Mars Direct; are we now beating a dead horse?

Oldfart1939 · 2017-10-06 10:06:34

Given the recent press releases from NASA about the Deep Space Gateway cluster f**k, and Elon's latest visions of grandeur, I'm now questioning the future of the Zubrin Mars Direct architecture. Not that I want to see the concept wither away after Bob's spent nearly a lifetime and his professional career promoting same.

IMHO, Musk's latest vision has merit, but my guess is he may have bitten off more than he alone can chew. Maybe we in the Mars Society should galvanize our efforts towards putting a kibosh on NASA's latest go-nowhere wet dream? The moon again? OK, but not a space station in cislunar space; if we want the moon again, go to the moon. If we want Mars, go to Mars, and not some workfare Deep Space Gateway. Maybe Bridenstine can bring some sanity back to NASA instead of workfare programs for "favored contractors?"
Elon is a truly talented guy, but he's simply getting ahead of himself, in the scientific and engineering sense.

Aarrgghh!

SpaceNut · 2017-10-06 15:25:45

Cost of Nasa is to great, Space x is to grand so I am thinking that somewhere in between is the answer....of mars direct and the other end of the scale.....

He is doing the "field of dreams" in that you build it they will come approach to large volume of men and cargo to orbit and beyond....

louis · 2017-10-06 18:14:17

I can certainly appreciate your despair at NASA - they seem to have lost all sense of direction.

I am a Musk fan however. He does deliver. He doesn't always get it right, but it seems to be with the new BFR he has brilliantly brought everything together into one product - a bit like the Model T Ford but obviously in a more niche way as there aren't going to be millions of BFRs produced. It's a brilliant way to spread costs across several profit centres. I think the concept just shouts "Eureka!"

This is I think the real beginning of Mars colonisation. I can't prove it of course yet but I think so much seems to be in the right place - at least technologically.

So yes, although Zubrin will be honoured as a great visionary, I am not sure his vision is still relevant. I am personally giving up on my dreams of a small scale Mars settlement project. Such dreams seem pointless if we are now going to see two 150 tonne cargo ships land on Mars within a few years.

Oldfart1939 wrote:

Given the recent press releases from NASA about the Deep Space Gateway cluster f**k, and Elon's latest visions of grandeur, I'm now questioning the future of the Zubrin Mars Direct architecture. Not that I want to see the concept wither away after Bob's spent nearly a lifetime and his professional career promoting same.
IMHO, Musk's latest vision has merit, but my guess is he may have bitten off more than he alone can chew. Maybe we in the Mars Society should galvanize our efforts towards putting a kibosh on NASA's latest go-nowhere wet dream? The moon again? OK, but not a space station in cislunar space; if we want the moon again, go to the moon. If we want Mars, go to Mars, and not some workfare Deep Space Gateway. Maybe Bridenstine can bring some sanity back to NASA instead of workfare programs for "favored contractors?"
Elon is a truly talented guy, but he's simply getting ahead of himself, in the scientific and engineering sense.
Aarrgghh!

GW Johnson · 2017-10-07 08:47:34

The new appointee Bridenstine has a very clear preference for the moon, not Mars. That's been in the news. Add that to the contracts already given to "big space" (not Spacex or any other "new space" entities) for the Gateway space station in cislunar space (but not actually in lunar orbit).

Then add in all the scare literature over "radiation dangers" and "planetary protection" issues.

To that, further add in the desperately-resolute refusal to address artificial gravity to control microgravity diseases for missions longer than a year.

That sum adds up to: NASA has no intention of going to Mars in our lifetimes. Don't listen to what they say, look at what they actually do. Talk is cheap.

If anybody does go in our lifetimes, it will be either a private outfit like Musk, or else another country. The handwriting is on the wall, clear as a bell, and has been for a long time now.

