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  • Ari Sacher

David's Sling Wins Israel Defense Prize

Updated: Jun 10

Israel Update – Week of May 26, 2024

David’s Sling: On Friday, I got a blast from the past. An old friend, Adam, sent me a WhatsApp message wishing me a “Mazal Tov (Congratulations)!” David’s Sling Weapon System (DSWS) had won the coveted Israel Security Prize. The “Israel Defense Prize,” also known as the “Israel Defense Award,” is an award presented annually by the President of Israel to the people and the organizations who have made significant contributions to the defense of the State of Israel. Usually between three and four systems win the award each year. Previous winners include prestigious systems such as the Iron Dome, the Ofek spy satellite, and an array of still-secret programs. This year’s winners included the “Namer (Tiger)” Armored Personnel Carrier (APC), the 'Target Factory' project, developed by the Air Force, and, of course, DSWS.

Adam and I were involved in DSWS from its inception. As opposed to Iron Dome, which was developed completely in-house, DSWS was, from the outset, cooperatively developed by a partnership between Israel’s RAFAEL and the American Raytheon Missile Systems (RMS), now known as RTX. Adam was the Program Manager for RMS, and I was responsible for managing RMS. While both of us moved on from the program after five or so years, we have remained good friends. In May last year, I sent Adam a picture of the first operational DSWS intercept. Last week Adam returned the favor, sending me a picture of the DSWS team – RAFAEL, RMS, and representatives of the Israeli Missile Defense Organization (IMDO) and the Missile Defense Agency (MDA), who jointly manage the program. The picture was taken at RMS about fifteen years ago. Needless to say, we all looked significantly younger. 

DSWS Team - 2009

While DSWS has been operational since 2016 and while its first operational intercept did not occur for another seven years, the system has been critical in defending the Home Front since October 7. It has been operating with stellar performance and has saved hundreds, if not thousands of lives. It was “natural” to win the Israel Security Prize this year.

DSWS, like nearly every other missile defense system in the world, consists of four basic components: 

[1] a radar (DSWS uses the same ELTA EL/M-2084 Multi Mode Radar as Iron Dome), 

[2] a Battle Management Center, 

[3] a launcher (the DSWS launcher carries up to twelve missiles. The Iron Dome launcher carries up to twenty), and 

[4] the heart of the system: an interceptor.  

So how does DSWS differ from other missile defense systems like Iron Dome? Missiles are, in some ways, similar to baseballs. The further you want to throw a baseball, the higher and faster it must be thrown. Conversely, the higher and faster the baseball flies, the more difficult it is to catch. (This is why baseball players use leather gloves). 

In a similar vein, missiles raining in from Gaza, which is right next door to Israel, fly much slower and lower than missiles launched from Iran, about a thousand miles away. As a result, Gazan missiles are significantly easier to intercept than ones launched from Iran. Unsurprisingly, intercepts of Iranian missiles cost significantly more. An interceptor that shoots down Gazan “Katyushas” can cost an order of magnitude less than one that shoots down Iranian “Gadrs.” To get the most bang for the buck, Israel protects herself with a multi-layer missile defense system, where each layer addresses a different family of threats. Iron Dome takes care of rockets launched from up to a distance of about forty miles. Anything with a longer range will be in the bailiwick of DSWS. Arrow-2 and Arrow-3 are responsible for even longer-ranged threats – Arrow-3 actually intercepts rockets in outer space.

Because DSWS intercepts targets that move significantly faster than Iron Dome targets, it intercepts them with a completely different paradigm. Iron Dome intercepts its target by flying close to the threat and detonating its own warhead (the “pointy end of the stick” i.e. the part of the missile that explodes) in close proximity to the threat with the goal of detonating the threat’s warhead. An Iron Dome interceptor is essentially a truck that carries a large warhead from Point A to Point B. Imagine that you’re in an airport rushing to catch a particularly tight connection. Now imagine that you’re pulling a piece of carry-on luggage packed by your wife that, thankfully, was not weighed when you checked in. Your speed will be limited by the weight of that piece of carry-on luggage you are dragging around. Now imagine that instead of a large carry-on trolley, you have managed to fit everything into a smaller backpack. You will be able to run much more quickly. Finally, imagine that you don’t have any carry-on luggage at all. Perhaps you’re on a day-trip or perhaps the airline has lost all your luggage (More likely the latter). Now your ability to sprint to catch your flight will be limited only by the speed in which your legs can carry you. This is DSWS. A DSWS interceptor (known as “Stunner) does not even have a warhead. This reduces its weight and simultaneously offers serious increases in both range and agility. So how does Stunner intercept its target if it doesn’t have a warhead? It does this by ramming into the threat’s warhead at high speed. This is known as “Hit To Kill (HTK)” performance. It bears repeating that Stunner must not only impact the target, it must impact the target’s warhead, which could be less than a foot long, when both the threat and the interceptor are flying at about a mile a second. Hence the Israel Security Prize.

How does Stunner manage to attain HTK performance? Stunner has a number of technological breakthroughs but two of them stand out: dual steering, which gives it agility, and multi-pulse propulsion, which gives it speed. A missile steers itself similar to an automobile. Whereas an automobile has wheels, a missile has fins. Just like an automobile has front and rear wheels, most missiles have forward (front) and aft (rear) fins. Like an automobile, most missiles steer using their forward fins. Imagine that you are trying to get into a tight parking spot, only slightly longer than the length of your car. It’s going to take some intricate steering and lots of back-and-forth maneuvering to get into that parking space. Now imagine that you have a car in which both wheels turn. All you have to do is line yourself up parallel to your parking space, turn your wheel hard to the right, and the car will simply slip into the parking space. (All-Wheel Steering (AWS) was offered in the 1980s on high-end cars. They were pricey, difficult to control, and even more difficult to maintain. AWS has all but gone the way of the Edsel). Stunner has similar dual steering, in which both the forward and aft fins move, offering it unparalleled agility, and enabling it to impact within inches of where it is programmed to impact.

After solving the agility problem, our next problem is how to get Stunner as far as possible as quickly as possible. Most missiles have a solid rocket motor. The motor is ignited. Then, it burns until all the propellant has been expended and the motor burns out. Lastly, the missile glides the rest of the way to the target. This creates two problems: First, just when the missile needs the most speed, at the “end game,” it is literally running out of breath. Second, when the missile’s rocket motor is fired, the missile quickly reaches a maximum velocity where it can go no faster because of wind resistance. (An automobile’s maximum velocity is determined by wind resistance and, believe it or not, by the friction of the tires on the road). Stunner addresses these problems by separating the rocket motor into individual “pulses.” Stunner flies via a series of “pulse-glide” in which the missile accelerates and then glides. The final pulse is ignited a few seconds before impact so that the missile can accelerate and impact the target at full force. The rocket pulses are timed by a computer in order to achieve maximum range and velocity.  Between dual steering and multi-pulse propulsion, Stunner has unparalleled range and performance. If Iron Dome can defend a “city-sized” area, David’s Sling can defend a far larger area. Here is an example: One Iron Dome battery is required to defend a city the size of Tel Aviv or Jerusalem. In 2023, DSWS interceptors launched from one launcher intercepted threats over both Jerusalem and Tel Aviv. 

DSWS requires biting-edge technology in order to accomplish its mission at a “reasonable” cost. The fact that DSWS meets its admittedly insane mission requirements is tribute to the engineers at RAFAEL and RMS. The Israel Security Prize is a most well-deserved award. 

I am proud to have played even a small part.

Good Things,

Ari Sacher

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