Multiple Ares V launches for on-orbit/surface assembly

[dreada5]

Don't know if this has been discussed before, but does anyone know for a typical deep-space human mission whether NASA plans to carry out multiple CaLV (cargo launch vehicle) to assemble a large lunar/mars ships in orbit - before sending up the crew to dock?<br /><br />Will NASA even have multiple CaLV available to launch almost simultaneously for such an assembly task??<br /><br />How will Ares V launches compare in terms of cost with the current shuttle launches?<br /><br />Is it envisage that multiple Ares V launches will be used to deploy hardware to the lunar/martian surface for future base construction.<br /><br />I'm just thinking of the construction options that would become available with being able to launch multiple Ares V economically back to back and thus the ships/structures/bases etc that could be assembled.<br /><br />For example, a mars ship that has a habitable area almost as much as is available on the ISS, powerful nuclear engines and perhaps a single, heavy, thick-walled module that shields from cosmic radiation.

 

[henryhallam]

I'm pretty sure that any manned Mars mission will require multiple CaLV launches, though on-orbit assembly might be avoidable (see Mars Direct).

 

[lampblack]

Michael Griffin stated (I forget precisely where) that a Mars-bound spacecraft might be expected to mass 500 metric tons, give or take.<br /><br />Given that the heavy-lifter will haul 125 metric tons to orbit, that would seem to imply assembly of no fewer than four structures. (And who says former English majors can't do math?) <img src="/images/icons/wink.gif" /><br /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>

 

[qso1]

Currently, I have seen no NASA plans to build a large lunar vehicle in earth orbit and the mars plans so far are nebulous at best.<br /><br />Its highly unlikely that a large lunar ship would be assembled in orbit as there is actually no need for such a craft to support lunar missions. At least not until the lunar missions begin to emphasize longer stays.<br /><br />In that scenario, larger surface vehicles would be built.<br /><br />For mars, as Mattblack mentioned, the transit craft would probably weigh around 500 Mt. Launching the crafts components back to back would be difficult to do with only what are likely to be one or two pads for CaLV.<br /><br />Its not yet clear if the 2 complex 39 pads will be dedicated or interchageably used. Or if complex 39 pads will be used at all. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[dreada5]

Thanks for the answers guys.<br /><br />I envisioned in my mind the need for large ships not so much for lunar mission but more for mars missions. However I forgot about missions plans like Mars Direct, that do away with the need for one large vehicle by sending unmanned resources to Mars up front and then maybe only 2/3 CaLV launches for assemble a vessel that includes one of those transhab/mars habitable unit structures... they seems as though they would be provide more than adequate space for crews.<br /><br />As for lunar missions, I agree...the distance is so short that multiple CaLV launches would only be needed for base construction (not ship construction) and then there's no rush either.<br /><br />Thanks again

 

[dreada5]

I can see inflatable transhab/mars habitable units really becoming the future of crew accomodation for interplanetary missions.<br /><br />I guess the CaLV will be designed with a sufficient diameter nose cone to handle such inflatable modules.

 

[JonClarke]

The (very nebulous) Mars plans in the VSE are based on NASA Mars DRM 3.0. This required three Mars bound spacecraft, each consisting of two ~88-tonne elements assembled in LEO, the EDS and the payload. Total mass in LEO = 528 tonnes, close to what Griffin said.<br /><br />The assumptions of the DRM included a NTR stage for the EDS. The larger payload of the Ares 5 over the DRM's Magnum would mean that the option for a chemical EDS is now open, a wise move, given the political and technical uncertainties of NTR.<br /><br />This limited EOA approach is essentially the same as what is proposed for the return to the Moon - the docking of two spacecraft in LEO for earth departure. An additional launch for the CEV ferry would be required in the VSE Mars mission, replacing a shuttle launch for the DRM, this would be only for the crew ferrying spacecraft, who ride in either the Mars bound hab or the a dedicated transfer vehicle.<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>

 

[crix]

