Use of Shuttle External Tank in orbit

[mlorrey]

Burn time is what is varied.

 

[qso1]

My understanding has been the foam on the ET is to keep the aluminum skin from forming condensation icing which falls off in chunks posing a threat to the orbiter. I do not recall ever seeing images of the Saturn V with any sort of foam on the S-II and S-IVB stages.<br /><br />Even painted white, the foam was noticeable on the shuttles first 2 flights. The saturn-V upper stages had "USA or United States" markings on them, the foam would have made this a difficult task to paint the markings on.<br /><br />Was the foam sprayed directly onto the LH-2 tank before installation inside the stage? That is, foam that would be unseen from the outside. The boiloff problem is managed by an umbilical connected to the ET and a swingarm connected to the Saturn-V upper stages. <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>

 

[qso1]

Shuttle guy:<br />The l. hydrogen tank must have the convex shape to take the launch loads.<br /><br />My response:<br />Agree with you but this still requires modifications, an interstage between the stage the ET would be mating to in this case. The more mods, especially major ones, the less practical going with an ET is. Especially an inline SDHLV ET.<br /><br />Consider that if you do not modify the top of the ET, your simply placing a full propellant tank in orbit. A waste of an LV. The original plan was placing the ET in orbit in conjunction with shuttle/shuttle "C" missions which kills 2 birds with 1 stone.<br /><br />Shuttle guy:<br />The difference is only a few hundred feet per sec. Even when we were doing the OMS-1 burn the MECO velocity was only about 200 ft. persec below orbital velocity. The way it is done now is to have a MECO velocity and velocity vector such that the ET enters in a remote place <br />in the Pacific. That velocity magnatue is only a few hundred ft. per sec below orbital velocity. <br /><br />My response:<br />Even with that, the ET would not stay in orbit for very long, maybe a few weeks, months at best. That may or may not be long enough to get the internal outfitting missions up. A stable orbit that would be needed for the ET would be similar to what the OMS does for the shuttle orbiter. An example being the ability to place a payload at ISS altitude. The ET would require OMS type thrusters to achieve a stable orbit.<br /><br />"Radiation sheilding would be required which would be one reason for removing the tank foam. " <br /><br />Why do you say this?<br /><br />My response:<br />Don't recall saying that but if I did, The shielding is required to protect the module if its to be a space station type module. I'm not 100% certain thats an absolute requirement but I'd say pretty close.<br /><br />Mcs seattle:<br />How is such a precise pre-OMS burn speed managed when the payload weight for the shuttle can vary so much? Are the SRB's loaded with essentially <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>

 

[qso1]

The tank skin was the stage skin. The tank was NOT inside of the stage skin. <br /><br />My response:<br />I did find technical data on the S-II foam insulation but it must have been sprayed much thinner than on shuttle to not be evident in close up shots. In any case, even with foam insulation, the main point of ET to orbit is that it makes no sense to design an HLV to be tailored to place wet or dry ETs into orbit for later use.<br /><br />Wet:<br />Because if wet, that propellant needs to be expended to allow work to take place inside the tank once on orbit. This would mean using the ET as a boost for a payload on top. That can be accomplished by a stage design fitting of a practical HLV. If it were to turn out a practical LV is sized to utilize a 154' second or third stage, then the idea has merit, at least economically.<br /><br />Dry:<br />This involves sending an ET to orbit empty which in turn makes the LV dedicated to a mission in which the ET is a payload but how economical? Especially if the actual payload is say half the size of an ET. In which case, a specially designed container may be more practical. <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>

 

[mlorrey]

Um, not really. Your payload would be equipment tightly packed in a launch shipping container: (i.e. useless by astronauts until set up in a working setting) structurally strong, but not pressurized. In orbit, crew would move equipment from the container into the ET, lay out all the wire harnesses, and hook things up. The shipping container could be kept for receiving future payloads, functioning as a vacuum 'work shack', deploying exterior equipment.<br /><br />I've added a graphic of my own preferred CLV, an 1.5STO with no SRBs. It drops all but one SSME at 70% of fuel burned, as a single recoverable pod. This puts enough payload in orbit beyond the ET to include large deployable solar panel pods on the sides, built in decking, and an airlock/interface module as well as plenty of equipment to install inside.

