Japan\u2019s Epsilon rocket conducted its second flight Tuesday, orbiting JAXA\u2019s ERG satellite to study Earth\u2019s radiation belts. Liftoff from the Uchinoura Space Centre was on schedule at 20:00 local time (11:00 UTC), the opening of what was an hour-long launch window.<\/p>\n
Epsilon-2 Mission:<\/p>\n
The Exploration of Energisation and Radiation in Geospace (ERG) mission will be operated by the Japan Aerospace Exploration Agency (JAXA), studying Earth\u2019s magnetosphere.<\/p>\n
Also known as SPRINT-B, ERG is a 365-kilogram (805 lb) satellite based on JAXA\u2019s SPRINT bus, which was demonstrated by 2013\u2019s Hisaki \u2013 or SPRINT-A \u2013 mission. The spacecraft measures 1.5 by 1.5 by 2.7 meters (4.9 x 4.9 x 8.9 feet) in its launch configuration.<\/p>\n
![\"\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/12\/2016-12-20-021713-350x253.jpg\")
Once in orbit, ERG will deploy its instrument booms and solar arrays. With a span of 6.0 meters (19.7 feet) along the satellite\u2019s x-axis and 5.2 m (17.1 ft) meters along its y-axis, the solar panels will generate over 700 watts of power for the spacecraft\u2019s systems and instruments.<\/p>\n
Following initial operation and testing, ERG is expected to operate for at least a year.<\/p>\n
The ERG satellite carries instruments dedicated to the study of plasma, particles, waves and fields in Earth\u2019s radiation belts.<\/p>\n
Earth\u2019s radiation belts were discovered by James Van Allen\u2019s experiments aboard the first US satellite, Explorer 1, in 1958 although their existence had previously been theorized by other scientists. As a result, the belts are known as the Van Allen belts.<\/p>\n
Earth has two permanent radiation belts, the inner and outer Van Allen belts, although NASA\u2019s Van Allen Probes, or Radiation Belt Storm Probes (RBSP), which were launched in August 2012, showed that a third belt can form and dissipate.<\/p>\n
Technology News (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n ERG\u2019s Plasma and Particle Experiment (PPE) instrument suite consists of electron and ion mass analyzers. The Low Energy Particle Experiments \u2013 Electron Analyser (LEP-e), Medium Energy Particle Experiments \u2013 Electron Analyser (MEP-e), High Energy Electron Experiments (HEP) and Extremely High Energy Electron Experiments (XEP) instruments will study electrons at increasing energies between 10 electronvolts and 20 megaelectronvolts.<\/p>\n Low Energy Particle Experiments \u2013 Ion Mass Analyser (LEP-i) and Medium Energy Particle Experiments \u2013 Ion Mass Analyser (MEP-i) are mass spectrometers which will be used to study the different types of ions present in ERG\u2019s environment.<\/p>\n The Plasma Wave Experiment (PWE) will measure the Earth\u2019s electric and magnetic fields as the satellite passes through them, up to frequencies of 10 megahertz and 100 kilohertz respectively.<\/p>\n This will be complimented by the Software-Type Wave Particle Interaction Analyser (S-WPIA), software aboard ERG\u2019s computer systems, will attempt to quantify energy transferred between waves and electrons through the spacecraft\u2019s observations of plasma waves and particles.<\/p>\n A replacement for the earlier M-V rocket, which retired in September 2006, Epsilon is designed to provide a ride to orbit for Japan\u2019s smaller satellites. Epsilon uses an SRB-A3 motor \u2013 used as a strap-on booster on the larger H-IIA and H-IIB rockets \u2013 as its first stage with upper stages derived from the M-V.<\/p>\n Epsilon launches from the Uchinoura \u2013 formerly Kagoshima \u2013 Space Centre, using the same launch pad from which the M-V flew.<\/p>\n Also used by earlier members of the Mu family of rockets \u2013 of which the M-V was the final member \u2013 the complex was originally constructed in the 1960s.<\/p>\n It consists of an assembly tower with the rocket mounted upon a movable launcher platform which is rotated into position ahead of launch. This was originally built as a rail launcher for the Mu series, however a pedestal has been added for Epsilon with the former support structure for the rail serving as an umbilical tower.<\/p>\n The vehicle has been described as \u201cEpsilon-2\u201d, however it is presently unclear whether this name refers to the enhanced configuration, or to Tuesday\u2019s launch being Epsilon\u2019s second flight.<\/p>\n Epsilon\u2019s launch began with first stage ignition and liftoff, when the countdown reached zero. The rocket flew in a south-easterly direction, along an azimuth of 100 degrees. Its first stage burned for 109 seconds, accelerating the vehicle to a velocity of 2.5 kilometers per second (5,600 mph). At burnout, Epsilon was at an altitude of 71 kilometers (44 miles, 38 nautical miles) and 75 kilometers (47 miles, 40 nautical miles) downrange.<\/p>\n After the end of the first stage burn, Epsilon entered a coast phase as it ascends into space. Around 41 seconds after burnout, at an altitude of 115 kilometers (71.5 miles, 62.1 nautical miles), the payload fairing separated from the nose of the rocket. Eleven seconds later the spent first stage was jettisoned.