The Kerbal-ladder engine. The lightest Eve ascent vehicle

[Tw1]

For 2019's update, skip to this post.
This thread documents the development of a space capable ladder-force engine.
For a while it was known as Attempting to voyage through space- the Kerbal-ladder engine. An experiment/adventure. 

 

It's time for another edition of attempting to go to space!

Where my bored rocket scientists try unconventional, yet maybe-possibly useful ways to put kerbals into space.

Kraken drives are all well and good, but today I tested a potentially unlimited source of delta-V. A Kerbal, and a humble ladder.

A while back, I attempted a the "Kerbal powered aircraft" challenge, where the only source of thrust your plane could have was a kerbal, pushing against something while climbing on a ladder. Apparently Newton's third law has some limitations.

Though a plane is nice and stable, with wings and all that, all that extra weight is using up precious thrust. To get to space, I decided to go smaller.

There, that aught to do it. Now, just got to get a kerbal up there, and away we go.

.

Excellent, we are gaining altitude. And it's such a nice day at the space centre

Hang on, that trajectory is not ideal.

Oh dear.

Clearly, this design had some problems. The most obvious was the imbalanced thrust from the kerbal. Adding more control systems would just weigh it down. Instead, a more refined design was necessary.

To counter the unbalanced COM, some changes were necessary.

I first tried moving the RTG.

However, this was not enough. Extending the structure using cubic struts tended to leave some imprecision, and this thing needs to be precise.

My next test used the rockomax micronode- a part I don't think I've used before. While testing on the pad, everything looked good. Halzor's head seemed to be pushing more or less where the COM was.

However, there was just one small problem. Balance.

Without thrust from a kerbal, this structure tipped over at the moment of release. Not intended functioning.

Perhaps if I didn't have the delay between firing the decoupler, and switching to the kerbal, things would work out. I tried using KAS plugin's grab function to pull out one one the struts, so there would be no need to switch back to the ship. But this did not work well either.

Perhaps a different approach is needed. If the structure keeps tipping over, why not make some launch stabilisers?

Added one. Did not have desired effect.

Added three.

Vessel and kerbal were trapped.

So, supports aren't the way to go either. I contemplated using the proper stability enhancers, or mounting the structure on a radial decoupler, but as it is so light, these would probably send it flying. A third solution came to me later, at dinner.

Stabilising legs!

However, this tended to explode after decoupling.

Having not had much luck with vertical take off, I went back to my plane. The problem that prevented it from going to space had been a lack of control authority when in the upper atmosphere, so I added a few extra probe cores to give me more control. I also gave it the ability to drop its wings when they become dead weight, rather than giving me useful lift. Landing can be thought about later.

Unfortunately, it soon became clear that this version of the "One Kerbaglider" was not going anywhere fast. It was too heavy and slow, and kept pitching down when I switched to Halzor to provide thrust. When wingless, it was even worse.

You will not go to space today.

However, these experiments showed me enough to come up with a much better design.

That's for next time.

Edited August 4, 2019 by Tw1

[Geschosskopf]

Hehehe, that's a laudable contribution to Kerbal Science! All this reactionless drive technology at our fingertips, yet we struggle to use it

[Tw1]

All this reactionless drive technology at our fingertips, yet we struggle to use it

Ah, but wait 'till you see what happened next!

Previous designs had two main issues- lack of deployability, and unbalanced thrust. In my final design, I took a different approach, and built as if it would never need to be attached to a pod. Then, I linked it to a pod radially, using docking ports. I also cut down on mass by using solar power.

To prevent the docking port making my spacecraft unbalanced, I used KAS to pull it off, as you see here.

And then.. basically, it worked.

Initially, there was a certain amount of sideways velocity, but soon Halzor was pushing that thing straight up at a rapid pace.

Much to his surprise, I even managed to do a pitch over. Headed north, as the thing was already slightly pitching that way.

He's really committed now!

The map view's trajectory predictor was quite confused by this contraption, and wouldn't give me a proper apoapsis reading for either Halzor, or the ladder thing. I had to make a guesstimate, and ended up with an apoapsis of about 150 km or so.

Apon reaching that apoapsis, Halzor did his best to circularise. And we did it.

