WASHINGTON — XCOR Aerospace, a company developing rocket engines and a suborbital spaceplane, has laid off its remaining employees but is continuing efforts to raise funding to maintain at least some of its projects.

In a statement provided to SpaceNews July 5, Michael Blum, a member of the company’s board of directors who is also serving as acting chief executive, said some “critical” employees would be retained as contractors as the company attempts to stay alive.

“Due to adverse financial conditions XCOR had to terminate all employees as of 30 June 2017,” Blum said in the statement. “XCOR management will retain critical employees on a contract basis to maintain the company’s intellectual property and is actively seeking other options that would allow it to resume full employment and activity.”

Blum did not disclose how many employees were laid off or how many would be kept on as contractors. In May 2016, XCOR laid off nearly half of its 50 to 60 employees as it devoted its resources to a liquid hydrogen/liquid oxygen engine the company was developing under contract with United Launch Alliance.

At that time, XCOR said it was suspending work on Lynx, a two-seat suborbital spaceplane the company had been working on for several years to serve the space tourism and research markets. Company officials said earlier this year that XCOR had not entirely abandoned the Mark 1 prototype vehicle that had been under construction at its Mojave, California, facility.

“Although we have advanced the program with much of our recent efforts, completion of the prototype is funding dependent,” Marco Martinez-Venturi, head of astronaut relations at the company, told SpaceNews in March.

With its employees laid off, company sources say management and investors are working to save at least some of XCOR’s products, keeping the company from folding entirely.

The company is also without a permanent chief executive. Jay Gibson, hired as chief executive in March 2015, left the company at the end of June. The Trump administration nominated Gibson June 16 to be the Deputy Chief Management Officer at the Department of Defense.

Blum, the acting chief executive, formerly was chief financial officer and a co-founder of Firefly Space Systems, a company that was seeking to develop a small launch vehicle. That company furloughed its staff in September 2016 after a planned funding round fell through. In March, it announced the sale of “virtually all” of its assets.

XCOR’s decision to lay off its remaining employees could also jeopardize a $10 million financial incentive package it received in 2012 to move the company to Midland, Texas. Brent Hilliard, chairman of the board of the Midland Development Corporation, which provided the incentive package, told the Midland Reporter-Telegraph that the board will meet with XCOR July 6 to discuss the company’s status.