Satellite Description and Operations

Satellite Description

The YODA satellite is an 18" tall, 13-5/16" diameter cylinder which was designed to house several subsystems as well as payloads. It was built to fit within Ye Olde Launcher Can and survive subsequent launch and shock tests. The satellite was required to have two subsystems to measure the sun angle and the temperature.

The sun sensor determines the angle of incoming light in a 120 degree arc with an accuracy of 15 degrees. A flashlight is used as the light source, and when it is aimed at the sun sensor, a voltage is measured at the ground station corresponding to the illuminated sensor bin.

The temperature sensor can measure whether it is hot, normal or cold and this information will be sent to the ground station which will show the appropriate voltage.

The YODA satellite has three payloads which may be operated by the user:

A radio-controlled motorized head
Blinking LEDs and
Beeping whistle sounds

Satellite Cost

Subsystem	Cost ($)
Power	10.02
Thermal Sensor	1.94
Sun Sensor	4.74
Command & Data Handing	9.93
Communications	9.61
Payload	34.34
TOTAL	$70.58

Satellite Operations

YODA is turned on by flipping the metallic power switch near the bottom. This will provide power to the sun sensor, temperature sensor, CPU and communications. The motorized head must be turned on separately using the black switch several inches above the satellite power switch.

The user can toggle between reading sun sensor data or temperature data by pressing the read button on the ground station. It is sometimes necessary to aim the LED on the ground station at the detector on the satellite. This toggle also controls the blinking LEDs and beeping sounds on YODA and causes them to activate momentarily.

	Measurement	Period (msec)	Resistance at Ground Station
Sun Sensor	Bin 1	2	150.6
	2	2.2	129.3
	3	2.6	109
	4	3.4	86.6
	5	3.8	81.7
	6	4.2	74.1
	7	4.4	70.2
	8	4.9	63.8
Temp. Sensor	Hot	4.8	61.5
	Normal	5.4	55.7
	Cold	6.6

The motorized head is actuated by a simple radio control. Pulling back on the trigger moves the head up while pushing forward on the trigger moves the head down. Twisting the round knob on the side of the remote control turns the head side-to-side.

The YODA satellite is a very modular design that is conducive to on-sight repairs and quick assembly. The structure consists of three plates which are attached with velcro to an outer shell which provides support and stability. All subsystems are mounted to these plates. Markings on the plates align with those on the outer shell to assure proper assembly and prevent possible catastrophic failure of the payload.

The launch adapter consists of several peices of foam strategically placed to isolate vibration and shock. Two foam pads are placed in the base of the Ye Olde Launcher can to accommodate the launch pegs. A third layer of foam is attached directly to the bottom of the satellite using spray adhesive and this is joined to the other layers of foam by spraying more adhesive to the foam in the can and gently lowering the satellite. Two 4" strips of foam encircle the upper portion of the satellite and are secured in place using duct tape. This prevents severe lateral displacements which could potentially lead to failure.

YODA