First kerbal to orbit without any engine at all!

Time to try the landing. By pushing retrograde, Halzor slowed the craft into a suborbital trajectory.

Here, I observed that keeping the ship pointing retrograde helps keep the kerbal on the ladder.

Unfortunately, I did not manage to land it. Revert flight time.

That design was pretty limited. There was no timewarping apart from the 4x physics warp, and no quicksave or autosave.

Clearly, to be something useful it had to be improved.

Improved:

Not only does this design have a seat and parachutes, it deploys without needing KAS grab. It is all stock, apart from the mechjeb unit which I didn't end up using much anyway.

Compared to the previous version, this device* climbed slowly, but was still within acceptable speeds for rocket flight. The thrust alignment still isn't perfect, there's a little horizontal drift.

Look at Halzor, working so hard at that ladder.

*I'm somewhat adverse to calling it a ship or vessel. It has no engines, with no kerbal it's just a frame with reaction wheels.

It's hard work for a kerbal. (This is a very short gif, he was actually moving up pretty constantly.)

Pitch over had to be higher and more gradual due to the reduced TWR. I had to rotate back upwards a few times in order to make sure I'd clear the atmosphere. Throughout the launch, I made sure my panels were pointing lined up with the sun.

Eventually, the map view worked out what it was doing and gave me an apoapsis.

Now, it is time to test the seat. Boarding is very easy, it can be done while still on the ladder.

Look how happy he is!

At apoapsis, it took a small amount of EVA fuel to move back to the ladder. It's very important that kerbal and ladder are aligned before moving in to grab it, or you waste fuel bouncing around.

Then, I circularised.

But I didn't stop there.

We're going to the Mun!

Edited February 20, 2014 by Tw1

[Geschosskopf]

Ah, but wait 'till you see what happened next!

Damn, that's impressive! Really puts my Bill-powered rover in the shade . Now I know how I'll build my Eve SSTO lander

[Tw1]

Geschosskopf said:

Damn, that's impressive! Really puts my Bill-powered rover in the shade . Now I know how I'll build my Eve SSTO lander

Just saw that thread, I'll have to go have a look.

An ascent from Eve might be possible- I had a little difficulties with landing on Kerbin- got one last bit to write up here later- but I suspect they could be overcome with some more refinements, or by adding a stageable landing platform.

The real question will be if you can get enough TWR with one kerbal. It would be interesting to see if multiple kerbals can be used via EVA followers, but that plugin was glitchy for me.

Edited August 3, 2019 by Tw1

[MarvinKitFox]

Stairway to Heaven!

+1. Heck, make that +googolplex to you

[FanaticalFighter]

Holy god. This is the best krakendrive ever. The BEST. EVER.

Sir, you have officially won KSP.

[geb]

An accent from Eve might be possible

It is. http://imgur.com/a/01YgQ#0

This is the same bug that was used to power the FTL Egg, way back before the great forum derp. My own Eve flight didn't have any control on the ascent vehicle, so Jeb had to glitch up into a high suborbital trajectory then circularise on jetpack. It works though.

[Tw1]

It is. http://imgur.com/a/01YgQ#0

This is the same bug that was used to power the FTL Egg, way back before the great forum derp. My own Eve flight didn't have any control on the ascent vehicle, so Jeb had to glitch up into a high suborbital trajectory then circularise on jetpack. It works though.

I'd heard someone had used that thing to get of Eve, nice job. But I don't think it's the same bug, though there may be some relation. Ladderlift is far more controllable, it only happens when you are pushing. It seems to come from whatever mechanism they use to move a kerbal along the ladder.

From what I've seen, the FTL egg is more related to the kraken drive, though there's something there about ladder physics too.

[geb]

The FTL Egg is somewhat controllable, though not in a useful way. It only activates if you try to climb your EVA kerbal along the ladder. That's what made me think it was the unbalanced ladder forces.

I assumed that when you climb up a ladder, the kerbal is just moved, not experiencing a force, and so there's no counterforce on the ladder.

[Tw1]

I'm Back! And I've got a report to finish.

Behind the Mun, Halzor performed a "push" to bring the "vessel" into circular orbit. Then, I eyeballed a burn to make it loosely equatorial, and recircularised.

