[NASA Gravity Assist] : Season 5

[Orionid]

Gravity Assist: Season 5 Trailer – What’s Your Gravity Assist?
Apr 9, 2021


Go behind the scenes at NASA with Chief Scientist Jim Green in the Gravity Assist podcast. We’ll talk to people who work in lots of different areas to make space missions and scientific investigations happen. How does someone become an astronaut, or an engineer working on the Ingenuity helicopter, or a science communicator? Everyone has a gravity assist – that person, place, thing, or event that inspired them to do what they’re doing now. New episodes will be released on Fridays. Check out the podcast at https://www.nasa.gov/gravityassist .

Source: https://www.nasa.gov/mediacast/gravity-assist-season-5-trailer-what-s-your-gravity-assist

1) Black Hole Mysteries, with Jeremy Schnittman (2) Apr 16, 2021
    https://www.forum.kosmonauta.net/index.php?topic=5163.msg180048#msg180048

2) Talking to Ingenuity and Other Space Robots, with Nacer Chahat Apr 23, 2021
    https://www.forum.kosmonauta.net/index.php?topic=5163.msg180573#msg180573

3) Breaking Barriers, with Dana Bolles (2) Apr 30, 2021
    https://www.forum.kosmonauta.net/index.php?topic=5163.msg181073#msg181073

4) Always an Astronaut, with Ken Bowersox (2) May 14, 2021
    https://www.forum.kosmonauta.net/index.php?topic=5163.msg181428#msg181428

[Orionid]

Jedna na 1000 gwiazd staje się czarną dziurą, czyli czeka Wszechświat dość czarna przyszłość.

But one in 1,000 stars becomes a black hole at the end of its life. And if you think about the fact that we have over 100 billion stars in the Milky Way, you do the math and you end up with over 100 million black holes floating around the Milky Way. And we've seen 40 of them. So that leaves 99,999,000 and change that we've never even detected, and they're just going to be sprinkled throughout the, the Milky Way, just like all the stars.

Gravity Assist: Black Hole Mysteries, with Jeremy Schnittman (1)
Apr 16, 2021


Explore how the extreme gravity of two orbiting supermassive black holes distorts our view. In this visualization, disks of bright, hot, churning gas encircle both black holes, shown in red and blue to better track the light source. The red disk orbits the larger black hole, which weighs 200 million times the mass of our Sun, while its smaller blue companion weighs half as much. Zooming into each black hole reveals multiple, increasingly warped images of its partner. Watch to learn more. Credits: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell

What is a black hole? How do we study them when we can’t see them? Astrophysicist Jeremy Schnittman from NASA’s Goddard Space Flight Center joins NASA Chief Scientist Jim Green for a fascinating conversation about the latest black hole research.

Jim Green: NASA’s celebrating black hole week. Let's talk to an expert that can tell us about these very strange and mysterious objects.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Dr. Jeremy Schnittman. And he is a research astrophysicist at NASA's Goddard Space Flight Center. He joins us here on Black Hole Week, when NASA is celebrating that very strange and mysterious object we call black holes. Welcome, Jeremy, to Gravity Assist.

Jeremy Schnittman: Thanks, Jim. It's great to be here.

Jim Green: Your NASA webpage states that you call yourself a “general purpose astrophysicist theorist.” What does that mean? And what do you do?

Jeremy Schnittman: Well, I think maybe it'll help to, to describe to the audience first what is an astrophysicist in the first place? Right? Almost sounds like a made-up job. Sometimes I think it is. It's such a great job. Not to compare myself, but I think really the first astrophysicist that we know of it was Isaac Newton. Right? He was an astrophysicist because he took the laws of physics that he could see on Earth, right, the famous one about the apple falling, he could measure gravity on Earth. And he applied it to the heavens, he applied it to astronomy. So that's how you get “astrophysicist.” You're taking what we know about physics from a laboratory or from theories that we develop here on Earth, and applying it to the entire universe. And so that's, that's what I do.

Jeremy Schnittman: Why do I call myself a “general purpose astrophysicist” — I guess it's because I'm not really expert in anything, but you know, try to dabble a little bit in everything. When it comes to black holes, they really are a great intersection of everything.

Jim Green: You're right, black holes requires all kinds of knowledge. So, what got you really interested in the topic of black holes?

Jeremy Schnittman: I guess it started with, you know, right the beginning of graduate school. I mean, everybody, we grew up learning about black holes a little bit in school, and everybody knows that they're really cool and mysterious objects. But when I got to graduate school, I started learning about, you know, what, what a black hole really is. What does it really mean to be a black hole? What does it really mean to study black holes?

Jim Green: What exactly is a black hole?

Jeremy Schnittman: Even amongst the experts, I think you could probably find a disagreement about whether a black hole is an object, or is it just a part of space? It, it obviously starts off as an object, it starts off, most of them, we believe start off as massive stars that burn up all of their fuel during their lifetime. When you have a star that's much bigger than the sun, it it burns this fuel much hotter, and much faster. And after just a few million years, as opposed to the sun, which is billions of years old. After just a few million years, you're done with your fuel.

Jeremy Schnittman: So there's no more heat holding the Sun up, and the gravity, there’s still all the gravity, you just don't have that hot gas and, and pressure holding the star up, the gravity is going to win. And it collapses into, into what we call a singularity. Which is like just an explosion of density, of energy, of mass, we're not really quite sure. I personally just think of it as a, as a hole in space right? They’re a nice round hole described by a lot of mathematical equations.

Jeremy Schnittman:You have this famous edge of the black hole we call the event horizon. And that's really where nothing, nothing can escape from not light, not particles. Nothing at all.

Jim Green: So if we can't see them, because the light is not allowed to leave this particular area, how do we really study them?

Jeremy Schnittman: There’s this kind of irony of black holes that are black and invisible. But they're also some of the brightest objects in the entire known universe. And the reason is, because when you tend to get too close to a black hole, if you're a planet or a star cloud of gas, you get whipped around into a really fast orbit going nearly the speed of light, heated up to millions of degrees and shining out in bright ultraviolet, X-ray, radio, just really bright, bright sources of light coming from not the black hole itself, but from the effect that it has on anyone who gets too close to it. So that's why, that's how we see them. That's how we study them. For the most part.