<\/p>\n Epsilon-2 had an M-35 second stage, in place of the M-34c used on the maiden flight. The new stage is larger than its predecessor and has a fixed nozzle instead of the extendible nozzle used on the M-34c. The M-35 generates 445 kilonewtons of thrust, an increase from the 327 kilonewtons generated by the M-34c, and burns for fifteen seconds longer.<\/p>\n A second coast phase took place between second stage burnout and third stage ignition. One minute and forty-five seconds after burning out, the second stage separated with the third stage igniting four seconds later. During the coast phase the third stage was spun-up; spin-stabilisation was used to help it maintain attitude during its burn.<\/p>\n For Tuesday\u2019s launch the third stage was also been upgraded, with Epsilon-2 using a KM-V2c instead of the KM-V2b that flew on the 2013 launch. This uses a fixed nozzle instead of an extendible one, but has no significant difference in performance. The third stage will burn for about 89 seconds.<\/p>\n Epsilon can fly with a liquid-fuelled fourth stage, the Compact Liquid Propulsion System (CLPS), which was used on its first launch. This is not required for Tuesday\u2019s launch, so instead the rocket flew in its all-solid three-stage configuration for the first time.<\/p>\n Tuesday\u2019s launch was targeting an elliptical orbit with a perigee \u2013 the point closest to Earth \u2013 of 219 kilometers (136 miles, 118 nautical miles) and an apogee \u2013 or highest point \u2013 of 33,200 kilometers (20,600 miles, 17,900 nautical miles).<\/p>\n The orbit will have inclination of 31.4 degrees to the equator, with the satellite taking about 580 minutes \u2013 or 9.7 hours \u2013 to complete one revolution.<\/p>\n Tuesday\u2019s launch was Japan\u2019s fourth and last of 2016, following H-IIA missions in February and November which deployed the Hitomi observatory and the Himawari 9 weather satellite \u2013 and an H-IIB launch earlier this month with the Kounotori 6 spacecraft to resupply the International Space Station.<\/p>\n Japan\u2019s next launch, currently scheduled for 11 January, will be an experimental flight which aims to use a modified SS-520 sounding rocket to orbit a single three-unit CubeSat. An H-IIA launch carrying the DSN-2 communications satellite is also scheduled for January.<\/p>\n The next Epsilon launch will carry the ASNARO-2 experimental radar imaging satellite. This is expected to occur during Japan\u2019s 2017 financial year, which begins on 1 April.<\/p>\n (Image via JAXA).<\/p>\n","protected":false},"excerpt":{"rendered":" Japan\u2019s Epsilon rocket conducted its second flight Tuesday, orbiting JAXA\u2019s ERG satellite to study Earth\u2019s radiation belts. Liftoff from the Uchinoura Space Centre was on schedule at 20:00 local time (11:00 UTC), the opening of what was an hour-long launch window. Epsilon-2 Mission: The Exploration of Energisation and Radiation in Geospace (ERG) mission will be […]<\/p>\n","protected":false},"author":1,"featured_media":29987,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[2762],"class_list":["post-38897","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-epsilon"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38897"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=38897"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38897\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/29987"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=38897"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=38897"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=38897"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/12\/2016-12-20-021637-350x222.jpg\")
ERG will join NASA\u2019s two Van Allen Probes and three earlier Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecraft in making in-situ observations of the Van Allen belts. These will be joined by the UA Air Force Research Laboratory\u2019s DSX satellite, currently scheduled for launch aboard SpaceX\u2019s Falcon Heavy rocket next year.<\/p>\nSee Also<\/h4>\n
\n
![\"\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/12\/2016-12-20-022000-350x236.jpg\")
ERG launched atop JAXA\u2019s solid-fuelled Epsilon rocket, which made its first flight in September 2013 and has not flown since.<\/p>\n![\"\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/12\/2016-12-20-021852-350x322.jpg\")
Tuesday\u2019s launch was the first flight of the operational or \u201cEnhanced Epsilon\u201d configuration, introducing improvements to the upper stages over those used on the maiden flight.<\/p>\n![\"\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/12\/2016-12-20-022131-350x293.jpg\")
The second stage ignited four seconds after first stage separation, burning for two minutes and eight seconds.<\/p>\n![\"\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/12\/2016-12-20-022243-350x255.jpg\")
Spacecraft separation occurred thirteen minutes and twenty-seven seconds after liftoff; five minutes and sixteen seconds after third stage burnout.<\/p>\n