Why does finishing the ISS require so many Shuttle Missions?

[dwightlooi]

I understand that a lot of the modules are still on the ground . In fact, some of them will never make it to the ISS. The number of shuttle missions required to assemble the station (depending on the degree of module omissions) range between 15 and 22. I am wondering is whether this is really necessary.<br /><br />Weight wise, a Delta IV (including Heavy) or an Atlas V rocket can handle anything the Shuttle can lift to LEO. There is NO ISS module in access of 26 tons. In fact even the biggest, heaviest modules like the multi-purpose laboratory module is just 19.3 tons with full equipment payload or 10 tons empty. Most other modules are lighter. Dimension wise, the 4.5 x 7 m modules will fit inside the 5 x 17m payload fairings of the EELVs. In fact a lot of the smaller modules may not even need a Delta IV heavy and can fly on a Delta IV (medium+) or Atlas V. Now, the payload interface will be different but I am sure that a suitable adapter can be fabricated for that purpose. Yes, there may be some technical issues and complications, but what happened to the "can do", "make it happen", attitude at NASA?<br /><br />Of course, the modules will not be able to assemble themselves. But this doesn't stop them from being launched to a parking spot next to the ISS. This way, one extended shuttle mission can assemble 3 or 4 modules already sitting next to the ISS. This should be able to cut down on the number of shuttle missions required to finish the station -- which both increases the likely hood that more of the modules will actually make it and decrease the number of shuttle flights.<br /><br />

 

[larper]

How do you go get the modules that are "parked" near the station? <div class="Discussion_UserSignature"> <p><strong><font color="#ff0000">Vote </font><font color="#3366ff">Libertarian</font></strong></p> </div>

 

[dwightlooi]

You send a shuttle up there and go grab them with the robotic arm?

 

[spacefire]

I'd suggest that the Shuttle is sent up unmanned with the modules, and the ISS crew can take over and do the assembly. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[radarredux]

> <i><font color="yellow">How do you go get the modules that are "parked" near the station?</font>/i><br /><br />Russia has proposed a middleman approach. Relatively dumb boosters deliver modules near the space station, then an intelligent space tug grapples them and puts it in position on the ISS. The space tug stays in orbit with ISS. This can be done for cargo or new components. It also opens the market to third party suppliers (e.g., SpaceX or Kistler) by reducing their requirements to service ISS.</i>

 

[larper]

Oh, I understand the need for a space tug to perform the task. It was a facetious question to dwight.<br /><br />It all sounds so easy in theory. Actually getting the stuff up there to perform all of these tasks is the hard part. That is why the station should have been lofted in much larger pieces on HLLVs, like SDLVs or something. Then you launch people with supplies on a few missions to put big pieces together, instead of on many missions to put the small pieces together.<br /><br />The cost of development and production of the HLLVs would have been more than paid for in the reduced number of shuttle assembly launches.<br /><br />So, you build 1 massive module that is basically Zarya, Zvezda, node1, Airlock, and Z1 truss all put together. Enough to be mannable and dockable with shuttle. That is one HLLV lauch.<br /><br />Next, you have the equivalent of Destiny, node2, hab module, P0 truss. That is the second HLLV. After one assembly mission, the station is ready for science and can hold 7 people.<br /><br />Third HLLV is the port wing. Fourth HLLV is the starboard wing. Core assembly is complete after 4 HLLVs and 3 assembly missions. Meanwhile the Russians have launched and docked 2 or 3 Soyuz emergency return vehicles. <div class="Discussion_UserSignature"> <p><strong><font color="#ff0000">Vote </font><font color="#3366ff">Libertarian</font></strong></p> </div>

 

[nacnud]

I think you might be able to do it in only 2 SDHLLV launches!<br /><br />The first takes up a station C giant tin can with minimal solar panels to keep the station alive waiting for the second launch.<br /><br />The second launch takes up the solar truss. The current one will mass 137ish tonnes when complete I'm sure that a single peace design could shave 20 tonnes off to fit on the proposed 120 tonne launcher. <br />

 

[vt_hokie]

There are 8 flights required to reach ISS "U.S. core complete". See http://spaceflight.nasa.gov/station/assembly/index.html<br /><br />There's no sense in adding Node 2 if you're not going to launch the European and Japanese lab modules. So, figure on three more flights for those. Maybe add a flight to launch the cupola, and you've got the space station more or less completed with a dozen flights.