 

[scottb50]

Not withstanding the foam problems I would think the size of the ET would reduce the emergency response capability. The Hydrogen tank would make it harder to find refuge in an emergency if it was fifty feet to an escape access. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

No.<br /><br />The increased volume actually gives you more time to reach an exit, since the volume is a cubic measure and your route to the escape of the other tank is a linear measure. It will take a lot more time for the air to escape for a given puncture size with this large size tank, and with the amount of space, it should be easier to find and repair leaks with patches as well.<br /><br />For those under delusions of explosive decompression, I suggest you watch the "Mythbusters" show dealing with this topic.

 

[qso1]

I'm assuming that your drawing, the ET portion is the brown part.<br /><br />While I realize the your idea is workable and is a good idea, its the cost of the mods and LV to get it to LEO that make me wonder as to cost effectivity.<br /><br />Your mods are just the heavy mods I'm thinking would make it just as cost effective to do a whole new vehicle. The tightly shipped package may as well be the new vehicle outfitted as a lab. Its almost like having a MOL on top of Skylab. The LV to get that whole config to orbit would be enormous, at least Saturn V sized. A whole new vehicle could be sized to a smaller LV.<br /><br />The whole reason an ET to orbit scheme ever came up was because it appeared the shuttle itself would carry a slightly modified ET to LEO and the ET would then be available for outfitting by later missions.<br /><br />One proposal had an engine cluster at the base of the ET to boost the ET to a stable LEO.<br /><br />The fact non of this came about despite several proposals indicated to me that the cost was much more than what they expected. That is, the cost of sending payloads already checked out on the ground. An example being the utilization of a shuttle "C" type vehicle that can send a completed module to LEO with only minimal on orbit final prepping before use.<br /><br />I'd love to have seen an ET based manned craft but the ideas have been around for almost three decades and nobody seems any closer to implementing it than they did then. Thats not to say it cannot happen, maybe space tourism will finally make such a proposal more attractive.<br /><br />BTW, nice graphics, what do you use to produce them? <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>

 

[mlorrey]

My point is that you can build a CLV using the ET SSTO configuration and wind up with a huge space station in orbit as profit (this drawing includes the mating/docking/airlock because it is conceived as the first mission, later missions would have half the cargo space available for non-station related cargo (in the manned version) or 3/4 of the payload capacity in the unmannde cargo version.<br /><br />Moreover, I've designed a whole constellation of launch vehicles based on this core concept, which uses NO SRBs, and results in the most possible infrastructure in orbit. Here is a graphic that shows it, and a link to the larger version:<br /><br />MY Launcher Constellation

 

[scottb50]

The problem I see is that looking at your base vehicle you use a standard ET with three engines. If you use the STS as a starting point your ET would be 70,000 pounds, assuming newer technology and three SSME attached. With propellant you would mass roughly 1,600,000 pounds. The three SSME's provide 375,000 pounds of thrust or a total of 1,125,000 pounds of thrust. This might cause a lot of noise and commotion, but it certainly won't get you off the ground. <br /><br />Now your three booster design would mass 4,800,000 pounds with 3,375,000 pounds of thrust. It would not get off the ground even without a payload. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Firstly, the design uses 6 engines (which I believe is plainly stated in the graphic). Only three were depicted for viewing ease, since they tend to overlap. Read the text, pictures are only pictures.<br /><br />Secondly, the ET is not 70,000 lbs. You are using the weight of the original ET design, which was 76,000 lbs. The Light Weight Tank was 66,000 lbs. The Super Light Weight Tank, the current version, is 58,500 lbs. Try to pay attention. Using these numbers, and the proper number of engines, as specified, the thrust is more than sufficient, allowing a T/W of over 1.3.

 

[rocketman5000]

i think that the configuration with cargo shroud F might need to launched at sea. With a launch vehicle that large going to the moon would be a no brainer. I could build a one peice habitate with a TBM at one end and just burrow it underground to provide radiation sheilding.<br /><br />Isn't it fun to dream?

