Gemini: We can rebuild it, we have the technology

[rancamp]

Me:<br /> />>And IIRCC the allowed 'failure' rate for cargo chutes<br /> />>is less than 10% while manned chutes are less than<br /> />>1%." <br /><br />gunsandrockets:<br /> />Ahem. You are not helping the case for reusable<br /> />chutes.<br /><br />I seem to be, you had seemed unaware of a current market, infrastructure and inspection/maintenance/repacking industry for large parachutes. I informed you that there is in place such a system.<br /><br /> />Somehow I don't think the crew of the space capsule<br /> />would feel too comfortable knowing their reusable<br /> />chutes would have a failure rate of 10%! Even the<br /> />smaller manned chutes with a failure rate of 1% is<br /> />backed up with a reserve chute.<br /><br />Again you seem to be reading into my statement more than was given. Unmanned cargo chutes have a MAXIMUM failure rate allowed DURING inspection, (not use) of 10%, the same for manned chutes. If 10/1% of a lot number of parachutes fail inspection, then the whole lot is recalled and remanufactured.<br />The failure rate of parachutes is much less than 1% overall in ALL catagories.<br /><br />Your 'question' was on the inspection criteria IIRCC, not the failure rate in-use.<br /><br />Point of fact the military inspection/packing and use system has a 'use' fail rate of less than, (IIRCC from my last discussion of this) .01% for cargo chutes and less than .001% for manned chutes over the last 10 years. And THEY use each chute up to 100 times!<br /><br /> />A space capsule does not have a reserve chute<br /> />(though an Apollo style 3-chute system may have<br /> />reserve capacity such that one of the three chutes<br /> />could fail and the capsule still survive).<br /><br />Actually that was a primary reason for three chutes. Even one chute only was survivable on landing. But the chances of more than one parachute failing was pretty small.<br />I'd also point out that just because no capsule AS OF YET has had reserves does not in any way rule them out.

 

[rancamp]

At the risk of raising mrmorris' bloodpressure again <img src="/images/icons/blush.gif" />)<br /><br />I need to point out something that might not be obvious to the folks who might advocate something other than a 'simple' capsule.<br /><br />mrmorris is dealing with 'assumed' mass constraints for a proposed booster that hasn't flown yet. We're not at liberty to 'assume' a redesign of the booster soley on the the 'chance' that it might loft a lifting vehicile. Lifting bodies or winges require a vehicle to be strengthened and modified to allow for those lifting forces during take off. The Falcon V will NOT be so designed! We have to live with that. Wings would cut into our payload enough that with the Falcon V mass budget we most likely couldn't loft at 'least' 5 (five) people as required.<br /><br />A capsule makes the most sense. The only reason it's not 'usually' considered more often is because the general view has always been that capsules are one shot vehicles and there is no ACTUAL reason that this has to be true!<br />If anyone feels like 'argueing' the point, I highly suggest that they start 'another' thread with THIER vehicle idea and do as mrmorris has done and actually get down to the math of thier idea. I (and probably a lot of folks on this thread) would love to get in on that disscussion too. But this is NOT the place for it.<br /><br />Randy

 

[gofer]

Data point re: reserve chutes. The Souyz TMA has 2 parachute systems, main and backup. The two containers (open) are visible here http://www.russianspaceweb.com/soyuz_reentry_200.jpg , apparently they don't take that much of weight/volume (The Souyz design is also purpousfully minimalist)

 

[gunsandrockets]

Let's say an Apollo style three parachute system is used. Since the masses involved are in the same ballpark that makes sense.<br /><br />Let's say those chutes cost $10,000 apiece (a number you threw out). If they are thrown away after every flight, that's a $30,000 expense.<br /><br />Compare that to the cost of lifting mass to LEO. The uprated Falcon V with RL-10 engined upper stage is projected to cost $20 million per flight and lift 20,000 pounds to LEO. That is $1,000 per pound to LEO, an all time low.<br /><br />$30,000 for chutes. $1,000 per pound to LEO.<br /><br />Does it begin to sink in how unimportant the cost of the parachutes are? How pointless any cost savings from reusing them would be?

