SRB Lander

[lucidLemon]

Are you as good as Jebediah? Prove it!

Your mission is to create a mun lander using only the raw power of SRB's.

Rules:

-You are allowed to use any means to send your lander to the mun.

-Once the lander is below 20,000m, the lander may only use SRB's; rocket engines and RCS are banned.

-You can edit and mod to your hearts content, but the SRB itself cannot be modified to be controllable after firing.

-Impact tolerance of any part can not exceed 50

-You must land mostly intact

-You must provide images of descent and touchdown

-Any achievements must have an image for evidence

-MET will be used to determine leader-board ranking

Achievements

-Honorary award: Keep the cockpit after a violent landing

-Mountain Goat: Land upright on a slope of 20 degrees or more

-Mountain Climber: Land on the peak of a mountain

-Explorer: The lander has a detachable rover (the rover can use non-SRB propulsion)

-There and back: The lander has a return stage capable of getting back home (the return stage can use non-SRB propulsion)

-Gentle Touch: Make contact with the ground at under 5 m/s

-Scout: Land by any of the Mun's mysterious structures

-Dedication: Use only stock parts

-Way of the Master: Use only SRB's

-Live Long: Complete the entire mission without having to reload

Leader board:

1. Banbite MET: 2:59:38 Achievements: Way of the Master

2. samiamthelaw MET: 6:06:54 Achievements:Dedication, There and Back

3. Nao MET: 7:16:16 Achievements: Dedication, Way of the Master

4. iplop MET: 8:45:34 Achievements: Dedication, There and Back (First!)

5. AmpsterMan MET: 9:53:54 Achievements:Dedication, Scout, There and Back

May Jebediah smile upon you.

Edited September 15, 2012 by lucidLemon

[TNTGODZZ]

you do understand that nomatter what you do, there is no way of landing on the moon with srb's?? you need atmosphere to burn the SOLID fuels.

[NovaSilisko]

No you don't. Not in KSP, not in real life. Solid rockets have oxidizer mixed in with the fuel, so they can burn in a hard vacuum as well as in the atmosphere.

[lickstaph]

This challenge isn't possible.

[pizzaoverhead]

It's far from impossible. You could probably do it with a single SRB. You just have to time it so that your altitude reaches ground level at the same time as your speed reaches 0 m/s, at the same time as the booster runs out. Simple! In theory.

Theory should be identical to practice, in theory...

[whatisthisidonteven]

This challenge isn't possible.

[Tim_Barrett]

I don't have time for the challenge, but why not put two SRB's on the sides of your pod that are connected via rotatrons?

Whenever you need to drop some altitude, just angle them so all of the energy is causing your ship to spin instead of going back into space.

Just a thought.

[lucidLemon]

I did quick test flight using the claw instead, it looks like it could work very well with proper timing.

I'll add an achievement for stock parts only.

PizzaovertheHead, mind if I put

Theory should be identical to practice, in theory...

in my signature?

Edited September 9, 2012 by lucidLemon

[Oggula]

Seeing as you need ~800dV for a munar descent and one SRB has ~3000dV, if you added and SRB to a 4.5 ton craft it should be pretty close

[Nao]

[light-bulb on] Just wanted to share an idea

You can actually stop SRB mid burn by extending landing gear towards it's exhaust (it shuts down 100% to 0%). It can be opened and closed until fuel runs out.

I'm not sure if I'll have time to do this but good luck to any challengers!

[Bluejayek]

That SRB double lander.. is amazing...

Edited September 10, 2012 by Bluejayek

[lickstaph]

You call that a landing? You and I obviously have very different ideas of what a landing is.

This challenge is impossible.

[sixpackabs]

i made a rocket that goes to the mun and back using all solids except one..... i used the one tiny liquid tank and engine for landing

[nhnifong]

It drives me nuts when people say things are impossible.

This can definitely be done, and if you really don't believe, then at least watch lurker's video linked above. He's quite impressive.

[whatisthisidonteven]

You call that a landing? You and I obviously have very different ideas of what a landing is.

This challenge is impossible.

It touched down on the surface of the bodies and came to a stop, that is a landing. Very clearly.

[cardgame]

You call that a landing? You and I obviously have very different ideas of what a landing is.

This challenge is impossible.

Someone already did a double - nay, a triple - landing - albeit a bit messy - so with some additional effort an exact landing is possible. Add an RCS tank and a couple of thrusters for precision, it's totally possible.

[Fendleton]

It's entirely possible to do this. It requires split-second timing and very good knowledge of your craft, as well as the elevation of the ground you're landing on. It'll never be easy, but it is 100% doable with enough skill and trial-and-error gameplay.

