City of Cupertino, CA NASA Speaker Series 2020, 19 Feb 2020

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From YouTube: NASA Speaker Series: Controlling the Uncontrollable

Description

NASA has landed in Cupertino for a year-long speaker series aimed at educating, motivating, and entertaining the community. The second event in the series was recorded February 19, 2020 at the Cupertino Community Hall.

The state of the art for entry spacecraft, such as the Apollo capsule, utilizes Reaction Control System (RCS) thrusters for steering. These thrusters are typically mounted on the backshells of the spacecraft to maneuver them during atmospheric entry. Deployable Entry Vehicles (DEVs), a new class of entry spacecraft, have no backshell. Thus, mounting RCS thrusters is a non-trivial challenge.

Dr. Wendy A. Okolo, an aerospace research engineer at NASA Ames Research Center, presents her efforts on the “Pterodactyl” project to develop the control techniques that will make maneuvering and precision landing of DEVs a reality.

A

Good afternoon everybody.

A

Since we have a little delay, apologies about that and thank you for your patience. I will keep my introduction short so that we can enjoy dr. coalos talk dr. Wendy, a eccolo is an aerospace engineering researcher in the intelligence systems, division at NASA, Ames, Research Center. Her focus is in the area of systems, health, monitoring and control systems designed with applications to air and space components, vehicles and systems.

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To that effect, she manages a multi-million dollar sub project on a system-wide safety project, leading a team to develop the monitoring, predictive and mitigation capabilities that will enable the safe operations of unmanned aerial vehicles.

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At 26 years, old Wendy became the first black woman to obtain a PhD in aerospace engineering from the University of Texas at Arlington. Her graduate studies were recognized and funded by the US Department of Defense through the National Defense science and engineering graduate fellowship Zonta international through the amelia earhart fellowship the american institute for aeronautics and astronautics, and the Texas Space Grant consortium. Other research awards include a resolution of commendation from the Tarrant County Court of Texas and an award for excellence in research by the women of color and stem at NASA.

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She has received a number of awards, including a NASA Ames Honor Award, an Ames innovation, Fair win a NASA space technology. Early career initiative award dr. Colo, is also the recipient of the 2019 NASA Ames early career researcher award, the 2019 UT Arlington distinguished recent graduate award, the 2019 women in aerospace award for initiative, inspiration and impact, and the 2019 black engineer of the Year award for most promising engineering and engineer in US government. Please help me welcome dr. Wendy Cola.

B

Okay, well, thank you all for coming and I'm really excited to be here. Thank you for the invitation. Deb, like Deb, said, I wear quite a few hats. Eddings.

C

And today, I'm going to be talking about one of those hats and please feel free to ask me: questions might be able to interactive a little too technical. There are no dumb questions, especially for the young people in the audience or the non-engineering non-technical people. I want to hear the questions. Okay, so today I'll be talking to you about one of the things, one of the really really cool things I get to work on, which is this project called pterodactyl pterodactyl?

C

How do you come up with a name like that right, I, work for the government, so we like our acronyms and we're looking for this, calling to make something fly and came up with pterodactyl and try to find like an acronym of what it would actually stand for like precision targeting entry.

C

Well, it didn't quite work out, I, don't know what we ended up doing, but it's pterodactyl now and it's a really really large project but- and you know just an overview- it's a it's a big project. It's a large team of people located at NASA, Ames, Research Center, a Johnson Space Center. Who knows what Johnson Space Center is you're not allowed Danny you work at NASA. How are you even here? This girl works at NASA with me, who.

B

Knows where Johnson Space Center is yes in Houston.

C

Houston would have a problem so we're at AIDS or a JSC. We have partners at the Applied Physics lab Johns Hopkins Applied Physics lab. We have partners at UC Davis, so it's an early career. You know project that we put a proposal together about five of us put this proposal a couple years ago and NASA headquarters. The space technology Mission Directorate gave us 2.5 million dollars to go crazy and we did so. The names that are bolded here are the control team that consists of myself.

C

Benjamin Margolis holds a controls, engineer, pathway, student now, I'm NASA, employee and Jeffrey Barton, who is at APL. So we leave that we are the controls, team and I lead the controls to move these people so they're. You know all these different facets to the project and I'm the controls lead on that, and so what is pterodactyl and what is this work that I'm going to be talking to you about today?

C

So the motivation behind this work is really that precision targeting right. So if you have an entry vehicle or spacecraft sets aligned in a certain area, the closer you are to your target. The more improved your precision targeting is the easier the more cost affordable. It is operational recovery costs and timely sample renewals. So you don't have like this large envelope right there you're going to get your spacecraft back from you can kind of do better with precision targeting and that's really the big picture. How can we improve precision targeting this is driving?

C

You know a new class of vehicles that will enable small and large mass missions to other planets lunar sample return for a salute of Mars and support of the different programs that you know, NASA is embarking on. One of the big ones is: what's the big thing we keep hearing NASA talk about these days, Mars. What's the program called Oh? What's what is it? It's not around is a big one. Big, you know bullets. What is it? What is the way I'm gonna support?

C

What's the big thing, I'm gonna get I'm gonna, give you a hint a poll of.

B

C

Our poll had a sister like Greek mythology gets NASA here, Artemis the Artemis program, so Paul had a sister. You know we went back to the moon, went to the moon. What the 50th anniversary of it was last year when Sam Lewin and you know, did a little stuff and everything and we want to go back- want to go back to the moon and land, the first female, the first woman on the moon, so we're calling it Artemis.

C

You know we're trying to go back and actually do some release cool stuff there, and so you know if you're on the moon and you want to send a sample back or you want to do something cool and you don't really need a large spacecraft or something on the order of the Apollo capsules. You know there's this new class of vehicles that can achieve this and they're called deployable entry vehicles.

C

So these small and lured missions are kind of driving these and a deployable entry vehicle doesn't really have that rigid body when you consider the Apollo capsule is something that is stowed and then during entry. It deploys.

C

So when you have something that's small that can then deploy, it means you can, you know, reduce the volume constraints you have so the one we're actually working with works like an umbrella, it's still like an umbrella and then it deploys during entry, and so the challenge with these kind of vehicle is this because they don't have that rigid form right. Imagine like a bowl with the lid like Thapa, where it has a rigid form, so you can put things on the back of it where you can stick things there.

C

Well, these don't have a rigid form and traditionally entry vehicles were controlled by putting thrusters on the backs of these vehicles right, that's how we've controlled and your vehicle. So as long as remember, you can put reaction control systems that can fire in pairs on the back shell, as we see on the left hand of that plot, so RCS is called, is a a short form of reaction control system.

