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Worlds of Wonder

Season 1Nov 13, 2018

Technology can take you to unexpected places. The MarCO cubesats, flying towards Mars with InSight, are breaking new ground on how far these small satellites can go.

On a Mission podcast cover art

[0:01](Teddy Ruxpin song)

“Come dream with me tonight…”

[0:06] Narrator: In 1985, the talking teddy bear Teddy Ruxpin took the world by storm.

[0:11](Teddy Ruxpin audio)

My name is Teddy Ruxpin. Can you and I be friends?”

On a Mission podcast cover art

[0:15] Narrator:Teddy Ruxpin had a cassette tape player in his back. The cassettes made for the toy were special, because while the left track of the tape held the audio recording, the right track contained data commands to move Teddy’s mouth and eyes.

[0:28]Teddy Ruxpin commercial)

Commercial voiceover: “All he does is tell stories about friendship, caring, sharing. And he goes on adventures, where the only things he captures is a child’s imagination.”

Teddy Ruxpin: “We’re going to have lots of good times…”

[0:45] Narrator:This animatronic toy was seen as a marvel, and made a fortune for the manufacturer, Worlds of Wonder.

Teddy Ruxpin’s inventor, Ken Forsse, had been working on the toy’s concept long before it became a success. In the late 1950s, it was going to be a puppet. And instead of a teddy bear, it was going to be a monkey, named Simeon Greep, in honor of NASA’s space program. At the time, NASA was sending monkeys into space to see how they tolerated spaceflight before launching the first human astronauts.

[1:12](Teddy Ruxpin song)

“Let’s go to far-off places, and search for treasures bright…”

[1:20] Narrator:The success of Teddy Ruxpin was short-lived. Competing toy makers put out their own talking dolls, and when the stock market crashed in 1987, Worlds of Wonder went bankrupt and sold off their assets.

Around the same time, NASA was putting together a mission to Mars, and the group in charge of building its camera needed nearly two thousand computer chips. The rumor goes that they purchased AT&T computer memory chips originally intended for Teddy Ruxpin dolls.

[1:47](Teddy Ruxpin story, Airship”)

“You do understand the basics of aerodynamics, don’t you?” “Huh?”

[1:52](intro music)

[2:23] Narrator:We’re “On a Mission,” a podcast of NASA’s Jet Propulsion Laboratory in Pasadena, California. I’m Leslie Mullen, and this season we’ve been following the InSight spacecraft on its journey to Mars.

This episode is about how technology can take you to unexpected places. How something invented for one purpose can often end up being used for something quite different. There’s a lot more to that Teddy Ruxpin story, but I’ll tell you about it at the end of this episode.

An example of an unexpected use of technology for the InSight mission is a pair of small satellites. Bruce Banerdt, lead scientist on InSight, explains:

[2:58] Bruce Banerdt: There’s a technology demonstration called MarCO, which stands for Mars Cube One, and that’s a pair of CubeSats, which are little tiny satellites. They’re about the size of a briefcase, and they’re going to fly along with us to Mars.

[3:11] Narrator:NASA often sends new technologies along with space missions, just to see how they fare. For InSight, the MarCO technology demonstration is an add-on: the mission doesn’t rely on these CubeSats. The point is to piggyback on a more standard mission to test out how new technology performs in the harsh environment of outer space. Tech demos like MarCO are like a space engineer’s version of play.

[3:35] Bruce Banerdt:Compared to a big spacecraft like InSight, it’s almost like a garage project. Just a handful of scientists and engineers building these things in their own little laboratory. It’s a way to get relatively cheap access to space.

[3:47] Narrator:For MarCO, the big test is to see how far these small satellites can go.

[3:51] Bruce Banerdt:We already have hundreds of CubeSats going into orbit around the Earth, and we’re trying to sort of stretch that into interplanetary space, and so this is our first attempt to see how that’s going to work.

[4:02] Narrator:MarCO launched on the same rocket as the InSight lander. InSight was on the front of the rocket, while the two MarCO satellites were in the back.

[4:09] Bruce Banerdt:They’re actually in a little sort of suitcase container at the backend, so they kind of fly in “luggage.” And after we separate from the rocket, they actually push off to each side of our trajectory, and we fly to Mars, not separated very much, but they fly by themselves. They have their own propulsion system. They have their own battery system and power system, and they have some radios. And if they do work well, and if they go all the way to Mars, they’ll actually be able to relay the radio signal from InSight as it’s landing through the atmosphere of Mars, and give us possibly one of the first signals that we’re getting back from InSight.

