Why not kill the Altas and Delta programs?

[bdewoody]

Historically it's never good to put all of your eggs in one basket, even if the one basket seems to be a good design.<br /><br />Before WWII the Navy thought it had a great design for torpedos so they only had one design built and only by one manufacturer.<br /><br />After the war started and several submarines with great captains were lost they found that the torpedo had a fatal flaw.<br /><br />We will do well to keep as many sources as possible open to make our space vehicles. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[edkyle98]

>"The SRB is also the simplest and cheapest booster type that can be made. There is no turbomachinery, no pressure tanks, no insulations, none of that. Basically, its a tube with solid propellant poured into it. The only "complicated" part being the thrust vectoring nozzle. And this is still no more complicated than the typical gimbal for liquid engines. "<<br /><br />An SRB is not even close to being just a tube with solid propellant poured in. The motor segments consist of steel casings that have to be relined with a layer of vulcanized rubber insulation and a layer of liquid rubber liner before any propellant is poured. The insulation is needed because the propellant burns at 6,000 degrees F while steel melts at 2,500 degrees F. The steel is needed to withstand the 912 psi pressure generated by the burning propellant. The liquid rubber liner is needed to give the propellant something to "stick" to. If it doesn't stick, if voids are left between the propellant and the liner/insulation, catastrophic destruction of the motor can result.<br /><br />Then there are the joints, factory and field, with their fussy o-rings and fastener systems. And the movable nozzles, which must withstand the highest temperatures in the motor. And the triple-redundant avionics, with their APU power supplies, and the separation motors, and the igniter, and the recovery systems, etc.<br /><br />No. Not merely tubes.<br /><br /> - Ed Kyle

 

[frodo1008]

The EELV program was NOT funded by NASA, but by the US Military. Its specific purpose was to maximize the reduction of cost of rocket launches while still using current and proven rocket technology. The program reduced the high cost of placing a pound of material into LEO from over $10,000 per pound to LEO to less than $5,000 per pound to LEO. <br /><br />However it is still very difficult for the US to compete with the likes of Russia and China in this market, as their labor costs are far less. Not because they have better systems, but simply because they can pay their people far less as the cost of living in those countries is so much less than the US. <br /><br />However, as it is the US taxpayer that is paying for NASA, NASA would not ever use such systems to directly launch US astronauts into space. It just will not happen, so forget it!!!<br /><br />The RS68 engine that powers the Common Booster Core of the Delta IV was deliberately designed to be inexpensive. The original cost was designed to be less than $7 million and would have made the cost of a CBC in the $15 million per unit range, this was when the cost of a four segment SRB was about $40 million (without the development costs of the newer units). <br /><br />Also, as every liquid engine (at the very least at Rocketdyne in this country) is given a "Green Run" which is a full power run, and then the very same engine is used for the actual launch (something that is utterly impossible to do with a solid engine). liquid engines are inherently safer than solids. So despite their relative complexity and moving parts, which jet engines and even automobile engines also have (power units whose safety we all rely on all the time) liquid engines are safer than solid units! Indeed one of the legitimate reasons for the relative high cost of the Space Shuttle SRB's is the high cost of the extreme high quality needed to guarantee that each engine is exactly the same as engines that are tested, as it is impossible t

 

[rocketman5000]

Very nice analysis

 

[j05h]

<i>> So the arguments of the original poster of this thread are therefore at the very least misinformed. </i><br /><br />Basically the USA is missing a capsule for guaranteed human access. We have the rockets, the factories lie idle parttime and we have the infrastructure. All we're missing is the vehicle on top. This is far in advance of the ARES I/CEV in many ways, and Lockheed is interested in expanding what it does in space. <br /><br />Thanks for the info about "Green Runs", definitely can't do that with the (finicky, dangerous) SRB.<br /><br />I don't think we can achieve CATS yet, but we can create space product/projects that make money with what is almost available. Incremental development, ISRU and sheer number of flights will eventually create a CATS breakthrough. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[rocketman5000]

