Boeing is fighting back against a recent report on NASA's Commercial Crew Program from the agency's Office of Inspector General (OIG).

NASA has been encouraging the development of private astronaut taxis for nearly a decade via Commercial Crew, aiming to end the United States' dependence on Russian Soyuz vehicles for crewed missions to and from the International Space Station (ISS). That dependence has been total since NASA grounded its space shuttle fleet in July 2011.

Boeing and SpaceX emerged as the big Commercial Crew winners in September 2014, scoring contracts currently worth $4.3 billion and $2.5 billion, respectively, to get vehicles up and running and to fly six missions apiece to and from the ISS. Both companies are developing capsules; Boeing's is called the CST-100 Starliner , and SpaceX's is Crew Dragon .

Related: Crew Dragon & Starliner: A Look at the Upcoming Astronaut Taxis

Back in 2014, NASA officials said they hoped that at least one of the capsules would be operational by 2017. That didn't happen, of course. The 53-page OIG report , which was released last week, looked into schedule delays and other issues, serving as a broad audit of the Commercial Crew Program.

The report estimated that NASA will end up paying about $90 million per seat to fly astronauts to and from the ISS aboard Starliner, compared to just $55 million per seat on Crew Dragon. (For reference, a seat on the three-person Soyuz currently costs NASA about $85 million.)

Boeing said that $90 million figure is too high, and the company took issue with some of the report's other findings as well.

"We strongly disagree with the report's conclusions about CST-100 Starliner pricing and readiness, and we owe it to the space community and the American public to share the facts the inspector general missed," Jim Chilton, vice president and general manager of Boeing Space and Launch, said in a statement .

"Each member of the Boeing team has a personal stake in the safety, quality and integrity of what we offer our customers, and since Day 1, the Starliner team has approached this program with a commitment to design, develop and launch a vehicle that we and NASA can be proud of," he added.

Chilton's words are part of a nearly 1,100-word statement that Boeing released yesterday (Nov. 18). In the statement, company representatives argued that Starliner's per-seat price is actually lower than the OIG's estimate, because NASA will fly lots of cargo aboard the capsule as well. (Both Starliner and Crew Dragon can accommodate seven astronauts but are expected to fly just four people on each contracted Commercial Crew mission.)

The Boeing statement also defended the company's larger Commercial Crew contract. The higher award makes sense, Boeing wrote, given that Starliner was developed "from scratch" whereas SpaceX leveraged tech from the company's robotic Dragon cargo capsule, which has been flying ISS resupply missions since 2012 under a different NASA contract.

These arguments echo points that Boeing spokespeople made to Space.com and other outlets late last week, when the first round of stories about the OIG report went up. But Chilton's strong words are new, as is the posting of a detailed response on the company's website.

Both Starliner and Crew Dragon are in the home stretch of development. SpaceX's capsule has already flown to the ISS once, on the weeklong, uncrewed Demo-1 mission this past March. The company is currently gearing up for a crucial "in-flight abort" (IFA) test, which will prove out Crew Dragon's ability to get astronauts away from danger in the event of a launch emergency. If everything goes well with the IFA, SpaceX will be clear to launch a crewed demonstration flight to the orbiting lab early next year, with contracted missions starting sometime thereafter.

Boeing, meanwhile, plans to launch its uncrewed ISS demonstration flight on Dec. 17. If that mission goes according to plan, "we are well positioned to fly our first crew in early 2020," company representatives said in yesterday's statement.

Mike Wall's book about the search for alien life, " Out There " (Grand Central Publishing, 2018; illustrated by Karl Tate ), is out now. Follow him on Twitter @michaeldwall . Follow us on Twitter @Spacedotcom or Facebook .