Request Generic Robotic Lander

[WolfAngriff]

Hello everyone.

As I like to do custom missions with near-tech launchers/payloads, i've often used the Chapman Probes ( https://www.orbiter-forum.com/resources/chapman-modules-v-4.2019/ ). This family is realy great and easy to use, but limited enough to bring constraints like mass and Delta-V. But, AFAIK, there's no unmanned artificial lander to play with which brings the same good things : 2 or 3 cameras, a simple HUD, a bit of animation, a nice design, enough thrust and Delta-V but not too much, a realistic mass.

Of course landers are much more complicated, as they need touchpoints, RCS rot and trans, a more complex design to mimic scientific instrumentation. Even more for optional animated legs, solar panels, scientific stuff, etc. No need to have wheels or tracks, the goal is to land on a target, nothing more. Plus there are two versions needed : atmospheric and non atmospheric landers. The first one needs a heatshield, a parachute and/or airbags, etc. But it could be the same lander, just two different versions.

But i think it lacks something like that among Orbiter addons. I mean : a generic near-tech vessel, usable via Scenario Editor, which can fit under almost every fairing, and beeing able to land everywhere in the solar system. Like the Chapman Probes, except they don't land anywhere.

This request has two goals : the first one is having a nice new toy to play with, of course. The second one is seeing if i'm able to understand what could be the demand from end-users' point of view about Orbiter, and what devs' point of view could be about it. This second part takes place in a much wider idea i'm working on, so the negative answers are VERY important for me, as far as they are explained.

Thanx a lot for your attention.

 

[Urwumpe]

How large do you want it? Can you sketch out a envelope? What is the mass limit?

 

[WolfAngriff]

How large do you want it? Can you sketch out a envelope? What is the mass limit?

Let's say something in a 2m x 2m x 2m cube max without heatshield, with deployed legs. For the mass, let's imagine 100 to 200 kg for the scientific platform and all the stuff. More if using RTG, which could be wiser to reach long range targets, and more simple to modelize. Fuel tanks and engines needed to deorbit and land to be added, depending on physics. I think it could weigh something between 0,3 and 0,5. metric tons for the whole vessel. Added to a Chapman Probe weighing 1.2 t, we could have both vessels at 2 to 2,5 t together without heatshield. So the lander and the orbiter will be able to mimic a complete scientific mission. I don't know exactly how heavy could a heatshield be. Engines should be placed on the sides of the lander, so they could work with or without heatshield keeping the same lander, avoiding a crane... Yes, I know, that's not too much realistic. But it's more simple.

But nothing mandatory here. To give a scale, i'd say more than a Viking lander, less than a Curiosity crawler.

My favourite launcher for custom orbiter missions ( https://www.orbiter-forum.com/resources/themis-a-launch-vehicle-1-0.5416/ ) is broken, so i'll choose the launcher depending on the payload's mass and the target. Kulch's Energya with the space tugs could always do the job anyway !

I don't know how much complicated it could be, but it would be realy a plus if it could be spawned via Scenario Editor. I know how to make custom missions with .cfg, guidance and .scn files, but it could be better for further possible proposals.

 

[Urwumpe]

No problem, I rather meant the envelope for the launch configuration, assuming everything that doesn't cover square kilometers later is fine. For example, some might mean small = fits through the docking hatch.

No problem if its DG tech and not fully realistic technology?

Scenario Editor isn't a big problem unless you need special configuration tabs for it. In that case, people without C++ skills would be hindered to contribute.

Sounds like a nice little diversion project, maybe I'll try producing a proposal prototype there.

 

[WolfAngriff]

No, not fully realistic. Let's see it as a serious toy, usable by a beginer orbinaut. No energy managing or CoG balancing, but at least a downward camera, prograde camera, and a horizontal one as to make nice images of the surface of the planet.

I don't know if it's "special" configuration tabs, but heatshield ejection and chute deployment for atmospheric landing seems inevitable. For non atmospheric, just the standard fonctions : engines, RCS.

Thanx for your attention Urwumpe !

 

[Urwumpe]

Is it a problem, if only a small number of parts are re-used between vacuum and atmospheric lander? Would make the whole design a lot easier.

In that cased, it could boil down to a common similar user interface (Maybe something AMSO like), while the actual probes are allowed to be largely different.

I would then focus on keeping main spacecraft bus and the science platforms similar, but equip them with fully different landing systems. IMHO the vacuum lander would likely need some handycap there, since it needs a lot more mass for landing than the atmospheric one.

 

[WolfAngriff]

Well, i didn't imagine it could be easier to use different parts ! If it's easier, it's better ! I guess you've understood that both vaccum and atmospheric should look like they're from the same agency with heavy economic constraints, so trying to use as much common elements as possible. And if the textures are close to the Chapman Probes, that would'nt be bad. But it can be seen as a collaboration between two agencies. As far as it's not too heavy nor too big, nor too complex, it's good.

