[Editors] MIT models interplanetary supply chain

[Elizabeth Thomson]

MIT News Office
Massachusetts Institute of Technology
Room 11-400
77 Massachusetts Avenue
Cambridge, MA  02139-4307
Phone: 617-253-2700
http://web.mit.edu/newsoffice/www

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MIT models interplanetary supply chain
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For Immediate Release
THURSDAY, MAR. 22, 2007
Contact: Elizabeth A. Thomson, MIT News Office
Phone: 617-258-5402
Email: thomson at mit.edu

PHOTO, GRAPHICS AVAILABLE

CAMBRIDGE, Mass.--If you think shipping freight from Cincinnati to El 
Paso is challenging, imagine trying to deliver an oxygen generation 
unit from the Earth to a remote location on the moon.

By 2020, NASA plans to establish a long-term human presence on the 
moon, potentially centered on an outpost to be built at the rim of 
the Shackleton crater near the lunar South Pole.

To make such a scenario possible, a reliable stream of consumables 
such as fuel, food and oxygen, spare parts and exploration equipment 
would have to make its way from the Earth to the moon as predictably 
as any Earth-based delivery system.  Or more predictably: One missed 
shipment could have devastating consequences when you can't easily 
replenish essential supplies.

To figure out how to do that, MIT researchers Olivier L. de Weck, 
associate professor of aeronautics and astronautics and engineering 
systems, and David Simchi-Levi, professor of engineering systems and 
civil and environmental engineering, created SpaceNet, a software 
tool for modeling interplanetary supply chains. The latest version, 
SpaceNet 1.3, was released this month.

The system is based on a network of nodes on planetary surfaces, in 
stable orbits around the Earth, the moon or Mars, or at well-defined 
points in space where the gravitational force between the two bodies 
(in this case, the Earth and the moon) cancel each other out. These 
nodes act as a source, point of consumption or transfer point for 
space exploration logistics.

"Increasingly, there is a realization that crewed space missions such 
as the International Space Station or the buildup of a lunar outpost 
should not be treated as isolated missions, but rather as an 
integrated supply chain," said de Weck. The International Space 
Station already relies on periodic visits by the space shuttle and 
automated, unpiloted Russian Progress re-supply vehicles.

While "supply chain" usually refers to the flow of goods and 
materials in and out of manufacturing facilities, distribution 
centers and retail stores, de Weck said that a well-designed 
interplanetary supply chain would operate on much the same 
principles, with certain complicating factors. Transportation delays 
could be significant-as much as six to nine months in the case of 
Mars-and shipping capacity will be very limited. This will require 
mission planners to make difficult trade-offs between competing 
demands for different types of supplies.

A reliable supply chain will "improve exploration capability and the 
quality of scientific results from the missions while minimizing 
transportation costs and reducing risks" to crew members, de Weck 
said.

SpaceNet evaluates the capability of vehicles to carry pressurized 
and unpressurized  cargo; it simulates the flow of vehicles, crew and 
supply items through the trajectories of a space supply network, 
taking into account how much fuel and time are needed for 
single-sortie missions as well as multiyear campaigns in which an 
element or cargo shipment might have to be prepositioned by one set 
of vehicles or crew members while being used by another.

In addition to determining a logical route, SpaceNet also allows 
mission architects, planners, systems engineers and logisticians to 
focus on what will be needed to support crewed exploration missions.

To experience an environment as close as possible to harsh planetary 
conditions, MIT conducted an expedition to Devon Island in the 
Canadian arctic in 2005. The researchers established a semi-permanent 
shelter at the existing NASA-sponsored Haughton-Mars Research Station 
(www.marsonearth.org) and compiled an inventory of materials at the 
base, including key items such as food, fuel, tools and scientific 
equipment, while carefully tracking inbound and outbound flights.

They also experimented with modern logistics technologies, such as 
radio frequency identification, that autonomously manage and track 
assets with the goal of creating a "smart exploration base" that 
could increase safety and save astronauts and explorers precious time.

SpaceNet 1.3 is written in MATLAB, a high-level technical computing 
language and interactive environment for algorithm development, data 
visualization, data analysis and numerical computation.

The SpaceNet development team includes MIT graduate students, 
postdoctoral associates and research staff led by de Weck and 
Simchi-Levi, aided by partners at Caltech's Jet Propulsion 
Laboratory; Payload Systems Inc., which provides science and 
engineering services for spaceflight applications; and NASA industry 
partner United Space Alliance.

For more information on SpaceNet 1.3, go to spacelogistics.mit.edu.

This work was funded by NASA.

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