Wow, maybe we really aill go with a chemical, six-month trip to Mars. I've had it stuck in my head that we wouldn't actually try for the Mars mission until we had NTR and could do something more like a 2 or 3 month transit.<br />

 

[qso1]

IIRC, NTR was still quite limited in transit times. Somewhat less than six months but not three months. This mainly because even though NTR yeilds an ISP approaching 1,000, thats only about double what a chemical (LOX/LH2) would provide. And some of that ISP is lost on the reactors sheer weight.<br /><br />The disadvantage to chemical however is that LOX would be required and LOX is heavy. I had a book called the Mars operators manual which detailed a chemical craft design and the shuttle and Energia was to have carried it to LEO for assembly. Lots of flights I recall, but not the specific number.<br /><br />The three month transits come from work done on VASIMR which is a plasma propulsion system with a variable ISP which is something like 200,000 at the high end. The VASIMR program could have led to a system with somewhat better flexibility where trajectories are concerned and the three month transits.<br /><br />VASIMR was transferred sort of, to private industry last I heard. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[mattblack]

It's quite probable they wont use nuclear or nuclear-electric propulsion. And it depends on the exact nature of the designs. But assuming that Mars Semi-Direct (DRM-3) is the baseline architecture; just to send a crew to Mars on a Transfer vehicle with HAB/logistics Module, CEV, Earth Return Stage & Aeroshell -- this combined stack would mass about 150 tons. To send that to escape velocity with LOX/LH2 propulsion they'd need 2x EDS, burned in a Stage 1+2 configuration, which is about 200 tons of propellant.<br /><br />This gives an on-orbit mass before Trans-Mars Injection of 350 tons. Perhaps the 500 tons figure includes the Mars Landing/Ascent Vehicle and it's EDS which was sent on before? <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[barrykirk]

Well, it's about time that they gave it real name. It <br />needs that.<br /><br />I told my wife that the CaLV and the CLV now have the<br />Aries name and she looked at me and said, "the CaLV, <br />what's that?". I told her that it's the next generation<br />vehicle that I've been talking about all week.<br /><br />Without a real name nobody will remember it. Now it<br />has a name. Here's to Aries!!!

 

[JonClarke]

In practice, NTR ground test have never achieved Isps approaching 1000. The best performance was supposedly by some small Russian designs that were ~920, and NERVA was in the low 800's as I recall. They are much heavier than chemical engines. So the performance advantage for a NTR stage from the same starting orbit is about 150% of a chemical stage of the same mass. However safety conferns mean that NTRs (if they fly) will start from much higher orbits, I have seen a payload penalty of about 25%. There are also penalties for safe disposal orbits and post operation core cooling of ~5%. So the probable advantage of an NTR EDS is only 20% over what would be achieved for a chemical stage. The price of such an improvement is a much higher development cost and risk, let alone safety, security, environmental and political concerns. Hardly seems worth it IMHO, for a Mars mission.<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>

 

[qso1]

JonClarke:<br />In practice, NTR ground test have never achieved Isps approaching 1000...<br /><br />Me:<br />We really haven't had a lot of practice with NTR but, the lower, even a 950 ISP is not that much of an improvement IMO. I'd go with plasma if chemical proves to require a lot of LOX tank assembly flights. Assuming for a sec that at least two LOX tanks are required, and they are shuttle LOX tank sized. IIRC, the LOX tank in the shuttle full weighs 1.3 million lbs.<br /><br />In any case, once we finally start working on going to mars with humans, chemical will most likely win out over other propulsion choices. That is, if we go within the next three decades. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[gunsandrockets]

http://uplink.space.com/showflat.php?Cat=&Board=missions&Number=412125&page=&view=&sb=&o=&vc=1<br /><br />That link has a nice graphic from the ESAS report showing the Mars mission design. Three spacecraft using NTR propulsion would be sent from Earth to Mars. Each spacecraft would be assembled in Earth orbit by docking together the payloads of two CaLV launches. Two of the spacecraft launch towards Mars unmanned. The third manned spacecraft (named MTV for Manned Transfer Vehicle) before departure for Mars would be crewed by the launch of a CEV to rendezvous with the MTV in Earth orbit. Thus the NASA plan would use a total of six launches of the CaLV plus one launch of the CLV.

