Real world of artificial satellites
by Balraj Singh
THE launch of Sputnik-1 by Russia on October 4, 1957 marked the beginning of satellite technology. It opened doors for the study of our planet from a high vantage.

Countering volcanic ash in flight
by D.K. Arora
WITH so many active and dormant volcanoes to overfly every day, airlines the world over have felt the need for information about volcanic ask encounters for both safety and financial security, for such mishaps can prove costly to an aircraft.

Is life 50 million years old?
by Tim Radford
A CAMBRIDGE scientist and two Chinese colleagues have pushed the history of all vertebrates back by at least 50 million years. They have identified fossils of two previously unknown species of fish in rocks laid down in what is now south China, 530 million years ago.

New information technology
by B.R. Sood
OVER the past 30 years computers and computer-based information technology have made inroads into everyday life and at places have changed lifestyles dramatically.

Real world of artificial satellites
by Balraj Singh

THE launch of Sputnik-1 by Russia on October 4, 1957 marked the beginning of satellite technology. It opened doors for the study of our planet from a high vantage. Today, the term ‘remote sensing’ immediately reminds us of the picture of cloud pattern shown after news bulletins. This, however, is only a very limited, though important application of artificial satellites. This technology has played an important role in various spheres of life — from business to entertainment, from resource planning to rural education and so on. Besides, being the most complex technology, it has led to vast developments in various related fields like rocketry, sensing, imaging, communication, data processing, robotics, material science, manufacturing process etc.

As shown in figure, various orbital configurations are possible, suiting different requirements. An orbit strictly in the equatorial plane is called an equatorial orbit. If height of a satellite in this plane is increased to 35,850 km, it becomes ‘geostationary’ — ideal for communication, as it remains at a ‘fixed’ point, as seen from the earth. Reducing this height and tilting the orbit results in a tropical orbit, which is capable of covering the tropical regions for remote sensing. A polar satellite, on the other hand, circles roughly parallel to the longitudes and covers entire globe. As it completes one revolution, the earth also rotates a bit, showing new areas during next revolution. The polar orbit can also be adjusted so that the satellite always passes over a particular region at the same local time. This eliminates the brightness and contrast differences due to different angles of illumination and the resulting orbit is called ‘polar sun-synchronous orbit’.

If a satellite has to continuously observe a particular object, e.g. the sun, or the galactic centre etc., it is often put into a highly elliptical orbit, so that the earth does not obscure its view for a major fraction. As geostationary satellites in equatorial plane do not cover polar regions, countries like Russia make use of communication satellites in highly elliptical orbits with apogee over their land.

As the atmosphere is highly transparent to visible (@10-7m) and microwave (>10m) radiation (see chart), most on-board instruments operate in this region. Passive sensing is done through measurement of natural radiation emitted or reflected from the surface or atmosphere, while active sensing involves the receiving back of radar pulses transmitted by the satellite.

Since the first launch, the on-board equipment has evolved from a simple radio beeper to most complex devices. While transponders constitute the major part of equipment on a communication satellite, a remote-sensing satellite is equipped with a number of sensing devices along with a communication link. One class of instruments, known as ‘sounders’, measures a particular parameter, such as water vapour, as a function of height. The satellite altimeter data is used for mapping the topography. Radiometers measure the amount of water vapour present in the path of a radar pulse. Surface temperature is mapped by measuring microwave emissions. As microwaves can penetrate dry soil, subsurface sounding is possible in desert using radar. Radar is also extremely useful in mapping ice in dark polar regions, as microwaves are emitted differently by water and ice, even at same temperature. The same technique is also employed for mapping wet and dry soils. A near infrared sensor performs mapping of ores and minerals. A color scanner maps the coastal water color and the presence of vegetation. Ultraviolent scanners detect hydrogen and helium while X-ray and gamma ray detectors provide information regarding the availability of radioactive materials on the moon etc! Besides these, satellites are also used for global positioning systems as well as military applications.

Presently, 500 operational satellites are circling our planet; and these constitute only 6 per cent of the total. The day is not far when we shall be having a whole constellation of satellites, feeding enormous data into a network of super-fast computers, allowing things like — one month advance weather forecast, and so on.