C

So you can put RCS on the back of these vehicles and control these vehicles for heritage entry, spacecraft, but when you don't have a back shelf or a deployable entry vehicle, what can you do, and that is what this project is really trying to solve? Looking at control systems, how you can control it, approval entry be equal. What kind of control systems can feasibly be integrated on something that doesn't have a rigid shell that stills and then who deploys during entry? So DVS have no back shell.

C

You have your payload and other subsystems in the back and that's the four body. So how do you control this thing? And so again the research question that we're trying to answer in the you know, past couple of years is what control system can be integrated into the DV and enables steering to a target location. Precisely remember what I said: we want to improve precision landing and so here's the baseline mission that we're looking at on the left side. You see the descent activation system on the right side. You see where active guidance starts.

C

So when you think about entry, there are multiple phases: there's the entry phase, there's descent phase and then there's the landing phase, we're concerned with the entry phase of the vehicle moving through the atmosphere, so we're looking at a lunar return mission, kind of like a stress case for loads, which is why we chose that mission focus primarily on the entry face and that's the entry interface that we're looking at altitude and velocity. We are not concerned with decent activation or whatever parachute or landing system, actually gets it into the ground.

C

We're just saying: if you look at that footprint that space, where you're supposed to be targeting. How well are you doing with that? And so this is the baseline vehicle, the pterodactyl baseline vehicle that we're working with I can call it at PBV and it's an asymmetric vehicle. It's asymmetric. Who can tell me looking at this vehicle why it's asymmetric just looking at the picture on the left-hand side.

C

Yeah I'll set the CG, but why does it? Why would we consider this vehicle asymmetric? Can I point can I point with this? Is there a laser pointer come on Oh, wonderful, so this vehicle right here? Why would we consider what is symmetry in first place? What is symmetry when something symmetric? What does that mean?

C

Yes, so one half is similar to the other half right. So it's symmetric. We hopefully are mostly symmetric right right, I hope. So one half is similar to the other half, but that half doesn't have to be left-right. It can be up-down. So why is this vehicle not symmetric.

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C

This side is shy, who said it yeah the leading edge is shorter than the trailing edge. So there's more on the bottom here. Maybe I should kind of look at this side too, there's more on the bottom here than on the top. So if it was a perfect circle, it wouldn't be a symmetric, and this is important. I want. You know, I'm pointing the self a reason this vehicle is asymmetric, the vehicle our baseline vehicle, this vehicle exists. We took that and said, okay.

C

How can we make this deployable entry vehicle fly and do some tweaks and watts to it, but it is not a symmetric vehicle. So that's gonna be interesting right. It's not a perfect circle, there's more on the bottom than on the top. So it's not symmetric. So this is the baseline vehicle that we're working with and it's important. The ports of this asymmetric will come in subsequent slides. The diameter is 1 plus meter, mass LBD and off air. Don't worry about those so leading the controls team.

C

What do I care about right, remember, I, said this team is a large group of people at JSC, Ames, APL, UC, Davis, Mentors, different teams. As a controls engineer, my background is controls what I gotta pee jee-in, what do I care about? What is controls or when you think about aerospace? There are a number of different disciplines. There are people that care about structures, that's like the body of it. The material right you sitting on that chair now. Can that chair withstand the weight that you're putting on it?

C

That's what a structures person probably cares about. There are people that care about propulsions. What is propulsions the engines right and how much thrust you can generate what kind of thrust you can generate through that are aerodynamicists right, aerodynamicist in very foams, it's not even just aerospace, Ryan, Mechanical, Engineers aerodynamicists, that are they care about cars and the way the cars are shaped, the streamlined shape of the cars that can help reduce, drag so I'm controls. There's a field of guidance, navigation and controls.

C

Guidance is where do you want to go navigation is where are you now controls us? How do you get there right, so it should probably be NGC, not GNC, but everyone calls it GNC. So, as a controls engineer I care about one taking the aerodynamic data that basically describes this vehicle taking the mass and inertia properties of this vehicle and then understanding it right. First, you want to have an intuitive understanding of this vehicle. What it can do, what are its limits, create a representation of vehicle and I'm going to show some slides about that?

C

That's just the math right. Looking at that vehicle in the previous slide. What does what does this mean? What can the math about this vehicle tell me about you know what I can do with it then utilize this information to command the vehicle to follow guidance. Trajectories guidance is where do you want to go right? So guidance tells me this is where I want to go, and then I use my controls, information to move the vehicle there and it can be position. X, Y Z can be philosophy. It really can be anything.

C

Any states like I want to command the states to move from where they are now to a desired state. That's what controls is so now you just got a crash course on controls, aerospace, engineering controls.

C

How many people here are going to be controls engineers, ha so yes, and then compare the different control systems that were going to look at and then down so like this is more for the group as a whole, and so here are the control systems that we look at the first one was reaction, control systems, as I had shown for the heritage air entry vehicles. What they typically have is like the thrusters and the back shells that fire and they can kind of fire in pairs to maybe rotate the vehicle one way or the other.

C

The second is flap control systems. Who knows who that is not an aerospace engineer and knows what a flap is in terms of arrow. Okay, it's what it's like a wing. It's like a wing, have you ever been on a plane and looked out the windows, and you see the wings right. You can see the wings, but then you see these flaps on the kind of like the back side going up and down, and you wonder what it? What is that right?

C

There are people that wouldn't I had a friend ask me like: why don't they control those things I'm, like those things, are used to control the plane? It's it's. It's mind-blowing right, so they're aerodynamic control surfaces and when they move one way or another, the plane does something. So sometimes you see the ones go up on the right side, the others on the left side and your plane will roll like conduct some sort of maneuver. So those are actually control surfaces.

C

So, instead of your engines, firing you can put flaps and then deflect them one way or another to make your vehicle roll pitch or yaw and then moving mass control systems. Basically, this is just moving a CG around someone had said something about a CG offset right. So imagine imagine this. You know this is just imagine if I had, if I didn't have this like solid footing on the ground and I have my hands out like this and then all of a sudden, you place the weight here.

C

What would I likely do if you put something really really heavy on this end? What would happen exactly it would roll it would like rotate this way with this axis of rotation. So if you move mass from one side of a body to another, you're gonna cost it to rotate. So you could maybe try to look at that for controlling the beagle rotating and, following you know, it's commands so reaction control systems, RCS flap control systems, FCS and moving mass control systems. Mncs I, might use these interchangeably. I will not quiz you.

C

So if you don't remember, that's fine, so these are the control systems that we look at. What's the flood design like. So if you remember the body, the pterodactyl baseline vehicle body earlier, we put flaps on them, as you see here, two on the top two on the bottom, two on the right and left eight flaps to increase control authority and reduce multi axis coupling, because this vehicle is not symmetric when you roll it or you do something or you yo it.

