US military authorities learned a lesson from the war in Vietnam - managing information coming out of a war zone is almost as important as managing bombs going into it. As a result, we know pretty much exactly what the Pentagon wants us to know about the progress of the Afghan adventure, and no more.
By way of example: a key plank of US policy was that the war was being waged only against the extremist Taliban, not against the Afghan population. US war-planes would not drop their bombs on housing estates.
Just to make sure no one could argue the point, the Pentagon has bought commercial rights to all the imagery produced over Afghanistan by the Ikonos high-resolution satellite, which would have provided a foolproof way of verifying the facts.
The last image of Kabul now available on Space Imaging's Carterra database for public download was taken on 7 September.
The decision to use commercial rather than legal powers to prevent Ikonos imagery falling into the hands of journalists was taken to prevent US publication houses from using the First Amendment to the US Constitution, which guarantees freedom of speech. No such recourse exists to stop commercial arrangements, which have the same effect.
But if the public has only a limited understanding of what is happening in the country, it is interesting to contemplate what the US military itself knows. Apparently, the Russians created the best maps available during their own war in Afghanistan, covering the country at 1:50,000. The US mapping dates back to the 1950s and is at 1:100,000. The National Imagery and Mapping Agency, the military map makers, are using satellite imagery to update their maps, but it is doubtful that they can map the entire country before the end of winter.
Above: Zhawar Kili Al-Badr Camp in Afghanistan from a US KH-12 spy satellite. This image was used by US Secretary of Defense William Cohen and General Henry Shelton, the chairman of the Joint Chiefs of Staff, to brief reporters in the Pentagon on the US military strike on terrorist training camps in Afghanistan on 20 August 1998.
A primary source will be images from the French SPOT and Indian IRS optical satellites, and from the European ERS-2 and Canadian Radarsat radar satellites. These are being used extensively for general surveillance. In the case of the ERS-2 and Radarsat-1 satellites, the most obvious advantages are their all-weather and day/night capabilities.
Currently there are only two commercial high-resolution satellites available to the US - the US Ikonos-2 and the Israeli EROS-A1. The US QuickBird-2 and the Indian Technology Experimental Satellite were both launched in October, and will only become operational in 2002. All these satellites could be used for 1:1000 mapping if required.
EROS-A1 has only just come into service. Its main limitation is that it has no onboard facility for storing images, so a ground receiving station needs to be within sight of the satellite while the satellite is within sight of the target area. This geometry only occurs over the farthest western part of Afghanistan, when the satellite has a few minutes in contact with a downstation in Israel.
By contrast, Ikonos is likely to get heavy use. Afghan images can be acquired direct from a ground station operated by Space Imaging Middle East and located in the United Arab Emirates. Tape recorders are also available.
In view of the small number of fixed ground stations in the region, and the inevitable delays in sending imagery back to command stations, the possibility of using transportable receiving stations will be exercising US minds.
Almost certainly, consideration will have been give to the deployment of the Eagle Vision stations. These comprise a large van containing the receiving and processing equipment together with an antenna on a trailer. They can be transported in a C141 aircraft. Two new stations, Eagle Vision III and IV, were under construction and scheduled for December 2001 delivery.
The French military forces also have transportable stations, mainly for use with the French Helios military reconnaissance satellite. These units have been constructed by the Matra company, which has also played a substantial part in the construction of the Eagle Vision series.
The US military, of course, has its own assets in space. It is likely that considerable use is being made of the SAR imagers on the Lacrosse satellites operated by the National Reconnaissance Office. They can be operated in a variety of imaging modes. With the finest of these, the resulting images have a ground pixel size of one to two metres. At least two of these satellites were operational well before 11 September; a third was launched by the NRO on 17 August.
KH-12, or Corona, optical satellites have been placed in highly elliptical near-polar orbits with perigee values as low as 160 km and apogee values of 330 km. They resemble the Hubble Space Telescope but are pointed towards the Earth instead of into space. They are being used to produce very high resolution images of specific point targets.
The difficulty with any satellite is that it can only observe an area for 10 to 15 minutes each day and, in many cases, only once every few days.
By contrast, reconnaissance aircraft are much more flexible in terms of being able to take advantage of breaks in the cloud cover and being able to remain over an area of interest for a considerable period. This is certainly the case in Afghanistan, where the Taliban forces do not possess anti-aircraft weapons capable of reaching aircraft flying even at medium altitudes.
In particular, part of the US Air Force's substantial inventory of more than 30 U-2 aircraft seem certain to have been deployed to acquire imagery of Afghanistan.
The U-2 was developed in the 1950s, but modern variants, which can fly 27 km high, can be equipped with electro-optical (EO) and infrared (IR) imagers - the so-called Senior Year Electro-optical Reconnaissance System - as well as several different types of film camera. However, many U-2s are now fitted with the Advanced Synthetic Aperture Radar System (ASARS-2), which uses a new type of antenna that scans in azimuth electronically and features an enhanced moving target indicator capability. This provides an all-weather imaging capability.
The U-2 aircraft can also transmit its EO and IR image data in real time to a ground station, either through a direct radio link or via a communications satellite. According to press reports, the Royal Air Force has also sent a pair of its venerable Canberra PR9 high-altitude reconnaissance aircraft to the Persian Gulf area for possible deployment over Afghanistan.
What does seem certain is that the use of manned aircraft is being supplemented by the extensive deployment oof unmanned aerial vehicles designed specifically for reconnaissance and surveil- lance work. Many of the newer unmancyned craft feature ultra high altitude operation, extreme long range and an endurance that lies beyond they capabilities of human aircrew. Like the U-2, unmanned aircraft can transmit their images in real time to local ground stations.
Above: Imagery from an unmanned Predator aircraft. The TESAR (Tactical Endurance Synthetic Aperture Radar) is a strip-mapping SAR providing continuous 300 mm imagery. The focused imagery is formed on- board the Predator aircraft, then compressed and sent to the Predator Ground Control Station over a Ku-band data link. The imagery is reformed and displayed in a scrolling manner on the SAR workstation displays. The aircraft can also carry an optical camera.
One obvious candidate is the General Atomics Predator. This propeller-driven aircraft has an operational ceiling of about 10 km. It can fly 800 km to a target, loiter there for 24 hours and return.
Besides the Predator, another unmanned aircraft that is a candidate for use over Afghanistan is the Ryan Global Hawk, which can sit 25 km up for 24 hours. It can be fitted with EO/IR imagers and the Raytheon HISAR radar. So far, five of these Global Hawks have been delivered to the USAF; more are being built. Australia is to acquire several in 2005.
The prototype Predator unmanned aerial vehicle. This model does not carry the TESAR sensor.
Much of the information in this article came from the website of the Federation of American Scientists, www.fas.org, compiled by John Pike. Other pertinent material is from Gordon Petrie g.petrie@geog.gla.ac.uk at the Department of Geography and Topographic Science, University of Glasgow.