Countering volcanic ash in flight
by D.K. Arora

WITH so many active and dormant volcanoes to overfly every day, airlines the world over have felt the need for information about volcanic ask encounters for both safety and financial security, for such mishaps can prove costly to an aircraft. In fact, the airlines have set up a system for reporting volcanic activity. Qantas Airways leads in this respect as its international route structure is unique in the 95 per cent of its departures from Australia pass over areas of known volcanic activity.The need for a reporting structure for flight operations in all areas having volcanic activity was highlighted by the well documented, potentially catastrophic British Airways’ encounter with volcanic ash from Mount Gulangung in Indonesia in 1982. While there was no loss of life, the considerable damage to the aircraft accounted for several million dollars’ loss in revenue and repairs.Thus, both safety and cost must be continuously reviewed from an operational perspective when flying close to known volcanic activity. This particular encounter triggered the development of the ICAO International Airways Volcano Watch (IAVW) as well as a Qantas reporting structure — focusing on the Asia/Pacific region — to supplement it.

Of the hundreds of volcanoes active in the Asia/Pacific area, Qantas currently keeps and active file on 69 of them, stretching from Indonesia through the Philippines and New Guinea to the South American coast. Past experience has shown that, normally, the airline’s first indication of volcanic activity in the Asia/Pacific area comes from pilot reports or local staff.

Dispatch reaction to this information must be immediate and according to the following priorities: First, identify aircraft in or approaching the affected area and pass them all available information, including re-routing options, if required. Second, simultaneously identify aircraft about to depart that may be affected and, if required, develop new flight plans that avoid the affected area. Third, liaise with the Darwin Volcanic Ash Advisory Centre (VAAC), one of the nine designated VAACs of the ICAO and commence an investigation through the airline’s own sources; and lastly, ensure that all aircrew are kept informed of the latest developments.

Timely advice is critical for the safety of the aircraft, passengers and crew, and while this is of foremost consideration, such information is also critical in preventing serious damage to the aeroplane. Complete avoidance of volcanic ash is the only procedure that guarantees flight safety, according to Qantas representative on an Australia-based committee concerned with volcanic ask avoidance.

Consequently, effective lines of communication from ground observers, pilots and meteorologists to dispatchers and air traffic controllers are essential. Information sought at this time includes accurate determination of the plume height, ash positioning and forecast projections, winds aloft in the region, and additional pilot reports. Once open links have been established with the Darwin VAAC, the local authorities and other sources, the next step is to build diversionary routes and to continuously review information and provide comprehensive briefings for crews and possibly other airlines.

It is extremely important for the local authorities involved to continuously review NOTAMs and SIGMETs concerning volcanic occurrences and retract them as soon as the situation stabilises, allowing airlines to resume use of optimum routes at the earliest possibility.

The three most recent volcanic eruptions which have had a sigificant impact on Qantas were Mount Pinatubo, June-October 1991; Mt Rabaul, September 1994; and Mount Rinjani, June 1994 to March 1995. In the case of Mt Rabaul and also Mount Rinjani, the first notification of significant volcanic activity received by Qantas was through pilot reports.

During the initial eruptions, Qantas suffered several inflight diversions, considerable re-routing and cancelled services. The extra track miles necessary to avoid encounters with volcanic ash were quite extensive. In the case of the Mount Pinatubo, flights between Australia, Hong Kong and Taipei were extended by 200 nautical miles (NM). For the Mount Rinjani, an additional 160 NM were flown between Sydney or Melbourne and Singapore and an additional 82 NM were necessary on the Darwin-Denpasat route. The Mount Rabaul eruption forced aircraft between Australia and Japan to fly an extra 350 NM.

The additional operating costs incurred by the extra miles in the aforesaid examples totalled Australian $ 6.9 million (Australian) or about $ 3.9 million at the current exchange rate. This figure does not take into account the cost of missed passenger connections or any of the commercial variables, including infrastructure costs.

To improve reporting of volcanic activity and enhance safety for all airlines within the region, a reporting structure was established by the Association of Asia Pacific Airlines (AAPA) in 1995. This system evolved from meetings of an ad hoc volcanic ash group chaired by Qantas.