Landing was tricky- I've got to used to using maneuver nodes to plan descents. But as I didn't know my TWR, and maneuver nodes vanish when you switch craft, this was done seat-of-the-pants style.

I canceled my horizontal velocity,

And came down vertical.

I hovered above the ground for a bit, as imperfections in the "thrust" alignment ads a horizontal component even when pushing straight up. I had to adjust to compensate.

And then... Touchdown!

Made it to the Mun with no fuel at all.

(Unless you count the EVA pack fuel used to move from seat to ladder.)

Halzor spent about a day on the Mun.

Then it was time to return to orbit.

However, we're not going home yet.

We're going to Minmus!

Transfer was tricky. Orbit plane matching was done by flicking back and forth between the main view, and map screen. The slightest bump too much, and I'd loose the encounter.

Eventually:

Landing on Minmus was easy. Knowing I had plenty of TWR, I put Halzor and "ship" on a descent trajectory,

And landed safely on the slopes.

You might have noticed the solar panels have moved.

This is due to a small incident where I realised after warping, that both panels were pointed away from the sun, and I had no electricty.

Fortunately, by the powers of KAS, Halzor was able to pull of one panel, and stick it on again where it would get light, saving the mission.

Having come all this way, without so much as a booster, Halzor ponders the future. What does this mean for space travel? What does it mean for physics? What does it mean for his Rockomax shares, if this is a practical way to put things into space?

After much contemplation, it was time to climb back aboard that frame of physics defiance, and head home.

(Also time for my navball and displays to glitch out apparently.)

Soon, I had accelerated to a Kerbin return trajectory. A nice, typical, low delta V requirement return.

But I have infinite delta V!

I pointed at Kerbin and just kept pushing, using a flag on top of the VAB as a target. I had to re-aim every so often.

Eventually, I got my return time down to two hours, leaving Minmus at about 5km/s. Then, there were some adjustments to do to make sure I had a periapsis within Kerbin's atmosphere.

There was one incident where I came loose from the frame, and had to use my dwindling RCS pack fuel to get back.

Using mechjeb to judge the aerobrake, it was a fine line between landing and staying on a hyperbolic trajectory. I probably could have adjusted with more precision when I was just outside the atmosphere, but that was risky. I decided to go ahead and land.

Have a look at the predicted G force!

The Periapsis was low enough to trigger parachutes. As I accidentally pressed stage earlier in the trip, the first attempt at landing ended in glitchy disaster as Halzor was ripped from his seat, plunged through the atmosphere hypersonic speeds, and made fatal contact with the ground somewhere I didn't see, due to camera glitches.

But, this was not hard to fix with tweakables.

This time, Halzor stayed in place when the parachute triggered.

I had hoped this "vessel" would be reusable. However, when the parachute fully deployed, a design flaw became apparent- the ship would be improperly oriented for launch after landing. Probably because the parachute was connected to the bottom node of the probe core. Oh well.

One graceful landing later...

And we've done it! One Kerbal sent to both moons, and returned, using no fuel at all!

Ladies and Gentlekerbs, you have just witnessed the future of space travel!

...Unless:

1. Some sort of life support is added. This ship can't lift any weight.

2. Reentry heating arrives.

3.Or, you know, they fix the glitch with ladders....

But, unless/untill these eventuate, the solar system's your oyster!

Probably not Eve. I don't think it's got the TWR.

Further testing fixed the parachute problem.

If you don't believe me, or want to try it out yourself, here it is:

https://www.dropbox.com/s/jdsu8xs6i3myovw/Laddership.craft

100% stock, and ready to go.

All the pictures of the mission can be found here:

Javascript is disabled. View full album

As for where I'll take it in the future...

This rendezvous was a battle and a half.

We'll see!

Edited April 24, 2014 by Tw1

[Accelerando]

Good God, you're brilliant. This needs to be tested over Jool's kill depth.

[Geschosskopf]

Congrats on this epic trip and the development of an infinite reactionless drive.

[Tw1]

I decided to break my usual rule of never hyperedit to another planet to test something, and had a go at an Eve ascent. I stripped the parachute and seat of to minimise weight, but I might have not needed to. It was very easy.

