The 1985-1986 South Pole balloon campaign

This paper will provide an overview of the University of Houston-University Park/University of Maryland-College Park balloon program that was carried out at Amundsen-Scott Station, South Pole, Antarctica, during the 1985-1986 austral summer. The paper will emphasize objectives, instrumentation and operations. The quality of the data and periods of special interest will be discussed while final conclusions will be left necessarily to a later time. The primary experimental tools used in this program were unmanned stratospheric balloon payloads. The balloons used were helium-filled and had a volume of 5100m^3. The payloads had a mass of 24.5kg, giving a nominal float altitude of 32km. The payloads were instrumented with three-axis, doubleprobe field detectors and X-ray scintillation counters. Secondary instrumentation onboard measured the stratospheric conductivity, the ambient temperature and pressure. Three of the payloads also included tone-ranging transceivers. Equally essential to the program are the ground-based data from the South Pole Station Cusp Lab, the newly developed conjugate observatory, the Goose Bay HF radar, the Sφndrestrφm radar, and satellite data from the DE spacecraft. In the month starting on 16 December 1985 and ending 16 January 1986,8 successful balloon flights were conducted, ranging in duration from 6 to 103h 30min. A total of 468h 30min of data were obtained under a wide range of magnetic conditions. Periods of particular interest include 19 December 1985,28 December 1985,30 December 1985,2-3 January 1986,and 7-8 January 1986

Some Thoughts on Satisfying Spacecraft Passivation Requirements

Most spacecraft have at least one pressurized vessel on board. In addition to a hole, it is possible that a pressure vessel may experience catastrophic failure (i.e. rupture) as a result of a hypervelocity impact. If a tank rupture were to occur on-orbit following a micrometeoroid or orbital debris particle impact, for example, not only could it lead to loss of life, but it would also generate a tremendous amount of debris that could compromise future space assets working in similar orbits. As a result, NASA and other space faring nations have put in place spacecraft design requirements to prevent additional sizable debris from being created in the event of pressure vessel rupture or catastrophic failure. In general, these requirements state that a spacecraft’s stored energy devices are to be passivated at the end of a spacecraft’s mission or useful life. Programs whose spacecraft designs are not be able to comply with some aspects of those requirements employ an alternative, so-called “soft passivation”, option. This paper provides a summary of a project performed with the intent of providing some possible guidelines and considerations that can be used by satellite programs to help satisfy passivation requirements using a “soft passivation” approach, that is, when not able to perform complete hard passivation