Re: NASA's grand plan to revive human exploration...

[gaetanomarano]

"...capsules are unsafe..."<br /><br /><br />in the last 20-30 miles a spacecraft is EXACTLY THE SAME of a airline plane, same forces, same situations, same emergencies, so, if parachutes are better and safer than wings, why (civil and military) airplanes lands with wings instead of parachutes?<br /><br />please, ask astronauts (since THEY will fly with that vehicles) if they prefer to have wings or not!

 

[gaetanomarano]

"...Discover/Corona..."<br /><br />...unmanned Discover/Corona...<br /><br />...again, ask astronauts if they prefer to fly on reentry with a winged vehicle to control like an airplane (+ emergency personal parachutes) or a "falling-rock" capsule with excellent parachutes only...<br /><br /><font color="yellow">capsule parachute = ONE (and ONLY) chance to land alive<br /><br />wings + (double) personal parachutes = THREE (better) chances to land alive and MUCH TIME to "think" and "act" in case of emergency!!! (5-10 minutes with a winged vehicle instead of a FEW SECONDS with a "falling-rock-capsule")</font><br /><br /><br />

 

[gaetanomarano]

"...And as for parachutes being inherently dangerous, well people use them every day..."<br /><br />I think that the number of passengers dead with a plane (in respect of passengers per year) is much less than people dead with parachutes (in respect of launches per year)<br /><br />plane crashes are well known because, when happen, they are seen on TV while deads with parachute don't breaks the news!<br /><br />I think that, if the captain of the airplane you are flying, will commands you to jump with a parachute from 20,000 feet (instead of land with plane wings), you will be peoccupied, not happy!<br /><br />many refer to Shuttle as a "spaceplane" and to Challenger like a "spaceplane disaster" but this is a BIG mistake! <br /><br />due to bad design, Shuttle is NOT a "spaceplane" but only a (dangerous) "ROCKET with wings" that may explode at every launch! (like any rocket, like the first Ariane5 and like CEV rocket...)<br /><br />this is the main reason I suggest to use it as a crewless cargo [ www.gaetanomarano.it/spaceShuttle/spaceshuttle.html ] or STOP Shuttle flights NOW!<br /><br />Shuttle works as a "spaceplane" only on reentry and landing, when, if not damaged, it is 100% safe! (as 100+ landings demonstrates, except Columbia with DAMAGED wings)<br /><br /><br />

 

[drwayne]

Wowsers. Thats a head shaker.<br /><br />Wayne<br /><br /> <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[gaetanomarano]

<br /><br />again... why do you hate Shuttles and wings?<br /><br /><br />about CEV and wings:<br /><br />capsule parachute = ONE (and ONLY) chance to land alive <br /><br />wings + (double) personal parachutes = THREE (better) chances to land alive...<br /><br />and MUCH TIME to "think" and "act" in case of emergency!!! (5-10 minutes with a winged vehicle instead of a FEW SECONDS with a "falling-rock-capsule") <br /><br /><br />about Shuttle:<br /><br />Shuttle: 25 tons payload TO-DAY<br /><br />SDLV: 70-120 tons (if works) in 2015<br /><br />what is your choice if you need to launch heavy payloads in 2007, 2009, 2012, etc.?<br /><br /><br />why do you WANT that MY opinions MUST BE the same of YOUR opinions?<br /><br /><br />

 

[nacnud]

I don't hate the STS I just think that for the VSE it is heavier, costlier, riskier, and less capable than a capsule.

 

[gaetanomarano]

<br /><br />only an astronaut can give us the TRUE answer<br /><br />

 

[tap_sa]

The only proper wings in space are in astronaut's patch <img src="/images/icons/tongue.gif" /><br /><br />gaetanomarano: Your comparison of capsule relying 'only' on parachutes while shuttle has triple redundancy (wings+double personal chutes) sucks hard vacuum. If orbiter's wing fails you are dead as a dodo no matter how many personal chutes you have.<br /><br />And capsules have redundancy with the chutes, for instance Apollo had three chutes, two were perfectly safe for landing, even one might have been survivable.<br /><br />Early Vostoks had personal chutes. Gagarin didn't land in the capsule but ejected midair, this was part of nominal Vostok mission.<br /><br />If all capsule chutes would fail but it had ejection seats a la vostok the crew would have time to bail out. Even chuteless capsules reduces speed below subsonic before hitting ground, making ejection condition pretty bening compared to what some fighter jet seats are designed for.

