Full Assembly Vibration Test Result

Test Procedures

1. For the z axis, subject the satellite to the vibration profile below.

   1. Take pictures before and after vibration.

   2. Save accelerometer data to computer.

   3. Set up satellite for next axis.

2. For the x axis, subject the satellite to the vibration profile below.

   1. Take pictures before and after vibration.

   2. Save accelerometer data to computer.

   3. Set up satellite for next axis.

3. For the y axis, subject the satellite to the vibration profile below.

   1. Take pictures before and after vibration.

   2. Save accelerometer data to computer.

4. Unpack the satellite from the deployer once it has been vibrated in each axis.

5. Inspect for damage to the deployment mechanisms and thermistors.

6. Inspect that the deployments have not deployed.

7. inspect for any loose external fasteners

8. Inspect for any visible cracks in the solar panels

9. Inspect for any other forms of breakage to the satellite

10. Should any of the inspections fail, the satellite must be torn down and reassembled with fresh components that address the failed inspection.

11. Conduct the reduced functional test if inspections are passed.

NanoRacks Vibration Testing Requirements

Iris was tested in a soft-stow configuration as outlined by NanoRacks in document NR-NRCSD-S0003 [1]. An overview of the requirements for the soft-stow configuration are provided below:

• "The CubeSat shall be capable of withstanding the random vibration environment for flight with appropriate safety margin as outlined in NR-NRCSD-S0003 Section 4.3.2.1" [1].

•  "Post-vibration test inspection records shall be made to verify that external components do not pose a risk of coming loose" [1].

•  "The soft-stow flight configuration shall be tested to the Maximum Expected Flight Level (MEFL) of +3db for a duration of 60 seconds in each axis using the soft-stow random vibration test profile given in NR-NRCSD-S0003 Table 4.3.2.1-1" [1].

•  "The CubeSat shall be integrated with the NRCSD or a mechanically equivalent test fixture wrapped in flight approved bubble wrap and foam provided by NanoRacks" [1].

Vibration Test Configurations

The following section details the soft-stow random vibration test profile that was used during the vibration tests, the intended deployer setup for the vibration tests, and photos of the packed deployer setup on the vibration table taken before and after vibration.

Intended Soft-Stow Test Profile

The soft-stow random vibration test profile is taken directly from NR-NRCSD-S0003 Table 4.3.2.1-1 [1].

Intended Configuration

The steps for setting up the soft-stow configuration are as follows:

1. Integrate CubeSat into the Test Pod

2. Move the Test Unit to the shaker table 

3. Check to make sure the technician has the appropriate profile loaded into the software

4. Determine first test axis (X, Y, or Z)

   • NOTE: if test pod or CubeSat cannot be rotated in between axis, a vertical expander head may be necessary to get the final axis

5. Place down Zotec Foam in the center of the table in the determined first axis

6. Place down the anti-static bubble wrap (1 or 2 layers)

7. Place the test unit on the bubble wrap

   • NOTE: Ensure the RBF face is facing the +Y axis. 

   • NOTE: because the set up is not inherently centered, ensure the unit is in the center of the table, or center of the bolt hole pattern on the slip table 

   • NOTE: If any accelerometers plan to be placed on the Test Unit, now is a good time to do that

8. Place anti-static bubble wrap on the top of the test unit

9. Place Zotec foam on the top of the bubble wrap 

10. Install eye bolts or hoist rings (depending on the size of the unit, 4 or 6 may be necessary)

    • NOTE: ensure the Test Unit is centered between the eye bolts

    • NOTE: test lab may have these items, or they may need to be provided. Check with lab on bolt hole sizes and availability of hardware prior to arrival for the test. Test Lab will also be able to identify torque specs for the eye bolts/ hoist rings

11. Use ratchet straps (2-3, depending on number of eye bolts) to restrain the Unit

12. Tighten rachet straps till two fingers have trouble slipping underneath the straps on the top of the unit

    • NOTE: the tighter the better. If you are concerned with amount of slack in the line, tighten further. 

13. Ensure unit is stable and all straps are tightened. Slack line from the straps should be restrained 

14. Run first Axis of vibration test

15. After test, ensure straps are still tight. Also ensure all fasteners and components of the test pods have not come apart

16. Breakdown the set up and repeat for next two axes. 

Pictures of Each Configuration

The x-axis test required the satellite to be rotated 90 degrees inside the deployer, therefore a brief adjustment of the satellite occurred between the x and y axis vibration tests. Additional foam was utilized where there were concerns about slippage between the deployer and the bottom layer of foam. Accelerometers were placed on the side of the deployer.

Z-Axis Configuration

X-Axis Configuration

Satellite Rotation

Y-Axis Configuration

Accelerometer Data per Axis

The test setup included one triaxial control accelerometer attached the vibration table and two triaxial monitor accelerometers attached to the sides of the mock deployer. Data for one of the monitor accelerometers was deemed unreliable for the z and y axis tests because it had come loose. The following section provides plots of the data measured by the control accelerometer for each test.

Control Acceleromater Response per Axis

Z-Axis Control Accelerometer Response

X-Axis Control Accelerometer Response

Y-Axis Control Accelerometer Response

Z-Axis Test Monitor Accelerometers Response

X-Axis Test Monitor Accelerometers Response

Y-Axis Test Monitor Accelerometers Response

Post-Test Inspection

After vibration testing was complete, Iris was taken out of the mock deployer and visually inspected for damage. This section ends with a brief discussion of the inspection activities that were performed.

Post-Test Photos

Post-Test Inspection Comments

The post-vibration test inspection of Iris found no problems. All fasteners remained secure, and all deployables remained stowed. No cracks were found on the solar cells, and no damage to the satellite was observed. Iris powers on and functions with no issues. The below table summarizes the inspection tasks performed.