In September 1999, NASA’s Mars Climate Orbiter missed its intended orbit and disintegrated due to atmospheric stresses. An investigation indicated that the Orbiter’s Device failure resulted from two pieces of software (one on earth and one on the orbiter) miscommunicating with different interface setups. One software was set to interpret data as imperial measurements (inches, yards, feet, etc.), and the other was set to interpret data in metric standards. As a result, the orbiter completely miscalculated the point of firing its thrusters, moved too close to the planet’s hostile atmosphere, and was lost.
NASA’s Root Cause Analysis
From root cause analysis, NASA identified these main issues:
- Lack of communication between project teams on units and measurements, plus
- NASA’s insufficient integration testing due to the unit oversight
Hindsight is a Wonderful Thing!
The total cost and loss of this project were estimated at a staggering $327 million! If only they had completed on small integration test, it would have saved them a fortune.
Thankfully, there was no loss of human life in this incident. But within this field and the field of medical devices, a small error like this can have catastrophic consequences.
Wider Validation & Verification Testing:
This is why it is vital to have robust integration testing as a wider part of validation which verifies that software modules within a medical device software are communicating correctly.
Integration Testing: What is it?
Integration testing is defined as a series of tests with the aim of either discovering internal errors in the interaction between software units of the medical device software or errors in the interaction between the medical device software and other software. Integration testing can also include discovering errors in the interaction with other hardware and medical devices.
Integration testing is very important to provide clinical evidence that medical device software demonstrates correct interoperability with hardware and other medical devices or IVDs.
What to Consider:
- A well-defined Integration test plan must be written up on what tests and/or test cases will be performed. This needs to include what the requirements are for the tests to pass and what resources or testers will be assigned for the testing.
- There are two main types of integration testing:
- The first is Incremental testing which is subdivided into a top-down or bottom-up approach.
Need help? LFH Regulatory has the expertise in SaMD to provide support to manufacturers on Integration and other testing elements for medical device software. Contact us today.
References
IEC ISO 62304-2015 Medical device software – Software life cycle processes
NASA Solare System Exploration https://solarsystem.nasa.gov/missions/mars-climate-orbiter/in-depth/#:~:text=Mars%20Climate%20Orbiter%20was%20designed%20to%20arrive%20at%20roughly%20the,23%2C%201999.
