model of the lander and explains:]

“When InSight reaches Mars, we're going to get images of the terrain that we land on. The instruments will be deployed to that terrain, so we will want to practice those deployments in the testbed. One of the biggest things that affects our deployment ability is the terrain. If the terrain is tilted or there are rocks in certain spots, that all has a strong effect on our deployment accuracy. To practice it here, we want the terrain in the testbed to match the terrain on Mars. The only things we can view from Mars are the images that we get back [from the lander]. We want to put those into the HoloLens so that we can start terraforming, or “marsforming,” the testbed terrain to match the terrain on Mars. That way, we can maybe get a rough idea of what the deployment would look like on Mars by practicing it on Earth.”
Michelle Vo in the InSight testbed at JPL

Michelle Vo stands in the InSight testbed at JPL with testbed engineers Drew Penrod (left) and Pranay Mishra (right). Image courtesy Michelle Vo | + Expand image

› Learn more about how scientists and engineers are creating a version of InSight's Mars landing site on Earth

They already gave us photos of Mars, which they turned into a 3D model. I created an AR project, where you look through the HoloLens – looking at the real world – and the 3D model is superimposed on the testbed. So the [testbed team] will shovel through and shape the terrain to match what it’s like on Mars, at InSight’s landing site.

Did you know that this was an area that you could work in at JPL before interning here?

OnSight was a well known project in the VR/AR space, since it was the first project to use the Microsoft Hololens. I remember being excited to see a talk on the project at the VRLA conference. So when I finally got on board with the team, I was super excited. I also realized that there’s room for improvement, and that’s OK. That’s why I'm here as an intern; I can bring in a fresh look.

One of the things I did on this project was incorporate physical controllers. My critique when I first started was, "This is really hard to use." And if it's hard for me to use as a millenial, how is this going to be usable for people of all ages? I'm always thinking in terms of accessibility for everybody. Through lots of testing, I realized that people need to be touching things, physical things. That's what OnSight lacked, a physical controller. There were a lot of things that I experimented with, and eventually, it came down to a keyboard that allows you to manipulate the simulated Mars rovers. So now with OnSight, you can drive the [simulated] rovers around with a keyboard controller and possibly in the future, type notes within the application. Previously, you had to tap into the air to use an AR keyboard, and that's not intuitive. We still need to touch the physical world.

How has this project compared with other ones that you've done elsewhere?

Well, I was the only girl developer intern on the team. I’m always battling stereotypes wherever I go and usually on other projects, I'm fighting for my place and fighting to fit in. But at JPL, everyone’s here because they love what they do. People are secure in themselves, and they see me as an equal. They're like, "Michelle has good ideas. Let's bring her to the table." Right off the bat, I felt accepted and, for the first time ever, the imposter-syndrome voice went away. I felt like I could just be myself and actually have a voice to contribute. You know, I might be small, I might be the shortest one, but I'm mighty. It’s been such a positive and supportive environment. I've had an incredible internship and learned so much.

What has been the most unique experience that you've had at JPL?

Working in the Ops Lab has been such a unique experience. Every day, we’re tinkering with cutting-edge technology in AR and VR. I am so thankful to have my mentors, Victor Luo and Parker Abercrombie, who give me the support and guidance I need to grow and learn. Outside of the Ops Lab, I also had the unique opportunity to meet astronaut Kate Rubins and talk about VR with her. I had lunch with NASA Administrator Jim Bridenstine when he visited JPL. And working with the InSight mission and Marleen Sundgaard, the mission’s testbed lead, was especially cool. I can't believe I was able to use my skills for something the Mars InSight mission needed. Being able to say that is something I'm really proud of. And seeing how far I came, from knowing nothing to being here, makes me feel happy. If I can transform, anyone can do this too, if they choose to work hard, follow their own path and see it in themselves to take a risk.

What advice do you have for others looking to follow your path?

Listen to your gut. Your gut knows. It’s easy to feel discouraged. But trust me, you’re not alone. You’ve always got to stay optimistic about finding a solution. I've always been someone who has experimented with a lot of things, and I think learning is something you should definitely experiment with. If the classroom setting is not for you, try teaching yourself, try a bootcamp, try asking a friend – just any alternative. You just have to know how you learn best.

