TOKYO, March 13 (Reuters) - Japan's Space One will

launch its Kairos small rocket on its inaugural trip on

Wednesday, in a bid to become the first private firm in the

country to put a satellite in orbit.

While Japan is a relatively small player in the space race,

the nation's rocket developers are scrambling to build cheaper

vehicles to capture booming demand for satellite launches from

its government and global clients.

Lifting off from Space One's launch pad in western Japan at

11:01 a.m. (0201 GMT), Kairos will carry an experimental

government satellite that can be deployed to temporarily replace

intelligence satellites currently in orbit if they come offline.

Kairos, an 18 m (59 ft) solid-fuel rocket, is designed to

lift a 250 kg payload to low-earth orbit. Space One had

initially planned the launch on Saturday but postponed it after

a ship entered the nearby restricted sea area.

Tokyo-based Space One was established in 2018 by a

consortium of Japanese companies - Canon Electronics ( CAOEF ),

the aerospace engineering unit of IHI, construction

firm Shimizu ( SHMUF ) and the state-backed Development Bank of

Japan. Two of Japan's biggest banks, Mitsubishi UFJ and

Mizuho, also own minority stakes.

Space One wants to offer "space courier services" to

domestic and international clients, aiming to launch 20 rockets

a year by the late 2020s, its president Masakazu Toyoda says.

The company had already delayed Kairos' inaugural launch window

four times but said orders for its second and third planned

trips have been filled, including by an overseas customer.

Space One does not disclose Kairos' launch costs, but

company executive Kozo Abe said that it is "competitive enough"

against American rival Rocket Lab.

Rocket Lab has launched more than 40 Electron small rockets

from New Zealand since 2017 at roughly $7 million per flight.

Several Japanese companies have used Electron for their

missions, including radar satellite makers iQPS and

Synspective, and orbital debris-removal startup Astroscale.

Last month, state-funded Japan Aerospace Exploration Agency

(JAXA) successfully launched its new cost-efficient flagship

rocket H3. JAXA completed a historic "pinpoint" moon landing

earlier this year and the H3 is tasked to carry about 20

satellites and probes to the space by 2030.

In 2019, Interstellar Technologies conducted Japan's first

privately developed rocket launch with its MOMO series, although

without a full-scale satellite payload.

Partnering with the U.S., Japan is seeking to revitalise its

domestic aerospace industry to counter technological and

military rivalry from China and Russia.

The government last year promised "comprehensive" support

for space startups with technology critical for national

security, as it seeks to build satellite constellations to ramp

up intelligence capabilities.

Japan's defence ministry on Friday said it has struck a deal

with Space One to boost its rockets' payload by experimenting

with fuel-efficient methane engines.