NASA's Mars Plan

[Enorats]

So, I came across this article tonight discussing NASA's plans for a mars transfer vehicle.

https://arstechnica.com/science/2017/03/for-the-first-time-nasa-has-begun-detailing-its-deep-space-exploration-plans/

They want to build a small station in cislunar space, then.. eventually build a transfer vehicle like 10 years later that they needed that station for some reason to build. To be honest, I'm really not too clear on what the purpose of the "gateway" is.

I absolutely love how slide 7 says "8.4m fairing for SLS cargo to be provided through innovative procurement methods". So.. found lying by the side of the road?

[Wjolcz]

I too don't think a gateway station is needed. My only guess why they actually need it is for hardware/tech and the purpose of doing something. I don't know how true this is but I remember someone saying that if NASA spends only a little they will get around the same amount of cash next year. So by that logic a cislunar station would mean massive boost in funding by the government which would make a Mars mission very much possible. 

[kunok]

We need a "deep space" habitat before doing interplanetary travel. Cislunar space is far outside the magnetosphere, it checks.

We need a substitute of the ISS, it also checks

It makes a lot of more sense than you think, the part that doesn't make sense is the mars trip, but that hasn't sense anyway with the current budget. I'm sorry to say that any plan for a mars trip is just plain unrealistic without a big increase in budget, the rocket is the smaller of the problems.

[Enorats]

But that's the thing.. why do we need a "deep space habitat"? Simply to test how well equipment works outside the magnetosphere? There are simpler ways to do that. Why do we need a replacement for the ISS? The only purpose it really serves is to give NASA a reason to funnel money into commercial programs.

 

We have no use for a station at the L2 point (where they've discussed placing such a station before), or anywhere outside LEO. If you're leaving on a trip to Mars you're leaving from LEO, not someplace far off or god forbid lunar orbit. Going to lunar orbit takes nearly as much delta-v as Mars orbit.

It makes more sense to me to send up the transfer vehicle (what they planned for the early 2030's) and test that in lunar orbit with an orion capsule as a lifeboat for emergencies. A second such vehicle could be sent up (or the first brought back to LEO and refueled, something never attempted), and we could then be on our way to Mars. The station serves no purpose.

[SuperFastJellyfish]

1 hour ago, Enorats said:

Why do we need a replacement for the ISS?

Here's a list of all the experiments performed on the ISS.  After the ISS is decommissioned next decade, we will need another to continue experiments like these in a harsher environment.  An environment that humans will have to live in on the many month transfer to Mars(or on the Moon).  Manned spaceflight is hard, and I think it should be done in baby steps.  We need to learn the pitfalls and create solutions before we send people on a transfer that we aren't sure they can survive in.  Hundreds of deep space experiments make more sense than rushing for boots on Mars, IMO. 

Edit:  After this next station is done doing its thing we should install a research base on the Moon.  Mars is so far down the human spaceflight pipeline in my view that I would place it in the 2100s.

Edit2:  And, yes, using an L2 station as a gateway to anywhere but that station is pointless.   

Edited March 29, 2017 by SuperFastJellyfish

[JayPee]

3 hours ago, Enorats said:

why do we need a "deep space habitat"? Simply to test how well equipment works outside the magnetosphere? There are simpler ways to do that.

Like what?

[Ultimate Steve]

Although some people criticize their plan, it's way better than having no plan, which is what they had until a short while ago.

Anything space related I'm down for. Except orbiting nuclear silos. Unless we were in the middle of an alien invasion or something.

 

Speaking of plans, part of me sometimes wonders how much sooner we could get to Mars if we took all of the major space agencies and combined them together. SpaceX's and Blue Origin's focus on reusability and cost effectiveness, ULA's safety record, EVERYONE's engineers, NASA's infrastructure, and the budget of the US military. Plus a whole bunch of other things I forgot. If everything went absolutely perfectly and everyone was in on it, then there is a possible future in which we will land on Mars in 2020.

But, we live in an imperfect world and we will have to live with what we've got! And now NASA has a slightly larger plan, and we do have the history making launch tomorrow...

 

[Bill Phil]

A gateway station is incredibly useful. It's a higher energy orbit. But we can put things there that we're not comfortable with having in LEO. Like an asteroid, for example. Not to mention that it puts you on the fast-track to the Interplanetary Transport Network. Coming back from Mars, it would be far easier to brake into a highly elliptical orbit that then takes you to the gateway station than to brake into LEO, or, rather, we don't need as thick of an aero-shield. It also lets us do the trips in hops. For example, the delta-V to get to L-2, from LEO, is pretty big. But, if you put a fuel depot there, and design your spacecraft to refuel, you get more total delta-V for the mission, and it's still pretty close...