My biggest inspiration is the future. I think about it on a daily basis. The future is so cool. I know I have a very cheery, idealistic view on life, but I think, "What's wrong with that?" as long as you can bring it back to reality, which I think I’ve been able to do.

Speaking of that, what is your ultimate dream for your career and your future?

I was raised in the Bay Area, and I grew up in Santa Clara so the tech culture of Silicon Valley was inescapable. I love Silicon Valley, but we have our problems. We have a huge homelessness issue. I’ve always thought, “We have the brightest engineers and scientists doing the most amazing, crazy things, yet we still can't alleviate homelessness.” Everybody deserves a place to sleep and shower. People need to have their basic needs met. I’d love to see some sort of VR wellness center that could help people train for a job, overcome fears and treat mental health.

That's my idealistic dream, but back to present-day dreams: I'm actually doing a 180. I'm leaving tech for a little bit, and I’m taking Fall quarter off. I'll start back at UCLA in January, but I'm taking a leave to explore being an artist. I'm writing a science-fiction play about Vietnamese-American culture. I was inspired by my experience here at JPL. I feel really optimistic about the future of technology, which is funny because science fiction usually likes to depict tech as something crazy, like an apocalypse or the world crashing down. But I'm like, “Vietnamese people survived an actual war, and they’re still here.” For my parents and grandparents, their country as they knew it came crashing down on them when they were just about my age. They escaped Vietnam by boat and faced many hardships as immigrants who came to America penniless and without knowing English. For them to have survived all of that and sacrificed so much to make it possible for me to be here is incredible. I think it’s a testament to how, despite the worst things, there's always good that continues. I’m so grateful and thankful for my family. I wouldn’t be here living my dream without them, and I want to create a play about that.

It's funny. Before I used to be so shy, so shy. I used to be that one kid who would never talk to anybody. So it's kind of nice to see what happens when the introvert comes out of her shell. And this is what happens. All of this. [Laughs.]


Explore JPL’s summer and year-round internship programs and apply at: https://www.jpl.nasa.gov/edu/intern

The laboratory’s STEM internship and fellowship programs are managed by the JPL Education Office. Extending the NASA Office of Education’s reach, JPL Education seeks to create the next generation of scientists, engineers, technologists and space explorers by supporting educators and bringing the excitement of NASA missions and science to learners of all ages.

TAGS: Higher Education, College, Students, STEM, VR, AR, Technology, Mars, InSight, Curiosity

  • Kim Orr
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JPL Christopher Esquer-Rosas holds an origami version of the Starshade engineering model behind him.

Origami is going to space and Chris Esquer-Rosas is helping it get there. A computer engineering student at San Bernardino Valley College in Southern California, Esquer-Rosas used to do origami only as a hobby, but now he’s using it to build a giant sunflower-shaped structure that his team hopes will provide a new window into worlds beyond our solar system. Esquer-Rosas explains how he’s putting his origami skills to use and what got him folding in the first place.

What are you working on at JPL?

I’m working on Starshade, specifically the Petal Launch and Unfurler System.

What is starshade and what is it supposed to do?

Starshade is a proposal to fly a giant, sunflower-shaped shade in front of a space telescope, so we can directly image exoplanets, which are planets outside of our solar system. One of the big issues that we have is that we know exoplanets are there, but we can’t get the data we want about them because the stars that the planets are surrounding are too bright and they're basically blocking our view. So what Starshade is going to do is suppress or diffract sunlight while a telescope with all the science instruments directly images those exoplanets. It will probably be a little image, like one-by-one pixel, but with that one image, we can actually get a ton of data about these exoplanets – so carbon dioxide emissions, possibly water vapor, methane, gases and things like that.

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There's a lot of origami involved in building Starshade. How does it come into play?

