EELVs as manned launch vehicles.

[drwayne]

You know, I had never heard that part about the engine hanging from the TVC. It makes sense, considering the spatial magnitude of the oscillations before the engine was shut off.<br /><br />The point I was trying to make earlier was that it was far from a routine shutdown/the monitoring systems worked properly/no big deal.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[padrat]

>>A major task in man-rating the EELVs would be incorporating a vehicle health detection system that will give you an early warning that things were going South such that you have enough time to get out of town. Can such a system be incorporated into the EELVs? I think so, but others have their doubts. <<<br /><br />As part of a team that evaluated both Boeing's and LM's work on human-rating EELVs, I can give you an unequivocal "yes". They can be human-rated, and without breaking anyone's piggy bank.<br /><br />P.S. What NASA doesn't tell anyone is that Shuttle does NOT meet human rating requirements.<br /><br />-Pad Rat-

 

[padrat]

>>Does anyone know the safety record of Shuttle as compared to the Apollo with Saturn ? Since the Saturn launch vehicle was the last thing we had before the STS, and it closest resemblerance to the EELVs, it would interesting to compare the safety record of this two very different launch system. <<<br /><br />Saturn V performed ten successful crewed flights and killed no one. It had a competent health monitoring system that safely handled ascent problems. It was robust design with good performance margins. It was even hit by lightning and took it in stride. Saturn V was the first US booster designed from the outset as a human-rated booster.<br /><br />Shuttle has killed 14 people. Yes, I do consider STS-107 a launch accident, because the ascent is the phase during which fatal damage was incurred. Shuttle is not human-rated by current NASA standards. It is not robust. Look at it wrong and it's damaged. It's a glass lady. I know 'cause I used to work on it.<br /><br />-Pad Rat-<br />

 

[padrat]

>>Also, I don’t know how long the life support systems need to able to support the crew, but 12 hours worth of oxygen seems a bit low. I would expect something able to support the crew for at least 3 or 4 days. It would allow more freedom for timing the launch since the cev can take more time to reach the station and it would allow more freedom on timing the return (i.e. bad weather at sight). <<<br /><br />The program requirement for CEV is the capability to provide life support for a 16-day mission.<br /><br />-Pad Rat-<br /><br />

 

[padrat]

>>On paper it would seem that STS compares favourably to Saturn. <<<br /><br />Saturn V/Apollo had an abort system that provided nearly 100% safe abort capability (there was a very brief time coming off the pad when abort was iffy). <br /><br />Shuttle abort is more like "a wing and a prayer". Everything has to go just right during abort or you're cooked. And there are black zones during which no abort is possible.<br /><br />STS-107 was definitely a launch failure. Your launcher is not supposed to inflict fatal damage on your payload.<br /><br />-Pad Rat-

 

[padrat]

>>One problem might be acceleration, unmanned vehicles are usually subjected to much higher values because it is more efficient, less gravitational loss.<<<br /><br />Peak acceleration on the EELVs is about 5gs. The Delta IV Heavy demo didn't even reach 5. <br /><br />Dig a little bit and see how many g's the early astros pulled on Redstone, Atlas and Titan. They were NOT inconsequential.<br /><br />-Pad Rat-

 

[padrat]

>>I beg to differ. The damage was done during launch, however the launch was 100% sucessful. The vehicle was inserted into the correct orbit and all on-orbit mission goals were achieved. The question being raised was a comparison of STS to Saturn as a launch system.<<<br /><br />A good launch system does not fatally damage its payload during ascent. <br /><br /> />>The root cause of the failure was a high-velocity impact on the wing leading edge, it just happens that the impactor was shed from the launch vechicle itself - it could just as easily have happened on-orbit (MMOD), or by flying into a goose!<<<br /><br />True, but it happened during ascent. Strikes in space may or may not be avoidable, but it was a written requirement that pieces of the launch system were NOT supposed to hit the orbiter. Had the STS program been doing its job - and following its own rules - that foam would not have come off. In the case of STS-107 the *launch system* effectively killed the crew.<br /><br />-Pad Rat-<br /><br />

