The real question is, did SHIELD know it was for that specific result - the light speed engine?
Or was this secretly a Mar-Vell project, or, a Kree project?
What did SHIELD think it was about?
Was it simply about knowing more about the Tesseract?
Or...was it more about weaponizing it (as Dr. Zola did - in Captain America - The First Avenger)?
Did SHIELD know it was for that specific result - the light speed engine?
They were trying to investigate the properties of the Tesseract for it's power potential and to create weapons.
In the comics, Pegasus stands for "Potential Energy Group/Alternate Sources/United States,"
Mar-Vell was using her knowledge of the Tesseract for her own reasons
Captain Marvel plays off of the events established in The Avengers, showing that the Air Force also had a hand in SHIELD's work at Project Pegasus under Dr. Wendy Lawson, who was experimenting on the Tesseract as well for entirely different reasons. We find out that she was creating a Light-Speed drive for space travel.
