As the countdown clock clicked down toward the launch of space shuttle Discovery on mission STS-120, the team in the Launch Control Center at NASA’s Kennedy Space Center had to make the “go/no-go” decision for launch. Before making the call, they needed to carefully examine a small ice build-up on the external tank’s liquid hydrogen umbilical, reported by the Final Inspection Team, to ensure the ice posed no threat upon liftoff.
For the first time, launch managers had a new capability at their fingertips: instant access to the inspection team’s digital images transmitted to them directly from the launch pad via fiber-optic cable.
It’s not that sending images from a laptop computer is a revolutionary idea. It had been considered before, but wireless transmission wasn’t possible with a fully fueled space shuttle just feet away.
The photo transmission capability is a built-in requirement for NASA’s next generation of spacecraft under the Constellation Program, so the inspection team members were already looking for ways to safely transmit pictures from the launch pad. Their plans got a jump-start when shuttle managers were concerned that a newly shortened hold in the countdown also would reduce the time they had to analyze the photos that the team delivered by hand from the pad.
“We looked into sending images back wirelessly, but our safety requirements wouldn’t allow that,” explained Tom Ford, who heads the inspection team. “So we said OK, we have to have this. Let’s think of a barebones system that will work while meeting the safety requirements, and we came up with the (fiber-optic) drop.”
The solution came together in the brief time between the STS-118 mission in August and the October launch of STS-120. Within about a two-week period, fiber-optic cable was installed from Launch Pad 39A’s 195-foot level down to the base. The setup provided two connection points from which the photos could be transmitted, one each at the 195 and 95-foot levels. Existing “Toughbook” laptops already used by the team were called into service and, as launch day for mission STS-120 dawned, the team was ready.
The timing was excellent. The group, also called the “Ice Team,” traveled to the pad to do its customary top-to-bottom detailed inspection of the vehicle and launch pad. The team members used the new capability to send back the photos, including some showing the ice buildup on the umbilical. In a rare move, the launch managers asked the inspection team to go back for a second look and once again send back updated photos of the now dissipating ice.
With the analysis done, the launch team made the call: Discovery was “go” for launch, and the shuttle and crew embarked on a dramatic and highly successful 15-day mission to the International Space Station.
From the inspection team’s standpoint, Ford said the analysis “was a 100-percent success” and will continue to be a vital part of the inspection process for the remainder of the shuttle program.
The importance of this new capability was echoed from the launch team.
“This new capability represented a tremendous improvement in our ability to analyze ice buildup in near-real time,” said NASA Test Director Steve Payne after the mission. “Taken together with the Final Inspection Team’s visual inspection and recommendation, it allowed us to reach a quick decision on acceptability of the ice we saw. It was perhaps the one thing that made the difference between launching or remaining on the ground that day.”
