Overview

On May 4, 2019 @Diane Reid has offered to fly all our electronic things on a high altitude weather balloon. To facilitate this we need accurate masses for ALL payloads utilizing this testing opportunity. The expected altitude is 80,000ft to 100,000 ft and the expected duration is 3.5 hours. This may require additional battery power or lower logging rates as well as environmental protection, primarily cold and wet environments.

Team!

We need an estimate for the full payload mass that we want to test, this includes avionics ASAP, we need to make sure that we are sizing the balloon and the parachutes correctly. Please see the information below and let’s put together everything that we need. Since we are going to test the payload on a weather balloon launch estimated 80,000 – 100,000 ft, we want to make sure that we are maximizing our results.

Below is useful resources with some related questions:

GPS

Can we verify what GPS system we are integrating in avionics. Some of the inexpensive EPS receiver chipsets give problems, let’s review.  A recommended GPS unit ("GPS5HA Module") is highly integrated and generally immune to ESD damage.

Cameras

The GoPro Hero4 with a battery backpack is generally recommended for weather balloons, I am aware that we intend on using a different camera on the rocket but let’s compare the specs. However, For the balloon better images and video than a GoPro, a CHDK-automated Canon point-and-shoot camera is recommended. Still waiting on avionics to give details on the parameters of our selected camera.  Details here: https://chdk.fandom.com/wiki/CHDK these cameras can be powered by AA batteries, because they'll accept the e^2 Lithium AAs.

Trackers

FindMeSpot tracker (only the 2nd generation trackers work reliably), and the cost of a T-size tank is not that expensive. Probably use this on the balloon.

Balloon structure and recovery:

Balloon we are using: 8245-H Hwoyee Weather Balloon, 1600 Grams Natural, and we are getting the regulator kit.  We’ll be using a pre-fabricated balloon and parachute w/ pre-fab rigging options, so we won’t be testing our recovery system here.  

Transmitters

Are we planning on adding APRS transmitters, if so I need all details.

For the high altitude balloon, most likely we’ll be using APRS Tx https://shop.bigredbee.com/collections/vhf-uhf-transmitters/products/2-meter-5-watt-aprs-transmitter (We can’t use the 900MHz system that they have because it was previously tested and discovered that the link won't close)

Recommended 900MHz radios for single balloons: http://store.rfdesign.com.au/rfd900p-modem-bundle/ (contains two modems, cables, and antennas).  RF Design also has an improved RFD900x module with a more capable processor, but don’t know how they fly.

Antennas

We won’t be chasing the rocket, but I’m giving you info that was passed onto me, for a compressive understanding.

Recommend 900MHz antennas for the payload: https://www.wa5vjb.com/products7.html  (we’ll need to work out connectors – (RFD900s use RPSMA connectors; normal SMAs won't work)

Recommended 900MHz antennas for the chase teams: https://www.wa5vjb.com/products2.html

Recommended 900MHz antennas for static installation (preferably on a tracking mount): https://www.rspsupply.com/p-105-pctel-bluewave-bmy890m5502n4-yagi-antenna-890-960-mhz.aspx

Power

Need to make sure that we are good with power/data.

For batteries, it is recommended to use 3S hobby-grade packs, and size the capacity based on what we are powering.  For tracking systems, run the batteries without protection – better to destroy a battery than have the tracker shut off.  For non-essential payloads or subsystems, use protected packs.  Virtually any supplier of hobby batteries will suffice - you're not going to be drawing enough current to cause careful cell matching to make any difference at all.

For DC-DC converters: https://www.dimensionengineering.com/products/de-sw050 (the link is for the 5V output converter, but they have a range of options, and also provide battery protection circuits).  These are high-efficiency switchmode regs which can be put in parallel, require no external components, and are electrically bulletproof.  

Please complete the table in detail below ASAP, listing details of components that will be used including all powering etc. All programming will need to be completed in 2-weeks.

Let me know if you have any questions @Diane Reid  

Payloads

Summary:

• All electrical senors to be tested on a high altitude weather balloon flight in 3-weeks. 
• List all payload components and masses due date: 4/8/18
• All software programming to hardware needs to be completed and flight ready by 4/22/19.
• Let me know if you have any questions @Diane Reid