Ground Sphere CubeSat Ground Station » Ground Sphere Test Transmitter

h1. Ground Sphere Test Transmitter - Initial Questions v0.1

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h2. Project Background Questions

h3. BQ1. Why are we making this?

*BA1*. _There are two reasons for building this test transmitter.  First, it helps to have an initial "smoke test" for the *Ground Sphere Ground Station*. What this means is that when someone assembles a copy of the Ground Sphere hardware, they should be able to easily test it to make sure that nothing major is wrong.  Second, there are very few other 915 MHz satellites in orbit that are useful for testing the *Ground Sphere Ground Station* at the time of this project's inception.  Having a test apparatus like this allows us to simulate satellite reception through terrestrial tests and possibly even High Altitude Balloon launches._

h3. BQ2. Who is this for?

*BA2.* _The *Ground Sphere Ground Station* is for "SkyCube backers":http://www.kickstarter.com/projects/880837561/skycube-the-first-satellite-launched-by-you/backers, students, teachers, scouting troops, space enthusiasts, and anyone who wishes to directly participate in the SkyCube mission. Therefore, this test transmitter is intended for the same audience._

h3. BQ3. How will this be used?

*BA3*. _Ground Sphere Ground Station operators will use the test transmitter to:_

* _Do an initial test to make sure that the *Ground Sphere* hardware is capable of receiving 915 MHz transmissions in a laboratory environment._

* _Do an initial test to ensure that the *Ground Sphere* hardware is capable of receiving 915 MHz transmissions at a receive signal strength equivalent to a satellite on orbit._

h3. BQ4. Who's going to build this?

*BA4.*  _The designs will be open so that anyone, without necessarily a technical education in amateur radio or satellite operations, would be able to build and operate a *Ground Sphere Test Transmitter*._

h2. Technical Requirement Questions

h3. TQ1a. What features does it need to have (now)?

*TA1a.* _The test transmitter needs to:_

* _Transmit radio signals at 915 MHz_

* _Be mobile so that the terrestrial tests can be done by adding distance between the transmitter and *Ground Sphere* receiver_

* _Be easy to assemble from kit components and only require simple tools (screw drivers, pliers, wrenches, etc) for assembly_

* _Have low shipping costs for the packaged kit_

* _All software required to operate the test transmitter must run on a Windows PC_

* _The test transmitter must connect to the test transmitter programming computer through a commonly available port (for example: USB)_

* _The test transmitter hardware should minimize the opportunity for mechanical failures (from things such as broken connectors or a lack of strain relief)_

h3. TQ1b. What features does it need to have (later)?

*TA1b.* _In the future, the project (or related projects) may need to:_

* _All software required to operate the ground station must run on Windows, OS X, and Linux_

* _Transmit BPSK-modulated, unencrypted AX.25 data packets sent at 9600 baud_

h3. TQ2. What are the legacy requirements?

*TA2.* _To maintain compatibility with other projects, the system should:_

* _N/A_

h2. Project Requirement Questions

h3. PQ1. How many do we want to make?

*PA1.* _As an open source hardware kit, the long term objective is to promote and sell as many ground station kits to as large of an audience (schools, scouting troupes, makerspaces, space enthusiasts, etc) as possible.  However, the narrow focus on supporting SkyCube operations with the *Ground Sphere* may limit the number of kits which will be sold for this specific ground station, especially since the SkyCube is going to be on orbit for a very limited period of time.  The sales lifetime of this specific kit (and in turn the number of kits we will want to sell) will depend on how many other satellites there are to observe in the same frequency range as the SkyCube.  Note, there are approximately 2700 backers of the SkyCube KickStarter, of which Southern Stars is committed to delivering ground stations to between 20 and 30 backers.  This gives a minimum number of ground stations to be built of 30 +/- 5, which would cover the minimum backers and a handful for Mach 30's use._

_The timing of the project may also limit the scale of the initial run Mach 30 can produce.  This decision will be revisited later in the development process (after the second prototype) to allow the development team to address the manufacturing logistics._

h3. PQ2. What is the budget?

*PA2.* _The materials cost should be kept under $75 to limit the retail cost of any kit versions._

h3. PQ3. What is the timeline?

*PA3.* _The timeline for this project is dictated by the SkyCube launch and deployment timeline.  SkyCube is currently scheduled was launched in January 2014, with deployment from the ISS in Q1 or Q2 of 2014.  Southern Stars has stated they would be comfortable with a February 2014 delivery date for the kits._

h3. PQ4. What waste products will be produced by the manufacture and/or operation of this?

*PA4.* _TBD_