The scheme requires all participating airlines to report volcanic activity directly to Qantas flight dispatch and, of course, to the air traffic control (ATC).

This can be achieved through aircraft communications addressing and reporting system (ACARS), high frequency single sideband (SSB) radio, satellite phone, and ATC. It can calso be accomplished by having the crew convey the information to company personnel who then forward the data to Qantas. Upon receipt of this information, the Qantas dispatch immediately prepares and sends a volcanic activity sighting advice. This information in the sighting advice includes originator of the sighting; volcano’s name and the International Association of Volcanology and Chemistry of the Earth Interior (IAVCEI) identification number; the coordinates, spot wind, temperature and time of sighting and direction of the plume and affected airways. The latter point is especially important when the ash plume is above FL 200.

This urgent message is forwarded within minutes to all airlines based in the region plus additional European and US carriers which have requested it. Other recipients are the Darwin VAAC, ATC and ICAO. All airlines operating flights in the area are encouraged to report any volcano activity, irrespective of the degree of eruption, using the ICAO special air-report format. Whenever Qantas is given such information, it processes the data and fowards it to individual airlines for their own analysis.

Qantas has always adopted a conservative approach to the reported volcanic activity. It is estimated the carrier spends up to $ 2.2 million annually on flight diversions made while information about volcanic eruptions is checked to determine whether optimum routes can be declared safe.

In summary, the airlines’ expectations for more efficient volcanic ash avoidance is based on a steady improvement in the efficacy of the IAVW, including better modelling of ash plumes by the VAACs to assist avoidance planning; a more timely communication of eruptions; advanced warning from authorities of possible eruptions; improved satellite data following accurate plotting of plume drift; and increased cooperation among airlines to ensure a useful exchange of information.

It is in everyone’s best interest that mutual cooperation be extended, with all airlines and agencies contributing to safety and prevention of a catastrophe caused by an aircraft flying through volcanic ash. — CNF

Is life 50 million years old?
by Tim Radford

A CAMBRIDGE scientist and two Chinese colleagues have pushed the history of all vertebrates back by at least 50 million years. They have identified fossils of two previously unknown species of fish in rocks laid down in what is now south China, 530 million years ago.

This is the first evidence of vertebrates in what is known as “the Cambrian explosion”. Until about 600 million years ago, life on earth was composed mainly of microbes and other very simple organisms. Shortly afterwards, there was as strange flowering of creatures, many now known only as rare fossils with names such as Anomalocaris and Hallucogenia.

The new vertebrates looked, in life, like fish “fairly stubby, but with quite a powerful body with muscles on it, so they were swimming quite actively” says Simon Conway Morris of Cambridge University, an expert on the period, and the author of a paperback called the Crucible Of Creation.

“The world they were living in was in some senses quite similar to ours, and the basic ecology was already established. In terms of the details, it was very, very different. These fish are fish, but they don’t have any jaws, so they are basically the same as the living lamprey. They probably swept up small particles of food.

“The rest of the world was brimming with arthropods of various sorts. Anomalocaris and Hallucogenia would have been strutting round on the seabed, and there would have been worms on the sea floor,” he says. The fossils were found by Degan Shu of Northwest University, Xi’an, in Yunnan province, who has reported the matter with Conway Morris in Nature. “He sent me some photographs and swore me to secrecy. I went out to China and spent two weeks working on the fossils,” he says.

The age of the creatures can be identified with some confidence: they were found along with species of trilobite which have themselves been dated confidently. One species has been named Haikouichthys, another Yllokunminmgia. They were identified as fish from their gills and from a zigzag arrangement of muscles found only in fish.

— The Guardian

New information technology
by B.R. Sood

OVER the past 30 years computers and computer-based information technology (IT) have made inroads into everyday life and at places have changed lifestyles dramatically. This trend shall definitely continue with accelerated speed. The rate of computer technology development has surpassed the expectations of even the most optimists. Special emphasis has been laid to make computers user-friendly so as to increase their acceptability and to make their utilisation more widespread. Despite some marked successes a number of snags still persist in this area and there is, of course, plenty of scope for improvement. For making the computer technology more acceptable there is need for giving it a human touch. Moreover, network of computer and information technology has to be much more broadbased and multipurpose in nature. It is only under these conditions that benefits of the information age technological revolution shall be shared equitably.

