Two people connected to the development of a critical aerospace material known as Mondaloy — an alloy used in advanced rocket engines — have disappeared in separate incidents, raising questions about a pair of unusual and currently unexplained missing-person cases.
Authorities say aerospace engineer Monica Jacinto Reza vanished in June 2025 while hiking in Southern California, and retired U.S. Air Force Maj. Gen. William Neil McCasland disappeared in February 2026 after leaving his home in Albuquerque, New Mexico.
Both were connected through their roles in the development and government funding of Mondaloy, a material designed to help the United States reduce reliance on Russian rocket technology.
Investigators have not publicly linked the two disappearances, and officials say each case is being treated as an individual missing-person investigation.
What Mondaloy is — and why it matters
Mondaloy is a nickel-based superalloy designed to withstand extreme heat and oxygen-rich environments inside rocket engines, particularly in components exposed to intense combustion. The material was developed through aerospace research partnerships involving industry engineers and U.S. government laboratories.
Such alloys are critical for engines that use oxygen-rich staged combustion, a design historically mastered by Soviet and Russian rocket programs but difficult for American manufacturers to replicate due to material limitations. Mondaloy helped address that challenge by producing metal components that resist burning and cracking under the extreme temperatures and pressures found in rocket preburners and turbines.
The material has been used in testing and development of U.S. rocket engines intended to replace the Russian RD-180, which powered several American launch vehicles for decades.
After geopolitical tensions and sanctions strained access to Russian hardware, U.S. aerospace firms and defense agencies accelerated development of domestic alternatives.
The disappearance of Monica Reza
Reza, an aerospace engineer who spent decades working in rocket propulsion materials, was reported missing on June 22, 2025, while hiking in the Angeles National Forest in California. According to accounts cited in investigative reports, she was hiking with a companion and was last seen waving from a ridgeline roughly 30 feet behind him before disappearing from view.
Search crews, including helicopters and rescue teams, scoured the area but reportedly found no definitive trace of her. The disappearance drew attention in aerospace circles because Reza had helped develop Mondaloy and held patents for burn-resistant high-strength alloys used in rocket engines.
At the time she vanished, Reza had spent years working with aerospace contractor Aerojet Rocketdyne and had also been connected to research programs involving NASA’s Jet Propulsion Laboratory.
The disappearance of Neil McCasland
Eight months after Reza’s disappearance, McCasland, 68, went missing from his home in Albuquerque on Feb. 27, 2026, according to local law enforcement. Officials say McCasland left his residence sometime that morning. He reportedly left behind personal items, including his phone and glasses, and he has not been seen since. McCasland’s firearm remains “unaccounted for.”
McCasland previously commanded the Air Force Research Laboratory (AFRL), the organization responsible for developing and funding advanced aerospace and defense technologies. During his tenure, AFRL oversaw programs supporting propulsion materials research, including work related to alloys like Mondaloy.
Search efforts have involved local authorities, search-and-rescue teams, and federal agencies, but investigators have not announced any confirmed sightings or discoveries explaining his disappearance.
For now, authorities emphasize that both disappearances remain open investigations, and no official evidence has suggested a connection beyond their professional involvement in aerospace programs.
Published: Mar 18, 2026 03:54 pm