NASA is still having trouble managing the development of its next big rocket, the Space Launch System, a new audit has found. The report is the latest in a string of damning reports from NASA’s inspector general, which has been warning about scheduling and budget problems with the rocket for years.

The Space Launch System, or SLS, is the epicenter of NASA’s Artemis program, the agency’s plan to return humans to the Moon by 2024 and put the first woman on the lunar surface. Once complete, the SLS is set to be the most powerful rocket in the world, capable of lofting more than 200,000 pounds of material into low Earth orbit. NASA plans to fly people on top of the SLS, sending them to dock with a small station around the Moon where they will then journey down to the surface in a lander.

Since the SLS is so crucial to NASA’s lunar ambitions, the inspector general did a complete assessment of the contracts for all of the major elements of the rocket. Three government contractors — Boeing, Aerojet Rocketdyne, and Northrop Grumman — are working on the rocket; Boeing is handling the majority of the vehicle, while Aerojet makes the engines and Northrop is making boosters that will give the rocket extra thrust at liftoff. All of the contractors have experienced technical problems and setbacks, resulting in $2 billion of cost increases and two years of delays, the report said. In fact, the entire SLS program is over budget and behind schedule by more than 33 percent, compared to the baseline figures NASA gave Congress for 2019. And that will probably grow to 43 percent, the report says, as more schedule delays occur.

All of the contractors have experienced technical problems and setbacks

NASA originally hoped the rocket would make its debut in 2017. But Boeing only finished building the core of the rocket earlier this year before shipping it to Mississippi for testing. For a while, NASA has been targeting the SLS to launch on its first uncrewed test flight in November of this year, but officials at the agency have conceded that SLS won’t fly until 2021 at the earliest.

In the meantime, the cost of the program has ballooned. Until December 2019, the SLS program had cost a total of $14.8 billion, and it’s expected to grow to $17 billion by the end of this year, according to the inspector general. Of that total, $6 billion isn’t being reported or tracked. Regardless, the total cost is 60 percent more than the $10.8 billion that NASA had originally envisioned for the project back in 2014, the audit said. The program will likely grow to $18.3 billion by the time the rocket actually flies next year — if the vehicle can make the new 2021 deadline. If the second flight of the SLS slips to 2023, the entire program will probably be $22.8 billion by then, according to the audit.

The inspector general chalks these problems up to technical issues, bad management, and poor performances from the NASA contractors. NASA’s scope for the SLS has constantly been in flux, with the agency changing the design of the vehicle for various upcoming missions. Additionally, the inspector general admonishes NASA for continuing to hand over award fees to Boeing and other contractors, despite missing deadlines and bad performance. Boeing and NASA have blamed their poor performance on the fact that it’s been 50 years since anyone has developed a rocket of this size, and that expertise has thinned since then.

NASA’s inspector general, along with the Government Accountability Office, has been warning about the mismanagement of the SLS program for years. Audit after audit has questioned NASA’s timetable for the rocket and pointed out flaws in the way Boeing has managed the program. This particular report also comes at a vulnerable time for Boeing, just a few months after the company’s other spacecraft in development, the CST-100 Starliner, made a less-than-stellar debut flight for NASA. A recent investigation into the Starliner’s botched mission revealed 61 corrective actions that Boeing needs to take to fix the problems experienced during the flight.

“NASA has already begun implementing improvements.”

As for the SLS, the inspector general has some suggestions about how to address those issues. The audit says that NASA needs to let Congress know that the program has exceeded its timeline and budget, take a closer look at how people are managing these programs, and develop a new cost accounting model.

In response to the audit, NASA agreed to make all of the changes the inspector general suggested, and it plans to create a new timetable for the program moving forward. “NASA has already begun implementing improvements to better track cost and schedule and to report progress against baseline,” NASA officials said in response.

Boeing also argued that it has learned a lot while developing the SLS. “The hard-earned experience acquired during initial SLS development is resulting in significant savings and efficiencies in subsequent development and production,” Boeing said to The Verge in a statement. “We’re committed to supporting NASA’s vision to having boots on the moon by 2024.”

Seeing as how the SLS program has continually struggled with timelines, it’s unclear if the rocket will actually meet its deadline next year. And with all of these delays, it becomes increasingly unlikely that NASA will be able to meet its goal of sending humans back to the Moon by 2024, especially if the SLS is a central part of that plan. No matter what, the SLS program promises to be a very expensive endeavor for NASA. The inspector general estimated that the entire SLS program, along with the Orion crew capsule needed to carry humans and the ground systems needed to support the rocket, will have cost NASA $50 billion by 2024.

Updated March 10th, 3:30PM ET: This article was updated to include a statement from Boeing.