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Day-in-the-Life Testing

Scope and Description

This topic page covers day-in-the-life (DITL) testing of fully integrated spacecraft. The goal of this testing is to verify that the complete system functions as expected in scenarios that mimic on-orbit operations. Because it includes all subsystems and mimics the specific time scales/dynamics of on-orbit operations, DITL testing is a valuable opportunity to detect (1) subsystem design or workmanship flaws that are difficult to detect at the subsystem-level and (2) integration flaws (e.g., in harnesses and interfaces) that cannot be detected prior to integration.

Resources under this topic area are primarily articles and whitepapers that include specific guidance and motivation for smallsat DITL testing. Note that DITL testing is essentially end-to-end functional testing of a fully integrated spacecraft; therefore, see the Integration and Test > Electronics Functional Testing topic page for more general guidance.

Best Practices and Lessons Learned

  • Include end-to-end testing of your communications system using your actual ground systems and verify correct execution of all commands.
  • Thermal vacuum (TVAC) testing is expensive, but DITL testing in vacuum enables detection of thermal issues that cannot be detected at ambient pressure due to a lack of convective cooling. Even limited DITL testing in TVAC is highly recommended and has identified potentially mission-ending flaws in other smallsats.
  • If possible, design deployables that can be reset without risking excessive fatigue or damage to the flight hardware. As pointed out in "Improving Mission Success of CubeSats" by C. Venturini et al., deployable failures have been the cause of a number of smallsat failures.
  • Use representative time-scales/dynamics as much as possible in DITL testing. This could significantly increase the duration of testing, but real-time scenarios will give you the best chance of identifying potential issues you could see on-orbit.


This doctoral thesis provides a comprehensive review of engineering project lifecycles from a wide range ... of organizations. It then presents a smallsat-specific mission lifecycle and demonstrates the application of that smallsat lifecycle to a university cubesat. Section 3 presents this smallsat lifecycle, including a detailed description of each phase and design review. The review in Section 2 is a valuable resource for understanding and comparing the various traditional systems engineering processes and associated design reviews.

This introductory document outlines the basic concepts and processes involved in developing cubesats. ... Chapter 6 Section 9 discusses typical testing procedures and reports necessary to verify cubesat-to-dispenser ICD requirements. Specifically, Section 6.9.1 details day-in-the-life testing of a cubesat to simulate the spacecraft's behavior while performing planned tasks.

Catherine Venturini et al.

This document discusses the importance of improving the methodology and process of developing cubesats ... to ensure mission success. Theme 5 of the paper details the importance of full system functional testing and how vital day-in-the-life testing is during the integration and test portion of the spacecraft development life-cycle.

Malte Gruber

This thesis described automated functional testing of the MIniature Student saTellite (MIST) cubesat ... and of various MIST electronic subsystems. This thesis is not comprehensive, as indicated by the significant "future work" that is required to complete implementation of the proposed solutions for automated functional testing. However, it provides valuable, detailed background and design information to inform the design and development of smallsat automated test procedures and low-cost test equipment.

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