Looking for civil debate on Moon vs. Mars

[scottb50]

No. An alternative to Mars Direct is developing other propellent sources than Mars. Roboticly mined lunar propellent could be exported to EML1 and then to LEO.

Then the route to Mars would be:
Earth surface to LEO: 9 km/sec
LEO to EML1 3.8 km/sec
EML1 to TMI .5 km sec

TMI (Trans Mars Injection) from LEO is 3.6 km/sec.

Developing the Martian moons as propellent sources would enable fully fueled ships at low Martian orbits. This would simplify some of the thorny Martian EDL issues.[/quote]


There is no reason to go anywhere else but LEO and then to your destination. It would take nearly the same amount of energy to get to the orbit of the first waypoint as getting to the destination. Stop in another orbit, refuel and reboost isn't worth the bother when you can send up multiple supply payloads to build a rather large vehicle.

[HopDavid]

There is no reason to go anywhere else but LEO and then to your destination.

Without propellent depots: 15 to 20 km/sec total delta V budget. This mandates huge, complicated disposable rockets.

With depots: Max delta V leg is Earth to LEO which is about 9 km/sec. Then legs between depots are in the 3 to 4 km/sec delta V range. 4 km/sec delta V budgets allow simpler, less expensive reusable interplanetary craft.

It would take nearly the same amount of energy to get to the orbit of the first waypoint as getting to the destination.

Actually delta V for LEO to EML1 is more than TMI. Takes about 3.8 km/sec to get from LEO to EML1. Only takes 3.6 for Trans Mars Insertion (TMI)

Stopping at propellent depots doesn't reduce total delta V, it actually increases it.

Those who point at this fact show that they just don't get it.

Propellent sources along the way break up the exponent in the rocket equation. Instead of designing a rocket for e^(15/4.46) - 1 propellent to dry mass ratio, You bust it into legs:

Earth to LEO: e^(9/4.46) - 1
LEO to EML1: e^(3.8/4.46) - 1
LEO to Deimos: e^(3/4.46) - 1
Deimos to Phobos e^(.8/4.46) - 1
Phobos to Mars atmosphere grazing periapse: e^(.6/4.46) - 1

Now the first leg, Earth to LEO, is the hardest. A 9 km/sec delta V budget and abuse from a thick atmosphere. It's possible this will always require multi-stage expendable rockets.

The next three legs are a completely different story. Moving between LEO and Phobos could be accomplished in legs of 3.8 km/sec or less. LEO, EML1, Deimos and Phobos all lack atmospheres.. They do not need robust structures to endure the abuse of re-entry. They don't need thermal protection, ablation shields, or parachutes. This substantially reduces mass and failure modes.

The final leg is more difficult. Perhaps it's possible to design a reusable Mars Lander that doubles as a Mars Ascent Vehicle if its departure and destination points are Phobos and Mars surface. Certainly a fully fueled ship from Phobos would have an easier time than an empty ship that must shed 5.7 km/sec completely with aerobraking. Martian EDL issues are another set of problems that are sproinged away with a wave of the Good Zubrin fairy's wand.

Stop in another orbit, refuel and reboost isn't worth the bother when you can send up multiple supply payloads to build a rather large vehicle.

I said nothing about building a vehicle in orbit.

I am talking about setting up propellent mining on the Moon, Phobos and Deimos as well as propellent depots at EML1, Phobos and Deimos.

To get lunar propellent from the moon to EML1 takes 2.5 km/sec. A reusable lunar lander/ascent vehicle for travel between EML1 and the lunar surface is doable, in my opinion.

[Spacebeliever]

Certainly our generation of cut-throat politicians and entrepreneurs can imagine a greater venture then returning to the same place visited four decades earlier. Has this generation lost the drive their parents had to attempt the lunar landings? Are we wishing to relive past glories, so unimaginative and reliant on our computers and cars we've forgotten our nation's dexterity and ingenuity? Well, NASA is too afraid to leave orbit, someone might get hurt. That wild audacity which drove explorers and pioneers to settle this land we inhabit today, sure doesn't thrive in the blood of our fractured politicians. This is the 21st Century, and it's time we reached further than circling the Earth, isn't it?
It's too expensive you say. Feed the poor. “A Coalition of the Willing” could be found to share research and expenses on a Mars Mandate. Cut out NASA and government incompetence than any plan is suddenly much cheaper. Obama could do well to call for the formation of a World Space Organization and show his willingness to cooperate on a grand human endeavor. It would be a positive legacy to leave our children instead of the ruined planet and money worshiping ways we teach them now. Mars beckons, ladies and gentlemen, packed with challenge and filled with unfathomable secrets and possibilities, it is the salvation of our nation, believe it or not. We as the super power have much to learn on sustainable living, that much is apparent just look at our deficit. These lessons could be learned on Mars. Declaring a mission to Mars by 2020 would invigorate our slumbering economy and add some spark to NASA and the international space effort. Who knows, the knowledge and experiences gained on Mars could inspire our children into dreaming bigger than a 200 MB I-pod.
If we returned to the moon before Mars, it will prove we reached our nation's apex 40 years ago, and believe it or not, are now in decline.

