On an island better known for waterfalls than warheads, Kauai has earned a reputation in defense circles for its outsized role in supporting the military, including America’s evolving nuclear arsenal.

But unlike in the contentious public hearings and periodic protests outside the entry gate at the U.S. Army’s Pohakuloa Training Area on Hawaii Island, Kauai’s own role in supporting America’s nuclear weapons stockpile evokes little scrutiny or debate and is all but unknown by most island residents and visitors.

Central to those efforts that benefit the entire stockpile is the Kauai Test Facility, operated by Sandia National Laboratories for the Department of Energy. It’s located inside the U.S. Navy’s Pacific Missile Range Facility at Barking Sands.

In April, between 30 to 40 scientists, engineers and technicians traveled from Sandia Labs to Kauai for the first two of four experimental High Operational Tempo Sounding Rocket, known as the HOT SHOT, launches scheduled for 2019. Two more are slated for August.

Sandia executed the launches in collaboration with the DOE’s National Nuclear Security Administration, conducting experiments on behalf of other DOE national laboratories and the Atomic Weapons Establishment which manufacturers nuclear warheads for the United Kingdom’s Trident missiles.

According to an NNSA spokesperson, the HOT SHOT program provides scientists and engineers responsible for America’s nuclear weapons “the opportunity to demonstrate new technologies and concepts prior to use in the stockpile.”

Data from the tests “will benefit a broad range of weapons systems across all modernization programs,” the spokesperson said by email, allowing the NNSA to more closely align with the 2018 Nuclear Posture Review goal of a “modern, robust, flexible, ready, responsive, and tailored nuclear deterrent.”

Scott Holswade, director of advanced systems and transformation at Sandia, said sounding rockets are a relatively old technology but provide a reliable, simple, inexpensive way to conduct multiple often unrelated experiments in a single launch.  

April’s sixteen HOT SHOT experiments tested technologies for the ability to withstand heat, turbulence, high acceleration, and intense vibration associated with rocket launches. Other tests included zero gravity and conditions that occur upon atmospheric reentry.

HOT SHOT engines burn out within 30 seconds. But the rockets coast approximately 200 miles high and some 220 miles down range before falling back to earth and sinking to the sea floor at a depth of two to three miles.

From launch to splashdown takes 9-10 minutes with much of the data is transmitted by radio telemetry in the first 30 seconds.

Holswade explained that ideally the test facility would launch two rockets back to back in a single day in order to minimize the effort needed to “stand up the range for the day.” That isn’t always possible as weather conditions or other factors interfere.

The majority of HOT SHOT experiments test technologies being considered for future weapons programs, Holswade said. A key aim of the program is to gain competence and confidence in the technology before committing to specific programs. Another goal is to trim the time needed to test and verify new systems, reducing a decade-long development process down to three years.

“What we’re really looking at is future life extension programs that haven’t started in earnest yet,” Holswade said, describing how HOT SHOT is intended to achieve new technologies that may be a decade away from use so that it’s proven and ready for NNSA programs if and when approved by Congress.

“We need to be faster and more agile at what we do,” Holswade said, explaining how Sandia wants to be ready with new technologies to get out “into a deterrence asset (nuclear weapon) if asked for by the nation.”

“I think the range is definitely an asset that’s really working to improve our national security posture and try to do things where we can reduce the time, increase our agility as a nation, be more responsive to what other actors (international adversaries) are doing.”

Why On Kauai?

Sandia has operated the 130-acre test facility as a tenant inside PMRF since it was established in 1962 to support the Atomic Energy Commission’s Operation Dominic, which included high-altitude nuclear tests over the Pacific. Since then facility has supported some 460 launches.

Holswade said the location on Kauai’s west side allows it to avoid flying over heavily populated areas. “Where we launch is a fairly quiet patch of water. There’s not a lot of shipping traffic.”

With a 57-year history on Kauai, the site has all the launch rails, buildings, and other infrastructure in place, reducing potential challenges or variables that could impede experimental launches.

Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, points out that the HOT SHOT program is explicitly described with the same language used in the 2018 revie which focuses on “Great Power competition” against Russia and China, emphasizing “enhanced flexibility and diversity of U.S. nuclear capabilities,” and the development of new low-yield nuclear weapons. 

As the U.S. pursues nuclear modernization programs consistent with the Trump administration’s Nuclear Posture Review, “those programs are part of a long-term and increasingly dynamic nuclear competition with other nuclear-armed states,” Kristensen said in an email.

“There is every reason to believe the facilities in Hawaii are already in the crosshairs of Russian, and perhaps Chinese nuclear missiles, just like U.S. forces are directed against their facilities.”

In April, the NNSA submitted an Environmental Assessment and a finding of “no significant impact for the continued operation of the Kauai Test Facility,” with proposed activities to include “ongoing operations, upgrades to existing facilities and an increase in the size of the launch vehicles to be launched from the site.” The DOE reported receiving no comments on the draft assessment.

NNSA added it will continue to conduct launch activities at the facility and “expand its vertical launch capabilities” in pursuit of its own mission and in support of U.S. missile defense and hypersonic weapons systems.

 And while Hawaii’s role in supporting the life span of America’s nuclear weapons stockpile is rarely discussed by the public, Kristensen notes, “It is certainly important that people in Hawaii are informed about the work that goes on [in] their islands.”