New mobile launcher for ARES I?

[holmec]

NASA Article<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>WASHINGTON - NASA has issued a request for proposals for Ares I mobile launcher construction. Ares I is the rocket that will transport the Orion crew exploration vehicle and its crew and cargo to low Earth orbit. The mobile launcher proposals are due to NASA's Kennedy Space Center in Florida on Sept. 6, 2007.<p><hr /></p></p></blockquote><br /><br />Why not use the old ones, I wonder? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[PistolPete]

The ESAS report recomended modifying three Shuttle MLPs for Ares I and building two new ones for Ares V. Perhaps the contract is for modifying a Shuttle MLP. <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>

 

[jimfromnsf]

As it has been discussed on other sites. It needs an umbilical tower. The "empty" Ares I is heavier than Saturn V empty. The combined MLP, UT and Ares I is too heavy for the crawlers. So a new one is needed. The Ares V will use modified shuttle MLP's but by that time new crawlers will be procured

 

[radarredux]

> <i><font color="yellow">The "empty" Ares I is heavier than Saturn V empty. The combined MLP, UT and Ares I is too heavy for the crawlers.</font>/i><br /><br />So Ares I, when moving to the launching pad, will be heavier than the Saturn V was? That's almost too funny.<br /><br />How does the weight of the STS compare to Ares and Saturn V when it is being rolled out to the pad?</i>

 

[comga]

In reply to:<br /><br /> Why not use the old ones, I wonder?<br /><br /><br />The "old ones" were designed for a 100 km lifetime IIRC, and they have logged thousands. They are based on archaic earth moving equipment and parts are no longer available.<br /><br />It would be interesting to know why we don't switch to rails, like most everyone else. Perhaps a pair of parallel standard gauge tracks. Railroads carry enormous loads, and you could always buy new engines for a modular system.

 

[ambrous]

The crawlers have supported : transport and check out of a dummy Saturn V, 13 Saturn V launches, 4 Saturn 1B launches and ~118? Shuttles.<br />All Saturn 1's and several Saturn 1B's were launched from complex 34 and 37 and were erected on the pad.

 

[MeteorWayne]

On the other hand a number of shuttles have made more than one trip to the pad (STS-117 comes to mind <img src="/images/icons/smile.gif" /> ) <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[comga]

Good point about climbing up to the launch pad. Its funny that the launchers have to climb a hill in Florida but roll horizontally in Kazakhstan!<br /><br />

 

[holmec]

I thought it was the soil itself. Using a tracked vehicle you can maintain the "road" easier without the pesky train tracks in the way, plus other vehicles can use the road as well. <br /><br />Train track system have trouble with steep climbs, like found in the Alps in Europe. But there are even trains in the Alps. So I doubt its an issue of grade. I think it also might have to do with that you have a vertical vehicle and it needs a wide base and train tracks don't fit with wide bases as well as tracked vehicles. <br /><br />Found a page with pics on the Ares I mobile launch platform <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[qso1]

RadarRedux:<br />So Ares I, when moving to the launching pad, will be heavier than the Saturn V was? That's almost too funny.<br /><br />Me:<br />Funny but quite possibly true. The Saturns were rolled out empty, as in no propellants. Otherwise, the Saturn-V would weigh in at 3,000 tons. The Aries 1 consists of a prepacked SRB first stage which loaded will weigh in at around 500 tons. An empty Saturn-V will weigh in at significantly less than 500 tons. <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>

 

[vulture2]

