KSR Korea Sounding Rocket

As a part of the Korea National Space Program, the Korean government led the Korea Sounding Rocket [KSR] Program during 1993-2002. The Korea Aerospace Research Institute (KARI) provided enhanced capabilities across a spectrum of earth sciences and/or astrophysics-related disciplines. This program includes Korea Sounding Rocket (KSR)-I, KSR-II, and KSR-III, and a total of five soundings were carried out. Two had flown in KSR-I series, two in KSR-II, and one in KSR-III. The main mission objective is to provide the opportunity to scientists for researching earth sciences and/or astrophysics and to improve Korean rocket development technologies including payload instruments, flight systems, ground systems, operational techniques, and interfaces between subsystems. As demand increased for launching of low-orbit earth satellites internally and externally, the Korean government was ambitiously firing the Korea Space Launch Vehicle (KSLV) Program in 2002, based on experience throughout the Sounding Rocket Program and preparing the world market for space launch vehicles.

KSR-1

The ROK successfully launched its first ever scientific research rocket, the KSR-1 in 1993.Korea Aerospace Research Institute (KARI) embarked on a research and development program for the scientific rocket, KSR-I (Korea Sounding Rocket-I) in 1990, which was the first domestic single-stage unguided solid-propellant scientific rocket with a length of 6.7m, a diameter of 0.42m and lift-off weight of 1.2tons.

KSR-I was launched on June 4 and September 1, 1993, respectively carrying an ultraviolet radiometer with the mission to measure the vertical ozone distribution in the stratosphere over the Korean peninsular. Temperature, acceleration and the other parameters were also measured to examine the performance of the rocket throughout the test flights. KSR-I had the payload capacity of 150kg and could reach the altitude of 75km.

Two stratospheric ozone profiles have been obtained using rocket-based solar absorption UV radiometry over Anheung, Korea on June 4 and September 1, 1993. The ozone sensor consists of four radiometers, measuring the attenuation of solar ultraviolet radiation as a function of altitude during ascent. The retrieved ozone density profiles cover altitudes of 15 to 35 km from the first sounding Korean Sounding Rocket-1 (KSR-1 ) and 15 to 45 km from the second sounding (KSR-2). Retrieved profiles have random errors (1s) of approximately 7% for altitudes between 20 and 30 km for KSR-1 and between 20 and 40 km for KSR-2 and ~15-20% for other regions. Both profiles compare reasonably well with near-coincident ground-based lidar and Umkehr measurements as well as with satellite measurements of the Halogen Occultation Experiment on board UARS. The KSR-1 and KSR-2 soundings provided the first near in situ measurements of ozone concentrations over the Korean Peninsula.

The Korea Sounding rocket KSR 420S main purpose was to measure ozone concentration profiles over Korea; the KSR 420S was used further to deliver some instruments such as an ionospheric device and a micro gravity measuring device. The performance of KSR 420S rocket for maximum altitude and maximum scientific payload weight were around 75Km and around 30Kg respectively. The rocket was 6.7 meters in length, had a single stage, and could reach an altitude of 75 km. Jane's Strategic Weapons Systems states that ROK could modify the KSR-1 to a ballistic missile to carry a 200 kg payload a range of 150 km.

KSR-2

KSR-II was a 2-stage solid propellant scientific rocket developed for the scientific experiments at the upper atmosphere. Based on the experience acquired through the development and launch of the single stage rockets, KARI was able to build the KSR-II, powerful enough to reach the altitude of maximum 150km and beyond. The rocket has a length of 11.04m, a total weight of 2tons, and a diameter of 0.42m. It measured the vertical distribution of ozone by using ultraviolet radiometer.

On July 10, 1997, the ROK test launched its first independently developed science rocket, the KSR-2. According to reports from The Korea Herald, the rocket is 11.1 meters in length, has two launch stages, and weighs approximately two tons. On its initial test flight, the rocket carried a 150 kg scientific observation unit to an orbit of 151.5 km. unclassified literature, however, does not indicate if the payload went into orbit. Although the South Koreans have not given any indication that they will convert the KSR-2 into a ballistic missile, Jane's Strategic Weapons Systems notes that, "unconfirmed reports suggest that a secondary use might be for a series of ballistic missiles with ranges from 100 to 900 km."

The literature of the late 1990s suggested that the KSR-2 program is a step toward a South Korean space launch program. According to an article published in Jane's International Defense Review Extra in February 1997, South Korea was developing a three-stage version of the rocket that may be completed by 1999. There is no information in the unclassified literature, however, specifying the potential range of this rocket if converted into a ballistic missile.

An X-ray observation system was developed at Korea Astronomy Observatory for 3 years (1995-1997). The instrument, which is composed of detector and signal processing parts, is designed for the future observations of compact X-ray sources. The performance of the instrument was tested by mounting on the two-stage Korean Sounding Rocket, which was launched from Taean rocket flight center on June 11 at 10:00 KST 1998. Telemetry data were received from individual parts of the instrument for 32 and 55.7 sec, respectively, since the launch of the rocket.

KSR-III

Korea was developing a small launch vehicle with the aim of lifting a several-hundred kg multi-purpose satellite within a decade. KARI (Korea Aerospace Research Institute) has developed a 13-ton thrust liquid propellant sounding rocket, KSR-III (Korea Sounding Rocket-III). Its development phase progressed according to the MM (Miniature Model), EM (Engineering Model), PM (Prototype Model), and FM (Fight Model) models.

KARI embarked on its first liquid-fuel rocket project in December 1997. KARI developed a liquid propulsion rocket system, KSR-III incorporating core technologies for the satellite launch vehicle such as in propulsion, guidance/control, mission design, etc. On November 28, 2002, KARI successfully launched KSR-III, in Anheung Proving Ground, 160 km southwest of Seoul. It reached an altitude of 42.7km and flew over 84 km. This project can be considered a preparatory step towards a satellite launch vehicle development.

The KSR-III used a pressure-fed type liquid rocket engine system with gaseous helium as a pressurant, LOX (liquid oxygen) and kerosene as a propellant. The purpose of propulsion feeding system is to feed the certain amount of propellant from propellant tank to combustion chamber manifold inlet during combustion. Pressure-fed liquid rocket, KSR-III has the characteristic of feeding system with both pressure regulator and venturi as a flow control device. To feed constant mass flow rate of propellant at the engine inlet, pressure regulators are used for helium pressurant system and venturi - passive flow control device - is used in propellant feeding system. KSR-III flight test is succeeded with developing this feeding system that have a simple configuration and small quantity of operation parts. Propellant feeding system has to feed propellant at the engine inlet during combustion with constant propellant mass flow rate. The active flow control device is not adopted in KSR-III propulsion system. Pressure distribution from the propellant tank to combustor was determined by CFD method, FlowMaster.

In the case of KSR-III, the pressure of combustion chamber has changed abruptly from ambient to 200 psi during ignition period. According to this pressure difference, the propellant flow rate inflowed to combustor can be changed greatly in this period. This may cause feeding system instability. To control this phenomenon, venturi is applied to propellant feed line; it is possible to accomplish the propellant feeding system with almost constant propellant flow rate during the change of combustor pressure.

Janes reports that a three-stage KSR-3 rocket. capable of reaching an altitude of 350 km, was planned for development. Unconfirmed reports suggest that a secondary use for these rocket development programmes might be for a series of ballistic missiles with ranges from 100 to 900 km and that the first in this series would be KSR-1 (or KSR-420).