Basically, you spend a lot of energy to get to the edge of the gravity well, and then put a large facility there to facilitate exploration.

Edited March 30, 2017 by Bill Phil

[Enorats]

But that sort of ejection is quite inefficient compared to simply leaving directly from low orbit. You always want to do burns as deep in a gravity well as possible, not on its outer edges.

As for fuel depots.. we've never even attempted orbital refueling so far as I know, and this station is not a fuel depot. It's a tiny habitat with a service module. Possibly eventually an airlock. Besides, if you want to refuel we're taking fuel from Earth. If you want to build a fuel depot you want to store it were you'll use it, and we're going to use it in LEO.. not lunar orbit. Why haul fuel all the way out there? If we were putting a permanent fuel refinery on the moon's surface and hauling it up into orbit.. then maybe. Even then it'd probably be better to haul it to a depot in LEO though.

As for experimentation, I don't think this station is being designed with much of that in mind. It's far smaller than the ISS and won't even be manned permentantly. Regardless, I think we have a decent understanding of the effects of space on human physiology. It does nothing good to us, and the only thing we can do is exercise our muscles and try to block as much radiation as possible. We don't need a hundred years of research to figure that out, and robotic probes can easily measure any environmental data we need to build a craft to survive that environment. At that point you just need to build the craft and test it.. not build an entire facility to test various components of your craft for a decade. That's like building an aircraft carrier to test the flightworthiness of a jet built for the marines. You can do one without the other.

[Xeorm]

Looking at what they say, they make some mention of lunar missions as well as Mars trips going off of the gateway. Giving some more reason for its existence. But largely, I think it's there because NASA doesn't care too much about delta V costs and the like. Efficiency is not their goal, safety and doing more space stuff is. The gateway would be a small time away from LEO, but after the magnetosphere, which is the most likely source of random problems they're going to run into. Making things a bit safer at the expense of fuel costs is, I'd think, worthwhile for an agency like theirs. Let private business experiment with cutting down costs. NASA can push the envelope in the meantime.

 

But, the big thing too would be the inevitability such a station provides. If you've got it, might as well use it right? Not to mention the extra publicity they might have. Makes perfect sense when you consider NASA as the agency it is and not a spreadsheet.

[Enorats]

It doesn't really add any element of safety though. Wouldn't it be better to send a transfer vehicle up to LEO (with an orion capsule, or take on up with crew as a second launch). It could spend awhile on a shakedown cruise in LEO with Earth mere minutes away if something goes wrong. If all goes well, then go to the moon with it to perform tests outside the magnetosphete. The Orion capsule would act as a lifeboat and could get them home even from lunar orbit.

At the end of the test, come back to LEO and drop the orion with crew back down. Send up fuel and another orion and you're good to go for Mars. Or, send a second generation transfer vehicle up already fueled. Now we don't even need orbital refueling.

Compare that to building a station over many years (requiring multiple launches), then sending a transfer vehicle to lunar orbit, testing it there (repeatedly bringing crew to and from lunar orbit.. or bringing the craft back to LEO between launches?), sending fuel to lunar orbit to refuel there, leaving from an inefficient location, and returning to someplace that isn't actually your final destination to park your spacecraft you potentially want to reuse outside of the protection of the Earth's magnetosphere.. in all that radiation that can't possibly be beneficial. Or not, they could bring it back to LEO at the end after the lunar station has "facilitated its return". Which begs the question, why was the station even necessary?

As for publicity.. It'll all be bad. Any layman will immediately think, isn't that what the ISS is for?! Why did they build that and just abandon it to immediately go build another one? They're looking to build this new station right about the time the ISS is decommisioned, so the headlines won't be pretty. They'll quite rightfully think it's just another big project without any clearly defined mission. As much as I love space exploration, NASA tends to be forced (by Congress or their own management) into very awkward projects with no real purpose or goal. This seems to be another of those unfortunately.

[Nibb31]

The point of the DSH is to provide a destination for Orion. Orion was designed for cislunar space and because there is no lander, the DSH is only place where Orion can reasonably go. Orion is never going to Mars.

In any Mars expedition plan, the MTV is assembled at the DSH (the DSH might even become the hab module for an MTV). On its return trip from Mars, the MTV inserts itself into EML-2 and the Orion ferries people back and forth.

[kerbiloid]

https://falsesteps.wordpress.com/2012/07/21/manned-venus-flyby/

Spoiler

 

Edited March 30, 2017 by kerbiloid

[Nibb31]

That's the old wet-tank Apollo Venus flyby vehicle. It has nothing to do with DSH. What's your point ?

[kerbiloid]

I have strange feeling of similarity.

