Mars Direct vs Mars for Less

[neutrino78x]

Two plans for going to Mars which use ISRU, In Situ Resource Utilization, to reduce cost, are Mars Direct and Mars for Less. Each would send a robotic device ahead of the humans, to generate the fuel and drinking water to return to earth, and then, after it is verified to have generated sufficient amounts of these things, send humans, with only the fuel to go one way.

The difference is that Mars for Less is a plan to do it with existing launchers, such as EELVs, or Falcon 9, whereas Mars Direct calls for a Heavy Launcher, such as the Direct Shuttle Derived Launcher.

So which do you guys think is better and why?

Mars Direct FAQ

Mars for Less Wikipedia

Direct Shuttle Derived Heavy Launcher.

--Brian

 

[neutrino78x]

(a consequence of using smaller launchers in Mars for Less is that you have to do on orbit assembly)

--Brian

 

[bushwhacker]

we'll need to do on orbit assembly anyway may as well start now

 

[neutrino78x]

we'll need to do on orbit assembly anyway may as well start now

well then vote for Mars for Less

--Brian

 

[JonClarke]

Both are flawed.

Both use a low lift entry design which probably won't work for missions of this mass.

Both have excessively small Earth return vehicles

Mars for less uses orbital assembly of a type that is clumsy, ugly but impractical.

Mars Direct has less wrong with it and is therefore less unsatisfactory.

But there are much better proposals than either of these. Mars semi-direct options and those decended from it, in particular the NASA DRM 4.0 and the MarsOz reference mission.

Jon

 

[Astro_Robert]

Heavy launchers are always desireable from a variety of standpoints, so I would vote that way. However, my familiarity with Mars Direct was that it was something that Zubrin was preaching to bypass the Moon and spend zillions to get to Mars, and I like Moon or near Earth objects better as near term exploration targets.

So Heavy Lift, yes

Near term Humans to Mars, no. It is simply too expensive (resource committment is just staggering, even with ISRU) and risky with near term technologies, which is why I wish they would regard constellation as soley a moon/near Earth vehicle and drop the Mars premise completely. If we try to goto Mars in another 20+ years, then we will design a new vehicle more suited to that task.

 

[Polishguy]

Heavy launchers are always desireable from a variety of standpoints, so I would vote that way. However, my familiarity with Mars Direct was that it was something that Zubrin was preaching to bypass the Moon and spend zillions to get to Mars, and I like Moon or near Earth objects better as near term exploration targets.

So Heavy Lift, yes

Near term Humans to Mars, no. It is simply too expensive (resource committment is just staggering, even with ISRU) and risky with near term technologies, which is why I wish they would regard constellation as soley a moon/near Earth vehicle and drop the Mars premise completely. If we try to goto Mars in another 20+ years, then we will design a new vehicle more suited to that task.

Actually, Zubrin proposed using Mars Direct hardware for lunar exploration as well. Cut out the aeroshell and send the ERV with fuel, and you've got a moon base with no new hardware development. And a Congressional committee found that Zubrin's plan would cost something less than $50 Billion, as opposed to Project Apollo, which cost $150 Billion.

As for my own support...

Well, a Mars Direct Hab Module can be launched with 3 Falcon 9 heavy rockets, assuming each rocket sends up 25 tonnes of propellant. The questions of how it would be laid out in this Mars For Less configuration are a bit tougher, but by no means a show stopper. If the Russians could put Mir together with unmanned orbital assembly two decades ago, I believe that components for a Mars mission can be put together in orbit now.

However, a heavy-lift launcher has other benefits. For example, the Shuttle-derived heavy lifter that Zubrin proposes could have payload dimensions of ten meters width, as would the Ares V. A DIRECT style Heavy Lifter would still have more than Falcon 9 does: a full 8 meters of space. Falcon 9, by my memory, has just 5. This can be used for telescopes with bigger sizes than Hubble. A heavy lifter is also useful for unmanned missions to the outer solar system.

So, for the benefit of having a new heavy lifter, I go with Mars Direct.

 

[Valcan]

Heavy launchers are always desireable from a variety of standpoints, so I would vote that way. However, my familiarity with Mars Direct was that it was something that Zubrin was preaching to bypass the Moon and spend zillions to get to Mars, and I like Moon or near Earth objects better as near term exploration targets.