Jeremy: There are a couple other ways that you can study them, not through the material immediately around the black hole. Anything that is affected by gravity, we’ll be able to, to measure it and use it kind of indirectly to infer the properties of the black hole. So if you see a star in the middle of space, just moving around in a circle around nothing, that's a pretty good hint that there's something like a black hole right next to it.

Jim Green: Well, how close can you get to a black hole before you fall in?

Jeremy Schnittman: I guess this depends on your rocket ship. If you're just, you know, a run of the mill astronaut floating through space, you really want to keep your distance. You don't want to get anywhere within, you know, the strong, strong gravitational pull of a black hole, maybe 10s or 20s of times the black hole’s radius.

Jeremy Schnittman: If you have a really good rocket where you can fire your retro rockets and you know, kind of get down close and then pull away again, you can get up to about twice the black hole’s radius, what we call the Schwartzschild radius. And still escape if your rocket is, you know, can get you almost up to the speed of light. If you basically turn yourself into a photon going the speed of light, then you can get just up to the event horizon. But you better turn yourself perfectly around and head straight out again, before it's too late. Once you get past that, and there's no return.

Jim Green: Well, as you mentioned, some of the stars and produce supernova explosions are massive enough to become black holes. So we do see supernovae. We see them in other galaxies and even our own galaxy. So how far away is our closest black hole?

Jeremy: So of the of the black holes that, we've seen and observed in our own galaxy in the Milky Way. It's really not that many.

Jeremy Schnittman: But one in 1,000 stars becomes a black hole at the end of its life. And if you think about the fact that we have over 100 billion stars in the Milky Way, you do the math and you end up with over 100 million black holes floating around the Milky Way. And we've seen 40 of them. So that leaves 99,999,000 and change that we've never even detected, and they're just going to be sprinkled throughout the, the Milky Way, just like all the stars. And again, you do a little bit of math, and the chances are, that there's a black hole that we've never even seen within only, say, 25 light-years of the Earth. I mean, it doesn't pose any immediate risk. But I tell you, when whenever it happened, you know, billion years ago, when it went supernova, it would have been a pretty bright day out.

Jim Green: Yeah, no kidding.

Jeremy Schnittman: But if you had to bet, and you look up into the sky and you see a galaxy, I’d put pretty good money, that there's a black hole in it.

Jim Green: Okay, so, are there tiny black holes? How small can a black hole be?

Jeremy Schnittman: Ah, that's a good question. Since the only ones we really understand at all are these ones that come from collapsed stars. So those are kind of the smallest we've seen so far. But there's no real reason you can't form a smaller black hole. There's a famous effect, predicted by Stephen Hawking, about, well, appropriately enough, called Hawking radiation, where a black hole actually leaks out a little bit of radiation from the surface, due to complicated quantum mechanical effects that I can't claim to understand.

Jeremy Schnittman: But we, we know that we've never actually seen this in the lab or in space, but we know that if it exists, the smaller the black hole, the brighter the radiation, interestingly enough, so if you get too small, the black hole actually gives off a lot of radiation and then actually just evaporates and disappears in a in a big bang and flash of gamma rays.

Jeremy Schnittman: So, if you if you think about what, how small can you be it kind of is a question of how small can you be and still survive the Hawking radiation? It would be much, much smaller than the size of the Earth. And we haven't yet seen anything like that. But again, no reason they might not exist.

Jim Green: So do more massive galaxies have more massive black holes do you think?

Jeremy Schnittman: They do. There seems to be a pretty tight relationship as you get to be a bigger and bigger galaxy, or more specifically, a bigger and bigger bulge, right? Just that that center region of stars, they get bigger and bigger. I mean, we think of 4 million times the size of the Sun is mind bogglingly huge. But by galaxy standards, it's a, you know, it's a drop in the bucket. We've seen black holes that are a billion times the size of the Sun, or even larger.

Jeremy Schnittman: And, but, but kind of interestingly, as you get to the really big galaxies with the really big black hole holes, the, the actual density of stars in that center region seems to go down a little bit. It's what we call a core, it's almost like a blender has scoured out those middle regions of the galaxy. And, and that's kind of what we think happened is that the two galaxies merge, and they each had a black hole, the black holes fall in towards the center of the galaxy, they start whipping around each other, and just blend, you know, “Mix Master” throwing stars out left and right, and kind of clear out a little bubble in the center. And, and that's what we're seeing in some of these big galaxies.

Jim Green: Well, sometimes those two will merge. So what happens when we have two black holes merge?

Jeremy: So that is, that is the biggest brightest thing that ever happened in the universe, the merger of two black holes when they actually come together, give off something called gravitational waves. And those gravitational waves have energy just like electromagnetic waves, or ocean waves, or sound waves. The amount of energy that those things give off, actually, outshines the entire known universe, entire universe just from one pair of black holes for that, you know, five seconds, or even five hours depending on the size, how long it taking them to merge.

Jeremy Schnittman: Now, we can't see this because our eyes don't see gravitational waves. So it doesn't, it's not like a supernova where, you know, big bright blast in the sky. It's more like a, a sound, a bang, than a flash in the sky. So only very, very recently, were we able to make the ears on Earth that could hear the sound of the of the gravitational waves, these ripples in the very fabric of reality that go propagating throughout the entire universe.

Jim Green: Jeremy, what is LIGO? And how did it make those spectacular measurements of gravitational waves?

Jeremy Schnittman: LIGO, the Laser Interferometer Gravitational Wave Observatory, is actually two different observatories in the United States. One is located in Louisiana, and one is in Washington State. And it's been a big, massive project funded by the NSF. And there's another sister observatory called Virgo In Europe, that's also really leading the revolution in gravitational wave science.

Jeremy Schnittman: Gravitational waves are ripples in the fabric of space time. And one of the important things is, is it easy to picture ripples in space, right, like a piece of fabric stretching and shrinking. But it's also important to think of it as the ripples in time, right? So it actually changes the amount of time it takes for a laser beam or a particle of light to go a certain distance. So the way that LIGO measures this, it's very, really, really clever. It sends a race between two rays of light, and it kind of splits them with the mirror, and it sends one, one way in one the other way, and bounces off another mirror, which is actually miles away down a long tube, bounces the light back to the starting line and sees which, which light got there first. And from that you can tell, which, you know, kind of which leg of the race was a tiny bit shorter or a tiny bit longer due to this gravitational wave.