I think i'll soon open a thread about what this vessel could be part of, in a much wider idea. But first i imagine it as a usable vessel for people who want to land on planets and moons the way they want to, with a nice "all terrain" lander. If the orbinaut has to learn that a vacuum lander and an atmospheric one are not the same vessel, with different behaviors but same interface, the goal is reached. When i've spoken about the same lander for two versions, i thought it would be easier to do... It's the first time i post a request, and well... it's not so easy...

If you're OK, i can send you a short recap of what i'm thiking about via MP. It can give you more about the context.

 

[Urwumpe]

Well, i didn't imagine it could be easier to use different parts ! If it's easier, it's better ! I guess you've understood that both vaccum and atmospheric should look like they're from the same agency with heavy economic constraints, so trying to use as much common elements as possible. And if the textures are close to the Chapman Probes, that would'nt be bad. But it can be seen as a collaboration between two agencies. As far as it's not too heavy nor too big, nor too complex, it's good.

Well, I'll just do some prototype. If its a bad idea, well, back to the drawing board. If not, next iteration, fixing the bad things and improve the good things. If somebody could then provide better meshes to me in the next steps, fine. If not or somebody else creates a better add-on, also fine.

Just stay in motion.

 

[WolfAngriff]

Good for me.

Thanx again !

 

[Urwumpe]

Small news: After some brainstorming,trying to get my thinking out of the box, I found some possible configuration for a robotic lander that could be used for both atmosphere and vacuum, fits into the 2x2x2 cube as desired and might not be overly fantastic.

So, this is what I have found in my brain, a small, relatively flat semi-elliptic lifing body shape with a relatively large scientific payload deck below a moving payload door (marked green). This lifting body is 1.2m wide right now, 0.3m high and 1.5m long (the reference length for the design).




To this basic shape would come a reverse tricycle landing gear (left, right, aft), two AOCS pods on the rear (Attitude and Orbit Control System) and a rectangular solar array on the rear, that can be retracted below a heat shield. The vertical landing engines would be deployed from inside the aerodynamic fairing after reentry or for initiating powered descend in vacuum. The payload door would have three states: Closed, Partially open and fully deployed. Right now, its shown closed, for partially open, it would move up and forward, exposing forward landing gear, descend engines and the high gain antenna. During cruise, it would also be partially open, allowing to use the high gain antenna for long distance communication. After landing, this payload door would be moved fully forward and rotated by about 90°. If it fits, I would install a small experiment boom at the aft end of the door (then the top of the door), which could carry a small weather station for atmospheric landings. The large door could block some part of the horizon after landing but I think its not too bad, especially if the camera would be mounted on the robot arm or a special scientific camera could be carried as tool by this robot arm. If using an autopilot, this autopilot would always rotate the lander in a way, that the solar array is pointing towards the sun at noon afterwards (eg for northern hemisphere on Earth: Door points north and solar array points south)

In the rear, between the two AOCS pods, would be a rearward facing camera, which rotates downward during landing gear deployment. The only fixed element on the scientific payload deck so far is a robot arm to allow manipulating experiments and collect samples.

This here is based on the assumption to allow using DG-tech technology, so I had some more artistic freedom there - it can be reused, might even be able to lift off from smaller bodies again multiple times (e.g. Moon, Ceres). It is not supposed to do large orbital maneuvers like a translunar injection, but could cruise by itself over multiple months. For more realistic technology and lower specific impulses, I would likely need to specialize more and create multiple different landers. But with DG-tech, I would prefer giving it a more clean and more DG-like look.

So, what do you think - within the specs for your request, or too far out of the box?


If OK, the next step would be fitting engines, solar array and landing gear to test how this would look like and modify the dimensions of this basic shape to better fit around those parts.

 

[WolfAngriff]

Hi Urwumpe !

Well... This is clearly not what I expected. But such a good surprise ! Of course it's OK for me !
One single vessel able to do all possible landing missions, that's the best solution.

Thanx a lot !

 

[Urwumpe]

Hi Urwumpe !

Well... This is clearly not what I expected. But such a good surprise ! Of course it's OK for me !
One single vessel able to do all possible landing missions, that's the best solution.

Thanx a lot !

I also started looking at a capsule like shape (a bit like a Dragon 2) - but the big advantage of a capsule turns in a rather annoying disadvantage in this case: Lots of internal volume per heatshield area when you actually want a large enough exposed area for experiments.

Next step then: More details.

I still don't really like the rather large door, its possible that I will optimize this a bit more.

 

[WolfAngriff]

When i first thought about it, i imagined a robot with four legs, with one version without, and one with heatshield. I've never thought about a glider, but it's so clever !