 

[qso1]

MTV, years ago I used the same acronym for a story about going to Mars. Only mine was "Mars Transit Vehicle" as it was specifically for going to mars and back. I later dropped the use of MTV because I wasn't sure if I could if the story had been published. This because of Music Television. But I was unable to publish it so now its a moot point. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[gunsandrockets]

" However I forgot about missions plans like Mars Direct, that do away with the need for one large vehicle by sending unmanned resources to Mars up front and then maybe only 2/3 CaLV launches for assemble a vessel that includes one of those transhab/mars habitable unit structures... they seems as though they would be provide more than adequate space for crews."<br /><br />The Zubrin plan for Mars Direct only takes a crew of four to Mars while the NASA plan takes a crew of six. If the NASA plan was scaled down than no doubt fewer of the Ares V cargo launches would be necessary. Plus it's important to remember that the Zubrin plan that uses only two cargo launch vehicles includes optimistic mass calculations and other fun things like no apparent means of launch escape for the crew (shades of the Space Shuttle!). <br /><br />

 

[CalliArcale]

FYI: the sub-discussion about NTR has been split off into its own thread: Nuclear Thermal Propulsion. Please go to that thread for further discussion on that topic. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[jtkirk1701]

how much dose it cost to do launches to earth orbit and launches to the moon? would it be cheaper to build a multitask vessel in space to use for the next 50 years or say 10 launches a year for the next 50 years??? maybe we need both???<br />

 

[qso1]

AFAIK, there is no really reliable method to determine cost of human space missions. Some general cost data can help get some understanding.<br /><br />Shuttle missions are estimated based on flight number. The lower that number, the higher the cost. The cost is currently around $500 million.<br /><br />Apollo missions to the moon were about the same...in 1970 dollars. But those 1970 dollars after adjusting for inflation put individual lunar missions at around $2.5 B dollars.<br /><br />The multitask vehicle already exists. Its called shuttle. And we simply do not have the technical mastery to build a multi task vehicle that is also inexpensive relatively speaking.<br /><br />The cost of human space flight is more about paying for technical expertise than actual hardware cost. For an LEO vehicle and a lunar vehicle, the personnel cost will be about the same so long as the personnel numbers are not significantly different between programs.<br /><br />It should also be noted that these costs are based on government run programs. This has resulted in what I call "The cost barrier". This barrier has stalled our human spaceflight progress beyond LEO for the past three decades.<br /><br />IMO, its going to take a major shift. One provided potentially by the emerging private industry efforts. P.E. in conjunction with NASA programs that will go where P.E. won't, is probably what its going to take to overcome the cost barrier and get humans on the moon and mars. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[josh_simonson]

About 4 billion/year is spent on the shuttle no matter how many times it flies. That's $666m if it flies 6x, $800m if it flies 5x, and $1b if it flies 4x.<br /><br />Last years RTF1 flight cost $12B since it was 1 flight in 3 years...

 

[john_316]

You mention NTR and VASMIR however but no mention is made of Gas Core Nuclear Propulsion which in the best case scenerio's still provide for less than 120 day transit times to Mars. I think there is a favorable study which specifies a 72 day best period of travel to Mars.<br /><br />I still do not believe even basic chemical means will give us less than 120 days travel time to mars.<br /><br />I do believe in a reusasable Mars Transit Vehicle. I have posted this before on my posts and even posted basic drawings of a MTV of different types.<br /><br />Nuclear electrical propulsion I still do not believe meets the time requirments. VASMIR? I am still out on it. I do not believe Ion propulsion should be used for the manned part of the mission.<br /><br />I however also support other propulsions methods for cargo and other supplies; i.e. ion, chemical, etc, etc.<br /><br /><br /><img src="/images/icons/smile.gif" /><br /><br /><br />Just another Nuclear Propulsion Supporter!!!!<br />

 

[publiusr]

We just need to support Ares V