C

You get some coupling in ways that you wouldn't really expect, but it's not symmetric. If there was a symmetric vehicle, you wouldn't have as much of that and so to reduce any. We already have a question.

C

So there is a symmetric version of the vehicle, but this is going to get a little interesting because it's a symmetric like that the lifted drag is higher right. So the L of a D anyone yeah the lips to drag ratio is higher and when you have a high L of a D, that vehicle was actually designed to follow Bank angle command. So when you have a higher elevator, you can do more in terms of guidance, so they added that more the longer more and the ribs on the bottom.

C

So we took that vehicle took the most complicated thing and decided. How do we control this vehicle right? We could have gone simpler, but I don't know they gave us 2.5 million dollars, you're like let's go crazy, but yet so it was to improve the L of a Dean. You can do more in terms of Bank angle control. Yes,.

C

Yes, so they they happens to be, but it's not because of that it was packaging and storing requirements that made like the ones on the bottom, a little shorter than the ones on the top. But that's a very, very great question. The asymmetry will manifest in different ways as you go through the design process, but from a flap design standpoint. The asymmetry are from a control standpoint: I didn't really care about. The asymmetry is how much control Authority could I generate?

C

The flaps have to be size, big enough that when I would deflect them, they were able to do enough of what I wanted the vehicle to do to fight any coupling or deal with anything like that. That's really what I cared about.

C

Possibly, if you're trying to generate equal and opposite commands, but you might not right, there's some yeah, you may not. You may not like, depending on so there's some l of a d. What if you want to perpetually remain like in this orientation and then you might not need to pitch up as much as you need to pitch down, so it kind of depends on what the goals are, and that kind of tells you why there's this interplay between guidance, where you're trying to go controls? How you get there navigation, where you are yeah?

C

These are great questions. So this is what the flap design is just some more information about the vehicle with flaps integrated and then the flaps can go from negative four to five behind to twenty degrees into the flow. These are just arrow and packaging and aerothermal constraints right we're talking entry. So if you go too far into the flow, then you have we start to have heating. You know you starts, have heating restrictions and shock waves and things induce on the flow.

C

So this was about placed by us for the vehicle based on packaging and era, thermal constraints.

C

The moving masses similar to the flaps we put eight on there, actuate similar to flaps and then the mass size limited by the stowed state first cut starting the same with the RCS. It was just that we didn't have. We had APL, do the sizing study for the reaction control systems and they recommended locating thrusters at a certain reaction radius and recommended the kinds of impulse requirements as well that we would need so we have four repressed areas, not new that can generate one Newton nominal thrust.

C

Don't worry about that, but basically this is just an overview of the flight control system. It's the reaction, control systems and the moving mass control systems, so I talked about Bank angle commands for guidance, so heritage systems would typically do Bank angle, where basically they're changing one of the angles the bank is, you know one of the important aerodynamic. You know, parameters they're, changing the angle, so kind of modulate lift.

C

So you have you a velocity vector and then, if you change that, if you change that angle here, you can change the direction which your vehicle is facing or where's going. But then you can also do another thing where you change. Instead of just the one angle, that's coupled and moving your lift vector and all that you can change your angle of attack, which is basically how you're pitched up and you can change your side slip.

C

So if you want to go up and kind of increase your down range, it can change the angle of attack. If you want to steer left, you can change your side slip. So just remember. This angle of attack is for up down kind of and side slip, it's kind of like left-right. So this is an alternative to what heritage vehicles typically do for guidance, so you could do Bank or you can do alpha beta, which is angle of attack and sysop, so I'll typically say Bank or alpha beta and of the vehicle yeah.

C

Yes, so we started out with this baseline vehicle that already existed, we're calling it the pterodactyl baseline vehicles, because because we have to make some modifications to it, that baseline vehicle is based off a lifting nanoa depth vehicle. So NASA had about four deployable entry vehicles like for unconventional vehicles under consideration for, like you know these Mars missions, it was an inflatable one hi-hats. So you know how this kind of deploys with like an umbrella with like the the rigid struts and stuff than that was high ed.

C

That would deploy like like a floater kind of like pneumatically, so there's high others, the Adept vehicle there was the MRV and then there's one more that that I'm forgetting what was it drawing a blank here. So we took that base vehicle and then went through like the package in like the CAD models and basically came up with something, but that resulted where we can at the flaps RCS fmcs. But we start out with the baseline vehicle because we were concerned.

C

What we're trying to do was not design a deployable Avenger of the entry vehicle but design a system that could control and integrate a control system on an entry vehicle. So our we had a starting starting vehicle to work with, which is an interesting question, because then we're basically saying give me a deployable entry vehicle or give me any entry vehicle at all and I can roll it in ways that are unconventional yeah.

C

Okay, so flaps moving masses and RCS the capabilities to do alpha, beta control or a couple downrange control for the flaps, its our flap deflection angle into or out of the flow for each of those eight flaps for our moving masses. It's. How far are you moving each mass along the ribs, so you imagine this umbrella and then you have masses on its rib and then you moving them in and out. How far do you move to control and then the for the reaction for us there's you're just firing on or are you firing off?

C

That's it. So these are the control outputs for one. You have deflection angles for the other. How far you moving the masses for the third one? Are you firing on? Are you firing off and so I take yes,.

C

I will get to that okay, so that really is the next. That's that's the crux of this right, so you have all of this information that how do you simulate it? So entry systems are pretty pretty simple in that they don't require a significant amount of computation on board. It's typically done on board, but you have all these all these pieces from the different place. You have aerothermal, you have the aerodynamics. You have the controls guidance, all of that working together.

C

A lot of this is done offline, which is what I'm going to show you and then it's a you know it's pretty simple, relatively easy computation that can be done on board. Okay,.

A

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So we have all that information, and then we want to develop a simulation model design control now that we have all these different pieces right. Where is the math who's excited about the math? Yes, yes, okay! So this is arrow. 101 that I got from a NASA website was putting these slides again. That was like okay, well, I, don't really.

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Target audience- and let me just you know, give you some you're gonna you're gonna enjoy this so, but this is publicly available like information, you can teach kids literally like forces and moments on a plane, and you can teach yourself to any of those I didn't like math growing up the stuff is easy, so imagine an airplane that has the vertical force going up. That force is called lift and a downward force called weight. When you lift equals weight, you are in something you can consider like an equilibrium.

C

You're a trim means you know, you're, not accelerating up or down you just you're here right, because you're, equal and opposite thrust and drag works the same way but in different axes. Thrust move you forward, drag slows you down drag is not always a bad thing. When you're landing you want drag right, you don't want to move, accelerate, you know off the runway, so drag. You know it's not a bad thing. So these are the four primary forces on an airplane they're side, but we can ignore those.

