Survivability is the ability to remain alive or continue to exist. The term has more specific meaning in certain contexts.

Ecological

Following disruptive forces such as

flood A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...

fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition ...

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

war War is an intense armed conflict between states, governments, societies, or paramilitary groups such as mercenaries, insurgents, and militias. It is generally characterized by extreme violence, destruction, and mortality, using regular o ...

, or

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

some species of

flora Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. E ...

fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoo ...

, and local life forms are likely to survive more successfully than others because of consequent changes to their surrounding

biophysical Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations. Bi ...

conditions.

Engineering

engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...

, survivability is the quantified ability of a

system A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, ...

, subsystem, equipment, process, or procedure to continue to function during and after a natural or man-made disturbance; for example a

nuclear electromagnetic pulse A nuclear electromagnetic pulse (nuclear EMP or NEMP) is a burst of electromagnetic radiation created by a nuclear explosion. The resulting rapidly varying electric and magnetic fields may couple with electrical and electronic systems to produce ...

from the detonation of a

nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...

. For a given application, survivability must be qualified by specifying the range of conditions over which the entity will survive, the minimum acceptable level or post-disturbance functionality, and the maximum acceptable

downtime The term downtime is used to refer to periods when a system is unavailable. The unavailability is the proportion of a time-span that a system is unavailable or offline. This is usually a result of the system failing to function because of an un ...

Military

In the military environment, survivability is defined as the ability to remain mission capable after a single engagement. Engineers working in survivability are often responsible for improving four main system elements: * Detectability - the inability to ''avoid'' being aurally and visually detected as well as detected by radar (by an observer). * Susceptibility - the inability to ''avoid'' being hit (by a weapon). *

Vulnerability Vulnerability refers to "the quality or state of being exposed to the possibility of being attacked or harmed, either physically or emotionally." A window of vulnerability (WOV) is a time frame within which defensive measures are diminished, com ...

- the inability to ''withstand'' the hit. * Recoverability - longer-term post-hit effects, damage control, and firefighting, ''capability restoration'', or (in extremis) escape and evacuation. The European Survivability Workshop introduced the concept of "Mission Survivability" whilst retaining the three core areas above, either pertaining to the "survivability" of a platform through a complete mission, or the "survivability" of the mission itself (i.e. probability of mission success). Recent studies have also introduced the concept of "Force Survivability" which relates to the ability of a force rather than an individual platform to remain "mission capable". There is no clear prioritisation of the three elements; this will depend on the characteristics and role of the platform. Some platform types, such as submarines and airplanes, minimise their susceptibility and may, to some extent, compromise in the other areas. Main Battle Tanks minimise vulnerability through the use of heavy armours. Present day surface warship designs tend to aim for a balanced combination of all three areas.

Naval

Survivability denotes the ability of a ship and its on-board systems to remain functional and continue designated mission in a man-made hostile environment. The naval vessels are designed to operate in a man-made hostile environment, and therefore the survivability is a vital feature required from them. The naval vessel’s survivability is a complicated subject affecting the whole life cycle of the vessel, and should be considered from the initial design phase of every war ship.Kotiranta, R., The Assessment of Naval Vessel’s Survivability against Explosion in Air based on a 3-D Product Model, 2006, p. 1 The classical definition of naval survivability includes three main aspects, which are susceptibility, vulnerability, and recoverability; although, recoverability is often subsumed within vulnerability. Susceptibility consists of all the factors that expose the ship to the weapons effects in a combat environment. These factors in general are the operating conditions, the threat, and the features of the ship itself. The operating conditions, such as sea state, weather and atmospheric conditions, vary considerably, and their influence is difficult to address (hence they are often not accounted for in survivability assessment). The threat is dependent on the weapons directed against the ship and weapon’s performance, such as the range. The features of the ship in this sense include platform signatures (radar, infrared, acoustic, magnetic), the defensive systems on board, such as surface-to-air missiles, EW and decoys, and also the tactics employed by the platform in countering the attack (aspects such as speed, maneuverability, chosen aspect presented to the threat). Vulnerability refers to the ability of the vessel to withstand the short-term effects of the threat weapon. Vulnerability is an attribute typical to the vessel and therefore heavily affected by the vessel’s basic characteristics such as size, subdivision, armouring, and other hardening features, and also the design of the ship's systems, in particular the location of equipment, degrees of redundancy and separation, and the presence within a system of single point failures. Recoverability refers to vessel’s ability to restore and maintain its functionality after sustaining damage. Thus, recoverability is dependent on the actions aimed to neutralize the effects of the damage. These actions include firefighting, limiting the extent of flooding, and dewatering. Besides the equipment, the crew also has a vital role in recoverability.

