Why should we want to go to Mars at this point in time? Given the choice of putting billions into going to Mars or doing something else, why should we go to Mars? It seems to me that there are far better places to put this money.

This entire thread is based on the premise that sending humans to Mars is desirable, and we are discussing how best to get there. The purpose of my comment was to address how NASA should spend its money, not whether it should have the money in the first place.

If you would like to discuss de-funding human spaceflight and/or NASA, I think there are points for and against both, and would be interested to read your thoughts on the matter.

I understand, it's just that your comment made me doubt whether going to Mars is a good idea at all :)

Why I thought that going to Mars might not be a great idea (yet):

NASA's budget is about 17 billion so lets guesstimate that going to Mars will cost 100 billion. It's probably a lot more to establish a colony, let alone a self sufficient colony. What is the benefit of having a colony on Mars? We aren't lacking space on Earth; it would be a lot easier to colonize the Saharan desert than to colonize Mars. Instead that money could go to scientific research (e.g. renewable energy generation, medical research, AI research, robotics research), or to some other cause. Wouldn't that be of much greater benefit to humanity?

If you're looking purely at space exploration it also seems to me that there are better ways to spend that money than to put humans on Mars. For the same money we could probably put a whole bunch of telescopes in space and send several probes/rovers to asteroids/planets/moons.

Even if the ultimate goal is to establish a colony on Mars, it might be a better strategy to build it with robots than with humans...?

I recommend reading the last waitbutwhy post. Also available in audio, which is nice to digest the material if you're doing a few hours of less inspirational work

The "money could be better spent" argument seems kind of silly when you think about how much more money is spent on efforts directly or indirectly related to killing people. As long as that's still a thing, I don't have a word to say about the humanistic benefits of NASA's funding.

Anyway, the point of NASA and space exploration is to inspire people, to fill them with wonder and dreams, and that is invaluable. Humans want to actually go into space, sending robots and telescopes is just in service of that. There are many ways that we could better focus our efforts to solve various Earthly problems, and we're generally doing other things with our time and resources. Of those things, I would say researching space travel is pretty low on the list of targets for redistribution.

>NASA's budget is about 17 billion so lets guesstimate that going to Mars will cost 100 billion. It's probably a lot more to establish a colony, let alone a self sufficient colony.

I would estimate that the constellation/SLS Orion program to Mars or some derivative thereof can be accomplished at a total cost of 50-100 billion USD (inflation adjusted to 2015 equivalent), as NASA projects $18 billon in development costs, and 1.5-2 billion per launch.[1] They are spending 2 billion per year on SLS/Orion, and will continue to do so for 10 years until first flight, followed by ~ one flight per 18 months at a similar cost for 10-15 years. For reference, the space shuttle program cost approximately 200 billion dollars.[2]

SpaceX/Blue Origin/Orbital Sciences could probably accomplish a similar goal with 10-25 billion dollars depending on speed of implementation, success of various reusability schemes, use of higher efficiency drives, and launch system success rates. From memory, I think SpaceX recently said that they could develop their super-heavy launch system in 5 years for 1.5 billion, and I believe Orbital said their system would have a development cost of 2 billion.

Colonization will probably cost more, though Musk has said that he aims to reduce the cost of moving to Mars to $500k USD (inflation adjusted to 2015) with a total colony cost of about $40 billion by about 2050.[3] I am not sure how to evaluate whether this is a worthy objective, but it seems that securing the future of humanity might be worth 0.13% of annual gross world product (100 billion dollars), and SpaceX aims to achieve this goal for much less money.[4]

>We aren't lacking space on Earth; it would be a lot easier to colonize the Saharan desert than to colonize Mars

Colonizing the Sahara desert is intellectually interesting, but there doesn't seem to be much point to the exercise. It is well established that people can live in deserts. Total human population will soon begin to decrease anyway, so overpopulation will not be a problem in the forseeable future, and living in the Sahara does nothing in terms of securing humanity's future against cataclysms.[5]

>Instead that money could go to scientific research (e.g. renewable energy generation, medical research, AI research, robotics research), or to some other cause. Wouldn't that be of much greater benefit to humanity?

It is not clear to me that the government is managing current research funding very well, so I would be most likely to support returning NASA's budget to the taxpayers (in the form of budget and later tax cuts), which are likely to improve everyone's standard of living (all over the world), and allow people to have better day-to-day lives.[6] However, it is very difficult to compare an improvement of daily life on Earth to the establishment of a multi-planetary species. I would likely favor the latter, though I do believe it would be much better if humanity made this great leap without coercing taxpayers (though this is probably one of the less morally problematic instances of government coercion).[7]

>If you're looking purely at space exploration it also seems to me that there are better ways to spend that money than to put humans on Mars. For the same money we could probably put a whole bunch of telescopes in space and send several probes/rovers to asteroids/planets/moons.

