ARES LITE

[dwightlooi]

<p>Perhaps... just perhaps... NASA should build a much smaller version of the ARES I. Something intended to be responsive rather than heavy lift. The concept remains the same, an SRB with a LH2/LOX Upper Stage. But much smaller. Instead of a 20 ton CEV, it'll carry just a minimalist 4 ton capsule capable of transfering three astronauts with no supplies or small quanities of cargo and no humans to and from orbit with a 48 hour endurance in space.</p><p>Instead of a 5 segment SRB, it'll use a really short 1 segment SRB. Instead of a 125 ton upper stage, it'll use a 25 ton Centaur upper stage with a single RL10 engine. On top of the stack is a 4 ton class capsule. The upper stage itself acts as the orbital maneuver vehicle and the capsule is simply that, a 3 man re-entry capsule. 4-tons by the way is the same weight class as the Gemini capsules and Service modules combined.</p><p>Simple calcualtions indicate that a single SRB segment and a 25ton Centaur upper stage will put 4.5 tons into LEO. The lift off mass will be in the order of 180 tons; 150 of that the SRB, 25 the upper stage and 4 the capsule. The Solid booster will take the vehicle to about Mach 9+, the upper stage will take it the rest of the way to orbital velocities. </p><p> <img src="http://sitelife.space.com/ver1.0/Content/images/store/1/3/81f7f3e8-8d98-4a30-8346-7dd76cdc6754.Medium.jpg" alt="" /><br />&nbsp;</p><p>&nbsp;</p>

 

[kyle_baron]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Perhaps... just perhaps... NASA should build a much smaller version of the ARES I. Something intended to be responsive rather than heavy lift. The concept remains the same, an SRB with a LH2/LOX Upper Stage. But much smaller. Instead of a 20 ton CEV, it'll carry just a minimalist 4 ton capsule capable of transfering three astronauts with no supplies or small quanities of cargo and no humans to and from orbit with a 48 hour endurance in space.Instead of a 5 segment SRB, it'll use a really short 1 segment SRB. Instead of a 125 ton upper stage, it'll use a 25 ton Centaur upper stage with a single RL10 engine. On top of the stack is a 4 ton class capsule. The upper stage itself acts as the orbital maneuver vehicle and the capsule is simply that, a 3 man re-entry capsule. 4-tons by the way is the same weight class as the Gemini capsules and Service modules combined.Simple calcualtions indicate that a single SRB segment and a 25ton Centaur upper stage will put 4.5 tons into LEO. The lift off mass will be in the order of 180 tons; 150 of that the SRB, 25 the upper stage and 4 the capsule. The Solid booster will take the vehicle to about Mach 9+, the upper stage will take it the rest of the way to orbital velocities. &nbsp;&nbsp; <br />Posted by dwightlooi</DIV></p><p>I think it looks cute.&nbsp; <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-wink.gif" border="0" alt="Wink" title="Wink" /><br /></p> <div class="Discussion_UserSignature"> <p><font size="4"><strong></strong></font></p> </div>

 

[Zipi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I think it looks cute.&nbsp; <br />Posted by kyle_baron</DIV><br /><br />A little offtopic, but can't help thinking of Mini-Me after seeing the picture of Ares Lite: http://en.wikipedia.org/wiki/Mini-Me</p><p>But still, don't get me wrong I'd like to see ideas like this presented and some professionals judging its viability. For space technology intrested person like me these kind of things are at least very entertaining and educative. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-smile.gif" border="0" alt="Smile" title="Smile" /></p> <div class="Discussion_UserSignature"> </div>

 