 

[nacnud]

I think ESA and JAXA would linch NASA is they tried that one.

 

[larper]

I think you mean "12 more flights", not 12 in total. Total number of assembly flights was originally slated at around 30. Versus 2 or 3 for a HLLV launched station. <div class="Discussion_UserSignature"> <p><strong><font color="#ff0000">Vote </font><font color="#3366ff">Libertarian</font></strong></p> </div>

 

[chriscdc]

But that would annoy our international allies. I doubt that any of them would really give a dam though.<br /><br />Just imagine multiple tin cans in orbit. We could finally have one of those space stations from 2001.

 

[dwightlooi]

Ideally, a SHLV would have been developed in the 1980s as soon as it becomes crystal clear that the Shuttle is not and will never live up to it's initial promise of being a cheaper, safer way to LEO. But that didn't happen. We can go back and point fingers, but the point is that right now a SHLV does not exist and we have a half ass ISS in orbit. The EELVs however ARE up and running. They are capable of lifting the modules into orbit. And if you launch them at the rate of 3 to 4 a year (as opposed to 1 a year right now due to the collapse of the commercial launch market), they become very affordable $90 million per launch vehicles. In fact for most ISS modules, there will be enough mass and space left on the EELV to mount rudimentary Orbital maneuvering systems on the modules themselves. The second stage on the EELV will be able to get them within visual range of the ISS. They can tend conceivable be flown by remote control to hook up with the ISS's own robotic arm. You fly it like you fly a progress.<br /><br />Basically my point is not that we shouldn't send up anymore shuttles, but that we should do it only when it is absolutely necessary. This way we save money and we remove the need to fly shuttles at an unprecedented turn around rate just to finish the ISS. And, we stand a better chance of having a more complete ISS. Starting to develop a plan to do it this way also opens up the possibility of adding modules in the future when the shuttle has been relegated to museum displays.

 

[vogon13]

Orion could carry 20 complete space stations in 1 launch. And probably do it cheaper than a single shuttle launch.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[lunatio_gordin]

except, there's no way that they will let you make an orion in the next 100 years, so you can just give up that idea.

 

[paleo]

"But that would annoy our international allies. I doubt that any of them would really give a dam though'<br /><br /> Those are words of revelation. Exactly 'who' in those countries would be so annoyed? What are they going to do? Not invite Nasa's boss to a birthday party. The only ones annoyed will be those whose jobs and positions are at stake. 95% of the public has no clue about the ISS and half probably think it's like a big Tinker Toy that flits around the solar system.<br /><br /> ISS partners won't hardly give a hoot if the Shuttle is cancelled. It'll give then an excuse to get out of the ISS dead end. The Shuttle and ISS were (past tense) noble endevours. We learned a lot from the technology. The return on space dollars and effort is no longer warranted. Time to move on and all the 'partners' are aware of this as are many space keeners.

 

[dwightlooi]

Using a Nuclear fission rocket for orbital launches is insane. And Orion is not a nuclear heater rocket, it literally sets off nuclear bombs just aft of it's tail pipe. I can see such a design being used (eventually) in space for interplanetary flight -- once the tree hugger types get their mouths duck taped and NASA learns some pragmatism. But a ground launch and a flight through the atmosphere is complete insanity. Where are you going to launch it from? Florida? I bet you the citizens will grab their guns and rebel -- about 50% of american house holds have a firearm so you can't even put down the rebellion by force!

 

[paleo]

We don't need an Orion. We need a simple launch vehicle that comes with a long stick so the pilot can dip it into the tank to check the fuel level.<br /><br />K.I.S.S.