To make a quantum leap from the existing state of affairs there is a need for developing software and hardware systems that are radically different and novel in a number of ways. With these objectives in view Laboratory for Computer Science at the prestigious Massachusets Institute of Technology in the USA has launched a gigantic research project named ‘‘Oxygen’’ that is expected to become as pervasive as oxygen that people breath for survival.

Prof M.L. Dertouzos, laboratory director, is of the opinion that root cause for computers being not very much user-friendly lies in the fact that scientists and technologists have so far tried to cater the technology to what machines want. The issue of human needs and the mode in which these needs can be catered to in a natural way have not been paid enough attention. Therefore, it is absolutely necessary for shifting from machine-oriented to human-oriented mindset. This crucial paradigm shift forms the basis of the project ‘‘Oxygen’’. Prof Dertouzos has a vision: people should be able to use new information technology to do more by doing less. New technology shall enter human lives in a natural way and not the other way around. Identities of the new technology will become synonymous with useful tasks they perform for the benefit of humanity. It is pertinent to remember that a computer so far has not gone beyond a fancy gadget and a desktop icon. New technology of the next century would increase human productivity manifold. For that to take place it is imperative that human-machine communication becomes more direct and as natural as possible and that people in large numbers have access to computer technology. As of today only 1.6 per cent of world population has access to computers and reap their benefits.

The project ‘‘Oxygen’’ is expected to provide the needed breakthrough for achieving the objectives highlighted above. This project is expected to tackle the challenges thrown up by the changing demands of computer and information technology. The project ‘‘Oxygen’’ is going to be a fully integrated collection of eight technologies created specially for information revolution of the 21st century. Key component is a hand-held gadget (called Handy 21) which has an inbuilt computer, a camera, a visual display, infra-red detectors in addition to being a cellular phone.

Through a set of computers (called Enviro 21) strategically placed in environment where people are more likely to be such as home, office, car etc, Handy 21 can communicate with a global network called Net 21. Net 21 could just be a number of satellites around the globe.

Handy 21 can be carried around like a cellular phone. It communicates with Enviro 21 locally and with Net 21 through Enviro 21 for long range interaction.

1. Rockets are used in fireworks, for conducting research, in warfare and for launching satellites which have wide applications. On which basic law is the operation of a rocket based?

2. Name the Russian school teacher who worked out mathematically the equations governing single and multi-stage rockets. Name also the American physicist who built and launched the world’s first rocket in 1926.

3. US scientists will soon conduct the world’s most sensitive experiment to search for extra terrestrial intelligence using a radio telescope whose receivers can detect 28 million possible signals coming from hundreds of star systems. What name has been given to this massive experiment?

4. What is common about lead azide, mercury fulminate, tetracene and styphnate?

5. What name is given to an organism that obtains its food from dead and decaying matter by secreting enzymes onto the organic matter to digest it?

6. PDT is a new technique of cancer treatment in which a laser excites a device called photosensitizer which burns the cancerous tumour. What does PDT stand for?

7. Looking mirrors are given a coating at the back to increase their reflecting power. Which chemical compounds are generally contained in this coating?

8. What name is given to a device that can transmit sound using a light beam? Who discovered this device and in which year?

9. Doctors sometimes conduct tests on cells and tissues taken out from a body organ for diagnosis. What is this technique called?

10. What is the name of India’s first nuclear reacter that literally means a heavenly damsel or a water nymph?

Answers:

1. Newton’s third law (to every action there is an equal and opposite reaction) 2. Konstantan E. Tsiolkovsky; Robert H. Goddard 3. Project Phoenix 4. These are primary explosives generally used in detonators (devices that set off other explosions) 5. Saprotroph 6. Photodynamic theraphy 7. Ammonical silver nitrate, red lead and form aldehyde 8. Photophone; US inventor Alexander Graham Bell in 1880 9. Biopsy 10. Apsara.