[Bytor_YYZ]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Perhaps... just perhaps... NASA should build a much smaller version of the ARES I. Something intended to be responsive rather than heavy lift. The concept remains the same, an SRB with a LH2/LOX Upper Stage. But much smaller. Instead of a 20 ton CEV, it'll carry just a minimalist 4 ton capsule capable of transfering three astronauts with no supplies or small quanities of cargo and no humans to and from orbit with a 48 hour endurance in space.Instead of a 5 segment SRB, it'll use a really short 1 segment SRB. Instead of a 125 ton upper stage, it'll use a 25 ton Centaur upper stage with a single RL10 engine. On top of the stack is a 4 ton class capsule. The upper stage itself acts as the orbital maneuver vehicle and the capsule is simply that, a 3 man re-entry capsule. 4-tons by the way is the same weight class as the Gemini capsules and Service modules combined.Simple calcualtions indicate that a single SRB segment and a 25ton Centaur upper stage will put 4.5 tons into LEO. The lift off mass will be in the order of 180 tons; 150 of that the SRB, 25 the upper stage and 4 the capsule. The Solid booster will take the vehicle to about Mach 9+, the upper stage will take it the rest of the way to orbital velocities. &nbsp;&nbsp; <br /> Posted by dwightlooi</DIV></p><p>&nbsp;</p><p>Why?&nbsp; what are the reasons for it.&nbsp; Also it wouldn't be " responsive".&nbsp; ALso 48 hrs is too short.</p>

 

[dwightlooi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;Why?&nbsp; what are the reasons for it.&nbsp; Also it wouldn't be " responsive".&nbsp; ALso 48 hrs is too short. <br /> Posted by Bytor_YYZ</DIV></p><p>(1) It is responsive because it is small. Part of the reason launches takes weeks to setup is the problem of integrating a large vehicle, having to roll it on a huge crawler to the pad, then having a to tend to a very fragile sky scrapper carrying a cryogenic explosive fill while it stands gingerly in the elements. A small vehicle like this can be SILOED. You build say half a dozen SILOS in the ground, drop six of these in them with the paylod adapter sticking above the ground. You put a roof on wheels over it. Integrate the payload where it is sheltered by wheel the payload up at ground level and you launch where it is sheltered. The rockets are ready to go except for the LH2 LOX fueling. So what you do is fuel them up and launch in situ. 8 hours from decision to lift off of a pre-integrated vehicle, 24 hours if you have to swap payloads. </p><p>&nbsp;(2) 48 hours is what's needed to get into space, dock with the ISS or a trans lunar vehicle or some other separately launched sustainance module. Basically, you get up there and either dock or come back down. </p>

 

[Bytor_YYZ]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>(</p><p>1.&nbsp; A small vehicle like this can be SILOED. You build say half a dozen SILOS in the ground, drop six of these in them with the paylod adapter sticking above the ground. You put a roof on wheels over it. Integrate the payload where it is sheltered by wheel the payload up at ground level and you launch where it is sheltered. The rockets are ready to go except for the LH2 LOX fueling. So what you do is fuel them up and launch in situ.</p><p>&nbsp;2.&nbsp; 8 hours from decision to lift off of a pre-integrated vehicle, 24 hours if you have to swap payloads. &nbsp;</p><p>&nbsp;</p><p>3.&nbsp; 48 hours is what's needed to get into space, dock with the ISS or a trans lunar vehicle or some other separately launched sustainance module. Basically, you get up there and either dock or come back down. <br /> Posted by dwightlooi</DIV></p><p>&nbsp;</p><p>Still not responsive or a viable option. </p><p>1.&nbsp; Still need a transporter and erector to get the hardware into the silo (this is no different than current towers at the cape). &nbsp; Building silos at the cape is not really viable due to water table.&nbsp; Also the silo is still going to need access platforms like the towers.&nbsp; The launch from the silo is going subject the upperstage and payload to acoustic environments that they aren't designed for.&nbsp; Also using a LH2 stage in an enclosed silo is insane </p><p>2.&nbsp; It takes days to switch payloads. </p><p>&nbsp;3. It takes longer to get to the ISS. &nbsp; </p><p> This concept has many flaws in it and shows a basic lack of knowledge of operations</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Perhaps... just perhaps... NASA should build a much smaller version of the ARES I. Something intended to be responsive rather than heavy lift. The concept remains the same, an SRB with a LH2/LOX Upper Stage. But much smaller. Instead of a 20 ton CEV, it'll carry just a minimalist 4 ton capsule capable of transfering three astronauts with no supplies or small quanities of cargo and no humans to and from orbit with a 48 hour endurance in space.Instead of a 5 segment SRB, it'll use a really short 1 segment SRB. Instead of a 125 ton upper stage, it'll use a 25 ton Centaur upper stage with a single RL10 engine. On top of the stack is a 4 ton class capsule. The upper stage itself acts as the orbital maneuver vehicle and the capsule is simply that, a 3 man re-entry capsule. 4-tons by the way is the same weight class as the Gemini capsules and Service modules combined.Simple calcualtions indicate that a single SRB segment and a 25ton Centaur upper stage will put 4.5 tons into LEO. The lift off mass will be in the order of 180 tons; 150 of that the SRB, 25 the upper stage and 4 the capsule. The Solid booster will take the vehicle to about Mach 9+, the upper stage will take it the rest of the way to orbital velocities. &nbsp;&nbsp; <br />Posted by dwightlooi</DIV></p><p>Let's see this simple calculation.<br /></p> <div class="Discussion_UserSignature"> </div>

