ScanPyramids. The ScanPyramids mission is an Egyptian-International project designed and led by Cairo University and the French HIP Institute (Heritage Innovation Preservation). This project aims at scanning Old Kingdom Egyptian Pyramids (Khufu, Khafre, the Bent and the Red) to detect the presence of unknown internal voids and structures.

The project, launched in October 2015, combines several non-invasive and non-destructive techniques which may help to get a better understanding of their structure and their construction processes and techniques. The team was using Infrared thermography, muon tomography, 3D simulation and reconstruction techniques.

ScanPyramids is an interdisciplinary project mixing art, science and technology. On November 2, 2017, the ScanPyramids team announced, through a publication in Nature, its third discovery in the Great Pyramid, a "plane-sized" previously unknown void named the "ScanPyramids Big Void".

Discoveries

2016 
On October 15, 2016, ScanPyramids confirmed their first unknown void discoveries thanks to muon tomography in the Great Pyramid. A previously unknown cavity was confirmed on the North-Eastern Edge, roughly at  high with similar void volume characteristics as a known "cave" located at  on the same edge.

A second void was discovered behind the chevrons area of Khufu's North Face above the Descending Corridor (referred to as "SP-NFC" in papers). This area was investigated after thermal anomalies observation that led the team to position muon emulsion plates in the Descending Corridor. This void was further investigated during 2017 to provide more information about its shape, size, and exact position.

2017 

In 2017 more muon-sensitive emulsion plates were positioned in the descending corridor and in Al-Mamun's tunnel. The void behind the chevrons could be confirmed through different points of view and its characteristics refined. Named "ScanPyramids North-Face Corridor" (SP-NFC), this void is located between  from the Great Pyramid's ground level, between  from the North Face. It could be horizontal or sloping upwards and it has a corridor-like shape.

ScanPyramids Big Void (SP-BV) 

On November 2, 2017, the ScanPyramids team published its third discovery in Nature, which was named "ScanPyramids Big Void", or "SP-BV" for short. It describes a newly discovered huge void in a circumscribed area above the Grand Gallery. It is estimated to have a length of at least  and a similar cross-section as the Grand Gallery. The ScanPyramids Big Void has been observed by three teams of physicists from different points of view (2 points of view in the Queen's Chamber and from outside in front of the North Face).
 
Three scientific institutions specializing in particle physics have worked independently and each one used a different and complementary muography technique:

 Nagoya University, Japan: Nuclear emulsion plates in the Queen's Chamber under the leadership of Professor Morishima Kunihiro
 High Energy Accelerator Research Organization (KEK), Japan: Scintillator hodoscope in the Queen's Chamber
 Alternative Energies and Atomic Energy Commission (CEA), France: Muon telescopes with gas detectors positioned outside in front of the Great Pyramid's North Face.

Like the work done on the "ScanPyramids North Face Corridor", more muography observations, from new viewpoints, need to be conducted in order to better determine the Big Void's shape, so that functional inferences can be drawn.
As long the exact layout and function of the void is still unknown, the scientists have been cautious about using architectural nomenclature.

North Facing Corridor (SP-NFC) 
In March 2023, the team published its finding of the North Facing Corridor (NFC) behind the original entrance; the void is called "SP-NFC" (ScanPyramids - North Face Corridor) in the paper.

Reactions

Egyptologists 
On November 2, 2017, the Egyptologist Zahi Hawass told the New York Times: "They found nothing...This paper offers nothing to Egyptology. Zero."

On November 3, 2017, Egypt's Ministry of Tourism and Antiquities said in a statement, "The existence of several void spaces inside the pyramid is not a new thing. Egyptologists and scholars knew about it several years ago," adding, "the ministry sees that the ScanPyramid team should not have rushed  to publish their findings in media at that stage of their research because it requires more research and it is too early to say that there was a new discovery."

On November 4, Khaled al-Anany, Egyptian Minister of Antiquities said, during a press conference, that the void space found inside the Great Pyramid of Khufu by the ScanPyramids project is a new revelation that brought the world's attention to Egypt. He added "What was discovered is new and larger than the known cavities, and we'll continue in our scientific steps".

Other Egyptologists have welcomed the discovery. Yukinori Kawae told National Geographic "This is definitely the discovery of the century...There have been many hypotheses about the pyramid, but no one even imagined that such a big void is located above the Grand Gallery."

Peter der Manuelian, from Harvard University, said that "This is an exciting new discovery, and potentially a major contribution to our knowledge about the Great Pyramid."

Physicists 
Lee Thompson, an expert in particle physics at the University of Sheffield (UK) told Science: "The scientists have "seen" the void using three different muon detectors in three independent experiments, which makes their finding very robust." Christopher Morris, physicist at Los Alamos National Laboratory called the findings "pretty amazing". Jerry Anderson who worked on Khafre's Pyramid and was a member of the team of Luis Walter Alvarez, the first scientist to use muography inside a pyramid in 1965, said to Los Angeles Times, with a laugh: "I am very excited and very pleased,...I wish we had worked in the Great Pyramid, now that I look back on it".

International media 
This discovery has been featured in many international media as one of the top discoveries of the year 2017 (NBC News, Euronews, Physics World, Science News, Global News, Gizmodo, Business Insider, Altmetric, Egypt Today, NBC, MSN News, Le Monde, CTV, The Franklin Institute, Radio Canada, Sciences et Avenir, RTÉ, PBS, Yahoo, La Vanguardia, France Info).

References 

Egyptology
Particle physics