Next success of JAXA after HTV-6 cargo mission. Their experimental rocket Epsilon delivered to orbit Exploration of energization and Radiation in Geospace (ERG) satellite today. It was second successful flight of Epsilon in the history of the program which started in 2007.
Today Japanese space agency JAXA managed to perform successful launch of the latest version of their experimental small launch vehicle -Epsilon rocket. As far as general characteristics of Epsilon remained unchanged since last launch in 2013, some important upgrades were implemented. Rocket made by IHI Aerospace still is based on three solid fueled stages. Upgraded rocket has longer payload fairing – Epsilon launched today was long for 26 m compared to previous version long for 24.4 m. Diameter is unchanged – 2.5 m. Mass of the rocket is 95 t – previous version weight was at 91 t. Modified version is able to deliver 1.5 t to 250 km x 500 km orbit (versus 1.2 t) and to SSO 500 km x 500 km orbit 0.6 t (versus 0.45 t in previous version). It is possible, that modifications will be continued and in 2017, when JAXA planned another launch of Epsilon (with Asnaro-2 X band radar satellite), we will see different version of Epsilon.
Epsilon was launched from KS launch pad at Uchinoura Space Center, placed 70 km across the Osumi Strait from Tanegashima Space Center. As the launch was planned for 11:00 UTC, already on 08:39 UTC rocket was standing on the pad. Launch procedure is simplified comparing to liquid fueled rockets – rocket is connected to different ports and interfaces and tests of onboard systems are conducted. There is no fueling and pressurizing the tanks; no opening of pre valves and nervous atmosphere in case of countdown hold. Rocket is fired as it was delivered from factory. JAXA claims, that it is possible to launch Epsilon in nine days ,what sounds very attractive comparing to month-long launch campaigns of liquid fueled rockets. Two minutes before launch rocket was in perfect condition – weather forecasts were still favorable with clear sky and slight wind. Finally at 11:00 UTC first stage, equipped with SRB-A3 engine, was ignited and rocket started to rise over Kappa launch pad. Propulsion of the first stage, SRB-A3, is providing 2271 kN of thrust. First stage is 2.5 m in diameter, with length at 11 m and mass of 75 t. Engine is fueled with 66 t of BP-207J propellant. After first 60 seconds rocket reached speed of 1 Ma and at T+2′ engine was cut off. Rocket was on the correct course to East and at T+2’36” payload fairing was jettisoned. First stage was separated at T+2’50” to let second stage to ignite. Second stage is long for 5.16 m with diameter at 2.5 m and mass at 17200 kg. It is equipped with M-34C engine providing 371.5 kN and fueled with PB based propellant. After ignition it operated for almost three minutes and at T+5’40” it was cut off. After phase of ballistic flight on 235 km orbit, rocket jettisoned second stage at T+7’15”. Weighing 2.5 t and long for 1.45 m (with diameter at 2.25 m) third stage ignited its KM-V2C (99.6 kN fueled with HTPB) for another minute and deployed ERG at 11:18 UTC. At 11:37 UTC satellite reported its good condition and deployed its solar arrays.
ERG satellite (nicknamed Arase) and known also as Sprint-B is scientific satellite objected on research on ionosphere of Earth. It was built on SPRINT satellite bus; it weighs 350 kg and is powered by four deployable solar arrays. It will operate on 300 km x 30000 km orbit with inclination of 31°. Its mission is mainly devoted measuring charge of electrons remaining inside Van Allen belt and how space storms affect on them. It will use number of devices: extremely high-energy electron experiments (XEP-e), high-energy electron experiments (HEP-e), medium-energy particle experiments – electron analyzer (MEP-e), low-energy particle experiments – electron analyzer (LEP-e), medium-energy particle experiments – ion mass analyzer (MEP-i), low-energy particle experiments – ion mass analyzer (LEP-i), magnetic field experiment (MGF), plasma Wave Experiment (PWE) and software-type wave particle interaction analyzer (S-WPIA).