CubeSat Test Pod User s Guide Revision IV June, 2005

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Samson Stephens
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(SSDL) (805) 756-6479 Dept. of Aeronautics and Astronautics (805) 756-2376 fax (650) 723-8651 jpuigsua@calpoly.

1 Contacts: CubeSat Test Pod User s Guide Revision IV June, 2005 Cal Poly, San Luis Obispo Stanford University Prof. Jordi Puig-Suari Prof. Bob Twiggs, Director Aerospace Engineering Dept. Space Systems Development Lab. (SSDL) (805) Dept. of Aeronautics and Astronautics (805) fax (650) jpuigsua@calpoly.edu (650) fax btwiggs@leland.stanford.edu CubeSat Student Lead: Armen Toorian atoorian@calpoly.edu Official Website:

1.0 INTRODUCTION The Test Pod in Figure 1.1 is to be used by CubeSat developers as an environmental simulation of the P-Pod deployer shown in Figure 1.

2 1.0 INTRODUCTION The Test Pod in Figure 1.1 is to be used by CubeSat developers as an environmental simulation of the P-Pod deployer shown in Figure 1.2, this will allow validation of the structural integrity of CubeSats under launch loads. The Test Pod interior is designed to simulate the environment inside the P-Pod deployer. The Test Pod allows CubeSat developers to test their satellites to the environment inside the P-POD deployer rather than designing to the launch vehicle loads. Top Panel Spring Plungers Load Plate Figure 1.1 Test Pod

The developers are responsible for meeting the engineering specifications. 2.

3 Figure 1.2 P-POD CubeSat Deployer The Test Pod is not a fit check. CubeSats that do not meet the CubeSat Specifications (See Attached) may still fit in the Test Pod. The developers are responsible for meeting the engineering specifications. 2.0 DESCRIPTION The Test Pod interface control drawing is shown in Figure 2.1, this provides the necessary dimensions for adapting to your head plate. A Test Pod axis convention is also included in Figure 2.1, this will allow CubeSat developers to document and share results in a common format.

4 Figure 2.1 Test Pod Interface Control Drawing During the Z-Axis sine sweep test, the fundamental resonance was detected at roughly 600 Hz. Sine sweep tests repeatedly produced the fundamental frequencies shown below in Table 5.1. Fundamental Frequencies (Hz) X-AXIS Z-AXIS Test Pod Table 2.1 Natural Frequencies for 2 axes of the Test Pod

5 The intent is for CubeSat developers to share information learned during testing. Cal Poly will do its best to make all results available in future updates of this document. 3.0 ENVIRONMENTS 3.1 Sine Sweep The sine sweep test is recommended to include all available frequencies up to 2kHz. 3.2 Random A random vibration profile is not provided since a launch vehicle is not currently secured. CubeSat developers can obtain random vibration spectral densities to input to their shake table controller by referencing launch vehicle users guides. Some guides can be found on web sites such as: Future revisions of this document will include a worst-case spectral density based on launch vehicles that have been investigated by CubeSat.

6 4.0 PROCEDURES The following is a recommended procedure based on vibration tests performed at Cal Poly using a horizontal shake table. Individual circumstances will require the customer to amend these procedures. 1) Remove the top panel from the test pod assembly 2) Measure the thickness of the top plate and the load plate (see Figure 4.1) 3) Insert the load plate 4) Replace the top panel and start all top panel fasteners by hand 5) Lightly tighten the screws so that the panel is correctly aligned 6) Torque the screws until they are flush 7) Adjust spring plungers to the proper height: Height = Total Test Pod Height Satellite Height (at each rail) Pusher Plate Thickness Top Plate Thickness H = A B C D See Figure 4.1 for dimension labels.

7 Figure 4.1 Test Pod and Mass Model Dimensions Note that dimension B needs to be measured four times, once for each rail. The pitch of the spring plungers is 20 threads per inch. Therefore, to achieve the correct height, insert the spring plungers while keeping track of the number of full rotations. One rotation is a 20th of an inch. Starting from when the spring plungers grab the threads, use this information to calculate how many turns are required to reach the desired height. 8) Take precaution in mounting the Test Pod to the interface (head) plate as well as mounting the interface (head) plate to the test platform 9) Be sure to check all fasteners and data lines between tests to ensure a safe operating environment and accurate results 10) Mount the Test Pod to the interface (head) plate for testing 11) Orient Test Pod properly for testing of z-axis. Refer to Figure ) Check all fasteners and accelerometers are securely fastened 13) Input sine-sweep parameters for z-axis into controller and run 14) Inspect all fasteners and accelerometers for loosening or damage 15) Input random vibration parameters for z-axis into controller and run

8 16) Inspect all fasteners and accelerometers for loosening or damage 17) Confirm your requirements are met 18) Reorient Test Pod to test x-axis. Refer to Figure ) Input sine-sweep parameters for x-axis into controller and run 20) Inspect all fasteners and accelerometers for loosening or damage 21) Input random vibration parameters for x-axis into Controller and run 22) Inspect all fasteners and accelerometers for loosening or damage 23) Confirm requirements are met 24) Remove CubeSat and reorient in order to test the y-axis or mount the Test Pod accordingly and repeat steps 2-7

Test Pod User s Guide

Document Classification X Public Domain ITAR Controlled Internal Only Test Pod User s Guide Revision Date Author Change Log 6 11/6/2006 Jonathan Brown Moved to standard document format 1 of 6 1 Introduction