|
The H-II Transfer Vehicle (HTV), also called , is an automated cargo spacecraft used to resupply the ''Kibō'' Japanese Experiment Module (JEM) and the International Space Station (ISS). The Japan Aerospace Exploration Agency (JAXA) has been working on the design since the early 1990s. The first mission, HTV-1, was originally intended to be launched in 2001. It launched at 17:01 UTC on 10 September 2009 on an H-IIB launch vehicle.〔(【引用サイトリンク】title=NASA Sets Briefing, TV Coverage of Japan's First Cargo Spacecraft )〕 The name ''Kounotori'' was chosen for the HTV by JAXA because "a white stork carries an image of conveying an important thing (a baby, happiness, and other joyful things), therefore, it precisely expresses the HTV's mission to transport essential materials to the ISS". == Design == The HTV is about 9.8 m long (including maneuvering thrusters at one end) and 4.4 m in diameter. Total mass is 10.5 tonnes, with a payload.〔 〕 The HTV are comparable in function to the Russian Progress, European ATV, commercial Dragon, and commercial Cygnus spacecraft, all of which bring or are planned to bring supplies to the ISS. Like the ATV, the HTV carries more than twice the payload of the Progress, but is launched less than half as often. Unlike Progress capsules and ATVs, which dock automatically, HTVs and American commercial crafts approach the ISS in stages, and are signaled by ISS crew or ground control to continue from one holding point to the next. Once they reach their closest parking orbit to the ISS, crew grapple them using the robotic arm Canadarm2 and berth them to an open berthing port on the ''Harmony'' module.〔http://www.aprsaf.org/data/aprsaf17_data/DAY1-seu_0950-Kibo_Utilization_Status.pdf 〕 The HTV has an external payload bay which is accessed by robotic arm after it has been berthed to the ISS. New payloads can be moved directly from the HTV to ''Kibōs exposed facility. Internally, it has eight International Standard Payload Racks (ISPRs) in total which can be unloaded by the crew in a shirt-sleeve environment. After the retirement of NASA's Space Shuttle in 2011, HTVs became the only spacecraft capable of transporting ISPRs to the ISS. (The SpaceX Dragon and Orbital Sciences Cygnus can carry resupply cargo bags but not ISPRs.) The intention of HTV's modularized design was to use different module configuration to match the mission requirement. However, to reduce the development cost it was decided to fly the mixed PLC/ULC configuration only. To control the HTV's attitude and to perform the orbital maneuvers such as rendezvous and re-entry, the craft has four 500 N class main thrusters and twenty-eight 110 N class attitude control thrusters. Both use bipropellant, namely monomethylhydrazine (MMH) as fuel and mixed oxides of nitrogen (MON3) as oxidizer.〔IAC paper IAC-05-C4.1.03 - Shinobu Matsuo and al. "The design characteristics of the HTV propulsion module"〕 HTV-1, -2, and -4 use Aerojet's 110 N R-1E, Space Shuttle's vernier engine, and the 500 N based on the Apollo spacecraft's R-4D.〔 Later HTVs use 500 N class HBT-5 thrusters and 120 N class HBT-1 thrusters made by Japanese manufacturer IHI Aerospace Co., Ltd. The HTV carries about 2400 kg of propellant in four tanks.〔 After the unloading process is completed, the HTV will be loaded with waste and undocked. The vehicle will then deorbit and be destroyed during reentry, the debris falling into the Pacific Ocean.〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「H-II Transfer Vehicle」の詳細全文を読む スポンサード リンク
|