A Guide to Measurement and Signature Intelligence (MASINT)

On the 3rd of April, 2023, NBC News confirmed through American official sources that the People’s Republic of China had collected and transmitted data signals emanating from American weapons systems [source]. The emanated signals could reveal the position or amount of missiles located in a specific base. They could even determine the presence of nuclear warheads. This method is called Measurement and Signature Intelligence, or MASINT, and it is argubably the most diverse form of intelligence collection.

1.0. What is MASINT?

The US’ Director of National Intelligence describes MASINT as “capturing and measuring the intrinsic characteristics and components of an object or activity” [source]. An example of this includes the use of antineutrino detection to track the use and development of nuclear reactors. This is a common technique in the specific subfield of nuclear MASINT [source].

MASINT has six subfields, many of which can overlap with each other or even with other fields of intelligence. These are:

• Radar MASINT uses radar to analyse and measure characteristics rather than to collect direct information as done in signals intelligence.
• Radiofrequency MASINT looks at transmitted information in radio transmissions that were unintentionally included, such as electromagnetic pulses.
• Materials MASINT uses remote sensing to determine information about materials used in a location or a system. This is done by finding and analysing background emanations from the relevant materials.
• Geophysical MASINT uses natural or man-made emanations on a wide range to determine changes or alterations to geography or weather. This field can revolve around detecting anything from meteorological changes to even finding buried structures.
• Nuclear MASINT traces radiation emanations to determine the presence and kind of nuclear activity in an area or system.
• Electro-optical MASINT complements imagery intelligence by using emanations to clarify the image, providing context and even identification of materials in an image through light sensors.

2.0. Why is MASINT important?

MASINT is a tool for not only states but also a variety of non-state or quasi-state actors, or even individuals. This is as the sensors utilised are often commercially available. Nuclear weapons inspectors use Geiger counters as a basic tool for inspections, for example. Civilians can buy the same Geiger counters through various easy access sources for cheap. Investigators use MASINT to confirm the use of chemical weapons, enforce treaty obligations on nuclear weapons, or track weapons deployments. 

Thanks to the variety of out-of-the-box uses for MASINT, it is a critical part of a state’s tradecraft toolbox. Its availability allows it to be used by almost any actor. Intelligence collection methods of other kinds will also gain greater detail through MASINT collection operations. MASINT, for example, is often used to reinforce imaging or signal collection. This can occur through the use of heat mapping, or sonar detection, to confirm visuals on submarines, for example.

3.0. How is MASINT collected?

The sensors that collect MASINT are diverse and complex, depending on the signatures and measurements being collected. One could use an electrometer to track usage of electricity and measure hours of activity, having purchased one for cheap. Alternatively, the United States has put millions of dollars to the development of friend-or-foe recognition for weapons to target autonomously.

Determining what needs to be measured in order to produce intelligence is the first step. Choosing a characteristic to measure depends on what intelligence needs to be collected. Despite this, each specific dataset will provide different benefits. Radiofrequency measurements will provide information on specific electronic devices and can find or assess intelligence on specific devices. Meanwhile, geophysical intelligence can provide intelligence on battlefield conditions. The means are determined by the ends.

4.0. Tips and tricks

MASINT can bypass security measures and the need for up close investigations in many scenarios, if deployed correctly. It often requires finding holes in security and defences, then matching a sensor type to this hole in defences. Such a tactic provides remote capabilities that would not otherwise be available. For example, using infrared at a distance has allowed law enforcement to trace drug production facilities [source].

Military sensor capabilities aren’t necessarily the most effective technology for conducting MASINT, nor the most sensible. Civilian and scientific equipment can often be cheaper or more effective than military specific hardware. Sometimes civilian equipment can be both cheaper and more effective for a particular operation. Sensor hardware in space used by scientific institutions, like NASA’s small scale cube-sat neutrino detector, allows for the use of these assets in heterodox methods. Through these, civilian organisations can conduct MASINT to support enforcement of obligations from the Treaty on the Non-Proliferation of Nuclear Weapons for example. They can do this by searching for man-made neutrino bursts that can come from nuclear programs, as one example.

Additionally, organisations use MASINT for business and economic interests. For example, civilian scientists have utilised the openly available satellite Gravity Recovery and Climate Experiment (GRACE) to sense gravity gradient tensors. Using these tensors, these scientists developed prediction engines that can reliably predict the position of oil deposits [source]. With a success rate of 96.1%, businesses can use this technique to find new oil deposits across the world. They can replicate the success of this technique through the use of other heterodox MASINT techniques. 

5.0. Common mistakes in MASINT

While MASINT is an extremely useful toolset with new capabilities appearing on the daily, there are many common pitfalls for new practitioners of the field. Those unfamiliar with prior mistakes should attempt to consider the angles from which this approach can fail, but these are common mistakes to avoid before approaching the field.