 

[gunsandrockets]

"Data point re: reserve chutes. The Souyz TMA has 2 parachute systems, main and backup. The two containers (open) are visible here http://www.russianspaceweb.com/soyuz_reentry_200.jpg , apparently they don't take that much of weight/volume"<br /><br />Interesting. I didn't know the Soyuz used a reserve system. Even so, it seems like it needs some work.<br /><br />"Soyuz 1 (24 April 1967): after launch, only one solar panel deployed, meaning that there was only 50% of the expected electrical power and also some of the control thrusters were blocked by the folded panel. Vladimir Komarov, the sole cosmonaut on board, was able to bring the spacecraft out of orbit after 26 hours, but the descent module was tumbling during re-entry, resulting in both the prime and back-up parachutes becoming entangled after deployment. The spacecraft crashed, killing Komarov: the first in-flight space fatality."<br /><br />You would think an emergency backup system would stabilize the capsule first before tossing out the chute. Perhaps that has been fixed since the Soyuz 1.<br /><br />Having a reserve parachute system as a design choice to increase safety can make sense depending on what tradeoffs must be made. But to include a reserve parachute system just to obviate increased risks from reusing the main parachutes is silly. Any costs saved from reusing the main parachutes would be overwhelmed by the increased costs of adding a backup parachute system.<br /><br /><br />

 

[gunsandrockets]

"Your 'question' was on the inspection criteria IIRCC, not the failure rate in-use."<br /><br />No it wasn't. How the hell do you get that when my question was 'what is the margin of safety?' <br /><br />"Point of fact the military inspection/packing and use system has a 'use' fail rate of less than, (IIRCC from my last discussion of this) .01% for cargo chutes and less than .001% for manned chutes over the last 10 years. And THEY use each chute up to 100 times!"<br /><br />At least now we are starting to get somewhere. Though you still don't give a comparative failure number between first use of a parachute, and that 100th reuse.<br /><br />Why don't you post a link to something authoritative. <br /><br />" I am ALSO not the one who didn't seem to know that parachutes are reused all the time "<br /><br />Oh please. Stop wasting my time and yours with all your strawman crap.

 

[gunsandrockets]

"I think the SRB parachutes are reused. "<br /><br />You are correct, and it's quite an involved operation too.<br /><br />http://www.answers.com/topic/space-shuttle-solid-rocket-booster<br /><br />The drogue chute detaches at 6,000 feet. After the SRB hits the water at 50 mph the three main chutes detach from the SRB. Each chute has it's own floatation device.<br /><br />http://www-pao.ksc.nasa.gov/kscpao/nasafact/ships.htm<br /><br />Then comes the retrieval ship which winches the chutes onto four drums.<br /><br />http://www-pao.ksc.nasa.gov/nasafact/prf.htm<br /><br />The chutes are delivered to the parachute refurbishment facility, where they are cleaned, repaired and repacked.<br /><br />"After the chutes are returned to the PRF following launch, a hanging monorail system is used to transport each parachute into a 30,000-gallon washer and then into a huge dryer heated with 140-degree air at 13,000 cubic feet per minute.<br /><br />Typically, each main canopy requires hundreds of repairs after each use. The smaller chutes and the parachute deployment bags they are packed in also require repairs.<br /><br />Multiple repairs typically are needed for several reasons. The chutes are deployed so quickly that their fabric, taping and lines can be damaged by friction burning. For example, each 136-foot diameter main canopy with its 204-foot-long series of risers, bridles and lines comes out of its bag in 1.5 seconds.<br /><br />Other sources of damage to the chutes are sea conditions and hot debris from the SRB nozzle extension jettison. In addition, the pilot parachute/drogue chute deployment bag assemblies are not always recovered, and when they can’t be, the team manufactures replacements."<br /><br />All in all it's quite an operation and I i

 

[gunsandrockets]

