Author Topic: A Dragon derived general purpose Mars lander?  (Read 55554 times)

Offline douglas100

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Re: A Dragon derived general purpose Mars lander?
« Reply #60 on: 04/23/2012 08:56 pm »
They tested the merlin vacuum by sticking it on a rocket.  Using your examples (Beagle 2 or MPL), if they made a few of them at the same time instead of just 1, then subsequently launched versions would have been better and cheaper.  It isn't like SpaceX plan to only ever land 1 thing on Mars.  Doing the mission faster better and cheaper could be a good way of gathering data for  follow-on red dragons (improving the success). Conversely, if you don't aim to be faster & better & cheaper, you likely won't be. 

As they said at the time of cheaper, better, faster, "choose any two." After MPL NASA abandoned the approach.

The Soviet Union tried something like this approach. In 1971 they launched two orbiter/landers and had a partial success with the Mars 3 lander. So they tried again 1973. This time they launched four Protons during the launch window and did less well than in  71.

 You talk about Mars landers as if they were something coming off the production line and "we'll just keep launching them (along with an FH each time) until we get it right." This is completely unrealistic. That is how you make yourself bankrupt if you're a private company.
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Offline douglas100

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Re: A Dragon derived general purpose Mars lander?
« Reply #61 on: 04/23/2012 09:02 pm »
I think they will, because like you, I believe Elon is sincere in his Mars ambitions.
If he can't do it a lot cheaper those ambitions won't amount to much.
So it seems that for the first time there is someone with the 'possible' means and the sincere desire too get to Mars, IF they can to it cheaply enough.

It all depends on the fate of SpaceX and how well they execute their customer contracts so that they remain in business. But then I think Musk will need substantial outside investments to realize his Martian ambitions.
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Offline go4mars

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Re: A Dragon derived general purpose Mars lander?
« Reply #62 on: 04/23/2012 09:42 pm »
You talk about Mars landers as if they were something coming off the production line and "we'll just keep launching them (along with an FH each time) until we get it right." This is completely unrealistic. That is how you make yourself bankrupt if you're a private company.
There's a dragon assembly line.  That's a big difference.

If the first Red Dragon mission costs $500 million, including the science instruments, and including launch, I think it's fair to assume that the cost of dragon including Mars related changes and developments are less than $300 million (Assuming $200 million for science payloads and a FH launch). 

If a "crew dragon" not including launch vehicle costs in the range of $90 million, then we are at a maximum "red dragon" cost difference of $210 million (which includes development costs of re-purposing dragon). 

If we assume that $60 million of that is in new dragon hardware (interplanetary communications, programming, control systems, etc.), and $150 million of that is for the development of that hardware and new features, then it leaves us with we end up with a cost of $350 million for all subsequent dragon missions (assuming the science payloads and launch costs don't get cheaper). 

The data from the first one should lend tighter margins to subsequent missions (more downmass on the next ones).

In a budget constrained environment, paying $250M to have a company take your tonne+ on a ride to the surface of Mars sounds like a pretty good deal to me.  If folks are worried about getting rovers out of the hatch, a "saws-all" on a track inside the pressure-hull would be worth looking at. 


I don't understand the skepticism in your statement above.  Dragons and FH cores are something that is coming off the production line. 

To be fair, falcon cores won't be into "production mode" for another 6 months or so.  But the dragon line is pretty much ready to go. 
« Last Edit: 04/24/2012 01:48 am by go4mars »
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Offline douglas100

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Re: A Dragon derived general purpose Mars lander?
« Reply #63 on: 04/23/2012 10:51 pm »
There isn't a production line for Mars landers. The Dragons being produced are for COTS.

There is no current market for a production line of Mars landers.

Quote
I don't understand the skepticism in your statement above.

That's because you keep making unrealistic proposals.
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Offline oiorionsbelt

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Re: A Dragon derived general purpose Mars lander?
« Reply #64 on: 04/23/2012 11:44 pm »
There isn't a production line for Mars landers. The Dragons being produced are for COTS.

Is the COTS Dragon  production line easily modified  for Dragon Rider/ Red Dragon?

Offline go4mars

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Re: A Dragon derived general purpose Mars lander?
« Reply #65 on: 04/24/2012 01:50 am »
Is the COTS Dragon  production line easily modified  for Dragon Rider/ Red Dragon?
The cost estimate and statements made with the proposal suggest that the production line is easily modified for red dragon (a few bells and whistles added to a stock dragon). 
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Offline beancounter

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Re: A Dragon derived general purpose Mars lander?
« Reply #66 on: 04/24/2012 03:25 am »
Is the COTS Dragon  production line easily modified  for Dragon Rider/ Red Dragon?
The cost estimate and statements made with the proposal suggest that the production line is easily modified for red dragon (a few bells and whistles added to a stock dragon). 

