Methane dropped from CEV

[scottb50]

bye bye Mars.....<br /><br />I think with the current mindset, except for most if not all of us here, its more true than I think you intended it to be. <div class="Discussion_UserSignature"> </div>

 

[barrykirk]

I thought part of the allure of methane was that Methane was discovered in the atmosphere of mars.

 

[vt_hokie]

I always thought that any talk of human missions to Mars was very premature anyway. It will take significant advances in component reliability, debris impact protection, and perhaps most of all, radiation shielding. The crew will have to be self sufficient to an unprecedented degree, as obviously there will be no Progress resupply flights. Nuclear propulsion may be required to make transit times tolerable. All of this would require funding at levels beyond what NASA is likely to see for the foreseeable future.

 

[mikejz]

We can go to Mars 2 ways. 1) Develop new technologies, etc. or 2) Decrease launch costs significantly and simply use bruit force.<br /><br />As a proud American I prefer the 2nd option.

 

[trailrider]

"How so? I was not aware that Lockheed has anything to do with the Shuttle RCS system."<br /><br />It was Martin-Marietta Space Systems Division that designed and built the Shuttle RCS tanks with the capillary collectors for both N2O4 and Hydrazine, for use in zero-g. The bubble point testing was a real chore. I was only involved peripherally in processing some Engineering Change Orders for the RCS Tanks program, as well as Caution & Warning and Pyro Initiator Controllers (PIC), working those when my immediate supervisor got overloaded. My primary assignment was on SRB Decelerator Subsystem (parachutes), i.e., he handled Tanks, PIC & C&W, while I took the 'chutes, so we were more co-workers than subordinate/supervisor. Later I transferred to SRB-DSS systems engineering. But, yeah, MMC designed and built the RCS tanks.<br /><br />There are all sorts of pros and cons in each of these propellant combinations. Hypergolics are storable, but nasty to handle. But they require lighter systems due to not needing an ignition system, and are pretty dense.<br /><br />The thing to remember when determining the suitability of a combination is you have to consider bulk density x specific impulse, as well as storability.<br /><br />As far as flourine is concened...if you think N2O4 is corrosive...well, there's the old joke about the universal solvent (NOT water for the purpose of the joke)...problem is finding something to hold it! The only way they could use it for a first stage would be to park the launch personnel's cars in the next state. The windows would be completely etched opaque! <img src="/images/icons/rolleyes.gif" /><br /><br />Ad Luna! Ad Aries! Ad Astra!

 

[rubicondsrv]

" The only way they could use it for a first stage would be to park the launch personnel's cars in the next state. The windows would be completely etched opaque!"<br /> <br />not to mention the problem with the acid exuast attacking the pad structure itself. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

I'm all for bruit force.Hydrogen and Oxygen, put into orbit as water. <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

You are right of course. But the astronautix site in its biography of Mckay does specifically mention liver problems as cause of death and links it to the crash. I made the erroneous jump to hypergolics. This suggests there was another cause for the problems or the site is in error.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[henryhallam]

<font color="yellow">I'm all for bruit force.Hydrogen and Oxygen, put into orbit as water.</font><br />Why do people keep suggesting this? It's totally pointless. You need an incredible amount of energy to split water into H2 and O2, which means a very heavy power supply. Then you have to liquify them (more mass for the equipment) after which you STILL have to store them as cryogenics - so why not do that in the first place???

 

[spacefire]

I for one was always sure that the ESAS will never do anything for a manned Mars mission.<br />I'm being proved right evene earlier than I thought. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[spacefire]

It would be nice if we could capture asteroids and extract H2 from hydrocarbon compounds and O2 fro oxides, using an orbital nuclear power plant to supply the energy.<br />The fuels would be used for spacecraft that would sweep down from orbit and pick up payloads launched from Earth, in effect doing a multistage launch in reverse or something like the Kliper-Parom system.<br />Obviously you can't have nuclear-powered craft do that. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[krrr]

<font color="orange">I'm all for bruit force.Hydrogen and Oxygen, put into orbit as water.</font><br /><font color="yellow">Why do people keep suggesting this? It's totally pointless.</font><br /><br />Well for instance the Andrews CE&R report had that in their architecture, so it's not totally absurd.<br /><br />Since they were also using SEP tugs, they had large powerplants for electrolysis at their disposal.<br /><br />They were envisioning "water trading" as an opportunity for commercial launch suppliers. They also had lunar H2O ISRU in mind, if feasible. Water tanks also make a good radiation shield.

 

[JonClarke]

Lunar water, not terrestrial water. Unfortunately we don't know whether lunar water exists in useful quantities.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[krrr]

<font color="yellow">Lunar water, not terrestrial water.</font><br /><br />No no, the proposal was to launch water tanks into LEO, from where they would be transported (by SEP tugs) to an L1 station. There propellant would be manufactured by electrolyzing the water, using the SEP tug's power.<br /><br />H2O ISRU was only an afterthought in that architecture.

 

[darkenfast]

Reply to thread in general: I think it's already been mentioned somewhere here, but nasaspaceflight.com has a new member who worked on the ESAS report. He is taking questions, and has stated that he is against dropping methane and will be writing a paper about it (I'm paraphrasing from memory, but I think I have the essentials right).

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>You need an incredible amount of energy to split water into H2 and O2<p><hr /></p></p></blockquote><br />And energy, of course, is the most readily available and currently only in-situ space resource we can make use of, at least this side of the asteroid belt.<br />If one would ever want to mass-produce cheap rockets, water makes the perfect payload for such. it costs nothing, the payload canisters for it are the simplest imaginable, and its environmentally harmless, so launch failures can be tolerated.

