When finding the best Parachute for the project, one must understand what affects the use of a parachute. Wind speed and atmospheric density are the two most important components that have an impact on a parachute.
When traveling at high speeds, basic parachutes typically burst. In order to slow descent before deployment of main parachutes drogues are used. Drogues are smaller, but more powerful parachutes capable of enduring high speeds.
One can use the terminal-velocity formula to determine at which altitude and speed the different parachutes should be deployed. The equation is shown below. The variables stand for: the mass of the falling object (m), acceleration due to gravity (g), drag coefficient (Cd), density of the air based on altitude (ρ), and projected area of the object (A).
Typical parachute openings occur at the altitudes between 2,500 and 5,500 feet, but the lowest opening altitude is at 2,000 feet. In order to open the parachute automatically, an AAD or automatic activation device is used. AADs are small computers that monitor the altitude and activate the parachute. The price varies between 1,000 and 1,600 dollars.
Where to order equipment
Highaltitudescience is a company that provides all necessary products for personal space missions. They have an Eagle Flight computer that records date from multiple sensors. This is includes GPS, pressure, and external temperature. They also sell a flight manual that helps select best conditions such as jet stream direction and strength. Highaltitudescience also helps file a Notice to Airmen (NOTAM) by calling the local Flight Service Station and providing them with basic information about your launch.
Maximum altitude
The average altitude a helium balloon reaches is about 20 to 30 miles up. Recently, Michel Fournier was planning to do a parachute jump from the edge of space. His balloon would have gone well past 30 miles because his team started with the balloon almost entirely empty. If there is just a tiny bit of helium at the start, the balloon will have plenty of time to expand before reaching the top of the atmosphere. The highest recorded air balloon flight traveled to an altitude of 173,000 feet (53 km).
A radiosonde is a small, expendable instrument package that is suspended 25 meters (about 80 feet) or more below a large balloon inflated with hydrogen or helium gas. They are important to research because they are relatively similar to our space probe. As the radiosonde rises at about 300 meters/minute (about 1,000 feet/minute), sensors on the radiosonde measure profiles of pressure, temperature, and relative humidity. NOAA National Weather Service (NWS) uses radiosondes to take upper air observations. A radiosonde can ascend to over 35 km (about 115,000 feet) and drift more than 300 km (about 180 miles) from the release point. They are exposed to temperatures as cold as -90oC (-130oF) and an air pressure less than 1 percent of what is found on the Earth's surface. If the radiosonde enters a strong jet stream the device can travel at speeds exceeding 400 km/hr (250 mph). When released, the balloon is about 1.5 meters (about 5 feet) in diameter and gradually expands as it rises. The balloon bursts when it reaches a diameter of 6 to 8 meters (20 to 25 feet) in diameter. A small, orange colored parachute slows the descent of the radiosonde, minimizing the danger to lives and property.
Brainstorming
The image above represents my brainstorming process. During the research stage, I copied down ideas that my findings inspired me. My brainstorming included all possibilities of designs whether or not they are viable. For example, I was reading about the limited altitude of weather balloon flights, so I drew some images of "thrusters" to help maximize altitude.
Works Cited
Bengston, Kristen. "A DIY Space Capsule Requires DIY Parachutes." Wired.com. Conde Nast
Digital, 19 Dec. 0011. Web. 06 Sept. 2013.
"FAQ - High Altitude Weather Balloon." FAQ High Altitude Weather Balloon. N.p., n.d. Web. 07
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"How Skydiving Works." HowStuffWorks. N.p., n.d. Web. 07 Sept. 2013.
"HowStuffWorks Blogs." The Blogs at HowStuffWorks RSS. N.p., n.d. Web. 07 Sept. 2013.
"The Naked Scientists." How High Could a Helium Balloon Go? -. N.p., n.d. Web. 07 Sept. 2013.
" On How to Start Your Own Space Program. WelcomeWelcome to High Altitude Science."
Highaltitudescience. N.p., n.d. Web. 07 Sept. 2013.
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