NASA IVHM Technology Experiment for X-37
The NASA X-37 IVHM Technology Experiment for X-37 will involve
running Integrated Vehicle Health Management (IVHM) software on-board
the X-37 spacecraft.
Objectives
- Demonstrate benefits of in-flight IVHM to the operation
of a Reusable Launch Vehicle
- Advance Technology Readiness Level of this IVHM
technology within a flight environment
- Operate IVHM software on the Vehicle Management Computer
- Unpiloted
- Reusable
- 27.5 feet long
- Mission
- launch from Space Shuttles cargo bay
- orbit Earth up to 21 days
- land autonomously on runway
- designed to allow future derivatives of the
design (such as the Air Force's Space
Maneuver Vehicle) to be launched atop an
expendable launch vehicles as well as from inside
the shuttle bay
- First flight in 2002
- Being built by Boeing for NASA Marshall Space Flight
Center
- Performs diagnosis using qualitative, Model-based
Reasoning
- Searches system-wide interactions to detect and isolate
failures.
- Reasons about complex system interactions within a real-time
monitoring and control loop, rather than requiring an
engineer to reason through all possible interactions and
hardwire the appropriate response to a pre-defined
set of failures.
- Updating and verifying the model is straightforward and
less labor intensive than the task of identifying changes
required in explicit procedural code.
- Streamlines the software development process and
maximizes code reusability across vehicles.
- Facilitates the generation of an explanation or
justification of the diagnosis, allowing the human
operator to decide whether the diagnosis is reasonable
before selecting or confirming the appropriate recovery
action.
- Was previously used in the Remote Agent Experiment
on board Deep Space 1
Overview of the hardware and software
The IVHM software will run as a task on the Vehicle Management
Computer (VMC). The Vehicle Management System (VMS) will be
another task running on the VMC (and written by Boeing). The VMS
will be responsible for telemetry and power management. The IVHM
task will communicate with the VMS task in order to obtain sensor
data and vehicle commands, and to send telemetry to the ground.
The VMC will use PowerPC microprocessors and will run the VxWorks
operating system. The IVHM software will be written in C++.
Scope of the Experiment
- Monitor and diagnose Electro-mechanical Actuators and
associated Electrical Power System components
- Real-time fault detection and isolation
- Diagnosis, not prognosis
- Shadow mode only (no reconfiguration commands)
- Generate advisory recommendations for ground ops
Challenges
- Limited resources (CPU, memory, telemetry bandwidth)
- Rigorous software safety standards
People
- From NASA's Computational
Sciences Division
- Mark
Schwabacher, Software Lead
- Scott Poll, X-37 Models & Monitors
- Jeremy Ou, integration, ground station, and monitors
- Lee Brownston, Livingstone support
- From NASA's Aerospace
Directorate
- Jeff Samuels, Technical Lead
- Mina Cappuccio, Task Manager
- Scott Christa, Software Integration and Test
- From Boeing Reusable Space Systems - Seal Beach
Publication
M. Schwabacher, J. Samuels, and L. Brownston. The NASA Integrated
Vehicle Health Management Technology Experiment for X-37.
SPIE AeroSense 2002.
Full paper (pdf, 150 KB)
This Web page maintained by Mark
Schwabacher.
Last updated March 13, 2002.