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206 MEMS and Microstructures in Aerospace Applications

power, are the largest relative power consuming subsystems on small satellites. The
insight gained from these types of studies is that technologies which reduce both
power and mass of the GN&C subsystem will perhaps have the greatest propor-
tional potential to lower small spacecraft costs. Applying higher risk MEMS
technologies to the relatively costly and power consuming GN&C subsystems of
microsatellites, and other small-scale space platforms, is a technology thrust that
has potential for high payoff.
Furthermore, beyond developing technologies that simply reduce mass and
power, the community must also pursue in tandem the creation of architectures that
are modular and based upon commonly applied standards. When contemplating the
design of microsatellites to perform future science and exploration missions, many
space mission architects, space system engineers, and subsystem engineers all share a
common vision in which modular, adaptive and reconfigurable system technologies
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enable highly integrated space platform architectures. In the GN&C arena the design
of modular multifunction units is being investigated and researched, by both industry
and the government. Such units would effectively coalesce multiple GN&C sensing
and processing functions, and in some instances communications functions, into one
single highly integrated, compact, low-power, and low-cost device. Clearly MEMS
technology, along with other supporting avionics systems technologies, can be
exploited to enable this type of miniature GN&C hardware.
Such a unit would simultaneously provide autonomous real time on-board
attitude determination solutions and navigation solutions. This ‘‘GN&C in a box’’
device would operate as a single self-contained multifunction unit combining the
functions now typically performed by a number of hardware units on a spacecraft
platform. This approach, enabled by MEMS technology and advanced electronics
packaging methods, will significantly reduce the number of electrical, computer
data, and mechanical interfaces for the GN&C system, relative to current engineer-
ing practice, and should therefore payoff with dramatic reductions in costly and
time-consuming prelaunch integration and test activities. However, recognizing
the need to satisfy a variety of future mission requirements, design provisions
could be included to permit the unit to interface with externally mounted sensors
and actuators, as needed, to perform all necessary GN&C functions.
The desired result is a highly versatile unit that could be configured in multiple
ways to suit a realm of science and exploration mission-specific GN&C require-
ments. Three specific examples of modular multifunction GN&C technology de-
velopments are described in this section: the JPL MicroNavigator unit, the GSFC
Microsat Attitude and Navigation Electronics (MANE), and NASA’s NMP Space
Technology 6 (ST6) Inertial Stellar Camera (ISC) under development at Draper
Laboratory. The common design philosophy in all three cases is to merge the
GN&C sensing and data processing elements into a single unit by leveraging
advanced MEMS miniaturization and electronics packaging technologies. The
underlying shared goal is then to be in a position to mass produce these modular
GN&C units so that the overall cost of a next generation microsat is more afford-
able, relative to current production techniques. The evolution and eventual infusion
of these innovative miniaturized modular GN&C systems will rely heavily upon

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