Scientists at Sandia National Laboratories are claiming success with the first in a new series of test flights involving an upgraded version of a nuclear bomb that has been part of the U.S. arsenal for decades.

Work on the B61—12 has been ongoing for years, and government officials say the latest tests using mock versions of the bomb will be vital to the refurbishing effort.

An F-16 from Nellis Air Force Base dropped an inert version of the weapon over the Nevada desert last month to test its non-nuclear functions as well as the plane’s ability to carry the bomb.

With a mere puff of dust, the mock bomb landed in a dry lake bed at the Tonopah Test Range.

“It’s great to see things all come together- the weapon design, the test preparation, the aircraft, the range and the people who made it happen,” Anna Schauer, director of Sandia’s Stockpile Resource Center, said in a statement.

Scientists are planning to spend months analyzing the data gathered from the test.

Tracking telescopes, remote cameras and other instruments at the test range recorded information on the reliability, accuracy and performance of the weapon under conditions that were meant to replicate real-world operations.

More test flights are planned over the next three years, and officials with the National Nuclear Security Administration said the first production unit of the B61-12 developed under what is called the Life Extension Program is scheduled to be completed in 2020.

The B61-12 consolidates and replaces four older versions in the nation’s nuclear arsenal. It’s outfitted with a new tail-kit assembly and other hardware.

The weapon is much different than the non-nuclear “mother of all bombs” used in Afghanistan this week to attack an Islamic State stronghold near the Pakistani border. The Massive Ordnance Air Blast bomb, or MOAB, isn’t designed to penetrate like the B61-12 but rather create a large blast over the surface and it has to be ferried by a much larger plane given its size.

In Nevada, it took two passes before the pilot could drop the mock B61-12. A herd of wild horses had to be chased away on the first go-around.

With the run commencing, people gathered on balconies at the range despite knowing they would see only dust rising from the target miles away. A video feed showed the test bomb fall through the air after being released by the F-16.

Officials said it left behind a rather neat hole. Crews were able to dig the mock weapon out of the dirt so it could be packed up and returned to Albuquerque for further study.