I documented it in this imgur album:

Javascript is disabled. View full album

Technically, I just claimed the record for lightest stock parts only Eve ascent...

Edited April 25, 2014 by Tw1

[Geschosskopf]

Well done! In yo face, gravity!

[NobodyIP]

Awesome! Only thing left to do now is a Grand Tour of all the planets.

[Tw1]

I decided to try the version with parachutes. Landing, I ran into a problem:

Something about Eve makes the frame want to land sideways. I couldn't get it to stay straight. Even when I tried jumping from safe height, so the balance would be improved.

I wondered if it had something to do with the fact that I recently changed to using RealChute. Testing on Kerbin showed this was not the case:

Looks like I won't be doing a "real" trip to Eve with this set up.

But, a little magic let me see if I would have been able to take off.

However, I soon found it would only slide across the ground.

Soon, it was rendered inoperable.

I tried a launch from flatter ground. Once again, the TWR wasn't enough. It was capable of bouncing, but not flight.

Looks like this guy will be here for a while, as we are reminded Eve is a harsh mistress.

Oh well. Eve wasn't an interplanetary target I had in mind anyway.

[tjsnh]

So, forgive my idiocy here.

How do you "fly" this?

It's on the ground .. you walk up to the ladder, and hit F to grab it ... then what? You can't use space suit RCS.

[Tw1]

So, forgive my idiocy here.

How do you "fly" this?

It's on the ground .. you walk up to the ladder, and hit F to grab it ... then what? You can't use space suit RCS.

You hold down "W" to make the Kerbal climb the ladder. Kerbal pushes ladder = small force.

[tjsnh]

Interesting .. I had no idea about this bug/feature ..

[Geschosskopf]

Interesting .. I had no idea about this bug/feature ..

The key is to give the Kerbal something at the end of the ladder to push against while climbing the ladder. If you put some obstruction on both ends of the ladder, you can move the vehicle both forwards and backwards (with backwards also acting like a brake). This works great for "pedal-powered" rovers and even boats. You can see some how to arrange the key parts such things here (although some of the pics have disappeared in the meantime):

http://forum.kerbalspaceprogram.com/threads/70225-Jeb-s-Bill-Powered-Rover

[Tw1]

Geschosskopf said:

If you put some obstruction on both ends of the ladder, you can move the vehicle both forwards and backwards (with backwards also acting like a brake).

I like to call the rear one the "jebcatcher" as in plane based experiments, I discovered the same trick after adding a part to stop Jeb falling off.

Anyway, today, the adventure continues. Meet Kelley Kerman.

 

 

 

She's been sitting in a tin can, high above the world, waiting for a launch window.

Behind her is Voyager. It is equipped with a few hundred m/s worth of monopropellant, for precision finalising of rendezvouses between the orbital module, and the Ladderlift lander.

Today, she left the Kerbin SOI. After a few a few smaller maneuvers:

I put this rock on my keyboard, as I watched TV:

And made a much bigger maneuver.

 

 

 

Where are we going?

Jool!

ETA, only 105 (Earth) days.

 

Edit: In the end, I made it to Jool, and got into a low, circular orbit. Then this mission was basically abandoned due to frequent crashes, which exacerbated the extreme tedium of babysitting the vessel for so long. 
I did, however, create an  Eve lander which was fully reusable: 

Contains some flashing. Epilepsy warning maybe? IDK.

This video was prompted by Andrew Hansen, a youtuber who was about to beat me to demonstrating a reusable lander. I managed to get this out first, but his mission is still definitely worth watching. He performed an interplanetary trip with Ladder power alone, and shows what can be done without a seat to warp with. It's an impressive achievement, seriously, watch it some time. 

This glitch is no longer as powerful as it once was, due to changes in how they handle physicsless parts, and the addition of reentry heating. 
But it's still a great trick, and similar can be done with just a walking kerbal for moving things on the ground.

Edited August 5, 2019 by Tw1

[RobotsAndSpaceships]

I am impressed.

[Tw1]

It is now 2019, and I am here to reclaim my crown as designer of the lightest Eve ascent vehicle Ever.  