 

[dwightlooi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Let's see this simple calculation. <br /> Posted by DrRocket</DIV></p><p>The Shuttle SRB has an Isp of 237 secs at sea level, 267 secs in vaccum. Let's take an average of 253 secs for our calculations. Let's assume a SRB mass of 145 tons with a propellant fraction of 0.85 (same as shuttle SRB). Let's assume that the Centaur Upper Stage has a mass of 25 ton, a fuel fraction of 0.90 and an Isp of 462 sec (RL10B-2).</p><p>With that we are pushing a payload of 4 tons. </p><p>&nbsp;</p><p>Gross Delta V at 1st stage burn out = 253 x LN [(145+25+4)/(145 x 0.15 + 25 + 4)] = 3062 m/s</p><p>Gross Delta V imparted by Centaur Upper Stage =&nbsp; 462 x LN [(25+4)/(25 x 0.10 + 4)] = 6771 m/s</p><p>Total gross Delta V = 3062 + 6771 =&nbsp; 9833 m/s</p><p>Applying a correction factor of 0.80 (based on the correction needed for the ARES I which has a similar profile...</p><p>Net Delta V =&nbsp; 7866 m/</p><p>This is sufficient for LEO. </p><p>&nbsp;&nbsp;</p>

 

[Bytor_YYZ]

