Rocket science, it should come as no surprise, is not easy or cheap.

That was most recently demonstrated Jan. 31 off Kauai when a Raytheon SM-3 Block IIA missile failed to intercept an air-dropped intermediate-range target missile. The missile soon will be deployed to Navy ships, Japan, Romania and Poland to defend against North Korean and Iranian threats.

According to the U.S. Missile Defense Agency, which conducted the test, the cost of the still-in-development missile was $36 million.

The cost of the intermediate-range target missile: about $40 million.

Total cost of the test: about $130 million.

The last figure includes Pacific Missile Range Facility use, a variety of radars and other sensors, and about 350 personnel who supported the test, according to the agency.

“This was a developmental and operational test of a new capability and utilized a missile variant not yet in production,” Lt. Gen. Sam Greaves, head of the Missile Defense Agency, said after the test.

Some firsts included using both ground- and space-based sensors to remotely cue the launch of the interceptor missile, Greaves said. It was also the first time an SM-3 IIA missile was launched from land using the Aegis Ashore test complex on Kauai.

Everything up to and including the launch worked. A failure review board will determine why an intercept didn’t occur.

The costs, meanwhile, point to the fact that the United States spends a lot of money on a missile defense system that’s still very much a work in progress.

The Missile Defense Agency is requesting $9.9 billion in fiscal 2019. According to a May 2017 U.S. Government Accountability Office report, the agency since 2002 has received approximately $123 billion to develop and deliver ballistic missile defense systems.

U.S. officials repeatedly express confidence in the 44 ground-based interceptors in Alaska and California that protect Hawaii and the mainland from North Korean threats.

The mainly ship-based Aegis ballistic missile defense system, which uses multiple types of missiles, has a test record of 36 successful intercepts in 45 tries, according to the Congres­sional Research Service.

A new SM-3 IIA also failed to hit its target in June off Kauai. A sailor on the Pearl Harbor destroyer USS John Paul Jones, which was doing the shooting, pushed a button that caused the missile to self-destruct in flight in a $130 million mistake.

Usually, the nation’s obstacles to ballistic missile defense have to do with extreme physics challenges that are likened to a bullet hitting a bullet in space — which makes for an expensive interceptor.

The over-the-horizon Raytheon/Kongsberg Naval Strike Missile, a long-range, precision strike weapon that can destroy enemy ships at distances up to 115 miles, flies at sea-skimming altitude, uses an advanced seeker for targeting and costs about $1.5 million, according to published reports.

David Wright, co-director and senior scientist with the Global Security Program at the Union of Concerned Scientists, said the three-stage SM-3 IIA is significantly larger and faster than the Naval Strike Missile. The SM-3 IIA has a range of 1,350 miles or more.

“In particular it has a speed 15 times that of the Naval Strike Missile (4.5 kilometers a second versus 0.3 kilometers a second), which means that it is very different technology and much more expensive,” Wright said in an email.

Similarly, the target missiles used for the intercept tests have a speed of several kilometers a second, “so you would expect the price to be similar,” he said.

The SM-3 IIA, which is 21 feet 6 inches long, is initially aimed at downing short- to intermediate-range missiles, but the Missile Defense Agency said it may be capable of intercepting intercontinental ballistic missiles.

The SM-3 deploys a “hit-to-kill” interceptor that collides with an enemy warhead. An ICBM tears through space, at times reaching more than 15,000 mph, or almost 20 times the speed of sound. Kinetic energy interceptors can create closing speeds in excess of 25,000 mph.

Ballistic missile defense interceptors “are disproportionately expensive due to the demands of hit-to-kill, seekers, infrared sensors, divert thrusters, etc. All of these elements need to be carefully integrated to ensure very high reliability,” said Kingston Reif, director of disarmament and threat reduction policy at the Arms Control Association.

“The margin for error — both in terms of time and distance — is incredibly small,” he said.

The Missile Defense Agency said while the developmental SM-3 IIA missile used in the Jan. 31 test cost $36 million, production missiles will be about $25 million.