A spacecraft previously designed
and flown by the Naval Research Laboratory (NRL) on a Titan IV
rocket has been selected by NASA to serve as the back-up Interim
Control Module (ICM) for the International Space Station
(ISS).
ICM will be mated with the ISS
via the Shuttle, and will reboost the ISS to higher orbits and
provide attitude and guidance control for the positioning of
the spacecraft. ICM may also provide a refueling capability that
could extend ISS operations for up to 3 years. Using this spacecraft
in combination with Clementine- and NASA-derived hardware designs,
NRL will be able to meet NASA's tight schedule for providing
a means to control the ISS during its critical "build-up"
stage and keep this major U.S. space program "on
track."
ICM, which was originally designed
by NRL's Naval Center for Space Technology (NCST) in the 1980's
to launch on NASA's Space Shuttle, was first named the Shuttle
Launch Dispenser (SLD). It was developed for and funded by the
National Reconnaissance Office.
The SLD program had passed its
Phase Two Safety Review at the time of the Challenger accident
in 1986. Subsequently, all Department of Defense missions were
directed to launch on expendable launchers. The SLD had to launch
on the then-new Titan IV, which necessitated that certain modifications
be made. At that time, the instrument was renamed the Titan Launch
Dispenser (TLD). The first TLD was launched from the Eastern
Test Range and therefore, the system has gone through all the
field processing and safety reviews required to load its 12,000
lbs of bi-propellant fuel and oxidizer.
The TLD program ended in 1996.
All residual hardware was retained by NRL for future potential
use. Modifications are now required to change the TLD into the
ICM needed for the ISS. TLD was spin-stabilized and ICM requires
three-axis stabilization.
Propellant management devices
will be added inside the propellant tanks and the attitude control
electronics will be changed to a three-axis design. NRL had previously
developed the three-axis Clementine spacecraft and many of those
designs and components will be used on ICM. Clementine also used
a 110-lb thrust main engine, which will replace the 900-lb engine
used on TLD. The Command and Data Handling will be changed to
make it ISS compatible and will include communications via tracking
and data relay satellite systems.
The U.S. Naval Research Laboratory is the Navy's full-spectrum corporate laboratory, conducting a broadly based multidisciplinary program of scientific research and advanced technological development. The Laboratory, with a total complement of nearly 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 85 years and continues to meet the complex technological challenges of today's world. For more information, visit the NRL homepage or join the conversation on Twitter, Facebook, and YouTube.
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