C

For now we might talked about those flaps so next time, you're in a you can see through the window and look on the wings you're gonna be mesmerized. By the way these things will flow up and down on the on the edges of the wings.

C

So when your lift is greater than weight, what happens with the plane? It goes up when it's less goes down and drag is greater than thrust the plate slows. One thrust is greater than drag here. Plane accelerates, F equals MA right forces mass times, acceleration, okay you're with me, then there's more I showed forces all right in different directions: there's more there's roll pitch and yaw.

C

These are called moments or what's another word for moments that the mechanical folks, typically like so I'm an arrow girl, I call the moments, but mechanical people called them torques right, so people are more familiar with torques they've heard of a tort. A torque is a force moving through a distance right so again put weight here. That's a force boom.

C

That's the distance right so force moving through a distance. That's a torque or that's a moment depending on what direction that moment is happening. Right is what determines if it's a roll, if it's a pitch or if it's a yah but they're, all torques they're all moments, a roll is a rotation about kind of like the nose coming out so this. Actually, this is a really great way to explain it this. If your plane is like this, this is a roll.

C

When it's doing this, can everyone see that this is a pitch and then this is a yawl right exactly so, and then your force is basically just this or that or you know, but depending on what axis you're rolling around roll pitch and yaw. So I put this here to kind of show. Let me before I get to the equations that I'm going to show some equations, but they're just I want you to get hung up on equations, there's just a few key things that I want you to. You know so. Take from those equations.

C

Don't ask me about these equation. It's gonna take three hours to get to all of this, but I just want to show you, so you have this vehicle that can be represented with a set of equations of motion. These equations of motion are typically nonlinear right, but they are dependent on the forces. I just showed you, your drag, lift and side forces and then the moments I just showed you right. That's what's key. These things go into the equation. So when you talk about representing a vehicle, you have to understand how that vehicle depends.

C

What are all these things that go into the representation of that vehicle? So it falls out of the math, so you need those aerodynamic forces and moments write. These equations are pretty standard right for an entry vehicle. What changes is, what are those air forces and moments that are going and what is the inertia? What is the mass distribution? Inertia is. How is mass distributed? You know across the body right through a body. So what are those parameters that change? That's what really changes?

C

Cuz, all these things go in here and a vehicle would change from another vehicle depending on what what you know you fill these equations with, and so these forces that I talked about side for slip for a strike, force, roll pitch and yaw moment they have coefficient. So an aerodynamicist will give me these coefficients and for an aircraft right, because we don't go that fast through the atmosphere. I mean you might think we go pretty fast. Well, we don't. It still takes us six hours to get to DC six hours Deb six hours.

C

Why am I in a plane for six hours when the technology exists? That will get me there in an hour and a half it's just a little loud, but people don't like that. It's loud they complain. This is a true story.

C

They actually complain, that's why we don't do it and then they complain and Congress passed a law that says you cannot fly supersonic over the continental United States, but it exists so next time, you're stuck in a plane for six hours, just know you're stuck there, because people complained that it is too loud and their dogs and cats are going crazy. True story, it's in the papers, but so so air, please don't go really fast, so you're aerodynamic coefficients, don't depend.

C

They really just depend on like angle of attack and pitch, and you know the deflections and things like that. But when you get into space right spacecraft, entry there's a lot that changing your Mach number. Who knows what Mach is I.

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Who knows what Mach is? Okay speed, it's very very heavily dependent on speed, but it is in relation to the speed of sound. So when you're a Mach one, you find out the spit of style when you're greater than Mach line, you're supersonic when you're way greater your hypersonic, then you get to transonic when you're below Mach one subsonic low subsonic regions so depending on how fast you're going right these things kind of affect the aerodynamics of the vehicle.

C

So when you get into the entry in spacecraft, it gets a little more tricky dynamic pressure, Q bar half Rho v square, depending on velocity as well, then your alpha beta or your angle of attack and size, so I'm going to say alpha beta a lot just know alpha is angle of attack. Beta is slight slip and then your aerodynamic data also depends on these aerodynamic control surfaces. Remember so, if you deflected all the way into the flow, the aerodynamics of the vehicle experiences is a little different than if you're not deflected at all.

C

So all of these go into those equations. That's all you care about with those equations. So you need your air forces at moments to characterize the vehicle and design the controller, and your aerodynamic forces and moments are dependent on these coefficients where these coefficients have dependencies on the baseline vehicle and they also have dependencies on the flaps when you're looking at the flat configuration. So if you're not looking at the flat configuration these terms right here on the right side, just go to zero.

C

So for the Flex, because their error surfaces, they also contribute as well. So you take those no linear equations.

C

You want to take them from non linear to linear, so you linearize through a process that one we will not go through today and you're. Trying to get this gain matrix, K, remember, I, said: Controls is taking you from where you are to where you want to go, and so X. Consider X is where you are your States now, where you are X desired, is where you want to go and there's this magical cage gang matrix.

C

Then, when you figure it out, it'll take you from X to X desired, and so you basically plug that you back in here, you get this planned dynamics. This closed loop and you solve for K such that one, your system is stabilized to your system, goes from X to X desired, while balancing objectives, what are the objectives? How fast you want to get to X desired you're here you want to get there. How quickly do you want to get there? You want to do a leap. Do you want to walk slowly?

C

These are the things that you as the control engineer. You want to kind of figure out how fast I want to get there and then how much energy am I going to use like how much control effort door. Am I going to use what's worth it to me? Is it worth it for me to jump and be out of breath and then come back here?

C

Maybe maybe not if I'm gonna jump and then just go home, but if I have to come back here and speak I'm, probably just gonna walk so you're balancing all these objectives, that's what controls it! This is so cool right. So it's like how fast you want to get there. How quickly do you want your states to get there? How much control effort do you want to use?

C

These are all the things that kind of go into that and show you work through all of that, so they can get your control design and we did this linearization split based on something that I did in my thesis for my PhD such that each time we get an update from the aerodynamics team. Remember I said this project. Is you know multiple people working together, so aerodynamicists gives me info and I'm like okay.

C

This is what we can do with this vehicle and then I pass that on to the guidance, and then they run the trajectory knowing the limits of control and it's good enough and then we work back. You know it's a very, very iterative process, and so each time the aerodynamicist gives me info I can work through that entire process. So I can split it such that it's not everything, that's changing it every time. So this is really really cool and I'm going to show some references.

C

If you have questions like this is all like been published and since what my PhD days of years ago, a few years ago, so it's public information and you're not basically really nervous I'm.