<p>&nbsp;Let's assume a SRB mass of 145 tons with a propellant fraction of 0.85</p><p>&nbsp;</p><p>Bad assumption. It would be lower.&nbsp; The aft skirt with TVC and roll control systems and the fwd skirt with recovery system weight would be combined with only one segment vs four. &nbsp; </p>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The Shuttle SRB has an Isp of 237 secs at sea level, 267 secs in vaccum. Let's take an average of 253 secs for our calculations. Let's assume a SRB mass of 145 tons with a propellant fraction of 0.85 (same as shuttle SRB). Let's assume that the Centaur Upper Stage has a mass of 25 ton, a fuel fraction of 0.90 and an Isp of 462 sec (RL10B-2).With that we are pushing a payload of 4 tons. &nbsp;Gross Delta V at 1st stage burn out = 253 x LN [(145+25+4)/(145 x 0.15 + 25 + 4)] = 3062 m/sGross Delta V imparted by Centaur Upper Stage =&nbsp; 462 x LN [(25+4)/(25 x 0.10 + 4)] = 6771 m/sTotal gross Delta V = 3062 + 6771 =&nbsp; 9833 m/sApplying a correction factor of 0.80 (based on the correction needed for the ARES I which has a similar profile...Net Delta V =&nbsp; 7866 m/This is sufficient for LEO. &nbsp;&nbsp; <br />Posted by dwightlooi</DIV><br />&nbsp;</p><p>I don't have the figures available for a correct calculation. but your assumptions are too optimistic.&nbsp; The SRB as a single segment will have to be a lower segment with the propellant cutout to accomodate nozzle gimballing.&nbsp; That reduces the propellant load.&nbsp; In addition it will have to carry the heavy lower skirt with TVA system and the heavy forward dome, increasing inert weight on a per segment basis significantly.&nbsp; The&nbsp; propellant mass fraction will be significantly reduced.</p><p>The Centaur RL 10B is designed for&nbsp;very high altitude operation with an extendible exit cone and an extremely high nozzle expansion ratio.&nbsp; That high expansion ratio cannot be used lower in the atomosphere without severe degradation in ISP from flow separation, with high loss of thust and potentially collapse of the nozzle shell.&nbsp; So you will have to use a different configuration with much lower Isp.&nbsp; Also vacuum thrust for the Centaur is in the range of 23,000 lb (even thge RL-10B is less than 25,000 lb) so with a stage weight of 25 tons you have a thrust to weight ration that is less than 1.&nbsp; That is not good for a booster, though it is acceptable for a kick motor that operates at much higher altitudes.&nbsp; </p><p>When you include realistic inert weights snd the effects of aerodynamics and gravity losses I think you will find, consistent with other studies, that a 2-stage design of this sort won't work very well even with other engines.&nbsp; The low thrust of the Centaur is a killer&nbsp;in this configuration&nbsp;though.</p><p>But it was a nice try and you did have some figures to back it up.&nbsp; </p> <div class="Discussion_UserSignature"> </div>

 

[trailrider]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;I don't have the figures available for a correct calculation. but your assumptions are too optimistic.&nbsp; The SRB as a single segment will have to be a lower segment with the propellant cutout to accomodate nozzle gimballing.&nbsp; That reduces the propellant load.&nbsp; In addition it will have to carry the heavy lower skirt with TVA system and the heavy forward dome, increasing inert weight on a per segment basis significantly.&nbsp; The&nbsp; propellant mass fraction will be significantly reduced.The Centaur RL 10B is designed for&nbsp;very high altitude operation with an extendible exit cone and an extremely high nozzle expansion ratio.&nbsp; That high expansion ratio cannot be used lower in the atomosphere without severe degradation in ISP from flow separation, with high loss of thust and potentially collapse of the nozzle shell.&nbsp; So you will have to use a different configuration with much lower Isp.&nbsp; Also vacuum thrust for the Centaur is in the range of 23,000 lb (even thge RL-10B is less than 25,000 lb) so with a stage weight of 25 tons you have a thrust to weight ration that is less than 1.&nbsp; That is not good for a booster, though it is acceptable for a kick motor that operates at much higher altitudes.&nbsp; When you include realistic inert weights snd the effects of aerodynamics and gravity losses I think you will find, consistent with other studies, that a 2-stage design of this sort won't work very well even with other engines.&nbsp; The low thrust of the Centaur is a killer&nbsp;in this configuration&nbsp;though.But it was a nice try and you did have some figures to back it up.&nbsp; <br />Posted by DrRocket</DIV></p><p>There is also the problem of changing the balance of the whole stack when you shorten the SRB, OR remove propellant.</p><p>As far as the water table at the Cape being a reason why you can't bore silos, that one was answered in the late 1950's, when the Minuteman silo was built.&nbsp; Also when the Polaris missile "cocktail shaker" (Ship Motion Simulator launch tube) was built.&nbsp; You just need big enough sump pumps!</p><p>But there is a more important question to be answered by the Ares Lite proposal... "You buyin'?"&nbsp; At this point, NASA would be admitting the Ares I/V+ is a bad idea (which IMHO, it IS!), and short of starting over with something that make some SENSE, it ain't gonna happen UNLESS, the next President AND Congress decide to go for an alternative like the Direct 2.0, etc.!&nbsp; The likelihood of that is...your guess is as good as mine, but not very likely!&nbsp; We can HOPE, of course...</p><p>Ad Luna! Ad Ares! Ad Astra!</p>

