H-IIA (H-2A) is an active expendable launch system operated by Mitsubishi Heavy Industries (MHI) for the Japan Aerospace Exploration Agency.
- Type : Medium-lift launch vehicle.
- Origin : Japan.
- Manufacturer: Mitsubishi Heavy Industries (prime), Northrop Grumman, Innovation Systems (sub).
- In service : 202: 29 August 2001 - Active, 204: 204: 18 December 2006 - Active.
- Mass : 285,000–445,000 kg (628,000–981,000 lb).
- Length/Height : 53 m (174 ft).
- Diameter : 4 m (13 ft).
- Payload to LEO : 10,000–15,000 kg (22,000–33,000 lb).
- Payload to GTO : 4,200–6,000 kg (9,300–13,200 lb).
- Propellant: Boosters: HTPB solid. First/Second stage: LH2 / LOX.
- Engines: Boosters: 2-4 SRB-A with thrust of 4,520–9,040 kN (1,020,000–2,030,000 lbf), 2-4 Castor 4A-XL with thrust of 1,490–2,980 kN (330,000–670,000 lbf). First stage: 1 LE-7A with thrust of 1,098 kN (247,000 lbf). Second stage : 1 LE-5B with thrust of 137 kN (31,000 lbf) .
These liquid fuel rockets have been used to launch satellites into geostationary orbit; lunar orbiting spacecraft; Akatsuki, which studied the planet Venus; and the Emirates Mars Mission, which was launched to Mars in July 2020. Launches occur at the Tanegashima Space Center. The H-IIA first flew in 2001. As of November 2020, H-IIA rockets were launched 43 times, including 37 consecutive missions without a failure, dating back to 29 November 2003.
Production and management of the H-IIA shifted from JAXA to MHI on 1 April 2007. Flight 13, which launched the lunar orbiter SELENE, was the first H-IIA launched after this privatization.
The H-IIA is a derivative of the earlier H-II rocket, substantially redesigned to improve reliability and minimize costs. There have been four variants, with two in active service (as of 2020) for various purposes. A derivative design, the H-IIB, was developed in the 2000s and made its maiden flight in 2009.
The launch capability of an H-IIA launch vehicle can be enhanced by adding SRB-A solid rocket booster (SRB) and Castor 4AXL solid strap-on booster (SSB) to its basic configuration. The models are indicated by three or four numbers following the prefix "H2A":