Japan's advances in superpressure ballooning - 4/24/2006

Japan, as well other countries as USA and France, are enganged in a sustained effort to develope a reliable technology for superpressure balloons. These balloons are basically a closed type of balloon wich flight at constant levels during a longest period than their cousins the classic "open stratospherics balloons". Several massive projects of meteorological prospection had made use of this kind of vehicles in the past of wich the NCAR's GHOST project and the french EOLE program are the most widely noted examples. The key of the interest of scientists in this tool is that it allows to make very precises measurements on the same atmospheric layer on long distances trajectories and also serve as a superb wind pattern tracer.

The only wakeness of the system is the very low payload weight capacity, merely beetween 5 and 30 kg. Nevertheless, Japan is pursuing from the middle 90's decade, to develope a new kind of superpressure balloon (sometimes called "The Pumpkin Balloon" taking account of his shape). Recently in the framework of that research a static test was held at the Fukushima prefecture townspeople gymnasium where a model balloon was inflated and tested. One of the test resulted in the burst of the balloon to examine if it withstands the high internal pressure. All test were succesfully acomplished, and the break down test executed showed that the balloon withstands as much as 2000 Pascal of pressure, 10 times the practical internal pressure in the stratosphere.

The project final aim is to develope a balloon capable of fliying during months carriying a increased weigth payload than available for superpressure balloons today. After the indoor test , the next step to be taken in May 2006 is to flight test the same balloon from the Sanriku Balloon Center in northern Japan.

BalloonWinds: a new project starting - 4/18/2006

Holloman AFB (USA).- The troposphere is the region of the atmosphere that is closest to the Earth's surface and where winds have a dominant effect on the entire weather system as well the most weather-related phenomena occur. A new project called Groundwinds funded mainly by the National Oceanic & Atmospheric Administration (NOAA) seeks to create a better and more accurate forecast model using widespread satellite coverage.

Althought the task appears not to be a very impressive one, the fact is that measuring tropospheric winds is crucial to the understanding of atmospheric and climate dynamics for weather forecasting. At present, wind data is collected mainly from a worldwide network of weather-balloon launches but there is a big gap in the information concerning the vast unpopulated ocean areas wich limit the accuracy of the forecast models.

Thus GroundWinds goal is to develop and demonstrate remote-sensing technologies that can be used to measure global tropospheric winds from orbiting satellites using Light Detection And Ranging (LIDAR) lasers, a technology that relies on the light scattering properties of the atmosphere. A laser is emitted into the atmosphere, and the light is scattered off of the molecules and aerosols (if present). This scattered light can be analyzed to directly determine various atmospheric properties including wind velocity, air density and temperature. Thus, if the initiative is succesful a worldwide coverage can be assured from satellites orbiting earth.

The project id divided in two segments GroundWinds devoted to made measurements from two ground stations -already functioning- located one in Hawaii and the other in New Hampshire and BalloonWinds the balloon-borne portion of the program created to validate in a more realistic basis the direct detection Doppler wind LIDAR technology.

The balloon segment is managed by the Michigan Aerospeace Corp. wich along with other companies as Raytheon, Fibertek and the New Hampshire University constructed the several subsystems and the gondola itself. It consists in the same kind of instrument used for the ground segment -an eye safe LIDAR laser and a telescope to see the scattered light- looking down from 30 km of height instead from the ground. A design emphasis was placed on rugged and compact packaging of the instrument system components due to the vibe and shock environment encountered during launch and landing of the balloon system. Also, several components are sealed and thermally stabilized to protect the equipment from the hostile quasi-spatial environment.

The flight plan calls for a total of 3 balloon launches beginning in the spring of 2006 with a duration of between 10 to 14 hours at float. The first flight will demonstrate the electrical, thermal, mechanical, and optical performance of the integrated instrument for nocturnal flight conditions. The second one will demonstrate the ability to operate during the daytime given the additional thermal load and the increased optical background. Then, instrument modifications based on experience from the initial flights will be made in the 6 months leading up to the final flight, which will experience both day and night conditions.

The balloon launches will be conducted from Holloman AFB by the Balloon Operations Group based in the Kirtland Air Force Base.

More information on the project is available at http://www.michiganaero.com/business_units/lidar/balloonwinds.shtml

This experience using laser beams fired from stratospheric balloons, is similar to another initiative called HAMPP (High Altitude Mobile Pointing Platform) that is already taking place on the same region in USA's southwestern states as we informed in our last december update.