 

[JonClarke]

Those "ISS partners won't hardly give a hoot if the Shuttle is cancelled. It'll give then an excuse to get out of the ISS dead end." have sunk billions into the ISS with the expectation that they modulesl be flown by the US.<br /><br />They include the ESA laboratory module, the Japanese laboratory module. the Russian power module. If the US pulls out as you suggest then I hope those countiies and organisations sue the US for breach of contract and for every $$ they lose adjusted for full cost of capital investment lost. I would also hope they would never be so foolish as to work with the US in space again. Ever.<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>

 

[larper]

<blockquote><font class="small">In reply to:</font><hr /><p>Basically my point is not that we shouldn't send up anymore shuttles, but that we should do it only when it is absolutely necessary<p><hr /></p></p></blockquote><br />But using EELV won't work either. While technically, the shuttle COULD rendezvous with a parked module and drag it to the station, you will never see that happen. Just too dangerous, uses too much fuel, etc. Better to take the modules up with the construction crew.<br /><br />Now, I CAN point fingers and say we should have built an HLLV back then, because the same arguments that are being used now (there is no need of one, no market, etc) were used back then to trash Saturn V. So, everytime they use that excuse, I can point fingers and say, "But, wouldn't you have liked to have one 30 years ago?"<br /><br />One side of the argument says that there is no payloads on the books that require HLLV. The other side says that if you build it, they will find a use for it. History favors the latter.<br /> <div class="Discussion_UserSignature"> <p><strong><font color="#ff0000">Vote </font><font color="#3366ff">Libertarian</font></strong></p> </div>

 

[dwightlooi]

I think NASA should build a SHLV. It doesn't need to be economical or be operated frequently... One launch every two to three years at $1 billion a pop is fine. It is good to have it available. And $1 billion over 3 years is peanuts anyway.<br /><br />But I think it should not try to get equal a Saturn V. It should exceed it. It is not that hard really. A 10m diameter LH2/LOX main tank, 7 x RS-68 engines and 6 x Shuttle SRBs for lift off. That is 9.1 million kg of thrust at lift off with 77% of it being from the SRBs. 5 x RL-60 engines for the upper stage. That should lift a tad over 300 tons in a 10 x 40 m payload fairing to LEO. You can literally launch the ISS in one go. Three launches can assemble a 900 ton sapce craft for a Mars mission or a moon base. It's not that hard really.

 

[syndroma]

Without power and thermal control the modules will survive just couple of hours in space. And space tug needs time to be actually built.

 

[nacnud]

Something like spacehabs Apex might do the trick.

 

[gofer]

<blockquote><font class="small">In reply to:</font><hr /><p>I think NASA should build a SHLV. It doesn't need to be economical or be operated frequently... One launch every two to three years at $1 billion a pop is fine. It is good to have it available. And $1 billion over 3 years is peanuts anyway. <p><hr /></p></p></blockquote><br /><br />Unfortunately, it doesn't work that way. In-between the "pops" NASA's paying for the infrastructure upkeep, salaries to the large personnel, mostly idle factory lines, etc... ([edit] reminds you of the shuttle yet?) No private enterprise would stand for this kind of operation. According to asronautix.com when these "sunk" costs are factored in each Satrun-5 launch cost 2.4 billion dollars (in 2004 dollars)! No way in hell NASA could sustain this for 30 years. Anyway, "HLV" is a relative term, I consider 25 tonne to a LEO parking orbit "heavy lift", 15 medium, and 5 is "light". It's all in the context.<br />

 

[gofer]

[qoute]One side of the argument says that there is no payloads on the books that require HLLV. The other side says that if you build it, they will find a use for it. History favors the latter. <p><hr /><br /><br />I don't think so. The last Saturn 5 launched a modified second stage/Skylab, the oncore to the program, so to speak... a "leftover". ([edit] well, and there was a purely political ASTP Apollo-Soyuz mission) Then, they threw it overboard. I have no doubt if it'd been sustainable and affordable they'd have kept it, never mind the politics. Obviously, "they" were at a loss as to what to launch with it... The smaller rockets go up with useful payloads to this day, though...</p>

 

[grooble]

"According to asronautix.com when these "sunk" costs are factored in each Satrun-5 launch cost 2.4 billion dollars (in 2004 dollars)! No way in hell NASA could sustain this for 30 years."<br /><br />But every launch would bring that dev-factored cost down.<br /><br />I still think there should be an inquiry over the shuttle scam. People got ripped off big time. They were talking $20m a flight and it's closer to half a billion right?<br /><br />If it'd had been $20m a flight then the shuttle program would have been absolutely spectacular.<br />