Rockets of Today

KSLV / NARO (나로) / NURI (누리) — South Korea, 2013

KSLV-II / Nuri

When North Korea started working on their Unha satellite launcher, the South Koreans knew that it would not do to be shown up by the north, so they started working on one of their own. They tried to make an entirely domestic rocket but then cheaped out in order to finish quickly, and just imported a kerosene/lox booster — an Angara core purchased from Russia. An early Angara prototype, rather — it had a lower trust engine than the final version. Because this booster was larger than originally planned, their solid second stage now seemed undersized on top of it. This rocket was first called KSLV-1 for Korean Satellite Launch Vehicle, but then they changed the name to Naro-1, taking the name of the island where their launch pad was built.

There were only three launches of the Naro. The first was sent up in 2009, and fell back from space when the fairing failed to open. The second, in 2010, fell apart halfway through the first stage burn. Finally in 2013 the rocket got a satellite into orbit, about a month late to beat the North Korean program, which had also failed its first two attempts (but claimed that they were all successful). They had hoped to get some engineering secrets of the Russian staged-combustion engines out of this deal, but the Russians kept a tight lid on that.


The Naro-1 was then retired — after having checked off the necessary national achievement, they decided using Russian castoffs was not the long term strategy they wanted to follow. They resumed work on putting together an entirely domestic rocket. The result was the Nuri ("World"), or KSLV-II. Its first test launch was in 2021, with only a mass simulator for payload. This test fell a bit short when the third stage shut down prematurely, apparently due to a helium tank shaking loose. The second attempt reached orbit in 2022.

The Nuri is bigger than the Naro, and has three stages where Naro had two. The booster burns kerosene — or rather, cheap jet fuel — and lox, in four “KRE-075” gas generator engines. The second stage uses a single KRE-075 with a vacuum bell. It has a steerable gas generator exhaust pipe which gives it roll control. The third stage uses a much smaller “KRE-007” engine, burning the same fuel. This makes it capable enough to do more than just smallsats, unlike any of the North Korean or related Iranian designs, with a low orbit capacity well over two tons — a size range that’s rather underserved now, as most people seem to have goals that are either under one ton or over six. Their most direct competitor is probably India’s PSLV.

A small suborbital rocket using a single KRE-075 engine was launched as a test in 2018.&ensp It was called the "KSLV-II TLV". They say they plan to use this in the future to launch little satellites, once they give it a second stage.

Further plans include upgrading the Nuri to be able to reach geosynchronous orbit, and eventually the moon. To do this they will develop an improved engine called KRE-090, and use four of them on the core, then add four side boosters with one KRE-090 apiece. The second stage will get a KRE-090V (the large bell version), and they plan to give the third stage a staged-combustion engine, to be called KRE-010V.

Or that might all get dropped, as they are also starting a parallel effort to make a reusable methane burning launcher for midsize payloads.

And in late 2023, the military has tried out a small solid-fuel launcher which we know almost nothing about — not even a name other than Solid Fuel Space Launcher (SFSL). The article flown may have been an interim prototype, as they dubbed it Test Vehicle 2, but it put up a satellite. (Test Vehicle 1 was suborbital.)

Meanwhile, a small South Korean company called Perigee Aerospace is trying to build a rocket so tiny that the Nuri could lift it as a payload. See the Blue Whale article.

Naro-1: mass 140 t, diam 3.0 m, thrust 1670 kN, imp 3.3 km/s, staged combustion (kerosene), payload unknown, cost unknown, record 1/0/2 (final).

Nuri: mass 200 t, diam 3.5 m, thrust 2940 kN, imp 3.1 km/s, gas generator (kerosene), payload 2.6 t (1.3%), cost unknown, record 2/1/0 through 2023. SFSL: mass unknown, diam unknown, thrust unknown, imp unknown, solid fuel, payload unknown, cost unknown, record 0/1/0 through 2023.