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L0w Cost Access to Near Space. I. Steve Smith, Jr. Southwest Research Institute sismith@swri.edu. Balloon history started on 4 June 1783 with the ascent of the first hot air aerostat followed, on 27 August of the same year, by the launching of the first gas balloon (hydrogen).
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L0w Cost Access to Near Space I. Steve Smith, Jr. Southwest Research Institute sismith@swri.edu
Balloon history started on 4 June 1783 with the ascent of the first hot air aerostat followed, on 27 August of the same year, by the launching of the first gas balloon (hydrogen). 1783 : In the Beginning ( Montgolfier Brothers)
Stratospheric balloons have… Flown >8000 lb. payloads Flown large payloads to 160 k-ft. Flown >700 days duration Stratospheric balloons cannot… Carry 8000 lb. To 160 k-ft for over 700 days Perform powered station-keeping (Stratospheric balloons are not airships)
Balloon Altitude Stability Differences Super-Pressure : No or minimal ballast requirement; Constant density float altitude Zero-Pressure Balloon (8% ballast mass/night or large altitude excursions)
Free Flyers Gas Montgolfiers (Hot Air) Powered Airships Types of Balloons
Types of Gas Balloons Zero-Pressure Hybrid Super - Pressure Stratospheric Airships
Zero–Pressure Balloons • “Open” system • Maintains ~ 0 differential pressure at the base of the balloon • Requires 8-10% ballast or dropping of mass each diurnal cycle to maintain altitude • Erego…limited durations of 3-5 days in mid-latitudes except in polar regions • Typical altitude excursion of 2-10 k-ft day to night • Large payload capacity (see following chart) • Sizes range from a few thousand ft3 to ~60 million cubic feet3 (mcf) Most common balloon in use today • RACOON is an unballasted version • No ballast • Altitude excursions ; 30-50 k-ft • Durations dependant of atmospheric lapse rates or gas loss (20-60 days)
Spherical Lobed: “Pumkin” Tetroon Super-Pressure Balloons • “Closed” system---pressure vessel • Maintains differential pressure within balloon • Requires no ballast • Requires high strength materials • Durations weeks or months days anywhere globally (small SP flown fro several hundred days) • Typical altitude excursions of 1-2 k-ft • Payloads usually a few hundred pounds. ULDB/Pumpkin developing for 2000 lbs • Sizes range from a few thousand ft3 to ~26 mcf
Typical Hot Air Montgolfier Infrarouge & Solar Montgolfiers Solar Montgolfiers Types of Montgolfiers……Hot Air Balloons • “Open” system • Lift derived from heated gas • Requires heat source to maintain altitude (propane, RTGs, etc) • Some make use of thermal radiation sources (ie infrared or solar) • Durations limited by availability of heat source
Montgolfier Infra-Rouge MIR vehicle (Montgolfiere Infra-Rouge) is a hot air balloon of 36000 to 45000 m3, with natural shape, only heated by radiative fluxes from the sun by daytime and upwelling infrared fluxes during the night.
Stratospheric Airships • Stratospheric Airships are powered, streamlined “balloons” designed to station-keep • Relatively small payloads (10s-100s lbs) • Altitudes usually 60,000 – 75,000 ft • Durations : days to weeks • Still under intensive development by DoD • Only 2 have ever flown successfully under power (HiSentinel20); 20 lb sensor capacity • Future is HAA of several thousand pounds 2010 Nov 2007 Nov 2005 4/99 – 11/01 – 5/03 HiSentinel
HiSentinel Size Comparisons 2010 Nov 2007 Nov 2005 4/99 – 11/01 – 5/03
Dynamic Static Dynamic How Are They Launched?By……….. Land Sea Air
Middle Top Bottom Where are payloads mounted?
Environmental : Extreme • Worse than orbiting spacecraft • Very long eclipse times (12 hrs possibly) • Very localized thermal IR extremes (thunder storms) • Primary thermal driver is radiative (convection negligible) • Atmosphere changes with time of year and latitude • Tropopause temperatures are “generally” colder in summer and higher in altitude and are warmer and lower in winter • Temperatures are “generally” warmer towards the poles • Temperature of -90C can be seen
Latitudinal Wind Profiles Jaska 2005 Environmental : Winds • Winds vary with latitude, altitude and time of year • NH winds blow westerly in the summer and easterly in the winter • Turn-around occurs in spring and fall when stratospheric winds reverse.
120,000feet 60,000 feet 847 Miles 80,000feet 692 Miles 520 Miles How much can we see? How much can we see? Stratospheric Fields of View Footprint Diameter to the Horizon
Prepared by O. Bruegman & G. Cashin/ITMI 165 130 k-ft 130 Olympus ENABLED SCIENCE Atmospheric Background Interferes 95 Altitude (Feet x 1000) Atmospheric Transmittence Problems Atmospheric Interference & Water Vapor Absorption of IR. Atmospheric 60 Transmittence Problems 35 0 Gamma Ray X Ray U V Optical I R Wavelength What Can We See?
Titan Imagination: Let it run wild Venus
Thank-You I. Steve Smith, Jr. Southwest Research Institute sismith@swri.edu 210-522-3587