With the war in Ukraine progressing, and calls for prosecution of war crimes becoming louder, the use of the all-important satellite data as evidence in court becomes an important topic. Even though the reliability of satellite data seems obvious, its use in legal situations is subject to questions about its validity and reliability. The book ‘Evidence from Earth Observation Satellites‘ (2012), edited by Ray Purdy, is one of the standard works describing how satellite data can be used in court.
The following paragraphs are excerpts from two chapters of this book, describing the use of Earth Observation (EO) data at international level, reproduced here with written approval of the editor.
History of the use of satellite data in court
When the United Nations (UN) Principles Relating to Remote Sensing of the Earth from Space were adopted in 1986 at the 41st Session of the UN General Assembly (UNGA 41/65), the development of Earth Observation Satellites and the speed at which this technology has grown, were hardly in the minds of the drafters of those Principles, let alone the international community or the detached observer. Nowadays, in most countries – industrialised or otherwise – the use of EOS is routine.
Although the use of Earth Observation data has been increasingly common in international disputes, starting with the frontier dispute between Burkina Faso and Mali as early as 1986, it has never been as visible and widely published in the media as in the current war between Russia and Ukraine.
Legal admissibility of satellite imagery
It would seem that the use of satellite imagery in international disputes is a no brainer. However, reality is different. The key issue here is the perceived reliability of satellite data as unbiased evidence in court.
This became obvious in the border dispute in Africa described earlier. In its conclusion, the International Court of Justice (ICJ) held, in no uncertain terms, that satellite maps could not constitute a binding document or a territorial title by themselves, whatever their accuracy and technical value, unless the parties concerned had expressed their acceptance. Those maps, it was asserted, had no greater legal value than that of endorsing a conclusion at which a court had arrived by other means. Hence, they could not be seen as evidence of a frontier, nor be given the character of a rebuttable (juris tantum) presumption leading to a legal title.
As pointed out by Niklas Hedman in an Introductory Report for the Space Law Committee of the International Law Association (ILA) prior to its 2004 Berlin Conference, a remote sensing image submitted to court is the result of a long chain of measures, open to different interpretations. This situation calls for caution in the evaluation by the court of the satellite data provided.
Stages of satellite imagery collection
At the root of the question is the fact that even though digital mapping allows almost no margin for human error in the production of a satellite image, there is plenty of space for error in the interpretation of the image.
Briefly, the different stages in the collection of data from space are as follows:
- Earth observation satellites collect the raw (primary) data which they send to ground stations. In this primary phase, the data has no real value and should be processed.
- The first step – known as pre-processing – is to correct, among other things, atmospheric, radiometric and geometrical distortions.
- Next, the raw data becomes available in digital form and certain aspects of the picture may be enhanced, at the user’s request, by means of computers.
- The user may then ask for the classification of the information gathered, bringing together, for instance, similarities and differences.
- Ancillary information, such as maps, may be added to prove the results of the satellite image.
Therefore, the end product submitted to court is the result of a long chain of interpretations and changes. It is a fact that, by obscuring or enlarging a satellite image beyond the proper resolution, programmes like Photoshop may generate extra pixels and, therefore, modify the image.
The issue of data manipulation
The difficulties are linked to the very nature of satellite imagery, which normally consists of data and not photographs proper. This point is essential where evidence is concerned. When dealing with numbered images that are merely a list of data, this can be modified without possibility of detecting forgeries at a later stage. On this assumption, and taking into account the techniques presently available, it is imperative to supervise the process of obtaining the image from the moment it is collected as primary data right up to the time it is used in court.
When considered the one and only means of evidence in legal proceedings, satellite imagery and its value at the evidence stage appear to carry an aura of suspicion given the possibility for forgery. Contrary to what occurs in traditional aerial photography, changes to satellite imagery are not detectable at later stages.
Nevertheless, satellites are a powerful source of scientific evidence useful in environmental litigation and regulation. Its relevance in international litigation has gradually but visibly developed over the years and gained recognition among judges and lawyers alike. The use of satellite imagery as a surveillance tool is already expressly authorized in some European Community legislation, where its use by Member States to monitor claims for farm subsidies and fish catches is permitted.
In the United States special guidelines known as the “Daubert Standard” exist for admitting novel scientific evidence based on expert testimony in court, including satellite imagery products. According to this standard, specific requirements need to be met:
- Has the technique been tested in actual field conditions (and not just in a laboratory)?
- Has the technique been subject to peer review and publication?