Jeremy Schnittman: And, you know, it sounds very simple and straightforward, but at the end of the day, we're talking about light that’s going over 4 kilometers, and then 4 kilometers back in the one, and one ray of light is beating the other one by a fraction of the radius of a proton.

Jim Green: Wow!

[Orionid]

Gravity Assist: Black Hole Mysteries, with Jeremy Schnittman (2)


Astrophysicist Jeremy Schnittman works at NASA’s Goddard Space Flight Center. Credits: NASA

Jeremy Schnittman: So it is no small task from a technological point of view to run this race, but they did it and we've been reaping the benefits ever since.

Jim Green: How excited were you? And what were you thinking about when you, when you heard about these results?

Jeremy Schnittman: I mean, it was it was really cool. I, I sometimes think of it as you know, when you have your when you have your first child, right? It's very exciting. But you know, it's not a huge surprise. I mean, you had nine months to somewhat prepare for it, you know, it's coming but still when it, when it finally happens, even though you've been working on it for years, in cases, it's still just a magical experience and it’s, you know, as a physicist working in in black holes and gravitational waves, it is also kind of, you know, like telling us, “Oh, you guys, you were right all along.” And you know, who doesn't like to hear that?

Jim Green: Well, you know, it really opens up a new horizon for us in terms of developing new telescopes or techniques to measure these gravitational waves. What are the particularly new telescopes or upcoming observations that you're excited about?

Jeremy Schnittman: Yes, so especially for the gravitational waves. When two black holes collide, they make gravitational waves. But like a bell or a, or tuning fork, right, different size, black holes make different types of waves, you can get a really, kind of, short, high-pitched sound or a very long, deep ripple going through, through space. So, like we've been talking about, we have these two different types of black holes, the ones about the size of the Sun, or a few times the size of the Sun. And those are the ones that we've detected the gravitational waves from with LIGO, which are these giant lasers on the surface of the Earth.

Jeremy Schnittman: To get the supermassive black holes, the gravitational waves from those, they're going to be at a much lower frequency. So to hear those, we actually need to build a detector in space. And that's one of the big projects that we here at NASA are working on, called LISA, the Laser Interferometer Space Antenna. And it's interesting, that it’s called an “antenna,” as opposed to an “observatory,” right. “Observatory,” you think of kind of like a telescope, you pointed out a star and you take a picture. An antenna, it's just going to be listening all the time to everything in space. And that's what we're going to use to hear these deep rumble waves from merging supermassive black holes throughout the universe.

Jim Green: So LISA is a fantastic European Space Agency project that NASA and several other agencies are really excited about. And it requires at least three spacecraft that look at each other with lasers. Do you think that's gonna really solve a lot of the next problems that we want to know about black holes?

Jeremy Schnittman: For sure, one of the biggest ones that we want to answer is, like we were saying before, where do these supermassive ones come from? I mean, it would, it would be like if, if living on Earth, you know, we knew of, you know, insects and dinosaurs, and nothing else. Like, how is that even possible. But if you look at the fossil record, you can kind of piece them all together, all the missing links in between. And we hope that LISA will help us kind of dig through the fossil record in real time. Because, you know, one of the great things about astronomy is you look at things far away, you see what they were looking like a long time ago. So by looking at the entire universe, which LISA will be able to do, you can see the evolution from really just a short time after the Big Bang all the way up to now.

Jim Green: So, you've been working on this, I don't know, at least a decade, maybe more, what's some of the most exciting results that have come out recently?

Jeremy Schnittman: So I think hands down the, the biggest recent discovery with, with black holes, I guess, since the LIGO era hit in 2015, was this very famous release of the Event Horizon Telescope image where they took an actual picture of a black hole, released just about two years ago in in April 2019, using this huge network of radio interferometers. And these are different interferometers than LIGO. But they're used to actually take a picture of a black hole so that they could zoom into this tiny, tiny, tiny space millions of light-years away, and actually see what the what the black hole looks like. Again, it's not, not the actual black hole, we're picturing the gas immediately around the black hole. But for all intents and purposes, that's the same thing. And we're really excited about seeing where, where we can go next with this type of technology.

Jim Green: Out of all the unknowns about black holes? What's the one question that you, Jeremy, would like to be the one to answer?

Jeremy Schnittman: It's kind of obscure. But one of the things that I, I actually made a prediction of in graduate school is that when you have two of these black holes orbiting around each other, and getting closer and closer and merging into a single black hole through gravitational waves, the spins of the black hole, kind of the way that they're oriented, should be aligned in a very specific way. So we haven't yet got enough data to prove that one way or another. But hopefully within the next few years with something like LIGO, we'll be able to identify this effect and maybe even proven an old prediction right. So that would be exciting. For me, personally, I don't know if anybody else would care.

Jim Green: Oh, I think that's fantastic. I would. I'll be on the lookout for that. That's wonderful.

Jim Green: Well, you know, Jeremy, I always like to ask my guests to tell me what was that event or person place or thing that got them so excited about becoming the scientists they are today? Now it’s very appropriate today in particular that I call that event a gravity assist. So Jeremy, what was your gravity assist?

Jeremy Schnittman: Yeah, I was, I was thinking about that, too, Jim, is you know, as gravity assist is the perfect name for our discussion today, because black holes are all about gravity. That being said, my, you know, my real foray into physics and real physics research, had nothing to do with gravity. It was when I was a junior in high school, I got to do a summer research program very fortunate and privileged to have been able to participate in that the University of Rochester and they have a giant laser lab where they use mega, megawatt mega-megawatt lasers to do nuclear fusion experiments.

Jeremy Schnittman: And I, you know, got to see firsthand what, what real physics research was, was like. It wasn't like homework. It was finding answers to problems that nobody had ever solved before. And it was just captivating and you know, never looked back. From then on, I just knew exactly that's this is what I wanted to do.

Jim Green: Yeah, that's fantastic. Well, Jeremy, thanks so much for joining me in this fascinating discussion about black holes.

Jeremy Schnittman: Oh, it was a pleasure. I always love talking about space and I love talking about black holes. Thank you.

