EXOLAUNCH Nova TestPod CubeSat Test System User Manual
- June 16, 2024
- EXOLAUNCH
Table of Contents
EXOLAUNCH Nova TestPod CubeSat Test System
Introduction
Purpose
This User Manual defines the interface requirements between a CubeSat and
Exolaunch Nova TestPod which is used for mechanical testing or for fit-check
purposes. The TestPod’s design is based on the Exolaunch EXOpod Nova CubeSat
Deployer and complies with the CubeSat Design Specification (CDS) Rev. 13
.
Figure 1:
Overview of the 4U, 8U and 16U EXOpod Nova TestPods
Quality Assurance
Quality assurance for the Exolaunch TestPod is ensured at every step of production. The entire production process fulfils the highest quality assurance requirements. The facilities which manufacture Exolaunch products such as the TestPod are certified with ISO 9001:2015 standard, which requires regular inspection of the manufacturing and assembly facilities and ensures a stable quality of the final product.
Applicability
This document is applicable until it is cancelled or replaced by another issue. This User Manual is a living document open for all corrections and amendments which occur in the lifetime of the TestPod.
Exolaunch Nova TestPod
Introduction
The Exolaunch Nova TestPod has been developed to facilitate mechanical testing
of CubeSats. It allows performing the full mechanical qualification of a
CubeSat inside the TestPod. The TestPod can be easily mounted on a shaker
table, with all mechanical interfaces being identical to the EXOpod Nova
deployer used during launch. This has an additional benefit of enabling the
TestPod to perform CubeSat fitchecks and also allowing a CubeSat to be shipped
safely in a TestPod if required. The system offers both a combination of the
highest reliability and user-friendliness.
This document describes the family of TestPods suitable for CubeSats from 1U
to 16U. Chapter 4 provides a detailed description of how to operate the
TestPod.
Components and Features
The main components of the 4U, 8U and 16U TestPods are shown in Figure 2. A detailed description is provided
- A clamping mechanism with adjustable set screws
- Access windows
- A rigid chassis with different mounting interfaces
- Slot adapters to accommodate any CubeSat size
- Integration table for easy and safe integration
Figure 2:
Components and features of the 3U TestPod. Components are the same no matter TestPod size
TestPod Properties and Interfaces
Physical Dimensions and Mass Properties
The outer dimensions of the three different sizes of TestPods including the
removable shaker adapter plate are shown in Figure 3 to Figure 5.
Figure 3:
Outer envelope of the 4U TestPod 
Figure 4:
Outer envelope of the 8U TestPod 
Figure 5:
Outer envelope of the 16U TestPod
The mass of the three different sizes of TestPods including the removable shaker adapter plate are shown in Table 1.
Table 1: Testpod mass with and without the shaker adapter plate
Unit| System mass [kg]| TestPod mass [kg]| Shaker adapter
plate mass [kg]
---|---|---|---
Nova TestPod 4U| 23.4| 13.4| 10
Nova TestPod 8U| 34.3| 20| 14.3
Nova TestPod 16U| 41| 26.7| 14.3
Mounting Interfaces
The 4U TestPod features two mounting hole patterns as shown in the Figures
below. All the mounting holes are through-holes for M10 screws with a nominal
tightening torque of 40.0 Nm. The mounting holes have an Ø 18 mm, 5 mm deep
counterbore for the screwhead. Note: A purchased TestPod can optionally be
manufactured with a different hole pattern.
Figure 6:
Mounting interfaces of the 4U TestPod 
Figure 7:
Mounting interfaces of the 8U and 16U TestPod
Lifting Points
Every TestPod has four threaded holes on the top side which can be used to
attach lifting handles. An example mounting is shown Figure 6. The screws are
tightened to 1.0 Nm. The handles are strong enough to carry the weight of a
fully loaded TestPod with significant margin for lifting any additional
masses, such as the adapter plate. For heavy lifts, the use of a crane is
strongly advised.
Figure 6:
Installed lifting handles with crossbars on the 16U TestPod
Slot Adapters
Using adapters, it is possible to fit smaller CubeSats inside a larger
TestPod. For example, a 1U CubeSat or 2U CubeSat using a 3U or 2U adapter
inside a 4U TestPod. These adapters are standard U sizes but can be customized
if the CubeSat is uniquely sized. The adapters are inserted into the TestPod
before the CubeSat is integrated.