[Nibb31]

There's nothing similar. The AAP Venus flyby vehicle was a wet-tank S-IVB hab with an Apollo docked to it. The crew was supposed to dock to the S-IVB, burn into the flyby trajectory, then purge the tanks and setup the hab during the flight.

The DSH is an EML-2 station based on ISS modules, with an optional SEP tug to take it to Mars. The Orion is going nowhere.

Edited March 30, 2017 by Nibb31

[YNM]

A plan is a plan - even an almost finished structure could become the biggest, worst rubbish if the interest has stopped.

I don't care how humanity will make it there - I only care if we actually are going to do it !

[Enorats]

Guessing Nibb is right, this seems like mostly make-work for Orion and SLS.

[JayPee]

Welp.

I think the best takeaway I'm getting here is that NASA isn't going to be able to do anything 'cool/worthwile/useful/purposeful/whatever' unless the US .gov is willing to invest a LOT more money.

But that, respected colleagues, is a matter of politics...

[Benjamin Kerman]

Anyone here read "The Case For Mars"?

[Mitchz95]

14 hours ago, Enorats said:

But that sort of ejection is quite inefficient compared to simply leaving directly from low orbit. You always want to do burns as deep in a gravity well as possible, not on its outer edges.

Burn to escape the moon and drop your perigee as low as possible. Then when you hit perigee, burn prograde and you'll already be going at close to escape velocity. Assuming you topped off your tanks at the moon, there would be a delta-v improvement over burning to escape from LEO.

[Enorats]

29 minutes ago, JayPee said:

Welp.

I think the best takeaway I'm getting here is that NASA isn't going to be able to do anything 'cool/worthwile/useful/purposeful/whatever' unless the US .gov is willing to invest a LOT more money.

But that, respected colleagues, is a matter of politics...

I'm reading a book called "The Plundering of NASA" at the moment that argued that really isn't the case. The way NASA is legally required to handle contracts isn't exactly conducive to recieving finished products in working order in a reasonable timeframe, let alone under budget. The Ares-1X launch alone cost more than NASA paid for the first three falcon 9 flights, and the whole upper half of that rocket was more or less fake.

6 minutes ago, Mitchz95 said:

Burn to escape the moon and drop your perigee as low as possible. Then when you hit perigee, burn prograde and you'll already be going at close to escape velocity. Assuming you topped off your tanks at the moon, there would be a delta-v improvement over burning to escape from LEO.

Even if that is true you're still building a station in lunar orbit, a fuel depot, taking your ship to lunar orbit, taking fuel to lunar orbit, and taking your ship back out of lunar orbit. Even if that final step costs slightly less than burning from LEO you've overcomplicated the process to the point that you could have done the mission a half dozen times over with less effort.

[Nibb31]

13 hours ago, Benjamin Kerman said:

Anyone here read "The Case For Mars"?

Yes, and it's a load of rubbish.

12 hours ago, Enorats said:

Even if that is true you're still building a station in lunar orbit, a fuel depot, taking your ship to lunar orbit, taking fuel to lunar orbit, and taking your ship back out of lunar orbit. Even if that final step costs slightly less than burning from LEO you've overcomplicated the process to the point that you could have done the mission a half dozen times over with less effort.

Not if you want to come back. On the return trip of the journey, it's supposedly easier to insert your MTV into EML-2  or lunar DRO than into LEO. You RV at the gateway with an Orion and ferry your crew home.

[Benjamin Kerman]

@Nibb31 The whole thing might not be perfect, but he has several good points. 

1) It would be almost impossible to bring everything we need with us to Mars. If we did try to bring everything from Earth, it would require exponentially more launches and a much higher cost.

2) Building a lunar base is not a "simulation" for Mars, as they have almost nothing in common besides being a rocky sphere. 

3) Traditional plans cost many billions of dollars, which leads them to becoming unfunded by the government. A self-reliant single/double launch mission would cost at a maximum 10 million US dollars, and as low as 3 million.

4) The technology used in The Case For Mars has already been proven, and all of the reactions and everything they plan to do has been around for many years. 

If you don't agree with these, please say why! I'm always open to changing my opinion, and all you got to do is talk. 

[DerekL1963]

31 minutes ago, Benjamin Kerman said:

The technology used in The Case For Mars has already been proven, and all of the reactions and everything they plan to do has been around for many years. 

Certainly the chemical reactions he plans of using have been around for years and have been well tested - at laboratory scale on a laboratory workbench.  The hard, and expensive, part however still lies in the future...  designing, building, and validating flight capable hardware.  And when you dig into the Case For Mars, you repeatedly find the same thing - "technology" used as a buzzword and a smokescreen to obscure the fact that almost everything the plan relies on doesn't actually exist as anything remotely resembling functional hardware.