In the search for answers to exactly what Bigelow wants with his America's Space Prize competition, I have been calling Bigelow Aerospace. I now have some answers.<br /><br />My original confusion was due in part to stories such as this one which the Bigelow Aerospace website links to...<br /><br />http://spaceflightnow.com/news/n0409/27bigelow/<br /><br />"Company founder and millionaire Robert T. Bigelow told Aviation Week & Space Technology that he will announce as early as this week a new $50-million space launch contest called America's Space Prize." <br /><br />"The objective is to spur development of a low-cost commercial manned orbital vehicle capable of launching 5-7 astronauts at a time to Bigelow inflatable modules by the end of the decade." <br /><br />"America's Space Prize will be patterned somewhat after the X Prize that will go to the first team to demonstrate back-to-back suborbital flights." <br /><br />"America's Space Prize, however, is to award five times more money than the $10-million X Prize. And if successful, the winner of America's Prize would have developed something different - the first commercial manned orbital spacecraft - which unlike the X Prize, could be used for something other than just a spectacular ride." <br /><br />"The new contest also presents challenges far greater than the X Prize by requiring development of a vehicle that could maneuver to dock at well over 100 mi. altitude and survive a 17,500-mph. reentry." <br /><br />"America's Prize will be set up so the winner can propose launch on an existing (even non-U.S.) booster, depending upon the entrant's spacecraft configuration. "<br /><br />Which of course led me to think that the America's Space Prize was about developing just an orbital manned component of a spacecraft and not a launch vehicle. A notion reinforced by other sources such as this one...<br /><br />http://www.astronautix.</safety_wrapper

 

[mrmorris]

<font color="yellow">"The 20 percent equipment expendibility rule refers to the dry mass of the vehicle (no surprise there). "</font><br /><br />OK -- I created a post earlier in the thread with some calculations for this with the Falcon-V and G-X3. However, since this is continuing to be a hot topic, I'll work the calcs again. <br /><br />Since the Falcon-V still exists only on paper -- it's obvious I can't generate verifiable figures. However, last time I simply made estimates based on the specs for Falcon I and guesses as to the mass relationship between the first and second stages. This time I'll use stats from an existing booster to add some rationale to my voodoo math. Namely, I've mentioned before that the Titan-2 was very similar in size and performance to the Falcon-V specs. Using the mass numbers from it should make the calculations more solid:<br /><br />Titan 2:<br />- Both stages: Gross Mass: 146805<br />- Both stages: Dry Mass: 9140<br />- Mass fraction: 93.77 %<br /><br />- Stage Number: 1. Gross Mass: 117,866 kg. Empty Mass: 6,736 kg.<br />- Stage Number: 2. Gross Mass: 28,939 kg. Empty Mass: 2,404 kg. <br />- Stage 1 is 83.7% of the dry mass.<br /><br />Falcon V: <br />- Gross Mass (both stages): 181,400<br />- Dry mass (both stages): 10,884 kg (assuming a 94% mass fraction)<br /><br />Assuming the stage ratios are comparable to the Titan 2, we get:<br />- Stage 1 Empty Mass: 9110 kg<br />- Stage 2 Emty Mass: 1774 kg<br /><br />Earlier I worked out the DO SRMs required about 234 kg of propellant and the RCS required about 374kg (assuming LOX-Ethanol thrusters). G-X3's numbers then would be about:<br /><br />G-X3 Mass: ~5400 kg<br />G-X3 Dry mass: ~4792 kg<br /><br />Total dry mass: ~15676 kg<br />20% of dry mass: ~3135 kg. <br /><br />The second stage loss is a given, leaving us with a 1361 kg budget for expendable equipment on G-X3. This seems doable -- especially if the LES can have a secondary purpose -- such as the station orbit boost as I su

 

[rancamp]

I need to apologize to gunsandrockets. Given our criteria for the intial G-X3 vehicles he's actually correct.<br />I'll concede the point... but not the argument <img src="/images/icons/blush.gif" />)<br /><br />"I" was incorrect in my assumptions of parachute prices, which throws my whole argument out the window, (per se.. for higher flight rates, resuse STILL makes sense) since I didn't know the exact pricing for large chutes of the type we'd need.<br /><br />He asked for more 'authoratative' sources than my word. I can only say that most of my information came directly from the mouths of those who worked inspecting/maintaining/packing military parachutes. Since I have lost my contact in the local Egress shop I will attempt to contact the local parachute maintenance shop directly and find out what I can.<br /><br />AS for the parachutes, I found the following in an article on the web:<br />http://www.qmfound.com/air_bosnia.htm<br /><br />Which quotes a price for 64foot diameter multi-use chutes as $2,500 dollars.<br />"When the operation expanded, the demand for the 26-foot ring slot parachute surpassed the quantity on hand. After conducting several tests, a larger parachute, the G-12D, was used. This parachute, 64 feet in diameter, cost $2,500, roughly five times more than the 26-foot ring slot."<br /><br />So if a 100 foot chute costs "5 times" the price of a 64 foot shoot that comes out to only $12,500 dollars per chute.<br /><br />It also notes the time and personnel needed for packing the chutes, (which had been modified to open at higher speeds and altitudes)<br /><br />"The G-12D is a standard low-velocity parachute designed to drop heavier loads from a much lower altitude than what Operation Provide Promise airdrops required. To change this low-velocity parachute to a high-velocity one, the riggers had to modify the G-12D. This procedure adds about 10 minutes to the packing process. Instead of taking 1 soldier

