Scientific Ballooning Brief history Electrodynamics over thunderstorms Balloon types How a balloon works Lift (forces)

January 2005 Flight From Antarctica Read about what it is like to do this experiment: Michael Kokorowski’s Antarctic Diary for the experiment: http://www.ess.washington.edu/~mkoko/

History First hot air balloon – French brothers – 500ft. for about 5 miles in 1783 War time usage Many ‘Firsts’ 1st to cross English Channel - 1785 1st to cross Atlantic – Double Eagle II - 1978 and Pacific – Double Eagle V - 1981 1st non-stop around the world – Bertrand Piccard from Switzerland and Brian Jones from Great Britain in 1999 (http://www.cameronballoons.co.uk/news/pr/rtw/news2.htm)

Other Records 1960 -- Altitude Record and Highest Parachute Jump: Air Force Captain Joe Kittinger jumps from a balloon at 102,800 feet on August 16th and sets a world high altitude parachute jump (where he breaks the sound barrier with his body) and freefall record that still stands today. 1961 -- Current Official Altitude Record Set: Commander Malcolm Ross and Lieutenant Commander Victor A. Prather of the U.S. Navy ascend to 113,739.9 feet in 'Lee Lewis Memorial,' a polyethylene balloon. They land in the Gulf of Mexico where, with his pressure suit filling with water, and unable to stay afloat, Prather drowns.

more 1988 -- Hot Air High Altitude Record: Per Lindstrand sets a solo world record of 65,000 feet for the greatest height ever reached by a hot air balloon. 1995 -- First Solo Transpacific Balloon Flight: February 14-17, Steve Fossett, another around-the-world contender with his Solo Challenger project, launches from Seoul, Korea and flies 4 long days to Mendham, Saskatchawan 2002 -- First Solo Round the World in a Hot Air Balloon: Steve Fosset, Started in Northam, Western Australia to Queensland, Australia. 13 days 12 hours 5 minutes (14 days 19 hours 50 minutes to landing), 20,482.26 statute miles (32,963 kilometers). This was Fossett’s 6th attempt at an around the world flight. Want More? See http://www.pbs.org/wgbh/nova/balloon/science/history.html

My Experiments: Stratospheric Electrodynamics over Thunderstorms Sprites and Lightning Measure electric field, magnetic field, X-rays Balloons in the stratosphere 10 to 15 hour flights with zero pressure balloons Coordinated ground-based measurements (more next lecture)

Sprite scenario balloon

Sprite movie

Balloon types zero pressure, super pressure, weather, blimp, tethered, cylinder, hot air, party Tethered Aerostat (blimp) NASA He air bladder semi-trailer

Hot Air Balloons Montgolfier - rigid tissue paper over frame Modern types are numerous – nylon, etc burners up to 15,000BTU or more people

ZeroPressure Balloons Highest and lightest Open at the bottom no pressure difference across flanks Sprite Balloon Test flight May 2002 Tillamook, OR Bob, Jeremy Michael

Zero Pressure Balloon When balloon gets to float altitude He has fully expanded and starts venting. Balloon stays at that altitude Duct to vent Helium no pressure difference across bottom and sides of balloon (only around the very top) payload

Super Pressure Balloon Longest Duration Sealed Bag Heavier (double layered – will not pop like rubber balloon) Spherical

Superpressure balloon flights 1992/3 Launched from New Zealand Record flights longest > 4 months

Forces on a Balloon Gravity (on the balloon and the gas) Pressure over the whole surface Buoyancy – You get ‘lift’ if the weight of helium+balloon is less than the weight of the air displaced So, how much does air weigh?

First lets talk about Density and pressure Density is the technical term for how much mass is in a volume. The more mass in a given volume, the higher the density density  = m/V= mass/volume Helium is less dense than air because each atom has less mass than atoms of Nitrogen and Oxygen

Atmospheric Pressure Think about an ocean of air above us pressing down Air pressure at sea level is 15 pounds/square inch. In other words, a column of air one inch square weighs about 15 pounds A 1 square meter column of air weighs 39x39x15 pounds or nearly 23,000 pounds

Lift Replace a volume of air with something that weighs less than that volume of air, BUT TAKES UP THE SAME VOLUME, and it will float Density of He is much less than the density of air Same number of atoms but each atom of He is lighter Upward Force = Lift = L Lift on the balloon is L= (weight of air displaced) – (weight of balloon+He+payload)