Well there's certainly going to be a few second-hand Dragons floating around.  Various configurations could be tried on some of these which should be possible and they've been paid for.
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Offline charliem

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Re: A Dragon derived general purpose Mars lander?
« Reply #67 on: 04/25/2012 03:03 am »
... I think that comparing the development of a launch vehicle with the development of a spacecraft might not be too useful. Spacecraft (I mean main payloads) are often more expensive than their launch vehicles. ...

I think it makes more sense to compare like with like. We should compare a hypothetical SpaceX Mars lander with real Mars landers past and present when we debate whether SpaceX can do a Mars lander radically cheaper.

And in return, my question to you is, do you think they can do a Mars lander a lot cheaper than in the past and if so, why?

Ok, lets then talk development and building separately.

About development: 6 successful landings on Mars to date, one more in the coming. 5 different designs, although all of them variations of the same basic idea (including MSL). That meant savings in development for the last 4, but also that not being identical they had to expend some more (from the news I read quite more).

The case for SpaceX is not that different. They also have tech already developed they could reuse, like the pica-x heat shield, the super Dracos, power systems, some of the avionics, etc. The main reason I started this thread was to hear opinions about the feasibility of using an almost untouched Dragon for this role, because if it were feasible it would mean maximizing commonality, and in doing so, minimizing costs, starting with development.

But it's up to SpaceX to decide their path. Elon might think best aiming for something completely different, maybe cheaper to build, or more flexible, or for heavier payloads, etc.

So, answering your question: Do I think they COULD do it cheaper? Yes, I think they could. Will they do it? Who knows.

About building I have less doubt. I'm convinced that, given their business principles, if SpaceX ever design and develop a Mars lander, they are not going to plan to use it only for one mission and then design something different. If they do it, they'll try to use it as many times as possible (not as many opportunities as a launcher but more than one or two, I hope).

If you make more than one item of any design, it follows that some of the costs can be shared, and so the final product tends to be less expensive. That's one other thing I like about repurposing Dragon, that in doing it (if at all doable), even if the final product is not ideal, at least it could be cheaper, because that would give it three roles to play, three different configurations, cargo, crew transport, and Mars lander.

Offline douglas100

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Re: A Dragon derived general purpose Mars lander?
« Reply #68 on: 04/25/2012 10:28 am »
Quote
6 successful landings on Mars to date, one more in the coming.

Hope you're right!

You could argue that the MER and Phoenix are variations of the same design with a different option for the terminal braking and landing. That would put MPL in the same group. So in a sense we already have a kind of general Mars lander. The differences between them were driven by the nature of the payload to be landed.

You could imagine a system using SpaceX technology, like you say and there's no reason that they couldn't do it. Could they do it cheaper? Probably, but that depends on what the mission is.

Quote
The main reason I started this thread was to hear opinions about the feasibility of using an almost untouched Dragon for this role, because if it were feasible it would mean maximizing commonality, and in doing so, minimizing costs, starting with development.

I've already said that I think an untouched Dragon is a poor choice. My (amateur) thoughts about what a Dragon derived design could be like would be:

1. Keep the current Dragon heat shield and mold line
2. Use the current thrusters and Super Dracos for an all propulsive landing
3. Get rid of the pressure vessel and have a backshell which separates
4. Jettison the heat shield before braking to reduce landing mass and allow the super Dracos to point straight down
5. Replace the trunk with a cruise stage.

This means essentially a new spacecraft, but it means the payload is exposed to the Martian environment on landing and can  be offloaded if required.

As for will they do it, as you said, who knows? If SpaceX wish to carry out their own Mars mission I think Mr. Musk will have to dip deeper into his personal fortune. It's difficult to imagine a series of such spacecraft being built at the present time unless some HBP* comes along and pays for it.

(*HBP=Hypothetical Billionaire Philanthropist  :))





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Offline upjin

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Re: A Dragon derived general purpose Mars lander?
« Reply #69 on: 06/11/2012 01:10 pm »
I like this topic.  Since the Falcon Heavy will launch soon and based on the success of the Dragon to ISS, it is possible that additional funding could come from rich investors, various governments, and/or various companies.  Such investors may have a vested interest in Mars.  Not just NASA, but many others.  Per Musk, he is anticipating that there will be significant business for SpaceX in missions to Mars.

Falcon Heavy and Dragon would mean that there is a vehicle to get to and land on Mars, thus it would encourage investment and projects to use them.  Such investment would likely help provide SpaceX with the additional capital to modify their Dragons for various missions.
« Last Edit: 06/11/2012 01:14 pm by upjin »

Online meekGee

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Re: A Dragon derived general purpose Mars lander?
« Reply #70 on: 06/11/2012 01:45 pm »
1. Keep the current Dragon heat shield and mold line
2. Use the current thrusters and Super Dracos for an all propulsive landing
3. Get rid of the pressure vessel and have a backshell which separates
4. Jettison the heat shield before braking to reduce landing mass and allow the super Dracos to point straight down
5. Replace the trunk with a cruise stage.