I would question this, on the basis that I am not sure what the goal of the robotic and telescopic exploration really is. When you say that human missions to Mars are esoteric and pointless, it is hard to simultaneously argue that it is imperative to figure out what happened long ago in a galaxy far far away or on a planet you never plan on going to. If there is to be exploration and study of space, it seems to me that establishing a multi-planetary presence, and expanding our horizons should be the top priority. In addition to providing inspiration and knowledge to those of us who remain here on earth, those astronauts (and future Martians) will be taking the first steps to securing humanity against disaster, and spreading life throughout the galaxy.

[1] https://en.wikipedia.org/wiki/Space_Launch_System

[2] https://en.wikipedia.org/wiki/Space_Shuttle_program

[3] http://www.outerplaces.com/science/item/9914-elon-musk-s-pla...

[4] https://en.wikipedia.org/wiki/Gross_world_product

[5] https://en.wikipedia.org/wiki/Projections_of_population_grow...

[6] http://eml.berkeley.edu/~dromer/papers/RomerandRomerAERJune2...

[7] https://en.wikipedia.org/wiki/The_Problem_of_Political_Autho...

It's more Congress that wants SLS to continue than NASA.

I agree with you that SLS A.K.A. Senate Launch System is more of a congressional program than a NASA program, but neither NASA nor the executive branch have been vocal in opposing it, and the rest of the 'path to Mars' (as proposed by NASA) is even more wasteful than SLS.

NASA has been pretty vocally against since 2010 or so, here's an example:

http://www.spacepolitics.com/2014/03/28/bolden-and-house-com...

You have to understand that NASA is a big place and they have a public communications aspect with people who's job it is to spread word about what they are doing no matter if it's what they want to be doing or not, so rthat's why you see so much in support.

The best way to tell if it is fluff or real is to look for vague ideas instead of hard timelines.

I agree with you that there is are a wide variety of ideas about SLS and Orion in NASA, but the official policy (and the basis for this thread) is that SLS will take NASA to Mars. In the article you cited, Bolden is saying that he needs commercial crew to be fully funded to enable research on the ISS, which will allow for the use of SLS on trips to Mars. From the article:

>Bolden said that without the ISS, he would recommend that SLS and Orion be cancelled.

SLS and Orion are useless and should be cancelled without respect to what happens with the commercial crew program. SLS or derivatives thereof will not allow for the expoloration or colonization of Mars, the system is already in a cost/scope death spiral, and even if it is completed, it will be too expensive and too unreliable to be used for its intended purpose.

If NASA really wanted to go to Mars, they would propose cancelling SLS, and spending the money on Blue Origin, SpaceX, and Orbital Sciences (and possibly Skylon). BO, SX and OS super-heavy launch systems could be developed for a combined cost lower than SLS', they will have lower specific cost to orbit ($/kg) and they do not have the problems which NASA has with cost and schedule overruns. They could even fund two of the super-heavy launch systems, and use the extra money for launches to do induced low-gravity research, and high-efficiency propulsion research (amongst other things).

Honest question, why do you feel a different super-heavy lift system would be more achievable than the SLS?

NASA hasn't developed a new rocket since the space shuttle, so they simply have no relevant experience. In addition, SpaceX, ULA, and Orbital Sciences have demonstrated an ability to develop space systems much more quickly and reliably than NASA, which usually has cost/scope death spirals, largely due to slow schedules, bureacracy and lack of impetus to move forward. In addition, NASA develops launch systems for a single customer, whereas all the others are trying to develop systems which can be used for a wide variety of customers, meaning that they can amortize development over more launches, as well as offering the opportunity to improve design and manufacturing reliability and cost issues.

SLS is only the latest in a series of system designs which have been cancelled/drastically redesigned.[1] Even if SLS were completed (at over 10 times the cost of any other alternative), it is scheduled for less than one launch per year, which means that it will never demonstrate reliability or achieve economy.

[1] https://en.wikipedia.org/wiki/Space_Launch_System

Agree with leaving the launch system to commercial partners (SpaceX, etc...), but why the need for further ion thruster research as a pre-requisite for a manned Mars mission? Wouldn't a chemical thruster and a Hohmann transfer suffice, at least for the initial few trips?

You're right that ion thruster research is not necessary to enable trips to Mars, but it would make sense to try to reduce time in transit and requirements for launch mass, as well as enable more frequent trips to Mars. Ion (or EM drive) propulsion research could (reasonably) be regarded as tangential, but I would see it as forward progress which will help us to reach and explore Mars.

Failure to perfect high-efficiency propulsion should not be a barrier to Mars travel, but use of these systems would definitely be helpful.