Author Topic: A Dragon derived general purpose Mars lander?  (Read 55562 times)

Offline DaveH62

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Re: A Dragon derived general purpose Mars lander?
« Reply #100 on: 06/12/2012 02:00 am »
but can only happen in 6 years, whereas a minimally-modified one can be launched in 2. 

No, that is my point, they can't do it in 4 years much less two.
TBD

Online A_M_Swallow

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Re: A Dragon derived general purpose Mars lander?
« Reply #101 on: 06/12/2012 02:42 am »
SpaceX listed on a stock market may find that a long term mission with little profit is unpopular with its shareholders.  Fortunately there is an easy way for Elon Musk to solve this problem - set up MarsX.  MarsX can contract SpaceX to build and launch the spacecraft.

Offline rst

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Re: A Dragon derived general purpose Mars lander?
« Reply #102 on: 06/12/2012 04:22 am »
SpaceX listed on a stock market may find that a long term mission with little profit is unpopular with its shareholders.  Fortunately there is an easy way for Elon Musk to solve this problem - set up MarsX.  MarsX can contract SpaceX to build and launch the spacecraft.

After a SpaceX IPO, Musk might still retain enough voting rights to keep control of the company, as Zuckerberg has with Facebook, or (much earlier) Henry Ford did with Ford.  This doesn't necessarily mean a majority of the shares of common stock; both Zuck and Ford did it in part by having a class of "insider-only" shares with enhanced voting rights.  (Elon's certainly aware of these situations, and I think he's at least hinted in public that he's likely to try the same with SpaceX.)

Companies with this sort of arrangement (Facebook now, possibly SpaceX in the future) are still required to regularly disclose information on their financial results and general health.  But if there are shareholders who don't like those reports, they might as well sell; they can complain, but they have no legal recourse.
« Last Edit: 06/12/2012 04:25 am by rst »

Offline go4mars

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Re: A Dragon derived general purpose Mars lander?
« Reply #103 on: 06/12/2012 05:44 am »
whether a Red Dragon style mission should use a near-stock Dragon or a Dragon-derived Mars lander probably comes down to cost vs benefit.
So cost to them is more than just $. 

The incremental cost of another rocket or another capsule, especially when they are masters of their own schedule, is going to be a lot lower.
If they have an assembly line pushing out 20-40 cores per year (they have stated that they want to achieve this in the next few years) then there may occasionally be a time when they have some extra hardware laying around without a customer.  Questions emerge at that point:.

1) What's better value: To leave the hardware in a warehouse until a customer maybe shows up?  Or to collect impressive publicity and advertising (such as an X-prize competition on a donated Mars launch)?  Will the current excess hardware be obsolete soon anyway? 

2) Would Elon himself be the customer and finally launch "Mars Oasis"?

3)  Consider a "standing army" versus a "marching army".  Keep them moving and accomplishing things or they'll be more expensive and less keen. 
« Last Edit: 06/12/2012 10:19 pm by go4mars »
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Offline douglas100

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Re: A Dragon derived general purpose Mars lander?
« Reply #104 on: 06/12/2012 08:58 am »
If you can tell me who the customers are for these "20 to 40 cores per year" I'll start to believe your premise. SpaceX are smart people. There is no way they would build a large number of cores without customers.
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Online Lampyridae

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Re: A Dragon derived general purpose Mars lander?
« Reply #105 on: 06/12/2012 11:04 am »
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.

My (amateur) thoughts:

1. Not going to happen. CO2 atmosphere poses very different issues to an N2 one. This is why Viking and on used 70 degree cones. The Russians thought Mars had an N2 atmosphere; this is how they lost their early probes.
2. Would require some degree of modification due to supersonic starts, but possible. Fuel requirement would be large.
3. Likely in any case.
4. It would be dumb not to jettison the heat shield.
5. Better to mount the trunk up front and launch inside a fairing.

All this really gets you is a MSL-sized payload, because we still need better chutes, inflatable decelerators and other tricks to land anything bigger... and as Jim says - where is the market?

My (professional) thoughts:
Aiming for Mars is more about branding at the moment than company goals. Yes, in 20 years SpaceX may be in a position to do such things. Where there is no market, one create a market. But not too early - anybody remember a thing called an Apple Newton?
« Last Edit: 06/12/2012 11:05 am by Lampyridae »
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Online wolfpack

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Re: A Dragon derived general purpose Mars lander?
« Reply #106 on: 06/12/2012 01:15 pm »
If they have an assembly line pushing out 20-40 cores per year (the have stated that they want to achieve this in the next few years) then there my occasionally be a time when they have some extra hardware laying around without a customer.

No, they won't. Do Boeing or Airbus have extra airplanes laying around waiting for a customer?

Offline go4mars

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Re: A Dragon derived general purpose Mars lander?
« Reply #107 on: 06/12/2012 01:28 pm »
I don't know.  But just about every type of factory occasionally has surplus inventor to deal with.  Cars, toys, furniture...

It sounds like this is the production model for SpaceX, though I'm not saying I know for sure either way.
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Offline Jim

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Re: A Dragon derived general purpose Mars lander?
« Reply #108 on: 06/12/2012 02:49 pm »
I don't know.  But just about every type of factory occasionally has surplus inventor to deal with.  Cars, toys, furniture...