[SpaceXFanMobius57]

I want to be radical and declare we should form a floating colony in the atmosphere of Venus since its doable witht he right techniqes, but thats not the subject.

The way things are going the first person on Mars will probably not be American, or not a NASA employee anyway. Russia's President called on his nation to build a ship to go to Mars, i hope they are sucessful so our space program will get a huge boost from suprized American politicians.

[HopDavid]

Certainly our generation of cut-throat politicians and entrepreneurs can imagine a greater venture then returning to the same place visited four decades earlier.

Mining lunar propellent and exporting it to EML1 and LEO propellent depots was not done four decades earlier.

[HopDavid]

The way things are going the first person on Mars will probably not be American, or not a NASA employee anyway.

The way things are going, the first person on Mars will be a purple leprechaun. That is - nonexistent.

Russia's President called on his nation to build a ship to go to Mars, i hope they are sucessful so our space program will get a huge boost from suprized American politicians.

Russia's going to do it. Musk is going to do it. Or maybe India, China, ESA or Japan. How long have I been hearing this? About as long as they've been saying commercial fusion power is just around the corner.

[bluegrassgazer]

Obama could do well to call for the formation of a World Space Organization and show his willingness to cooperate on a grand human endeavor. It would be a positive legacy to leave our children instead of the ruined planet and money worshiping ways we teach them now. Mars beckons, ladies and gentlemen, packed with challenge and filled with unfathomable secrets and possibilities, it is the salvation of our nation, believe it or not. We as the super power have much to learn on sustainable living, that much is apparent just look at our deficit. These lessons could be learned on Mars. Declaring a mission to Mars by 2020 would invigorate our slumbering economy and add some spark to NASA and the international space effort. .

I think this is a terrific idea and would show some real leadership on the President's part. It seems that any large space endeavor now needs the support of the planet (yes even China and India) to work. Now which would be more difficult: Getting to Mars or getting the nations of planet Earth to agree on how to do it?

Who knows, the knowledge and experiences gained on Mars could inspire our children into dreaming bigger than a 200 MB I-pod.

A 200MB I-pod would be a nightmare

If we returned to the moon before Mars, it will prove we reached our nation's apex 40 years ago, and believe it or not, are now in decline.

If we did this as you described above, and as a mere stepping stone to Mars and beyond, I don't see the downside. IMO the more heavenly bodies we have practice landing on, and the more flights we have out of LOE, the better prepared we will be to defend the planet in the event of a rouge asteroid or comet.

[yevaud]

A 200MB I-pod would be a nightmare

Yeah, I have a 25 MB music collection, and I virtually can't even choose what to listen to, there's so much.

[HopDavid]

If we did this as you described above, and as a mere stepping stone to Mars and beyond, I don't see the downside. IMO the more heavenly bodies we have practice landing on, and the more flights we have out of LOE, the better prepared we will be to defend the planet in the event of a rouge asteroid or comet.

The advantages of the moon are more than just providing experience.

Getting lunar propellent to EML1 takes about 2.5 km/sec:


Trans Mars Insertion (TMI) from LEO is 3.6 km/sec.
TMI from EML1 totals about 1.1 km/sec


A fully fueled ship launched from EML1 has a 2.5 km/sec advantage over a fully fueled ship launched from LEO.

Not only do orbital depots and lunar propellent make Mars trips more doable, they make trips to asteroids and comets more doable.

[Eman_3]

I grew up reading a lot of fascinating and imaginative science fiction. One picture some painted was a permanent, self-sustaining manned colony on Mars, something that appeared realistic and romantic. I do hope that one day it comes to pass. That's my utimate goal, the end game for the beginning of mankind's steps out of our local solar system and eventual travel to far stars.

