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Balloon Launch
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Schedule
Oct/Nov 2007: NOVA 6 (CU)
09-12 Nov 2007: SEDS SpaceVision (MIT)
01 Feb 2008: Letter of intent deadline
approx. Apr 2008: Detailed report deadline
approx. Aug 2008: Abort test + motor test deadlines (New Mexico?)
approx. Oct 2008: SEDS Competition (New Mexico)
Avionics
ROCKET sensors:
- GPS (for retrieval) - COCOM issues
- barometric altimeter?
PLATFORM sensors:
- 2 axis gyro, to determine orientation relative to ground (i.e. ADXL320)
- camera (consider digital with onboard encoder so we can more easily store and transport the video, i.e. [1])
- GPS (for retrieval)
- barometric altimeter
PLATFORM comms:
- low-bandwidth uplink (ARM, FIRE, etc)
- high-bandwidth downlink (video, plus some GPS and altimeter data)
Example link budget:
- Receive power = (Transmit power) + (Antenna Gains) - (Free Space Loss)
- Free Space Loss (dB) = 20*log(4*pi*distance/wavelength)
- Noise floor = -174dBm (receiver at room temperature) + log10(bandwidth in Hz) + CNR(dB)
- so for zero gain antennas, 5MHz bandwidth, CNR=+9dB, we need -98dBm receive power
- Free Space Loss for 2.4GHz signal at 30km is about 130dB
- Therefore, (Transmit power) >= 32dBm = 1.6 Watts
- Goes up to 16 Watts when we're at 100km
Propulsion
Atmospheric Conditions
used the DesktopAero to tabulate key conditions at an altitude of 75000 ft, assuming the balloon speed to be 20, 50, 100 and 250 ft/sec respectively. Media:rocket data.xls