Prove Elon Wrong: Mission to Mars (on the cheap)

[sevenperforce]

One of the things Elon Musk said in his September 2016 speech about the ITS was that the cost of getting to Mars is essentially infinite right now. In his powerpoint, he put it at $10 billion per person. Now, the logistics of the ITS aside, I wonder how accurate this is. How much WOULD it cost to get humans on Mars? What are the different cost breakdowns of different approaches, and which mission configuration would be best? And, most importantly, what happens if we Kerbal it?

The challenge is to send a few Kerbals to Duna, using only currently-available propulsion methods, with enough supplies to live on for the trip, as cheaply as possible. Rules:

1. Propulsion. No nukes and no airbreathers. SABRE isn't up and running, and NTR isn't likely any time soon, so your propulsion needs to be chemical only. No ion engines; we need to assume you're running against some kind of a deadline.
2. ISRU. Nope, sorry. We can't wait around on Duna forever.
3. Payload. Send up to 12 Kerbals to the surface of Duna and bring them back to Kerbin. But they need consumables, right? Let's be very Spartan and say that they each need a total of 0.2 tonnes of food and other consumables for each leg of the trip. You can pack that extra payload any way you want; that's approximately two Science Jrs per Kerbal, and you can ditch up to half of them (they're empty, after all) before you enter Duna's SOI.
4. Prop transfer. This is not only permitted, but encouraged. I highly recommend it.
5. Reuse. Recovery of components is encouraged by a cost reduction as outlined below.
6. Scoring. Your total score is the total mission cost divided by the number of Kerbals you actually land on Duna and return safely. Kerbals which stay in Duna orbit do not count, and dead Kerbals do not count. Any recovered components (reusable launch vehicles, etc.) are counted at 30% of their full cost. You do not have to include the cost of whatever you use for dry mass payload for consumables. The winner is whoever has the lowest score.
7. Mods. No part mods and nothing that would affect scoring, but anything else is fine.

I only have the Demo, or I'd make my attempt, but obviously this can be done. I'm mostly interested in seeing HOW it is done, what mission architectures are used, and so forth.

Good luck!

Edited May 4, 2017 by sevenperforce

[Numerlor]

You should add some dead weight for shielding if we're talking realistic

Edited May 4, 2017 by Numerlor

[Rath]

4 hours ago, Numerlor said:

You should add some dead weight for shielding if we're talking realistic

One short I-beam maybe?

[EpicSpaceTroll139]

Errm... Going to Duna in the Kerbal universe is hardly comparable to going to Mars in real life. The ∆v required to get to Duna is roughly comparable to what it takes to get to Low Earth Orbit. Duna's atmosphere is way more helpful at slowing your craft down and doesn't cause significant heating like entry into the Martian atmosphere. In KSP there is no possibility of solar flares or ionizing radiation in general. There is no life support in stock KSP. Nor is there cryogenic propellant boiloff. Parts are also 100% reliable.

The only way to make this even somewhat comparable would be to require the use of Realism Overhaul. Even then, I'm not sure that part prices are comparable. (What exactly is a  in $?)

Sorry if I sound like I'm trying to tear your challenge apart, but I just wanted to point out that stuff is way harder in real life.

Edited May 5, 2017 by EpicSpaceTroll139

[sevenperforce]

1 hour ago, EpicSpaceTroll139 said:

Errm... Going to Duna in the Kerbal universe is hardly comparable to going to Mars in real life. The ∆v required to get to Duna is roughly comparable to what it takes to get to Low Earth Orbit. Duna's atmosphere is way more helpful at slowing your craft down and doesn't cause significant heating like entry into the Martian atmosphere. In KSP there is no possibility of solar flares or ionizing radiation in general. There is no life support in stock KSP. Nor is there cryogenic propellant boiloff. Parts are also 100% reliable.

The only way to make this even somewhat comparable would be to require the use of Realism Overhaul. Even then, I'm not sure that part prices are comparable. (What exactly is a  in $?)

Sorry if I sound like I'm trying to tear your challenge apart, but I just wanted to point out that stuff is way harder in real life.

You're absolutely right, on all of your points.

I'm not actually trying to solve for the minimum cost of getting to Mars; obviously it is easier to get to Duna in KSP than it is to get to Mars IRL. Of course, the engine TWRs and fuel tank fractions in KSP are a lot more punishing, but not enough to make up for it. But this challenge is more about finding a mission configuration and architecture that will permit the lowest overall cost, once things like consumables are factored in.

Hope that makes sense.

[MarvinKitFox]

5 hours ago, Rath said:

One short I-beam maybe?

300 or 400 should do.

 

Also, remember to run your trip from Earth to Mars, not from Kerbin to Duna.

Realism overhaul, including Real Solar System is a must.

 

Remember to include TAC life support or something similar.

 

No nukes allowed. No Ion drive allowed, unless you nerf them down to realistic thrust (about 1/1000000 of current game levels)

 

[CairoJack]

4 minutes ago, MarvinKitFox said:

Remember to include TAC life support or something similar

I think kerbalism is better

[sevenperforce]

10 hours ago, MarvinKitFox said:

300 or 400 should do.