 

[dwightlooi]

<p>Pertaining to the two previous posts...</p><p>(1) The core idea here is not that it has to be the SRB 1st segment (it can be a 1.5 segment or even a non-segmented motor ala Castor 120) or if it should be paied with an RL-10 (it can be an RL-60).</p><p>(2) The ideas is that perhaps NASA should consider building a crew launch system that is as small as possible and focus on mission responsiveness rather than the ability of the capsule to carrying additional stuff and stay up for additional durations. You go with a small vehicle, build them on an assembly line in by the dozens per run and put them in silos. </p><p>(3) The Silo launch idea is for easy payload integration and increased readiness. You wheel your capsule or cargo pod or satelite out to the Silo at ground level, slide it over the launch vehcile, latch it down and you are ready to go. The launch vehicle itself is stacked and encapsulated at the time of manufacture, it is ready to launch from day 1 it is lowered into the silo and it stays ready to launch always (in part because it is always protected from the elements). I don't think the water table is an issue. We are not building a 5 story deep underground garrage here, the silos can be sealed steel vessels ala Ballistic Missile tubes on submarines. The difference being that as a hot launch silo, it is U shaped with a full bore tube coming up to the surface. When you are launching you open the covers on both ends -- the rocket goes out one end the exhaust goes out the other. </p><p>&nbsp;</p>

 