The Ares I launcher will have the service tower on the mobile pad, like the Saturn.<br />http://www.geocities.com/launchreport/ares1.html<br />There will be several umbilicals on booms that will pivot upward at T-0 (rather than swinging laterally, as they did with Saturn and do with the shuttle), and probably, to keep the tall rocket from bending excessively in the wind, a U-shaped sway damper that will drop away at T-0.<br /><br />Regarding the crawler, the main advantage of tracked vehicles is their ability to move over unprepared ground, not relevant at KSC because the crawlers move only on a prepared roadway. In fact, the crawlerway had to be artificially constructed; built up with about 2m of river rocks. Every few years the stones become crushed to the point where they can no longer slide around to spread the load, and have to be dug out and replaced. Florida has no rocks at all, so the materials have to be imported. Whenever a roll-out is due, the crawlerway has to be groomed.<br /><br />The crawlers are an astounding achievement, but to my knowledge the concept was an on-the-spot decision taken only because it seemed the fastest way to get the job done forty years ago, when maintenance and operating costs were almost irrelevant. Someone decided that the chassis of a strip mining shovel had the required load capacity and required relatively minor changes. I am not aware of any trade study.<br /><br />Although rails would have required a longer ramp at the pad, in the long run they would have saved a lot of money. So far as I know, rails are used for virtually all mobile service towers and mobile launch platforms around the world, other than the ones at LC-39, and require very little maintenance compared to the crawlers and crawlerway. An ordinary railroad car can easily weigh 100 tons, and locomotives more than 200 tons, With the typical two sets of rails used for a mobile service tower, t

 

[jimfromnsf]

"Although rails would have required a longer ramp at the pad, in the long run they would have saved a lot of money. So far as I know, rails are used for virtually all mobile service towers and mobile launch platforms around the world, other than the ones at LC-39, and require very little maintenance compared to the crawlers and crawlerway."<br /><br />MST's only travel a few hundred feet. That is why rails are used.<br /><br />They wouldn't have saved money, saldom used rails need maintenance too.<br /><br />longer ramp? All the way to the VAB?<br /><br />Another issue would be the switching required

 

[holmec]

I'd think also rails would be suseptable to the humid ocean air and corrode. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[vulture2]

>>MST's only travel a few hundred feet. That is why rails are used. <br /><br />The length of the dual railroad trackway for the MLPs at CX 40-41 is almost exactly the same as the lengh of the shuttle crawlerways. There are over 200,000 miles of mainline railroad track in the US, so the length is not significant. Here's a pic of the Titan IV on its MLP with umbilical tower being towed by a pair of ordinary switcher engines. Not nearly as impressive as the crawler, but it doesn't have to be.<br /><br />http://www.patrick.af.mil/shared/media/photodb/photos/031008-F-0000S-005.jpg<br /><br />The key design constraint is not the length of the route, but the fact that the same route is used repeatedly. Treads are designed for crossing unprepared terrain, but used repeatedly on the same roadbed, they invariably tear it up. They do not intrinsically have the precision required for placing an MLP in position, so hydraulic support systems are needed. In contrast, rail systems can normally just be driven into position and locked in place.<br /><br /> />>They wouldn't have saved money, seldom used rails need maintenance too. <br /><br />What maintenance? With the exception of tracks laid over inadequate foundations subject to erosion, rail maintnance is generally proportional to useage, and even with conventional ballasting, a well built track will require maintenance only after 10-30 million tons of traffic. <br /><br /> />>longer ramp? All the way to the VAB?<br /><br />Because rails have extremely low rolling friction, the grade determines the power required. A couple of conventional engines could pull it up the existing grade, but simply doubling the length of the ramp would cut the power requirements in half at minimal cost. <br /><br /> />>Another issue would be the switching required<br /><br />The LC-40/41 MLP track has switches; they appear to be conventional, excep

 

[jimfromnsf]

Titan is not a valid example. The weights are no way near the one on CX-39 <br /><br />Also the turns around the VAB are too tight

 

[vulture2]

>>Titan is not a valid example. The weights are no way near the one on CX-39 <br /><br />One reason the weight is lower is that the crawler, which accounts for 40% of the total weight, isn't needed in a rail system. Nevertheless the mobile service tower at Complex 37 is almost exactly the weight of the entire MLP-Crawler complex and moves on four conventional rails. <br /><br /> />>Also the turns around the VAB are too tight<br /><br />The two bays at the back of the VAB have not been used for assembly since Apollo. The remaining turns are no tighter than those at CX-40/41. Obviously any rail system would be designed with a minimum turn radius compatible with the design of the rolling stock. <br /><br /> />>I'd think also rails would be suseptable to the humid ocean air and corrode. <br /><br />Rails are used for mobile service structures in most of the launch complexes at Cape Canaveral and even for the Rotating Service Structure at LC-39, not to mention the cars that haul the SRB segments and a rail line along the coast. In spite of the salt air, I am not aware that rail corrosion has been a significant problem. Forty year old abandoned rails such as the ones that remain from the Saturn I pads at LC-37 have obvious rust but even there it doesn't seem deep enough to have affected their strength. Obviously protective coatings are available if needed.