C

So if you think about that entry phase, that I showed you from entry during entry, the vehicle goes through different Mach numbers and different dynamic pressures, m and q mark number and dynamic sure, and you can like I, said linearized your equations of motion and then evaluate at different points. So your vehicle take this. Your vehicle is represented by a set of nonlinear equations, but you want to design a linear controller for them, because linear is good like non linear. Linear is good. Linear is easy right.

C

So if you linearize so you kind of linearize in a region and say this is valid in this region and then you can test it in another region and see how well you do right and most times for entry vehicles, because things are as crazy, you're, usually fine. If you linearize hair, you can usually fly here with the scene. You know with the same assumptions you made and think it's kind of work out, so you can pick a point and linearize we did.

C

Two Oh ended up just using one, because one worked fine and then can utilize that controls design for the three RCS FCS and M MCS control systems. Who remembers what mmm CS is mass moving mass control systems? Yes, you're with me? Okay, so you can utilize the control design for all three configurations. But first we want to understand. In what regions can we control this vehicle? What are the limits of controlling this vehicle?

C

This is gonna get into that asymmetric, various symmetry conversation and we're limited and what happens when you try to control and what are the things that happen? So what are the limits of control things week before you even start the process so ignoring this curves, because it's gonna take awhile to explain what I just want to notice that when you induce a yaw moment on this vehicle, when you cost this vehicle to do this, it also happens to want to do this.

C

But this is what you care about right. So if the vehicle is fine, this way during entry, you want to yell it. Maybe that way, because that's your target- and so you yard that way. But then it also wants to rule. So you have to figure out how to stop that roll, and it's called trim II have to figure out how to trim out that way to figure out how to control that roll away right because y'all and then it wants to roll some way.

C

These are just graphs depicting that, so you have at some none zero site. So if you have y'all like okay, we're good with the our trim and then you go and look at the roll and you say: oh, you have some non zero roll and you have to be able to control that as well, but we design this controllers to ideally be able to do alpha and beta we're thinking about roll. So what does that mean? What does that mean for us?

C

Y'all induces a roll moment that the vehicle needs to trim out, and this is just some additional plot saying as a result of that roll moment, that the vehicle needs to trim out your site. Slip range is limited, so you don't want to yaw too much and then induce a roll that you can't control, because you didn't design to be able to control that roll.

C

So you know kind of you know limit yourself in terms of site slip, so you don't induce as much and then when you limit yourself in terms of site slip, how good is your performance? How good is that guidance? Trajectory? That's really depending I mean your guidance is thinking you have more to work with, but you don't so that what does that mean for you?

C

So basically what the vehicle and the configuration we looked at the site's the commands require constant roll reaction moments to trim, and if you do that's for alpha beta, remember, I said that was Bank angle come in and there's alpha beta Bank angle requires roll moments only when the roll is changing. So what we should with this trim ability characterization. How well we can trim is that okay, the control envelope for what the vehicle can trim will guide. Where guidance goes. What does your guidance trajectory? Look like?

C

How far can you go right because we're telling them not? Okay, we can't go as far the big finding is the alpha and beta. Have these coupled ranges due to that role? You're coupling and our window here is where we can operate successfully and this window might not be sufficient for an optimum guidance trajectory. So alpha beta is not possible for this vehicle and control configuration. So we can either look at Bank utilize. The induced role for a bank remember I, said we have Bank and we have alpha beta.

C

That vehicle was designed for with that asymmetry or we can redesign the control hardware and I'll say: okay, we have the ability to trim out any role, that's induced so for this results. What I'm going to show you is? We looked at the ladder we're working on doing the former. Now, maybe that'll be another presentation: I, don't know if I have the bandwidth but we're working on doing the ladder modify the control system to say.

C

Okay, now we're only going to do Bank the same thing: we're looking at the flap deflections the moving masses, the Jets on and off and saying how well can we follow bank angle commands of rolling? So this role is a problem, but how can we use it to our advantage for a bank angle guidance, trajectory tracking? So we did this yachts, a bank architecture and the control design. Where we take our gains that drive the bank angle, convert them to basically a slice leap, so we know that we have this coupled side slip role, interaction.

C

Now we take that slice of command there's papers on this and I'll show the references, so you can take all the pictures you want. You can just go, get an arrow blade paper. So so you take that Bank on bit, convert it to you, basically take the size of command and that slice that drives your bank angle, utilizing that coupling- and this is a control architecture. If you're in controls, you always see feed like a like a block diagram like this controls, people's our major major major block diagram people, question.

D

C

Yes, yes, you can, you can get it and a lot of that characterization can be done way before hand right. There are things called stability, derivatives, static stability, derivatives, dynamic stability, derivatives that should either be positive or negative. If it's negative, how negative is it if it's positive? How positive is it and if you're not stable, the linear, quadratic regulator, design that I showed does two things it'll control and it will stabilize.

C

Ideally, you should be able to control supplies, but you can check those things because if you're not stable and you get into a mode like that, you can start to roll to infinity and just that's it. So what happens like it's a thing, but you can pull you can check it before you can check it before you fly. You can check or move before flight yeah. Well, you can. You can check these things before beforehand.

C

So that's what goes into that understanding the vehicle that intuitive understanding of the vehicle, because it's garbage in garbage out, if you don't understand the vehicle, if you don't understand what you're doing and you start with uninformed physics, you know you can go through and you can. Oh, these equations exist. You can always go through this process, but if you don't understand it's garbage in garbage out and then you have a problem that you having to explain to you know so the word for the world.

C

So so we did that he is that control design and then you know develop this control comparison metric to compare across all three designs. How well are these control designs in comparison to one another, and we looked at the bank angle, acceleration Yes No.

C

The angle only actually so the length that they're deployed is fixed and then it's the angle into the flow. So we don't control how far that was one of the options that will fix the rule problem. So that's what we're doing that's what we're doing next. Actually so, if you pivot, so so, the flaps you'd. Imagine the flaps like this right, they're just going into the flow, so the generative force they're not able to really generate a force that is in this direction right and then so you can't roll or force them I'm.

C

Getting my 3d mixed up now, but if you were to pivot, then you're gonna be able to generate more control authority in an additional axis. So instead of it been like really pivoting what about a twist like when you think about like these propellers, you know. So that's that's. What we're looking into next, like that was the next step for this and we're working out. I mean I, had meetings today that we're talking twist angles and Kant angles and all the options. You know we had good time. We had money, so we went crazy yeah.

C

But that's a great question: it's a great question, um so we'll look at Bank angle acceleration for how well we're doing so. This is a plot of during entry. Your Mach number versus your dynamic pressure. So imagine the vehicle going through this. This is just like a sample guidance trajectory. Imagine a vehicle going through all of this and we start our GNC activation somewhere on the top left like at that point there the CCNC activation. Then we go to.