So Heavy Lift, yes

Near term Humans to Mars, no. It is simply too expensive (resource committment is just staggering, even with ISRU) and risky with near term technologies, which is why I wish they would regard constellation as soley a moon/near Earth vehicle and drop the Mars premise completely. If we try to goto Mars in another 20+ years, then we will design a new vehicle more suited to that task.

Actually, Zubrin proposed using Mars Direct hardware for lunar exploration as well. Cut out the aeroshell and send the ERV with fuel, and you've got a moon base with no new hardware development. And a Congressional committee found that Zubrin's plan would cost something less than $50 Billion, as opposed to Project Apollo, which cost $150 Billion.

As for my own support...

Well, a Mars Direct Hab Module can be launched with 3 Falcon 9 heavy rockets, assuming each rocket sends up 25 tonnes of propellant. The questions of how it would be laid out in this Mars For Less configuration are a bit tougher, but by no means a show stopper. If the Russians could put Mir together with unmanned orbital assembly two decades ago, I believe that components for a Mars mission can be put together in orbit now.

However, a heavy-lift launcher has other benefits. For example, the Shuttle-derived heavy lifter that Zubrin proposes could have payload dimensions of ten meters width, as would the Ares V. A DIRECT style Heavy Lifter would still have more than Falcon 9 does: a full 8 meters of space. Falcon 9, by my memory, has just 5. This can be used for telescopes with bigger sizes than Hubble. A heavy lifter is also useful for unmanned missions to the outer solar system.

So, for the benefit of having a new heavy lifter, I go with Mars Direct.

Another reason for a heavy lift rocket is for as was stated a wider cargo bay. Imagine the size a Bigelow Modual could be.

I think as i have said (numerous times ) and many others have said one of the first goals needs to be making a Yard where spacecraft and other objects can be constructed and repaired. Constantly having to make something fit into a predetermined size constrains what can be accomplished. Something like that could also be alot of heap in repairing say a dammaged station modual or a satelite that can still be useful. There could come a time in the future where instead of launching yet another satelite into orbit the same satelite could be continuously upgrades for a far cheaper cost.

 

[Polishguy]

Heavy launchers are always desireable from a variety of standpoints, so I would vote that way. However, my familiarity with Mars Direct was that it was something that Zubrin was preaching to bypass the Moon and spend zillions to get to Mars, and I like Moon or near Earth objects better as near term exploration targets.

So Heavy Lift, yes

Near term Humans to Mars, no. It is simply too expensive (resource committment is just staggering, even with ISRU) and risky with near term technologies, which is why I wish they would regard constellation as soley a moon/near Earth vehicle and drop the Mars premise completely. If we try to goto Mars in another 20+ years, then we will design a new vehicle more suited to that task.

Actually, Zubrin proposed using Mars Direct hardware for lunar exploration as well. Cut out the aeroshell and send the ERV with fuel, and you've got a moon base with no new hardware development. And a Congressional committee found that Zubrin's plan would cost something less than $50 Billion, as opposed to Project Apollo, which cost $150 Billion.

As for my own support...

Well, a Mars Direct Hab Module can be launched with 3 Falcon 9 heavy rockets, assuming each rocket sends up 25 tonnes of propellant. The questions of how it would be laid out in this Mars For Less configuration are a bit tougher, but by no means a show stopper. If the Russians could put Mir together with unmanned orbital assembly two decades ago, I believe that components for a Mars mission can be put together in orbit now.

However, a heavy-lift launcher has other benefits. For example, the Shuttle-derived heavy lifter that Zubrin proposes could have payload dimensions of ten meters width, as would the Ares V. A DIRECT style Heavy Lifter would still have more than Falcon 9 does: a full 8 meters of space. Falcon 9, by my memory, has just 5. This can be used for telescopes with bigger sizes than Hubble. A heavy lifter is also useful for unmanned missions to the outer solar system.

So, for the benefit of having a new heavy lifter, I go with Mars Direct.

Another reason for a heavy lift rocket is for as was stated a wider cargo bay. Imagine the size a Bigelow Modual could be.

