Epsilon (rocket)

The Epsilon (Japaneseイプシロン ロケット, Ipushiron roketto ) is a Japanese solid rocket with optional liquid-propellant upper stage. Epsilon, called ε after the 5th Greek letters, is the successor of Mu V rocket. The first launch took place on 14 September 2013.


The Epsilon is how the Mu -V, in four stages. It differs, inter alia, to from this fact that the expensive Mu -V first stage is replaced by a cheaper SRB -A solid rocket boosters of the H-IIA as a first stage. Also new is the optional fourth stage, post Stage Boost is called, which is to be used in the Epsilon Compact Liquid Propulsion system with liquid fuel to increase the bullet accuracy. It replaces optional fourth solid level of Mu -V. The second stage is a revised third stage of Mu -V. The third stage of Epsilon, however, is also a new development.


The fairing surrounding the payload with the epsilon addition, the fourth stage and the third stage, but not the exhaust nozzle. The third stage is spin stabilized. The spin can undo prior to exposure of the payload, the optional fourth stage. The Epsilon as the SRB -A booster of the H-IIA rocket, 2.5 meters in diameter, 24 meters long and has a launch mass of 91 tons. Your payload into an elliptical orbit between 250 km and 500 km altitude is 1200 kg with the use of the first three stages. Four stages they transported 700 kg in a circular 500 - km railway, or 450 kilograms in a circular 500 km high Sun-synchronous orbit. By the use of stiffer carbon fibers for the production of CFRP, the solids levels of these combustion chambers are easier than for the Mu -V. A novel fabrication process to get there without baking the CFRP.

Launch preparations

The Epsilon launches from the modified former launch site of the Mu -V. The assembly of the rocket is supposed to be faster than the previous model, so that the starting seven days after the start of the construction is to take place on the starting grid. The Epsilon controlled with their computer systems during the countdown and the launch itself, which is why it needs only a very small team to start preparation and start-up supervision. During her flight to the target track the rocket from 2017 to oversee with more advanced computer systems fully self contained, so that tracking stations, including be unnecessary to send a self-destruct signal. Although a start only half as much to cost as one of the Mu -V, due to the lower payload capacity of Epsilon the starting price per kg payload is only 25 % less than in the Mu -V.

The Epsilon has been developed since 2007. The development costs amounted to about 255 million U.S. dollars. With 47 million dollars a Epsilonstart should be like a Mu V Start ( 94 million dollars ) for about half the price.

First start

The first launch was scheduled for August 27, 2013 04:45 UTC clock, but was canceled due to irregularities s 19 before the start. He was then on the second attempt on 14 September.

State of the list: September 14, 2013

Planned start

State of the list: September 14, 2013