WASHINGTON — SpaceX announced April 27 it plans to send an uncrewed Dragon spacecraft to the surface of Mars as soon as 2018 on a technology demonstration mission aided by expertise, but not funding, from NASA.

The company said it planned to launch a Dragon 2 spacecraft dubbed “Red Dragon” to Mars on a Falcon Heavy launch vehicle as soon as the next launch window for Mars missions, which opens in the spring of 2018. The company released few other details about that proposed mission, including its cost and funding source.

“Red Dragons will inform overall Mars architecture, details to come,” the company said in a tweet accompanied by illustrations of a Falcon Heavy launch and a Dragon spacecraft resting on the Martian surface. The “overall Mars architecture” appears to refer to SpaceX Chief Executive Elon Musk’s long-term vision of establishing a permanent human presence on Mars.

“Dragon 2 is designed to be able to land anywhere in the solar system,” Musk tweeted April 27. “Red Dragon Mars mission is the first test flight.”

The Red Dragon concept, using a relatively unmodified version of the Dragon spacecraft to land on Mars, is not new. Studies of the Red Dragon concept date back to early this decade, when SpaceX and a NASA team based primarily at the Ames Research Center jointly examined the idea of using a Dragon spacecraft to land on Mars and carry science equipment.

“Dragon launched on Falcon Heavy would be a cost effective option for future missions,” concluded an October 2011 report prepared by the NASA/SpaceX team on that initial Red Dragon study. It concluded that Dragon would be able to handle all aspects of entry, descent and landing (EDL) on Mars “with margin,” and deliver more than one metric ton of payload to the surface. That is more than the mass of the Curiosity rover NASA landed on Mars in 2012.

A key element of the Dragon design that would allow it to land on Mars is its SuperDraco thruster system, which SpaceX developed for the Dragon 2, or Crew Dragon, spacecraft to serve as a launch abort system. SpaceX envisions using the thrusters to also permit powered landings of the crewed Dragon on Earth, deploying small landing legs from the base. The same system would be used to slow the spacecraft through the Martian atmosphere and land on the surface.

Industry sources said work on the Red Dragon concept picked up after SpaceX won a Collaborations for Commercial Space Capabilities (CCSC) award from NASA in December 2014. The unfunded Space Act Agreement gave SpaceX, among several other companies, access to NASA technical expertise to pursue advanced concepts.

The original CCSC agreement between NASA and SpaceX offered few details beyond work in two areas “to support missions to Mars and ultimately enable humans to live on Mars.” One area covered EDL technologies for Red Dragon and other subsystems specific to deep-space operations. The second area covered technology for using Martian resources, such as producing methane and oxygen propellants, and “human-scale” EDL technologies. That work was scheduled to be completed by March 2017, but made no mention of a Red Dragon mission itself.

An amended agreement, signed by SpaceX and NASA officials April 25 and 26, respectively, replaces the original schedule with a mission-oriented one, with milestones tied to the launch and landing of a Red Dragon mission. The specific date for the mission itself, though, is not mentioned.

The scope of cooperation is also expanded to cover topics such as planetary protection and “general interplanetary mission and hardware consultation and advice.” The revised agreement replaces semi-annual reviews between NASA and SpaceX with quarterly ones, suggesting a faster pace of work.

The agreement does not mention what the Red Dragon mission would do, although the agreement includes language covering the dissemination of “Mars science data” collected by the mission, which will be treated separately from the technical data from the spacecraft. Red Dragon, if it were to land successfully on Mars, apparently would not operate on the surface for long: the milestones include a post-mission review 60 days after landing.

NASA Deputy Administrator Dava Newman briefly mentioned the revised agreement with SpaceX in an April 27 blog post that broadly discusses the agency’s commercial partnerships. “In exchange for Martian entry, descent, and landing data from SpaceX, NASA will offer technical support for the firm’s plan to attempt to land an uncrewed Dragon 2 spacecraft on Mars,” she wrote.

Musk, meanwhile, has been hinting for months that he will reveal more details about his long-term Mars plan at the International Astronautical Congress in Guadalajara, Mexico, in September. “I thought it would be a good venue to describe what we think would be a good approach,” he said during a press conference April 8 at NASA’s Kennedy Space Center after the Falcon 9 launch of a Dragon cargo spacecraft to the International Space Station.

That approach, he added, included eventually establishing a “city” on Mars. “I think it’s going to sound pretty crazy,” he acknowledged. “So, it should be at least entertaining.”