Overview

Our manufacturing team is responsible for developing a model of our satellite in software and producing all of our custom parts – notably our chassis.

For cost accessibility, we are manufacturing as many components as possible in house, including our chassis, which is milled out of a single block of Al 6061.

For knowledge accessibility, we are thoroughly documenting the design and design process, through the series of CAD files and designs we have created. In addition, we are documenting our manufacturing techniques and tips, in hopes that mistakes we make can be prevented in the future.

CAD (Computer Aided Design)

Every part in EquiSat is modeled in CAD and combined together to create a full assembly of the entire satellite, down to every screw and resistor. This allows us to accurately keep track of our mass and COG. Additionally, we can use this assembly to generate wire lengths for Avionics, produce production files for our CNC router, and run accurate thermal models. Our software of choice is SolidWorks.

In accordance with the mission goals of EQUiSat, the files for the full assembly will be published on our resources page once the design is finalized.

CircuitWorks

To assist in routing wires through our satellite and to determine the length of the wires before we physically put them in the satellite, we routed wires in CAD in our full satellite assembly.

To do this, we used an add-in of SolidWorks, called CircuitWorks. To begin, we put all of EAGLE files of the PCB boards into CircuitWorks, where they were converted to assemblies containing the various components. These sub-assemblies were then put into the larger assembly, and the wires were added using a routing feature of CircuitWorks.

Manufacturing

Our team has access to all of the tools in Brown’s machine shop. In keeping with our mission goals, we are building all of our parts using only equipment found in a typical university machine shop.

Equipment:
  • 3 axis CNC mill
  • Lathe
  • Taps
Materials:
  • Al 6061 for metal parts (chassis, radio posts, etc…)
  • Delrin (battery block)
  • Machinable Wax to perfect machining technique

 

G-Code will be published once perfected.

Chassis

The chassis is the backbone of the satellite. It is milled by a CNC mill from a solid block of aluminum. This approach is significantly cheaper than other approaches, and allows us to easily customize our design. The rails are designed in accordance to strict NASA specifications, so three can be stacked in a P-POD. The rest of the chassis was designed specifically to fit and properly secure our payload.

Design Notes

  • Integrated Fasteners for mounting of PCBs and battery block
  • External mounting holes for solar and flash panel attachment
  • All major features are 8.5mm thick

Manufacturing Notes

  • Milled from single piece of 6061 Aluminum Stock
  • Used basic 3 axis CNC mill
  • Structure and tolerance to conform to CubeSat specifications
  • Mill from all six sides to save time

Programming Notes

  • Drew chassis in SolidWorks
  • Copied file to AutoDesk Fusion 360
  • Created toolpaths and generated G-Code

(Full Instructions will be available soon.)

Kill Switches

Two kill switches are required to be in a CubeSat; one to keep the satellite turned off while undergoing integration on the ground, and the other to turn off electronics during the launch and while in the P-POD to avoid interference between multiple systems.

RBF Pin

The Remove Before Flight (RBF) pin is a pin that is inserted into EquiSat, and is removed once in the P-POD. This pin, while inserted, must disconnect all electronics from the power source, to avoid any accidental satellite component deployments or adverse interference between the three CubeSats.

Deployment Switch

The deployment switch is engaged once the satellite is placed in the P-POD. When cubesats are placed in a P-POD, springs are placed inline between each satellite and the P-POD wall. These springs compress and keep the RBF switch engaged. On deployment the P-POD is opened, which allows all of the springs to expand. This turns on all of the satellites and ejects them all out of the P-POd with spacing between each. When the satellites turn on, they will begin a 45-minute timer. After 45 minutes, the radio antennae can deploy, and our satellite will begin operations.

Design Spreadsheet

Below is a list of all of the major components of the satellite. These components are the largest, and drive the design of our chassis and attachments. As our satellite continues to develop, this list may change.

Expand Table

Subsystem

Part Name

Description

QPA

Power Side Panel “Side” Solar Panel board 3
Power Top Panel “Top” Solar Panel board 2
Power Flash Batteries A pack of LiFePO4 batteries – used only for driving LEDs 4 (2s2p)
Power Electronics Batteries A pack of Li-Ion batteries – used for all other electronics, including the radio 2 (2p)
Electronics Control Board Main Avionics Control Board 1
Electronics ATMEL Microcontroller Satellite CPU 4
Flash LED Panel LED Panel 1
Flash Driver Board Board containing circuitry to power the LEDs 1
Flash Luminus CHM-27-50 LED High power 5000K color LED 4
Attitude Control Permanent Magnet This magnet will sit perpendicular to the flash side of the satellite 1
Attitude Control Hysteresis Rods These magnets will provide transient detumbling of the satellite 2
Radio Radio Transmitter An XDL Micro transmitter will provide health data and location via the 435MHz band 1
Radio Antenna Superalloy dipole antenna 1
Radio Deployment Posts Machined posts will be used to wrap and subsequently deploy the antenna in orbit 3
Manufacturing Monoblock The solid Al 6061 chassis is the body of EquiSat and fastening points for all components 1
Manufacturing Battery Block A block that clamps all 6 of our batteries together around the Battery Board PCB 1