'sactly right.

Still, they might send a single minimally-modified Dragon in order to validate and qualify subsystems and to be able to incorporate lessons learned into the first Martian lander.

It's not so much for the cost savings since they'll get private funding for such a mission, it's because they can do it much sooner and with less required development.
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Offline douglas100

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Re: A Dragon derived general purpose Mars lander?
« Reply #71 on: 06/11/2012 03:26 pm »

It's not so much for the cost savings since they'll get private funding for such a mission, it's because they can do it much sooner and with less required development.

Will they? From where?
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Offline charliem

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Re: A Dragon derived general purpose Mars lander?
« Reply #72 on: 06/11/2012 04:25 pm »
May I remind you that there are at least 3 different proposals we know of to use Dragon for scientific mission to Mars? Red Dragon, Ice Dragon, and Red Dragon-MSL.

Even if Dragon is not a general purpose mars lander looks like some people think it's good enough as is/will be.

Online meekGee

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Re: A Dragon derived general purpose Mars lander?
« Reply #73 on: 06/11/2012 04:43 pm »

It's not so much for the cost savings since they'll get private funding for such a mission, it's because they can do it much sooner and with less required development.

Will they? From where?

Look at how many rich folks are willing to put funds into developing their own launch technology.   Supporting a Mars mission with an existing rocket and vehicle is a) cheaper, b) less risky, c) quicker, and d) more gratifying.     Of course they'll fund it.

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Offline Jim

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Re: A Dragon derived general purpose Mars lander?
« Reply #74 on: 06/11/2012 05:25 pm »

1.  Look at how many rich folks are willing to put funds into developing their own launch technology.

2.    Supporting a Mars mission with an existing rocket and vehicle is a) cheaper, b) less risky, c) quicker, and d) more gratifying.     Of course they'll fund it.


1.  Not an applicable analogy.

2.  Meaningless. There is no return for investors.

Of course, they won't fund it.
« Last Edit: 06/11/2012 05:26 pm by Jim »

Offline Jim

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Re: A Dragon derived general purpose Mars lander?
« Reply #75 on: 06/11/2012 05:27 pm »

Still, they might send a single minimally-modified Dragon in order to validate and qualify subsystems and to be able to incorporate lessons learned into the first Martian lander.

No, because its viability is not a given

Online wolfpack

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Re: A Dragon derived general purpose Mars lander?
« Reply #76 on: 06/11/2012 05:36 pm »
As much as I like these guys (SpaceX), let's be real. They're not sending anything to Mars. I think sometimes we forget just how hard that is to do.

Elon Musk is an inspiring individual, no doubt, but if the goal is to run a profitable company that may someday be offered for public ownership, then investors are not going to want to hear words like "Mars" or "making life interplanetary". They want to hear things like "backlog" and "book-to-bill". That means launching paying customers' spacecraft into the part of space that they paid to have it put in. And it ain't gonna be Mars.

Online meekGee

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Re: A Dragon derived general purpose Mars lander?
« Reply #77 on: 06/11/2012 05:43 pm »

Still, they might send a single minimally-modified Dragon in order to validate and qualify subsystems and to be able to incorporate lessons learned into the first Martian lander.

No, because its viability is not a given

So you're saying they won't test it because it's not tested...    I can't really argue with that.  :)
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Online meekGee

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Re: A Dragon derived general purpose Mars lander?
« Reply #78 on: 06/11/2012 05:48 pm »

1.  Look at how many rich folks are willing to put funds into developing their own launch technology.

2.    Supporting a Mars mission with an existing rocket and vehicle is a) cheaper, b) less risky, c) quicker, and d) more gratifying.     Of course they'll fund it.


1.  Not an applicable analogy.

2.  Meaningless. There is no return for investors.

Of course, they won't fund it.

It wasn't an analogy, and the two parts of the paragraphs are not stand-alone sentences.  The first is an observation, and the second compares the proposition at hand to it, which makes it both applicable and meaningful.

As for ROI, none of these people are in it for a 5-year ROI.  They do it because they've got more money than they can spend, so they LIKE to do it.

There's no ROI in buying a luxury yacht either, but obviously people do.  It's just that some people find things like funding a Mars mission more gratifying than a yacht. (or they already have one)
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Offline Jim

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Re: A Dragon derived general purpose Mars lander?
« Reply #79 on: 06/11/2012 06:27 pm »

Still, they might send a single minimally-modified Dragon in order to validate and qualify subsystems and to be able to incorporate lessons learned into the first Martian lander.

No, because its viability is not a given

So you're saying they won't test it because it's not tested...    I can't really argue with that.  :)

No, they are going to do it because it is not worth the return

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