RSS/RO Heavy payload Mars Landing

[Mr. Sandman]

So..I'm trying to start a colony on Mars in RSS/RO and I'm pretty much stuck.I landed on the Moon and landed some rovers on Mars , no problem.Now I have to land heavier payload on Mars , but it seems I'm not able to do so.

This is what I should land.I already tried everything , from parachutes to big heatshields (I don't have small and powerful retro rockets, sadly).So yeah , that's the problem.Thanks for everyone that gives me a tip.

[GehringGame]

I admire your ambition! So is the problem that your parachutes can't slow you down enough for a soft landing? Why not just bring more or larger rocket engines to enable a powered landing? Does that add too much to payload mass?

[Mr. Sandman]

3 minutes ago, GehringGame said:

I admire your ambition! So is the problem that your parachutes can't slow you down enough for a soft landing? Why not just bring more or larger rocket engines to enable a powered landing? Does that add too much to payload mass?

The parachutes slows down , but I have no small retro rockets for soft landing (we all now how Mars is on landings with parachutes only).So yeah , the main question is : 1) Engines for powered landings?(restartable , possibly) 2) TWR needed to have a slow and steady landing?

Oh and thanks for your help

Edited June 22, 2017 by Mr. Sandman

[GehringGame]

Without knowing what mods you have installed and where you are in the tech tree progression, it's hard to recommend a specific engine to use for landing. Maybe others can offer suggestions based on their experience. I would recommend a TWR of around 2.0 (relative to Mars gravity) in order to make a nice, controlled landing. Anything above 1.5 would be fine, but below that it get's tough.

[regex]

Also, the delta-V of that craft? What's the Mars stats for it? Were I to build something like that (not saying I have) I would probably try an aerocapture followed by parachutes for braking with a propulsive landing. If my Earth LV could loft enough and my transfer stage had enough delta-V I'd probably skip aerocapture and move straight on to parachute braking with propulsive landing.

E: This subway map says you need 3800 delta-V for a propulsive landing on Mars. You can probably cut that by using parachutes for some braking but the atmosphere is pretty thin.

Edited June 22, 2017 by regex

[Mr. Sandman]

28 minutes ago, GehringGame said:

Without knowing what mods you have installed and where you are in the tech tree progression, it's hard to recommend a specific engine to use for landing. Maybe others can offer suggestions based on their experience. I would recommend a TWR of around 2.0 (relative to Mars gravity) in order to make a nice, controlled landing. Anything above 1.5 would be fine, but below that it get's tough.

Thanks for the TWR tip and don't worry about the progression(It's a sandbox game!).

About my mods , this is my Gamedata Folder :

If you have some mods on landing engines to suggest (or mods to remove if you think they are just a waste of precious RAM) tell me.

17 minutes ago, regex said:

Also, the delta-V of that craft? What's the Mars stats for it? Were I to build something like that (not saying I have) I would probably try an aerocapture followed by parachutes for braking with a propulsive landing. If my Earth LV could loft enough and my transfer stage had enough delta-V I'd probably skip aerocapture and move straight on to parachute braking with propulsive landing.

E: This subway map says you need 3800 delta-V for a propulsive landing on Mars. You can probably cut that by using parachutes for some braking but the atmosphere is pretty thin.

Oh I know that , but here the main problem is a lack of small (and powerful enough) retro rockets that I can fit on the craft.About the ΔV (on Mars for retro fire) is about 200-300.I can't give you the ΔV for the rocket , since I still have to build one big and powerful enough for heavy payload to Mars.

Edited June 22, 2017 by Mr. Sandman

[Mr. Sandman]

Ok so I tried some stuff and I got this

It's an exoskeleton with 4 engines (pretty high TWR though) , restartable (infinite ignitions) and with 930 m/s  ΔV.Still , the engines are pretty big.

[regex]

29 minutes ago, Mr. Sandman said:

Oh I know that , but here the main problem is a lack of small (and powerful enough) retro rockets that I can fit on the craft.About the ΔV (on Mars for retro fire) is about 200-300.

Have you tried procedural SRBs?I think a battery of LMDEs is probably your best bet, there aren't many historical landing engines for heavier payloads besides that. Upper stage hypergolic engines like the AJ-10 are another good place to look, I would think.

[Mr. Sandman]

4 minutes ago, regex said:

Have you tried procedural SRBs?I think a battery of LMDEs is probably your best bet, there aren't many historical landing engines for heavier payloads besides that. Upper stage hypergolic engines like the AJ-10 are another good place to look, I would think.

Looks like a cool idea I can use in future and heavier landings.This is just a test craft ti see if I can produce fuel with RealISRU on Mars , then the full scale colonisation will start.Thanks for your time and tips!

[GehringGame]

2 hours ago, Mr. Sandman said:

Ok so I tried some stuff and I got this

It's an exoskeleton with 4 engines (pretty high TWR though) , restartable (infinite ignitions) and with 930 m/s  ΔV.Still , the engines are pretty big.

I think that looks pretty good, really. If you don't like the look of the engines hanging around after landing, you could mount them on a disposable frame that can detach and go crash somewhere after landing. Best of luck with the flight!

[Mr. Sandman]

Just now, GehringGame said:

I think that looks pretty good, really. If you don't like the look of the engines hanging around after landing, you could mount them on a disposable frame that can detach and go crash somewhere after landing. Best of luck with the flight!

Trying to do so.The landing is flawless in the test I ran (some explosions during faring and heatshield separation , but fixable)Thanks a lot!

[Human Person]

On 22.6.2017 at 4:43 PM, Mr. Sandman said:

1) Engines for powered landings?(restartable , possibly) 2) TWR needed to have a slow and steady landing?

1) Yes, and yes, having restartable ones here is very important.

2) You only assist your chutes, so you can go with a  TWR < 1. If you go for higher TWR, make sure your engines have decent throttle capabilities. 

[Mr. Sandman]

5 minutes ago, Physics Student said:

1) Yes, and yes, having restartable ones here is very important.

2) You only assist your chutes, so you can go with a  TWR < 1. If you go for higher TWR, make sure your engines have decent throttle capabilities. 

I'm using the Astris engine at the moment.It's powerful , restartable but not throttleable.About the TWR you look to be right , I've only to slow down from 30 m/s to 5-6 m/s for a good landing with a refinery.Thanks for the tips.