Jim Green: Well, join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green and this is your Gravity Assist.

Last Updated: Apr 16, 2021
Editor: Gary Daines

Source: https://www.nasa.gov/mediacast/gravity-assist-black-hole-mysteries-with-jeremy-schnittman

[Orionid]

Gravity Assist: Talking to Ingenuity and Other Space Robots, with Nacer Chahat
Apr 23, 2021


The Ingenuity helicopter made history on April 19, 2021, with the first powered, controlled flight of an aircraft on another planet. How do engineers talk to a helicopter all the way out on Mars? How about other spacecraft? We’ll hear about it from Nacer Chahat of NASA’s Jet Propulsion Laboratory, who works on antenna and telecommunication systems for a variety of NASA missions. He chats with NASA’s Chief Scientist Jim Green in this episode of the Gravity Assist podcast.

Jim Green: NASA flies spacecraft all over the solar system, and orbits the Earth. How do we communicate with them when they're so far away? Let's find out from an expert.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Nacer Chahat, and he is the senior antenna and microwave engineer with NASA's Jet Propulsion Laboratory out in Pasadena, California. He has worked on one of the most important challenges for NASA and that is, in designing a spacecraft, how do you make it communicate back and forth with Earth? So welcome to Gravity Assist.

Nacer Chahat: Thank you for having me here.


Nacer Chahat of NASA's Jet Propulsion Laboratory with a model of the Ingenuity helicopter. Credits: NASA/JPL-Caltech

Jim Green: A lot of people are familiar with the idea of an antenna from a radio or TV set, for which they receive a signal. But when we look at a spacecraft, we see all kinds of different antennas. What's their main function?

Nacer Chahat: Yes, so, the principle is the same. However, every single spacecraft have different instruments, So, depending on the requirement, whether they are instruments or ­­communication, they come in different form, different aspects. So, most of the communication antennas will be the typical dishes that we see. So, those are the ones that you see the most often on spacecraft. But whenever we push the boundary of what we are trying to do, we have to come up with different innovative antenna solutions to address the needs of our scientists.

Jim Green: You know a lot of the antennas that you use, you use for what we call remote sensing. What's that really mean?

Nacer Chahat: So, remote sensing allows us to get something from afar and so we're using radio frequency to transmit pulses. These pulses are reflecting back from the surface of what we want to study, and then we're processing this data to make conclusions.

Jim Green: Yeah, that's everything from having the opportunity to bounce radio waves off surfaces to even penetrate those radio waves into surfaces like, like the ice caps or even the Sahara Desert.

Nacer Chahat Yeah, and that also allows us to get images of things we cannot see. So, for example if the weather is bad and Earth is completely covered with clouds, we can still see what's happening under them.

Jim Green: Well, you know, communication with our surface assets on Mars is kind of complicated. You know, when we landed Curiosity, I don't see it carrying a big truck with a big dish behind it. So how do we communicate back and forth with, with our surface assets, like InSight, like Perseverance, like Curiosity?

Nacer Chahat: Yes, so we have two concepts to do so. The first one is to communicate with the orbiter. So we have orbiters around Mars which we can, they are dedicated for science, but for a critical event like that, we can use them to relay the data to Earth. And we also have on these landers and rover, high gain antennas that allow us to communicate directly with Earth but at lower data rate. So it's really a trade-off. When, when we should be using the orbiter or when we should be using the high gain antenna. Most of the time, we end up using the orbiter because it allows us to transmit the science much faster. So those are the reasons and most of the Mars mission have always worked this way. So we transmit the data to the orbiter and the orbit transmits back to the to the Deep Space Network on Earth.

Jim Green: Yeah, that sounds complicated, but it provides an infrastructure that allows any asset that's on the surface to be able to be relayed through our orbiting satellites. It's really an exciting time in in this particular field.

Jim Green: You know when the InSight lander arrived landed on Mars in November 2018 it carried with a two CubeSats and we call those CubeSats “MarCO.” What were they supposed to be doing and how important was communication for them?

Nacer Chahat: Yeah so MarCO was actually one of my first projects, and when I joined JPL the former director of the lab, Charles Elachi, challenged the lab to find a way to do real time communication during the lending of InSight. So with the existing orbiter we were able to collect all the information from InSight during the landing However because of the alignment of the orbiter, we couldn't get the data right away. 

Nacer Chahat: So the role of these two CubeSats was actually to receive data from the lander, InSight, and transmit these data in real time so the, the main challenge was to be able from these very, very tiny satellites which are the size of a shoebox, being able to transmit at the same data rate which was roughly around 8 kilobits per second. This was really difficult because we needed an antenna that was three times the size of the satellite itself. So we had to find a way to fold the antenna and deploy it. That's also the first interplanetary CubeSat so we had to ensure that we could actually survive the flight to Mars, which we did very successfully.

Nacer Chahat: When we witnessed the landing of InSight we were all excited because for those who actually follow the landing you should remember when they were saying oh we are now 100 meter 90 meter 20 meter and all the excitement was coming up all I had in mind was oh that's my antenna who's transmitting all these data and then he landed we exploded with joy and we finally received these first pictures from InSight on the surface of Mars which also got relayed using the MarCO antenna.

Nacer Chahat: If we did not have the CubeSats we would have had to wait more than two hours after that.

Jim Green: Wow.

Nacer Chahat: Because the orbiter was not on the line of sight.

Nacer Chahat So, that's such an amazing accomplishment that we've been able to do and that's really what's beautiful about working at NASA is that we're able to do things that nobody has done before.

Jim Green: Yeah i remember that time I was head of planetary science and it was really riveting and i was just delighted that the MarCO spacecraft worked.

Jim Green: And in fact, it was really nailbiting for the simple reason that we were having problems with one of the MarCO spacecraft very close to the encounter time. Do you remember that? And what happened?

Nacer Chahat: I do, I do, and we were very worried about that. So one of them actually restarted? Like, I think it was a few hours before maybe a day before, I don't recall exactly. So we were worried that one of the CubeSats would not be able to relate to data. But after it rebooted, it went in safe mode and rebooted in a nominal mode. And they both successfully related the data.

