The Twitter account "Everything Artemis" asked Musk whether he expected to have Starship ready to land humans on the moon by 2024.
"Probably sooner," Musk replied just two minutes later.
Earlier Saturday, CNBC space reporter Michael Sheetz pointed out that NASA had paid $300 million to SpaceX on July 30 toward Starship, representing the agency’s most recent major allocation toward the project.
Sheetz’s post included a link to the federal USASpending.gov website, which documents government spending.
The site claimed that $439.6 million has so far been paid to SpaceX for what’s considered to be a $3 billion project.
Just three days earlier, Musk went on Twitter to defend the Starship project amid complaints from Amazon boss Jeff Bezos’ Blue Origin space organization that NASA has decided to award just one moon-lander contract for its Human Landing System (HLS) program.
Blue Origin has asserted that SpaceX received preferential treatment in receiving the NASA contract.
"We are especially concerned with the lack of flight readiness reviews in SpaceX's proposal," Blue Origin had written in a statement to Fox Business. "SpaceX's complex approach requires 16 consecutive launches with only three total flight readiness reviews instead of one for each launch which is consistent with common industry practice. Flight readiness reviews are fundamental to safety and are especially important with reusable vehicles and multiple launches in rapid succession."
Musk responded to Blue Origin's statement a tweet, clarifying that 16 Starship flights is "extremely unlikely."
"Starship payload to orbit is ~150 tons , so max of 8 to fill 1200 ton tanks of lunar Starship," Musk said. "Without flaps & heat shield, Starship is much lighter. Lunar landing legs don’t add much (1/6 gravity). May only need 1/2 full, ie 4 tanker flights."
However, he noted that it would not be a problem even if 16 flights were required.
"SpaceX did more than 16 orbital flights in first half of 2021 & has docked with Station (much harder than docking with our own ship) over 20 times," Musk added.
Fox Business’ Lucas Manfredi contributed to this story.