 

[jimfromnsf]

"The two bays at the back of the VAB have not been used for assembly since Apollo. "<br /><br />Not true. One has been converted into a hurricane safe haven for the shuttle (there was an MLP in there this year) and also they will be used for Ares<br /><br />Again, MST don't count due to the short length of movement and no turns.<br /><br />Wrong about 40/41 vs 39, 39 is much tighter in front<br /><br />MLP Crawler doesn't include the launch vehicle

 

[vulture2]

>>"The two bays at the back of the VAB have not been used for assembly since Apollo. "<br /><br /> />Not true. One has been converted into a hurricane safe haven for the shuttle (there was an MLP in there this year) and also they will be used for Ares <br /><br />What I said was perfectly true. The bays have not been used for assembly since Apollo. You made a different point which in no way contradicts it. The hurricane shelter is a recent idea to use an available resource in a rare contingency. It has never been used, and would be applicable only if all three MLPs have stacks on them. It was certainly never a program requirement. <br /><br /> />>Again, MST don't count due to the short length of movement and no turns. <br /><br />I cannot accept this assertion. Are you suggesting that nothing can be done that hasn't already been done in exactly the same way? The MST clearly demonstrates that a conventional rail system can carry 4500 tons on four rails and only four wheel trucks. Why would this be dependent on the length of the rails? As to curves, it's not rocket science. At worst the four trucks would have to have pivots, as they do on a conventional railcar.<br /><br /> />>Wrong about 40/41 vs 39, 39 is much tighter in front<br /><br />What curves are you referring to? With the exception of the route to the backside of the VAB, the Google Earth map doesn't show anywhere the crawlerway has a turn radius of less than about 1000 feet, essentially the same as the turn radius of the tracks to SLC 40 where they split off from the ones to SLC 41.<br /><br /> />>MLP Crawler doesn't include the launch vehicle<br /><br />The MST weighs 4500T. The total weight of the crawler, MLP and Shuttle together is about 8500T, of which the Crawler is about 3000T. A rail-mounted MLP would be considerably lighter since it would not need the crawler; the wheels and drive motors are an insignificant fraction of the weight of the MST. Even the retractable grass playing field at Card

 

[comga]

Thank you vulture2 and jimfromnsf for this spirited discussion of the potential for rail transport. There is a lot of knowledge and good reasoning in response to my simple question.

 

[jimfromnsf]

The backside has been "used", just not in a hurricane. There has been a stack on that side.<br /><br />The "turns" to the backside includes the MLP parking area.<br /><br />The crawler concept was designed for heavier Saturn V with LUT's and MSS and potential future requirements

 

[CalliArcale]

Yes, I've learned a lot from listening to the discussion. Thanks, guys!<br /><br />Just to throw something else in, I learned from reading "Moonport!" that a <i>third</i> option was considered besides rail (which they would've used had the crawlers not been suggested): barges. Seriously. They seriously considered the idea of running a canal through the VAB and up to the pad.<br /><br />In the end, I think it shows that there are lots of ways to skin this particular cat. Which one to use is probably dependent on the circumstances at the time, and not on any particular solution being intrinsically better. <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>

 

[darkenfast]

While I don't think that it's worth changing at this point, the fact that the Soviet N-1 moon rocket was rolled to the pad on rails, shows that the method can be used for very large rockets. I think there were some issues with the Cape geology that made rails an inferior choice at the time. Anyway, I think we can all agree that the crawlers have the crawlers have worked well.