C

We have this maximum dynamic pressure location and then we don't go all the way to the bottom. I said entry we're only care about the entry phase, and so we evaluate that metric that we've defined there at two different points of the flight envelope. Basically, how quickly can you accelerate using each of these systems? The bank angle acceleration?

C

How fast can you go using those three control systems and see how well you're doing, and so we saw that the RCS has a bank angle, acceleration capability of about 11 degrees per second square, we're at the minimum that you have have is 5 degrees per second square for a good trajectory. So RCS is good, but RC has better be good. It's heritage, it's what everyone's been doing right, so it will be good.

C

Then, at max Q we see that the flap control system is 11 like 1 1, 5, it's a 115 and the MMC s at max Q is 13.8. Remember our bar is 5 right. So we have these swaps able to get us like so much more at max Q for the FCS mm. Cmcs is good. Rcs is also good, but then add GNC activation max Q is important because max Q is basically an artifact of your. Your aerodynamic control surfaces depend on dynamic pressure.

C

If there isn't enough pressure, if there is no dynamic pressure, your air control surfaces really can't do anything so max Q is really important, but what happens in GNC activation in terms of these thresholds? Gnc activation, your FCS is still fine. Its 11.5 Lauria mm CS is now 1.48. You are not able to achieve the bank angle acceleration for these vehicle, for this configuration to meet even the limit of 5 so automatically this has got to go you throw this out. Yes exactly.

C

You know we're comparing these three this. If this isn't little work at GNC activation, it's not great enough, so these are just for us to show how well our RCS tracks. This is your bank angle two plots once the truth. One is the command, and then we do the same for the FCS beta, alpha side slip, truth vs. come in and they both track well, mmmm CS.

C

We don't even show because we're not able to reach that threshold or Bank angle acceleration and the down selection we chose is to go with the flat control systems for these vehicle. It has exceptional control system capability, a notable available, payload volume, and we can basically improvement of your ability and comparison to the RCS heritage, vehicle's heritage designs.

C

So in summary, we designed this control architecture that can hand either alpha-beta or Bank angle commands it's a multi-input multi-output linear, quadratic regulator, controller that allows for over actuated vehicle control, so multi input means there are many like the one could be eight flops and the multi output. It's like you're controlling three things: alpha beta bank, for example.

C

This control design is adaptable to other vehicles and actuator configurations. The royal coupling renders alpha beta and feasible for this vehicle. This controlled this mission and mechanical limits, and then the yalta bank, you know, was an attractive solution for this. So the control capability estimate for your bank was the achievable Bank acceleration with that sight, slip dependency and the Yoda Bank basically leverages the royal coupling that is inherent with the vehicle to achieve increased maneuverability compared to the heritage.

C

Rcs FCS has the highest Beckman over bolita, like I, showed it's like 115 max Q, compared to the minimum that we need a five and then the control system recommendation from the controls guys is to go with the flap control system. So the key technical contributions of this work. It's one of the first that really really closes a DB control system with Hardware visibility and guidance. Can controls performance? It's a really big deal. I'm really proud to to be a part of this.

C

To be a part of this effort, there have been a the other studies and some assumptions made like. Oh, we assume we can control roll or we assume we can do this. So we we assume that something will take care of it, but we, you know, kind of run the gamut and go through the start. To finish what can be done?

C

The impact is this enables for the applications of inflatable or mechanical the playable intro vehicles for science mission and high missions, high mass missions to Mars and beyond this tool set can be applied to any vehicle or control system right. This work has been done, it's not just for TVs. You can go through the process of doing this for any vehicle control system type. You have a question.

C

I I'm unaware I, don't know so I'm, not a structures person, so the base yeah. So your question is: are any rare metals used in the construction of spacecraft or deployable entry vehicles in general?

C

Yes, he might have an answer.

C

Yeah beryllium, he said yeah I, don't know so I'm, not a structure. That's why I'm a controls girl, not a structures, person I, don't know what material will work or break. But you ask me a controls, question and I hopefully have an answer for you, but but I don't know. So that's an interesting question. There's a lot of work on the TPS thermal protective system side at NASA, Ames, Research Center. So the big thing with these vehicles is basically withstanding.

C

The kind of thermal environments of these vehicles are subjected to and we have arc jets that do a lot of testing and the big one that we use here I know is Heat hae T and even that is an acronym, no kidding so yeah. So that's the big thing with us. We really really like kind of pushing the frontiers and boundaries with lightweight enough, but thermally like resistant material. Yes,.

C

C

Yes, the thermal protective stuff I talked about is actually like subjecting it to those thermal conditions that it will experience, and then there I mean there are a number of studies that will show you how doing some work in like simulation with some scaling factor depending on Reynolds number and things like that. But what we did here is a python-based simulation for the control for the controls. Team basically see I'm a MATLAB girl so and MATLAB is a NE mount. My people in here yeah I'm, like the my life, is easy.

C

Matlab warrock stimulant Horrocks, but this was a python-based framework and simulation. So in simulation you can do sims, but then future flight test staying in future, like suborbital flight tests, are ideal next steps for this project. If we get some additional funding, so if you have money, let me know you know we'll take it, but it's it's it really! It's a cool! It's a really really cool project with some really really exciting, and this by the way this is an early career project.

C

Did I say that all like the lead, the purple, the primary inverse to give the principal of this investigator and the team, like the core team, everyone leading all of the disciplines is an early career person. I started at Ames well, less than four years ago, I got my PhD in 2015. These are early career people that you know you give them money given the opportunity and we're ready to think outside the box. So if you give me money we'll take it / any government regulations. Yes,.

C

I can't hear you can you repeat that question.

E

E

So for project like this, how does NASA decide whether something needs to be tackled in house like in Ames versus just hiring somebody else to do it like Boeing? Yes,.

C

So this wasn't a project that NASA said: Oh has to be tackled in a house. Nasa actually gave the opportunity was the space technology Mission Directorate. That said early career people put your idea forward, so we weren't limited to this. Their request for information. A number of calls and proposals that range from the most I mean a very, very diverse thing. So NASA doesn't really restrict anyone. We weren't we're required to do this. We just wanted so we're interested, so NASA doesn't restrict their employees their researchers. Neither do they restrict outsiders as well.

C

So there are many opportunities in many ways you can do something on the outside. You can submit a proposal. You can answer there, just a whole number of ways and I share. All of this, like as much as I can on my Twitter and Instagram, like no kidding I find something I post that I share it. There Wendy underscore Colo. So if you have kids that are like how do I get an internship at NASA, how do I do cool work at NASA? There are opportunities out there and I share all of this like there's.

