CAPE CANAVERAL, Fla. (AP) — NASA was aiming for a Saturday launch of its new moon rocket, after fixing fuel leaks and working around a bad engine sensor that thwarted the first attempt.
The maiden flight of the 322-foot (98-meter) rocket, the most powerful ever built by NASA, was delayed Monday at the end of the countdown. Clocks at the Kennedy Space Center started ticking again as managers expressed confidence in their plan and forecasters gave favorable weather odds.
Atop the rocket is a crew capsule with three test dummies that will fly around the moon and back over the course of six weeks — NASA’s first attempt since the Apollo program 50 years ago. NASA wants to wipe out the spacecraft before placing astronauts on its next scheduled flight in two years.
NASA Administrator Bill Nelson said he has more confidence in this second launch attempt, given everything engineers learned from the first attempt.
So is astronaut Jessica Meir, who is on NASA’s short list for one of the initial moon crews.
“We’re all excited for this to come out, but the most important thing is that we go when we’re ready and do it right, because the next missions will have humans on board. Maybe me, maybe my friends,” Meir told The Associated Press on Friday.
Engineers responsible for the Space Launch System rocket insisted Thursday evening that the rocket’s four main engines were fine and that a faulty temperature sensor made one of them appear to be overheating on Monday. The engines must match the minus -420 degrees Fahrenheit (minus-250 degrees Celsius) of the liquid hydrogen fuel at takeoff, otherwise they could be damaged and shut down in flight.
“We’re convinced beyond a shadow of a doubt that we have good quality liquid hydrogen going through the engines,” said John Honeycutt, the rocket’s program manager.
Once fueling begins Saturday morning, the launch team will conduct another engine test, this time before the countdown. Even if that suspect sensor indicates an engine is overheating, other sensors can be relied on to make sure everything is working properly and stop the countdown if there’s a problem, Honeycutt told reporters.
NASA was unable to perform this type of engine test during general tests earlier this year due to fuel leaks. More fuel leaks emerged on Monday; technicians found some loose connections and tightened them.
The engine temperature situation adds to the flight’s risk, as does another problem that emerged Monday: cracks in the rocket’s foam insulation. If a piece of foam breaks off on takeoff, it could hit the belt drives and damage them. Engineers consider the likelihood of this happening to be low and have accepted these slight additional risks.
“This is an extremely complicated machine and system. Millions of parts,” NASA chief Nelson told the AP. “In fact, there are risks. But are these risks acceptable? I leave that to the experts. My role is to remind them that you are not taking any risk that is not an acceptable risk.”
The $4.1 billion test flight is NASA’s first step toward sending astronauts around the moon in 2024 and landing them on the surface in 2025. Astronauts last walked on the moon in 1972.