 

[scottb50]

Firstly I can't read text in the graphic. When I zoom in on it it is too blurred to read. When I figured weights I was using even less than 58,000 pounds for the ET the rest covers the added structure to support the engines and the engines themselves. <br /><br />So lets say your ET weighs 55,000 pounds ready to go and has six engines, where are you going to put the propellant? <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

I provided a link to the higher resolution version of the graphic, right above the image.<br /><br />SSME's are 7,000 lb each, times 6 is 42,000 lb. Calced AFAIKR 20,000 lb for thrust structure, lines, and avionics. Calculating that, and thrust from 6 engines gives a T/W of a bit over 1.3.

 

[mlorrey]

Note the vehicle next to Cargo Shroud D: a Moon Base Ship. The top capsule is the core, the tanks have hatchs built into each end, so after landing, the ship is disassembled entirely with the tanks turned into agriculture and workshop space for the base.<br /><br />Cargo Shroud E features space and cargo for the Mars Base Ship, which reaches Mars orbit, sets up a base on Phobos out of tanks, and uses the vehicle on top as a lander and fuel ferry to land on Mars, collect water and bring it up to Phobos to turn into rocket fuel. Mission returns to Earth with half of the original tanks and one of the two nukes, having left some of the tanks and a nuke on Phobos for the next mission to use.<br /><br />Shroud F will send a major base facility to Mars for landing and permanent habitation on the surface.<br /><br />Don't know as F would need sea launching, but it would certainly need a slightly bigger crawler.

 

[mlorrey]

What are the advantages of the new turbopumps?

 

[space_dreamer]

Mlorrey, I love the way you think!!!<br /><br />The Cargo Shrould F design is Awesome!<br /><br />If you have not thought of a name for it yet, can i suggest "The God Rocket"

 

[tomnackid]

"My point is that you can build a CLV using the ET SSTO configuration and wind up with a huge space station in orbit as profit."<br />-------------------------------------------------------------------------------------------<br />I think that may be a bit of an overstatement. You end up with a huge empty fuel tank in orbit with decks and airlocks installed, but no life support, no electronics or scientific gear, no water or foodstuffs, no furniture. This would all have to be brought up and installed. All of the same issues that sank the Atlas wet workshop concept, the Skylab wet workshop, and all of the previous Shuttle ET space station concepts. <br /><br />We have been leaving spent stages in orbit since the very beginning of the space age so getting big empty tanks into orbit doesn't seem to be a problem. KEEPING them in orbit and finding a cost effective way of using them DOES seem to be the big problem. It seems to me that until we need hundreds of people in orbit it will be cheaper and more efficient to launch fully outfitted stations on HLLVs. Of course when we do reach the point of wanting hundreds of people in orbit or on the moon or mars your booster concepts would I think prove highly effective. Until then the "Stick" and the HLLV seem more economical and easier to develop.<br /><br />ps: Very nice drawings.<br />pps: If the "Stick" is an example of corporate welfare for ATK then who would be building your ETs and SSMEs? Elves? Gnomes? <img src="/images/icons/wink.gif" />

 

[mlorrey]

Actually, tomnackid, the first launch would include the docking module, to which 5 more tanks could be attached. It also would include the power supply (those grey cowlings along the side are deployable solar panels). That means 5 more launches, carrying up all sorts of equipment each time. This 6 tank space station would serve as the core of what would become a classic ring station of tanks suspended from the core and rotating for artificial gravity.<br /><br />Each launch could carry up 1/4-1/2 its payload capacity in equipment for the station, and the rest in paying customer payloads (who may themeselves be leasing space on the station and want to send up equipment for their facilities there).<br /><br />The only sticking point in the whole plan is that 1 out of every six SSMEs winds up in orbit. I've got a few proposals for bringing them home: <br />a) MOOSE: in the 60's, a way was developed to allow an astronaut to escape a spacecraft and reenter. They would seal themselves and their spacesuit into a big bag, which would fill with expanding foam. A small kick motor would deorbit the astronaut, and the foam would serve as the reentry shield. The astronaut would use a single person parachute for landing. I propose a larger version of this to return SSMEs to earth.<br /><br />If Moose doesn't work out, then the Russian MAKS minishuttle might be adapted as the cargo and crew carrier for every other launch, and be capable of returning multiple engines at a time (2 SSME should fit the MAKS cargo bay).<br /><br />Once the ring station is built and artificial gravity is created, people can be permanently stationed in space, and we don't have to worry about having seat space to return every single person up there.<br /><br />Now, I'm not saying that each and every ET needs to be saved, but the materials should be recycled to other purposes in space. We spend a lot of money to put each and every pound in orbit, we should be adamant about keeping it there and reusing it as many wa

