Gemini: We can rebuild it, we have the technology

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mrmorris

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<font color="yellow">"...and ended up here."</font><br /><br />Welcome to SDC. Sorry about the dreams. However, while I am American -- I'm not a multimillionaire -- so I won't be competing for the prize either...<br /><br /><font color="yellow">"...if the capsule ends up wider than the Falcon V"</font><br /><br />It doesn't look like that'll be an issue. Twelve feet should be ample diameter for the craft.<br /><br /><font color="yellow">"...if the Falcon V doesn't cut it, it's off"</font><br /><br />I've wondered what Bigelow meant by the 20% forever (i.e. was the launch vehicle included in that). Didn't think to re-check the rules after they finally got posted at the updated BA website. At any rate -- given an actual definition -- we can calculate this. Obviously the rules mean dry mass. <br /><br />Working from the SpaceX website: the mass of the Falcon V is 181,400 kg and they indicate on the Sept/Sug 2004 archive they are meeting a targeted 94% mass fraction for the first stage on Falcon I. We'll assume the same target for the V. The second stage *should* be even higher, as there's no recovery equipment, but we'll leave it the same. This would give a total structure mass of 10,884 kg. Figure 80% of that mass is the first stage. This leaves us with ~2177 kg of dry weight in the second stage that's lost each flight. So the mass fraction that is lost would be approximately:<br /><br />2177 / ( ~10,884 kg (F-V) + ~5,500 kg (G-X3) ) = ~13.28 %<br /><br />This should be doable then. There's a little over 1000 kg of expendable mass to 'spare' before the 20% rule kicks G-X3 out of the running.<br /><br /><font color="yellow">"But where would you store and attach the parachutes? "</font><br /><br />I've pretty well switched to the Apollo shape, as the thread evolution shows. In that -- there's a 'triangular ring' (weird concept, but the only name I can think of for the shape) of volume around the docking tunnel which is where the

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ve7rkt

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<blockquote><font class="small">In reply to:</font><hr /><p> There's a little over 1000 kg of expendable mass to 'spare' before the 20% rule kicks G-X3 out of the running. <p><hr /></p></p></blockquote><br />Okay... so the ablative on the TPS, and the parachutes (I assume they're one-shots), and the dry mass of the deorbit module must all add up to about a ton. A 1/2 ton frame, just long enough to house the deorbit motors, that supports roughly 25 tons (5 ton capsule * 5G)? Seems appropriate. Cool.<br /><br />(Additional Revenue Source: sell backpacks, keyrings, laptop bags, etc. made from the parachutes of the first commercial orbital flight. Hey, they sell bags etc. made from Soyuz 'chutes, and those are "just" station missions, TM-8 to Mir and TMA-3 to ISS )<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p> switched to the Apollo shape, as the thread evolution shows. In that -- there's a 'triangular ring' <p><hr /></p></p></blockquote><br />Right... I did catch that the design was more Apollo-esque now, but I didn't know it had that space there.<br /><br />Another thought... do I understand correctly that the GX3 would have RCS and deorbit motors, but the role of OMS to match orbit with the station would be handled by the launch vehicle's upper stage? I assume the FalconV upper stage has a method for deorbiting itself, whether that means a separate deorbit package, a "terminator tether," or conserving enough fuel to restart its main engine. Otherwise, not only would the craft be leaving garbage in LEO, it'd be a large chunk of garbage in almost exactly the same orbit as the station, which could really suck a few orbits later! FalconI performs a "collision avoidance maneuver" to keep it from impacting the satellite it launches, but it sounds to me like it ends up staying in orbit. Our launcher ripping hol

