The cost of returning astronauts to the Moon is soaring, despite the fact that NASA's plans are on their way.

Over the last eleven years, the agency's development of its Space Launch System has been plagued with budget overruns and many years of delays.

NASA has yet to launch the SLS or complete a full range of tests. During wet dress rehearsals in April, the agency's Artemis I rocket, meant to launch the first uncrewed mission around the moon later this year, encountered valve issues so serious that they forced NASA to push the tests back to this month

The bills are getting bigger. NASA spent a lot of money on a mobile launch tower that was supposed to be used to launch the SLS rocket and its companion craft.

The space agency's costly efforts could be dealt a stinging rebuke by an oversight report.

NASA expects the Inspector General's report on spiraling costs for its second mobile launch tower to come out this week. It's a really big deal.

Ground crews can fuel and communicate with the rocket with the help of the tower. The tower is designed to release each of its "umbilicals" so that the rocket can launch safely from the Kennedy's Space Center.

The agency's plans may be thrown into disarray by the sticker shock. Some lawmakers don't like the SLS project.

NASA Watch said this was "utterly indefensible and is totally on NASA regardless of how contractors messed up."

According to NASA Inspector General Paul Martin, each SLS launch could cost as much as $4.1 billion, more than twice the already-ludicrous $2 billion target, which he said at the time was "a price tag that strikes us as unsustainable."

NASA may not be solely responsible for rising costs. The agency was forced to pay extra compensation to its contractors in order to cover their costs, known as "cost-plus" rules set out by Congress, according to Martin.

NASA's contract to deliver astronauts to the surface of the moon is one of the threats to the SLS program.

Musk's company has made great strides in constructing its own launch tower, setting the stage for the long-awaited maiden voyage of its spaceship into space later this summer.

SLS could be obsolete soon after it's debut if it succeeds on a reasonable schedule.

All that is happening now. In less than two weeks, NASA will attempt a fourth attempt at rolling out its massive SLS rocket to the launch pad at Launch Complex 39B.

It's not clear whether the tests will distract from the huge costs involved.

Journalists slam NASA for lack of transparency surrounding moon rocket launch.