NASA said Thursday that it would not grant permission to fly SpaceX's Super Heavy-Starship rocket until it assesses the threat to a pad near the space station used to launch astronauts. SpaceX is building a towering new gantry at Kennedy Space Center's Complex 39A to launch its rocket.

In a few hundred feet, SpaceX will be constructing a new launch stand and gantry near NASA's original 39A firing stand, which launches Falcon 9 rockets carrying astronauts and cargo to the International Space Station.

SpaceX managers are concerned about the possibility of a catastrophic failure on or above the new Starship pad that could severely damage the Falcon 9 launch infrastructure, disrupting SpaceX astronaut flights aboard Crew Dragon capsules to the space station.

'As we experienced on one of SpaceX's early launches, an early failure would have been pretty devastating to 39A,' Kathy Lueders, NASA's chief of space operations, told Reuters. In 2016, an explosion on a launch pad at Cape Canaveral Space Force Station severely damaged launch pad 40 when it destroyed a Falcon 9 and its communications satellite payload.

With the Super Heavy-Starship, the threat is raised to a whole new level. Featuring 33 methane-burning Raptor engines, the fully reusable rocket will generate 16 million pounds of thrust at liftoff, twice as much as NASA's Space Launch System moon rocket. The rocket will weigh about 11 million pounds.

An upper stage for NASA's Artemis program will use Raptors to power a 160-foot-high Stage 1, which is expected to carry astronauts, cargo, or both. Stage 1 is being developed under a $2.9 billion NASA contract for use as the first moon lander.

Launch complex 40 was repaired and upgraded following the 2016 mishap, and a third Falcon 9 pad is now in operation at Vandenberg Aerospace Center in California. However, neither of these facilities can launch Crew Dragon astronaut shuttles.

A crew-ready pad at Cape Canaveral Space Force Station will launch Boeing's Starliner capsule, which hasn't yet been certified for operational use. NASA considers complex 39A an essential part of the ongoing operation of the space station.

In response to a CBS News query, NASA confirmed the Reuters report, saying the 39A launch complex has not yet been granted permission for SpaceX to launch. 'A thorough review will be conducted by NASA and SpaceX in the coming weeks to ensure safe operations at the pad and to assess redundant launch capabilities,' NASA said in a statement.

'SpaceX and NASA are considering all options in the review, including developing crew transportation capabilities at Space Launch Complex 40 at Cape Canaveral Space Station in Florida.'

The Pad 40 has no gantry at present, so SpaceX would need to customize and upgrade the pad to provide access to the Crew Dragon, which is atop a Falcon 9, as well as to provide emergency escape capabilities.

In regards to SpaceX's Super Heavy-Starship, the company has already built a pad near Boca Chica, Texas, where the company will conduct orbital flight tests soon. A large crane is stacking massive open-lattice segments one atop another to create a second Starship pad at 39A.

Two gantry segments were attached early Thursday after the first was hauled out to the complex last week. NASA stated in its statement that it was responsible for assuring SpaceX complied with the requirements of the property agreement.

It described construction and safety requirements, as well as environmental conditions. 'At this time, NASA has only approved the building process. Additional review for hazards, operational impacts, and supportability will be required before launch.'