 

[drwayne]

I wouldn't say it took getting struck by lightening "in stride" exactly. It took some "not in the books" recovery by the pilot to overcome the reset caused by the strike. It did however, not bite the cookie, and was recoverable, so the point that the design proved robust in this case is certainly valid.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[drwayne]

OK, booster versus payload...got it!<br /><br />Wayne<br /><br />p.s. Did I ever tell you my father, while working for IBM in those days, worked on the IU /> <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[dwightlooi]

IMHO, <b>the fundamental problem with the STS is in the design</b>. You have the re-entry vessel (the shuttle in this case) fully exposed to the aerodynamic rigours of launch hanging to the side of the main tank and between two solid boosters. Actually, its not only to the side, but downstream of the aerodynamic "front" as well. Add to that the fact that you have two huge solids providing the majority of lift off thrust and three of the most complex, highly stressed engines doing the driving, and you don't have a theoretically very scary combination? To make matters worse, the shuttle employs non-contiguous, tagged on tiles for thermal protection. These are prone to falling off and just about every shuttle mission had returned with missing tiles. A thick, continuous, sprayed on ablative heat shield would be a lot more robust, but it cannot be used on the shuttle because the latter is a reusable vehicle. <b>Imagine hanging an Apollo command module upside down, half way up the Saturn V booster and launching it that way -- aren't you asking for trouble?</b><br /><br />ELVs generally do not expose the hot side of the re-entry capsule to either the supersonic shock stream or any possible falling debris since the capsule is usually at the tip of the LV with the hotside facing down. Some systems, like the Soyuz or Shen Zhou even encloses the capsule in a fairing (just like with satelite payloads. Last but not least, just about all the capsule systems have a launch escape system.<br /><br /><b>I think the EELVs can be employed in a new system for manned missions. This should include a A CTV (4-man, 12 hour endurance) for orbital transfers, a CEV for exploration and extended missions (No re-entry capability, crew launched separately on a CTV) and a DCC dumb cargo capsule for bringing supplies to the ISS or a CEV. Only the CEV should require a heavy lift booster (Delta IV), the CTV and CTC can be launched on zero solid, single engined versions of both the Atlas V and the Delta I</b>

 

[najab]

><i>A thick, continuous, sprayed on ablative heat shield would be a lot more robust, but it cannot be used on the shuttle because the latter is a reusable vehicle.</i><p>I wouldn't want to fly in a vechicle with a "sprayed on" heat shield - you think bonding is a problem with tiles, wait till you try it with a liquid. At least you can pull-test a tile!<p>The Apollo heatshield compound wasn't sprayed on, it was 'syringed' into holes on the bottom of the capsule.</p></p>

 

[padrat]

Just as a "by the way", the first couple of STS missions did fly with ablative applied to a few locations that engineers thought would be troublesome. One of the guys I work with told me about the ablative dripping on the lakebed after landing at Edwards.<br /><br />-Pad Rat-

 

[drwayne]

There were especially a lot of people employed in Apollo in Huntsville. <img src="/images/icons/smile.gif" /><br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[mrmorris]

<font color="yellow">"I wouldn't want to fly in a vechicle with a "sprayed on" heat shield ..."</font><br /><br />You wouldn't want to fly on G-X3 using the ablative shield I specced out for it? I'm devastated. I'd counted on you as being among the first 10,000 to sign up to be a test pilot for it... <img src="/images/icons/smile.gif" />

 

[najab]

Okay, maybe I'll ride G-X3 - we were planning to use a robot arm to physically paint on the ablative weren't we?

 

[mrmorris]

<font color="yellow">"...we were planning to use a robot arm ..."</font><br /><br />That was the suggested implementation, yes.