SpaceX's quest to help humanity colonize Mars isn't interfering with the company's contracted work closer to home, Elon Musk said.

Last night (Sept. 28), the billionaire entrepreneur presented the latest design details of Starship and Super Heavy , the reusable spacecraft and rocket that SpaceX is developing to get people to and from the moon, Mars and other cosmic destinations.

This talk has become a fall tradition; Musk has given a Starship-Super Heavy update every September since 2016. Last night's edition took place at SpaceX's South Texas facility, where the company recently finished assembling Starship Mk1 , a full-size prototype that Musk said will launch on a 12-mile-high (20 kilometers) uncrewed test mission in a month or two.

Related: SpaceX's Starship and Super Heavy Mars Rocket in Pictures

SpaceX's progress on Starship has caught the attention of many people around the world — including NASA Administrator Jim Bridenstine, who highlighted delays on one of the company's other high-profile projects.

"I am looking forward to the SpaceX announcement tomorrow," Bridenstine wrote on Twitter Friday (Sept. 27) . "In the meantime, Commercial Crew is years behind schedule. NASA expects to see the same level of enthusiasm focused on the investments of the taxpayer. It's time to deliver."

Commercial Crew is a NASA program that's encouraging the development of private American space taxis, which will take agency astronauts to and from the International Space Station (ISS). The United States has been unable to launch its own astronauts since the space shuttle was retired in July 2011; ever since, Russian Soyuz spacecraft have been the only crewed ride to and from the ISS.

The Commercial Crew program was born in 2010. In September 2014, NASA awarded multibillion-dollar Commercial Crew deals to both SpaceX and Boeing, which are building capsules called Crew Dragon and the CST-100 Starliner, respectively. The goal was to have at least one of those spacecraft up and running by the end of 2017, NASA officials said at the time.

That didn't happen, of course.

Crew Dragon seemed poised for big things not too long ago; the vehicle visited the ISS in March on a landmark uncrewed test flight. But a month later, the capsule was destroyed during a test of its SuperDraco escape engines.

Related: SpaceX's Crew Dragon Demo-1 Test Flight in Pictures

Starliner has yet to launch on its first test mission to the orbiting lab, and it's unclear when that flight will take place. In July, shortly after the reassignment of Bill Gerstenmaier, the longtime Associate Administrator for Human Exploration and Operations, NASA stopped posting targeted test-flight dates on its Commercial Crew page.

"NASA and our partners want to fly astronauts as quickly as we can without compromising the safety of our astronauts and always will give safety precedence over schedule," agency officials wrote in a July blog post . "However, our schedules matter. The NASA Administrator has directed all programs in the Human Exploration and Operations Directorate to re-examine flight dates once new leadership is in place to deliver realistic schedule plans."

That new leadership is not yet firmly in place; former NASA astronaut Ken Bowersox currently leads the Human Exploration and Operations Directorate in an acting capacity.

Musk addressed Bridenstine's tweet during the question-and-answer portion of last night's event, stressing that the Starship work is not interfering with Crew Dragon development in any meaningful way.

"To be clear, the vast majority of our resources are on Dragon and Falcon, especially Crew Dragon," Musk said. (SpaceX also launches robotic resupply missions to the ISS under a different NASA contract, using a cargo version of Dragon. Both Dragon variants launch atop SpaceX Falcon 9 rockets.)

"It was really quite a small percentage of SpaceX that’s [devoted to] Starship — less than 5% of the company, basically," he added.

Musk did not discuss the cause of the Crew Dragon schedule slips. But a former NASA No. 2 placed some blame on Congress.

"Friendly reminder that Congress cut commercial crew funding by more than 50% for the first 5 years! ($500M became $230M, $800M became $400M etc.) Meanwhile, SLS/Orion requests of $3-4B got $100M's added by Congress. Not all schedule slips should be created equal," Lori Garver, who served as NASA Deputy Administrator from 2009 to 2013, said via Twitter yesterday, in response to Bridenstine's tweet. (SLS is the Space Launch System, the huge rocket NASA is building to take its astronauts to the moon and Mars. Orion is the crew capsule that will ride atop SLS).

"Quick review of numbers @NASA requested $5.8B in '11 request for 5-yr runout & received $2.4B from Congress for those 5 yrs. NASA requested $11.2B for SLS/Orion & received $16.3B over same 5 yrs — in addition to ~$16 spent on CxP. More $ on Soyuz seats due to of these decisions," Garver added in another tweet yesterday. (CxP refers to Constellation, the moon-focused human exploration program that was cancelled in 2010.)