When it unfurls in space, Starshade is supposed to be 36 meters (about 118 feet) in diameter, which is about the size of a baseball diamond, and it's supposed to be only 2.5 meters (about 8 feet) in diameter when it’s stowed for launch. We’re using origami concepts to make that possible. Origami involves a lot of math. A lot of people don't realize that. But what actually goes into it is lots of geometric shapes and angles that you have to account for. One of the first things that I started doing on Starshade was helping with the stow pattern. So starting out with one sheet, how do you fold it so you can stow it at a much smaller size? Do you want it to be taller or shorter? How many folds do you want? And then, how small do you want it to be? We developed a bunch of algorithms, so now all you have to do is input the specs, push enter, and a new pattern is created instead of having to refold things over and over and over again.

What are some of the challenges in getting that whole operation to work?

There are lots of challenges. The first challenge is making sure none of the petals gets nicked. [Starshade is shaped like a sunflower.] The petal edges are razor sharp and they are what allow the light to be diffracted so we can image the exoplanet. The curvature of the petals has to be within half-a-human-hair-width accuracy, so we have to make sure nothing happens to them. If any of them gets nicked, then now we have this giant bright spot in our images. We also have to make sure all the petals end up in the correct position once Starshade unfurls. And we have to make sure no light comes through any part of the Starshade itself.

Which of those challenges are you working on solving?

What I’m working on is making sure none of the petals touches each other. That's one of the big challenges. We have to find a way to slowly unwrap the petals so nothing interferes or touches any of the petal edges or the petal itself.

JPL Interns

Meet JPL Interns

Read stories from interns pushing the boundaries of space exploration and science at the leading center for robotic exploration of the solar system.

Tell me about your background in origami and how it brought you to JPL.

I've been doing origami since the fourth grade, when my teacher read us “Sadako and the Thousand Paper Cranes.” At the end of the book, it teaches you how to fold your own paper crane. After I folded it, I just had this instinct to want to unfold it to see what it looked like. It has this unique pattern. So I started measuring it, and I figured out that different angles give you different lengths for the wings and the legs. So I was like, ok, what if you rotate the entire crease pattern 45 degrees? Now you get these more beautiful wings and you get a different shape. Then, I started folding other people's designs and learning how to design my own origami. I loved origami so much that I started learning the math behind it. A friend of mine, Robert Salazar, had started at JPL, and he was also an origami guy. We've been friends since seventh grade. He started on Starshade and then, eventually, he was leaving and he told them about me. They interviewed me a few times and then they were like, OK, come in and help us out.

Before that, did you have any idea there was an application for origami in space exploration?

I knew there were applications for other things like airbags and deployable mirrors, but I didn't know that there were space applications. That's what blew my mind. I was like, origami is going to space now? This is amazing.

Are you studying something origami-related in school?

I'm actually studying computer engineering, so it's completely different.

Has interning with Starshade made you want to change your career path?

It's like this close, because I've wanted to be a computer engineer since fourth grade as well. But since working here, a lot of the mechanical stuff has been a big learning experience. I didn't know mechanical engineering existed, but now that I do, it's amazing.

How do you feel you're contributing to NASA/JPL missions and science?

I feel like I'm contributing because, right now, interns are on the front lines of testing out the hardware and making sure everything works. We're dealing with issues, trying to fix them, and coming up with ideas. I feel like we're actually contributing a lot to how this thing could eventually deploy in space.


Explore JPL’s summer and year-round internship programs and apply at: https://www.jpl.nasa.gov/edu/intern

The laboratory’s STEM internship and fellowship programs are managed by the JPL Education Office. Extending the NASA Office of Education’s reach, JPL Education seeks to create the next generation of scientists, engineers, technologists and space explorers by supporting educators and bringing the excitement of NASA missions and science to learners of all ages.

TAGS: Interns, Internships, College, Higher Education, Student Programs, Starshade, Origami, Exoplanets, Technology

  • Kim Orr
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Screen capture from the Exploring Mars With Scratch lesson from NASA/JPL Edu

Try this lesson from NASA/JPL Edu to get involved and bring the excitement of NASA Mars exploration to students:

TAGS: HourOfCode, Computer Science, Computer Science Education Week, Coding, Programming, Lessons, K-12, Classroom Activities, Mars Exploration, Technology

  • Lyle Tavernier
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