H3 Launch Vehicle by Mitsubishi Heavy Industries (MHI): status and timeline

Milestones

Next · Quarterly QZSS deployments through 2027

H3 program approved by Japanese government17 May 2013Complete.
Development begins; LE-9 engine qualification2014Complete.
Maiden flight fails; second-stage ignition fault7 Mar 2023Complete.
Second test flight succeeds; HTV-X test payload reaches orbit17 Feb 2024Complete.
H3-24 launches HTV-X1 cargo to ISS26 Oct 2025Complete.
H3-22S fails; payload adapter defect22 Dec 2025Complete.
H3-30 maiden flight succeeds; no-booster variant12 Jun 2026Complete.
H3-24 launches QZS-7 to GTO; seventh success11 Aug 2026Complete.

Most important updates

H3-24 launches QZS-7 satellite to GTO; seventh successful flight11 Aug 2026
H3-30 maiden flight succeeds; no-booster variant reaches orbit12 Jun 2026
H3-22S fails; payload adapter defects prevent orbit insertion22 Dec 2025
H3-24 successfully launches HTV-X1 cargo to ISS26 Oct 2025
H3 second test flight succeeds; reaches intended orbit17 Feb 2024

Upcoming

Q2 2027Quarterly QZSS deployments through 2027 (next)
Q3 2027Begin commercial ISS resupply missions
Q2 2028Lunar and Mars exploration probe missions

Current obstacles

Reliability after early failuresMarch 2023 maiden flight and Dec 2025 failure hurt confidence; consecutive successes essential.
Meeting cost targets in practiceGovernment-funded development can subsidize early flights; proving commercial affordability at $50 million per mission requires sustained volume.
International commercial competitivenessSpaceX's Falcon 9 reusability, Ariane 6's reliability and Chinese Long March aggressive pricing create a crowded market.

Physics limits

Hydrogen-oxygen rocket chemistry limitsLiquid hydrogen engines offer high specific impulse (~450 seconds) but require cryogenic storage and complex ground handling, adding operational complexity and cost.
Expander-bleed cycle trade-offsThe LE-9's new expander-bleed turbopump design reduces power and thrust compared to traditional staged-combustion designs, limiting future growth and reusability.
Launch cadence limited by infrastructureA single launch complex at Tanegashima Space Center limits launch frequency; unlike SpaceX's Merlin engines, the LE-9 cannot be mass-produced for rapid turnaround.

How it works

3 parts

First Stage

Modular LE-9 engines

H3-30 uses one LE-9 (147 mt thrust); H3-24 uses three plus up to four SRB-3 solid boosters.

Second Stage

LE-5C upper stage

Proven LE-5C engine can reignite multiple times for orbit insertion and multi-payload deployment.

Cost Control

Streamlined design

Common off-the-shelf avionics and manufacturing reduce development and per-flight costs.

Spec sheet

Spec	H3 Launch Vehicle
H3-30 payload to sun-synchronous orbit	4,000 kg^R (reported)
H3-24 to geostationary orbit	7,900 kg^R (reported)
H3-24 payload to ISS altitude	16,000 kg^R (reported)
H3-30 launch cost	$33.9M^R (reported)
Cost target (any variant)	$50 million per flight^R (reported)
Successful flights (as of Aug 2026)	7 successful, 2 failures, 9 total^R (reported)

^R reported by the company

Update log

6 updates

About Mitsubishi Heavy Industries (MHI)

The team behind H3 Launch Vehicle

Mitsubishi Heavy Industries (MHI)

H3 rocket, launch vehicle, Japan, JAXA, space launch

Mitsubishi Heavy Industries is the prime contractor for Japan's H3 launch vehicle, developed with JAXA. The H3 is a medium-lift rocket targeting 50% cost reduction versus H-2A. Seven successful missions as of August 2026.

MHI is prime contractor for Japan's H3, targeting $33.9M per launch for the H3-30 variant (no solid boosters).
Approved in May 2013, first flight March 2023; seven successful missions by August 2026 after two failures.
H3-24 lifts 7,900 kg to geostationary transfer orbit; H3-30 lifts 4,000 kg to sun-synchronous orbit.

mhi.com (opens mhi.com)Company profile →

Founded: 1884142 yrs
Headquarters: Japan
Status: Public
Valuation: $83Bmarket capSep 2026
Works in: SpaceflightLaunch
Coverage: 1 program · 6 updateslatest 11 Aug 2026checked 10 Oct
Partners: Japan Aerospace Exploration Agency (JAXA) (opens global.jaxa.jp)
Suppliers: IHI Corporation (opens ihi.co.jp)Kawasaki Heavy Industries (opens kawasaki.com)

Spec

H3 Launch Vehicle

H3-30 payload to sun-synchronous orbit

4,000 kg^R (reported)

H3-24 to geostationary orbit

7,900 kg^R (reported)

H3-24 payload to ISS altitude

16,000 kg^R (reported)

H3-30 launch cost

$33.9M^R (reported)

Cost target (any variant)

$50 million per flight^R (reported)

Successful flights (as of Aug 2026)

7 successful, 2 failures, 9 total^R (reported)

H3 Launch Vehicle

Milestones

Most important updates

Upcoming

Current obstacles

Physics limits

How it works

Modular LE-9 engines

LE-5C upper stage

Streamlined design

Spec sheet

Update log

Tue 11 Aug

Fri 12 Jun

Mon 22 Dec 2025

Sun 26 Oct 2025

Sat 17 Feb 2024

Tue 7 Mar 2023

About Mitsubishi Heavy Industries (MHI)

Current obstacles

Physics limits

How it works

Modular LE-9 engines

LE-5C upper stage

Streamlined design

Spec sheet

Update log

Tue 11 Aug

Fri 12 Jun

Mon 22 Dec 2025

Sun 26 Oct 2025

Sat 17 Feb 2024

Tue 7 Mar 2023

About Mitsubishi Heavy Industries (MHI)