GW

Last edited by GW Johnson (2017-10-07 08:49:26)

Oldfart1939 · 2017-10-07 13:03:46

Sadly, I'm in complete agreement with GW; that's why I started this thread in the first place. Over the years I have been a big NASA supporter, but what the agency needs now is a combination of enema to flush out all the crappy ideas, and a beheading of the top brass supportive of the workfare industry.

Oldfart1939 · 2017-10-07 13:38:08

Where do they get these "Deep Space Gateway" ideas? Where do they originate? As Bob Zubrin said at the conference, if all we can do with the SLS is build a Deep Space gateway with it--we wasted our tax dollars and should build a real heavy lift vehicle capable of achieving the desired goal--MARS!

By their actions ye shall know them....

RobS · 2017-10-07 15:10:07

The Deep Space Gateway idea works well if (1) you are using small expendable rockets and (2) need electric propulsion or lunar water for deep space exploration. If Musk builds the current plan of the BFR (and I hope he does) he will render the SLS an embarrassment and the Deep Space Gateway will be obsolete.

How long did it take him to launch a Falcon 9 from the first time it was proposed? 5 years? He's been working on the Raptor engine now for 2 years. He's been work on the carbon fiber fuel tank for over a year. His company knows how to build software and computers to control rockets. With a billion or 2 dollars--which he has--and 2 or 3 years, he can launch the first BFR. I suspect the first launch will be about 2020.

I also suspect the carbon fiber technology will need a lot of maturation and development, and Musk will face challenges with it. For all we know, a BFR could disintegrate during launch as a result. But he'll figure that out eventually.

louis · 2017-10-07 16:34:07

Quite. NASA has completely lost its way. I think part of it has to do with the way the scientists rather than the visionaries have got control of the agenda. Scientists can always think of interesting things to do, try out, test, visit...but there are so many of these things that you end up with a negotiation and a huge number of diffuse and unco-ordinated objectives emerge (compare and contrast with the laser focus on the Moon in the sixties). I have always been a firm believer that establishing a colony on Mars will actually further all the science that NASA wants to do much more effectively than throwing money at the individual objectives.

Oldfart1939 wrote:

Where do they get these "Deep Space Gateway" ideas? Where do they originate? As Bob Zubrin said at the conference, if all we can do with the SLS is build a Deep Space gateway with it--we wasted our tax dollars and should build a real heavy lift vehicle capable of achieving the desired goal--MARS!
By their actions ye shall know them....

SpaceNut · 2017-10-07 18:50:42

The deep space gateway is little more than a mini ISS for transport as a habitat for any journey long or short as modified for the term of use. As GW has indicated if this is a research pawn then where is the radiation, artificial gravity and more in its research pathway of use and experimentation.... Its none of this and as others have said its a workfare project to keep people employeed...
The fact that Nasa is allowing the old modules as a core developement platform with out expanding the diameter to 10 meters and allowing for radiation protection is just another disappointment in its self...

RobertDyck · 2017-10-07 20:13:52

Oldfart1939 wrote:

Where do they get these "Deep Space Gateway" ideas?

The "90 Day Report" included a rocket as large as a Saturn V (SLS), a redux of Apollo (Orion), a space station in Earth orbit (ISS), a permanent Moon base, mines to harvest lunar ores and smelt them for metal and oxygen, and lunar depot with tanks of LOX, tankers to carry lunar LOX back to Earth orbit, and a lunar LOX depot in Earth orbit.

To answer your question, the next thing in the "90 Day Report" was a second space station, a ship yard to build a giant ship for Mars. If they can't have all that, they see the next thing as the second space station. They built one, so now they know how to build it. And their workforce to build ISS is now idle, they need something to do. So they want to do that piece next.

When I say "they", I mean corporate executive of contractors. They appear to have bought off key NASA personnel, and key Congressmen.

Last edited by RobertDyck (2017-10-07 21:17:42)

Oldfart1939 · 2017-10-07 20:56:56

W/R to the Deep Space Gateway, I will again quote the fountainhead of all knowledge, Forrest Gump: "Stupid is as stupid does." The SLS was an enormous and expensive boondoggle, and now to make things worse, a space outpost designed by Josef Mengele for radiation experiments on humans.

