Washington, Feb 22 (IANS): After replacing faulty control mechanisms, all core stage rocket engines on NASA's moon rocket have performed successfully in a recent series of tests, the US space agency said.

Last month, a faulty controller on the RS-25 engine number 4 forced NASA to delay its upcoming Artemis I uncrewed moon mission.

The mission aims to mark the beginning of humanity's return to the moon.

"All four engine controllers performed as expected during power up, as part of the Artemis I Core Stage engineering tests," NASA said in a statement.

The RS-25 engines are manufactured by US-based Aerojet Rocketdyne.

There are four RS-25 engines powering the core stage of the Space Launch System (SLS) moon rocket.

TheA company conducted numerous tests on the faulty engine four controller and determined the cause to be a faulty memory chip.

The device is used only during the controller start-up sequence and has no impact on controller operations beyond that point. Further, the mission engineers found no indication of faulty memory chips on the other three engines, and therefore there is no related constraints to the wet dress rehearsal or launch, NASA said.

The fault, however, forced NASA to postpone the Artemis I launch to no earlier than April.

Meanwhile, teams at Kennedy Space Center in Florida, are completing remaining SLS pre-flight diagnostic tests and hardware closeouts, including testing the flight termination system and installing instrumentation on the twin solid rocket boosters.

After that the rocket and spacecraft will be rolled to Launch Pad 39B for the first time in March for a final wet dress test before launch, NASA said.

During this test, the launch team will fuel the rocket and run through the pre-launch sequence all the way to the countdown.

Following the success of the test, NASA said it will fix a date for the mission launch.