Gemini: We can rebuild it, we have the technology

[mrmorris]

<font color="yellow">"They are referring to the nose as the apex of the heatshield - the stagnation point."</font><br /><br />s'possible -- the text doesn't really define what they mean by the 'nose'. My own prejudices incline me to think of that as the 'back' of the craft (as do yours -- as your original reply objects to the cg in 'the nose' <img src="/images/icons/smile.gif" /> ). After all -- in every capsule design I can think of, the astronauts are facing the other direction. I would have thought they'd state 'the nose of the heat shield' instead of 'the nose of the vehicles', but then these are engineers, rather than English majors. <img src="/images/icons/smile.gif" />

 

[quikely]

I believe they thought of the nose as "the end facing the flow". Makes sense, I guess, but could have been more clear.

 

[scottb50]

Sounds like badmitten to me. Put a weight on the nose and it flies nose first. If you left lunar orbit for Earth gravity would have it re-enter head first. With a lower CG the pointy end would be up, a definite advantage. I think the Gemini CG was a lot farther forward because it was to have used a parfoil and had the big hatches. <div class="Discussion_UserSignature"> </div>

 

[couvillion]

""I think you have this backwards...""<br />I simply meant that Soyuz was smaller than Apollo.<br /><br />"My question is -- what is magical about a CBM-sized bulkhead. What is the benefit to the craft of having such a thing?"<br /><br />It appears that CBM will be the standard building block of the future. A pressure vessel containing both a CBM and APAS could be used as a basis for a docking port on a station, or airlock .And as a resupply vessel without a APAS.It should allow the saving of money compared to producing one off modules for such uses. <br /><br /><br />

 

[mrmorris]

OK -- pulling up the diagrams referenced in the patent where they are talking about the cg and the 'nose of the craft' -- it does appears that they're referring to the 'nose' of the heat shield.<br /><br />While we know that the shape of the original Gemini capsule <b>is</b> viable for a re-entry vessel, it's always a good idea to work for an optimal solution. In addition, the addition of the APAS-89 to the front of the Gemini capsule has already required a bit of redesign in the shape and will push the center of gravity further towards (can't call it the 'nose') the 'pointy-end' (BTW -- henceforth -- I think I'll just refer to cg location as 'closer to' or 'further from' the heat shield). <br /><br />In my original design diagram posted about midway back through the thread, I was trying to keep the exterior dimensions *exactly* the same as the original Gemini. Essentially I wanted to see if all of the equipment and electronics for the G-X3 mission, plus a crew of six could fit within that volume. I've spoken of (but not posted) a more recent design I've been working on that alters the dimensions to accomodate the APAS-89, and also makes better use of the available volume. I expanded the pressure vessel to the sides, reduced the crew to five, and changed from three rows of two seats to one of two seats and a second row of three seats. The interior dynamics of the craft became much less prone to crew conversations consisting of some variant of: 'Get your elbow out of my nose!'. The resulting craft was shorter, and had marginally changed exterior dimensions, but still started from the same maximum base diameter of as the original Gemini (10 feet). <br /><br />What I'm looking at doing at this point is expanding on this theme -- widening the base of the capsule and reducing the length. This will actually have the effect of making the capsule look more like the illegitimate offspring of Gemini and Apollo. It will have a couple of beneficial effects to the capsule

 

[nacnud]

The more the development of this goes on the more (to my eyes) it seems to resemble the BAe Multi-Role Recovery Capsule. I’m sure you have mentioned it before but perhaps it might be worth hunting down the reference given in the article: <br /><br />Hempsell, C M and Hannigan, R J, <i>Journal of the British Interplanetary Society</i>, "Multi-Role Capsule System Description", 1989, Volume 42, page 67.<br /><br />This would also be perfect for a CEV CTV as well as a base for a European capsule.<br />

 

[mrmorris]

<font color="yellow">"...perhaps it might be worth hunting down the reference given in the article..."</font><br /><br />I spent a good bit of time Googling for more information on that capsule, without a bit of luck (beyond the Astronautix info, of course). I admit that I haven't actually physically visited a library looking for data on it.

 

[najab]

12 foot diameter sounds good. You're right about it starting to look like the lovechild of Apollo and Gemini!!!