[4:45] Narrator:Mars landers can talk directly to Earth, but the amount of information they can send that way is extremely limited. The bulk of their signals are instead sent up to satellites orbiting in the Martian sky above. Those satellites grab the lander’s signals and then toss them to us. Think of it as a space-age game of baseball.

[5:03](baseball game announcer, applause)

[5:10] Narrator:If InSight is the pitcher, then MarCO will be up at bat just as InSight enters the Martian atmosphere. Radio satellite dishes on Earth are the players on the field, waiting to catch the ball.

If MarCO works, we’ll get the information about InSight’s landing on Mars right as it’s happening.

But if MarCO swings and misses, it’s OK: we’ll get that baseball of data a few hours later from the designated catcher, the Mars Reconnaissance Orbiter. This satellite orbiting Mars will be setting on the horizon as InSight lands, so we’d have to wait until it swings back around the planet before it can toss us the ball.

[5:44](Baseball crowd sings “Take Me Out to the Ball Game”)
“…it’s one, two, three strikes you’re out at the old ball game!”

[5:55] Narrator:CubeSats are simple metal boxes with humble origins. First launched in the early 2000s, those CubeSats were school projects. Here’s Andy Klesh, chief engineer for MarCO:

[6:05] Andy Klesh: Originally, they started as a way to get students involved in space exploration. Take extra mass that was available on the launch vehicle, put it in a box, so that we had a standardized payload, and the students could build up different experiments, prove out technology, show that they could understand the space environment. And eventually, they’ve actually gone beyond that to do commercial opportunities with these, provide real science missions around the Earth. Well, in the 2010’s, 2011, we started to ask, “What can we do with these small platforms away from Earth to explore the broader solar system area?”

[6:41] Narrator: CubeSats that orbit Earth can use our planet’s magnetic field to keep themselves orientated. They’re small enough and light enough that that little push is all they need. But for CubeSats going beyond Earth, engineers had to come up with a propulsion system.

Propulsion systems work in space due to Newton’s Third Law of Motion: every action produces an equal and opposite reaction. The backward thrust of exhaust pushes the spacecraft forward.

Cody Colley is the Mission Manager for MarCO:

[7:11] Cody Colley:No one had made a propulsion system that small for that kind of dedicated purpose. Vacco, which makes valves for the biggest of spacecrafts, started building these cold gas propulsion systems, and that’s what we ended up flying, is a cold gas system. And the really cool thing about our propellant is it’s actually fire extinguisher propellant. It’s the same liquid in your common fire extinguisher.

We have one extra step there where if we just fired it just like a fire extinguisher, it’d be gone all at once and we wouldn’t be able very precisely control our trajectory. So we send it to a staging area where it goes down to a lower pressure. If you were to see it it’s like a little tiny puff. Instead of this big explosive thing – well, not explosive, hopefully – but a fire extinguisher going off is a little bit more dramatic than what you would see out of a CubeSat firing its system.

[8:01] Narrator:A fire extinguisher has essentially two components: a substance for fighting fire, and a propellant that makes that fire-fighting substance come out when you press the handle. Because the propellant is stored at high pressure, fire extinguishers canisters are made of strong metal to prevent them from exploding.

[8:18] Cody Colley:One of the key things about the MarCO design in particular to mitigate even that low pressure from ever becoming a problem is that the propulsion system would leak before it ever burst. So if we ever had a high pressure event, it would be a sad day for us, it would leak all of its propellant, but it would not blow up in the traditional sense. And that’s important. (laughs) Our number one requirement on MarCO out the door is: do no harm.

[8:41] Narrator: The fire-extinguisher propulsion system inspired nicknames for the two CubeSats. Here’s Andy Klesh again:

[8:47] Andy Klesh:Wall-E and EVE are really our nicknames for the two MarCO spacecraft. Officially, they are named MarCO-A and MarCO-B. And as you know from the Disney movie, Wall-E learns how to fly in space using this fire extinguisher, just as we’re learning how to fly these CubeSats out to Mars. So the team kind of picked up the names, and MarCO-B is officially Wall-E, and MarCO-A is EVE.

[9:06] Narrator: In the movie, Wall-E flies wildly through space as he learns to propel himself with the fire extinguisher. In a bit of serendipity with the movie, MarCO’s Wall-E started to flounder in its flight when its propulsion system developed a leak. Cody Colley explains:

[9:21] Cody Colley: One of the scariest things about the first observation of the leak was we noticed it, and then we had the end of our scheduled contact. We can’t have the radio on forever. We’re a small spacecraft, so the power involved with keeping the radio on is sort of a non-starter. So the spacecraft is set to turn off at a certain time. So we got messages down from Wall-E saying, “Yeah, I’m leaking; I’m leaking; I’m leaking; I’ve got to go now; I’ll talk to you in eight hours.” That kind of situation is definitely sort of – it takes you by surprise. It’s like, “Oh, man.”