 

[rancamp]

I realize we've already covered this but I'd had a thought... (ya again <img src="/images/icons/smile.gif" /><br /><br />Since we're begining to get to looking like the old BAE capsule design I noted something about them. Since we have to have the docking adapter anyway, (I know it would increase the mass in the nose even more) how about mounting the de-orbit/manuver rockets on the nose?<br /><br />

 

[rancamp]

Ok, how do I embed a picture?<br /><br />

 

[nacnud]

you can add a picture during the preview post process before you finaly post.<br />

 

[mrmorris]

<font color="yellow">"...how about mounting the de-orbit/manuver rockets on the nose?"</font><br /><br />I've considered it -- instead of having the expendable de-orbit/LES structure at the rear, have it attached at the nose. For LES operations this would provide inherent stability -- much like the Apollo/Mercury LES. <br /><br />My main problem with it is for docking. How exactly is this going to work with a DO/LES structure sticking on the nose of the craft (although I may be visualizing things differently than you)?

 

[gunsandrockets]

"Actually, the dry weight of the t-space carrier-plane should swamp the empty mass of the upper stages . "<br /><br />You are correct, I spoke too hastily. Since a modified 747 is being considered by t/Space as the airlaunch vehicle of it's Airlaunch rocket system, there are some hard numbers available for analysis. Empty weight of a 747 can run as high as 170 tonnes. Whereas the empty weight of a Titan II rocket including an empty Gemini spacecraft is only about 11.6 tonnes. Clearly there is a huge margin enabling the Airlaunch system to qualify under the 20% expendible equipment rule of the America's Space Prize (ASP) contest.<br /><br />Because of this margin and the low development risks of the Airlaunch Very Large Aircraft (VLA), t/Space has a design which could more easily satisfy the requirements of the ASP than Kistler or SpaceX.<br /><br />The only problem is t/Space is starting late. They claim they can have a system flying by 2008, but that is only if the Government will give them $400 million dollars. Reduced to private financing it would be very tight for t/Space to make it by the ASP deadline of January 2010.

 

[gunsandrockets]

" leaving us with a 1361 kg budget for expendable equipment on G-X3. "<br /><br />??<br /><br />I was wondering how you could come up with such a large margin for the G-X3 when my own brief calculations based on the Titan I and Titan II/Gemini numbers didn't come out anywhere near that good. So I took another look at your numbers and realized the problem.<br /><br />"Titan 2: <br />- Both stages: Gross Mass: 146805 <br />- Both stages: Dry Mass: 9140 <br />- Mass fraction: 93.77 %<br /><br /> - Stage Number: 1. Gross Mass: 117,866 kg. Empty Mass: 6,736 kg. <br />- Stage Number: 2. Gross Mass: 28,939 kg. Empty Mass: 2,404 kg. <br />- Stage 1 is 83.7% of the dry mass."<br /><br />Your math is off. Stage 1 is not 83% of the total dry mass, it is instead 73% of the total dry mass. Stage 2 is 27% of the total dry mass.<br /><br />Now throwing away 27% looks worse than it really is because there is another factor that needs to be added to the equation, a factor you left out, which is the dry mass of the Gemini Spacecraft. The numbers I found at astronautix.com weren't as complete as I would have liked so I estimated the dry weight of the Gemini Spacecraft at 2.5 tonnes. That gives a total dry mass of 11.6 tonnes instead of 9.14 tonnes.<br /><br />When you plug the numbers into the corrected equation you get these results for the Titan II/Gemini spacecraft...<br /><br />1st stage: 58% of total dry mass<br /><br />2nd stage: 20% of total dry mass<br /><br />Gemini spacecraft: 22% of total dry mass<br /><br />This is how I came to the conclusion that the FalconV rocket, which has a reusable 1st stage and an expendable 2nd stage, would need a space capsule as reusable as possible to meet the requirements of the ASP.<br /><br />Without hard information for the FalconV rocket, I agree that the Titan II is a good stand-in. We can only hope that the FalconV second stage does not exceed 20% of the total dry mass. But using the Titan II as an example, it is reasonable to expect the FalconV second stage