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mrmorris

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<font color="yellow">"... do I understand correctly that the GX3 would have RCS and deorbit motors, but the role of OMS to match orbit with the station would be handled by the launch vehicle's upper stage? I assume the FalconV upper stage has a method for deorbiting itself..."</font><br /><br />Here we get into a problem with me having Not-Enough-Data (the booster exists only on a website and, presumably, a CAD file somewhere). I mentioned at one point that the F-V is supposed to have rendevous/docking capabilities by 2008 according to Shotwell of SpaceX. This gives us essentially four possibilities for where the separation of G-X3 and the second stage occurs:<br /><br />1. SS takes G-X3 to 200km, separates and either performs a short DO burn or simply allows the orbit to decay (I forget the timeframe of a 200km orbit... but it's not long). G-X3 then would need to have sufficient RCS/OMS capability to lift its orbit from ~200km to ~400km, approach the station, dock, undock, perform a DO burn, and use RCS for controlled re-entry.<br /><br />2. SS takes G-X3 to ~400km, separates and performs a DO burn to re-enter. G-X3 then would need to have sufficient RCS/OMS capability to approach the station, dock, undock, perform a DO burn, and use RCS for controlled re-entry.<br /><br />3. SS takes G-X3 to ~400km, approaches and docks with the station, then separates and performs a DO burn to re-enter. G-X3 then would need to have sufficient RCS/OMS capability to undock, perform a DO burn, and use RCS for controlled re-entry.<br /><br />4. SS takes G-X3 to ~400km, approaches and docks with the station, undock, perform a DO burn, then separate. G-X3 then would need only to have sufficient RCS for controlled re-entry.<br /><br />Obviously, the more cpability given to the second stage, the less that needs to be in G-X3. There are tradeoffs for all of the options, and I don't really have a means of determining which is optimal -- there are simply too many variables. A lar

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ve7rkt

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Aaaah. I'd never thought of docking to the station with the second statge still attached, I had option #2 stuck in my head.<br /><br />Any further questions along those lines will probably have to wait for the Falcon V Payload Guide, I guess.

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mrmorris

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<font color="yellow">"...docking to the station with the second statge still attached..."</font><br /><br />It was never my initial plan either. When the thread started -- I simply assumed option 1. However, with the Falcon V able to lift the G-X3 to higher orbits than 200km at the masses I was calculating, I thought of options 2 & 3. Finally, since the Apollo CM was meant to have the Service Module provide essentially all of the orbital maneuvering -- I had to consider the second stage of F-V acting essentially as a quasi-service module (the propulsion aspect of it anyway) and came up with option 4.

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mrmorris

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I noticed on the launch of DART today that the Pegasus actually uses the SIGI for its avionics. They didn't give a manufacturer, but presumably this would be the SIGI made by Honeywell that is the precursor to the E-SIGI I suggested as G-X3's avionics/guidance system. This is good news, as I've been worried about the price of the E-SIGI. Honeywell doesn't exactly give dollar figures on their site, so for all I knew, the E-SIGI was a \$10M piece of equipment. However -- given the price for a Pegasus launch, this is demonstrably not the case.<br /><br />Orbital offered a breakdown of a small launcher's price at this site.<br /><br /><b>Components of a Small Launcher’s Price<br /><br />Item -- % of Launch Price</b><br />---------------------------------------------------<br />25.7% - Propulsion<br />25.0% - Mission Support Labor<br />21.4% - Amortization of DD&E<br /> 8.6% - Assembly Labor<br /> 8.6% - Avionics<br /> 7.1% - Flight Termination System and Range<br /> 4.3% - Structures<br /><br />From this, at \$20M for a Pegasus flight, we can assume the SIGI costs no more than \$1.72M. This would assume both that it's the **only** component of the Avionics cost. Using the full \$20 million as the starting value would also mean that Orbital isn't making a profit from the flight since the breakout doesn't include a profit, and the number sum to 100% (actually 100.7% -- I assume rounding issues). Since it's fairly safe to say that neither of those is the case -- I'd guestimate the cost of the SIGI at under a million. How much under is indeterminate without more data.

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rancamp

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Speaking of various launch costs and such, have you seen this recent paper:<br /><http://www.transterrestrial.com/uploads/PHYSICS-AND-ECONOMICS-OF-LEO-ACCESS.doc /><br />(MS Word format)<br /><br />While it doesn't take into account several factors of Space-Xs launches, (Hobbyspace has some numbers from Space-X and they don't look quite so bad) it's an interesting read.<br /><br />The Space Review has an article on it also. (Considering one of the papers authors is a regular there <img src="/images/icons/blush.gif" />)<br /><http://www.thespacereview.com/article/233/1 /><br /><br />Randy

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aaron38

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For docking options 3 & 4, wouldn't bringing along the extra SS mass to docking cost the system a lot of efficiency? It'll take a lot more fuel to do the delta V docking manuvers with the SS attached.<br /><br />I would think that option 2 would be more efficient, at least from a fuel standpoint.