I've essentially had it with NASA. Go Elon! Go Jeff Bezos!

kbd512 · 2017-10-08 11:37:11

The Deep Space Gateway (DSG) concept can and should be designed as a transport vehicle enabling inner solar system transits. It just needs a propulsion module to do that. I think Boeing's use of existing ISS hardware for deep space habitation is the right idea. This notion that we have to take off in a Saturn V class rocket and land the upper stage on Mars is crippling. There are too many divergent technical requirements to affordably do that.

The DSG needs to be a long duration habitat that provides the electrical power, food, water, radiation protection, artificial gravity, and life support systems redundancy required to assure that we get our people back after a mission. The DSG should be capable of being mated to a primary propulsion module.

A series of three of the node modules (one for surface habitation and two for transit habitation) can provide enough consumables for a crew of 4 people. A series of Falcon Heavy or BFR flights can provide the fuel for propulsion. Good / better / best is a matter of opinion. Right now we have nothing because we can't get anyone at NASA to simply "decide" to use the existing ISS hardware to the extent feasible, develop whatever we need that we don't have, and forego advanced propulsion systems until such time as those systems are ready for prime time.

An egregious amount of time and money has been wasted on these giant rocket concepts and have produced nothing but an endless series of redesigns that basically say "Well, it was a great concept, but it was so massive as to be completely cost-prohibitive for us to actually use." The original BFR was far too big. The new BFR is still larger than Saturn V. Only NASA's old contractors produced a Saturn V class rocket and that was with functionally unlimited funding. The Saturn V was a one-time event in human history where cost and complexity didn't matter because we had something to prove to an adversarial nation. It's time to move past Apollo Program era thinking so we can actually achieve something worthwhile.

Smaller heavy lift rockets like Falcon Heavy are affordable enough that NASA can spend their money on all the other development projects required to send people to the moon or Mars with a reasonably good chance of returning them in the same condition they were in when they left. Anything more ambitious than that will have to wait for better times. WaPo and other media outlets have already taken to the internet to poo-poo Mr. Musk's latest plan and tell us all how we have to fix all of our problems here on Earth before we think about space exploration and colonization. There's little public interest in space exploration and not enough funding for these giant rocket and capsule projects.

And yes, at this point I rate the exploration and colonization plans of Mr. Musk and Mr. Bezos above those of NASA, but neither of those two entrepreneurs have the private capital to execute their plans, absent heavy subsidization from our government. If our government wants to subsidize their exploration plans, I'm not opposed to that. Good luck getting Congress to front the public money.

Terraformer · 2017-10-08 13:13:35

They might front the money for a Lunar base, if it's cheap enough - possibly one making money off other things such as tourism. That, and other markets, could get us to a better space station/fuel depot. With the experience and infrastructure from those, maybe a Mars mission would come to the point where they can be offered seats for $1 billion each, with the implied threat it will be a Chinese or Russian person being the first on Mars if they don't pony up...

kbd512 · 2017-10-08 13:33:10

Terraformer,

There's just no economy of scale to be had until someone, presumably SpaceX or NASA, proves that we can go to Mars and come back. SpaceX doesn't have the capital required to address every aspect of a mission to Mars. Maybe they can help build a lunar base. A lunar base at least gives us experience operating a base on another planetary body. I'll take whatever we can get at this point that involves humans and other celestial bodies.

louis · 2017-10-08 14:04:29

Why do you say Space X haven't got the capital to establish humanity on Mars? How much capital do they need? Not all the costs of the BFR development will fall to the Mars mission - they will be shared with ISS supply, satellite launches, orbital tourism, lunar tourism and long range flight on Earth. Space X expect to earn a profit of $15-20 billion pa from its satellite launches by 2025. Maybe they are being too optimistic but there is a lot of money in the space business. I doubt the Mars mission will cost more than $10 billion. A lot of that could be covered through commercial sponsorship and sale of TV rights, plus sale of experiment space on the first mission. Space X has regular revenue as well which will allow them to borrow significant amounts.