 

[mrmorris]

<font color="yellow">"Your math is off. Stage 1 is not 83% of the total dry mass, it is instead 73% of the total dry mass. Stage 2 is 27% of the total dry mass. "</font><br /><br />Ayup -- and I know exactly how I did it too. I actually used a calculator to figure percentage of the second stage (i.e. 27.3%), then decided I really wanted the percentage of e <b>first</b> stage. So I quickly subtracted 27.3 from 100. 10-2 is 8. 10-7 is 3. 1-.7 is 3. Bingo... 100-27.3 is 83.7! <img src="/images/icons/smile.gif" /><br /><br /><br />-- Whaddaya <b>mean</b> carry the one? Carry it where? I like it just fine where it is. <br /><br /><br />* On a side note. It <b>is</b> likely that the Falcon-V first stage will be a larger fraction of the dry mass than Titan's first stage becaise of the recovery aspects. Both the equipment for recovery and the fact that it's liable to be built with more a higher margin of structural integrity than the second stage will contribute to this. But of course we won't know until Elon builds it and lets us in on the specs... <img src="/images/icons/smile.gif" />

 

[ve7rkt]

<font color="yellow">It will be challenging to recover the more fragile structure of a liquid propellent booster intact.</font><br /><br />Magic 8-ball says, "ask again later." <img src="/images/icons/wink.gif" />

 

[gunsandrockets]

"On a side note. It is likely that the Falcon-V first stage will be a larger fraction of the dry mass than Titan's first stage becaise of the recovery aspects. Both the equipment for recovery and the fact that it's liable to be built with more a higher margin of structural integrity than the second stage will contribute to this. "<br /><br />Other factors to take into account of the mass distribution of the Falcon V are the lightweight lithium-aluminum alloy material the second stage is constructed of and the lightweight partially-pressure-stabilized/common-bulkhead design of the first stage. Taken all together the differences in the design between the Falcon V and the Titan II probably cancel each other out as far as differences in the proportions of the stages.<br /><br />There is another hard number to look at though. The uprated version of the Falcon V will use the RL-10 engine instead of the SpaceX Merlin engine in the second stage. This will increase the expected payload to LEO from 13,000 lbs. up to 20,000 lbs. I prefer to examine this version of the Falcon V for meeting the ASP.<br /><br />http://www.spacex.com/index.html?section=media&content=http%3A//www.spacex.com/media30.php<br /><br />A Falcon V second stage with the RL-10 is very similar to the Centaur upper stage already in widespread use. So I will from here on refer to the uprated Falcon V as the Falcon-Centaur. Here is a link from astronautix on the late model Centaur stage as used on the Atlas V launch vehicle...<br /><br />http://www.astronautix.com/stages/cenaurv1.htm<br /><br />If we use the Titan II proportion theory, the Falcon V second stage with a Merlin engine should have a gross mass of about 35 metric tons. The late model Centaur stage only has a gross mass of 23 metric tons. Ya gotta love LH

 

[gunsandrockets]

