credit JAXA
The Japan Aerospace Exploration Agency (JAXA)'s rocket and spacecraft development establishment, the Tsukuba Space Center, has produced a concept for a four-crew capsule that is part of a Mitsubishi Heavy Industries H-IIB rocket launched spacecraft consisting of four modules, the Launch Escape System (LES), Manned Re-entry Module (MRM), Orbital Habitation Module (OHM) and Propulsion Module (PM)
Designed for LEO missions the JAXA's 2025 vision includes a Japanese human spaceflight capability and the concept work has been drawn up in preparation for possible formal design cycles
The spacecraft is a 16,800kg (36,960lb), 4m (13.1ft)-diameter vehicle that would use systems from Japan's International Space Station resupply ship H-IIB Transfer Vehicle (HTV) for its 3,800kg (fuelled) PM and 5,000kg OHM. Examples include the engines, the Environmental Control and Life Support Systems (ECLSS), electrical power network and avionics. However JAXA expects to have to find some mass savings in the HTV systems
credit: JAXA
The OHM would also provide life support for the 5,000kg MRM during periods on-orbit. This would enable the MRM ECLSS to be smaller. JAXA flight tested its Orbital Re-Entry Flight Experiment in 1994 and this would aid the MRM's development. No final decision has been taken on the MRM's shape but the agency wants to employ controlled lift for a lift/drag ratio of 0.4
credit JAXA
The LES is 3,000kg making up the final 16,800kg figure. Like Soyuz JAXA's spacecraft will abort with its habitation module attached meaning it will probably require the four folding drag plates that are used to control the aborting Soyuz's aerodynamics before its parachute controlled descent starts
In an odd change to the norm JAXA wants, understandably, to have its MRM in the normal launch orientation but then on orbit to use a mechanical guidance "rail and wheel system" to move the RM forwards, round and back so it can 'dock' with its OHM
credit: JAXA
JAXA envisages four demonstration flights, two unmanned and two manned. The first demonstrates the MRM's re-entry performance, the second the LES, and the operational H-IIA rocket could be used for these. The third is a manned on-orbit demonstration and the fourth is a full mission and both would need the H-IIB
The LEO mission would involve two or three days to reach the space station and then an on-orbit capability of one to two further weeks. JAXA rules out a lunar mission as it's beyond the H-IIB's "launch capability". What no double launch mission?
Like China's orbital module JAXA envisages its OHM as potentially becoming an additional module for a space station
on January 10, 2009 3:50 AM | Reply
Very interesting, and I hope they're successful if they pursue this technology. But one might have thought that, after all their work on the RVT, Japan would pursue a human path into space that didn't involve more ballistic capsules on top of expendables...
http://www.jaxa.jp/news_topics/column/no3/index_e.html
http://www.hobbyspace.com/nucleus/index.php?itemid=3966
http://www.isas.jaxa.jp/j/enterp/tech/vehicle/rvt/rvt.mov (60mb Quick Time video in Japanese)
on January 10, 2009 4:12 AM | Reply
Dear Rob,
You did not mention source of information:
Preliminary Study for Manned Spacecraft with Escape System and H-IIB Rocket
By Takane Imada, Michio Ito, Shinichi Takata Japan Aerospace Exploration Agency, Tsukuba, Japan.
26th International Symposium on Space Technology and Science (Hamamatsu, Japan, 1-8 June 2008).
Link: http://www.senkyo.co.jp/ists2008/pdf/2008-g-14.pdf
on January 10, 2009 4:58 AM | Reply
Bit confused Rob.
My take on the really cute proposed mechanical guidance "rail and wheel system" to move the RM (command module?) forwards, round and back so it can 'dock' with its OHM is precisely to avoid the need for a Soyuz-like abort sequence with its associated drag plates and habitation module post-abort jettison requirement. The JAXA spacecraft “command module” can simply be pulled free on its own with no other “entanglements.” Looks quite clever to me unless, that is, we are looking at different pictures?
Best,
Geoffrey V. Hughes
on January 10, 2009 2:23 PM | Reply
If it works the 'Rail and Wheel System' could make docking with the Orbital Habitat Module a doddle. If it fails though it could mean an aborted mission at best - or a Re-entry Module sandwiched between the OHM and the Propulsion Module, the crew being trapped in orbit...
Haven't they heard of Gemini B?
That said, the Japanese are in love with 'techy' solutions. We have a mini-shinkansen where we live in Japan - once it reaches the main bullet train lines it clamps onto the back of the real thing and gets a free ride to Tokyo. Very Thunderbirdy.
on January 12, 2009 3:42 AM | Reply
Bit confused Rob.
My take on the really cute proposed mechanical guidance "rail and wheel system" to move the MRM (command module) forwards, round and back so it can 'dock' with its OHM is precisely to avoid the need for a Soyuz-like abort sequence with its associated drag plates and habitation module post-abort jettison requirement. Positioned on the top of the stack, on abort, the JAXA spacecraft MRM command module can simply be pulled free on its own with no other “entanglements.” Looks quite clever to me. Are we both looking at the same pictures?
Best,
Geoffrey V. Hughes
on January 12, 2009 9:04 AM | Reply
Thanks. Thanks for telling everyone, and other space journalists included, where I get my info from. It's really, really, really, appreciated. not.
on January 12, 2009 9:08 AM | Reply
That's not what the technical paper says. It posits the fact that with a habitation module the centre of gravity is way below the capsule and that the Russians use drag plates to ensure good aerodynamics after ascent abort separation, indicating the need for a similar system with the H-IIB spacecraft. The wheel and rail system is only referred to for the docking of the capsule with the habitation module.
on January 12, 2009 8:49 PM | Reply
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just a little problem... WHERE they'll find the $10+ billion to develop and build the Orion's clone?
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on January 13, 2009 5:34 AM | Reply
Sorry Rob, much as I appreciate the insight you bring us through Hyperbola, I must continue to disagree.
It is my belief that JAXA is using the Apollo model for their LES (Launch Escape System) design not the Soyuz one. They appear to believe the Apollo system is superior as it is both simpler and lighter.
Close study of the JAXA paper by Imada et al. particularly Fig. 10. Module Construction (study the “at launch” configurations in purple), Figure. 13. Launch Escape System (clearly shows only LES and MRM), and Table 4. Parameters in Launch Escape Systems (line 2) strongly suggest to me that my initial take on the really cute mechanical guidance "rail and wheel system" (to allow the the MRM to 'dock' with its OHM once on-orbit) is precisely to avoid the need for a Soyuz-like abort system with its greater weight, complexity, drag plates, and habitation module post-abort jettison requirement, is correct.
This way, on launch, the MRM is positioned on the top of the stack and, on abort, can simply be pulled free by the LES on its own with no other “entanglements.”
While the authors do muddy the waters by discussing Soyuz, it is my belief, that like so many technical papers, particularly ones translated into another language (this one was written in Japanese and translated into English) “challenges” in writing and translating have complicated what is in reality a very simple and clever concept.
Additionally, the item in Table 3. Component Tree of LES, under mechanics, called “control surface deployment mechanism” strongly suggests to me the proposed use of canards on the LES tower as were used on the Apollo LES and as proposed for the Orion LES rather than drag plates as per Soyuz.
Trust this helps.
Best,
Geoffrey V. Hughes