Jim Green: Well, you know, we're flying a helicopter on Mars for the first time. And we call that Ingenuity. Did you get involved in that? And what's your role?

Nacer Chahat: When I saw the first flight, I couldn’t help but think of all these hours spent working really hard to solve technical problems. All these people working on delivering hardware that you don’t necessarily see on TV. This achievement is absolutely historical and I am happy I got to contribute.

Nacer Chahat: My contribution was with the telecommunication subsystem, to ensure that the rover can send commands to the helicopter, and the helicopter can send images or telemetry back to the rover. So, I worked on the antenna design and also worked on the system engineering.

Jim Green: Wow, that sounds really difficult because this is a very small vehicle. What's that antenna look like? I don't remember seeing it. Does it stick out? Or is it part of… does it go up to the top or, where's it at?

Nacer Chahat: Yeah. So on the top of the helicopter, there is a solar panel, which allows us to recharge our battery. And we decided to locate the antenna on this surface, because this is what provided the largest area to use as a reflective surface. So this is the simplest type of antenna that you can ever use. This is called a monopole. So monopole is basically a single wire, which is resonant at the frequency of operation, and located on top of a reflective surface. And the reflective surface in this case is the solar array.

Nacer Chahat: This wire allows us to operate at the frequency of interest. But this antenna, this type of monopole antenna are being used when you need to communicate what we call omni, omni directionally. Meaning, we need to communicate this with the same capabilities in any direction, because we don't know where the helicopter or rover will be because it will constantly move when it's flying. Right. So that's the reason why we use such an antenna.

Nacer Chahat: It's very small it's about five to six centimeter which is basically a quarter wavelength or the frequency of operation.

Jim Green: Yeah, that makes a lot of sense. I mean, yeah, you move the copter and it comes back down. And it's not necessarily in that same orientation.

Nacer Chahat: Exactly.

Jim Green: So you want to broadcast. So it sounds…

Nacer Chahat: Yeah

Jim Green: …like though the Ingenuity communication is only with, with Perseverance, and then it's up to Perseverance to package that data and then send it up to an orbiter which then relays it back to Earth.

Nacer Chahat: That's, that's exactly it. And the reason is very simple is that obviously with such a small helicopter, we will not be able to communicate directly to the orbiter, and even less with Earth. So that's the concept that that we, we use. The helicopter is also has to, to, to stay away from the rover itself because the rover needs to be completely safe. So we have to keep-out zone which is roughly above 100 meters. So the helicopter to will never fly within 100 meters of the rover. So the telecommunication subsystem was designed to communicate from 100 meter to one kilometer, which is very far away. And we've done a lot of testing nearby our lab outside, a field test, which was very, very exciting, where we had a real size mock-up of the rover and the helicopter and we located it in different direction to make sure that all of our models and analyses were correct.

Jim Green: Wow, that sounds really fun. Another thing that NASA likes to do is think about missions that are in the future. And even though we're sending a spacecraft to Europa, called Clipper, we're also been thinking about what it might be like to get down on the surface, a lander. Now, you were also involved in the communication system for a lander on Europa. What would that be like? And how does that have to work?

Nacer Chahat: The original concept of the Europa lander concept was to send an orbiter as well, along with the lander, and the orbiter will have communication telecommunication capabilities to relay the data back to Earth. However, doing so would have been cost-prohibitive. So, we were asked very quickly to revise the concept to reduce the cost so that this mission could someday be possible.

Nacer Chahat: And the only way to do so was to communicate directly with earth so that we don't have to have an orbiter as well. So, to do that, the conclusion that was that we needed an antenna with an efficiency of more than 80%, which to give you an idea, has never done before. All of the Mars rover or lander, they have efficiencies of less than 45%, roughly. But the lander has additional constraints. The antenna needed to be flat, it needed to survive the environment, and very high radiation of Europa. And for those reason, people thought it was just not possible to do so.

Nacer Chahat: So we came up with an antenna design that fulfills all these requirements and achieved the efficiency we fully tested be something to the environment of Europa, to qualify the something out for a potential Europa lander mission in the future. And so now we're in a very, very, very good shape, because we know that this Europa mission concept is possible. We have all the technology that are needed to do that, because NASA supported us to develop all of these technologies.

Jim Green: Yeah, that's really great. Now coming back to the Earth, your current project is on SWOT, which is the Surface Water and Ocean Topography Mission. What are you up to with that? And have we launched it yet?

Nacer Chahat: No, we are right now we are in integration and testing, what we call INT. So the payload is fully assembled. Right now, we're actually currently doing all the environmental testing on the payload before we ship it to France to our partner in France, CNES, to integrate it with the spacecraft. So this mission is very exciting because we're pushing the boundaries of the science measurement accuracy. So the role of SWOT is to measure the surface topology of the ocean, but also the water surface for the first time. So we will have a global map of the entire Earth and we will be able to know where the water is continuously. And so that's, that's the beauty of SWOT. There is a lot of new technology that needed to be developed to do that, to improve the accuracy of these measurements. And so we're very, very excited to see this mission moving along and getting very ready to fly.

Jim Green: So what's the new advancement in antenna technologies?

Nacer Chahat: Every single mission have different requirements. So we tend to design a new antenna every single time. I would say that the holy grail of the antenna, from my point of view, would be to design an antenna that could be applied for every mission to meet any requirements. So obviously, that's, that's almost impossible to do so. But for communication, that's not impossible, you could come up with an antenna that could shave the beam in any way we want for a given aperture. And that's what I'm working on, on my research science, to achieve such a thing.

Jim Green: Sounds great.

Jim Green: Nacer, I always like to ask my guests to tell me what was that event that person, place or thing that got them so excited about being the engineer they are today. And I call that event a gravity assist. So Nacer, what was your gravity assist?

Nacer Chahat: The scientists that I respected the most is Marie Curie, who was also from the same country that I am from, from France. But really, what I like about my inquiry is her dedication for work. And I think nobody was as dedicated as her because she actually gave her life for her work. And the work ethic that she has demonstrated is what, what I share the most with Marie Curie.