From the rules of the America's Space Prize<br /><br />http://bigelowaerospace.com/prize.html<br /><br /><br />Note this:<br /><br /> "4. The Spacecraft must dock or demonstrate its ability to dock with a Bigelow Aerospace inflatable space habitat and be capable of remaining on station for at least six (6) months;"<br /><br />Remain on station for at least six months! I think this is the main thing to focus on when it comes to the electric power source for an ASP winning design.<br /><br />Clearly the ASP rule mimicks the way the Soyuz is employed for ISS resupply missions. A Soyuz flies up to the ISS, docks and unloads crew and cargo, then remains docked for use as a potential escape vehicle until the next Soyuz arrives at the ISS months later.<br /><br />That means the power source on the vehicle must have persistance. It shouldn't run dry while sitting around for months. That's probably why the X-38 Crew Rescue Vehicle (CRV) was designed to operate on battery power. That's probably why the Soyuz, which has batteries and solar-power panels, works so well this way. Do fuel cells develop problems when sitting around for months? Perhaps the hydrogen fuel slowly leaks away? Can't have that.<br /><br />One other possible option to battery and solar power is betavoltaic batteries, a type of battery powered by beta-ray radiation.<br /><br />http://www.betavoltaic.com/<br /><br />But this type of battery may not be ready in time by the 2010 deadline of the America's Space Prize. It is something to watch for in the longer term as a potential replacement.<br /><br />Without betavoltaics I'm afraid the only practical option is conventional battery power perhaps in combination with solar power. <br /><br />

 

[gunsandrockets]

How difficult is it to design a fully reusable ASP Capsule?<br /><br />Even though I just spent a whole post describing how the Falcon-Centaur launch vehicle might have mass margin to spare thereby permitting a capsule to have some expendable equipment, it's not safe to count on that for real. That margin of 1 metric ton of expendable equipment could quickly disappear with the slightest of setbacks. Maybe the Falcon first stage will need beefing up to survive recovery enough for reuse. Maybe unanticipated weight growth or engine troubles will reduce the Falcon's payload. And will the Falcon-Centaur version even be available in time? Falcon I and Falcon V are already behind schedule.<br /><br />Even assuming the best of outcomes a Falcon-Centaur launched ASP Capsule would need almost complete reusability, 4.9 tonnes reused out of 5.9 tonnes dry mass. So it's prudent to design the capsule with the minimum amount of expendable equipment. So as a starting point let's see if a completely reusable configuration is even possible.<br /><br />Aside from the obvious things the ASP Capsule must have, such as room for five, docking capability etc., two of the biggest headaches for a completely reusable design are the launch escape system (LES) and the orbital manuevering system (OMS). Unlike a conventional fully expendable capsule which can toss away all the inconveniently sized pieces as it needs to, a fully reusable capsule has to hang onto every piece for the whole flight. Despite the vast differences in size and shape a fully reusable capsule will have much in common with the reusable Space Shuttle Orbiter.<br /><br /> For efficiency even a relatively small OMS rocket needs a generously sized expansion nozzle. How do you fit that large bell nozzle into a capsule where it won't get in the way of launch ascent or orbital reentry? And the Apollo rocket tower LES was really massive. The Apollo LES had as one of it's parts a launch shroud which protected the Apollo Command

 

[rancamp]

mrmorris wrote:<br /> />My main problem with it is for docking. How exactly is<br /> />this going to work with a DO/LES structure sticking on<br /> />the nose of the craft (although I may be visualizing<br /> />things differently than you)?<br /><br />If this works...<br /><br />

 

[rancamp]

Another consideration though.... If I understand correctly the 'reuse' of the Falcon 1 first stage will be more like 'salvage' how will this compare to the Falcon V?<br /><br />Randy

 

[mrmorris]

<font color="orange">"(although I may be visualizing things differently than you)?"</font><br /><br /><font color="yellow">"If this works... "</font><br /><br />I was indeed visualizing things differently than you -- at least inasmuch as what I visualized didn't look anything like <b>that</b>. Unfortunately -- the diagram doesn't do much for me in terms of figuring out what you're thinking, or where docking takes place, etc.

 

[mrmorris]

<font color="yellow">"...the 'reuse' of the Falcon 1 first stage will be more like 'salvage' how will this compare to the Falcon V?"</font><br /><br />HeckifIknow. I don't really sweat the design of the Falcon-V as much as you and G&R. I'm having fun designing the capsule -- the booster is Elon's job... <img src="/images/icons/smile.gif" /><br /><br />I have enough trouble keeping my imaginary capsule design specs in hand without worrying about the exact operational procedures of the paper booster I plan to fly it on. I'm working to get as much <b>real</b> hardware and <b>real</b> construction details into the G-X3 design as possible, but I don't ever really get confused into thinking that it's really real.