April 2, 2003
A: FROM MENTOR ANDREA GATICA IN TX
The Space Shuttle normally flies approximately six times
each year. The total number of people working on the Shuttle program is
probably in the neighborhood of 15,000. However, the number of people
working on a specific mission when it is flying is small compared to the
total work force.

The United Space Alliance (USA) is the prime contractor for
Shuttle Operations and employs approximately 10,000 personnel. Several
hundred USA employees support the International Space Station but most
support the Space Shuttle program. NASA has several thousand employees
supporting the Shuttle Program plus other contractors responsible for
supplying equipment for Shuttle support employ several thousand additional
personnel.

This large work force is necessary because of the complexity
of the Space Shuttle Program and the criticality of the equipment. For
example each time a Shuttle launches an external tank (the large orange tank
that the Shuttle is attached to) is used and discarded after the Shuttle is
in Space. Therefore, a new external tank must be built for each Shuttle
launch. In addition, the Solid Rocket motors used for each launch are
recovered from the ocean and must be refurbished for reuse. The Shuttle
vehicle itself must undergo extensive testing and some refurbishment between
flights.

As one can see the time a Shuttle is in orbit is a very
small part of the time that the Shuttle is being worked on. Thus, the
majority of personnel working on the Shuttle are associated with preparing
the Shuttle vehicle and it's component for launch. When the Shuttle is in
orbit the primary support is provided from the Mission Control Center in
Houston, Texas. These personnel are called the Mission Operations Team and
consist of approximately 50 people per shift. Since there are three shifts
per day, that ads up to approximately 150 people supporting Shuttle
Operations around the clock when the Shuttle is in orbit. After the Shuttle
lands these people begin planning for future fights including training in
simulators.
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February 21, 2003
A: FROM MENTOR BARB KONTOGIANNIS IN CO
I don't have an exact number to quote, but that is probably not
unreasonable for a space launch - if you look at the whole chain of events.
I work with expendable launch vehicles, so I'll use that as an example.
Here's what goes into launching a rocket that is already designed:

1) Buying and building the hardware (individual pieces) involves more than
one hundred suppliers, at say 100 people each. Some companies have more
people working on space vehicle parts, like the ones that build the engines
or the main guidance and navigation computers, and some have fewer. Let's
estimate 10,000 people.
2) Then the rocket has to be assembled and tested. It takes roughly 2000
people to do that.
3) Launch site preparations and actually launching a rocket takes on the
order of 1000 people.
4) There are also people involved around the world in tracking the vehicle,
and the FAA and Air Force is often involved from a safety standpoint, so add
another couple hundred.
5) And we can't forget the few thousand people that designed and built the
payload (spacecraft) or instruments/experiments being delivered to space.

Altogether, this rough estimate is in the ballpark of the 15,000 people
number you have heard. If you also consider the initial concept and design
work, the number of people involved continues to grow. Space launch is an
exciting and interesting field, and it does take a lot of people to make
everything come together for a successful mission.