The small rocket Momo 3 is launched from Taiki, Hokkaido, on May 4. (Provided by Interstellar Technologies Inc.)

TAIKI, Hokkaido--The first rocket assembled entirely by the private sector in Japan lifted off from a launch pad here May 4 and reached outer space before landing harmlessly in the Pacific Ocean as planned.

The 9.9-meter-long Momo 3 with a diameter of 50 centimeters was developed by Interstellar Technologies Inc., in which renowned entrepreneur Takafumi Horie has a major stake.

“Outer space is distant. But our rocket managed to get there, reaching an altitude of about 113 km,” Horie, former president of Livedoor Co., an Internet-related service provider, tweeted.

The rocket soared to an altitude of 100 kilometers, regarded as the border with outer space, about four minutes after launch, and continued flying for more than 10 seconds before returning to Earth.

The distance between the launch site and the landing spot was about 50 km.

It cost tens of millions of yen to launch the rocket, which weighed 1,150 kilograms and was powered by liquid fuel.

Capitalizing on the successful launch, Interstellar Technologies plans to develop a new type of rocket named Zero to put a 100-kg satellite in orbit at an altitude of 500 km.

Competition to develop small rockets is intensifying globally. As demand for launches of small satellites grows and the performance of parts improves, the size of satellites is becoming smaller.

At present, several hundred satellites are sent aloft each year, but on large rockets, which each cost at least several billions of yen to launch.

Interstellar Technologies estimates that if the Zero is commercialized, the cost for the launch will drop to less than 600 million yen. It plans to launch a Zero in late 2022 at the earliest.

The company had initially planned to launch Momo 3 on April 30. But immediately prior to launch, liquid oxygen was found to be leaking and the liftoff was postponed.

The launch was put off twice more, to change parts and because of strong winds near the launch site.

Momo 1 was launched in July 2017. About one minute after the launch, communication with the rocket broke off, and it crashed into the sea from an altitude of 20 km.

Momo 2 was launched in June 2018. Immediately after that launch, however, its engine stopped functioning and the body exploded as it fell out of the sky.