One of the things that made the situation a little bit more tense is that what we do is we schedule contacts for the spacecraft, and then if we don’t give it new times to wake up, it goes into what’s called its “safe mode.” This was five days into the mission. It’s kind of a hit in the gut to have to think about, –”OK, the spacecraft is going to do basically the bare minimum to make sure that it’s surviving and we have to make the most of that.” It changes data rates; it starts using different antennas as it’s saying, “Hey, I haven’t heard from you. I need to hear from you. I’m going to do everything I can to hear from you.” So we have to try out different things to find out how is the spacecraft pointed; what antennas is it using? But that was one reality that we were facing on that day was if we didn’t get commands into the spacecraft, to take back the reins and tell it, “Hey you’re going to wake up on Tuesday, Wednesday, Thursday.” Then we would have gone into this safe mode pattern where every eight hours, the spacecraft turns on, but with a different antenna. And because we had the leak we wanted to be able to get in and do things about it. And so we really didn’t want to go into safe mode.

So that next contact was definitely nerve-wracking. You send commands before you see that the radio signal’s there. So you’re sending these quote-unquote “in the blind.” So you’re really worried about whether or not these commands are actually going to do anything. But lo and behold for us, we were incredibly lucky. It was a very happy moment: we saw the spacecraft come back and talk to us. From day one: seeing a leak; day two: the leak has changed, we were able to actually start making assumptions about the behavior and then make decisions about what made sense to do next.

There was a subset of people at a whiteboard trying to figure out what is the best way forward. What are all the things that we could try, coming up with that solution. And so it’s definitely like 48 hours of almost feeling like you’re locked in a room. (laughs) Which takes a toll.

We really quickly realized, “We’re going to have to live with this leak all the way to Mars.” It became a question of, “What do we do to use the least amount of propellant to give us the best case likelihood that we were going to get to Mars?”

Sort of counterintuitively, what we ended up doing is telling the propulsion system to turn on every hour and dump the contents of that staging area that I told you about. If you let the leak that we knew about – the leak between the tank and that staging area – develop, then what ends up happening is there’s high pressure in that staging area that then is just venting out in space, and high pressure is bad. High pressure means that you have lots of torques on the spacecraft. It means that you’re sending lots of propellant overboard, and propellant’s valuable. On paper it doesn’t necessarily make sense, but in practice it does, is actually tell the propulsion system, “Get rid of everything in your staging area every hour.” And what that does is maintains that staging area at a very low pressure all the time. So that the effect on the trajectory is really small. The effect on the amount of propellant that we’re sending overboard is really small. And the spacecraft’s able to point without really noticing that these, what are called “blow downs,” are occurring.

[12:57](WALL-E movie clip)



[13:01] Cody Colley:What we do ultimately is – in order to keep Wall-E and EVE in the right spot relative to each other – is Wall-E will do a blow down in one direction, and do that for a couple of days, and then he’ll flip that by 180 and do it in the opposite direction. He’s doing acrobatics on the way to Mars. He’s changing which direction he’s firing his thrusters in. It sounds kind of wild and punchy, but that has the net effect of we sort of we go away from where we’re supposed to be and then we come back. Sometimes we overshoot, but ultimately we come back to where we are supposed to be.

If you watch that movie, the similarities between MarCO and Wall-E are just way too many. (laughs) I always tell people that Wall-E has always been trying to impress EVE, and (sigh) that’s what he decided to give us was a leak.

[13:51](WALL-E movie clip)



[13:55] Narrator:Although MarCO-B is leaking propellant, Andy Klesh says the CubeSats have received an unexpected boost from the Sun.

[14:02] Andy Klesh:One of our best surprises along the way was that when we open up the high-gain antenna, we’re so light that we’re essentially sailing on the solar wind. We have a finite amount of propellant that we can use, and eventually, we’re going to run out. So we want to minimize how much we’re using, and we’re finding by tacking, with respect to the solar wind, that we don’t have to use it as often, which essentially gives us more propellant for use later in the mission.

[14:24] Narrator:The propulsion system was just one of many challenges in getting the MarCO project off the ground.

[14:30] Andy Klesh:One of the things that we’ve noticed about the MarCO technology is that it’s not necessarily as easy as everybody thinks it is. It is a smaller package, but that also means it’s much more dense. Compared to a normal spacecraft, we’re almost twice as dense. We’ve crammed that much more stuff on board. And because we’re so dense and so small, getting the connections in place are very difficult. We have a much smaller team and a much lower budget, and so we’re having to find creative solutions in order to still perform all these complex maneuvers and operations to get us out to Mars. So we might be smaller, but we’re certainly not less complex.