C

So many ways to get in and to do really really exciting work, I'm going to just kind of run through the summary of the key technical contributions, closing an oval control solution that makes a symmetric vehicle configuration scripts, controllable and demonstrating the feasibility for vehicles not previously considered. You know on traditional entry vehicles that can better serve mission needs versus traditional systems.

C

So we identified this hundred percent non propulsive entry control system. We have built this sixth off simulation test bed that will be completed the summer. The project ends in May June of this year and we are looking forward to redesigning the flight controller architecture to enable alpha-beta tracking and obtain full-on funding for hardware prototype being demonstrated in a suborbital test flight in subsequent years.

C

If we're able to fund this and keep on doing the work- and here are the references to the papers, so you probably want to take a picture of this because there's like additional information of the different disciplines in here I'm, going to leave this up and then.

C

Yeah, please take your pictures, there's so many papers, especially audibly. We had a special session at an ablai in January at an oblique itec in Florida, this January and if the pictures are done. That brings me to the end of my presentation: what okay, okay, so yeah he's saying. If you have questions too, please go up to the mic and thank you for your time.

F

Okay, you mentioned in your summary that there are some mission requirements that this extra manoeuvrability should help. Can you tell us what some of those are sure.

C

Yeah, like a sample lunar return, actually, which is which is what we're looking at so, for example, if you imagine the Artemis program and the Gateway that is supposed to be kind of semi-permanent I mean Danny can probably speak to this.

C

Imagine being on that gateway and being able to lunch something from Gateway but not requiring a heavy like an actual capsule. But you want to bring something back to earth. You want to bring the sample they've gotten on the moon and now you're on the gateway. You want to be able to launch it from the Gateway back to earth. That's like the perfect one.

C

So you can scale the size of this deployed will interview and in fact, when we started out where one plus meter was scaled, it now we're working with something that's like I, think 2.5, so they're different scalings and these architecture works. So a sample return is like the perfect one, a sample not non astronauts. They are not samples.

C

G

You know when you were talking about the alpha and beta or the Sigma, and you are actually in a two dimensional model and I was wondering if you had worked with a three dimensional model to begin with, would that role perhaps surfaced earlier?

G

You could have done the model and then at some point, set roll20 and perhaps come out with those values that you know. The five degree angle that you were talking about, I'm.

B

Just wondering yeah that the.

G

Mathematical model might have been broadened, yeah.

C

It's already mentions right: we were actually working with a six degree of freedom, six Dolf, because.

G

C

Translation X, Y, Z rotation, yeah.

G

That's what I just thank you. Next, one yeah yeah.

C

And so that's what we worked with and that's actually what demonstrated this role you're coupling that's how we were able to find it because we're working in multiple dimensions- okay, but but to kind of answer. Your question, the you remember, I talked about there's like static derivative stability there.

C

Yes, they can do beforehand to see that can provide some kind of indication to there's very, very Lourdes or low fidelity analysis that can be done in terms of looking at your CL beta, so C L beta is like the coefficient of roll moment dependency on fried slips. So, as you vary your side slip, the roll moment coefficient changes. The roll moment has that dependency on CL beta. You can look at the magnitude of s CL beta, so the magnitude of the CL that's generated by the flaps.

C

So if you have a roll moment dependency on flat one, you can call that, like CL delta, one or something you can look at those magnitude, C seal Delta, one or the roll moments generated for the flaps are comparable in magnitude to the CL. That's generate from the base, aeroshell site slip and, if they're feasible, if they're close enough, you can kind of say: okay well we're doable, but that CL beta from the base arrow show was pretty large.

C

So then that flap design, the flat design show they're wearing the way the flexure design were not to get a seal to counteract that see elevator. So we have to change the flaps, which leads to his point about twisting them.

G

Yes, yeah yeah exactly so when you were doing all those comparisons and I saw a lot of deltas, so were you watching the deltas and as soon as those deltas got to a certain limit, you were saying to yourself: okay,.

D

G

Were you also looking at perhaps intervals like it? This interval, these deltas are okay, this interval mm-hmm, and maybe this one they're really out of whack. Yes,.

C

So so that's like a two-part questions, the deltas, which are the flop. They have a saturation limit which is plus 20 minus 45, go beyond a further than that, even if controls wants to aerothermal wooden lettuce. The second point about within a certain range we're good lends credence to that envelope that I should for alpha-beta. It's like okay within this range you're good, but it's that range good enough for God inch, trajectory precision targeting and then what, if something happens, and we get in an uncontrollable roll mode. It's that's something we want to play with.

C

So you know when the conservative angle and said like it: okay, let's go ahead and do Bank, but we want to be able to expand that envelope and show that we can work outside of that envelope and rather expand the envelope and be able to generate some sort of real moment control yeah. So we did both and then some interval you're good, and then we have saturation limits on the flaps. Thank you. Thank you.

H

Thank you and I'm glad to hear that they're funding the young-young, because I know they're trying to do that also in the medical field, because there it takes years by the before they can run their own labs. So.

B

It was good it.

H

Sounds like it was your college education. Some of the funding was the AI double-a, some it's someone who contributes to that I'm glad to hear that yeah.

C

Yeah, it was primarily the Air Force Research Lab back okay.

H

Yeah yeah through.

C

The office of scientific research and through the air for the lab itself at.

B

Wright-Patterson.

C

Ohio summers they're right back, yeah, yeah.

H

Okay, my question has to do with really where you fit in the bigger your mission. Phase fits in the whole picture and I'm just guessing since I. Don't know the whole thing that you're probably talking about some orbital vehicle, that will then release this probes, yeah the lander and there's a phase where it comes off and there's a I know that you're studying a particular phase where you've come up with the flaps work, the best. Obviously it sounds, like you hand it over to someone else to do the parachute.

C

Yeah well, what I'm.

H

Wondering about is when the vehicle first comes off the host vehicle. How would it be controlled that way and I'm assuming that mysterious to thin for flaps to work? My thinking about something like how the Space Shuttle is.

C

H

In space and then it even had a period where it used both and then, when it landed, it only used a flap or.

C

H

C

Yes, so interesting question that phase a spin stabilization right when it comes right off the mothership. If you can kind of consider that, but it's typically RCS thrusters that I use this to stabilize and get some spun out, it gets spun exactly and so it needs to stabilize and then begin its entry. And we that's not our focus, but it's actually good. It's it's.

D

H

Very interesting thing.

C

To see if that is a regime that these non propulsive control configurations can control, so maybe I can get an intern to.

H

C

Exactly exactly.

H

But in the thrusters to spin it up are those coming down with it. Are they on earth they were? Is they.