Right now only Mars or the Moon appear as the only celestial bodies we are capable of reaching, any other canditates such as Europa are just too far away, and anyways, we need to be able to master Mars before trying to extend our reach.

I have carefully read all posts in this thread, and although very informative and entertaining, almost all posters have operated on the assumption that space exploration is a vacuum occupied solely by the USA. But external forces and politics will most likely be the factors that determine who first steps on Mars, and when.

India and China have roadmaps for eventual manned missions on Mars. Russia does not presently have a roadmap or hard plans for a manned mission to Mars, but if there's a way, they will go for it. Other nations such as the EA, Japan, Brasil, and Canada have modest ambitions too, and are willing to be involved or partnered in such proposed missions.

The scenario I see unfolding is that the USA is stuck in internal bickering and stagnate until another nation has begun serious work towards a manned Martian mission. Then, and only then will the population become interested and motivated, and the politicians involved enough to give proper support towards a manned mission to Mars. Once again, competition against another nation for national pride would be the driving force, as it was in the Moon race.

On the political roadmap, Mars would be the target. But as mentioned before, the military has a big voice in determining the direction space exploration and budget money goes. And for them, Mars means nothing. Low earth orbit is the battleground, and the Moon is considered the high ground. Although it appears that it is impractical to fight from the Moon, it has other uses, such as a base for reconnaissance, and if nothing else, to deny any potential enemy the Moon. It's not as much as what the US military can do from the Moon, but the potential and imagined threats other hostile nations can develop and impliment from the moon.

Space exploration is best done by small steps, this is the proven method. For instance, all the Gemini missions were just preparation for Apollo. Such skills such as rendezvous, docking, and spacewalks were learned by Gemini, each one step at a time. The ISS just didn't spring up overnight, such missions such as Skylab and Mir paved the way. The same applies to the Moon or Mars. We have been to the Moon, and it would be easier to re-learn the lessons from Apollo and get back to the Moon than to go to Mars.

Mars is a huge step, and I do wonder whether our reach exceeds our grasp at present.

I also question whether it is valid to risk the lives of human beings, do they have to go to Mars when we may have robots that can fulfill the mission requirements?

Notwithstanding my comments, it will be politics and external forces that will drive any effort by the USA to go to Mars or the Moon. But because some other nation(s) have Mars firmly on their sights, the USA will be forced to compete against them, because of national pride. Then, just as in the days of Apollo, public interest will dissipate, and the competitors will be the ones to establish a permanent, self-sufficient Mars colony. Probably the Chinese.

[Booban]

There is only one country that can threaten American predominance in space, and that is the same country that can end it on earth too. That country is China.

Russia is still a basketcase, though smart enough to have us pay them to dismantle their nuclear subs while they spend to make new missiles to go on their subs.

Europe and India are democracies and therefore answerable to it's electorate who just don't give a damn about space, apart from a few loonies at internet sites like space.com. A minor side note however is this article: http://www.flightglobal.com/articles/2009/11/03/334293/european-union-plans-3-billion-a-year-human-exploration.html which indicates the EU raising its space budget to almost 9 billion USD (NASA is 17-18 billion) for a sample return mission to mars. This is possible because the EU is only barely a democratic institution.

China can do whatever it wants to, its as simple as that. And it already said its going for Mars (edit. I mean moon!). So wheres the 'new moon race'? USA is doing a ruskie and saying they don't even have a plan to go at all.

Did you know Toyota pulled out of formula 1?

Why did I mention that? Because Space is like formula 1, sure the research gained by competing keeps you sharp, but if for some other reason you find yourself in decline, its the first to get axed.

[HopDavid]

India and China have roadmaps for eventual manned missions on Mars. Russia does not presently have a roadmap or hard plans for a manned mission to Mars, but if there's a way, they will go for it. Other nations such as the EA, Japan, Brasil, and Canada have modest ambitions too, and are willing to be involved or partnered in such proposed missions.

A parallel development in the Russia U.S. space race in the 60s was development of ICBMs. Of course a nation that the capability of reach orbit and/or the moon could also deliver inter continental misslles.

What would motivate a space race in the 21st century? If Mars conferred some sort of commerical or military advantage, I imagine it would be vigorously pursued. But that is presently not the case.

With present infra structure, only Heavy lifters can take humans to the moon or Mars. The high price tag of Ares V or similar vehicles excludes most players. The league is restricted to the U.S., China, maybe the E.U. and Russia.

However, with propellent depots and multiple sources of propellent, mega rockets are no longer a pre-requisite. Enabling a small rocket architecture would allow a lot more players to participate.