 

[mrmorris]

<font color="yellow">"...starting to look like the lovechild of Apollo and Gemini"</font><br /><br />Yep. Well I initially dismissed Apollo entirely as being too heavy. However -- I've done a bit more checking, and much of it can be discounted in a mix and match of the two concepts. The Service Module was the real bear. The Command Module itself was ~5,800 kg. While this is almost 2,000 kg heavier than the entire Gemini menage a trois -- it has a correspondingly larger targets for mass reduction. <br /><br />Applying similar weight reductions for the Apollo CM that I did to Gemini shows a reduction to about 3,900 kg (fast & dirty, but conservative). I think a more detailed analysis would turn up another 500-700 kg in reductions. I need to do some work on the structure of the Apollo CM to see what additional space is opened up by modern (smaller) components, and equipment eliminations from the more modest mission requirements.<br /><br />Onto the back of an Apollo-shaped CM, we'd then put the same de-orbit boosters and LES system specced out for G-X3. I'll have to do considerably more research to figure out the feasibility and get better mass numbers. I know much more about the Gemini hardware than I do about Apollo.

 

[mrmorris]

<br />Just played a bit with the specs from the Apollo Familiarization Manual. Looks like the basic Apollo capsule could easily accomodate five people. I know a 'sardine can' version was designed for Skylab rescue in the 70's so it was definitely <b>possible</b>, but with advances in electronics, etc. -- should now be doable without having to cram the passengers in with a shoehorn. The diagram below shows the original 3-person locations and an updated 5-person one. I've considerably reduced the size of the left and right-hand equipment bays, but left the lower equipment bay unchanged. I also reduced the size of the Display & Control panel at the front (a 'glass cockpit' using LCDs will likely be even smaller than what I've used). In addition, the icons used in the original doc were for suited astronauts. G-X3 is a shirt-sleeve environment, so there should be more room than what is shown.<br /><br />

 

[mrmorris]

I <b>love</b> declassified NASA documentation of studies run in the 60's. Turns out there's one that's done a whole heckuva lot of the work on speccing out Apollo as a 6 person craft for resupplying space stations. Cool things they studied:<br /><br />- Adding Gemini-style SRM retros for de-orbit.<br />- Adding capsule-level impact attenuation (shock absorbers) to reduce landing Gs.<br />- Adding landing retros to reduce landing impact G's.<br />- Using four parachutes instead of three.<br />- Reduced ablative/equipment mass from lunar mission reqs.<br /><br />Their weight summary (in pounds) from that study, plus my guesstimates (similar to above) for reducing it from the use of modern tech:<br /><br />Structure 2396 2396<br />TPS (full capsule) 1598 1100<br />Crew Systems 2104 1753<br />Comm & Instr 434 80<br />Guidance & Navig 282 60<br />Stab & Control 220 220<br />Reaction Control 593 593<br />Electrical Power 480 100<br />ECS 539 539<br />Landing 753 588<br />Docking 195 300<br />Controls & Displays 160 30<br /> <br />Structure for R&B 100 100<br />Re-entry Retro 936 936<br />Retro Batteries 232 50<br /> 11022 8845<br /><br />Some cool images from the doc follow -- I'll talk more on it and how modern tech can solve some of the problems brought up in the study in a future post.

 

[rancamp]

mrmorris:<br /> />I love declassified NASA documentation of studies<br /> />run in the 60's.<br /><br />Me too, got a URL for the docs your using?<br /><br />I'm actually more 'comfortable' with the Apollo CM design, truth be told. It's a much more 'stable' landing configeration IMHO. I seem to recall once seeing an illustration of a varient Apollo CMs up to and including an 8 person version, but no details such as you've found. Good work <img src="/images/icons/blush.gif" />)<br /><br />Randy

 

[mrmorris]

<font color="yellow">"...got a URL for the docs..."</font><br /><br />I've dug up things at multiple locations, incuding NASA's technical reports server, but the site I get most of my docs from (for both Gemini and Apollo) is here.

 

[mhcecire]

why dont you put together a tangible proposal and email it to jeff bezos or burt rutan? maybe some other rich guy so you can win this america's space prize?

 

[mrmorris]

<font color="yellow">"...so you can win this america's space prize? "</font><br /><br />There's a world of difference between what I'm doing and what would be required to actually *build* this craft. There's enough people out in the world today attempting to build spaceships in their garage. I'm perfectly happy to design a virtual one within the confines of this forum. I'm enjoying the process and spending no one's money.<br /><br />In any event -- Jeff is apparently planning for a very measured track -- starting with sub-orbital flights, and Rutan seems uninterested in spacecraft where there are no wings involved. I still say Elon is the best bet -- bith for the prize itself and for a spacecraft resembling G-X3.

