The Nostromo is an M-class
starship registered to Weyland-Yutani
Corporation out of the US state of Panama. It was refitted to be a
commercial towing vehicle in 2116, after which it has been largely
employed to run automated ore and oil refineries between the Sol
system and 20 Reticuli.
With a mass of 63,000 metric
tons, the Nostromo's spaceframe is based on
a modified Lockmart CM-88B Bison transporter. The Nostromo is designed
after a 6-10-4 layout, with three pressurized decks and four main cargo
holds. The spare volume is taken by the fuel tanks for the fusion
reactor and the reaction mass for the thrust engines. An off-axis
hooded frame mounts the docking latches for the towed cargo. The
Nostromo is sturdy enough of a vehicle to withstand atmospheric
re-entries and surface landings, for which it is supported by three
main landing
shock absorbers. The micrometeorite and particulate shielding is
sufficient
to withstand rough re-entries.
All of the in-flight systems are
controlled by the central "Mother"
processor. Mother is a 2.1
Terabyte intelligent mainframe which monitors
all of the ship's flight and autonomous functions. A 2.0 Terabyte
backup
mainframe comes on line in the event of a CPU failure, and a third tier
of
automatics is also capable of sustaining autonomic functions, should
the backup fail as well.
The communications system is
standard, comprised of one 10- and one 4-meter
hyperstate antenna for any interstellar communications and short-range
EHF/UHF/VHF/HF radio/video links. 
The sensors are mounted on
pylons which
are clustered around the forward hull of the ship and are fitted with: two 2-m
aperture telescopes which are capable of optical, spectrographic and
infrared resolution; a gas chromagraph; centimetric and millimetric navigation and
landing radar; a synthetic aperture ground mapping radar; and a mass
counter for supralight navigation.
The Nostromo's power core is a Laretel WF-15 2.8 Terawatt fusion
reactor. The fusion process is a deuterium/tritium reaction that can
fuse the
fuel elements in a containment chamber using conversion lasers. 
The He4
byproduct of the reaction is kept separately and is vented at regular
intervals. The power is drawn off of the reactor by a closed-cycle
liquid potassium cooling system. This runs off into a induction torus
which can use the intense magnetic field created by the superheated
potassium to generate electric power. The ship may be destroyed by an
authorized crewmember by overriding the reactor cooling system and
bleeding
off the coolant, which initiates a supercritical reaction in the
containment
area. After the activation of the self-destruct system, the crew has
ten
minutes to get far enough from the ship before the reactor explodes.
The supralight drive is a Yutani
T7A NLS tachyon shunt which is capable
of unladen high cruise up to 0.42 ly per sidereal day (153 cee). When
it
is towing large amounts of cargo such as automated refineries, the
maximum sustainable cruise speed drops radically to about 0.1-0.12 ly per
sidereal day (40-45 cee). For manuvering at sublight speeds when towing
large amounts of cargo, the immensely poweful mass reaction engines are
required. On the Nostromo, the original Saturn J-3000 engines have been
replaced by two Rolls-Royce N66 Cyclone thrust tunnels with bipolar
vectoring for midline lifting functions. Each of the powerplants
develop
a 65,830 metric tons of thrust, using water for reaction mass. When
running wide open, both of the engines give a high impulse thrust total of 131,760 kN.
The life-support systems comprise three decks, which include the bridge,
crews
quarters, and dining area. Other areas include the science station, the CPU
module, medical bays, four main cargo bays, storing areas, and the
engineering stations. All of these comprise 1.1 million cubic meters
of pressurized volume, including all of the air ducts and the air
scrubbing plant. The Nostromo has a crew of seven: Ship's Master, First
Officer, Executive Officer, Navigation Officer, Science Officer, Chief
Engineer, and Engineer's Mate. There are seven hypersleep capsules that
have been installed for the long-duration flights. The polarized gravity
generators provide the internal gravity and the internal dampening.
Beneath the hull, there is an external docking bay for a shuttlecraft. The
shuttlecraft is capable of serving as a lifeboat when evacuation of the ship is
neccessary.
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