 

[steve82]

I read somewhere the germans dabbled in H2O2 for submarine propulsion in WWII. At 95% purity the big problem was finding tanks that were pure enough not to have any catalytic elements present. they wound up using some kind of bladders.

 

[drwayne]

They came along too late in the way to have any impact, but they were quite effective, one of the first boats to have significant speed under water.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[drwayne]

Interesting reading:<br /><br />http://www.chinfo.navy.mil/navpalib/cno/n87/usw/issue_13/propulsion.htm <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[scottb50]

Water is much lighter than any other source of power and about as safe to work with as it gets. The Sun is available half the time in LEO or continuously in open Space, perfect for splitting water. Use the Hydrogen and Oxygen as either gasses or liquids to run fuel cells to provide power for everything else. <br /><br />Once in operation loses would be pretty low, so once launched and put into operation relatively little water taken to Space would be to support fixed facilities, most would supply propulsion and people which is the point of going to Space. People depend on water for survival, why not do as much as you can with something you have to have anyway?<br /><br /> <br /><br />I think it makes a lot more sense to launch water, simple, clean, infinitly re-usable. Look at the opportunities for small time launch companies. Small cheap re-usable rockets on a small scale, launch a few hundred pounds of water, cargo or people. Increase the scale and launch bigger loads, cheaper, theoretically. <br /><br />I would think, in LEO, open Space, even your house, gasses would work just fine. On the moon and Mars you would need cryogenics for backup, but if the same systems are used in LEO to provide propellants for Vehicles it become simpler.<br /><br />Finding water would be a plus but I think it will be a long time before we could tap an extraterrestrial source of water, methane or Oxygen. The one thing overlooked in Zubrins Mars plans is to convert the Martian atmosphere to methane requires adding the Hydrogen, which you have to bring with you. With my understanding that would take a lot of equipment, as well as power, to facilitate the reaction store and liquify the products ect. <br /><br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[john_316]

The US Navy also currently uses another propellent for the Mk48 ADCAP and MK 46 Torpedoes and that propellant is a monopropellant known as Otto Fuel II.<br /><br />Very deadly to work with if it catches on fire and someone breathes any of the fumes. Insta-death! (Hydrogen Cyanide Gas).<br /><br /><img src="/images/icons/smile.gif" /><br />

 

[JonClarke]

Actually, the Walther-powered U boat was quite lethal. They were hydrodynamically unstable at speed and plagued by fires and explosions. They were never operational. A few were taken into service post WW II by various countries and had dismal safety records. The Soviet and Bristih navy built a few of their own Walther cycle boasts, but these again did not reach operational status.<br /><br />The very advanced conventional type XXI U-boats reached operational status but did so too late to see service. They were the ancestor of the next 20 years o convention submarine design and some enjoyed long post war careers in other navies.<br /><br />The similar but smaller type XXIII did become operational and sank several ships in the closing stages of the war, without loss to themselves. <br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[darkenfast]

Just a trivial (and somewhat off-topic) point: the Type XXI subs did not operate in other nation's navies except as briefly used testbeds. The Soviets did use the design as a springboard for many classes of their own (the early version of the Whikey-class looks very much like a Type XXI). The U.S. and U.K. also used some of the ideas.

 

[john_316]

The US used the snorkeling system of the type XXI in the Darter class and it semi followed in the Blueback and Finback. <br /><br />That reminds me if the US wished to build them we could still build Diesel Submarines and more of them but for us the cost outweight the usibilty and survivabilty. <br /><br />I however do believe we owe Tiawan 8 diesel submarines, not to get off track here. <br /><br />The question comes to mind is the future CEV going to use methane or have they assumed the CEV will not touch down on Mars so why bother?<br /><br />I mean my point is that the CEV will just be a crew transport to the moon and ISS and the one going to Mars actually be larger and more robust like say just a MTV/CEV bound together as one. <br /><br />I just think the CEV is for that purpose and CEV-2 will be the Mars vehicle which will be a highly 100% different vehicle uprated from the basic CEV capsule.<br /><br />I still don't think methane will be used in it either. <br /><br />Why should it be if you already have systems in place that can do the job right?<br /><br /><br />

 

[JonClarke]

We are well and truly off topic <img src="/images/icons/smile.gif" /><br /><br /> Uboat.net lists the post war service histories of the type XXI’s<br /><br /> Those in British and US service had limited lives<br /><br /> <br /><br />U2513 served 3 years with the US navy<br /><br /> U3008 served 2 years with the US navy from 1946<br /><br /> U3017 served 4 years from 1945 with the Royal Navy as N41<br /><br />Those with the Russians lasted longer:<br /><br />U 2529 served 9 years from 1946 with Soviet navy as B28<br /><br />U 3035 served 9 years from 1946 with Soviet navy as B29 from 1946<br /> <br />U 3041 served 9 years from 1946 with Soviet navy as B30 and then PZS-35 from 1946<br /><br />Two however had quite exceptional post war histories as platforms for submarine R&Ds:<br /><br />U2518 served 18 years from 1946 in the French navy as Roland Morillot<br /><br />U2540 served 23 years with the Bundesmarine from 1957 (after 12 years on the sea bed post WW2!) as Wilhelm Bauer<br /><br />The Wilhelm Bauer has been deservedly preserved as a museum.<br /><br />Back to methane!<br /><br /><br />Jon<br /> <br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>