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mrmorris

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<font color="yellow">"Speaking of various launch costs..."</font><br /><br />Yep -- I've read it. I'm focusing on the vehicle, though, not the launch system. I hope that Elon can change the paradigm. He's working on several of the 'problem areas' (small launch crew, small assembly team, cheaper launch fees (Marshall Islands). We'll see how well that works in a year or three... hopefully.

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mrmorris

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<font color="yellow">"...the extra SS mass to docking cost the system a lot of efficiency"</font><br /><br />ANytime you have more structural mass, maneuvers will take a larger amount of propellant. However, the docking isn't a high dv maneuver. The (orbital) maneuvers which will cost a lot of dv are the rendezvous burn (200-400km), and the de-orbit burn. <br /><br />- If the second stage is dropped before the rendezvous burn (option 1), then it need only have sufficient propellant to get G-X3 to 200km, because it can simply separate and allow its orbit to decay. This would be the <b>most efficient</b> use of propellant -- essentially giving the launch system a third stage. However, GX-3's RCS/OMS must then be very capable. G-X3 must be larger and heavier, imposing more stress on the re-entry system. On the other hand -- it potentially increases the mass fraction of G-X3 which is re-usable.<br /><br />For anything after that option, the second stage has already reached 400km. This means that it has to have sufficient propellant for a DO burn to avoid becoming dangerous debris. If *it* has to have sufficient propellant to perform a DO burn for its own mass, and G-X3 has to have sufficient propellant to de-orbit <b>its</b> mass, then you're not really seeing any gain in efficiency by separating them before their respective DO burn(s).

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mrmorris

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Well the failure of DART is a real downer. I'd hoped that was going to be the presursor of the technology for the automated docking of G-X3. There's still the XS-11, I suppose, but it's unlikely the Air Force will parcel out that tech to private firms.<br /><br />If G-X3 is going to have autonomous docking capability -- it will likely have to come from somewhere else. Possibly the Russians will sell KURS tech or ESA will license their tech for the ATV. Alternately, SpaceX (or whoever) might try to develop it from scratch, but this is a tall order given the timeframe and other demands on development resources. Hobbyspace mentioned a couple of university led projects in autonomous spacecraft maneuvering. The more interesting of the two was Bandit. However -- not only hasn't it flown, but there's a wide gap between what it is targeted to be capable of and what G-X3 needs. Probably best to try for KURS or the ESA equivalent at this point.

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ve7rkt

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Does G-X3 *need* autonomous docking? It'd be nice five years later if we build an unmanned cargo ship, Progress-style, but the G-X3 prototype and surface-orbit-surface crew ferry will always be manned, and a human makes a pretty fair though not unfailing guidance system. The human is also cheaper in terms of mass and equipment since he's there anyhow. More than one site cites that the reason why the Russians were trying a remote-control docking system for Progress M34 to Mir was that they couldn't afford the cost of the Ukrainian-made automatic system. I admit, though, I'm taking it on faith that the G-X3 pilots will do a better job... Progress M34 was the one that collided with Mir.<br /><br />Now, an automated re-entry and landing system, that's another matter entirely. Autopilot that sucker. Set it up so for an emergency evacuation scenario, the computer plots the next n-2 orbits where n is the orbit when the batteries run out, picks the one that gets it closest to one of a few select recovery zones, starts the countdown to deorbit burn, sends the results to mission control so they can charter the pickup helicopter, and prepares itself to administer the RCS rolls for fine-tuning the descent.

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mrmorris

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<font color="yellow">"Does G-X3 *need* autonomous docking? "</font><br /><br />I would say 'Yes' in the long run. In the short run -- no -- it's certainly not critical for S/N 0001. However, one of the means to reduce expenses is to reduce the level of flight/mission training required for your pilots. While there will always need to be a human-in-the-loop backup, an automated system would be a considerably more optimal solution.

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ve7rkt

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If you have human-in-the-loop as a backup, it means your pilot has to go through the manual docking training anyhow, right? It might seem less important, it might be less likely to actually be used, but the pilot still has to be skilled at it in case he does need to take over.<br /><br />But as mentioned before, G-X3 can evolve. Just like we don't have to be stuck with one battery system, we don't have to be stuck with manual docking. It's okay to leave it for G-X3 Block II, or the s/n 1000 series, or whatever.<br /><br />New thought: if you've got the docking hatch on the pointy end, does it need some kind of fairing to protect it during launch? And does it need something to protect it during re-entry? I know it's on the 'cold' end, but still...