Combat vehicle crew

The crews of military

combat vehicle A combat vehicle, also known as a ground combat vehicle, is a self-propelled, weaponized military vehicle used for combat operations in mechanized warfare. Combat vehicles can be wheeled or tracked. History Ancient The chariot is a type of ...

s face numerous lethal hazards which are both diverse and constantly evolving.

Improvised Explosive Devices An improvised explosive device (IED) is a bomb constructed and deployed in ways other than in conventional military action. It may be constructed of conventional military explosives, such as an artillery shell, attached to a detonating mechan ...

(IEDs), mines, and enemy fire are examples of such persistent and variable threats. Historically, measures taken to mitigate these hazards were concerned with protecting the vehicle itself, but due to this achieving only limited protection, the focus has now shifted to safeguarding the crew within from an ever-broadening range of threats, including Radio Controlled IEDs (RCIEDs), blast, fragmentation,

heat stress Hyperthermia, also known simply as overheating, is a condition in which an individual's body temperature is elevated beyond normal due to failed thermoregulation. The person's body produces or absorbs more heat than it dissipates. When extreme ...

, and

dehydration In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...

. The expressed goal of "crew survivability" is to ensure vehicle occupants are best protected. It goes beyond simply ensuring crew have the appropriate protective equipment and has expanded to include measuring the overpressure and blunt impact forces experienced by a vehicle from real blast incidents in order to develop medical treatment and improve overall crew survivability. Sustainable crew survivability is dependent on the effective integration of knowledge, training, and equipment.

Prevention and training

Threat intelligence identifying trends, emerging technologies, and attack tactics used by enemy forces enables crews to implement procedures that will reduce their exposure to unnecessary risks. Such intelligence also allows for more effective pre-deployment training programs where personnel can be taught the most up-to-date developments in IED concealment, for example, or undertake tailored training that will enable them to identify the likely attack strategy of enemy forces. In addition, with expert, current threat intelligence, the most effective equipment can be procured or rapidly developed in support of operations.

Network

Definitions of network survivability

"The capability of a system to fulfill its mission, in a timely manner, in the presence of

threats A threat is a communication of intent to inflict harm or loss on another person. Intimidation is a tactic used between conflicting parties to make the other timid or psychologically insecure for coercion or control. The act of intimidation for co ...

such as attacks or large-scale natural disasters. Survivability is a subset of resilience." “The capability of a system to fulfill its mission, in a timely manner, in the presence of attacks,

failure Failure is the state or condition of not meeting a desirable or intended objective (goal), objective, and may be viewed as the opposite of Success (concept), success. The criteria for failure depends on context, and may be relative to a parti ...

s, or

accident An accident is an unintended, normally unwanted event that was not directly caused by humans. The term ''accident'' implies that nobody should be blamed, but the event may have been caused by unrecognized or unaddressed risks. Most researcher ...

s.”R. J. Ellison, D. A. Fisher, R. C. Linger, H. F. Lipson, T. Longstaff, N. R. Mead,
Survivable Network Systems: An Emerging Discipline
', Carnegie-Mellon Software Engineering Institute Technical Report CMU/SEI-97-TR-013, 1997 revised 1999

References

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