Nacer Chahat: So but I would, I would say, as well, that it's not necessarily an engineer, or a scientist that really inspired me, in my case. My parents are from a very poor country, in Algeria, north of Africa. And they didn't have access to education. So, after they moved in France, I was born and raised in France, they really share this notion of understanding that the education is a gift. They didn't have the chance, and they wanted to make sure that that I realized the chance I had, and we could take advantage of the education I was given as much as possible. So that's why I always worked really, really hard to do as much as I could and learn as much as I could.

Nacer Chahat: And so I would say that my gravity assist are not engineers or scientists, but actually my parents.

Jim Green: Now, that's a wonderful story. Thank you so much for sharing it with me.

Jim Green: Nacer, thank you so much for joining me in discussing this fantastic topic.

Nacer Chahat: It was my pleasure. It's always it's, it's always great to share the experience that we have delivered developing new technology at JPL. So thank you for having me.

Jim Green: Join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green and this is your Gravity Assist.

Credits
Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Video producer: Sonnet Apple
Editor: Gary Daines

Source: https://www.nasa.gov/mediacast/gravity-assist-talking-to-ingenuity-and-other-space-robots-with-nacer-chahat

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Wspomnienia inżyniera bezpieczeństwa m.in.  ładunku w programie STS.

Gravity Assist: Breaking Barriers, with Dana Bolles (1)
Apr 30, 2021


Dana Bolles has had many jobs around NASA and is passionate about inspiring young people to go into STEM fields.
Credits: Dana Bolles

Dana Bolles has worked in many exciting areas of NASA including assuring the safety of experiments and spacecraft going to space, managing environmental programs, and thinking about the possibility of life beyond Earth. In her journey as a space professional, a key challenge has been encountering other people’s assumptions about what she can and cannot do. Dana gets around in a wheelchair and uses hooks for hands. In this episode, she talks about her experiences around NASA and how everyone can be a better ally for people with diverse abilities: “By getting to know us first, without preconceived notions, the benefit is seeing the community for the beauty we bring to living life every day.”

Jim Green: Behind the scenes of NASA, so many things have to work right for us to be able to make a mission successful.

Jim Green: Let's talk to somebody who has worked in many different areas of NASA.

Dana Bolles: With my disability, people tend to make assumptions about what I can and can’t do.

Dana Bolles: I would say that’s been the biggest challenge.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Dana Bolles. And she works for the science engagement and partnership division at NASA Headquarters. Dana was first hired as a payload safety engineer at the Kennedy Space Center in 1995. And since then, she has worked at four NASA centers and mission support roles, and at least 10 more years in the human exploration and science divisions. Welcome, Dana to Gravity Assist.

Dana Bolles: Thank you, Jim, for inviting me. I appreciate it.

Jim Green: My pleasure. Well, I really want to know what really got you excited and wanted to work for NASA.

Dana Bolles: So, you know, most kids would say, "Oh, I want to work for NASA". Right? That's a common, common thing. But more specifically, when I was younger, when I was thinking of all the different jobs to have, I thought, an astronaut, being an astronaut would be perfect, because it would, I would be in an environment where I wouldn’t need the wheelchair, and the fact that I don't have legs would be okay. And in fact, it can even be an advantage, right?

Dana Bolles: Because you're having to launch in these, these little spaces, these small spaces where you're all crammed in like, like sardines. And I thought, well I’d be, I'd be at an advantage, I wouldn't need leg space. And thirdly, I, I use artificial arms. So I, I was born without arms, and I use my artificial legs since I was two years old, so I'm pretty proficient in them. So I thought, that's a third reason why it might be an advantage to hire me as an astronaut, because I could use my hooks, you know, like the astronauts use the robotic arms. And so there you go, three, three reasons to hire me. (laughs)

Jim Green: Well, what was your biggest challenge, you know, that you faced when you prepared for your career at NASA?

Dana Bolles: One of the biggest challenges was, you know, I was getting my engineering degree in the early 90s. And still, at that time, there were, there was a handful of us girls and women in the class, but we were largely outnumbered. And so that, that was a weird feeling, right, being, being one of the few women and, going through the major. Also, the biggest thing for me is, with my disability, people tend to make assumptions about what I can and can't do. So I would say, the biggest challenge in, in my success in my career and working at NASA or wherever, is just having to always put up against those, those assumptions and limiting me so that, I would say that's the biggest challenge. And it gets kind of tiring, always having to, to prove myself, you know.

Jim Green: Yeah. But do you remember the time that you know you first came to NASA and how did you feel?

Dana Bolles: Oh, I remember that quite well, even though it was over 25 years ago. It was scary. I was going to the other side of the country. I grew up in California. And so here I was in Florida. But it was a really, it was exciting. It was scary. One thing that, that I remember quite well is the first months I was there, there were a lot of tours. And I'm sure you've been to Kennedy, and it's an amazing facility and…

Jim Green: It is.

Dana Bolles: And my favorite was to go to the Vehicle Assembly Building and you know, that building is what, 525 feet high? At the time, it was the second or third largest building and volume in the in the world. And I was just in awe when I got to see that and know that this was a place where the orbiter was mated with the external tank and the solid rocket boosters. And you know, looking at the crawler and learning all, all the process of what it takes to launch, was just it was exciting. It was overwhelming, and a bit scary. You know, that the responsibility of that. But yeah, amazing. It was incredible.

Jim Green: Yeah, that building we call fondly the VAB.

Dana Bolles: Right.

Jim Green: Indeed, I have never had the opportunity to be in it when they put together the Shuttle and the external tank and then the solid rocket boosters in the building and then put it on the crawler and then roll it out…

Dana Bolles: Right.

Jim Green: …to the pad. You know, but you see it on films and it's just it's just not the same. I tell you.

Dana Bolles:  Yeah, yeah.

Jim Green:Well, as a payload safety engineer, what was, specifically did you have to do? Is that for every Shuttle flight, or were there other things that you did along the way?

Dana Bolles: So let me let me first define payload. For people who don't know, the payload is basically, it's the purpose of the mission. So, it could be anything from an experiment, it could be a spacecraft, it could be the Mars rover, which, which recently landed, Perseverance. Those are all payloads. So at Kennedy, I was part of the ground safety review panel. So we looked at the payload from the time it arrived at Kennedy until the time it launched and cleared the tower. That was kind of our purview.