• MASINT remains a complementary toolset, not a replacement for signals intelligence, geospatial intelligence, or human intelligence. Attempting to use MASINT in a vacuum is likely to produce jumbled data without much direction. Interpreting such data will not only be nearly impossible, but unlikely to produce actionable intelligence.
• Using MASINT to plug holes in prior acquired intelligence is more effective than attempting to utilise it unplanned. By doing so, one can better determine which characteristics to measure and with what sensors.
• Commercial sources develop new sensor capabilities every year. Not being able to measure a specific characteristic with precision is not the end of the road. Keeping track of resources and developing capabilities will aid all MASINT operations.

6.0. Tools and resources

The International Spy Museum provides introductory courses on MASINT, taught by former US Foreign Service Officer Peter Humphrey.

7.0. Frequently Asked Questions

Some frequently asked questions about the field of MASINT are:

1. How do you best determine which measured characteristic is most relevant?

Figuring out what to measure, as step 1, can be the hardest. One way to determine the characteristic would be to rely on the most noticeable non-visual spectrum emanation of the target. Knowing what will blend into background noise is key, as heat mapping in uniform heat will provide little actionable intelligence

2. How do I know if my measurement sensors are precise enough?

Though contextual considerations can inform the technical capabilities needed from a sensor, such as the size of the target and background noise, it’s best to start with what remains available. An individual will likely have to rely on basic equipment, while states can deploy more complicated hardware off the bat. Lower quality measurements can still be of use.

3. What am I looking for in my measurement data?

The foremost matter to analyse in the data acquired is outliers. By identifying the averages and statistical shape of the background noise, outliers can be determined to be statistically significant, and these outliers will provide either intelligence that can be safely discarded to narrow the dataset, or the most relevant intelligence that would inform what to look for next.

8.0. Advanced techniques

States can deploy a much vaster arsenal of sensors and equipment for MASINT than individuals or even non-state actor organisations can. Satellite sensors can massively increase the long range and remote capabilities made available through usual MASINT techniques, allowing states to detect radiation or chemical weapons use through geospatial intelligence assets without a single operative nearing the zone of use. However, non-state actors can also access remote sensing capabilities. Commercial sensory cube-sats can cost less than $90,000 USD to deploy, affordable to organisations with sufficient capital. Additionally, organisations can contract commercial satellite companies with existing sensor satellite assets for satellite flyover operations.

On the other hand, operators can bend existing hardware’s capabilities in unique ways to produce new results from old or relatively primitive equipment. For example, Ukrainian radar targeted the Russian Federation’s flagship cruiser, the Moskva, far out of its intended range through bouncing radar off thick clouds [source]. Similarly, infrared sensors can also utilise the light bouncing techniques to expand the range of IR camera surveillance far past its intended range or ability. Though advanced equipment is useful, MASINT specialists push more primitive equipment beyond their limits in order to produce more actionable intelligence through such a MASINT source.

8.1. Using indirect MASINT

Finally, MASINT is more accessible than one might think on a tactical level, even without the ability of specialised equipment or sensors or satellite intelligence. Armies used indirect MASINT for millennia, despite most sensor capabilities having only existed for a century and a half at most. This is thanks to the many animals able to sense chemicals related to weather patterns days before these patterns materialise, and can serve as indirect indicators of changing conditions. As an example, high intensity weather events that could disrupt major tactical or strategic operations are spotted by meteorological data well in advance. Without such information, units pay attention to the movement of ground based mammals, as these will begin to leave a region due to changes in water and air pressure that indicate oncoming storms [source].

Organisations do not restrict these animals to blunt instruments as in the previous example either. States often train specific animals to better use their abilities to aid intelligence goals. For example, the United States Navy utilises dolphins with biological sonar abilities in its Marine Mammal Program to protect its naval base in Bangor, Washington, and defend what is the largest known stockpile of nuclear warheads in the world [source].

9.0. Case studies

As a primarily complementary discipline of intelligence collection, tradecraft operations almost always include MASINT investigations. Some primary examples of this are:

• Air operations use hyperspectral satellites to convert physical characteristics sensed of an area or system into spectrometric data, which the United States has deployed through its Joint Service Lightweight Standoff Chemical Agent Detector (JSLSCAD) to remotely detect the use of chemical weapons used on a battlefield [source]. The JSLSCAD checks imbalances in thermal infrared views of an area. Then, it compares the imbalances between background and gas temperatures to determine the presence of gas and the kind of gas being deployed [source].
• The US Defense Intelligence Agency’s Central MASINT Office (CMO) utilised MASINT of classified sources to find landing sites for Iraqi SCUD missiles in order to provide ground teams with tactical intelligence [source].
• The Romanian General Directorate for Defense Intelligence (DGIA) utilise satellite MASINT to complement imagery in the Black Sea to combat maritime terrorism [source].

10.0. Conclusion

Though often complementary to other forms of intelligence gathering, the wide ranging and out of the box tools available through the MASINT perspective of intelligence gathering make it an increasingly important toolset for state and non-state actors alike. Even more so, this toolset grows as new kinds of sensors mature as technologies, with new technology like ubiquitous sensing capabilities already changing the paradigm of nuclear weapons sensing. Keeping track of the scientific developments that are on the horizon will keep one aware of new capabilities in the field at all times.