National Aeronautics and Space Administration

Glenn Research Center

Secure Aircraft Systems for Information Flow (SASIF)

I. Summary

Shortly after Sept. 11, 2001, NASA and industry partners conducted demonstration flights downlinking aircraft cabin imagery, audio and “black box” data for ground-based monitoring of the aircraft environment for law enforcement officials.

Airport Network Illustration

The goal of the Secure Aircraft Systems for Information Flow (SASIF) was to secure the aircraft networks and communication links from intentional threats, enable surveillance of aircraft, and minimize protected airspace intrusions.

With the rapid increase of datalink and information technologies in the aircraft and the National Airspace System, the vulnerabilities of cyber threats had also increased. SASIF was intended to address these vulnerabilities by securing onboard networks, air/ground datalinks, and providing improved situational awareness of the onboard environment. These technologies would help protect air travelers and ensure that communication, navigation, and surveillance (CNS) systems on aircraft cannot be compromised.

Due to programmatic redirection, NASA phased out all aviation security-related research at the end of fiscal year 2005.


Research was conducted in two specific areas: secure airspace and communications systems and datalink and network hardening. The research objectives included developing protected airspace surveillance system concepts and technologies by looking at data fusion technology and working on gap-filler surveillance.

The datalink and network research focuses on detecting and protecting against network intrusion and hardening key network delivery systems including the air traffic control communications, aircraft data links and onboard networks.

The communications research looked at ways to remotely monitor onboard systems and the aircraft environment for information sharing and decision-making. The application- focused research addressed securing emergency communications, onboard information downlinks and uplinks and landing communications.

Technical Working Group

NASA had partnering relationships with TSA, DHS, FAA, FAM, NIST, and members of the aviation industry including Lockheed Martin and Volpe.


  • Develop protected airspace surveillance system concepts and technologies
  • Develop technologies for remote monitoring of onboard systems and the aircraft environment
  • Develop technologies to secure and harden aircraft datalinks and onboard networks

Technical Challenges

  • Security solutions within an acceptable level of overhead
  • Secure onboard wireless communications for Air Marshals and crew
  • Hardening of air/ground communications links without significant changes to existing infrastructure
  • Viable, affordable uplink of TFR info
  • Additional spectrum or datalink utilization to accommodate new security communications requirements
  • Secure authorization/key distribution across diverse NAS mobile/fixed and international/domestic networks


  • Partner with OGAs, industry and academia to leverage external research capabilities and enhance implementation
  • Conduct in-house research in unique areas
  • Develop necessary facilities to enable users and developers to evaluate technologies and identify improvements
  • Perform studies to assess technical impact of security technologies, trade-offs and cost benefits

Planned Deliverables

  • Protected Airspace Surveillance Technologies
  • Aviation Security Communications – Air marshal, bio/chem, biometric, secure landing encrypted datalink
  • Cabin, cockpit & aircraft systems surveillance
  • Intrusion-proof networks & datalinks
  • Secure key delivery systems

II. Accomplishments

A. Remote Monitoring of Aircraft Environment

In response to the events of September 11, NASA Glenn Research Center and its industry partners conducted demonstration flights in December 2001 and January 2002 downlinking aircraft cockpit/cabin imagery, audio and “black box” data for ground-based monitoring of the aircraft environment by law enforcement officials.

B. Initial Definition of Protected Area Surveillance Systems (PASS) Concepts

Completed final version of Protected Area Surveillance System (PASS) Concept of Operations Document (ConOps) which defined the operational plan for the PASS, and draft version of PASS Functional Requirements Document (FRD) describing the technical requirements to implement the PASS.

C. Initial Evaluation of Remote Aircraft Surveillance and Security Communications

Performed an initial evaluation of communications technologies demonstrating aircraft environment surveillance (data) by a ground mission operation center and the situational awareness and incident response coordination (voice & data) of airborne law enforcement officers within the aircraft and ground resources.

D. Aircraft Information Vulnerabilities Identification

A key challenge in securing aircraft information both onboard the aircraft as well the transmission of information onto and off of the aircraft is an identification of vulnerabilities this data may be subject to. SASIF’s Secure Aircraft Datalink and Networks (SADN) subproject commissioned a Security Policy report on Aircraft Data to investigate potential vulnerabilities.

E. UAT Datalink Enhancements for Improved Protected Airspace Surveillance and Datalink Hardening

NASA GRC and Sensis Corporation, through a cooperative agreement, demonstrated ADS-B pilot authentication and encryption security enhancements at GRC on June 28, 2005 for the UAT surveillance link.

III. Final Reports & References

  • Protected Airspace Surveillance System Concept of Operations (September 2004, not publicly available)
  • Protected Airspace Surveillance System Functional Requirements (September 2004, not publicly available)