At Hanwha Aerospace, it is rocket science, gimbal mount and all

Tech

Published: 14 May. 2022, 07:00 Updated: 15 May. 2022, 07:23

At Hanwha Aerospace, it is rocket science, gimbal mount and all

Jang Jae-won, an engineer at Hanwha Aerospace, checks rocket engines for Korea Space Launch Vehicle-II (KSLV-II) at the factory in Changwon, South Gyeongsang. [PARK SANG-MOON]

CHANGWON, South Gyeongsang — Rocket engines looking like giant espresso machines in a nondescript industrial building are vital to the Korean space program.

They stand 10 feet tall and are topped by a tangle of wires and tubes punctuated by valves and turbo pumps.

The unnamed 75-ton liquid propellant engines being built by Hanwha Aerospace will power Korea Space Launch Vehicle-II (KSLV-II), also known as Nuri.

It is a domestically designed and manufactured rocket.

Hanwha Aerospace produced a set of liquid fuel engines for a rocket that launched last October. The three-stage vehicle reached the right altitude but failed to place a 1.5-ton dummy payload into the desired orbit.

Another attempt will be made on June 15 with the aim of sending real satellites into orbit this time.

On April 21, the Korea JoongAng Daily toured the Hanwha Aerospace facility where liquid propellant rocket engines being used in the state-funded project are manufactured.

Two 75-ton liquid propellant engines being used in the first stage of the KSLV-II stand at Hanwha Aerospace’s plant. [PARK SANG-MOON]

The engines for the second launch were delivered to the Korea Aerospace Research Institute (KARI) last July as the institute is responsible for integrating them with other parts.

Engines for the third launch were there, displayed beneath the Korean flag.

The upper part of the engine is called the combustion chamber, where oxidizer and fuel are mixed and burned. The propellants are sent through turbo pumps to the chamber from two separate tanks.

The lower body, connected to the combustion chamber, is the nozzle.

A total of 458 steps are involved in making the liquid propellant engines for the Nuri rocket, and 80 engineers have participated in the production of engines for the KSLV-II, according to the manufacturer.

The key difference between the first and the second launch lies in the actual satellites. Albeit small in size, they are being carried instead of the test payload used in the first.

A total of six engines will take the satellites into orbit. Four engines with 75 tons of thrust power the first stage, a single 75-ton-thrust engine powers the second stage and an engine with 7 tons of thrust powers the third stage.

"The design and the structure is the same as the ones used in the first launch since the performance of the engines was successful. So, we focused on following through the same process as safety and credibility were proven from the first launch," said Jang Jae-won, an assistant manager at Hanwha Aerospace.

A test stand is designed to measure the axis of rocket engines. [PARK SANG-MOON]

The failure of the previous mission was not related to the engine. A poorly designed oxidizer tank from local suppliers was found to be the cause.

Still, the manufacturer conducted additional tests for the successive engines to better verify performance in preparing for future launches. The engines are exposed to extreme temperatures — minus 183 degrees Celsius (minus 297.4 degrees Fahrenheit) to 3,300 degrees Celsius — said Jang, who guided the reporter through the production site.

"Take this thermal adhesive tape and the safety wires surrounding hundreds of bolts," he said. "We had to take into account thermal conductivity, weight and other properties related to heat, exhaust and cooling."

Only the United States, Russia, Europe, China, India and Japan are able to send satellites weighing more than one ton into orbit using their own launch vehicles.

Nuri's predecessor was the KSLV-I rocket, which carried the 100-kilogram (220 pounds) satellite into orbit on Jan. 30, 2013 after two failures and several delays.

Even though that was hailed as the first successful launch of a Korean-made space vehicle, the two-stage rocket relied on Russian technologies for the first stage.

To make engines with indigenous technology, engineers had to start from scratch.

"In the beginning, it was really tough," recalled Jang, who is in charge of the architectural design of the gimbal mount. The component acts as a pivot at the top of the combustion chamber.

"My colleagues and I visited factories in countries with advanced technologies sometime in 2014, but that alone was not sufficient to learn what is inside the engines and how the components are structured," he said.

"So, we dug into numerous dissertations, research papers and other materials."

Jang felt proud and emotional during the first launch.

"When engines from each stage separated and reached the targeted orbits, all of us were full of joy and breathed sighs of relief," he said.

Hanwha Aerospace delivered the latest engines for the third launch on May 4.

BY PARK EUN-JEE [park.eunjee@joongang.co.kr]