- What is the known or potential rate of error? Is it zero, or low enough to be close to zero?
- Do standards exist for the control of the technique’s operation?
This standard has helped enable the use of satellite imagery in national criminal cases in the US. In 2005, the state of Arizona, for instance, used high resolution satellite imagery – IKONOS – to reveal that a Scottsdale land developer illegally cleared state and private land. A comparison of satellite images taken before and after the alleged clearing of the site highlighted discrepancies and hence the offence.
Additionally, the Daubert Standard, or similar criteria, have been adopted by other countries, and is sometimes referred to in international criminal cases, as a way to help prosecutors assess the accessibility of satellite data in international cases.
Use of satellite imagery in the International Criminal Court (ICC)
On 17 July 1998, 120 states adopted the Rome Statute, which established The International Criminal Court, commonly referred to as the ICC. It is a permanent tribunal established by the Assembly of States Parties to prosecute individuals for genocide, crimes against humanity, war crimes and crimes of aggression. The Rome Statute, the legal basis for the Court, came into force on 1 July 2002.
As standard procedure, the ICC Office of the Prosecutor always looks into the applicability and usefulness of EO technologies in all cases being dealt with by the Office. Satellite imagery contains information that can be used as hard or corroborative evidence to prove cases in court.
For cases falling within the mandate of the ICC, the Office of the Prosecutor normally seeks EO technological evidence, such as available satellite imagery, to prove the following activities:
- Destruction of properties;
- Attacks against civilian objects;
- Attacks against personnel, installations, material, units or vehicles involved in a humanitarian assistance or peacekeeping mission in accordance with the Charter of the United Nations;
- Attacking or bombarding towns, villages, dwellings or buildings that are not military objectives;
- Identification of military infrastructures, military personnel;
- Primary, secondary and tertiary mass graves;
- Fires and arsons;
- Road blocks in conflict situations;
- Transfer of people and refugee camps;
- Disturbances of the natural state of the earth’s surfaces which can imply human activities such as mass graves in conflict situations;
- Bomb craters;
- Mass groups of people such as demonstrations in conflict situations.
Once an investigation is started, the ICC will identify whether satellite imagery is available in the archives of providers for the specific place(s) and date(s) of interest. In order to do this, an EO specialist in the ICC Office of the Prosecutor (OTP) liaises with external partners (either one of the organisations with whom an agreement is already in place, or a commercial vendor) to assess the availability of imagery.
Based on the findings as related to the source of the imagery, available imagery will be analysed, either in-house or externally by one of the external parties. Provided the analysis is an internal product, a peer review is then carried out by one or more external parties in order to validate the results. Afterwards, the analysis report goes through a series of reviews, to ascertain its evidential value.
Legal basis for the admissibility of EO data in ICC cases
The Rome Statute defines War Crimes as it is related to circumstances in both international and internal conflicts. The spatial component articulated about these crimes and the rules of procedures paves the way for the use of EO technologies by the OTP as evidence used in court. The Rules of Procedure and Evidence to the ICC prescribe how EO data can then be used.
A large amount of literature available on open source references indicates that EO technologies are widely applicable and acceptable as material evidence in international courts of law. The technique has developed tremendously over the years, thanks to ground-breaking advances in the fields of remote sensing, photogrammetry and computer science. In the last couple of decades, EO technologies have made inroads into the legal field and keep gaining recognition and acceptance amongst international and national judicial systems.
Earth Observation technologies are being used in the ICC OTP with a view to meeting existing international standards followed by other international legal institutions – such as the ICJ and the ICTY among others. The technology is also used to meet best practices as enunciated in the Daubert standards and to raise the quality of evidence to prove that the crimes in question were indeed committed.
EO technologies and, in particular, satellite imagery, has played, and will continue to play, an important role in the opportunities available to the OTP in its quest to search for objective sources of evidence to prove the cases brought before the court. It serves both as hard material evidence and corroborative evidence which raises the quality of other evidence. As an investigation tool, it helps investigators gain insight into the spatial aspects of the situation they are dealing with, verify the reliability of some of the statements made by material witnesses and to generally understand what is where and at what time.
EO technologies have been widely used in order to find objective evidence related to the presence of military activities, tell-tale evidence related to mass graves, illegal roadblocks in conflict situations, scorched marks associated with fires and arsons, disturbed earth surface material related to human activities, bomb craters and extensive destruction of property such as dwellings, towns, villages or buildings.
Can satellite imagery still prove war crimes (by Pierre Hazan)