What are Solid-fuel Missiles, and Why is North Korea Developing Them?

Hwasong-18 intercontinental ballistic missile is launched from an undisclosed location in North Korea in this image released by North Korea's Korean Central News Agency on July 13, 2023. KCNA via REUTERS
Hwasong-18 intercontinental ballistic missile is launched from an undisclosed location in North Korea in this image released by North Korea's Korean Central News Agency on July 13, 2023. KCNA via REUTERS
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What are Solid-fuel Missiles, and Why is North Korea Developing Them?

Hwasong-18 intercontinental ballistic missile is launched from an undisclosed location in North Korea in this image released by North Korea's Korean Central News Agency on July 13, 2023. KCNA via REUTERS
Hwasong-18 intercontinental ballistic missile is launched from an undisclosed location in North Korea in this image released by North Korea's Korean Central News Agency on July 13, 2023. KCNA via REUTERS

North Korea launched a suspected intermediate-range ballistic missile (IRBM) on Tuesday, in what South Korean officials said could be related to its development of a new solid-fuel hypersonic weapon.
The launch comes after North Korean leader Kim Jong Un oversaw a ground test of a solid-fuel engine for a new type of intermediate-range hypersonic missile to develop national defense capability, state media reported in March.
In January, North Korea test fired an IRBM that it said was equipped with a hypersonic maneuverable controlled warhead. State media did not immediately disclose details of Tuesday's launch.
Here are some characteristics of solid-fuel technology, and how it can help the nuclear-armed North improve its missile systems.
WHAT ARE SOME ADVANTAGES OF SOLID FUEL?
Solid-fuel missiles do not need to be fueled immediately ahead of launch, are often easier and safer to operate, and require less logistical support, making them harder to detect and more survivable than liquid-fuel weapons, reported Reuters.
"These capabilities are much more responsive in a time of crisis," said Ankit Panda, a senior fellow at the US-based Carnegie Endowment for International Peace.
WHAT IS SOLID-FUEL TECHNOLOGY?
Solid propellants are a mixture of fuel and oxidizer. Metallic powders such as aluminum often serve as the fuel, and ammonium perchlorate, which is the salt of perchloric acid and ammonia, is the most common oxidizer.
The fuel and oxidizer are bound together by a hard rubbery material and packed into a metal casing.
When solid propellant burns, oxygen from the ammonium perchlorate combines with aluminum to generate enormous amounts of energy and temperatures of more than 5,000 degrees Fahrenheit (2,760 degrees Celsius), creating thrust and lifting the missile from the launch pad.
WHO HAS THAT TECHNOLOGY?
Solid fuel dates back to fireworks developed by the Chinese centuries ago, but made dramatic progress in the mid-20th century, when the US developed more powerful propellants.
North Korea uses solid fuel in a range of small, shorter-range ballistic missiles, as well as in its new Hwasong-18 intercontinental ballistic missile (ICBM).
The Soviet Union fielded its first solid-fuel ICBM, the RT-2, in the early 1970s, followed by France's development of its S3, also known as SSBS, a medium-range ballistic missile.
China started testing solid-fuel ICBMs in the late 1990s.
South Korea has also said it has secured "efficient and advanced" solid-propellant ballistic missile technology, though in much smaller rockets so far.
SOLID VS LIQUID
Liquid propellants provide greater propulsive thrust and power, but require more complex technology and extra weight.
Solid fuel is dense and burns quite quickly, generating thrust over a short time. Solid fuel can remain in storage for an extended period without degrading or breaking down - a common issue with liquid fuel.
North Korea said the development of its solid-fuel ICBM, the Hwasong-18, would "radically promote" its nuclear counterattack capability.
After the first launch South Korea's defense ministry sought to downplay the testing, saying the North would need "extra time and effort" to master the technology.