[15:07] Narrator:The MarCO team also had much less time than usual to pull together their mission.

[15:12] Andy Klesh:I was pulled into the Director of Solar System Exploration’s office, at the time, and he said, “We’ve decided to do this mission. We’d like you to be Chief Engineer. You have three days to put together a team. You’re presenting to the Executive Council on Monday. Go!” I immediately walked out of there and started calling people and really trying to pull together the best team that we could in order to make this mission happen.

One of the challenges of MarCO was actually, “Could we do this as a lab, to pull together a small spacecraft in that amount of time on there?” And with that, there are many choices that we had to make. “Could we put on advanced cameras on board, or would we just put on the best that we could at that time?” We now have commercial cameras on board that we are able to take some images, but that was not always a sure thing along the way and was the first thing that would be removed. We are hopeful that we might be able to take some images of Mars. We have been able to take a few images of Earth on the way out, but just the fact that we were able to image Earth from a CubeSat, millions of kilometers away, has been a fantastic early mission achievement.

[16:12] Narrator: If the MarCOs are successful, Cody says that could open up the field for more ambitious CubeSat projects.

[16:19] Cody Colley: It means that your access to space, the bar is way lower. You’re talking about decreasing the cost for a Mars mission by an order of magnitude. Granted the capability isn’t as large, but you can be far more tactical. That’s what CubeSats are really good at is: they can do a very specific thing. If we’re an order of magnitude cheaper, why not send an order of magnitude more? That’s where there are actually some applications where you’re talking about measuring the magnetic field of other planets, where you really want lots and lots of measurements taken. You don’t want to wait for your flagship mission to spend five years to measure it. It’s much more efficient to send a hundred small spacecraft in a swarm that can make these measurements. You can also have one semi-big spacecraft that’s sort of the mothership that receives all the data from all of its children and distributes that information. So there’s different architectures that now that we’re actually talking about sending hundreds of CubeSats, it’s really meaningful for us to actually start thinking about them. In the past they were, I would call it academic. I think we’re finally getting to the point where it’s not academic to talk about solutions like that.

[17:23] Narrator: So something that started out as a simple and cheap project for students could end up revolutionizing how we explore space.

[17:30] Cody Colley: MarCO is sort of this pathfinder mission to demonstrate years in advance that these technologies work. As the science capability for CubeSats has grown, we’ve inevitably looked skyward, almost like manifest destiny. We want to go other places.

[17:49] Narrator:As for whether Teddy Ruxpin computer chips flew to Mars, I tried to track down whether the rumor is true. I contacted the Mars Orbital Camera manufacturer, conducted research with a JPL historian, and spoke to people who had been working on the missions that the camera flew on: Mars Observer and Mars Global Surveyor. Everyone had heard the rumor, but no one could confirm it. The chips hadn’t been purchased directly from the manufacturer, Worlds of Wonder, but from layers of vendors who purchase and resell parts. I was told that the paper trail is so complex, it could take years to wade through it.

But I had one more avenue of investigation: the ID number on the AT&T chips that were used in the Mars Orbital Camera. So I bought a circa 1985 Teddy Ruxpin doll that was being sold for parts, and with a little help from folks here at JPL, performed open-heart surgery. The heart of the doll in this case was his circuit board, and it was – appropriately – located in his chest. The circuit board had seven computer chips, but none of those chips were made by AT&T, and none of those chips were for memory. Instead, they were used for other tasks like managing power and voltage, or audio amplification.

The rumor, as far as I can tell, is wrong.

However, it’s still true that computer chips originally made for one product were repurposed for a camera sent to Mars. That product just isn’t a Teddy Ruxpin doll. As often happens with gossip, the details may have gotten jumbled through the telling. And as often happens in science, the hypothesis doesn’t give you the answer you expected, but instead opens up new questions. Perhaps someone out there has the answer to this mystery.

Next time, On a Mission:

[19:36] Farah Alibay:That was kind of investigative work, but we did actually go back through those tapes to see if anyone had come in between certain hours. You really do feel like you’re in a police department sometimes. (laughs)

[19:46] Narrator:If you like this podcast, please subscribe, rate us on your favorite podcast platform, and share us on Facebook, Instagram, and Twitter. We’re “On a Mission,” a podcast of NASA’s Jet Propulsion Laboratory.

(end music: finis)

[run time: 20:04]