Also, remember to run your trip from Earth to Mars, not from Kerbin to Duna.

Realism overhaul, including Real Solar System is a must.

Remember to include TAC life support or something similar.

No nukes allowed. No Ion drive allowed, unless you nerf them down to realistic thrust (about 1/1000000 of current game levels)

If desired, we can do two leaderboards: one with RSS and one without. But this is more about mission configuration than getting everything perfect.

[Cunjo Carl]

@sevenperforce Your opinion on the inflatable heat shield, and space planes?

Edit: I'm assuming to go without them, but if they fit by your thoughts for the challenge, they'd probably wind up being very useful.

Edit edit: Oh duh! Also, what's your opinion on external command seats and cramming Kerbals into service bays? Again, I'm defaulting to no, but figured I should ask.

Edit edit edit: I built a rocket. So far so good! I'm going to try modifying the SRB clusters to be recoverable from here. The Duna to Kerbin leg of the mission is all set, so now just setting it up for the trip there . I'm trying out a new design aesthetic for this one, and while it's not a very realistic rocket, the Kerbal in me is getting a kick out of it.

.

Edited May 6, 2017 by Cunjo Carl

[sevenperforce]

10 hours ago, Cunjo Carl said:

@sevenperforce Your opinion on the inflatable heat shield, and space planes?

Edit: I'm assuming to go without them, but if they fit by your thoughts for the challenge, they'd probably wind up being very useful.

Edit edit: Oh duh! Also, what's your opinion on external command seats and cramming Kerbals into service bays? Again, I'm defaulting to no, but figured I should ask.

Edit edit edit: I built a rocket. So far so good! I'm going to try modifying the SRB clusters to be recoverable from here. The Duna to Kerbin leg of the mission is all set, so now just setting it up for the trip there . I'm trying out a new design aesthetic for this one, and while it's not a very realistic rocket, the Kerbal in me is getting a kick out of it.

.

Get the Kerbals there any way you want, but remember that you need to pack enough dry mass (in whatever form you'd like) for each leg of the trip, as I outlined above.

Spaceplanes and inflatable heat shields are perfectly fine! But you can't land horizontally on Duna; that's a bit too unrealistic. So even if you use a spaceplane, it would need to land vertically, somehow. And you can't reuse inflatable heat shields, so that cuts into your score a bit.

On reuse -- you don't have to actually reuse everything; you just need to demonstrate reuse. For example, if someone went the ITS route with a RTLS booster launching a persistent second stage, you'd only need to perform the RTLS once, though you'd need to reserve the same amount of propellant on all subsequent launches. That should save you some time.

[Cunjo Carl]

@sevenperforce Thanks! I've got the dry mass for the trip home in the form of extra crew storage. There's room for 17 Kerbals, but we're bringing 12 (maybe 13 so there can be a cameraman in deference to Mars One ) Anyways, one of those hitchiker storage containers is the drymass coming back. As I continue working, I'll find somewhere to put another one for the trip there. Those hitchiker storage units are the spitting image of the hab module in the old mars direct proposal, so I feel obligated to use them over the more convenient options! If it's permitted, the most cost optimal way of transporting Kerbals is by cramming them into chairs in service bays. It's lighter, cheaper, and much more resiliant during reentry. There's really never a reason to do otherwise, except it gets a little old, so I'll stick with my hitchiker cans for now. Still with that trick this mission could be made 1/4 the size (and cost)!

Example from an old challenge

Thanks for requiring demonstration of reuuse, not reuuse every time! It makes a big difference.

[sevenperforce]

33 minutes ago, Cunjo Carl said:

@sevenperforce Thanks! I've got the dry mass for the trip home in the form of extra crew storage. There's room for 17 Kerbals, but we're bringing 12 (maybe 13 so there can be a cameraman in deference to Mars One ) Anyways, one of those hitchiker storage containers is the drymass coming back. As I continue working, I'll find somewhere to put another one for the trip there. Those hitchiker storage units are the spitting image of the hab module in the old mars direct proposal, so I feel obligated to use them over the more convenient options! If it's permitted, the most cost optimal way of transporting Kerbals is by cramming them into chairs in service bays. It's lighter, cheaper, and much more resiliant during reentry. There's really never a reason to do otherwise, except it gets a little old, so I'll stick with my hitchiker cans for now. Still with that trick this mission could be made 1/4 the size (and cost)!

Example from an old challenge

Thanks for requiring demonstration of reuuse, not reuuse every time! It makes a big difference.

I'm not sure if I am understanding you correctly or not, but one thing to note is that the dry mass must be excess; you can't say that a manned crew cabin or an occupied storage container is "dry mass". Now, if you are bringing an empty cabin or an empty storage container to represent your dry mass, that works just fine.

A very good approach for getting your consumables there would be to add parts with liquid fuel storage. Liquid fuel can't be used by rocket engines, so it is a nice compact way to get that dry mass.

If I was being a little more realistic I'd specify the need for some large-volume module to act as a transfer hab for astronaut space, but that would get messy.

Once you've demonstrated reuse, you can carry the fuel you would need with crossfeed disabled.