JEC COMPOSITES MAGAZINE - Issue #78 - January/February 2013 - 53

aerospace

Construction of a CubeSat
using additive manufacturing
Additive manufacturing allows great design freedom. The more
complex the parts, the more useful this technique. The RAMPART satellite is a two-unit miniaturized satellite (2U CubeSat)
consisting of an upper bus module, a lower propulsion module
and solar panels. Here is a case study on this satellite, using the
state of the art in additive manufacturing technology.

Fig. 1: CAD view of RAMPART with panels

- Lower temperature = higher load
RAMPART’s solar panels will be springerected following the satellite’s deployment from its launch vehicle.

he entire structure (Figure
1), built from Windform® XT
material via additive manufacturing technology, is plated with a
high-phosphorus electroless nickel to
provide radar reflectivity for tracking
purposes. The upper bus module
consists of several experiments as well
as test solar cell panels mounted to
the exterior of the module. An additional experiment for performance
measurement of the Windform® XT
material is placed at the top section of
the bus (Figure 2).

Franco Cevolini, CEO, CRP Technology S.r.l.,
Walter Holemans, Planetary Systems Corporation,
Adam Huang, Department of Mechanical Engineering,
The University of Arkansas, Stewart Davis
Director of Operations, CRP USA, LLC,
Gilbert Moore, Project Starshine

Fig. 2: Top of bus module showing load cell (circled
in red)

The load cell (designed by Walter Holemans, Planetary Systems Corporation)
measures the change in preload of Windform® XT. A 180-kg compression load in
the load cell will cause 180-kg tension
and about 17 MPa stress in the material.
This integrated load cell is designed to
measure the creep or fracture resulting
from exposure to radiation and thermal
cycling over time.
- The excitation will be 10.0V, response
~0.002 V
- Response x calibration factor = load in
Windform® XT
- The load will vary with temperature and
time

The aft portion of the satellite consists
of a micro-electrical mechanical
(MEMS) propulsion system designed
and developed by Dr Adam Huang of
the University of Arkansas. The propulsion system incorporates a miniaturized
resistojet thruster core with a microfabricated de Laval nozzle and integrated
heater. Upstream of the nozzle/heater
assembly is an injector fed by 3 miniature
solenoid valves. Prior to arriving at the
valves, the propellant passes through a
2-phase separator membrane, where only
the gas phase of the liquid propellant
can pass through its micron-sized pores.
The membrane also serves as a filter for
preventing the valve seats from becoming
contaminated with debris. The propellant used is the R-134a refrigerant, which
is considered nontoxic and nonflammable. The compressed fluid nature of
R-134a provides relatively high self-pressurization for delivery throughout the
thruster system.
Although resistojets do not represent the

No78 January - February 2013

/ jec composites magazine 53

JEC COMPOSITES MAGAZINE - Issue #78 - January/February 2013

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #78 - January/February 2013