 

[mrmorris]

In the Apollo logistics document -- adding the 'back row' of seats obviously cut in on the craft's safety margins for landing shock. The second row of seats eliminated the 'recoil' space behind the crew couches, forcing them to simply exchange a rigid strut where the X-axis impact attenuator was in the lunar Apollo. This is the primary reason that the 'module' impact attenuators were added, along with the landing retro rockets (although both of these *also* reduced damage to the capsule -- which was designed to be resuable). Several times in the document, this lack of space for recoil was mentioned as a concern.<br /><br />However -- with the left and right equipment bays reduced in size as per my initial post (plus the size reduction of the control console) -- it's possible to spread the crew couches out such that the first and second rows are no longer directly in-line. This makes it possible to 'snug-up' the two rows of seats much closer together -- recapturing the recoil space along the x-axis. Adding the couch impact attenutators to the module ones and the retro-rockets will make for a significant reduction in G-loading to the crew on impact and seriously increase the safety margins of the craft.<br /><br />In addition -- the shock frame for the crew couches can be designed such that the back row of seats has two positions. One position will have it nearly parallel with the front row to provide the recoil space for launch and landing. The second will extend it further towards the rear of the capsule to make the capsule less confining to the crew during the orbital portion of the flight.

 

[mrmorris]

Forgot to attach the image to the above post...<br />

 

[mrmorris]

Woo Hoo! I solved the communications question for G-X3. I was just reading an article about GlobalFlyer and how NASA helped out when one paragraphed <b>jumped</b> off the page at me:<br /><br /><i>"GlobalFlyer landed safely today in Salina, Kan. after the first solo, non- stop, non-refueled around-the-world airplane trip. The flight tested NASA's advanced experimental Tracking and Data Relay Satellite System (TDRSS) transceiver called the Low Power Transceiver (LPT). As a side benefit, the NASA device allowed GlobalFlyer's mission control to communicate with Fossett for almost three days of flight through a live video connection."</i><br /><br /><br /><b>Cool</b>!!! A few minutes of Googling and I have G-X3's communications solved with a radiation tolerant system that can provide voice, video, telemetry, and IP connectivity for G-X3. It also provides GPS capabilities to boot.<br /><br /><br /><i>"Low Power Transceiver (LPT)<br />LPT is a low power, lightweight, low cost, software programmable, navigation and communication transceiver prototype.<br /><br />LPT, under joint development by National Aeronautics and Space Administration (NASA)/Goddard Space Flight Center (GSFC) and ITT Industries, represents an enabling technology for emerging, cost-effective space operations. LPT features flexible, integrated communications and navigation via Global Positioning System (GPS) with dramatically reduced size and power. The LPT receives GPS satellite signals for spacecraft navigation support and provides both forward and return data communications links to the Merritt Island (MILA) and Dryden Flight Research Facility (DFRC) Ground Stations and to the Tracking and Data Relay Satellite System (TDRSS). The experiment is designed to demonstrate the LPT’s ability to do simultaneous communications and on-board navigation, as well as multi-mode communications, reconfiguration and Internet Protocol (IP) in space."[/]</i>

 

[najab]

Ahh...but is NASA going to let you use TDRS?

 

[mrmorris]

<font color="yellow">"is NASA going to let you use TDRS? "</font><br /><br />As much as I hate making assumptions -- I think that's a fairly safe one. I don't actually like relying on it quite frankly. My preferred method of communications in the mid-long term is to use commercial telsats instead of TDRSS. In fact -- commercial telecom satellites like the Inmarsat I-4 lifting off today. A recent article in (dare I type the name?) SpaceDaily led me into researching more about Immarsat and their capabilities. The existing satellites are already used for voice and data communications with aircraft worldwide. With the three new I-4 platforms going up in the next few years, their capabilities will expand geometrically. This would be my preferred means of providing G-X3 with communications and broadband Internet connectivity. I think it will be cheaper, faster, and provide fewer operations headaches than the TDRSS solution.<br /><br />However, as with everything for the first incarnation of G-X3 -- I'm trying to be as conservative as possible and use existing space-rated hardware if it is available and a good fit for the mission. The LPT, viewed strictly as a piece of hardware, is a perfect fit. Given that NASA allowed the LPT to be used on GlobalFlyer, the <b>only</b> reason I can see NASA not allowing it to be used on G-X3 is if they are being petulant about a private firm launching an orbital craft. If they try to do this, I think they'll be crucified by Congress.

