A Hollywood writer would love this plot…but it's true. The "largest, most advanced aircraft of its day," modified for a secret research mission, takes off for a flight over the desert. Painted on its nose are the words, "Cosmic Ray Research." The plane ends up at the bottom of one of the largest man-made lakes in the world, Lake Mead, where the wreck becomes a prized find for underwater archeologists.

The plane was a B-29 Superfortress, one of the last built near the end of World War II at the Boeing plant in Wichita, Kansas. This particular aircraft underwent modifications in 1947 to transform it from a weapon of war to a flying laboratory for Project Apollo, a joint Army/Navy Cold War research program.

On July 21, 1948, the aircraft took off from its base in California and headed east over the desert. It was on a special military mission to conduct atmospheric research using a then top secret instrument called the “sun tracker” that was installed on the plane—hence the words "Cosmic Ray Research" painted on its nose. The mission required runs at altitudes ranging from 30,000 feet to "as low as possible."

While the plane was making a low run over Lake Mead, something went awry. The pilot later reported, “The water was very calm. Surface was absolutely smooth,” when the plane struck the surface of the lake. The landing must have been quite a ride for those on board: according to one account, when the plane hit the water, three of the four engines were torn off and the plane "skipped like a stone for more than a quarter mile."

All five men aboard the aircraft escaped into life rafts before the plane sank to the bottom of Lake Mead. The crew members were rescued by local boaters, and the plane remains where it sank, under about 170 feet of water. Its location was an intriguing mystery for over 50 years; its discovery was announced in 2002. According to the park, it is "remarkably intact with the unique design features and structural modifications still visible."

For reasons of safety and protection of the historic bomber, the site is "closed to SCUBA and all forms of underwater diving unless a permit has been issued by the Chief Ranger's office." The combination of the depth of the wreck and the cold water make the location too risky for most recreational divers. Visits to the bottom at this depth are classified as "technical dives," and require special equipment and training.

At various times in recent years, commercial dive operators have held a Commercial Use Authorization (CUA) to conduct guided technical scuba dives at the B-29 site, but no such agreements are currently in place. According to park spokesman Andrew Muñoz, a prospectus for a new CUA is currently undergoing review, and is expected to be advertised for open bidding early next year. If a new CUA is issued, private divers will once again be able to visit the site.

Lest collectors be tempted to attempt something foolish, it should be noted that all known artifacts from the wreck are now in safekeeping in the park's museum collection. Lake Mead National Recreation Area has been legally designated as "custodian of the B29 Superfortress Bomber and all its appurtenances."

The structure of the plane itself—and its remarkable state of preservation in the cold, deep water—continues to be a subject of considerable scientific and historical interest. A $14,000 grant from the National Park Foundation to the park is funding additional research and documentation on the B-29. The underwater portion of that work is part of a continuing project by the NPS Submerged Resources Center (SRC) and will support the ongoing effort to nominate the submerged aircraft to the National Register of Historic Places. The SRC began documenting the plane in 2002.

The National Park Foundation also awarded a grant to Lake Mead NRA and the SRC to conduct additional work on the site to study impacts invasive quagga mussels might be having on the submerged resource. The support from the foundation made it possible for the SRC to share some of the 3-D underwater footage generated from the B-29 site with the visiting public at national dive shows, professional conferences, and special outreach days for children and students, as well as through web video and social media networking sites such as Facebook and YouTube.

Superintendent Bill Dickinson said, “This generous grant from the National Park Foundation will not only assist in efforts related to the nomination but will also help secure additional protection for this valuable cultural resource within the park. The park and the SRC team are thankful the National Park Foundation concurs this resource is an important piece of Cold War history and deserves National Register listing," said Dickinson.