Malaysian Airlines Flight 17 fell from the skies over eastern Ukraine on July 17. None of 283 passengers and 15 crew aboard survived. This much is not in dispute.

What is in dispute is ... just about everything else. Who shot down flight MH17? Was it Ukrainian separatists? Was it their Russian supporters, just a few miles distant, across the Ukrainian border? Whoever is guilty, why did they shoot down the plane? And what can be done to prevent tragedies like MH17 from happening again?

The final voyage of Malaysian Airlines Flight MH17. Map: Wikimedia Commons.

The consensus appears to be that MH17 was hit by an SA-11 "Buk" surface-to-air missile launched from the territory of the self-proclaimed Donetsk People's Republic, a breakaway region of Ukraine. The separatists may have thought they were shooting at a Ukrainian military transport, a tactic they have used in the past.

Not everyone agrees with this theory of events. Russian state news service RT, for example, is currently shopping the theory that Ukraine's own military targeted MH17, either with Ukrainian SA-11s, or perhaps by sending a Su-25 fighter jet to shoot down the civilian airliner.

Whichever theory ultimately proves correct (and international investigators are working up an answer as we speak), one question still remains: How can we protect civilian airplanes from missile strikes in the future?

The only thing that stops a bad guy with a missile ...
Here in the U.S., Sen. Mark Kirk (R-Ill.) has argued that the MH17 tragedy illustrates an urgent need to outfit civilian airliners with onboard missile defense systems. 

There are several such systems on the market. The "Guardian", by Northrop Grumman (NYSE: NOC), takes the form of a canoe-sized "pod" that can be affixed to an airplane's belly and marries a missile launch detection system with a high-powered laser. Upon detecting a launch, Guardian fires its laser at the incoming missile, blinding it and causing it to miss its target. Estimated to cost anywhere from $3 million to as little as $1 million per pod (if produced in quantity), Guardians aboard civilian airliners could add as little as $1 to the cost of a plane ticket, according to Northrop Grumman's calculations.

Photo: Northrop Grumman.

The Guardian, and the similar the C-MUSIC airplane defense system developed by Israel's Elbit Systems (NASDAQ: ESLT), aim to defeat the threat posed by shoulder-fired, man-portable anti-aircraft missiles, also known as MANPADS.

Effective at shooting down slow-moving, low-altitude aircraft such as helicopters (or civilian airliners taking off or landing), MANPADS find their targets by homing in on the heat signature from an airplane's engines. Guardian and C-MUSIC take advantage of this fact by blinding the heat-seekers with laser beams.

Cruising at several hundred miles per hour, however, and at a reported altitude of 33,000 feet, MH17 was out of the reach of MANPADS. It must have been struck by a bigger, more advanced, and -- crucially here -- radar-guided missile such as the Russian Buk's SA-11. And that's simply not the threat that Guardian and C-MUSIC were designed to defeat.

Time to aim higher
One system might have a chance of defeating radar-guided missiles such as the SA-11. It's called a Suite of Integrated Radio Frequency Countermeasure, or SIRFC, and defense contractor Exelis (UNKNOWN:XLS.DL) builds it. SIRFC was developed for use aboard U.S. military aircraft such as the CH-47 Chinook, AH-64 Apache, and UH-60 Black Hawk helicopters, and more recently for use on the V-22 Osprey tiltrotor aircraft.

SIRFC's electronic warfare equipment detects missile guidance radar signals and then jams the radar so as to prevent weapons-lock by a hostile missile. Theoretically, if deployed aboard a civilian airliner, such a system might be effective in protecting against radar-guided missiles such as the SA-11.

SIRFC's cost is similar to that of C-MUSIC or Guardian. The Pentagon's Office of Operational Test and Evaluation estimates it at $1.5 million per unit (in 2003 dollars, or $1.9 million after inflation). That's right in line with the $1 million to $3 million cost of a Guardian or C-MUSIC system -- suggest that widespread adoption of this defensive system might similarly add only about $1 per flight to the price of a plane ticket.

Will airlines adopt these systems?
Earlier this year, we told you about how Israel tapped C-MUSIC to provide on-plane missile defense for all of Israel's commercial airlines. At the time, only one C-MUSIC system was known to have been installed aboard an El Al airplane. But now, Elbit tells me that El Al has installed six of the systems aboard its planes.

What's more, according to Elbit, a C-MUSIC pod that's attached to one plane can be detached and shifted to another plane if necessary -- if for example the one plane is flying a low-risk route, but the other plane is about to fly to more dangerous locales. This ability to shift pods around from plane to plane holds the potential to reduce the cost of outfitting an airline's fleet with missile protection.

Photo: Elbit Systems.

And the time needed to move a pod from one plane to another? About one hour.

Caveat flyer
Still, such systems may not see widespread adoption if airlines, always cost-conscious, opt not to install them. American Airlines (NASDAQ:AAL), for one, is on record opposing "installing counter-MANPADS on commercial aircraft." Other airlines have complained that the systems "add weight, and can weaken the plane's aerodynamics," and that they're "costly." 

And it's true: not every route airplanes fly is at risk of being attacked by sophisticated, radar-guided missiles -- or even the shoulder-carried variety. So the airlines' reluctance to burden their balance sheets with superfluous costs for missile defense systems is to some extent understandable.

It's easy to see, though, how passengers might look at the extra $1 price tag, and think it a bargain for peace of mind it buys.

For the time being, Israeli air travelers alone enjoy the protection of C-MUSIC. Will American air travelers ever be able to say the same?

Air travelers can't help being a little nervous, knowing there are missiles like these down on the ground -- and that they're pointed "up." Photo: Wikimedia Commons.