It sounds like this is the production model for SpaceX, though I'm not saying I know for sure either way.

No, production is order based.

Offline meekGee

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Re: A Dragon derived general purpose Mars lander?
« Reply #109 on: 06/12/2012 04:36 pm »
I don't know.  But just about every type of factory occasionally has surplus inventor to deal with.  Cars, toys, furniture...

It sounds like this is the production model for SpaceX, though I'm not saying I know for sure either way.

No, production is order based.

In modern facilities, correct.  But the production capacity is there.  So the incremental cost to make one more article for internal consumption is low, especially when flex-scheduled to a time when orders are low.
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Offline Jim

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Re: A Dragon derived general purpose Mars lander?
« Reply #110 on: 06/12/2012 04:42 pm »

In modern facilities, correct.  But the production capacity is there.  So the incremental cost to make one more article for internal consumption is low, especially when flex-scheduled to a time when orders are low.

 Which is applicable to any production facility, which is meaningless since it still doesn't mean it will happen.  The cost will still be too high.

Offline meekGee

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Re: A Dragon derived general purpose Mars lander?
« Reply #111 on: 06/12/2012 04:51 pm »
Which is applicable to any production facility, which is meaningless since it still doesn't mean it will happen.  The cost will still be too high.

Yes and no - it's applicable to any production facility, but useful only when the producer is also the consumer, and only when the producer is vertically integrated, or else most of the benefit is lost.

Whether it's too high for them is TBD.  It depends on what value *they* attribute to a "as soon as possible" Mars mission.
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Offline Jim

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Re: A Dragon derived general purpose Mars lander?
« Reply #112 on: 06/12/2012 05:07 pm »
but useful only when the producer is also the consumer,

They are no more the consumer than ULA is for Atlas or Delta

Offline meekGee

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Re: A Dragon derived general purpose Mars lander?
« Reply #113 on: 06/12/2012 05:31 pm »
but useful only when the producer is also the consumer,

They are no more the consumer than ULA is for Atlas or Delta

I read this as saying that SpaceX are not interested in using its rockets for their own Mars missions - yes?
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Online wolfpack

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Re: A Dragon derived general purpose Mars lander?
« Reply #114 on: 06/12/2012 06:09 pm »
I don't know.  But just about every type of factory occasionally has surplus inventor to deal with.  Cars, toys, furniture...

It sounds like this is the production model for SpaceX, though I'm not saying I know for sure either way.

Maybe for the "pieces-parts" makers if they have order cancellations, but not for a systems integrator. No one starts building an airplane without signed orders for said airplane. I'm certain the same applies for spacecraft and launch vehicles.

Another thing to consider is that, if SpaceX becomes publicly owned, it will have a Board of Directors that has to approve funding for projects (in a broad sense). If there's no return on money spent flying to Mars, then why would they approve it?

SpaceX has enough on their plates right now with redesigning F9, meeting CRS obligations, and competing for CCDev on its "anything-but-even" playing field.

Offline docmordrid

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Re: A Dragon derived general purpose Mars lander?
« Reply #115 on: 06/12/2012 07:08 pm »
I don't know.  But just about every type of factory occasionally has surplus inventor to deal with.  Cars, toys, furniture...

It sounds like this is the production model for SpaceX, though I'm not saying I know for sure either way.
>
Another thing to consider is that, if SpaceX becomes publicly owned, it will have a Board of Directors that has to approve funding for projects (in a broad sense). If there's no return on money spent flying to Mars, then why would they approve it?

As previously noted ad nauseum, even if SpaceX goes IPO there can issue both voting and non-voting stock. If Musk holds 50.1% of the voting stock, even if it's only 10% of all the stock sold, he retains total control of the company. .

Quote
SpaceX has enough on their plates right now with redesigning F9, meeting CRS obligations, and competing for CCDev on its "anything-but-even" playing field.

Sounds like v. 1.1 is about finished given they're going to fly it with flt. 6, and with 1,800+ people and still hiring I find it difficult to believe they can't walk and chew gum.
« Last Edit: 06/12/2012 07:12 pm by docmordrid »
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Offline charliem

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Re: A Dragon derived general purpose Mars lander?
« Reply #116 on: 06/12/2012 10:20 pm »
Very interesting this morning presentations by John Karcz from Nasa Ames (min 32:00) and M. Rover? from JPL (min 42:24) on Dragon missions to Mars.

Looks I'm not the only one that thinks Dragon looks promising as a delivery platform to Mars, at least for medium sized scientific missions.

I'd like to highlight a few points (words taken from the video between quotation marks, the rest is mine):

- About Falcon Heavy and Dragon mods needed to launch to Mars "there are some changes we should have to be made but ... they aren't too bad, they're pretty straightforward" (min 35:40).

- As we know Dragon needs to prove a number of its [yet] theoretical capabilities, but my personal impression about the Nasa personnel doing the presentations is that they are non as skeptical as some over here ... ;D

- As currently planned Ice-Dragon would land a 1 mT payload at an altitude of -3 km (MOLA ref.), but "should be able to deliver quite more than that" (min 41:10). And it could also land that tonne as high as -1.3 km (min 49:15), and achieve a 10 km accuracy (using MSL guidance techniques).

