The planetary lander delivery challenge

[liorg1993]

As you all know, version 0.17 will be bringing us new planets to explore.

So I have decided to start building a ship that will take me to the red desert planet(Mars) as a start.

I have managed to build a relatively stable lander, capable of landing(as of now on Kerbin) using parachutes and later taking off and reaching orbit with enough fuel to make an interplanetary flight back home.

<i>But here's my problem:</i> the lander is <b>VERY</b> heavy (40 tons!), and i'm not able to build a rocket stable enough to send it to mars.

So i'm proposing a challenge:

Build a rocket capable of launching the lander into low kerbin orbit(LKO) and having enough fuel to send it to mars and bring it for a landing trajectory(900-1000 d/v <b><i>should</i></b> be enough).

<b><u>Rules:</u></b>

a) The rocket should be stable and not break at any point during the flight.

The rocket should be small enough to not make an astronomic lag during takeoff. I have a very powerful PC and I'm still getting some serious lag when it comes to huge ships

c) Using <b>only</b> stock parts.

<u>The lander:</u> <a href="https://www.dropbox.com/s/y2lh4vx6z5kbkrv/Heavy%20Lander.craft">Download Here</a>

<u>Pics:</u>

<b>Good Luck!</b>

Edited August 26, 2012 by liorg1993

[r_rolo1]

12 (!!!!) aerospikes + 1 LV in a lander ? + 12 big parachutes and a small one ? You really like to play it safe ...

Well, before entering any idea on how to make a launcher for this, you might want to review your fuel lines and staging in the launcher. You can definitely do it in a more efficient fashion.

On the launcher, as I can't launch the game now, I can't mount it but I have some ideas that revolve around using all of those engines you already have ( 12 aerospikes can deliver roughly the same punch than 3 of those big engines ) to assist in the launch...

[Bluejayek]

I would do this except that you are comitting the sacrilege of using mechjeb, so I can't load the file.

[liorg1993]

12 (!!!!) aerospikes + 1 LV in a lander ? + 12 big parachutes and a small one ? You really like to play it safe ...

Since only the middle section of the lander is left after launching from Mars, i'm going to be using the small parachute to land the command pod after the rest of the ship is jettisoned.

The 8 larger parachutes are the only way I could slow this beast down and keep it from crashing into the ground.

Also, the aerospikes are the most powerful and economic engines in the game and help me keep my lander lighter and easier to land and launch back home.

[liorg1993]

I would do this except that you are comitting the sacrilege of using mechjeb, so I can't load the file.

Sorry, I was using Mechjeb to see the weight of the lander.

I'll re-upload it with only stock parts.

[r_rolo1]

As I'm a nice guy, I'm going to post the lander without mechjeb ( I want to see more good ideas ). See here

[erkle64]

12 (!!!!) aerospikes + 1 LV in a lander ? + 12 big parachutes and a small one ? You really like to play it safe ...

4 of those parachutes are actually nose cones, which actually seem to add drag.

[cardgame]

The heavy aerospikes can probably be dropped for some lighter engines, since efficiency matters a bit less as part of the payload stage...

[liorg1993]

The heavy aerospikes can probably be dropped for some lighter engines, since efficiency matters a bit less as part of the payload stage...

Could you please clarify as to how the aerospikes are heavier than the other engines? Isn't it the other way round?

And what do you mean by "payload stage"?

[r_rolo1]

4 of those parachutes are actually nose cones, which actually seem to add drag.

Even then it is most likely too much ( I assume this is a Mars analogue lander, right ? ) I have serious doubts about the ability of those tanks that have the chutes to stay attached to the ship as it is now ... IMHO the ship needs far more struting. Oh and how about replacing those fixed stairs by adding another extendible ladder ( check the weights ) ?

BTW, and for my own convenience for my delivery rocket, I worked up the lander staging and fuel lines a little... The ship lost in stability ( due to the small strutting force of the fuel lines, my non radially symmetric fuel line placement tends to make the ship spin ), but it gained in efficiency ( in my tests it made to a Kerbin 70*70 km orbit with 30% more fuel than your lander while using the same flight plan ). If you want to use it get it here ...

@cardgame

Other alternative is to use those engines in the launch ( thus, they are not simply payload ). That is what I intend to do.

[liorg1993]

Thanks for the idea of rearranging the fuel lines! It really helps during the lander's ascent stage.

However, I'm having problems using the aerospikes during liftoff from Kerbin because the lander's fuel tanks are being depleted no matter how I connect the fuel lines to the main rocket

[simplemunrockets]

I never knew we had that smiley...

Anyway, you have to put the first end of the fuel line on the tank that's supposed to drain.

[r_rolo1]

I'm facing the same difficulties ... the game really does not like complex fuel line systems, especially ones that go from the center and come back. This will need some extra engineering...

[Werwolf]

failing horribly at the challenge, but loving the lander, thanks

[SLAMS]

One problem, the desert planet atmosphere is supposed to be too thin for a parachute only landing. You might be able to radial parachute spam but that's kinda cheating(I'm doing it if I can't find a way around that).

