The requirements for the Air Launched Balloon System (ALBS) development program and the highlights of that program, prior to the flight test phase, are presented. The rationale behind an ambitious ALBS parachute subsystem test flight series, using C-130 aircraft, at the National Parachute Test Range is given, along with the initial system configuration chosen for that series. The test-demonstrated inadequacy of the 32-ft drogue chute is documented. The successes achieved subsequently in flights with a 28-ft drogue chute (in combination with the 42-ft main chute) are described, both for tests employing a dummy balloon and for later tests in which a real balloon was used. Attempts at partial balloon inflation at the NPTR are discussed. The unsolved parachute coning problem is also described, along with tests aimed at its solution. Planning and preflight preparations for the January 1978 balloon drop test over the White Sands Missile Range are covered in considerable detail. The abortive launch of that flight is related and an analysis of the reasons for the flight failure is presented. Five (5) appendices are included with supporting calculations.

This publication contains the Keynote Address and twenty-nine papers presented at the Tenth AFGL Scientific Balloon Symposium, 21-23 August 1978, at Portsmouth, NH. The five sessions were entitled: Balloon Technology - Progress and Problems; Manned Flights; Stratospheric Measurements; Airship Design Concepts; and Methods and Models.

This report covers the theoretical advantages and practical ramifications of a proposed new technique for compensating for the daily loss of lift (gamma) experienced by long-duration high-altitude scientific balloon flights. This technique, 'Gas Replenishment', would transfer stored helium from an onboard dewar to the balloon, to replace gas lost due to temperature excursions. It would be a direct substitute for systems presently in use which drop ballast, that is, reduce system gross weight, to compensate for loss of lift. (With gas replenishment, lift is restored directly, with only a small change in system gross weight. A short summary of zero-pressure balloon flight theory is given at the start, to lead into the explanation of conventional ballast practices and computations. The ballast equations are then modified to apply to the gas replenishment technique. Calculations for typical constant-gamma flights are summarized for each method of loss compensation and the clear superiority of gas replenishment is demonstrated in the areas of gross system weight of launch, usable payload weight and anticipated flight duration. Basic equations are then developed for a more complicated model of the gas replenishment system in which the value of gamma varies from day to day. Computations using these formulas are summarized in tabular form. The final section of the report is given over to the design problems associated with the type of dewar and heat exchange equipment needed to implement the gas replenishment concept. (Author).

This document serves as the third revision of the USAF Parachute Handbook which was first published in 1951. The data and information represent the current state of the art relative to recovery system design and development. The initial chapters describe representative recovery applications, components, subsystems, material, manufacture and testing. The final chapters provide empirical data and analytical methods useful for predicting performance and presenting a definitive design of selected components into a reliable recovery system.