An ongoing problem with fuel sensors has forced NASA to postpone the latest mission of the space shuttle to the International Space Station (ISS). Yesterday, the malfunction of two gauges that measure liquid hydrogen in the external fuel tank of the shuttle prompted managers in the space agency to halt an already postponed launch attempt and reschedule it for 2 January at the earliest. The problem is in the four engine cut-off (ECO) sensors, which have variously given off false readings during fueling procedures in preparation for the latest mission of the Atlantis orbiter, designated STS-122.
The faulty ECO gauges have been a source of trouble for the shuttle launch team at Cape Canaveral for quite a while. In the past, NASA has tried to work around them, launching orbiters into space even when one or two of them have acted strangely. Not this time, though. The space agency said on its shuttle Web site that this time it had had enough and was temporarily shutting down the current mission until engineers could inspect and fix the mysterious problem once and for all.
The ECO system is designed to warn flight controllers that fuel is running unexpectedly low and trigger an automatic cut off of the main engines, preventing any damage on ascent.
"We're determined to get to the bottom of this," said LeRoy Cain, chairman of the mission management team. He added that launching on the rescheduled date would depend on the work of the engineers to fix the ECO problem.
"We would rather have launched today, obviously," Cain said Sunday. "This was going to be, in the very least, a good tanking test for us, and that's what it's turned out to be."
The crew of STS-122 flew back to Houston on Sunday, but they expressed their gratitude to the launch crew for their efforts before leaving, according to the space agency.
"We want to thank everyone who worked so hard to get us into space this launch window," the astronauts said in a statement. "We had support teams working around the clock at KSC, JSC, and numerous sites in Europe. We were ready to fly but understand that these types of technical challenges are part of the space program. We hope everyone gets some well-deserved rest, and we will be back to try again when the vehicle is ready to fly."
The main objective of the 11-day mission of Atlantis will be to install and activate the European Space Agency's Columbus laboratory, which will provide scientists around the world with the ability to conduct a variety of life, physical, and materials science experiments in weightlessness.
First, though, they need to shake a few bugs out.