VirtualSat® is Hammers’ dynamic simulation product. It is used to facilitate flight software development and build testing, spacecraft integration and test, operations team training, post-launch flight software sustaining engineering, and operations procedure checkout.

The Hammers VirtualSat® dynamic simulator has been used for several NASA missions supporting flight software development, spacecraft integration and test, and operations support for sustaining engineering across a multitude of projects and customers.

Most recently, our VirtualSat® was deployed on the NASA’s Magnetospheric MultiScale (MMS) mission, which is comprised of a constellation of four spacecraft. VirtualSat® hosts the spacecraft flight software, and simulates the dynamic environment so the flight software behaves as it will during the actual mission.Four instances of this combination run together on a single host computer to provide an MMS Training Simulator (MTS) of the entire constellation.

Since MTS hosts the actual flight software from each spacecraft, with dynamics, power and thermal models, the operations team is provided a simulation that is very similar to the actual orbiting spacecraft. Using Hammers’ Galaxy® ground system as the user interface platform, the system runs all four spacecraft in real time with command generation and telemetry display capability for each spacecraft.

VirtualSat® acts as a blank slate allowing software developers, testers, and control analysts unlimited options in configuring simulation environments to meet their specific needs. A spacecraft simulation can be built in minutes using pre-defined basic components and assigning characteristics such as mass properties and sensor & actuator configurations. VirtualSat® configuration is achieved through XML text files and the application is controlled via an Ethernet connection to a variety of GSE devices and can be integrated with Galaxy®. Data from VirtualSat® can also be sent to and displayed on these devices as CCSDS telemetry packets.

VirtualSat® has an API which matches NASA’s Core Flight Executive (cFE) interface. This simplifies integration of actual flight software (FSW) into the simulator. With the FSW integrated, simulations which can be configured on the fly to run in real time as well as slower/faster than real time provide a means to:

  • simplify and expedite operations training
  • debug/analyze flight software
  • checkout operations procedures

The VirtualSat® architecture allows individual components to be added and removed to increase/decrease the simulator’s fidelity as needed during the spacecraft development and maintenance lifecycle. The components can be reproduced to allow VirtualSat® to simulate multiple spacecraft in a formation flying configuration. With its support of interfaces to GSE equipment, the configurations and simulations can be script-controlled, supporting regression testing based on time and/or events. VirtualSat® has currently been interfaced with both the Galaxy® and ASIST spacecraft command and telemetry systems from NASA. Galaxy® provides a command interface to VirtualSat®, allowing a training conductor to inject an almost infinite variety of failures and other anomalies which exercise the FSW’s on-board failure detection and correction. These failures and their FSW responses can help flight operators learn to identify and respond to the anomalous conditions.