C

Come down with it and they were you, they're also used for the propulsive RCS.

F

C

Exactly exactly, but they might work because remember I showed a gene C activation. We are at eleven point five, where the minimum required for, but that was entry was like five degrees per second, so it could work I'm, not sure, but we have an investigator.

H

Yeah, well, yes, spin civilization uses RCS, that's a good simple way to do it. Yeah.

C

B

I

How do you know where you are in space at the time? How.

C

Do I know where I am in space space? How do you know where you are so like me or.

I

The space, if an.

C

Astronaut in space, how do they know where they are Oh, an astronaut in space I, really really hope.

C

We can keep track of her astronauts in space so most times they're on the International Space Station, and we know exactly where that is orbiting our earth every 90 minutes other times, I mean previously other times, they're they're still attached to the space station in some regard and tethered and doing all these spacewalks all these cool things that they doing outside of the space station for like seven hours and end and then we've landed on the moon too, and we were watching them the whole time.

C

So, but that's a good question it comes into when you I mean, if that's what you're interested in when you're older. Now you want to be in navigation, so guidance, navigation and control navigation is where exactly? Are you so remember that GPS, yes, satellites yeah?

C

So that's how we know where you are.

B

D

The their control software I'm short, but not that short, does the control software account for loss or jamming of one or more of the flaps masses and or jets, and if so, what would be the maximum number of loss or the minimum required to maintain the control yeah.

C

So the multi-input multi-output linear quadratic regulator, design you can actually set so there's I, don't know how much we care about this. So you go through that process of you know. You have your nonlinear equations of motion and you linearize you get through your linear system and then you're trying to find this. U equals K X minus X desired that K gain, and then you plug it back in and I said your balance in objectives. Remember when I said your balance and objectives who remembers, but you can get here fast or a little slower.

C

The way you do it in the control is through two matrices: two matrices for the lqr aq matrix, which is telling you how you want your states to perform and you our matrix, which is telling you how much of a control effort to use. So if you put a waiting number like an entry in that R matrix, that's really high, so they say for the like. You can imagine this our matrix as a diagonal matrix right.

C

So the first one is flap 1 flat, 2 flat 3, all the way to flap a if I put a really really high number here. It's gonna tell my control design that don't use this control surface like barely. Is that don't touch it so through that you can actually check? If something happens, are we able to still still fly and achieve the guidance trajectory?

C

There won't be some trade-off, of course, in terms of the performance, but you can do some of those studies beforehand and actually check, because you have those eight flaps for okay, maybe redundancy or increased control authority, but how low can you do it? So it depends on what it is you're actually trying to achieve in terms of the guidance trajectory. How fast are you trying to achieve it, but you can do some of those tests beforehand and, like basically say no we're good. We did some and for the angle we don't need all flaps.

C

We don't need all eight flaps for Bank angle. Control. Remember, would design those for alpha beta and we didn't eat them.

C

C

No, so we're not doing shape morphing, even though that that is, that is another part of controls, right shape, morphing moving masses, but the moving messes here is kind of a rigid form Rican, it kind of changed the shape of the vehicle, but we're not doing that. We're assuming that you know it's this, this shell, that we're not we're, not changing the shape for, but you can do some of that.

C

Adaptive control work and it's not a fixed lqr, where your mass and inertia properties are changing with some of those moving mass equations, you can so you might wrote some equations I took them out for brevity and ease for this presentation, but this equations can get really really like almost intractable cuz. Now you have your masses moving your masses accelerating, so you have mass positions of like one to one through eight positions, velocities and accelerations- and this, like your states, blow up from like what HR like 31. So you can.

C

You can kind of do some of that, but we're working with like a fixed mass and like inertia here for like what I set for the flap. So we're not doing shape morphing. Now, no, oh yeah! The big thing is you: can you can check beforehand and see if you can put a weighting on any of those or multiple of those swaps and see how well you are able to control yeah? It's pretty. It's pretty cool right.

C

What things this is cool, yeah everyone! It's pretty neat.

B

I

So I assume what you're doing right now is just a feasibility study. What what does a development phase look like? What are the different major milestones like you? You have some hardware. You fly it or and in a rough timeline for that, it's a yeah.

C

So, ideally, to be able to carry it forward. This is what we want to do. We want to go to hardware prototyping right. We already did a prototype of the flat designs and we do what demonstrate when people come to Ames. We can show that as well, but did the hardware prototyping develop a test flight vehicle to support of this capability and then feed for technology that others that will need it? That will advance?

C

You know the exploration of Mars and the other things that we want to do so right now, we're primarily heavily in the software design and development phase and, like you said, a visibility study, but this is work that we want to see actually go forward right, even if it's not what those who want to see that go forward.

C

Yes, so the funding ends mate June of this year, so that's it yeah. So unless you and evil that's I'm kidding, but no we're so we're doing somewhere to see if we can get some follow-on funding to you know demonstrate this.

C

There was some orbital flight tests for the Adept, like the baseline, pre baseline vehicle a year or two years ago, and there are some results and that public information as well on Iaido bleh but yeah. So, but if you find something to hop on, we can go ahead and do. But this is just primarily software. That's taken this much extensive effort. You know from the team from the team as a whole, but it'd be good to do some part of it prototyping and then see it back till we see it fly yeah.

C

Okay, any other questions, yes, which.

I

Is worse from the controls perspective, direct entry at Mars or lunar sample return.

C

C

From a controls perspective, which is worse, that's yes, so that's an interesting question that that I can't answer here's. Why? Right, if we're doing FCS, if we're doing flood control systems and we care about our dynamic pressure, we care about the kind of control authority that we can get from our aerodynamic control surfaces.

C

If we're doing RCS and you just have thrusters and you can go ahead and you know work with that- you probably don't really care, but I do recall that the sample lunar return was chosen forward like the stress loads, but it wasn't done in comparison to Mars. You know it might have been done in comparison, a like going there versus coming back so I, don't know, I, don't know. That's an interesting question like basically I would first probably look at like characterizing the environments.

C

I mean it probably is hard to do Mars, because how well has that environment in characterized right in comparison to to our atmosphere? Right? We know ours pretty well, we should would live here right, so it'd probably be easier. If you have all the right information, then you can design something that works right. If you have the right information, but when you start dealing with uncertainties, particularly atmospheric uncertainties, aerodynamic uncertainties, then you have to start to design with a wider margin and it's something to keep in mind.

C

You just I think the uncertainty is probably come into play there. So I don't know. Did that answer your question? It's like yeah. If you know, if you know it all well, then you can make an you can make an informed decision. You can see this is easier than that. But if you don't know well enough, then thank you.

B

Okay, any other questions going going gone.