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mrmorris

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<font color="yellow">"...as a backup, it means your pilot has to go through the manual docking training anyhow..."</font><br /><br />There's a big difference between the readiness/training levels required. If manual docking is the only solution, then the pilot <b>must</b> be 100% ready to perform the operation... or the flight is a failure. If an automated docking system is available, and it is WAG 95% reliable, then there's a 1-in-20 chance of the mission being unable to dock with the station even if the pilot can't perform a manual docking. If the pilot had a 50% chance of being able to perform a manual docking maneuver (hopefully better than that... but hypothetically), then the chances of a docking problem causing a mission failure drop to 1-in-40. Anyway -- as indicated -- automated docking is an important technology for G-X3, but not a showstopper.<br /><br /><font color="yellow">"...does it need some kind of fairing to protect it during launch? And does it need something to protect it during re-entry..."</font><br /><br />On launch it will require a fairing. There should be no need for elaborate heat-protection on re-entry. The heat has dropped *way* off at that end.

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rancamp

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mrmorris:<br /> />Yep -- I've read it.<br /><br />I was wondering if you'd seen the 'follow-ups' by Space-X?<br />Elon Musk mentioned some figures for launch costs out of Vandenburg:<br />5.9million Base Fee<br />+ \$600K range fee<br />+ \$200k for third party insurance costs for non-goverment users.<br /><br />The Marshells Islands may have lower range fees, (depends on what is 'required') but has higher logistics costs associated with it.<br />HobbySpace:RLV news has some breakdowns of insurance costs and an explenation of what each 'party' insurance is.<br /> />http://www.hobbyspace.com/Links/RLVNews.html&lt;<br />(April 19th entry)<br />"First party insurance covers the loss of a vehicle. This obviously isn't very relevant to expendables but reusable vehicles will need such coverage.<br /><br /><br />Second party insurance covers the loss of a payload. It is typically obtained by the payload owner and not included in the launch price. The big comsat operators, for example, pay 10%-20% of the value of their spacecraft to obtain coverage both for the launch and for the estimated operating lifetime of the spacecraft. <br /><br />If you were launching bulk cargo to the ISS or fuel to an orbiting depot, you probably would not get payload insurance.<br /><br />Coverage for passengers comes under the second party insurance category.<br /><br /><br />Third party insurance covers damages if the rocket crashes onto property or people outside of the launch site. E.g. Mr. Musk says third party insurance will cost Falcon I customers about \$200k. <br />It turns out that the price of third party insurance doesn't increase very much with the size of the vehicle. Essentially, insurers are saying that the probability of maxing out the insurance claim if a rocket falls on or near a bus or cruise ship isn't sensitive to vehicle size.<br /><br />This means that small vehicles are penalized by third party insurance costs. Combining several small payloads onto a larger vehicle would substantially reduce the c

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najab

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Third party insurance for a new rocket is next to impossible to get. The US Government used to offer up to \$1 billion in liability coverage for US registered launch companies, but I don't think they do this any more.

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mrmorris

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Thanks for the *bump* -- but I won't let this thread get <b>too</b> low... <img src="/images/icons/smile.gif" />. It's just taking me longer to find new items of interest. I've already found hardware capable of filling most of my subsystems so I have to find a better/cheaper fit before I post new data. Those subsystems which I *haven't* filled with an existing piece of hardware are ones for which it's going to be difficult/impossible to find. I seriously doubt that I'll locate an OTS ECLSS system (certainly not one sized for G-X3, I've already found and posted the links to the shuttle's ECLSS equipment at Hamilton-Sunstrand).<br /><br />The most interesting thing I found recently was more a matter of a hint of possible equipment than equipment itself. The 'Careers' link on Bigelow's site has several job postings with interesting implications:<br /><br />- Propulsion Systems <br />- Power Systems <br />- Attitude Determination & Control Systems <br />- Command, Control & Communication Systems <br />- Docking Systems <br /><br />The first four imply that Bigelow is developing his own Command, Control and Propulsion module. I'd read somewhere that he would likely be purchasing a Zarya from the russians for this purpose. Since they actually have a spare one -- I'd really figured that was nearly a sure thing. If he's actually developing this himself -- it has significant implications for G-X3. For one thing -- it may very well be possible to license/buy some of the tech he's developing. With his methodologies -- this may very well be the cheapest means to secure critical technologies for G-X3.<br /><br />The job posting for somebody proficient with Docking Systems is further evidence to me that Bigelow is developing his own docking system -- presumably LIDS or a derivative thereof. Again -- this has the potential to simplify the development requirements of G-X3 and reduce the cost.