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>They are safer, easier to build and do not need as many post flight inspections. Safety was the driver for the development of these VERY expensive pumps.<p><hr /></p></p></blockquote><br /><br />I remember reading an article when the new Block II SSMEs first flew. If my memory is not being troublesome, it said that the Block IIs can actually ingest pretty sizeable debris and keep operating (in theory; obviously one would not want to put that to the test in an actual flight), and that if they threw a turbopump blade, the resulting shrapnel would be more confined and would be far less likely to take out a neighboring SSME. <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>

 

[mlorrey]

Ah, well, that is good info. I had expected to put shrapnel shields between engines. With the six engine arrangement, the entry level model could lose an engine shortly after launch, and a second engine by 30% fuel burn, and still reach orbit.

 

[rocketman5000]

Shuttle_guy would be the better person to ask I guess, but does anyone have information regarding the construction of the Turbopumps and other machinery. In specifics weither the construction and manufacturing techniques are more demanding than that of an IC engine? Would it require more human handling than automotive engines or would it be possible to mass produce on an assembly line. <br /><br />also mlorry if you are going to be reusing the engines, you might want to figure out a way to reduce the labor to refith the motor after each flight. In particular the repolishing of the combustion chambers and bell. I am not a metalurgist but there should be a good metal that would resist the effects of the high temperatures and could be suitable for lining the nozzle. I ran across an article once while reading up on NTR's but was never able to find it again. If anyone could supply a link??? Pleeeease?<br /><br />

 

[qso1]

Your constellation of ET based rocket designs are impressive to say the least. This is actually a method of using the ET thats well outside the envelope of how the idea originated. It falls along the lines of what I had mentioned earlier about tooling the ET production line towards production of rockets or payload shrouds that are ET based.<br /><br />The original idea was lofting the ET to orbit in conjunction with a space shuttle mission. The ET which normally separates at 16,500 mph could be boosted to LEO by rockets at the base of the ET, or by some other method while the shuttle performs its mission.<br /><br />A stable orbit would be required to allow time to send up outfitting flights.<br /><br />Your proposal resembles past proposals that where lunar/Mars missions are concerned, involve huge boosters (As well they would) but also involve huge costs. The technical merits of the idea really are not in question to me. Its cost. I've seen too many promising concepts go the way of the dodo bird due to costs.<br /><br />Of course, after visiting your website, I came away with the impression you are trying to actually build such vehicles and all I can say is, best of luck. Someone has to break the cost barrier. Thats what stands in the way of cheap access to space. Or as I say, less expensive access to space.<br /><br />BTW, what program are you using for the graphics or do you do them by hand? <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>

 

[qso1]

I tried the other link which takes me to your website but not to where the constellation graphic is. Do you have a direct link to that? <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>

 

[mlorrey]

http://www.lorrey.biz/images/ext_tank_ssto.jpg<br />Here is a link to the large version of the graphic.<br /><br />I use Corel Draw, v 6.0. It's an older version of Draw, but I haven't really seen enough in the newer versions to justify upgrading, given the expense. It gets the job done, though as you can see in the first graphic I posted, the large image of the Shroud A launcher, it screws up the color gradients when you try to export directly to gif format, even with an optimized pallette..<br /><br />The big advantage of using the ET/SSME Pod as a modular system for many sizes of launcher is that you mass produce the ET and SSME (and engine pod) at quantities that will actually provide significant economies of scale. You need to look at this sort of transportation like container trucking and shipping. Standardized sizes and mass modularization attains the lowest costs.