kbd512 wrote:

Terraformer,
There's just no economy of scale to be had until someone, presumably SpaceX or NASA, proves that we can go to Mars and come back. SpaceX doesn't have the capital required to address every aspect of a mission to Mars. Maybe they can help build a lunar base. A lunar base at least gives us experience operating a base on another planetary body. I'll take whatever we can get at this point that involves humans and other celestial bodies.

Terraformer · 2017-10-08 14:12:19

Profit? Or gross revenue? For that to be only profit, there would have to be a massive expansion in space activity. If they managed to make a profit of $1000/kg launched - which would entail them to maintain their current competitive edge AND charge just below their competition to maximise revenue - they would be launching 20,000 tonnes into orbit every year. We're nowhere near that at the moment - 2014 saw less than 100 launch attempts, and those are not being launched on superheavy rockets.

kbd512 · 2017-10-08 16:52:39

Terraformer,

The capital available has to be a combination of profits from the company and investments from investors that understand and accept that it's a high-risk, low-reward (short term, potentially very high-reward long term) investment. If private companies manage to establish a space economy that can efficiently move people and cargo around the solar system, there will be an explosion of economic activities related to space travel and exploration. If EMDrive works, then that may very well be possible. Chemical propulsion and nuclear propulsion are both far too expensive. There may be some way to economically extract water or gases from celestial bodies for use as chemical propellants, but so far there is very little investment to that end and no working hardware to demonstrate the feasibility. Mr. Musk and Mr. Bezos have a very difficult up-hill-all-the-way battle to prove the feasibility of their transportation concepts. I don't want to discourage them, but they have first order technical and economic challenges to overcome. For the future of humanity, I wish them both good luck.

Oldfart1939 · 2017-10-08 17:00:13

One difference with Jeff Bezos and Elon Musk's companies; they are both privately held and are not subject to the regulations regarding stockholder minority rights. If Elon says "spend the money," there's nothing to stop it from being spent. Ditto with Blue Origin and Jeff Bezos. Two of the richest men in the world can do what NASA is afraid to even propose, much less do...

RobertDyck · 2017-10-08 21:07:03

kbd512 wrote:

The Deep Space Gateway (DSG) concept can and should be designed as a transport vehicle enabling inner solar system transits.

I disagree most strongly. The DSG is not configured as an interplanetary vehicle. It can't withstand the high-G acceleration of a chemical stage injecting it into a transfer trajectory. These light modules with weak connections points would break apart. Furthermore, it's not configured for artificial gravity. I agree that life support should be based on ISS, but using hulls from ISS is just wrong. And placing it between Earth and the Moon? The only reason for placing anything there is the only vehicle that could reach it is Orion launched on SLS. Dragon on Falcon 9 could not reach it. CST-100 Starliner on Altas V, Dream Chaser on Atlas V, or Russia Soyuz on a launch vehicle by the same name. None can reach it. As for cargo resupply, ISS currently receives Progress launched on Soyuz, Dragon v1 on Falcon 9, and Cygnus launch on either Antares or Atlas V. The purpose of DSG is to put it out of reach of anything, so Orion/SLS will have a monopoly.

One major problem with Orion that they don't want to talk about is the fact it's too small to be used without a Deep Space Habitat, and too large to be used with one. It's too expensive to build, and its large mass makes it too expensive to launch. It's not good for anything but lunar orbit; it's a single purpose spacecraft.

Last edited by RobertDyck (2017-10-09 09:42:12)

elderflower · 2017-10-09 04:41:52

Musk doesn't plan on keeping Dragon, anyway. BFR has no use for an intermediate platform. The Deep Space Habitat has no useful purpose apart from ensuring corporate cash flows!