Unimobile released

GRAY Cell has released the beta version of an integrated instant messaging, e-mail management and the Internet services tool delivered via mobile devices and desktop PC.

Code-named Unimobile, the first ever Internet consumer product from India, is a desktop software that enables users of mobile devices and PCs to send instant messages, select personal e-mail delivery options and receive customised Internet services - all on a single interface on the desktop, mobile device or both.

The beta preview version of Unimobile is currently available for free download at www.unimobile.com. The product is scheduled for full-feature release in first quarter of 2000.

Cisco Systems

CISCO Systems Inc., the worldwide leader in networking for the Internet, has announced that it is joining forces with 10 leading companies to drive open standards for the broadband wireless Internet services.

At the core of this coalition is a new technology that delivers two-way data, voice and video communications over the air to both home and business, enabling high speed services to comparable to today’s most advanced cable networks.

The new wireless technology works well in congested cities, suburban and rural environments by overcoming the line-of-sight, distance reach, subscriber coverage, installation, and antenna size problems of existing proprietary wireless systems mainly in lower frequency microwave bands.

TrueNet

KRONE Communications Ltd and Prestolite Wire Corporation have jointly launched TrueNet, the world’s first cabling system to effectively prevent throughput loss in local area networks. TrueNet is tuned to protect the total efficiency of the network.

TrueNet goes beyond ensuring category 5, 5e or 6 compliance. The structured cabling comes with a revolutionary warranty, offering a five year throughput warranty guaranteeing zero bit error rate performance over and above the 20-year all inclusive industry standards compliance guarantee.

Many companies have undiagnosed problems where mismatched components cause impedance in their Ethernet cabling systems. These problems can diminish network performance without the users ever realising that it is the cabling system that is causing data errors and slowing down throughput.

New notebook PCs

DELL Computer Corporation, the world’s leading direct computer systems company, has announced two new latitude C-family corporate notebook PCs with faster processor, dual-pointing options and enhanced graphics capabilities that offer customers a range of performance and value options. Dell also introduced a new CD-Read/Write module for all latitude C-family notebooks.

The Latitude CPx H500GT features the latest Intel Mobile Pentium III processor at 500 MHz. The Latitude CPx also features the new Dell DualPoint design that integrates two cursor pointing devices - a touch pad and a pointing stick. Designed to improve usability, DualPoint lets customers use either device or both.

The notebook comes with 8 MB of video RAM and 2X AGP support for smooth video performance on its 14.1 inch TFT display. It also supports up to 512 MB RAM, one of the largest capacities in the industry.

Dell also announced a new addition to its CPt line that is targeted to price-sensitive institutional customers such as government and education. Like the high performance CPx, the CPt offers the Dell DualPoint device and 8 MB of Video memory.

The company also introduced new computer systems with the fastest Intel Pentium III processors based on the 0.18 micron process manufacturing technology, advanced transfer cache with advanced system buffering capabilities, thus providing significant performance enhancements over processors of the same clock speed with older technology.

MFG/PRO 9.0 launched

QAD, developer of supply chain-enabling enterprise software, has announced the launch of its MFG/PRO 9.0 enterprise software. The new version features next level architecture, a net user interface that is 100 Java and a set of e-business applications available for use on both the Internet and intranets.

QAD/Connects is the name used to describe the new architecture available with QAD 9.0 software, which offers flexible connectivity between itself and the four major entities it interfaces with users, information sources, other applications and e-business.

The new e-business facet of the solution makes available sales force automation and Internet enabled consumer and trading partner transactions with e-commerce.

Nasscom's offices

THE national Association of Software and Service Companies (Nasscom) would open offices in Silican valley later this year and another in London and Tokyo to facilitate Indian companies to compete there.

Nasscom’s overseas office would offer incubation marketing, business contacts, networking, lobbying and venture capital information services.

The measure is part of Nasscom’s effort to act as a nerve centre between Indian software, Internet, e-commerce companies with U.S. clients, venture capitalists, academicians, angel investors and to put at least 30 more Indian companies on overseas stock exchanges in next five years.

— R.Suryamurthy/Gaurav Choudhury