Dana Bolles: And we were assigned payloads and, and we would look at everything that was done to it for pre, pre-launch processing. So at Kennedy could be, it's everything from the time it comes through the gate, and you take it from the vehicle, and you put it on a stand, we had to make sure as the payload safety engineers, did the sling, you know, what is the rating of the sling? And when is it, when was it last tested?

Dana Bolles: And so it's basically looking at everything we're doing to it from the time they comes in the gate, is it safe for the people working on, it for the from the facilities and from the spacecraft itself, because it's thousands and thousands of dollars, that, of the American people's money. So those are the things we looked at.

Dana Bolles: Let's say the spacecraft has to be fueled, then we had to make sure that all the procedures in that process, you know, that they had all the safety built into it.

Dana Bolles: And then finally, with launch, that was really exciting, because we would have to be there at least a couple hours before launch, so that if there was an anomaly on the pad, we could help the managers know what to do next, for the process and the procedures.

Jim Green: Yeah. Now, this included not only shuttle payloads, but rocket payloads, too.

Dana: Right.

Jim Green: So, spacecraft that would be mounted on the top and then blasted into space.

Dana Bolles: Right. In fact, I had one of my payloads was an expendable launch vehicle payload, the EOV payload, it was the Mars Orbiter.

Jim Green: Oh, wow. Now, from there, you moved to NASA's Goddard Space Flight Center in Maryland to work as a fire protection safety engineer. What led you to make that switch?

Dana Bolles: You know, it was really hard to leave because I loved what I was doing at Kennedy and I loved the center. But coming from San Francisco, it was a really big difference for me to live in that environment, and I really wanted to be closer to a more metropolitan area.

Dana Bolles So with Goddard, it made more sense because it was closer to DC. And I had that access. And so that was my main driver, is, I just kind of I wanted a different, I want to live somewhere different. Goddard was, you know, I met some really good people. And it was in the life safety code, ensuring that we met the fire protection. It was a good experience. I learned a lot, but I was there only a very short year-and-a-half before I transferred to Ames Research Center on the West Coast.

Jim Green: Well, how did that opportunity come up for you to go from Goddard Space Flight Center in Maryland, all the way back then to California?

Dana Bolles: So as I mentioned earlier, I am a West Coast gal. And so what happened during that that time that I transferred… my mom, my mom was in remission from cancer for about 11-and-a-half years. And so while I was at Goddard her, that was when her cancer came back.

Jim Green: Oh wow.

Dana Bolles So that's when I decided I need to go back and actually the first year, I was back in California, I drove down from the Bay Area down to LA 10 times in the year so I could spend more time with her. And…yeah, so that was the main driver, plus just the fact that I really like living on the West Coast a lot. So it was, I was back. And then I was back in the Bay Area, which is where my heart was. So, um everything kind of came together perfectly.

Jim Green: Well, what's really great about NASA is it has 10 centers in many different states across the United States.

Dana Bolles: Yep.

Jim Green: So indeed, it gives you a flexibility to take your skills and ability and go and work at another center.

Dana Bolles: Right.

Jim Green: Well, what did you do when you're at Ames?

Dana Bolles: When I first transferred to Ames, I transferred into the Environmental Services Division, and I was a an environmental compliance specialist. So I managed the center's biggest environmental programs in air quality, hazardous materials storage and industrial wastewater discharge. And what I love about NASA is: We follow all of the environmental regulations. There's federal, state and local laws, and whatever is the most stringent is what we’ll follow. And so living in the Bay Area, that was a really challenging job. We had the most stringent environmental regs in the whole country. And so what that meant was I was mostly dealing with local regulators.

Jim Green: Well, is there one NASA mission or activity that you worked on that really stands out in terms of something that you're really glad you're worked on?

Dana Bolles: What I think when I, when I look at my entire career, I would have to say that payload safety engineer was the most exciting time because I was, that was the closest ties I had with the mission, was as a payload safety engineer. But I really appreciate… all of my jobs I've had through my 25-year career have been really awesome. And I've learned a lot from each one of them.

Dana Bolles And another another program that I was really impressed with being part of was the Human Research Program. And that was a really, in my opinion, that was a really top-notch program of NASA. And it was a, it was an honor to be part of their team, more at the program level, helping with all the elements, integrating them all, and also coordinating their program status review every two years. So, so that was a, that was an incredible experience.

Jim Green: Wow.

Dana Bolles: Mhm.

Jim Green: So you most recently came to NASA Headquarters to work in the Science Mission Directorate, and in particular, science communications. What got you interested in that topic?

Dana Bolles:  So what happened was when the call came out, through Headquarters for people who were interested in doing details, you know, I, it's funny, I, throughout my career, up until this time, when I did apply, which is this last time when I got it, I had no interest in doing a detail at Headquarters. But I just feel like the timing was just right.

Dana Bolles: And not only that, but the fact that you know, communicating NASA to the public. That's always been a great passion of mine. I mean, I do a lot of public speaking about NASA, and it's my favorite thing to encourage youth to go into the STEM fields, because we need our best and brightest. If we want to stay in this, you know, in the space game, right? We have to have the best and the brightest, so it's important to encourage them.

Jim Green: Well, in your work at NASA Headquarters in the science communication area, you've been doing a lot of thinking about the search for life beyond Earth. And that's a huge topic of interest in NASA. And in fact last season's Gravity Assist, we talked about the search for life. Well tell us about what you've been doing to support NASA in this area.

Dana Bolles: Well, my first year of my detail, I helped to create this toolkit. And basically, it was, it's an electronic resource for NASA employees, anybody who has a NASA email could access it. And it's to help people so that they can communicate about the search for life to the public. So it could be for people who want to speak about it, like, let's say an elementary school wants to hear about it. So somebody is interested, they can go here and learn about what NASA has done, and also part of that first year, I helped, I led a team of experts in the search for life, and kind of thinking about how can NASA be better prepared in mak[ing] an announcement in the future about finding life beyond Earth?

Dana Bolles: And so it's really it's been an incredible experience just sitting with this team that we have, listening to them just have very light, informal discussions about what can we do? What can we do to kind of help, and a lot of it is preparing the public on what we mean when we say certain things. And then there's another piece of it, you know, when the announcement does come up, what are some of the things we want to think about?