Figure 9:
Examples of slot adapter sizes
Flight Representativeness
The CubeSat Design Specification does not outline requirements for flight representativeness of a TestPod or test fixture. The internal mechanical interface in the TestPod is identical to that of an EXOpod Nova deployer which allows the TestPod to be used for fitcheck purposes. The stiffness of the TestPod structure is significantly higher when compared to the EXOpod Nova deployer or any other typical deployment systems on the market. This, in combination with a different mounting interface, does have an impact on load transmission and levels experienced by the satellite. This difference is widely accepted by satellite manufacturers and launch providers in the scope of mechanical testing of CubeSats. Altering test levels to account for structural differences and dampening effects of the TestPod is not required. In some cases, when a more accurate representation of flight environments is deemed necessary, a test in a fully flight-like separation system may be preferable and can be performed on a case-by-case basis.
CubeSat Interfaces
Introduction
The Exolaunch TestPod has been developed to follow the CubeSat Design Specification (CDS). However, changes have been implemented which allow for integrating CubeSats that exceed some dimensions which are specified in the CDS, while still accommodating fully CDS-compliant CubeSats. CubeSats are constrained by three separate elements on the deployers: the rails, the deployment wagon, and the set screws located on the doors.
Maximum CubeSat Volume
CubeSats in Exolaunch Nova TestPods and deployers are allowed to exceed some
of the constraints in the CDS. For example, Exolaunch Nova TestPods and
deployers allow features to extend between 25-40 mm from the rails depending
on the size of the CubeSat. The maximum allowable dimensions for any CubeSat
size are outlined in Figure 7 and Figure 8 as well as Table 2. The teal-
colored areas (rails) mark the CubeSat interfaces with the TestPod; these
dimensions must be followed for the CubeSat to fit inside the TestPod. The
grey volume can be used in any desired way with the blue area representing the
so-called Tuna Can. The CDS states that Aluminum 7075, 6061, 5005 and/or 5052
shall be used for both the main CubeSat structure and the rails. However, the
rails must additionally be hard anodized. No other processes or materials
shall be used. Any deviation from the CDS, such as but not limited to the use
of different materials or surface finishes, i.e., other forms of anodizing or
a chromate conversion dual finish, may be incompatible with the Nova TestPod
or deployer. Any deviation from these requirements shall be approved by
Exolaunch in written form.
Figure 7:
Maximum allowable dimensions for CubeSats launched in an EXOpod Nova or Nova
TestPod.
Figure 8:
Maximum allowable tuna can dimensions for CubeSats launched in an EXOpod Nova or Nova TestPod
Table 2: Maximum CubeSat dimensions
Description| Units| Letter| 1U, 2U, 3U, 4U| 6U, 6UXL,
8U| 12U| 16U
---|---|---|---|---|---|---
CubeSat Rail Length (Z)
|
[±0.5 mm]| |
A
| 1U: 113.5
2U: 227.0
3U: 340.5
4U: 454.0
|
6U: 340.5
6UXL: 365.9
8U: 454.0
|
340.5
|
454.0
CubeSat Rail Width (X)| [±0.1 mm]| | B|
100.0
| 226.3|
226.3
CubeSat Rail Height (Y)| [±0.1 mm]| mm| C| 100.0
Max Space Between Rails (X)| | | D|
87.2
| 213.5|
213.5
Max Space Between Rails (Y)| | | E| 87.2
Max Protrusion from Rail (X)| | | F| | 39.5| |
| | | | 25.0| | 39.5
Max Protrusion from Rail (Y)| | | G| | 25.0| |
Number of Tuna Cans| –| –| 1| 2| 4| 4
Distance Between Tuna Cans| | mm| –| –| 126.3|
Maximum Mass| | kg| –| 8| 16| 32| 36
The 12U and 16U S1 Nova has an additional, fifth tuna can be located in the center between the four larger tuna cans, see Figure 8. The depth usable depth of this tuna can is 67 mm with a 62 mm diameter.