[Bytor_YYZ]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'> The Silo launch idea is for easy payload integration and increased readiness. You wheel your capsule or cargo pod or satelite out to the Silo at ground level, slide it over the launch vehcile, latch it down and you are ready to go. The launch vehicle itself is stacked and encapsulated at the time of manufacture, it is ready to launch from day 1 it is lowered into the silo and it stays ready to launch always (in part because it is always protected from the elements). I don't think the water table is an issue. We are not building a 5 story deep underground garrage here, the silos can be sealed steel vessels ala Ballistic Missile tubes on submarines. The difference being that as a hot launch silo, it is U shaped with a full bore tube coming up to the surface. When you are launching you open the covers on both ends -- the rocket goes out one end the exhaust goes out the other. &nbsp; <br /> Posted by dwightlooi</DIV></p><p>The trade for "easy" payload integration is not worth all the other problems. There still has to be a lift of the spacecraft, 2 inches or 100 feet doesn't really change things. &nbsp; And there is no increased "readiness", the silo doesn't provide anymore benefit than a tower.&nbsp;</p><p>"encapsulated at the time of manufacture"&nbsp; is not feasible.&nbsp; The solid stage would have to be shipped separately (from a different location) from the upperstage.&nbsp;&nbsp; Integration wouldn't happen until the launch site.&nbsp; </p><p> Launch vehicles are not weapons systems, which have reliability factors of less than 90% and can't be treated as such. </p><p>The tube still will have harsher environments than a tower</p><p>There aren't steel tubes that size.&nbsp; This nonviable vehicle&nbsp; would be bigger than the largest US silo ICBM, the Titan II.&nbsp; There was water in the launch deflector (the silo).&nbsp; </p><p>"it stays ready to launch always" &nbsp; No such thing.&nbsp; LV systems are made for a short duration flight.&nbsp; They are not made to be continously 'ready'&nbsp; Same goes for ground propellant systems,&nbsp; range safety systems. &nbsp;</p><p>&nbsp;The LV's in towers are just as protected from the basic elements as one in a tube.&nbsp; All sensitive volumes are purged with AC air. </p><p>This concept is filled with fatal flaws </p>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Pertaining to the two previous posts...(1) The core idea here is not that it has to be the SRB 1st segment (it can be a 1.5 segment or even a non-segmented motor ala Castor 120) or if it should be paied with an RL-10 (it can be an RL-60).(2) The ideas is that perhaps NASA should consider building a crew launch system that is as small as possible and focus on mission responsiveness rather than the ability of the capsule to carrying additional stuff and stay up for additional durations. You go with a small vehicle, build them on an assembly line in by the dozens per run and put them in silos. (3) The Silo launch idea is for easy payload integration and increased readiness. You wheel your capsule or cargo pod or satelite out to the Silo at ground level, slide it over the launch vehcile, latch it down and you are ready to go. The launch vehicle itself is stacked and encapsulated at the time of manufacture, it is ready to launch from day 1 it is lowered into the silo and it stays ready to launch always (in part because it is always protected from the elements). I don't think the water table is an issue. We are not building a 5 story deep underground garrage here, the silos can be sealed steel vessels ala Ballistic Missile tubes on submarines. The difference being that as a hot launch silo, it is U shaped with a full bore tube coming up to the surface. When you are launching you open the covers on both ends -- the rocket goes out one end the exhaust goes out the other. &nbsp; <br />Posted by dwightlooi</DIV></p><p>Launch vehicles are not build on an assembly line by the dozens.&nbsp; The only rockets built in any even vaguely resembling that are small tactical solid missiles -- a few inches in diameter at most.&nbsp; ICBM motor rates are more like one per week, per stage for full rate&nbsp;production&nbsp;and&nbsp; they are much smaller than space launchers.&nbsp; The infrastructure for the production rates of which you speak simply do not exist, and the demand for launchers does not support building such an infrastructure.&nbsp; For large motors there is not such thing as a run or a lot,&nbsp; At least for the solids each individual motor is carefully built and variations in material lots are considered in making the specific propellant mixes that go into the motor.&nbsp; Smaller motors can be made in larger lots because you can cast several motors from one propellant mix.&nbsp; Larger motors require several propellant mixes per motor.</p><p>Hot flyuouts can be done, but it is not so easy as&nbsp;you imagine.&nbsp; Minuteman does it, but Peacekeeper did not.&nbsp; Those rockets take off pretty quickly -- I am not sure that a manned mission would allow the g forces.&nbsp; And if you take off slowly there is likely to be a plume heating issue. </p><p>The key to constant readiness is storable propellant.&nbsp; These days that generally&nbsp;means solids.&nbsp; It certainly means that you cannot use LOX as the oxidizer, and you cant't use liquid hydrogen as the fuel.</p><p>But you don't need launch on demand and constant readiness for a space launcher, so why go that route and pay the penalties when you don't have to ?&nbsp; There is no particular benefit to a silo for payload integration.&nbsp; <br /></p> <div class="Discussion_UserSignature"> </div>

 

