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208 MEMS and Microstructures in Aerospace Applications

The MANE design concept was an outgrowth of earlier work on a multifunc-
8
tional GN&C System (MFGS) performed at GSFC. The mass and power resource
requirement goals for the MFGS were 2.5 kg and 12 W, respectively. While the
MFGS design represented substantial improvement in overall GN&C subsystem
resource requirements, the MANE concept was developed to drive the MFGS
design to the next level of miniaturization with an ultimate, long-term, high-risk
goal of developing an ultra-miniature design that captures the MFGS performance
in a volume of several cubic inches employing MEMS microsystems, advanced
space avionics electronics packaging or assembly technologies together with the
ultra low power (ULP) electronics technology being pioneered by the University
9
of Idaho and GSFC. The very space-efficient chip-on-board (COB) technology,
pioneered by the Johns Hopkins University Applied Physics Laboratory (JHU/
APL), was identified as a viable initial technique to achieve the miniaturization
goal for MANE. COB achieves up to 10 higher circuit density by attaching bare
die directly to the underlying board.
The MANE performance capabilities will largely depend on the individual
mission requirements and the available set of navigation and attitude sensor data.
The MANE design utilized a single reusable GN&C software system architecture
for which the performance capabilities can be tailored for individual missions
obviating the need for expensive new flight software design and development.
Attitude determination performance goals for the MANE ranged between 0.1 and
0.38 without the external star sensor data and 1–2 arc-seconds with the external
star sensor data. The MANE design goals were to achieve power consumption of
less than 3 W, a unit mass of less than 1 kg in a total volume of less than 10 cubic
inches.

10.2.3 NMP ST6 INERTIAL STELLAR CAMERA
NASA’s NMP is sponsoring the development of the Inertial Stellar Compass (ISC)
space avionics technology that combines solid-state MEMS inertial sensors (gyro-
scopes) with a wide field-of-view APS star camera in a compact, multifunctional
package. 10 This technology development and maturation activity is being per-
formed by the Charles Stark Draper Laboratory (CSDL), for a Space Technology
6 (ST6) flight-validation experiment now scheduled to fly in 2005. NMP missions
such as ST6 ISC are intended to validate advanced technologies that have not yet
flown in space in order to reduce the risk of their infusion in future NASA missions.
The ISC technology is an outgrowth of earlier CSDL research focused in the areas
of MEMS inertial device development, 11 MEMS-based GN&C sensors and actu-
ators, 12 and low-power MEMS-based space avionic systems. 13
The ISC, shown in Figure 10.1, is a miniature, low-power, stellar
inertial attitude determination system that provides an accuracy of better than 0.18
(1-Sigma) in three axes while consuming only 3.5 W and packaged in a 2.5 kg
housing. 14
The ISC MEMS gyro assembly, as shown in Figure 10.2, incorporates CSDL’s
tuning fork gyro (TFG) sensors and mixed signal application specific integrated

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