 

[drwayne]

I don't "hate the Shuttles and wings". I understand them, I understand their mission *quite* well.<br /><br />I don't get emotional about concepts or designs for ships. Once can not afford that luxury in real life.<br /><br />The post I was commenting on was the one in which your used the word same to describe the conditions under which a conventional aircraft operates versus the shuttle - when in fact the boundary conditions are quite different.<br /><br />Your continued use of terms such as "ZERO" and "same" suggest a level of hyperbole and emotionalism that are the enemies of good judgement.<br /><br />You are talking to some folks here who, in many cases have been in the aerospace industry for many years. We are not stupid. And we do not in general respond well to people who push a point of view in an emotional or argumentative way.<br /><br />Take the level of emotionalism down a few notches. Discuss. Analyze. A dialog in which you converse is more effective than just a monolog in which you try to argue a point into acceptance.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[gaetanomarano]

<br />"...Your comparison of capsule relying 'only' on parachutes..."<br /><br />not only!<br /><br />see my previous post in page 3 (of 5) of this forum, you will find more capsule problems<br /><br /><br />"...capsules have redundancy with the chutes, for instance Apollo had three chutes..."<br /><br />but ONLY parachutes!<br /><br /><br />"...Gagarin didn't land in the capsule but ejected midair..."<br /><br />Gagarin was very lucky in respect of CEV crews; in Vostok mission the parachute launch was planned and he had the parachute, CEV crews (probably) will have not personal parachutes (but if they will have them... the time of CEV falls will be the same of Vostok or LESS, but, in the same, or less, time, launches must be FOUR-SIX in a few seconds instead of ONE launch... astronauts will lands with a ton of adrenaline!!!!)<br /><br />"...had ejection seats..."<br /><br />Vostok was "one astronaut - one door", CEV will be "four to six astronauts - one door", they must open the door manually and jump one a time (I don't want to be the #6...)<br /><br /><br />"...capsules reduces speed below subsonic..."<br /><br />yes, the same speed of a jet, but falling like a rock, not gliding... (100 times less time before crash!!!)<br /><br /><br />

 

[gaetanomarano]

"...emotionalism..."<br /><br />yes, I use some hyperbole like "zero" and "same"<br /><br />I well know that "zero" never is "true zero" and that "same" never is "true same" and that a Shuttle is not exactly "same" as an airplan (I'm not stupid...)<br /><br />but Shuttle is 95% like an airplane and 5% like a capsule<br /><br />planes are safer than capsule simply because civil and military planes have thousands safe flights and lands per day with only a few accident per year and the Shuttle have 100% safe landings (when it lands WITH wings) while capsule has many risks and have had many problems (and more will have when flights will multiply)<br /><br />I explain LOTS of good reasons to demonstrate that, but I receive an answer only when a post contain a little error<br /><br />I feel that the choice was ALREADY DONE: CEV without wings (and Shuttle with crew only) so the "CEVpollo" fans (in space.com forums and out of it) don't like critics but only want supporters of this "brilliant" idea<br /><br />do you want an evidence of that?<br /><br />well... in another space.com forum I've explained why (I think) the return to moon is useless and I've asked for a list of useful things to do on the moon that worth the cost...<br /><br />well... so far I've received NO answers and NO lists!!!<br /><br />(I will post here part of my comments about, so you and other readers may judge)<br /><br /><br />

 

[barrykirk]

There are other reasons to make the wings versus chutes comparison than safety alone.<br /><br />There is also the mission capability and cost issues.<br /><br />The crew needs a safe place to travel upstairs and return. That is a fundamental requirement.<br /><br />They need to return to a pre-arranged spot on the surface of the earth that is also a fundamental requirement.<br /><br />Advantages of Wings,<br /><br />1) More accurate on exact landing spot.<br />2) Safer, if the wings are undamaged.<br /><br />Advantages of Chutes,<br /><br />1) Lighter, allows more mass to be launched with the same size rocket.<br /><br />2) Lower aerodynamic drag on liftoff, less fuel wasted punching through Max-Q.<br /><br />2) Works better with water landings. (Wings would be a problem with a water landing. )<br /><br />3) On the ascent stage, I beleive, although this is just an uneductated opinion that a capsule would be safer.<br /><br />Yes you could mount a plane on top of a stack, where it would be safer than the current location of the shuttle.<br /><br />In the case of a RUD event on the stack, it is possible that wings could be damaged, at which point they aren't as safe. A capsule would be damaged in a similar way, but it would tend to be stronger and a smaller target for debris. Also, the parachutes would be protected by the rest of the capsule.<br /><br />In the case of a RUD event of the stack on the launch pad, and yes that does happen. A capsule can easily be launched high enough by an escape tower for the parachutes to deploy. For a winged vehicle, you would need a much larger escape tower to ensure that the wings had enough altitude and/or velocity to function properly. In that event you need to find a runway to land on.<br /><br />From a KSC launch, there are a few minutes at the beginning of the launch, if you lose the external tank, your ditching in the atlantic. Not as easy with wings as with chutes.<br /><br />Has anyone seen an ejection seat with wings?<br /><br />

 

[tap_sa]

<font color="yellow">"2) Safer, if the wings are undamaged. "</font><br /><br />Would you elaborate this? What makes undamaged wing safer than (undamaged?) parachute/-glider?