[dwightlooi]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Launch vehicles are not build on an assembly line by the dozens.&nbsp; The only rockets built in any even vaguely resembling that are small tactical solid missiles -- a few inches in diameter at most.&nbsp; ICBM motor rates are more like one per week, per stage for full rate&nbsp;production&nbsp;and&nbsp; they are much smaller than space launchers.&nbsp; The infrastructure for the production rates of which you speak simply do not exist, and the demand for launchers does not support building such an infrastructure.&nbsp; For large motors there is not such thing as a run or a lot,&nbsp; At least for the solids each individual motor is carefully built and variations in material lots are considered in making the specific propellant mixes that go into the motor.&nbsp; Smaller motors can be made in larger lots because you can cast several motors from one propellant mix.&nbsp; Larger motors require several propellant mixes per motor.Hot flyuouts can be done, but it is not so easy as&nbsp;you imagine.&nbsp; Minuteman does it, but Peacekeeper did not.&nbsp; Those rockets take off pretty quickly -- I am not sure that a manned mission would allow the g forces.&nbsp; And if you take off slowly there is likely to be a plume heating issue. The key to constant readiness is storable propellant.&nbsp; These days that generally&nbsp;means solids.&nbsp; It certainly means that you cannot use LOX as the oxidizer, and you cant't use liquid hydrogen as the fuel.But you don't need launch on demand and constant readiness for a space launcher, so why go that route and pay the penalties when you don't have to ?&nbsp; There is no particular benefit to a silo for payload integration.&nbsp; <br /> Posted by DrRocket</DIV></p><p>A hot lift off is actually safer than a cold lift off like that of the Peacekeeper. The advantages to a cold lift off is that you do not need the exhaust ducts, just a cold gas generator to eject the missile out the tube before its motor ignites. However, a cold launch also means that should the motor fail to ignite there is no benign way to abort the launch, the missile will crash back down and probably blow up.</p><p>This idea behind readiness does not surround storable propellants. I guess one can use a solid with one or two N204-Hydrazine upper stages. But that will result in a larger rocket for the given payload weight. The idea is to build the smallest possible launch vehicle to lift 4 tons into orbit, build them in quantity and store them in a ready to fuel and launch state at a Silo farm. Instead of having one integration tower and the need to do move your launch mannifest through it sequentially, You simply wheel the paylod out to a farm of say 24 Silos, the majority of which housing ready to go boosters. You fuel up one, wheel the payload over it, snap it on and launch. If there is a problem with a booster, you use one of the dozen others sitting at the farm.</p><p>The small size of the vehicle makes the wheel over, clamp on style of integration possible. It also makes the building of a silo farm feasible.&nbsp;</p>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>A hot lift off is actually safer than a cold lift off like that of the Peacekeeper. The advantages to a cold lift off is that you do not need the exhaust ducts, just a cold gas generator to eject the missile out the tube before its motor ignites. However, a cold launch also means that should the motor fail to ignite there is no benign way to abort the launch, the missile will crash back down and probably blow up.This idea behind readiness does not surround storable propellants. I guess one can use a solid with one or two N204-Hydrazine upper stages. But that will result in a larger rocket for the given payload weight. The idea is to build the smallest possible launch vehicle to lift 4 tons into orbit, build them in quantity and store them in a ready to fuel and launch state at a Silo farm. Instead of having one integration tower and the need to do move your launch mannifest through it sequentially, You simply wheel the paylod out to a farm of say 24 Silos, the majority of which housing ready to go boosters. You fuel up one, wheel the payload over it, snap it on and launch. If there is a problem with a booster, you use one of the dozen others sitting at the farm.The small size of the vehicle makes the wheel over, clamp on style of integration possible. It also makes the building of a silo farm feasible.&nbsp; <br />Posted by dwightlooi</DIV></p><p>What do you mean by safer ?&nbsp; Are you aware of any launch failures do to a failure to ignite ?&nbsp; The closest of which I am aware was the first launch of Peacekeeper and that was due to steam condensation on the propellant.&nbsp; It actually ignited pretty well and the condensation problem was subsequently corrected.&nbsp; By the way the gas used to eject missiles from tubes is only cold compared with the flame temperature of the rocket propellant.&nbsp; It is actually pretty hot by normal standards.&nbsp; Those gas generators use some pretty energetic materials.</p><p>And you do need to be very careful with the gas dynamics of a hot gas flyout.&nbsp; It is not quite as straightforward as you might think with large motors, and anything that puts 4 tons into orbit is a large vehicle, larger than an ICBM.&nbsp; The Titan IVB was not a tube launch by any means.&nbsp; But the gas dynamics in the flame bucket was sufficiently much of a concern that steps were taken to protect the SRB nozzles and TVA systems from side loads induced by gas dynamics.&nbsp; And the problem was sufficiently complex that even some pretty advanced computational fluid dynamics could not quantify the effect.</p><p>The purpose of silos is not to provide readiness, although they do that.&nbsp; The purpose is to provide hardness in case of a nuclear attack.&nbsp; It is not all that great of an environment, snd some of the silos have been pretty wet.&nbsp; And that was not in Florida.&nbsp; I think a silo farm would actually be more expensive to maintain and operate than would the launch pad system that is in place.&nbsp; There are advantages to having direct access to the booster before launch in terms of assuring that all systems are ready and providing for reliability.&nbsp;&nbsp; If I were going to be riding the rocket you can be assured it would not be coming out of a silo after months or years of storage.&nbsp; That also goes for an expensive payload if I had any responsibility for it.<br /></p> <div class="Discussion_UserSignature"> </div>

