Table of Contents

Mission Overview - CAPCOMS

The critical role of a CAPCOM

Amidst the hundreds of people involved in coordinating every aspect of a shuttle and its crew, not everyone can speak to the on-orbit astronauts. Such commotion would lead to confusion and costly, even fatal, errors. CAPCOMS, a name derived from the CAPsule COMmunicators from NASA's earliest missions in space, when spacecraft were known as capsules, act as the orbiting astronauts' sole voice from Mission Control.

Today there are two Mission Control Centers, one dedicated to the Shuttle Program and the other designated to support activities onboard the International Space Station. Together, they ensure a coordinated, consistent, and efficient line of communication. A Shuttle CAPCOM is on duty for the duration of the shuttle mission, whereas Station CAPCOMS, as a group, are on duty 7 days a week, since the Station is now permanently inhabited. In general, the Shuttle CAPCOM speaks to astronauts during the mission regarding activities that take place onboard the shuttle. The Station CAPCOM speaks with the crew regarding Station activities.

The ground-to-space voice communication link being a limited and precious resource, CAPCOMS must first and foremost be excellent communicators. Voice communications must be concise and clear while at the same time provide all the necessary information that the onboard crew needs to correctly perform their duties and understand the overall situation. CAPCOMS have a broad understanding of all Station and shuttle systems that allow them to participate in discussions held in Mission Control and troubleshooting planning. As a rule, flown astronauts work as CAPCOMS since they have an understanding of what the flight crew is going through at any given time. Their training and experience gives them the ability to ensure that directions given to the on-orbit crew are practical and consider human factors. This type of operational experience is also referred to as "situational awareness." During a flight the CAPCOMS must use their best judgement to decide how and when information should be passed along to the crew.

During Mission STS-111, Canadian Space Agency astronauts Dr. Steve MacLean and
Dr. Robert Thirsk will be the two direct voice links between the Mission Control Centers at the Johnson Space Center in Houston, and their colleagues in orbit. Trained and experienced space travelers themselves, they will give sound advice and follow mission activities from separate rooms. Dr. MacLean will be in direct contact with the Endeavour shuttle crew while Dr. Thirsk will provide support to the crew onboard the Station.

CAPCOMS report directly to the Flight Directors (of the shuttle or the Station) who are responsible for all operations and make decisions regarding safety and overall successful flight conduct.