 

[gaetanomarano]

I think that the entire CEV-SDLV-LEM2 architecture is wrong!<br /><br />If you start from announced NASA plan (that, I'm sure, will be completely changed) the problems you list "may be" problems<br /><br />I think the main question is if that "plan" is really good; the best, safer, economic and smart "plan" possible!<br /><br />I think: "ABSOLUTELY NO!" (another hyperbole...)<br /><br />as an example: why we accept the idea that the vehicles to go in earth orbit and in lunar orbit must be the same?<br /><br />if we accept it as "the best idea", wings may be an useless weight... (so, without, we save weight and money...)<br /><br />about sea landing... this may happen also to airplanes, helicopters, paragliders, parachuters, spaceships, cars, etc. but no one of them are build to land in sea (excluding some special planes) because it is an accident!<br /><br />planes are made to land ON EARTH (in fact, no one of them have a Mercury outboard engine...)<br /><br />in case of sea landing, a (winged) spaceship's crew will have the parachutes and the TIME to jump out of ship, while airline's passengers may only dead drowned! (so, a winged spaceship, not only is safer than a capsule, but is also BETTER and SAFER than commercial airplanes!!!)<br /><br /><br />...CEV may land on snow... do you want to add a pair of ski?<br /><br /><br />

 

[strandedonearth]

The biggest problem with a winged reentry vehicle is that you have to rag those wings and landing gear all the way to orbit, significantly reducing the usable payload for a given booster. Also, to avoid the debris problems of the side-mounted shuttle, the vehicle would need to be on top. But wings near the nose of a rocket will make it unstable, requiring more TVC capability.<br /><br />A capsule can safely land anywhere, with little extra danger. A winged vehicle that can't make a runway is in serious trouble.

 

[gaetanomarano]

"...reducing the usable payload..."<br /><br />winged ship must be for crews and its life support, payloads must be sent in orbit with rockets and crewless Shuttle (while waiting for new SDLVs)<br /><br /><br />"...requiring more TVC capability..."<br /><br />a problem that NASA is able to resolve (like with Shuttle and thousands other)<br /><br /><br />"...in serious trouble..."<br /><br />if a serious trouble will happen, crew must ESCAPE the ship, NOT land anywere; with a winged ship they have many minutes (gliding), with a caspule only a few seconds (falling like a rock)<br /><br /><br /><br /><br />

 

[josh_simonson]

It's not very often you have to abort in the final minutes of landing. What's the scenario where the astronauts have to bail out once it's re-entered and gliding around in a controlled fashion? Landing gear failure? Flat tire? Wrong turn?

 

[gaetanomarano]

"...backup parachute..."<br /><br />you can add two backups or more...<br /><br />but following this game, I can add a parachute to the little crew plane, parachutes may be bigger than for a capsule but may be done (in the plane there is much space than capsule!), or main + backup or main + two backups or main + three backups + main personal astronauts parachutes + two backup personal astronauts parachutes or or or or...<br /><br />... my version will be always better... it's an intellectual game<br /><br />the crew-only-mini-shuttle has many other advantages vs. capsule (as I've expained in my previous posts) and, about security, wait the next post, with a drawing, in answer to josh_simonson's post<br /><br /><br /><br /><br /><br />

 

[aftercolumbia]

The SRB's probably use a lower operating pressure than the SSME's<br /><br />"If pure liquid engines could indeed use only pressure-fed systems they would already be doing so as such systems would indeed be much less complex than turbopumps."<br /><br />Some do, Armadillo Aerospace does, I haven't checked other X-prise competitors, but I'd expect some of them too as well. Diamant, France's first orbital launch vehicle, used a pressure-fed first stage.<br /><br />"...I just don't see a pressure-fed system of any kind being able to empty out the volume of the external tank through the three SSMS's (sic?) through the full 8.5 minutes of their running tme!"<br /><br />That is crazy! Using LH2 in a pressure-fed system is suicide because of LH2's low density. The tank wouldn't get any lighter using LH2 and wouldn't get any heavier with denser propellants ('cept probably slosh baffles, usually not needed with LH2.) Also, SSME operating pressure is far higher than is sane for a flight pressure-fed system.<br /><br />"...My own choice for this would then be the excellent RS68 which powers the Delta IV."<br /><br />I agree. The RS-68 is the highest Isp first stage engine in existence (I consider the SSME a "core" stage engine.) This is achieved at some cost to the stage, as it is still built with isogrid integral stiffeners. <br /><br />First off, it obviously wasn't clear that I wasn't advocating a LOX/LH2 pressure-fed system...sorry 'bout that. Pressure-fed really only works well with high density propellants. Let's pretend for a moment that density isn't an issue for the following discussion.<br /><br />My current study is baselined right now for a 290psi chamber pressure, and a 350psi tank pressure, allowing 60psi of losses from the tank discharge to the business end of the injector. The LPOT discharge, I noticed last time I had Jenkin's 3 ed out, was 303psi, the requirement of the HPOT intake. I thought hmm...if the tank pressure of the ET were the 350psi of my current study,