Maybe have stages of parachutes and a shallow entry angle?

I have a lander slightly smaller than this (i think) that can land with no chutes, but it can barely hit orbit. Also I built it before I knew about the fuel bug so I don't know if it will work.

[PigletPG]

i made one that is far lighter than the one in the OP. How do I post craft-file and a picture of it? Do I need to upload it externally or can I do so internally? If external, where? if internal, how?

[liorg1993]

One problem, the desert planet atmosphere is supposed to be too thin for a parachute only landing.

I am aware of this problem.

Fortunately the desert planet's gravity should be smaller than Kerbin's and my tests show that even if the parachutes don't slow the lander enough, you can always add a tiny bit of thrust at the very end of the landing to compensate and barely lose any fuel.

Edited August 27, 2012 by liorg1993

[liorg1993]

How do I post craft-file and a picture of it? Do I need to upload it externally or can I do so internally? If external, where? if internal, how?

I've never tried uploading files internally(not even sure if that's possible) but you can easily upload using sites like Dropbox or Mediafire.

[Apotheosist]

I am a keen interplanetary spacecraft builder. When I start, I make sure I have the lightest, most efficient possible lander to begin with, because I know the rocket needed to lift it into space is going to be huge. I don't think there is need for so many engines, decouplers and parachutes. My landers usually use 2 parachutes, and I use the engies to help slow the craft down the last few m/s. My landers also tend to include enough fuel to circularize the parking orbit as well as conduct the interplanetary injection burn, this means you only need to put the lander in LKO and it can do the rest. This helps because when you're in low kerbin orbit, lining up for your interplanetary burn, you don't want to have to maneuver a large booster stage. It also avoids creating space junk. It also means that when you arrive at your destination planet, most of the spaceship is empty tanks, which make for useful low density parachute attachement points.

Personally I think it would be a good idea to redesign the lander. It has far more thrust than it needs, yet it is very complicated and difficult to rig fuel lines to use the extra thrust from those engines to power the booster stage.

Anyway you asked for a rocket to get this lander into space, so I have attached a craft file with your lander and a booster that gets it into orbit with plenty of delta-v to spare. It is a very simple booster. It may take some time to orient the rocket in space without using the thrust vectored engine. The flight plan I used was also very simple; full throttle, pitchover 45 degrees at 12km, then 90 degrees at 30km or less, then circularize at desired parking orbit.

Edit: Not sure if it's letting me attach the craft file. Working on it.

Edit 2: Mybe this will work: http://www./?e7jdwcvbd7epgt7

Edited August 27, 2012 by Apotheosist

[SLAMS]

Anyway you asked for a rocket to get this lander into space

IMO that's the easy part(not really), once in orbit it would need enough fuel to make a planetary SOI change. I've seen several people make rockets that could reach LKO, land, reach LKO again, then land on chutes (I made one a while back). But I haven't seen one powerful enough to go to another planet.

Everything I tried ended up making the craft simply too heavy and too big. For instance my attempt had 12 of the biggest solid boosters 6 one meter liquid 'boosters' and 6 three meter liquid main engines... in the first stage. Though I didn't use any throttle until I ditched the boosters.

Now that I have more experience I'd say best bet is to do the entire lift stage with large solid boosters and finesse.

[Apotheosist]

I've seen several people make rockets that could reach LKO, land, reach LKO again, then land on chutes (I made one a while back). But I haven't seen one powerful enough to go to another planet.

I have already made one powerful enough to go to another planet. Without making use of the fuel bug. And it is not very big. Four large 3m engines and 4 large SRB's on the first stage. Then 3 aerospikes, 2 small srbs, and last stage 1 smallest engine. I designed it as a minimal rocket, using my minimalist design techniques and philosophy.

It can go to the Mun and back twice. This gives enough delta-v to get to another planet.

[liorg1993]

@Apotheosist

I think your design is very good although lacking in stability.

In my tests the ship kept falling apart during takeoff, but I fixed this by adding more struts to the big liquid fuel tanks.

The design does look promising and I'm certainly going to try it out once the next version comes out.

I think the challenge will only be over once 0.17 is released and we are able to test all of the designs properly.

Until then, keep sending them in!

[Apotheosist]

It did shake about a bit with me, I realised a few extra struts would fix it, but I didn't bother because although the tanks moved a bit it never actually broke apart with me.

0.17 might bring it's own changes and re-balancing to the parts, meaning we might have to build our rockets again. We will have to wait and see

[Apotheosist]

Just in case you find it interesting, here are pictures of my interplanetary spaceship, which can go to the Mun twice.

http://imgur.com/a/a0MHt

[SLAMS]

Just in case you find it interesting, here are pictures of my interplanetary spaceship, which can go to the Mun twice.

http://imgur.com/a/a0MHt

I have the sneaking suspicion Aerospikes are going to get nerfed, they are just too powerful/efficient.

Also Nova stated that chutes would only slow you to 200-300 meters per second on the desert planet. Which is faster than a dead fall at lower altitudes on Kerbin, so a better test would be a hard landing(no chutes), then add chutes for the actual mission to compensate for the lack of air resistance.