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Shuttle System

Photo of Ground Launch Sequencer Console

Debbie Awtonomow

Orbiter Project Engineer - Ground Launch Sequencer (GLS)
Shuttle Project Engineer

Which console do you man in the Firing Room?

The Integration console, and, if required, the Backup console. Many systems on the Shuttle are considered so critical that a backup or redundant unit is available in case the primary one fails. Although not part of the Shuttle itself, some ground support equipment (GSE) used to process the Shuttle is also considered critical. The Integration console is one of those items. If it fails during a launch countdown, we switch over to a Backup console which is already loaded with the same software.

What system(s) do you monitor and control from that console?

Like many members of the KSC launch team, I do more than one job. I work as both an Orbiter Project Engineer and a Shuttle Project Engineer. As an Orbiter Project Engineer, I operate the Ground Launch Sequencer (GLS). As a Shuttle Project Engineer, I integrate the activities that go on among all the engineers who monitor and control their systems from the Firing Room.

How are those systems used by the Space Shuttle?

The Ground Launch Sequencer (GLS) is software that runs on the Launch Processing System (LPS) to control the final portion of the launch countdown. The GLS software can react much faster than humans. If the countdown needs to be halted, GLS can stop the count all the way down to T-0 (liftoff). However, if the countdown is stopped anywhere between T-31 seconds and T-0, the launch will have to be scrubbed for at least 24 hours. If the engines have started, launch will be delayed even longer.

GLS monitors approximately 1500 measurements from T-2 hours to T-0 through safing. It also sends around 400 commands to both ground support equipment (GSE) and the Shuttle. At T-20 minutes, the GLS syncs up with the Orbiter computers. GLS controls the countdown clock and liftoff time. GLS also performs critical safing and contingency procedures if necessary (approximately 550 commands). Here are some examples of what GLS does:

What are your responsibilities with regard to those systems?

As an Orbiter Project Engineer, I operate the Ground Launch Sequencer (GLS) described above.

As a Shuttle Project Engineer, I provide leadership during daily and launch countdown activities in the Firing Room. This is especially important during troubleshooting of a problem. We coordinate the plan of action and its effect on all the systems in the firing room.

To accomplish this, we establish Launch Commit Criteria (LCC). LCC are detailed performance criteria that must be met prior to committing the Space Shuttle for launch. They ensure that all flight and ground systems are configured and performing as required to support vehicle and crew safety, mission success, and SRB recovery .

LCC apply to all operations and support elements involved in the launch countdown starting with external tank (ET) cryogenic loading at T-6 hours through Solid Rocket Booster (SRB) ignition at T-0. Violation of any LCC is considered a constraint to launch. Some examples of LCC are:

What was your most exciting or memorable experience while working in the Firing Room?

The first shuttle mission, STS1, was by far my most memorable experience in the firing room. The first launch attempt was scrubbed because of a timing problem between the four primary computers and the backup computer onboard the Shuttle; but the second attempt was successful. Watching the main engines and Solid Rocket Boosters (SRBs) light up, feeling the rumble in the firing room, and the Shuttle clearing the tower, pitching over and climbing into the blue sky was heart stopping.

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Page Last Revised: 03-May-2004
Curator: Berta Alfonso Berta.A.Alfonso@nasa.gov / NASA, XA-D1
A Service of the NASA/KSC External Relations and Business Development Directorate, Lisa A. Malone, Director