 

[aftercolumbia]

"your statement about changing the oxidizer-to-fuel ratio closer to stoichiometric will result in a higher Isp is false."<br /><br />Sorry, you're right. The SSME is already well beyond the optimal Isp for its pressure, however, more generally I am right. I've crunched these in the AFAL (Air Force Specific Impulse Calculator; downloaded from www.dunnspace.com ) to find Isp optimum mixture ratios for various conditions (mostly for LOX/RP-1).<br /><br />IIRC, the Atlas sustainer engine suffered flow separation and still survived. The CLV plans to use an SSME for its second stage, that's why we have the vacuum start discussion.

 

[aftercolumbia]

"Some people object to capsules having a ballistic reentry instead of a controlled glide. The original plans for Gemini called for it to use a paraglider instead of a parachute and to land airplane style like the X-15 on skids. This approach was dropped because of time constraints. NASA needed Gemini to fly before Apollo. There is no reason why the paraglider system can't be looked into instead of parachutes for the CEV. It would give the advantages of a winged craft without the large weight and thermal protection disadvantages of a space plane approach. "<br /><br />Actually, the reason why the Gemini deployable paraglider was dropped was because the deployment mechanism didn't want to work in flight. They didn't have time to get it to work properly, but not everyone had faith that they could even with all the time in the world.

 

[dobbins]

The Air Force seems to have faith in it, it was part of their plans for the Gemini B that would have been used with the MOL.<br />

 

[kane007]

Gaetanomarano re your earlier and this post regards the STS + the personal parachutes.<br /><br />If you remember your first static line skydive from a light plane at 3,000 feet pulling 100 miles/hour you'll remember how much pressure was applied from the wind as you tried to climb out under the wing. All my following free falls were capped at about 12,000 feet, and everytime the plane slowed to almost a stall to guarentee our safe exit. Thats why the pilot also carries a chute.<br /><br />Now increase that 7 - 9 times and you'll see why skydivers never use comercial airliners to jump from - very high chance of being ripped apart. <br /><br />Now try and exit a malfunctioning space plane, tumbling through the upper atmosphere at hypersonic velocity.<br /><br />Jelly!

 

[gaetanomarano]

since both CEV and spaceplane don't exists, the comparison is between Shuttle and Apollo<br /><br />Shuttle:<br /><br />about 40 km from runway and 15 km high the Shuttle commanders takes control from landing computer while Shuttle fly at subsonic speed slowing down to land speed<br /><br />at this point of landing, the commander ALREADY know if the Shuttle can lands safe with the right trajectory, all controls working, no wings damage, etc.<br /><br />if someting don't works and a safe landing is impossible, the crew has 3-5 minutes to escape from Shuttle<br /><br />but the time available to escape may exceeds this figure because the commander may have some informations about integrity of the Shuttle BEFORE the last 40 km when Shuttle speed is mach 2.5<br /><br />I don't include the time of flying around alignment cilinders and the fact that Shuttle commander can slow very much it activating air-brakes and pulling up the Shuttle's nose<br /><br />if it can't land safely, the max time available for crew to escape the Shuttle (or a similar WINGED vehicle) may increase to 10 minutes or more!<br /><br />Apollo:<br /><br />on reentry, the Apollo capsule slows the speed to 300 kmh in the last 20 km from sea<br /><br />but the problem is that parachutes must be open only at 3000 mt. from sea, not before<br /><br />only when the crew (or the computer) try to open the parachutes (at 3 km from sea and 300 kmh speed) they know if it works well or not!!!!!<br /><br />if someting goes wrong, the crew of Apollo (or a similar UNWINGED capsule) has only 36 seconds (36 seconds!!!!!!!!!) to escape the capsule and can't increase this time with air-brakes or other maneuverings!<br /><br />consider also that the crew can't launch them with parachutes in the last seconds... so, the time available to save their life is much less than 36 seconds!<br /><br />in a capsule like CEV, with four-six astronauts and ONE door (to be open manually), probably the first launch will be made in time, but not the next three-five!

 

[dobbins]

Shuttle:<br />Lands in hundred thousand pieces scattered all over Texas and Louisiana, Crew dead.<br /><br />Apollo:<br />Lands in one piece in Pacific Ocean Crew alive.<br /><br />Shuttle:<br />Tank Explodes, vehicle breaks up, Crew dead.<br /><br />Apollo 13:<br />Tank Explodes, Vehicle dosen't breal up, Crew lives.<br />