Packing up for a
cross-town move has never been easy, so it isn’t difficult to imagine
the headaches involved if the destination happens to be hundreds of
miles above the Earth, in orbit. Johnson Engineering, a NASA
contractor, owns this challenge in the packing of the Multi-Purpose
Logistics Modules, three Space Shuttle components used to transport
cargo to the International Space Station. To help tackle the problem
of packing thousands of pounds of electronic equipment, scientific
experiments and supplies into these space-age “moving vans,” Johnson
Engineering uses a software application developed with the Lisp-based
Allegro CL® product of Franz Inc.

Holding up to 10 tons of cargo each, the self-contained Logistics
Modules are designed to fit inside a Shuttle cargo bay. The complex
task of configuring and packing the Logistics Modules prior to launch
requires that careful attention be paid to many factors, such as
optimal fit, accounting for and evenly distributing the cargo weight,
and minimizing the possibility of breakage during transit. To automate
the packing process, Johnson Engineering relies on a revolutionary
Lisp-based computer program called the Cargo Planning, Analysis and
Configuration System (CPACs). With the CPACs application, the process
of planning and laying out an initial cargo configuration, which used
to take four technicians up to two weeks to accomplish, can now be
completed by one person in about six hours.

Originally developed by the Boeing Company for NASA, CPACs was
recently updated by software engineer Jason Kantz of Johnson
Engineering to support current cargo standards and specifications. In
benefiting from Lisp’s inherent capabilities such as automatic memory
management, manifest typing, first class functions, and closures,
Kantz believes that it was significantly easier to bring the CPACs
application up to date than if he had used a different programming

Although Kantz had developed in similar languages before, he had
never used Lisp prior to the CPACs project. Further, Kantz wanted to
integrate additional functionality and make the CPACs application
easier to debug. From his experience with Allegro CL, Kantz now
prefers Lisp over any other programming language, and he believes that
using Lisp makes applications much more flexible and easy to design,
especially for someone getting up to speed in a new language.

Said Kantz, “Lisp’s code-compile-debug cycle means that when I
re-write a function, I can instantly see how it effects the

Kantz continues to update the CPACs application, which will be
used for all future International Space Station re-supply missions.
He’s currently rewriting the application to remove many of the
pre-specified size and layout constraints. Lisp and Allegro CL are
well suited for this approach, because Lisp’s modular structure has
enabled Kantz to design a more generic loading model.

For more information on the CPACs application, visit

About Franz

Franz’s products enable developers to build complex, flexible and
scalable applications quickly, easily and cost-effectively. Founded in
1984, Franz has demonstrated consistent growth and profitability. For
more information, call 888/CLOS-NOW (510/548-3600 outside the
U.S.) or email

Note to Editors: Allegro CL is a registered trademark of Franz
Inc. Other trademarks and trade names are the property of their
respective owners.