Elon Musk, founder and CEO of SpaceX, participates in a press conference at the Kennedy Space Center on May 27, 2020 in Cape Canaveral, Florida. NASA astronauts Bob Behnken and Doug Hurley were scheduled to be the first people since the end of the Space Shuttle program in 2011 to be launched into space from the United States, but the launch was postponed due to bad weather.Saul Martinez | Getty ImagesSpaceX launched astronauts for the first time barely a week ago but CEO Elon Musk does not want the company resting on its laurels.Instead, Musk urged SpaceX employees to accelerate progress on its next-generation Starship rocket “dramatically and immediately,” writing Saturday in a company-wide email seen by CNBC.”Please consider the top SpaceX priority (apart from anything that could reduce Dragon return risk) to be Starship,” Musk wrote in the email.SpaceX did not immediately respond to CNBC’s request for comment on Musk’s email.His space company launched a pair of NASA astronauts on May 30, marking a historic first for SpaceX and a crucial step forward for the U.S. space program. A SpaceX Falcon 9 rocket and Crew Dragon capsule carried the astronauts to orbit and on to the International Space Station. That mission is ongoing, as Musk noted, with the spacecraft set to return the astronauts to Earth in the next couple months.A SpaceX Falcon 9 rocket carrying the company’s Crew Dragon spacecraft is launched on the Demo-2 mission with NASA astronauts Robert Behnken and Douglas Hurley onboard.NASA/Bill IngallsThe Falcon 9 rocket that launched the astronauts is the mainstay of SpaceX’s business, with 85 missions over the past decade. But Starship represents the company’s aim to make obsolete even the cost-saving advances of its Falcon 9 fleet. Its Falcon 9 rockets are partially reusable, as the company often lands the large “booster” stage of the rocket and recovers the rocket’s nosecone. But Musk’s goal is to make Starship fully reusable — envisioning a rocket that is more akin to a commercial airplane, with short turnaround times between flights.Musk last year unveiled the Starship prototype, built of stainless steel and dwarfing the company’s existing spacecraft. SpaceX is developing Starship with the goal of launching as many as 100 people at a time on missions to the moon and Mars.SpaceX’s first Starship prototype under construction near Boca Chica, Texas in 2019.SpaceX”We need to accelerate Starship progress,” Musk said in Saturday’s email.Musk’s emphasis on Starship comes nine months after a controversial comment by NASA Administrator Jim Bridenstine, just before SpaceX unveiled the latest prototype. The NASA chief declared his agency wanted “to see the same level of enthusiasm” for SpaceX launching NASA astronauts as there was for the Starship program, saying it was “time to deliver.” At the time, Musk said that SpaceX “resources are overwhelmingly” focused on finishing development of the Crew Dragon spacecraft. Now, with SpaceX having delivered on the first part of its commitment to fly NASA astronauts, Musk is turning the company’s attention to Starship.SpaceX has raised nearly $1.7 billion since the beginning of 2019, with its valuation rising to around $36 billion according to CNBC sources. The company has steadily raised funding as its developed three ambitious programs: the Crew Dragon spacecraft, its Starlink internet satellites and the massive Starship rocket.The Starship program has seen prototypes pass several critical milestones but SpaceX has yet to begin flight testing its most recent design. A previous iteration, known as Starhopper, completed a short launch and landing flight test in August.Airlift to TexasSpaceX continues to build up its facility in Boca Chica, an area along the Gulf of Mexico at the most southern part of the U.S. and Mexico border in Texas. Musk noted that he’s often been on site at Boca Chica recently and continues to do so. On Saturday he tweeted an aerial view of the complex, showing its growing array of production tents and rocket manufacturing bays.In his email, Musk asked SpaceX employees to “consider spending significant time” in Boca Chica to help further accelerate Starship development. SpaceX has about 8,000 employees, most of whom are at the company’s Los Angeles area headquarters or its facilities at Cape Canaveral, Florida or near Austin, Texas. Although SpaceX has some land under lease in the Port of Los Angeles for Starship development, Musk’s email implied that the company is seeking to incentivize employees to move to Texas from California and Florida.”For those considering moving, we will always offer a dedicated SpaceX aircraft to shuttle people,” Musk wrote.SpaceX owns and operates at least one private jet, as the company has charged Tesla for use of the aircraft as recently as the first quarter of 2020. But the extraordinary relocation offer underlines how crucial Musk sees the Starship project. The company’s Boca Chica team is already working nearly around the clock but Musk wants more, urging SpaceX employees to help Starship development progress even more quickly.Subscribe to CNBC PRO for exclusive insights and analysis, and live business day programming from around the world.