- Supersonic retro propulsion is now just TRL 2 and is the main worry for the mission planning (min 50:40).

- Dragons heat-shield is expected to be able to endure a 6 km/s entry into the martian atmosphere.

- Red Dragon's ballistic coefficient will be 450 kg/m2 (min 48:06) (add entry mass 7.2 km/s and diameter 3.7 m, and that gives an hypersonic Cd of ~1.5).

- The SuperDraco engines will start only 800 m from the surface, while the capsule is doing mach 2.24. Deceleration will reach 7 g.

- For payload deployment the three apertures of a Dragon capsule (instrument bay included) should suffice for many things but if that's not enough, and given that the shell of the capsule was designed for containing the pressure of a full atmosphere and for these mission that's not a worry, it should be possible to "put significant holes in that capsule with fairings over them ..."  (min 01:25:40).

- Dragon's propellant capacity "is modular and they have the capacity to put quite a bit of propellant in the vehicle ...". By now they are considering 1.9 mT and that's enough for the missions considered (01:28:10).

- The superDracos "have a very, very wide [throttling] range" (01:29:00) (according to the previous presentation at least 5%-100%).

And there were more interesting things, but that's enough for one post.

EDIT: spelling & grammar
EDIT2: mach 2.24 before landing, not 2.24 km/s
« Last Edit: 06/13/2012 12:00 am by charliem »

Offline go4mars

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Re: A Dragon derived general purpose Mars lander?
« Reply #117 on: 06/12/2012 10:24 pm »
if SpaceX becomes publicly owned, it will have a Board of Directors that has to approve funding for projects (in a broad sense).
SpaceX already has a board of directors.  The dominant holders of voting shares select the directors.  Unsurprisingly, 2 of the directors have the last name "Musk". 
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Offline go4mars

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Re: A Dragon derived general purpose Mars lander?
« Reply #118 on: 06/12/2012 10:28 pm »
just about every type of factory occasionally has surplus inventory to deal with... It sounds like this is the production model for SpaceX.
Maybe for the "pieces-parts" makers if they have order cancellations, but not for a systems integrator.
Which would you define SpaceX as? 

I would suggest that they are essentially both.  I don't know exactly what they buy externally, but walking around their factory convinced me that it probably isn't much.
« Last Edit: 06/12/2012 10:30 pm by go4mars »
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Offline Robotbeat

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Re: A Dragon derived general purpose Mars lander?
« Reply #119 on: 06/12/2012 10:32 pm »
Very interesting this morning presentations by John Karcz from Nasa Ames (min 32:00) and M. Rover? from JPL (min 42:24) on Dragon missions to Mars.

Looks I'm not the only one that thinks Dragon looks promising as a delivery platform to Mars, at least for medium sized scientific missions.

I'd like to highlight a few points (words taken from the video between colons, the rest is mine):

- About Falcon Heavy and Dragon mods needed to launch to Mars "there are some changes we should have to be made but ... they aren't too bad, they're pretty straightforward" (min 35:40).

- As we know Dragon needs to prove a number of its [yet] theoretical capabilities, but my personal impression about the Nasa personnel doing the presentations is that they are non as skeptical as some over here ... ;D

- As currently planned Ice-Dragon would land a 1 mT payload at an altitude of -3 km (MOLA ref.), but "should be able to deliver quite more than that" (min 41:10). And it could also land that tonne as high as -1.3 km (min 49:15), and achieve a 10 km accuracy (using MSL guidance techniques).

- Supersonic retro propulsion is now just TRL 2 and is the main worry for the mission planning (min 50:40).

- Dragons heat-shield is expected to be able to endure a 6 km/s entry into the martian atmosphere.

- Red Dragon's ballistic coefficient will be 450 kg/m2 (min 48:06) (add entry mass 7.2 km/s and diameter 3.7 m, and that gives an hypersonic Cd of ~1.5).

- The SuperDraco engines will start only 800 m from the surface, while the capsule is doing 2.24 km/s. Deceleration will reach 7 g.

- For payload deployment the three apertures of a Dragon capsule (instrument bay included) should suffice for many things but if that's not enough, and given that the shell of the capsule was designed for containing the pressure of a full atmosphere and for these mission that's not a worry, it should be possible to "put significant holes in that capsule with fairings over them ..."  (min 01:25:40).

- Dragon's propellant capacity "is modular and they have the capacity to put quite a bit of propellant in the vehicle ...". By now they are considering 1.9 mT and that's enough for the missions considered (01:28:10).

- The superDracos "have a very, very wide [throttling] range" (01:29:00) (according to the previous presentation at least 5%-100%).

And there wer more interesting things, but that's enough for one post.

Thank you!

The large increase in available propellant (versus the other Dragons) and the very high velocity at initial retropropulsion does answer some of the criticisms pretty strongly.

Also, the 7gee acceleration means that 1) they may have very low gravity losses) and 2) they might be planning on sticking the landing (ballsy).
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