 

[mrmorris]

Well -- there's been a quetion of exactly what docking system would be used by Bigelow for his inflatables. Apparently, since he purchased the patent rights for the Low Impact Docking System (LIDS) from NASA -- this would seem to be the leading contender. Never heard of LIDS? Neither had I, until I stumbled across this article at Hobby Space.<br /><br />Investigating the LIDS further -- I found that Bigelow had applied to purchase the rights to it (I only presume they suceeded in obtaining them).<br /><br />ACTION: Notice of Prospective Patent License. <br /><br /><i>"SUMMARY: NASA hereby gives notice that Bigelow Development Aerospace Division, LLC, having offices in Las Vegas, NV, has applied for an exclusive license to practice the invention described and claimed in Patent No. 6,354,540 entitled ``Androgynous, Reconfigurable Closed Loop Feedback Controlled Low Impact Docking System With Load Sensing Electromagnetic Capture Ring,'' Case No. MSC-22931-1. "</i><br /><br />Looking up the patent itself -- it's very interesting. Few specifics, of course -- patents seldom have much meat to them (size, mass, etc.). However, they claim it's comparable to the APAS-89 -- but better. Apparently the APAS-89 isn't *truly* androgynous, as two active APAS's can't dock. Must be one active and one passive. This docking system, by contrast, *is* designed to be completely androgynous.<br /><br />Patent # 6354540<br /><br /><i>"To a certain extent, the docking system of the present invention is somewhat analogous to the Russian built Androgynous Peripheral Assembly System (APAS). The docking system disclosed herein differs, however, from the APAS in that the present invention is a "smart" electromechanical system comprised of a blend of structural/mechanical,</i>

 

[mrmorris]

Once again... forgot the image.<br /><br />

 

[tap_sa]

<font color="yellow">"Apparently the APAS-89 isn't *truly* androgynous, as two active APAS's can't dock. Must be one active and one passive."</font><br /><br />When two APAS-89s dock one is usually active and the other one passive, but physically they are the same. Only difference is that in the active shock absorbers along with docking ring are extended out while in the passive they are not (Just like in the figure above of LIDS!) . So active can be turned into passive by flip of a switch and vice versa. Why they aren't both active and extended while docking, I don't know but I guess it simplifies some things to have one be still while the other does all the aiming and aligning. Bottom line, two identical G-X3s with APAS-89s <b>can</b> dock with each other.<br /><br />To complicate things a bit, there is a simplified version of APAS-89 that can only act as passive. Just to add possibility to get confused, this version has sometimes been called as passive APAS-89, and the fully functional version as active. Physically passive version can only dock with physically active. So, when speaking of active/passive it must be clarified whether it means physical difference or configuration of the 'physically active' version. <br /><br />The LIDS appears to be able to docking while both docking rings are extended and actively seeking alignment with the other. Otherwise it's just like APAS but simple mechanical shock absorbers and latches are replaced with computer-controlled electric actuators, load sensors and electromagnets. I'm sure it works fine when things are OK but electrical glitch and your high-end docking system is nothing but a bunch of stiff rods.<br /><br />Now a question slightly related to docking: Do you plan to have any kind of window(s) ? I noticed that you used in your quick 'Apollo-X3' mass calculations the same structural mass as the original. It had a side-hatch with a window which might not be necessary today. Vidcams are light and there can be plenty

 

[nacnud]

In the same way you point out the problems with LIDS I would like to point out the problen with video cameras, electrical faliure. <br /><br />I don't know which would be better but perhaps one window would be worth it.<br /><br />I wouldn't abandon the APAS yet either it has been flown and shown to work, I'd leave the LIDS for GX3 Block 2 <img src="/images/icons/smile.gif" />

 

[soyuztma]

I think you may be interested in this:<br />NASA NOTIFICATION OF EXPLORATION MISSION DOCKING SYSTEMS FORUM.<br />They seem to be planning a meeting to give an overview of the LIDS system. <div class="Discussion_UserSignature"> </div>