 

[Bytor_YYZ]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You fuel up one, wheel the payload over it, snap it on and launch. If there is a problem with a booster, you use one of the dozen others sitting at the farm.</DIV></p><p>&nbsp;</p><p>You have no idea on how things. &nbsp;&nbsp; No such thing as snap it on, spacecraft integration takes a few days. &nbsp;</p><p>&nbsp; As where is the $$ to maintain all the silos and "ready" to fly vehicles.&nbsp; Again, launch vehicles are not ICBM's.&nbsp; This concept&nbsp; only works in a fantasy world. &nbsp; </p>

 

[samkent]

How many people have said “It won’t work – You can’t do that” through out the ages. I think the purpose behind the ideas has merit. A quick launch vehicle has a variety of uses. Most importantly as an emergency rescue vehicle. Or ISS crew swap. <BR/>You can’t get launch costs down until you can stock pile and pull components off the shelf

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>How many people have said &ldquo;It won&rsquo;t work &ndash; You can&rsquo;t do that&rdquo; through out the ages. I think the purpose behind the ideas has merit. A quick launch vehicle has a variety of uses. Most importantly as an emergency rescue vehicle. Or ISS crew swap. You can&rsquo;t get launch costs down until you can stock pile and pull components off the shelf <br />Posted by samkent</DIV><br /><br />No one said it won't work.&nbsp; We said it is counter-productive, would raise costs, require new infrastructure and work counter to high reliability.&nbsp; It will work.&nbsp; It is just not particularly smart to make it work.&nbsp; </p><p>A good deal of recent&nbsp;cost reduction in modern industry is the result of ending the practice of stockpiling and pulling components off the shelf.&nbsp; Why do you think that rockets are so different?&nbsp; Just in time manufacturing along with a host of other techniques&nbsp;to reduce costs by improving quality and reliability have been successful in many industries, under the name of the "Toyota System".&nbsp; I am familiar with at least one major manufacturer of rockets who has a&nbsp;focused program to implement that system.&nbsp; </p> <div class="Discussion_UserSignature"> </div>

 

[marko_doda]

<p>It could work, but making a 3 person capsule with no cargo capability is not what we need now, the ISS needs 7 people, the moon & mars missions will need 4 people minumum, and the tourist industry would want more people per flight.</p><p>Also, it isn't just to shrink it, you must also develop a new solid fuel mixture that will burn slower (or use an booster of the same lenght with smaller daimeter ), other things too will need to be changed.</p><p>If you like to reduce the time a rocket prepares for launch you don't need to shrink it, you just need to simplify the preparing procedure, you asemble the payload fairing in a clean room, then connect all the stages of the rocket and the payload in a simple hangar. If it is light take it by a trailer to the launch site, if it is heavy use a train, both are faster than a crawler. Lift it there with a large crane, tank it up with fuel and launch.</p><p>This is how the russians and SpaceX prepares their rockets, and it is pretty quick. </p>

 

[tanstaafl76]

<p>I don't see the point of an Ares Lite. &nbsp;The Ares I program was started in order to serve as a safe and reliable foundation for getting a large capsule in orbit as a precursor for trips to the Moon and Mars, not just to ferry people to the ISS. &nbsp;At this point it would be silly to design a NASA rocket from scratch just to serve the ISS imho. &nbsp;I'd rather they contract that out to commercial space companies that can demonstrate their ability to handle the task safely. &nbsp;New NASA rockets should be designed as a long term orbital delivery system for exploration of our solar system, not just a glorified orbital taxi cab.</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> </div>