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H3 Launch Vehicle

Japan's H3 rocket failed in its first launch 06 March 2023. The rocket lifted off from the Tanegashima Space Center at 8:37 p.m. Eastern, and the vehicle's first stage, along with two solid-fuel boosters, appeared to perform as planned. However, controllers were unable to confirm that the rocket's second-stage engine ignited as telemetry showed the vehicle losing speed. Those controllers later sent a destruct signal to the rocket. A destruct command was transmitted to H3 around 10:52 a.m. (Japan Standard Time), because there was no possibility of achieving the mission. Neither the Japanese space agency JAXA or vehicle manufacturer Mitsubishi Heavy Industries provided additional details about the failure.

The H3 Launch Vehicle is a large-size next-generation launch vehicle whose maiden flight is scheduled in Japan Fiscal Year 2020 from the Tanegashima Space Center. H3 is under development to be a successor to the H-IIA Launch Vehicle, the current mainstay launch vehicle, in order to maintain Japan’s autonomous access to space. H3 aimed to become a launch vehicle that attracts people’s attention not only in Japan but also globally as an easy-to-use space transportation system.

For H3 to succeed, JAXA will modernize the overall launch vehicle based on our experience cultivated through the development and operation of H-IIA. In that sense, JAXA faced technological challenges including the development of a new large liquid engine (LE-9) and solid rocket boosters (SRB-3). Technologies developed for H3 will be applied to the Epsilon Launch Vehicle. JAXA and related companies will make active use of Japanese technologies in various fields to develop the new launch vehicle.

Based on investigation and prediction of what kind of launch needs will arise in 2020 and beyond, the H3 Launch Vehicle aims at achieving three factors namely, high flexibility, high reliability, and high cost performance. JAXA will offer an appropriate launch price and capability for each user’s needs by preparing various launch vehicle configurations. JAXA can also respond promptly to customers’ requests for launching their payloads by reducing the launch preparation period. By inheriting the high launch success rate of the H-IIA Launch Vehicle, H3 will also offer a reliable launch. The launch service price will be lower compared to that of H-IIA

JAXA would offer a selection of two types of fairings, two or three units for the first-stage engines (LE-9) and zero, two or four solid rocket boosters (SRB-3) to cope with various payload sizes and their orbits. We also set a high launch capability to the geostationary transfer orbit (GTO) that exceeds the capabilities of H-IIA and H-IIB.

The Japan Aerospace Exploration Agency (JAXA) announced the official naming of the Next Generation Launch Vehicle currently under development 02 July 2015. The name was decided in coordination with the prime contractor (Mitsubishi Heavy Industries, Ltd.) to develop the Next Generation Launch Vehicle in order to achieve flexible and diversified demands. Name: H3 Launch Vehicle (Abbreviation: H3) The major reasons for the selection are as follows: The “H” stands for a successful heritage of our H-IIA/H-IIB Launch Vehicles. The “3” implies our innovative challenge.

JAXA tested LE-5B-3, the liquid rocket engine designed to propel the second stage of H3 Launch Vehicle now under development. LE-5B-3 enhances the LE-5B-2 engine that likewise boosts the second stage of H-IIA and H-IIB. LE-5B-2 has earned the time-tested record of reliability after scores of successful H-II launches. Improvements are being made to lower the cost of LE-5B-3, without compensating the dynamics to blast off H3, a larger rocket and to sustain its flight.

Following the design improvements for affordability and performance which reached the desired level in August 2016, JAXA successfully conducted the test of the liquid hydrogen turbopump in December 2016 through January 2017. The liquid hydrogen turbopump -- equivalent of the heart of a human body -- draws in the propellants into the engine thrust chamber.

Since March 2017, the first engine with the hydrogen turbopump, assembled for certification was completed, kicking off its preliminary firing testing. The test is proceeding on schedule. By September 2017, test results will expectedly prove the soundness of the basic design improvements.

SRB-3 is an auxiliary rocket under development as solid rocket booster to be attached to the base of the H3 rocket. Strap-on solid rocket boosters derived from SRB-3 reinforce H3’s launch capabilities. Varied configuration – zero, two or four booster(s), depending on the desired thrust – gives the launch vehicle a higher degree of flexibility, one of its strengths. JAXA pursuits cost reduction by use of the technology that produced SRB-A, H-II rocket’s first stage engine, and simplification of the attachment methods. The SRB-3 rocket motor, almost the same size as SRB-A’s, is also configured for the first stage of the Epsilon launch vehicle. Based on the design review, since April 2017, JAXA started testing motor strength using the full-scale motor case. SRB-3 is subject to a series of tests, including ground firing and separation.

On December 6, 2018 Inmarsat, the world leader in global mobile satellite communications, announced that it has entered into an agreement with Mitsubishi Heavy Industries, Ltd. (MHI) to be the first commercial customer to place an order for the new H3 launch vehicle. The maiden flight of H3 is scheduled for 2020 with Inmarsat planning to deploy the new launch vehicle after 2022.

This was the second agreement entered by Inmarsat and MHI, following the launch services contract awarded to MHI's H-IIA Launch Vehicle in 2017. These agreements underline the growing partnership between the two companies in the area of launch services.

Rupert Pearce, CEO of Inmarsat, said: "Inmarsat is the world leader in global mobile satellite communications; a position we have achieved by building an exceptional ecosystem of partners. As our company grows - expanding into new markets and opening up new opportunities for our customers to develop their businesses - we continually seek new technology partners that display an outstanding commitment to innovation and excellence. "It was for these reasons that in 2017 we selected MHI as a launch partner and why today we are delighted to be announcing that Inmarsat is the first commercial customer to select MHI's new H3 launch vehicle. We believe that H3 represents a world-class innovation and one that will deliver an effective and efficient service to place future Inmarsat satellites into orbit."

"Today, development of the H3 Launch Vehicle is proceeding steadily forward under the leadership of the Japan Aerospace Exploration Agency (JAXA), with MHI serving as primary contractor working closely with key component manufacturers," said Masahiro Atsumi, Vice President & Senior General Manager for Space Systems at MHI. "We greatly appreciate the high evaluation made by Inmarsat during this development phase and, working closely with JAXA and government agencies, we will do everything possible to ensure that development results in a new flagship launch vehicle fully meeting the customer's high expectations."

Rt Hon Greg Clark MP, Secretary of State for Business said: "Science and innovation have no borders, as long-term strategic partnerships like this one built on excellence between Inmarsat in the UK and MHI in Japan demonstrate. The space sector is a UK success story and an industry that is growing globally, a year since the launch of our modern industrial strategy, we continue to build on our commitment to space, including through the announcement of the UK's first spaceports and record investment in our world leading science base."

MHI Launch Services enjoyeds an extremely high success rate of 97.9% and has provided 41 successful consecutive launches since 2005, elivered on-time and to the customer's satisfaction by current launch vehicle both H-IIA and H-IIB. The agreement with Inmarsat reflects MHI's long-term commitment to supporting a wide range of customers in the space industry. MHI will continue to support the development of the space industry, and will seek further new opportunities in this field both in Japan and globally.

JAXA plans to launch six H3 rockets annually, phasing out the older H-IIA rocket, its current mainstay, after its 50th launch later this fiscal year, which runs through March 2025.