FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1982
1982 - 2745.PDF
Top Subsurface features in the eastern Sahara are revealed in this syn- thei'c aperture radar view. Above The same part of the desert, as seen by Landsat SAR glimpses desert past A synthetic aperture radar (SAR), flown on the second Shuttle flight, has revealed subsurface patterns in the eastern Sahara for the first time. Radar signals are typi cally reflected from the Earth's surface, but dry sand is fairly transparent and allowed penetration to a depth of l-5m. In this instance the signals reflected off bedrock and gravel layers below the sand, revealing ancient river val leys, geologic structure, and signs of Stone Age oc cupation. Some features are as wide as the Nile Valley of today, and could be up to 50 million years old. They are likely to explain oasis distri bution in the desert, and could be immensely useful to archaeologists. The Selina "sheet" in this part of the Sahara is almost completely flat, with a surface of coarse sand and fine peb bles. Nasa's results were pro duced by L-band trans missions at 230mm wave length. The SAR, called SIR A, illuminated the ground at FLIGHT International, 18 December 1982 an angle of 50° from the verti cal, covering 50km-wide swaths on the ground. Resolu tion was 40m and peak power lkW. SIR A was similar to the SAR flown on Seasat, which differed in having an inci dence angle of 20°. Nasa spent about $6-4 million on SIR A. It plans to fly the SAR again on STS 17 in August 1984, as part of the Osta 3 experiment group. Nasa is modifying the SAR for this mission, so that obser vations will be possible at in cidence angles of 15-60°—via a tilting antenna. It calls the new version SIR B. BAe recruits space engineers British Aerospace Dynamics is to take on 200 more people at its Stevenage factory, and a further 100 at Bristol. The company is looking for stress, integration, electronics, and microwave engineers, and ex pects recruitment to continue until the end of next year. Most of the new staff will work on Europe's direct- broadcast satellite, L-Sat, or Britain's Skynet IV military communications craft. Others will contribute to enhanced ECS, and to scientific projects such as Giotto. N0AA juggles weather craft National Oceanic and Atmo spheric Administration (NOAA) is repositioning weather satellites, following the failure of the fourth geo stationary operational envi ronmental satellite (Goes 4). This craft, which covers the western USA from a geosta tionary longitude of 135°W, is believed to have suffered an electrical failure on November 25. Manufacturer Hughes Air craft is still attempting a fix, but the chances of success seem small. NOAA currently has six weather satellites in geosta tionary orbit. It has decided to re-activate Goes 1, turned off several years ago, as a tem porary fill-in for the failed satellite. Goes 1 was at a longitude of 116 • 2°W, but NOAA initiated a 0-5°/day drift westward on December 8. The satellite will be stopped at a longitude of either 129° W or 135°W, depending on what the Weather Service decides. Goes 1 is only equipped to make daytime observations, however, unlike the more sophisticated Goes 4. In the meantime, NOAA is managing to cover the west with poor-quality views from Goes 2 (107°W) and Goes 3 (135 • 5° W), plus ground-based observations. Oblique images from Goes 5 (85°W) are of limited value. Another craft, SMS 2 (75°W) is similarly un helpful. The situation will improve in summer next year, follow ing the launch of Goes F (6) in April. SPACEFLIGHT Inmarsat eyes new-generation satellites Inmarsat is to request indus try bids for its next satellite generation in August 1983. The first of these craft, de signed to continue maritime links, will be launched in 1988. Inmarsat expects to buy three craft initially, but will specify options to buy more, depending on need. A total of $500 million is likely to be spent on the second generation, which should last until 1995. There is a chance that Inmarsat will extend its service to include relay of distress calls, and to communications links with aircraft. • Inmarsat is extending its lease of the Pacific Ocean Marisat by six months, until mid-1984. • Negotiations have begun with the European Space Agency on the cost of a replacement for Marecs B, lost on the last Ariane launch. • The organisation is to study technical, financial, and oper ational aspects of satellites in polar orbit. Such craft would plug gaps in the current geo stationary orbit network, by providing maritime coverage in the polar regions. Spaceshots... Ferranti has won a £ll mil lion order to supply gyro scopes for the attitude-control system in Europe's L-Sat direct-broadcast satellite. US expendable launches in 1983 Launch Date January January February March April May June June July July August August August September October Fourth quarter December December Satellite Iras Intelsat V-F NOAAE RCAF Goes F San Marco D/L Galaxy A T83 1 Tel star 3 A Navy 21 RCAG AF 1 NOAAD Galaxy 6 Nato III D Navy 22 AF2 IntelsatVA A Purpose Infrared astronomy Communications Weather Communications Weather — Communications — Communications — Communications — Weather Weather Communications — — Communications Launcher Delta 3910 Atlas-Centaur Atlas F Delta 3924 Delta 3914 Scout Delta 3920 Scout Delta 3920 Scout Delta 3924 Scout Atlas E Delta 3920 Delta 3914 Scout Scout Atlas-Centaur Range Vandenberg AFB Cape Canaveral Vandenberg AFB Cape Canaveral Cape Canaveral San Marco platform Cape Canaveral Vandenberg AFB Cape Canaveral Vandenberg AFB Cape Canaveral Wallops Island Vandenberg AFB Cape Canaveral Cape Canaveral Vandenberg AFB Wallops Island Cape Canaveral 1749
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