[Eman_3]

There is only one country that can threaten American predominance in space, and that is the same country that can end it on earth too. That country is China.

Russia is still a basketcase, though smart enough to have us pay them to dismantle their nuclear subs while they spend to make new missiles to go on their subs.

Europe and India are democracies and therefore answerable to it's electorate who just don't give a damn about space, apart from a few loonies at internet sites like space.com.

I respectfully disagree on a few nations.

Russia may have organizational problems, but they do have a lot of technology, and they are selling a lot of it. Making money and forging business alliances. If Russia does decide to go to the Moon or Mars, they have the capability to do it.

India's history of space development is a long, but progressive one. Initially it was solely for national needs. They purchased satellites, and the launch service. Eventually India developed their own launchers, and also construct their own satellites. The Chandrayaan-1 mission truly reflects the capabilities and direction in the exploration of space by India. The Chandrayaan-1 mission was 100% Indian. The launcher and satellite were designed and constructed in India. Do not count out India, they now posess the potential do do a Mars mission. Personally, I'm very impressed by the PSLV.

[John_with_a_B]

Great job MeteorWayne. Just like herding cats...

[EPGrondine]

I don't think you can have a civil debate on Moon vs. Mars.

You have seen it asserted that China is interested in Mars. It is not.

Some people can not stop living in the 1950's. Mars is not Earth like, and the transportation costs are horrendous.

The only compelling reason for going to the Moon is to build man tended comet and asteroid impactor detection systems.
Whoever provides that service will take the leading role in space.

Others can not stop living in the 1960's, when the US went to the Moon alone.

Construction of such impactor detection systems is what I think is the main focus of China's long term space planning right now. They will do it alone if they have to, but would prefer not to, and likely won't have to. There are other nations besides the US.

The CZ5 will be the cheapest launcher to orbit, and will be capable of fulfilling China's heavier launch needs.

That leaves the US with the option of engaging or loosing any leadership role in space.

E.P. Grondine
http://manandimpactsintheamericas.blogspot.com/

[neutrino78x]

Well, I would argue that the Moon should not be commercially developed, because it orbits the Earth, therefore it should be treated like Antarctica. I would use the Moon for telescopes, both radio and optical and infrared.

I would say that the place for commercial development is Mars, Asteroids, etc. Mars is the closest object with an atmosphere and significant land area and other natural resources.

While I would use Mars Direct, Robert Zubrin's plan, to go to Mars, I would modify it to the extent that I would want the modules to be able to be reconfigured and sent to an asteroid instead, with the same launch vehicle. Thus, while the focus would be Mars, you would retain the capability to go to other objects as needed/desired.

Also you would want some kind of program whereby private colonizers on Mars are sponsored or supported somehow.

--Brian

[kelvinzero]

Hi Neutrino,

Why is the fact that the moon orbits the earth an argument not to develop it?

I would put that as the prime advantage of the moon for commercial development.

[Space_Invaders]

I don't think there should be a debate in this respect: both can be done and in fact, both can be seen as different steps in one same logical progression. Nevertheless, I believe we could get to the Moon and Mars quicker if we stopped sending probes to silly places like Pluto or Mercury. Even if New Horizons and MESSENGER provided us with the last drop of information existing about these places, we wouldn't be going there, and it would have hardly any use for us. Of course we would have learnt a lot, but information should also have a practical aspect.

Why don't we use this money, time and resources to prepare the places where we can actually go? Like sending a rover to Mars which actually moves faster than a darn turtle, so that it can map the places most suited for human colonisation? Or dropping a few small climate stations all around the planet so we can have a true idea of the climates and seasons in the different regions of Mars? Or sending a solar-powered airplane to Venus which can fly continuously above the cloud cover?

When expanding throughout the Solar System, we will first move to those places which are closer to us. Thence, there is little point in wasting resources in faraway places which, after all, will still be there if we decide to go there in a few decades/centuries.

[Booban]

Well said space invader. I agree that we need to focus our limited resources on practical things, but what would that be? Why is knowing the seasons and mars and venus' atmosphere practical? If we are going to colonize them yeah, but most people would say that that is fanciful, not practical. Going to a nearby planet doesn't have to be more practical going to a distant one, it depends on what we are going to do there.

We should figure out practical goals instead and learn how to make them feasible. Like mining, space based solar power or EPGrondine's idea on comet and asteroid impactor system (whatever that is(why do we want to know about that Grondine?)).