I think as i have said (numerous times ) and many others have said one of the first goals needs to be making a Yard where spacecraft and other objects can be constructed and repaired. Constantly having to make something fit into a predetermined size constrains what can be accomplished. Something like that could also be alot of heap in repairing say a dammaged station modual or a satelite that can still be useful. There could come a time in the future where instead of launching yet another satelite into orbit the same satelite could be continuously upgrades for a far cheaper cost.

That's actually what Station and Shuttle were supposed to be for. Station was supposed to have a big Shuttle Fuel Tank docked to the side as a hangar bay for satellites and spacecraft. Shuttle was supposed to go up and fix DoD and NASA satellites. But then the budget cuts...

 

[DarkenedOne]

Another reason for a heavy lift rocket is for as was stated a wider cargo bay. Imagine the size a Bigelow Modual could be.

I think as i have said (numerous times ) and many others have said one of the first goals needs to be making a Yard where spacecraft and other objects can be constructed and repaired. Constantly having to make something fit into a predetermined size constrains what can be accomplished. Something like that could also be alot of heap in repairing say a dammaged station modual or a satelite that can still be useful. There could come a time in the future where instead of launching yet another satelite into orbit the same satelite could be continuously upgrades for a far cheaper cost.

That's actually what Station and Shuttle were supposed to be for. Station was supposed to have a big Shuttle Fuel Tank docked to the side as a hangar bay for satellites and spacecraft. Shuttle was supposed to go up and fix DoD and NASA satellites. But then the budget cuts...

It was not the budget cuts. The space shuttle simply proved to be too unreliable and to expensive to use for fixing satellites. At 1.3 billion per flight very few satellites are worth that much. That includes the Hubble, which costs only $700 million, but that was done more for political reasons.

On top of that you had a 1/50 chance of loss of vehicle and crew.

 

[Valcan]

Another reason for a heavy lift rocket is for as was stated a wider cargo bay. Imagine the size a Bigelow Modual could be.

I think as i have said (numerous times ) and many others have said one of the first goals needs to be making a Yard where spacecraft and other objects can be constructed and repaired. Constantly having to make something fit into a predetermined size constrains what can be accomplished. Something like that could also be alot of heap in repairing say a dammaged station modual or a satelite that can still be useful. There could come a time in the future where instead of launching yet another satelite into orbit the same satelite could be continuously upgrades for a far cheaper cost.

That's actually what Station and Shuttle were supposed to be for. Station was supposed to have a big Shuttle Fuel Tank docked to the side as a hangar bay for satellites and spacecraft. Shuttle was supposed to go up and fix DoD and NASA satellites. But then the budget cuts...

It was not the budget cuts. The space shuttle simply proved to be too unreliable and to expensive to use for fixing satellites. At 1.3 billion per flight very few satellites are worth that much. That includes the Hubble, which costs only $700 million, but that was done more for political reasons.

On top of that you had a 1/50 chance of loss of vehicle and crew.

My whole thing is that you dont need to send the vehicle doing the work back just send the parts etc up to the station on a cheap reliable rocket, either retrieve the satelite or use a vehicle (could have a tug that utilized several different moduals all with specific perposes. All the tug needs to do is connect to the modual and begin the mission . Gets done disconnect. Dock and done. The 2 most dangerous things in space travel are the atmosphere and the shiny red candy button which you should never, ever push.

 

[neutrino78x]

Actually, Zubrin proposed using Mars Direct hardware for lunar exploration as well. Cut out the aeroshell and send the ERV with fuel, and you've got a moon base with no new hardware development. And a Congressional committee found that Zubrin's plan would cost something less than $50 Billion, as opposed to Project Apollo, which cost $150 Billion.

That's exactly what I was going to say. If you want, you can use Mars Direct hardware for the moon also.

The same applies to Mars for Less; the crew hab can be used on the moon.

You want to have space modules be able to be used for as many missions as possible. It is lame to build a whole spacecraft, or series of modules, for one destination, never to be used again.

The Navy doesn't have one ship that can do nothing but go to Europe, another ship that can do nothing but go to Japan, another that can do nothing but go to Australia. Each ship can do multiple missions.

--Brian