Enlarge / Orion looks inside people’s eyes spacecraft Simulator, which is used To prepare for docking to Gateway’s space station, use the Johnson Space Center’s System Engineering Simulator facility in Houston.

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NASA’s Wednesday launch is scheduled of The Artemis I mission will serve as the first integrated test of the agency’s SLS rocket and Orion spacecraft, which were in Development for 16 Years and are expected to Usher in a new era of space exploration. This uncrewed mission is also the second time that a time-triggered Ethernet network standard has been launched into space. The first was Orion’s. orbital test flight in 2014.

Time-triggered Ethernet (TTE(Is an example of A mixed-criticality network is capable of Traffic routing with different levels of Different fault tolerance requirements for different sets of components. of hardware. Until now, spacecraft One network was used to transmit mission-critical and safety-critical messages. A separate network was used for video conferencing. of less-critical traffic.

Illustration of how time-triggered Ethernet works.
Enlarge / Illustration of How time-triggered Ethernet works.


Engineers invented a better mousetrap. However, the mice defeat it.

Orion is Orion’s first spacecraft To rely on a TTE Network to route mixed-criticality traffic. NASA saysIt’s used for critical systems such as navigation and life support, file transfer that is crucial for delivery but not timing or non-critical tasks like crew videoconferencing. TTE—which will also be used in NASA’s Lunar Gateway space station and the ESA’s Ariane 6 launcher—is crucial for reducing the size, weight, cost, and power requirements of modern spacecraft.

Example of TTE data flow in a spacecraft.
Enlarge / Exemple of TTE Data flow in A spacecraft.


Safety-critical systems like engine control and steering often function only when network messages can be sent and received at very small intervals, such as 40 to 50 milliseconds. Delays or drops in messages can lead to catastrophic consequences. The other end of The criticality spectrum includes messages from scientific instruments. These messages often include in The form of They are available as commercial off-the shelf devices, and are provided by universities. NASA has not reviewed their safety. While it’s 100 percent compatible with the Ethernet standard, TTE Also, it can deliver messages that engineers would normally reserve for special-purpose networks.

To avoid messages less important interfering with the most critical, TTE These two benefits are unique and not available elsewhere in Regular Ethernet These are:

  • It is a time-triggered paradigm that ensures all devices are in sync and communicate messages on a set schedule. This can decrease latency up to hundreds of Microseconds to near zero jitter and jitter
  • Fault tolerance—TTE The network is replicated into multiple planes, and messages are sent across all planes simultaneously. The TTE Gateway for network has three planes.
gateway network overview


Tuesday will be a day for researchers published findings For the first time ever, break TTE’s isolation guarantees. PCspooF was the result. It is an attack that allows one non-critical device to connect to one plane to disrupt synchronization. TTE Devices on all planes An attack uses a vulnerability to exploit the vulnerability in The TTE protocol. Researchers from the University completed this work. of Michigan University of Pennsylvania and NASA’s Johnson Space Center.

“Our evaluation shows that successful attacks are possible in seconds and that each successful attack can cause TTE devices to lose synchronization for up to a second and drop tens of TT messages—both of which can result in the failure of critical systems like aircraft or automobiles,” Researchers wrote. “We also show that, in a simulated spaceflight mission, PCspooF causes uncontrolled maneuvers that threaten safety and mission success.”

Artemis Network Validation and Integration Laboratory (ANVIL) at NASA Johnson Space Center, where much of the research into PCspooF was conducted.
Enlarge / NASA Johnson Space Center, where more of Research into PCspooF was done.


PCspooF can be built onto as little as a 2.5 cm×2.5 cm area of A single-layer printed circuit board is possible. It requires very little power and bandwidth. This allows malicious devices to blend in. in All other devices that are connected to the network. NASA and other large stakeholders received the findings of the researchers in private. in TTE. A NASA representative sent an email to this address. “NASA teams are aware of the findings from research on TTE and have taken proactive measures to ensure potential risks to spacecraft are appropriately mitigated.”