A Proposal to Read the Green Sahara to Find Humanity's Roots
Reading the Green Sahara
Unlocking West Africa's Buried Prehistory with
Unmanned Aerial SAR, LiDAR, and AI-Assisted Analysis
A Proposal for a Civilian Science Program
Addressing one of archaeology's last great frontiers through technology already proven in defense applications — and already flying on civilian NASA science missions.
April 2026 • Concept Proposal v1.0 • DISTRIBUTION: LIMITED
This program proposes to do for West African prehistory what the PACUNAM LiDAR Initiative did for the Maya lowlands and what the University of Leicester's satellite surveys did for the Garamantes civilization in Libya — to reveal, non-invasively and at landscape scale, a human story that ground survey alone cannot recover.
The current security situation in Mali, Niger, and Burkina Faso — where active insurgencies have suspended most ground-based archaeological fieldwork — makes this remote-sensing-first approach not merely advantageous but essential. The proposed platform can operate from bases entirely outside hostile airspace, collecting data now for ground-truth verification when political conditions permit.
The African Humid Period (AHP, approximately 14,800–5,500 years before present) transformed the Sahara into a green, populated landscape crossed by rivers and lakes. Earth's axial precession cycle — the same 'wobble' that slowly alters the angle of Earth's tilt over 26,000 years — drove the monsoon southward and produced the hyperarid Sahara we know today. This was not a gradual fade; recent work from the Chew Bahir basin (Wolff et al., Nature Communications, 2024) documents that the transition was punctuated by violent drought episodes recurring roughly every 160 years, each driving a pulse of human displacement southward.
The populations who had spent millennia exploiting the AHP's lakeshores and river floodplains carried hydraulic expertise, pastoral skill, and long-distance trade relationships into the Sahel. The Niger River's inland delta — with a cultivation zone more than five times the size of the Nile Delta — provided an ecological template onto which these incoming communities could map their knowledge. The result, over two millennia, was the emergence of West Africa's great urban civilizations: the cities of Djenné-Djenno (occupied from 250 BCE), Gao, and Timbuktu, and the imperial sequences of Ghana, Mali, and Songhai.
What the Landscape Contains — and Why It Hasn't Been Found
The terrain between the southern Saharan edge and the Niger River corridor contains:
Buried paleochannels — former rivers and lake drainage systems from the AHP, now covered by aeolian sand, detectable by L-band SAR penetration at depths of 1–5 meters. The first such 'radar rivers' were detected by NASA's SIR-A shuttle mission in 1981 (McCauley et al., Science).
Settlement mound complexes — the Inland Niger Delta alone contains hundreds of raised occupation mounds comparable to Djenné-Djenno, most unsurveyed. LiDAR can resolve their micro-topography at sub-meter resolution.
Trans-Saharan caravan routes — ancient track networks pressed into desert hardpan by millennia of camel caravans are detectable as SAR backscatter anomalies, a technique that located the lost city of Ubar in Oman (NASA JPL, 1992).
Prehistoric habitation around paleo-lake margins — analogous to the Gobero cemetery site in Niger (Sereno et al., PLoS ONE, 2008), where 5,000 years of AHP settlement was preserved around a vanished lake.
None of this landscape has received systematic LiDAR survey. A 2025 systematic review (Vinci et al., Archaeological Prospection) confirmed that LiDAR application in West Africa remains virtually absent from the published scientific literature — the most dramatic geographic gap in the global archaeology of the past two decades.
NASA UAVSAR on Global Hawk — The Existing Capability
NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) program, managed by JPL, has operated continuously since January 2009. The UAVSAR is a reconfigurable, pod-based L-band fully polarimetric SAR explicitly designed to serve as NASA's airborne science facility instrument. Its stated mission applications include archaeological research, soil moisture mapping, geology, and vegetation classification. It has already been ported to the Northrop Grumman Global Hawk platform, with two wing-mounted pods enabling single-pass polarimetric interferometry and precision topographic mapping.
The Global Hawk's capabilities make it uniquely suitable for this mission:
Operational range of ~14,500 km — sufficient for round-trip survey of the entire Niger Bend from Dakar (Senegal) or the Azores, with no basing agreement required within the currently unstable Sahel states
Nominal flight endurance of 22–30 hours — enabling complete area survey of the Niger Bend, Inland Delta, and Saharan paleochannel network in a single extended sortie
Operational ceiling of 65,000 feet — providing wide-swath SAR coverage while maintaining safe separation from other traffic
No aircrew at risk — operationally decisive given the active insurgency environment in Mali, Niger, and Burkina Faso
GA-ASI's Contribution: The Lynx SAR Heritage and the SkyGuardian Option
General Atomics Aeronautical Systems brings capabilities that directly complement the NASA platform. The GA-ASI AN/APY-8 Lynx II SAR, already integrated on the MQ-9A Reaper, is a high-resolution multi-mode radar with spotlight and strip-map SAR modes and a heritage of thousands of operational flight hours. GA-ASI's experience in sensor pod integration, precision navigation for repeat-pass interferometry, and Ku-band satellite data links for real-time downlink is directly applicable to archaeological survey operations.
