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or eight days prior to a shuttle launch date, depending on the
TAL site, a team of NASA and contractor personnel will depart KSC
and activate the TAL sites assigned to support the mission.
Four to five days are required onsite to prepare the TAL site
for launch support. The mission support team is managed by the
NASA Ground Operations Manager (GOM) and includes about 20 contractor
personnel. Department of Defense support for NASA and the GOM
include a Deployed Forces Coordinator and two aircraft with an additional 35 personnel. The majority
of the DOD personnel arrive on site 48 hours prior to scheduled liftoff.
If a TAL were declared, the GOM
at the TAL site will be notified by Landing Support Officer
(LSO) in Mission Control Center (MCC) at the Johnson Space Center
that the Shuttle was aborting to the emergency landing site.
The LSO would begin coordination to clear the upper air space
with the Federal Aviation Administration (FAA) and the International
Civil Aviation Organization (ICAO). The U.S. State Department
will notify the American embassy country involved.
The time from declaration of a
TAL abort to a landing is estimated at about 25-30 minutes.
Once the Shuttle crew commander selects the TAL option the pre-programmed
onboard orbiter computers would automatically steer the craft
toward the designated landing site. The orbiter would roll heads-up
before main engine cutoff and all extra fuel will be dumped
to increase vehicle performance by decreasing its weight and
reducing the toxic environment in and around the orbiter after
a landing.
The shuttle would be flown at an
altitude of about 350,000 feet and the main engines would cut
off at the correct velocity. The external tank would be jettisoned
after Main Engine Cutoff (MECO), as in a normal launch, and
then tumbled to insure that it burns up on re-entry into the
Earth's atmosphere.
A preloaded re-entry program would
then go into effect, with the orbiter encountering the atmosphere
and a normal re-entry planned. Ten minutes before landing, communications
would resume through the Tracking and Data Relay Satellite (TDRS)
network, used for orbiter/Mission Control contact
The LSO and Flight Director in
the MCC would keep the GOM and the TAL site informed of the
status of the orbiter systems during the approach to the TAL
site. Data received from the TAL-site would be used to update
the orbiter's inertial guidance system 200 miles from touchdown
as the spacecraft slows to Mach 7 (seven times the speed of
sound).
At landing minus six minutes, the
orbiter will enter what is referred to as the terminal area.
At this point its altitude is still quite high, 82,000 feet,
and its speed still supersonic at Mach 2.5. Its flight would
be akin to a conventional aircraft's except that the orbiter's
speed brakes will be left open to provide greater stability
during supersonic fight.
Approximately five minutes before
touchdown, the orbiter's speed would still be about Mach 1.
About four minutes before touchdown, the crew commander would
take over manual control of the spacecraft. This will be just
prior to a maneuver known as intercepting the Heading Alignment
Circle (HAC).
The HAC is a large turn to align
the orbiter with the centerline of the runway and to allow the
commander to bleed off any excess speed the vehicle may have.
At landing minus two minutes, the
orbiter would enter its final approach at an altitude of 13,000
feet. The speedbrakes would be closed at an altitude of 3,000
feet.
At an altitude of 1,800 feet and
7,500 feet from the threshold of the runway, the commander would
begin a pre-flare maneuver to pull up from a glide slope of
19 degrees to a gentler one of 1.5 degrees. Touchdown normally would occur
at a speed of about 300 knots per hour.
A
typical powerdown would be completed before the crew members exited
the orbiter, much the same as at a normal End-of-Mission (EOM)
landing. At a TAL site, this would take approximately 30 minutes
to accomplish.
At about T+3 hours (touchdown plus
three hours), the crew would depart the TAL site on board the
C-130 aircraft enroute to the hospital at Naval Station Rota,
Spain (if uninjured or only minor injuries) where they would
be met by the crew return aircraft from JSC for their return
to the United States.
If there were severely injured
crew members, they would be medevaced on the C-130 aircraft
or taken by ambulance to identified critical care medical facilities
in Europe. The crew members would remain together unless medical
circumstances or aircraft availability dictated otherwise.
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