* Rocket exploded Thursday, tightening U.S. launch

bottleneck

* Blue Origin has not yet determined cause of the blast

* Launching pad support tower needs repair, fuel tanks

okay

(New throughout, adds details and background)

By Joey Roulette

June 2 (Reuters) - Blue Origin will return its New Glenn

rocket to flight before the year ends, CEO Dave Limp said late

on Monday, days after one of the rockets exploded, damaging the

company's launch pad and tightening a U.S. launch bottleneck for

satellite companies.

Blue Origin staff has inspected damage to the company's only

launch pad, and the company has not said what may have caused

the explosion on Thursday.

Limp said key fuel tanks at the pad "are all in good shape,"

calling it "good luck" because replacing those assets if damaged

would take a long time. Nearby rocket boosters on deck for

future flights "also look good," he said, but the pad's main

support tower needs repair.

The New Glenn explosion, though no satellites were onboard

and no one was injured, was one of Blue Origin's most dire

failures since its founding in 2000, besetting both its

centerpiece rocket and the sole launch pad it blasts off from.

A grounding that could last until year end follows a mission

failure in April on New Glenn's third flight. Blue Origin has

been under pressure to increase New Glenn's flight rate due to

mounting competition from Elon Musk's SpaceX, the world's most

active launch company.

The New Glenn explosion thundered across the Space Coast of

Cape Canaveral, Florida as the company, owned by billionaire

Jeff Bezos, was preparing to launch 48 internet satellites for

Amazon, Blue Origin's biggest private customer.

Amazon similarly faces competitive pressure to expand its

satellite constellation to compete with Musk's Starlink.

Amazon also has launch arrangements with United Launch

Alliance, the joint rocket venture of Boeing-Lockheed Martin,

and French launcher Arianespace. A ULA Atlas V rocket put 29

Amazon Leo satellites into orbit on Friday.

Limp did not speculate on the possible cause of the New

Glenn explosion, which occurred as the company attempted a

hot-fire test, test-firing the rocket's engines while fixed to

the ground in routine mission preparations.

SpaceX suffered a similar launch pad explosion with its

Falcon 9 rocket in 2016 as it was loading fuel for a hot-fire

test, and more broadly as the company was trying to increase the

rocket's flight rate. SpaceX returned Falcon 9 to flight roughly

four months after the explosion.

Blue Origin suffered a failure in 2022 during an uncrewed

flight of its now-shelved New Shepard suborbital rocket. After a

structural failure of the rocket's engine nozzle mid-flight, the

rocket did not return to flight until a year and three months

later, following Blue Origin's technical investigation and a

review by the U.S. Federal Aviation Administration.

In January, Limp paused the New Shepard program and shifted

its staff and resources to New Glenn and the company's moon

lander work for NASA, two programs with tight timelines. Blue

Origin had planned to launch an early version of its Blue Moon

lander on New Glenn this year.