Unmanned Aircraft Systems Roadmap 2005-2030 - Federation of ...

UAS ROADMAP 2005
case of interception and exploitation of the data collected by the UA. All classes of UA are susceptible to
non-lethal threats.
While UA have been used in combat since the Vietnam War, combat and non-combat loss data is notably
sparse. With the proliferation of militarized UA in the last decade it is likely that a significant portion of
the information about UA combat experience is widely dispersed and undocumented. In addition, the
limited data that is readily available does not provide insight on subsystem/damage mode contribution to
combat loss or characterize the damage inflicted on UA that have returned from combat missions. Data
of this type regarding combat damage to manned aircraft since Vietnam have proven invaluable in
understanding the vulnerability of the aircraft and mitigating the threat. The systematic collection of
equivalent data for unmanned aircraft would be of equal benefit.
SURVIVABILITY AS A SYSTEMS DESIGN DISCIPLINE
DoD systems are intended to accomplish their mission in “a man-made hostile threat environment.” In
order to be mission effective, survivability must be considered; survivability becomes one of the design
factors in achieving the most mission effective system at the lowest cost.
Is it less costly to procure many inexpensive expendable UA, a few more expensive attritable UA, or even
fewer more expensive but more survivable UA? For manned systems, loss of human life is a
consideration that pushes the systems to a higher level of survivability. For unmanned systems this is not
the case. However, DoD UA still need to be effective and able to accomplish their missions in hostile
environments. To achieve that, survivability must be part of the design process. The extent that
survivability will be included in a design is dependant on many factors including the mission(s) to be
accomplished, the criticality of those mission(s), the threat environment that will be encountered, and the
number of assets available taking into account the UA aircraft as well as the payload. To perform a noncritical
mission in a low threat environment other aspects of the design (e.g., cost, range, or payload) will
take precedence over survivability features. This may also be true if a large number of expendable assets
are available to perform the mission. If one or more of the assets are destroyed, the mission can still
accomplished at lower life-cycle cost. A more critical mission in a higher threat environment increases
the importance of survivability design features. If few assets are available, completing the mission the
first time and with a single vehicle may be imperative. It is important to weigh all the factors in
determining how “survivable” a UAS must be to fulfill its specified functional capability.
By considering survivability early in the design process one can make design trade-offs and minimize the
potential cost and performance impacts. Modifications later in the design cycle will always come with
increased cost and performance penalties. If survivability is considered early in the design process there
are “no cost” design practices that will enhance a system’s survivability. An example is the placement of
critical systems to shield them from ground fire. No matter what decisions are made, considering all
facets of the design early will decrease the overall system life-cycle cost. For combat aircraft,
survivability must be a part of the trade space.
UNMANNED AIRCRAFT SYSTEM SURVIVABILITY CONSIDERATIONS
Regardless of size or cost, all UAS have the following functional components: (1) one or more aircraft,
(2) a system for command and control of the aircraft and associated payloads, (3) payload(s) and (4) a
means of disseminating the information obtained by the payload. Each of these functional components is
addressed separately below.
Aircraft
UA range in size from under one foot flying at 100 feet at 20 knots to those with wingspans over 130 feet
flying at 60,000 feet at 340 knots. A standard survivability approach will not work for all aircraft because
of this wide range of sizes and performance. Passive susceptibility reduction measures, such as visual and
acoustic signature reduction, may be the only way to increase the survivability of small aircraft due to
their limited size. Larger aircraft can support the introduction of active susceptibility reduction measures
APPENDIX K – SURVIVABILITY
Page K-2