[iplop]

All this talk of impossible annoyed me so I went ahead and landed a pure SRB lander. ;D

Completely stock, no CFG edits:

Arch is in the lower left portion of this photo:

It landed completely intact but on its side(this took many quick-loads to accomplish).

Now I need to decide if I'll try again from my save, end the mission for the stats, or try to continue onward. :/

Edit:

Apparently I'm near the arch. :>

Edit_2:

To save and try more drastic measures for righting my craft or to try again...

Edit_3:

Got it!!!

Without having to try for another landing!

-will work on getting it back to kerbin tomorrow (will 4 SRBs be enough? O.o)

Here's the file if anyone wants it: [ATTACH]32760[/ATTACH] (it's just a really old design of mine with an SRB lander slapped on top)

Edit_4:

Here's the strategy I used:

1) Rounded off Munar orbit at ~100k m altitude

2) When over where I wanted to land I performed a retrograde burn until I was falling straight down

3) Ejected the liquid stage when my transition to a straight fall was complete (~70-80k m altitude)

4) As you can tell by one of my pics, I originally intended to use the 4 outside SRBs to decelerate. This didn't work out (too powerful) so I ended up switching them around mid-fall

5) I brute forced the exact altitude to engage the landing SRB (turned out to be roughly 7,150m altitude)

Edited September 10, 2012 by iplop

[Ziff]

You call that a landing? You and I obviously have very different ideas of what a landing is.

This challenge is impossible.

You keep using that word. I do not think it means what you think it means. It is clearly possible to land using SRB's, this challenge is not impossible. It is difficult, yes. It requires some thinking outside the box, and a bit of luck. Still, it's totally doable.

[papagoose]

It's entirely possible to do this. It requires split-second timing and very good knowledge of your craft, as well as the elevation of the ground you're landing on. It'll never be easy, but it is 100% doable with enough skill and trial-and-error gameplay.

I would guess one strategy to follow would be

- Orbit Mun at some calculated altitude

- Use liquid rockets to reduce orbital velocity to 0, and hover

- Hover as precisely as possible at this calculated altitude

- Cut off liquid engines and drop down

- Ignite SRB at precisely computed height

- Make sure the pod is controllable enough to remain perfectly upright

- Win.

I don't know offhand how difficult it will be to compute the height...well, for x being the altitude, we have something like

d^2x/dt^2 = -m(t)F_g(x) + m(t)F_r(t)

where F_g is the gravitational force which depends on altitude, F_r is the SRB thrust and the dependence on time comes from the time of ignition (it is a step function that is zero at all times except when it is the constant thrust produced by the SRB when it is burning), the target condition is x=0,dx/dt = 0 and F_r(t) = 0 at x = 0, so then integrate backwards for the duration of time the SRB burns for, and this will give the required vertical velocity at the altitude when the SRB should be lit. Then, work out how long a freefall (from orbital hovering) is required to arrive at this altitude with the correct velocity. It would make sense to do something like aim for a landing velocity of dx/dt = -5m/s or something so that there is a bit of leeway, as long as the lander was designed to sustain a -10m/s impact or something.

[lickstaph]

Edit_3:

Got it!!!

Without having to try for another landing!

Congratulations. You are, most definitely, the first to ever accomplish this. Ever. Full stop.

You keep using that word. I do not think it means what you think it means.

Go back to /b/.

[whatisthisidonteven]

Congratulations. You are, most definitely, the first to ever accomplish this. Ever. Full stop.

Go back to /b/.

There was a video a few pages back that showed someone doing it before that.

[iplop]

Congratulations. You are, most definitely, the first to ever accomplish this. Ever. Full stop.

Go back to /b/.

Thanks!

Unfortunately it's definitely been done before (I'm pretty bad at detecting sarcasm online -not sure if that was genuine or not).

The video "whatisthisidonteven" posted includes lots of nifty tricks. Such as: helicoptering down with canards instead of using a parachute. :>

He also uses a method for wasting thrust that I wasn't able to copy. I read elsewhere that it's the same method glider pilots (real life) use to hold position when their visibility is poor.

Edited September 10, 2012 by iplop

[Punk]

Method for wasting thrust? You mean the out of control spinning end over end? Now that would be something to try in a glider...o

[TinfoilChef]

I'd have said this in a youtube comment but you've got comments and ratings disabled. That has got to be the wildest, craziest, most amazing set of landings I've ever seen!

And in response to somebody saying "You call that a landing?" all I can say is "any landing you can walk (or fly!) away from is a a good one."