Would there be an advantage of developing a standard interface between rocket and return capsule? It seems like this might open up the market to more companies wishing to make crew capsules, or cargo capsules or maybe even satelittes<br /><br />Maybe the interface would be broken down into weight classes (volume) of capsules. <br /><br />Have a <br /><br />Class A Interface - would be able to support a crew capsule for up to 3 persons on an LEO delivery trip,<br /><br />Class B Interface - would be able to support a crew up to 7 persons on a LEO visit<br /><br />Class C Interfeace - would be able to launch heavy cargo or larger inter planetary spacecraft. <br /><br />

 

[propforce]

<blockquote><font class="small">In reply to:</font><hr /><p>Also, as every liquid engine (at the very least at Rocketdyne in this country) is given a "Green Run" which is a full power run, and then the very same engine is used for the actual launch (something that is utterly impossible to do with a solid engine). liquid engines are inherently safer than solids. So despite their relative complexity and moving parts, which jet engines and even automobile engines also have (power units whose safety we all rely on all the time) liquid engines are safer than solid units! <p><hr /></p></p></blockquote><br /><br />EXCELLENT POST frodo !! <img src="/images/icons/smile.gif" /><br /><br />I might add that, a "green run" does more than just validating an engine's operation, it improves engines performance reliability. After the first run, the engineers may do additional "trim run" after some adjustments (changing orifice diameter, for example) to better zero-in engine pefromance parameters. The RL-10s for example, can do upto 3~4 "green runs" to insure the engine meets its performance spec.<br /><br />This ability, as compared to solid motor (pour once and you get what you get), is what assures liquid rocket engines safety and performance.<br /> <div class="Discussion_UserSignature"> </div>

 

[j05h]

<i>>Would there be an advantage of developing a standard interface between rocket and return capsule? It seems like this might open up the market to more companies wishing to make crew capsules, or cargo capsules or maybe even satelittes... Maybe the interface would be broken down into weight classes (volume) of capsules. </i><br /><br />Yes! I call it "payload neutrality", i'm not sure if there is an engineering term for it. There are some rockets that share satellite adapters, but not crew craft, yet. If Delta, Atlas, Ariane and Zenit could compete for human payloads, we'd have an actual market evolving. <br /><br />What I would like to see implemented would be a merger of docking adapter and payload apapter. The payload versions would be a berthing ring without hatches, docking adapters include sealable hatch/tunnels. For instance, a capsule might have a payload adapter on the base of it's service module, with docking adapters between descent capsule and any mission modules and a final hatch at the top for docking. Capsules should be able to leave mission modules in space, like Shen Zhou, esp attached to a station. This allows a true "tinkertoy" approach, in which components and stages can be attached in various ways, then reconfigured as needed. <br /><br />The interfaces might be for a 3-seat capsule (Soyuz class 5-10ton), 7-15 seat "heavy" capsule (10-25t) and a larger "infrastructure" interface that includes a very large (3-5m) hatch for 30-100t payloads (which become affordable w/ frequent flights, following EELV upgrades). Payload adapters should match hatch ring sizes and be androgynous (the tug that brings your capsule to L1 turns around and brings an ISRU tanker back to LEO). For now, a spec the entire industry could agree on using a basic 5-10t capsule would be great. <br /><br />Back in reality, the Dragon is being designed to use any of three adapters: CBM, LIDS or APAS. I'm not sure but assume that the payload adapter for Falcon is custom. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[drbobguy]

<blockquote><font class="small">In reply to:</font><hr /><p>During WWII, roughly 1 in 40 US military was killed.<p><hr /></p></p></blockquote><br /><br />More than 1 in 10 people living in the Soviet Union were killed in the period 1939-1945. I don't know what the figure as a percentage of the military was, but the Soviet Union lost twenty times more troops than the United States.