Jim Green: In fact, as you know, you and I've talked about that particular subject on a number of occasions,

Dana Bolles: Yeah

Jim Green: It’s one of my favorites.

Dana Bolles: Yeah.

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Gravity Assist: Breaking Barriers, with Dana Bolles (2)

Jim Green: And indeed, NASA is doing so many things across many of the different centers. And having a place where that can be accumulated and, and brought together is, is really important.

Jim Green: So in the area of search for life, as you're pulling together important information for all of us to use and leverage, what are some of the things that you think are perhaps misconceptions by the public in NASA's effort to find life beyond Earth?

Dana Bolles: I think the biggest challenge in making an announcement is that people are going to hear it and they're going to immediately go to the image of the great little green Martians on Mars, right? So a lot of it has to do with science fiction, and I think that feeds a lot into people's mis- misperceptions of what, what it looks like, what it could be.

Dana Bolles: I mean, more than likely, you know, based on what we know, now, it's it's going to be microbial, which we're not even going to be able to see. So, those are the things that are the biggest challenges. Just sensationalizing and that not to mention just, the media likes to sensationalize everything anyway to make a good story so that that kind of doesn't help when we're trying to be realistic about, you know, what it is that we're doing and how and what we're finding out there.

Jim Green: Now, I've heard that you've been named, and IF/THEN Ambassador by the American Association for the Advancement of Science.

Dana Bolles: Yes.

Jim Green: So first, congratulations.

Dana Bolles: Thank you.

Jim Green: And tell us what that program is all about.

Dana Bolles: So IF/THEN is an initiative of the Lyda Hill Philanthropies. And what she wanted to do was she wanted to encourage young girls like middle school-ish age to go into STEM. And so she thought, well, if we support a woman in STEM, then she could change the world. That's kind of their motto. So what, what they did, what this initiative does is it takes the talent agency model, and it promotes all of the ambassadors. There's like 125 of us. And it promotes us across the country in all these different venues and ways so that we could reach the most number of girls.

Dana Bolles: There's a virtual classroom experience where you talk to classrooms. It's called Nepris. So they're one of the collaborators with IF/THEN, and they get a lot of their speakers through the ambassadorship program. And there's show there's Saturday morning shows geared towards kids that encourage girls to go into STEM and there's all kinds of different ways that they're promoting us. And it's just been incredible. And in fact, one really awesome thing is there was a study done in 2016. Rosie Rios commissioned a study in 10 largest cities in the, in the United States. And what they did is they looked at all the statues that are in public, in the public view, and they found that of all of them, less than half a dozen were of real women, nonfictional women. And so based on that Lyda Hill thought, you know, I'm gonna change that. And so she took 3D scans of all of us. And they're going to display full, full size models of all of us all at once, all in one place. And it’ll be largest display of real women in science in, in the country, if not the world.

Jim Green: Wow, that sounds like a spectacular opportunity.

Dana Bolles: Yep.

Jim Green: In fact, middle school girls in particular, I guess, that's a critical time for which they then make decisions about whether they're really interested in science or not. So seeing the role models, seeing that they can actually step up and make a career of these kind of science and engineering and mathematics that, that they may be good at, is really important.

Dana Bolles: Yeah.

Jim Green: And I'm sure you're, you've really helped a number of kids along the way.

Dana Bolles: Yeah, it's important. It's important. They see, they see women like them, you know, because that way, it gives them more of a reality check that, hey, I could do it.

Jim Green: Well, what's the one thing that people could do to really be a better ally for the disability community?

Dana Bolles: Jim, thanks for asking that question. The one thing that people could do, to be a better ally to the community is to not see us for what we can't do. But be curious about what we can do. So while people's initial reaction to disability is often negative, and feeling sorry for us, they don't, they don't see that living this experience makes us better problem solvers. So by getting to know us first, without preconceived notions, the benefit is seeing the community for the beauty we bring to living life every day.

Jim Green: Well, NASA really looks for a diversity of people, because each and every one of our experiences, and that includes people with disabilities, brings a certain level of sensitivity, and a certain ability to solve some of the most complex problems that that, you know, we really face if we're going to learn to live and work on a planetary surface.

Jim Green: Dana, I always like to ask my guests to tell me what was the event, the person, place, or thing that got them so excited about being the engineer, they are today in NASA. And I call that event a gravity assist? So Dana, what was your gravity assist?

Dana Bolles: This is a really difficult question for me to answer. You know, at first, I thought it was, of course, it's my mom, she's the one who gave me my backbone. She, she helped build my confidence. And then, and then I thought, well, then it could be the principal and the teachers who mainstreamed me at such a young age. It could be my father who, not knowing him for the first 39 years of my life, when I do find him, I find that he builds spacecraft models for living.

Dana Bolles: So when I look at all of this, you know, I would say, if I had to narrow it down, I would say it would be people. You know, it's my family, my friends, my mentors. All of that kind of helped to give me the gravity assist, to come to NASA and to be successful.

Jim Green: Dana, thanks so much for joining me and discussing this fascinating topic of all the activities that you've been doing in NASA.

Dana Bolles: Thank you. It was a great honor.

Jim Green: Well, join me next time as we continue our journey to see what happens underneath the hood in NASA. I'm Jim Green, and this is your Gravity Assist.

Credits
Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Apr 30, 2021
Editor: Gary Daines

Source: https://www.nasa.gov/mediacast/gravity-assist-breaking-barriers-with-dana-bolles

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Gravity Assist: Always an Astronaut, with Ken Bowersox (1)
May 14, 2021


Ken Bowersox preparing for the launch of Expedition 6 on Space Shuttle Endeavour in 2003.Credits: NASA/JSC

“In some ways, spaceflight changes you forever,” says Ken Bowersox. Since he was 7 years old, Ken knew he wanted to become an astronaut. In his astronaut career, he participated in many exciting missions, including an extended stay on the International Space Station. What did he eat? How did he feel when he came home? Now a leader in NASA’s Human Exploration and Operations Mission Directorate, Ken currently works on plans for sending astronauts to the Moon through the Artemis program, with an eventual goal of Mars.

Source: https://www.nasa.gov/mediacast/gravity-assist-always-an-astronaut-with-ken-bowersox.

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Ken Bowersox brał udział w 5. lotach kosmicznych