Access Windows
The access windows are located on the three outer faces of the TestPod
allowing for easy and quick access to the satellite after integration for
attachment of the accelerometers, visual inspection or for a quick functional
test using external ports during any point of the testing campaign. The exact
dimensions and location of the windows is shown in Figure 9. The nominal
torque for the access windows is 1 Nm.
Figure 9:
Dimensions of the TestPod access windows using a 16U TestPod as an example.
Dimensions are the same across different TestPod sizes
Rails and Clamping Mechanism
The CubeSat rails are the primary interface between the satellite and TestPod. The Nova TestPod uses the same clamping system as the EXOpod Nova. Exolaunch has developed a unique clamping system which is highly effective at constraining the satellite in the X and Y directions, thereby preventing it from shaking and rattling during transportation and launch. This clamping force is achieved by moving clamping surfaces on up to three guidance rails inwards towards the CubeSat. The mechanism engages as the door is closed, and the force increases linearly with a decreasing opening angle of the door. The total clamping force of the mechanism varies depending on the size of the slot as well as on the size of the CubeSat within the allowable tolerances. 4U, 8U and 16U slots have a clamping mechanism built into one, two and three rails respectively. As an example, a CubeSat on the lower end of the allowable size or 99.9 mm will experience a lower clamping force than a CubeSat closer to 100.1 mm. A changing clamping force has a notable impact on the transfer function and is one of the reasons why FE-modelling of coupled systems incl. CubeSat, CubeSat deployers and TestPods is not advised.
Deployment Wagon
The deployment wagon is situated between the back wall of the TestPod and the
CubeSat. In the Exolaunch Deployer it serves to keep the spring in the correct
orientation and ensures that the spring force is delivered correctly to the
CubeSat. In the TestPod, the deployment wagon does not carry a spring. It
serves as a mechanical interface and is fixed in place using four knurled
screws located on the back side of the TestPod. Nominal tightening torque for
the knurled screws 1.0 Nm. When these screws are removed, a set of pusher
tools can be used to facilitate the CubeSat’s de-integration. Both the
deployment wagon and the pusher tools are shown below in Figure 10
.
Figure 10:
- Left: Deployment Wagon for the 3U TestPod.
- Right: Pusher tools to facilitate de-integration of the CubeSat
Door with Set Screws
CubeSats are secured inside the slot by means of a clamping mechanism, which
applies a clamping force in the X and Y directions. CubeSats are further
constrained in the Z-direction by the combination of the Deployment Wagon and
the adjustable set screws located on the slot doors (see Figure 11). Once a
satellite is placed inside TestPod, the door is closed, and the set screws are
then tightened. This eliminates any gap created by loose tolerances, thus
prohibiting any movement in the deployment direction. Each set screw is
prevented from loosening by means of a fixation ring. When the fixation ring
is engaged, it is deformed such that both the set screw and the fixation ring
screw are both under increased running torque, thus retaining both fasteners
.
Figure 11:
Set Screw detailed view
Chassis
The TestPod is designed to be stiff and durable to maximize lifetime and reliability. This has the benefit of decoupling resonance frequencies from those of CubeSat. The removable flange allows easy mounting of the Nova TestPod on the shaker table and has up to two mounting hole patterns. For custom hole sizes and pitches, please talk to Exolaunch.
Integration Table
For easier integration into the TestPod, Exolaunch has developed an
Integration Table, see Figure 12. The Integration Table rails align with the
TestPod rails to sliding in the CubeSat quickly and safely. A detailed
description of the integration process can be requested from Exolaunch.
The Nova TestPod is further compatible with a similar integration table which
was developed for the EXOpod Nova CubeSat deployer, allowing for safe and
seamless integration from the TestPod into the Nova deployer, e.g. if the
TestPod was used for shipment.
Figure 12:
Integration Table attached to the TestPod
Transportation
For transportation purposes, the bottom plate that attaches the TestPod to the
shaker table can be removed. This improves the mobility of the TestPod and
simplifies transportation.
Figure 13:
The bottom plate removed for transportation purposes
Figure 14:
Outer envelope of the 4U TestPod without the bottom plate
Figure 15:
Outer envelope of the 8U TestPod without the bottom plate
Figure 16:
Outer envelope of the 16U TestPod without the bottom plate
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