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mrmorris

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There's an interesting article (not a new one) at Spaceref.com about the potential of using Apollo command modules as the ISS Crew Return Vehicle (CRV) and as a CTV (Crew Transfer Vehicle... I think). They bring up several interesting points, although their analysis doesn't go in-depth into any one area. In particular -- they didn't do much investigation of existing electronics. Their blanket statement regarding Guidance/Navigation/Control/Displays was:<br /><br /><i>"Entirely new electronic systems and displays will be required. Triplex digital flight controls and a redundant integrated GPS/laser inertial navigation system, along with new avionics interfaces will have to be developed. Radiation hardened computers should be examined for use. "</i><br /><br />It's obvious from the article that they didn't locate modern equivalents and do a volume/power/mass analysis and seen just how much of a difference this makes to the viability of the design.<br /><br />I don't like their de-orbit system. They're proposing hypergolics. I think solids makes much more sense for this.<br /><br />It's very obvious they didn't do much research for the communications system:<br /><br /><i>"Standard communications and telemetry adapted from the STS can be used, including TDRSS interfaces, uplink, S-band and UHF systems. Because of weight, power, and volume, packaging challenges are expected for the basic CRV, the instrumentation list must be constrained to safety for flight for the CRV. "</i><br /><br />The LPT is tiny, uses very little power, and provides everything on that list except UHF.

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ve7rkt

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<font color="yellow">The first four imply that Bigelow is developing his own Command, Control and Propulsion module. I'd read somewhere that he would likely be purchasing a Zarya from the russians for this purpose.</font><br /><br />Several of the CGI images on the website show what I *think* is a Zvezda. The ISS' Zvezda was itself a backup for Mir's, and NASA was working on a backup service module in case Zvezda's launch failed, so I don't believe there is another Zvezda already built. BUT, they've got a few pictures that use the Unity module, with Soyuzes docked to the module berthing ports, so the images may not be the most reliable version of Bigelow's plans. <img src="/images/icons/wink.gif" /><br /><br />When I saw the list of jobs for hire, I considered ditching my Cognitive Science degree, walking down to the polytechnic school, and signing up for the CNC Machinist program. <img src="/images/icons/laugh.gif" /><br /><br />For an OTS ECLSS system -- we're really just looking for air, right, we're still going with diapers? -- how about the systems designed for luxury & research submarines? US Submarines, for example, sells a submarine called the [link=http://[url=http://www.ussubs.com/submarines/discovery_1000.php3]www.ussubs.com/submarines/discovery_1000.php3[/url]] Discovery 1000 [/link], with a life support system that sustains 4 people for up to 96 hours (24h primary, 72h reserve). Doesn't help with temperature management, because you don't have a nice big ocean for a heatsink, but it's a starting place.

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mrmorris

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<font color="yellow">"...I don't believe there is another Zvezda already built..."</font><br /><br />Dunno what's pictured on his site -- I wouldn't be able to distinguish Zvezda from Zarya by sight anyway. At any rate -- I said Zarya in my post, and that's the module I meant (albeit I <b>have</b> been known to confuse the two). Zvezda is the service module -- basically living quarters and ECLSS. Essentially it's equivalent to Bigelow's inflatables -- <b>they</b> act as Zvezda modules. Zarya is the command and control module and provides services that the expandables really aren't designed for. Here's a link regarding the second Zarya -- FGB-2.<br /><br /><font color="yellow">"...we're really just looking for air, right..."</font><br /><br />ECLSS includes O2 replenishment and removal of CO2, odors, airborne particles and moisture, as well as temperature control, and lighting. <br /><br />- Lighting will be done by LEDs. <br />- O2 replenishment will be bottled oxygen. <br />- CO2 removal will be done by LiOH cannisters.<br />- Odors will be mitigated by activated carbon filters.<br />- Airborne particles will be removed by a fan trap.<br />- Temperature control will be a combination of a glycol loop and loop heat pipes -- probably using a flash evaporator as a coolant.<br /><br />All of this I can tell you from research -- I could even draw a fairly decent diagram of an air handling system incorporating the bottom five items. I just can't find a website with a nifty PDF spec sheet like I have for several of the other subsystems. I like nifty PDF files -- they make my delusional spaceship seem slightly less delusional.

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