RobertDyck · 2017-10-09 10:04:30

That assumes BFR will be built soon. I'm assuming it will take a lot longer. Falcon Heavy has taken longer, still hasn't launched. BFR is much bigger and more complex.

The point of my post was to criticize DSG. Plans by the Old Space are dumb and designed to fleece taxpayers of as much money as possible.

Last edited by RobertDyck (2017-10-09 10:06:18)

kbd512 · 2017-10-09 10:28:46

Rob,

Can you tell us what information you base your assertion that ISS modules can't withstand the acceleration load applied? The S-IVB upper stage produced a bit over .6g at engine cutoff. The acceleration load limit factors for the Node modules, in any axis, appear to be at least an order of magnitude above that figure. The node modules have secondary internal structure to increase the rigidity of the modules. Presumably, ISS laboratory modules can be reinforced with secondary internal structure. Those modules had to survive peak loads of 3g and constant loads greater than 1g just to make it to space in one piece.

Is there any reason why Falcon Heavy and Dragon can't reach something in CIS-lunar space? I'm not advocating for sending anything there, unless it's for a lunar mission, just to be clear. I'm also not advocating for using Orion and have stated numerous times that the program should be cancelled and the individual technologies incorporated into a deep space habitat module.

RobertDyck · 2017-10-09 11:26:01

Current proposal, July 10 of this year.
My assertion is any modules sticking out laterally will rip off during TMI. CBM is so weak that Shuttle could not dock with it, Dragon and Cygnus and HTV could not dock either. Shuttle docked with the APAS hatch, then used either the Shuttle or station arm to transfer a module or logistics carrier to a CBM hatch. APAS has shock absorbers to allow a 125 metric tonne Shuttle to dock with a 100 to 300 metric tonne station. CBM has no shock absorbers, but APAS has a 0.7 meter diameter round inside hatch, while CBM has a larger square hatch. An equipment rack fits through a CBM hatch, not APAS. I'll look up the lateral load limits later.

My assertion is acceleration of a TMI stage (as you posted, S-IVB for Apollo produced 0.6g acceleration) would rip off any module not configured axially. That means the logistics vehicle, airlock, and the new Russian spacecraft depicted in this image.

For ISS, NASA delivered an adapter for the APAS docking hatch, converting it to a "NASA Docking System" (NDS). This is similar to APAS, but designed for a lower mass spacecraft that would hit the latching mechanisms with less force (low impact). Presume Orion and the new Russian PTK would use NDS. However, images show DSG with an arm, which presumes other modules use CBM. The one hatch visible on this image is on the side of the labelled habitation module; that hatch is clearly CBM.

RobertDyck · 2017-10-09 11:55:31

S683–28943, REVISION E, INTERNATIONAL SPACE STATION
Page 12

TABLE III. Rigidized ACBM/PCBM Interface Loads (Limit)
On–Orbit (Radial Port): Axial (lb) 4,500, RSS Shear (lb) 5,900, RSS Bending (in-lb) 442,000, Torsion (in-lb) 500,000

Please pardon US units, this document is dated October 1998. When Shuttle delivered a multi-purpose logistics module to ISS, total of the hull plus payload mass was between 8,811kg and 12,748kg depending on mission. Using the lowest mass, that's 19,424.929921 pounds, round off to 19,425 pounds. With 0.6g acceleration that provides 11,655 pound shear force. The limit of a radial port CBM is 5,900 pound shear force. Without calculating the other forces involved (bending, torsion), that already exceeds the CBM limit.

kbd512 · 2017-10-09 12:35:52

Rob,

Thanks for the info.

Is there any reason why an axial configuration can't be used, even with artificial gravity?

Is there any reason why a descent / ascent vehicle can't dock with the transit vehicle in LMO?

Apart from the attachment points for other modules or propulsion stage(s), is any other internal or external structural reinforcement required?

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Mars Direct; are we now beating a dead horse?

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