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Microtechnologies for Space Systems 123

TRL gap manifests itself. The reason mid-TRL development is such a dreaded
phase is because a successful transition to high TRL depends on several techno-
logical and programmatic factors that have to come together in the correct se-
quence. The ultimate objective for the TMT at the mid-TRL stage is to change the
character of the new technology from ‘‘push’’ to ‘‘pull’’ — and thereby create a
customer demand. The TMT approach can potentially increase significantly the
number of new technologies transitioned and the overall efficiency of the transition
process. Recently, there has been recognition at the international level of this need
to bring together the disparate communities involved in aerospace technologies
under one roof. 22

6.3.2 LOW-COST,RAPID SPACE FLIGHT
A novel solution developed to overcome the ‘‘TRL Gap’’ problem has been to fly
MNT-based devices at the low TRL stage of development. It is hoped that such
flight demonstrations will generate the necessary space heritage required for future
NASA, military, and commercial spacecrafts. By having space flights at the low-
TRL stage, one can either ‘‘screen’’ the technology for space-worthiness or alter-
natively, build in the requisite robustness, far more cheaply and cost-effectively,
than at higher TRLs. Screening space-suitable devices at an early stage in the
development cycle avoids wastage of effort and investment over several years
into technological ‘‘dead-ends.’’ On the other hand, design changes are often
necessary to make MNT devices and systems comply with the form, fit, and
functional requirements of space missions. These design changes could be identi-
fied and implemented based on lessons learned from the space flight experiment.
The primary limitations to obtaining space heritage for new technologies are the
limited flight opportunities that are available and the conservatism of mission
managers to the infusion of technologies not tested in space. This risk-averse
conservatism is understandable since an average space mission costs several hun-
dreds of millions of dollars and therefore has to have a low probability of technol-
ogy-related failure. Therefore, until recently, the only option for new technologies
was to conduct extensive reliability testing in terrestrial laboratories, and if possible,
by simulating the expected space environment.
An important innovation that makes the testing of new technologies in space
competitive with terrestrial laboratory testing is the development of the low-cost,
rapid-launch PICOSAT spacecraft. The PICOSAT has also spawned the worldwide,
university-based CubeSat program mentioned above. The PICOSAT is an invention
of the Aerospace Corporation 23 and is developed primarily as a rapid-launch, low-
cost platform for testing new technologies and mission architectures in LEO. The
24
MEMS technology group at JPL partnered with the Aerospace Corporation, under
sponsorship from the Defense Advanced Research Projects Agency (DARPA) and
AFRL to develop a 1 kg class (10 10 12.5 cm) PICOSAT spacecraft. The 10
10 cm cross-section for the satellite and the type of spring-loaded launcher devel-
oped for ejecting the PICOSAT has been adopted as the standard by the CubeSat
program. Once released in orbit, the PICOSAT is designed to be fully autonomous,

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