Should the NASA Global Hawk not be available for international science campaigns during the proposed survey window, the GA-ASI MQ-9B SkyGuardian — the certified civil variant of the Reaper with FAA Type Certificate and STANAG 4671 compliance for non-segregated airspace — represents an immediately available alternative platform. The SkyGuardian's 40+ hour endurance and 360 kg internal payload capacity can accommodate the UAVSAR pod or an equivalent civilian L-band SAR instrument alongside a survey-grade LiDAR and hyperspectral imager in a single integrated payload.
The proposed program draws on the two research groups with the deepest expertise in Niger River basin archaeology and Saharan remote sensing respectively.
Rice University / Yale University — McIntosh Group
Prof. Susan Keech McIntosh (Rice University, Herbert S. Autrey Professor Emerita of Anthropology) and Prof. Roderick J. McIntosh (Yale University, Department of Anthropology) are the world's foremost authorities on Niger River basin archaeology. Their excavations at Djenné-Djenno, begun in 1977, established that sub-Saharan urban complexity predated Arab contact by more than a millennium. Their most recent publication (Azania, 2025) reports ongoing excavation results from the medieval town of Jenné in collaboration with Mali's Direction Nationale du Patrimoine Culturel. Their 2023 Azania paper on the Dia settlement mound complex adds new AMS dates to a 1986–87 dataset — demonstrating active, continuous research engagement with exactly the landscape this program proposes to survey.
The McIntosh group's excavated sites across the Inland Niger Delta — Djenné-Djenno, Dia, Hambarketolo, Kaniana — provide an unparalleled calibration dataset for tuning remote sensing algorithms to the specific sedimentary and architectural signatures of West African mound-site archaeology.
University of Leicester — Mattingly Group
Prof. David Mattingly's team at the University of Leicester produced the definitive demonstration of satellite archaeology's potential in the Saharan region: the discovery of more than 100 previously unrecorded Garamantes fortress settlements in Libya's Fezzan region using commercial satellite imagery and 1950s aerial photography. This EU-funded project (Desert Migrations / Trans-Saharan Archaeology) showed that a civilization previously known only from a single excavated capital was in fact densely distributed across the landscape. The Leicester group brings both the remote-sensing methodology and the trans-Saharan historical framework essential for interpreting what UAVSAR data will reveal.
Three-Phase Implementation
The following represents a preliminary budget estimate for the full 48-month program. Detailed cost breakdown will be developed during Phase I consortium formation.
The program is structured to attract NASA Science Mission Directorate funding through the Earth Science Division's Airborne Science program, which already funds UAVSAR campaigns for Principal Investigators. The paleoclimate framing — studying the African Humid Period termination through its landscape signature — is squarely within NASA's Earth Science mandate. The archaeological dimension adds public engagement value and aligns with NSF's current priorities in human-environment interaction research.
West Africa's deep past is one of the most consequential and least understood chapters of human history. The empires of Ghana, Mali, and Songhai commanded trade networks stretching from the Mediterranean to the Gulf of Guinea, produced one of the world's greatest concentrations of medieval manuscripts, and demonstrated forms of political pluralism and urban organization that had no parallel elsewhere. Their origins lie in the human migration forced by the Sahara's formation — a migration whose physical traces are now accessible to radar from altitude.
The manuscripts of Timbuktu — an estimated 700,000-plus texts spanning the 12th through 20th centuries, recently returned to the city after a harrowing rescue operation during the 2013 jihadist occupation — represent the written record of this civilization. The buried landscape record is its physical complement. Together, they offer the possibility of understanding one of humanity's great civilizational traditions in its full ecological and historical depth.
This is also a story about technology serving humanity in its deepest sense. The same platform family that helped locate Osama bin Laden can, with appropriate instruments and intent, locate the buried cities of Africa's greatest empires. The radar that watches borders can read buried rivers. The sensor that tracks moving targets can find the traces of people who walked these landscapes ten thousand years ago.
Heinrich Barth arrived at the ruins of Gao in 1858 and could only see what the surface showed him. We now have the tools to see what is underneath. The question is whether we will use them.
Exploratory meeting between GA-ASI senior leadership, NASA JPL UAVSAR program management (Scott Hensley group), and archaeological Principal Investigators (McIntosh group, Rice University) to assess instrument compatibility and platform availability.
Legal and compliance review: ITAR/EAR applicability to civilian science deployment; FAA certificate of authorization requirements; State Department notification for UAV operations in African airspace.
NASA SMD Earth Science Division pre-proposal consultation: assess fit with Airborne Science Program solicitation calendar; identify appropriate program element (ROSES or directed).
GA-ASI Green Foundation / philanthropic program: assess whether the Green Foundation (geophysics and planetary physics mandate) provides an appropriate vehicle for the private co-investment component.
Commission a feasibility study (6 months, ~$150K): sensor performance modeling for the West African geological environment; range and endurance analysis for candidate basing locations; formal cost estimate.
"The prince asked the wise man: Tell me, is it possible for men to see the spirits and speak with them? ... I see the Earth's surface transformed into a lake of water. I see the Stars surging out of the water. I see a great number of men appear before us — some holding books and others holding writing tablets."
— The Tarikh al-Fattash (Chronicle of the Seeker), 16th century, Timbuktu
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