Leisure ‘Forgotten’: Gaza War Drives Children to Work

Palestinian children break up stones collected from homes destroyed by previous Israeli air strikes, to sell them to make gravestones, in Khan Younis, southern Gaza Strip, 21 August 2024. (EPA)
Palestinian children break up stones collected from homes destroyed by previous Israeli air strikes, to sell them to make gravestones, in Khan Younis, southern Gaza Strip, 21 August 2024. (EPA)
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Leisure ‘Forgotten’: Gaza War Drives Children to Work

Palestinian children break up stones collected from homes destroyed by previous Israeli air strikes, to sell them to make gravestones, in Khan Younis, southern Gaza Strip, 21 August 2024. (EPA)
Palestinian children break up stones collected from homes destroyed by previous Israeli air strikes, to sell them to make gravestones, in Khan Younis, southern Gaza Strip, 21 August 2024. (EPA)

Some crush rocks into gravel, others sell cups of coffee: Palestinian children in Gaza are working to support their families across the war-torn territory, where the World Bank says nearly everyone is now poor.

Every morning at 7:00 am, Ahmad ventures out into the ruins of Khan Younis in southern Gaza, picking through the rubble produced by steady Israeli bombardment.

"We gather debris from destroyed houses, then crush the stones and sell a bucket of gravel for one shekel (around 0.25 euros)," the 12-year-old said, his face tanned by the sun, his hands scratched and cut and his clothes covered in dust.

His customers, he said, are grieving families who use the gravel to erect fragile steles above the graves of their loved ones, many of them buried hastily.

"At the end of the day, we have earned two or three shekels each, which is not even enough for a packet of biscuits," he said.

"There are so many things we dream of but can no longer afford."

The war in Gaza began with Hamas's unprecedented October 7 attack on southern Israel which resulted in the deaths of 1,199 people, most of them civilians, according to an AFP tally based on Israeli official figures.

Israel's retaliatory military campaign has killed at least 40,476 people in Gaza, according to the Hamas-run territory's health ministry, which does not break down civilian and militant deaths.

The UN rights office says most of the dead are women and children.

"Nearly every Gazan is currently poor," the World Bank said in a report released in May.

- 'Barefoot through the rubble' -

Child labor is not a new phenomenon in Gaza, where the United Nations says two-thirds of the population lived in poverty and 45 percent of the workforce was unemployed before the war.

Roughly half of Gaza's population is under 18, and while Palestinian law officially prohibits people under 15 from working, children could regularly be found working in the agriculture and construction sectors before October 7.

The widespread wartime destruction as well as the constant displacement of Gazans trying to stay ahead of Israeli strikes and evacuation orders has made that kind of steady work hard to find.

Khamis, 16, and his younger brother, Sami, 13, instead spend their days walking through potholed streets and displacement camps trying to sell cartons of juice.

"From walking barefoot through the rubble, my brother got an infected leg from a piece of shrapnel," Khamis told AFP.

"He had a fever, spots all over, and we have no medicine to treat him."

Aid workers have repeatedly sounded the alarm about a health system that was struggling before the war and is now unable to cope with an influx of wounded and victims of growing child malnutrition.

- Money gone 'in a minute' -

The paltry sums Khamis and Sami manage to earn do little to defray the costs of survival.

The family spent 300 shekels (around 73 euros) on a donkey-drawn cart when they first fled their home, and later spent 400 shekels on a tent.

At this point the family has relocated nearly 10 times and struggles to afford "a kilo of tomatoes for 25 shekels", Khamis said.

Moatassem, for his part, said he sometimes manages to earn "30 shekels in a day" by selling coffee and dried fruit that he sets out on cardboard on the roadside.

"I spend hours in the sun to collect this money, and we spend it in a minute," the 13-year-old said.

"And some days I only earn 10 shekels while I shout all day to attract customers," he added.

That's a drop in the ocean for daily expenses in a territory where prices for goods like cooking gas and gasoline are soaring.

In these conditions, "we only think about our basic needs, we have forgotten what leisure is, spending for pleasure," Moatassem said.

"I would like to go home and get back to my old life."