Why not simply eject the door ? It could be seen as a seismic experiment. It could be "recorded" via the landing gear when the door falls on the floor. If the door is smaller (round shaped ?), maybe it could give room to a stowed antenna (DG like) out of the door's area, which could be deployed first when the vessel is landed. The way i imagine such a mission, the lander/glider will be launched with an orbiter, which would work as a communication relay during deorbit/reentry. So, i think that a small static antenna or a pod with an aerodynamic shape on the rear top of the vessel would be sufficiant to communicate with the orbiter. After landing, the high gain antenna does the job for direct communication with Earth for piloting the experiments, as the orbiter does other observations and experiments while orbiting the celestial body. As stated before, don't worry about the orbiter, it already exists. When all is checked after landing, then the door is ejected and the other experiments can begin, seismic experiment first. Hmmm... But the door becomes another vessel attached to the lander. I don't know if it's less or more complicated than a complete door animation.

Well, those are just suggestions of course.

 

[Urwumpe]

Why not simply eject the door ?

Well, I would hate to have the door somewhere, blocking the way to something interesting below or behind it. So, it would need to be discarded far enough away from and landing site. Also, it would make reusing the lander harder. So, I prefered to keep it, but of course, its impact would then need to be minimized. One option I think about is too fold it like the engine doors of old trucks - not sure how it is called. Looks like a letter M, when viewed from front. since the top part of the door is fairly flat, this could give it a very low profile. Also it could look almost antique, if you have such a probe on your workbench with one of the doors opened like that for maintenance...

 

[WolfAngriff]

A Space Ford Model T... Yes, it could look cool.

But the M shape forbids the use of anything in the longitudinal axle of the vessel... It needs one more articulation, so it increases the risk of malfunction. And it increases the risk of ripping the doors off during reentry if we think about aerodynamic constraints.

I was thinking : open in two parts, like the space shuttle cargo doors ? It gives opportunity to mount solar panels on the inner door's side, providing more energy for missions beyond Mars orbit, and foldable in case of dust sorms ? And if it's opened with a final negative angle, it doesn't block the view from the tool mast. Yes, i know, way more classical.

 

[Urwumpe]

Well, I wanted to have a central mast running from front to back anyway, so the main problem would be keeping the door latched until its deployed. If doing proper engineering here, I would need to fit the door onto a frame to keep it latched at all ends until it is folded away. This mast would then be available for experiments or additional cameras for observing the operations of the robot arm.

Doing it like the Space Shuttle would be more annoying, since it would block a lot of area below the lander from access by cameras and robotic arms. The idea is, to have as much area as possible within the working space of the robot arm accessible - ideally the robot arm could even move a camera or experiment BELOW the lander. A telescoping cover would be another option, but then I would reduce the height of this door more and give landing gear and landing engines extra doors that translate out- and downward.

 

[WolfAngriff]

Oh OK, you speak about an arm AND a mast ! I understood only a mast. Yes, with a robotic arm, those big doors will become more annoying. It will put all the surface under the vessel in shadow. Not good. With those M shaped doors, you can put arm and mast on each outer side of the science bay ? The mast deploys from front to rear, and the shoulder of the arm fixed at the front angle, and it deploys from rear to front... I don't want to look controversial, i'm just trying to provide hypothesis.

As to keep the mast on the central axis, a part of the vessel's envelope could be sticked to the mast. The mast could be freely deployed at the cost of some space between the doors, before they're opened, but as the mast is a thin stick, it's a question of 10, 15 cm. The cameras could be stowed along the mast axis ( x ), and rotate perpendicularly to the mast ( y ) when it's deployed to save space, and keep the envelope part sticked to the mast as a rectangular shape, tight and long.

 

[Urwumpe]

Oh OK, you speak about an arm AND a mast ! I understood only a mast. Yes, with a robotic arm, those big doors will become more annoying. It will put all the surface under the vessel in shadow. Not good. With those M shaped doors, you can put arm and mast on each outer side of the science bay ? The mast deploys from front to rear, and the shoulder of the arm fixed at the front angle, and it deploys from rear to front... I don't want to look controversial, i'm just trying to provide hypothesis.

Yes, in that direction - mast should go into the front, the robot arm shoulder to the rear. This way, the widest part of the spacecraft would be closest to the shoulder and the arm could reach around it.

As to keep the arm on the central axis, a part of the vessel's envelope could be sticked to the mast. The mast could be freely deployed at the cost of some space between the doors, before they're opened, but as the mast is a thin stick, it's a question of 10, 15 cm. The cameras could be stowed along the mast axis ( x ), and rotate perpendicularly to the mast ( y ) when it's deployed to save space, and keep the envelope part sticked to the mast as a rectangular shape, tight and long.

I think it would be better to move the robot arm off center, closer to the edge, so it can easier reach below the lander from that side. Of course, the other side would then be harder to access. But I'll test this later.

I'll produce a more detailled prototype concept, maybe it is more clear then, how the things should be moving and where they are.

 

[WolfAngriff]

Sorry, i mean the mast, not the arm, between the doors. And the robotic arm off-centered. I've edited my post.