Yep, that's right, this still works.
It's far more limited in the stuff you can lift, but it works. Reentry makes landing difficult now, but a ladder and some struts is still a very acceptable way to get yourself up there in the first place.  In some ways, it's easier with parachutes built into kerbals, and smarter SAS  for holding retrograde during powered landings. Plus, nodes persist through vessel changes, and you can climb a ladder while in map view now. 

Here I am taking a one way trip from Kerbin to the Mun with only ladder power

By lightly tapping, I could slow myself down for an easy landing, thanks to SAS holding retrograde for me.

After some refinement, I developed a variant which can sort of survive reentry, at least from LKO using both one drogue chute, and the kerbal parachute.

TBH, I'm not sure how much I trust it. It works, but is not as well as it used to. A powered deceleration and landing though, that is still entirely possible. 

But now, the main event: Eve. 

By stripping it down, I've built an Eve ascender that's only 124 kilograms. That's 218 if you include the kerbal. I stripped off the legs which give it stability, so launching it requires following an exact procedure:

0. Before you start, this should be done from a flattish location, with a good angle to the sun for power, and with a communications relay already in place. 

1. Climb up from the descent stage to the ascender, and get your kerbal right up under the probe core. 

 

2. Switch to the lander, activate SAS, and decouple the ascender.

3. Switch to the ascender, carefully adjust attitude so it is facing directly up

4. Switch to the kerbal, brace yourself and hold down W. 

It's about a 20 minute climb to the top of the atmosphere.

Once you have gained at apoapsis of about 200km ish, (or few minutes ahead of you, you can open map and keep climbing to check,) it should be plenty safe to switch to the ascender, rotate in the direction you want to go, and start pushing your way to orbit. Probably want to extend your antenna at this point to get probe control.

And that's that.  How to leave Eve the cheap way. 

This is a full mission from Kerbin, to Eve, and Back, with an earlier version of the ascender. 

Spoiler

Lift off on the EVE RETURN mission. Imaginatively named yeah, but KSC really wanted to stress the return part. 

Fairings drop away, revealing the cruise vessel. Our mothership, and comms relay for this mission. 

Our path to Eve, achieved using one perikerb kick. 

I call the current configuration of the vessel "firefly mode". Here, it's making a correction burn 

Aerocapture at Eve, the engines tucked in behind the shield. 

Three passes where used. TBH, the transfer was pretty good, I'm not sure I saved that much doing it this way.

On one, we lost a small tank to overheating. 

 

About one month in, 

The lander separates. Solid rocket boosters fire, the lander is spun up for stability. 

Dudvey Kerman is going to Eve.

The protective aeroshell was kept until we passed the clouds. Then, 

Parachute time!

The Lander was drifting down so nice and gently, so  Dudvey decided he'd go and look from a better spot:

and...

Touchdown! The site was near level, perfect for the return, and a hotspot of geological interest. It was perfect. 

Dudvey spent something like a year doing stuff on Eve.
One month before the return window, it was time to leave. He gathered up the science, stretched his gravity-strengthened muscles one more time, and climbed the ladder: 

Released the decoupler, 

Rock once again placed carefully on my keyboard....

Up we go!

This version if the ascender was more draggy and slow. By this point, he was still barely doing 12m/s.

Some 40 minutes latter:

A maneuver node was used to help align with the mothership. This helped overcome the complications the polar orbit added.

A joint effort between ascender and mothership, rendezvous was completed,  

And Dudvey ditched the ascender 

About a month later, it was time to leave.

Two PeriEve kicks and one inclination adjustment were performed before the final burn

Our plotted path back to Kerbin:

I call this configuration "The chandelure mushroom"

Arriving back at Kerbin, we performed an aerocapture, with one additional aerobraking maneuver. That second one was a little iffy. Things got a little heated.

But everything was fine, and one final burn put us in a stable parking orbit around Kerbin.

Mission successful. A run of the mill shuttle craft will pick up the astronauts, and return them home. 

I will also be adding a pack of craft files so anyone can check my work. They should be stock, though I might have left a mechjeb in there.
 

Edited August 5, 2019 by Tw1

[RealKerbal3x]

It’s amazing that this exploit hasn’t been patched out yet!

Now you’ve got me wondering if the Breaking Ground robotic parts have any extensions into the kraken’s realm that could be used to build a reactionless drive...