TECHNO

 

PSLV-C20 launches seven satellites

India’s polar satellite launch vehicle continued with its success streak on 25th  February 2013, launching Indo-French satellite SARAL and six other satellites from Austria, Britain, Canada and Denmark. The 23rd launch of PSLV -20 the 22nd consecutive success — also marked the second highest number of satellites being flown in a launch vehicle by the Indian Space Research Organization (Isro). The launch was delayed by five minutes because of a possible interference of space debris.

 The launch at the Satish Dhawan Space Centre  at Sriharikota, 100km north of Chennai. The 44.4m PSLV carrying a payload weighing 668.5kg lifted off from the launch pad .

Saral, built by Isro, would study the ocean surface and environment using two French devices — ARgos and ALtila, based on the principle of radar. The other satellites riding piggyback are two micro-satellites UniBRITE and BRITE from Austria and AAUSAT3 from Denmark and STRaND from the UK, besides a microsatellite (NEOSSat) and a mini satellite (SAPPHIRE) from Canada.ISRO had postponed the SARAL launch from December last year after it detected some technical inconsistencies.

अग्नि’ परीक्षण के बाद ‘रीसैट’ का सफल प्रक्षेपण

 

भारतीय अंतरिक्ष अनुसंधान संगठन यानी इसरो ने रीसैट-1 नाम के उपग्रह का सफल प्रक्षेपण किया है. श्रीहरिकोटा के सतीश धवन अंतरिक्ष केंद्र से प्रक्षेपित किया गया ये उपग्रह यानी सैटेलाइट रीसैट-1 इसरो का अब तक का भारत का सबसे भारी उपग्रह है इसे ध्रुवीय उपग्रह प्रक्षेपण वाहन यानी पीएसएलवी-सी 19 के ज़रिए गुरूवार की सुबह लगभग पौने छह बजे प्रक्षेपित किया गया.

रिमोट सेंसिग सेटेलाइट: इस उपग्रह का उपयोग आपदाओं की भविष्यवाणी, कृषि और रक्षा क्षेत्र में किया जाएगा. इससे फसलों की पैदावार के बारे में जानने और खासकर आपदा प्रबंधन के वक्त भी काफी मदद मिलेगी.ये हर तरह के मौसम जैसे घने कोहरे, बादल, तेज गर्मी, चक्रवात, कोहरे में भी तस्वीरें लेने में सक्षम है. इस उपग्रह का कार्यकाल पांच वर्ष का है

अग्नि-5 :मिसाइल प्रौद्योगिकी और सैन्य प्रतिरोधक क्षमता हासिल करने के लिए लंबी छलांग लगाते हुए बुधवार को भारत ने अपनी 5000 किमी मारक क्षमता वाली अंतर महाद्वीपीय बेलेस्टिक मिसाइल [आईसीबीएम] का परीक्षण करने की पूरी तैयारी कर ली है। यह परीक्षण कल ओड़िशा तट के पास व्हीलर द्वीप स्थित परीक्षण स्थल से किया जाएगा। अग्नि 5 को पूरी तरह से विकसित करने में और एक साल लगेगा। पिछले साल नवंबर में डीआरडीओ ने भारतीय प्रतिरोधक क्षमता को नई ताकत प्रदान करते हुए 3500 किमी मारक क्षमता वाली अग्नि 4 मिसाइल का परीक्षण किया था।अधिकारियों ने बताया कि अग्नि 5 तीन स्तरीय, पूरी तरह से ठोस ईंधन पर आधारित तथा 17 मीटर लंबी मिसाइल है जो विभिन्न तरह के उपकरणों को ले जाने में सक्षम है। दुनिया में अभी तक केवल अमेरिका, रूस, फ्रांस और चीन के पास आईसीबीएम को संचालित करने की क्षमता है।

इंटरनेट की अभूतपूर्व निगरानी शुरू

Scientists replicating human brain with computers

The “brain” is intended to combine all the information so far uncovered about its  mysterious workings -and replicate them on a screen, right down to the level of individual cells and molecules, says the team behind the project.The scientists hope to complete it in 12 years.  If it works, it could be revolutionary for understanding devastating neurological diseases such as Alzheimer’s, and even shedding light on how we think, and make decisions.

NASA’s Viking robots found life on Mars 36 years ago

A new analysis of 36-year-old data, resuscitated from printouts, shows that NASA found life on Mars, an international team of mathematicians and scientists have revealed.The analysis was based on studying the mathematically complexity of the results of a life-detection experiment conducted by NASA’s Viking Mars robots in 1976. The idea is that living systems are more complicated than purely physical ones, a concept that can be represented mathematically. 

Further, NASA doesn’t need a human expedition to Mars to nail down the claim, neuropharmacologist and biologist Joseph Miller, with the University of Southern California Keck School of Medicine, told Discovery News.  “The ultimate proof is to take a video of a Martian bacteria. They should send a microscope — watch the bacteria move,” Miller said.  “On the basis of what we’ve done so far, I’d say I’m 99 percent sure there’s life there,” he added. 

Researchers crunched raw data collected during runs of the Labeled Release experiment, which looked for signs of microbial metabolism in soil samples scooped up and processed by the two Viking landers. 

Ka versus Ku-band: what makes the difference in VSAT technology? With plenty of capacity and the capability to cater for broadband services, Ka-band has become the band of choice for many satellite operators and numerous Ka-band satellites are either already in orbit or are being readied for launch. But how does it compare to Ku-band? What are the technical advantages and disadvantages?

In the past few years we have witnessed a growing amount of Ka-band capacity launched in many regions of the world. Fueled by the growth in Internet-based applications, the demand for satellite capacity has grown similarly to other wireline and cellular wireless communications technologies. As a result of the growing demand for satellite bandwidth and as lower Ku-band frequency capacity has filled up in most of the geosynchronous (36,000km above the earth) orbital slots, Ka-band became the next choice for launching new satellite capacity.

In this article we will now explore the main differences between the two frequency bands, and the corresponding main characteristics of satellite and VSAT technologies. Ka frequencies (~30GHz uplink & ~20GHz downlink) are almost twice the frequency used by Ku (~14GHz uplink and ~12GHz downlink). When high frequencies are transmitted and received in a heavy rain fall area, a noticeable signal degradation occurs and is proportional to the amount of rain fall (commonly known as known as “rain fade”). The higher frequency the more a signal is susceptible to rain fade. A typical Ku-band rain fade rate is ~1dB/sec while the fade rate in Ka-band is significantly higher at around 3-5dB/sec.

Most new Ka-band satellites implement spot-beam technology to reuse the frequency band across the desired coverage area. As opposed to wide beams that cover large territories (e.g. all of Eu- rope), spot beams cover much smaller territories (1/50 – 1/100 ofthe large territory). In addition, because of the wider spectrum available on Ka-band and the need to support many beams, Ka-band satellites typically implement wide transponders (300MHz – 600MHz), about 10 fold compared with the typical 27MHz to 54MHz Ku-band transponders. This type of implementation combined with advanced VSAT transmission technology results in Ka-band satellites with 10X- 100X the throughput available on traditional Ku-band satellites. No wonder that the new generation of Ka-band satellites are also called High Throughput Satellites or HTS.

Service throughput speeds

On the service side, the market trend is to increase the service throughput speeds in at least one order of magnitude compared to existing Ku-band or older generation Ka-band satellites. If standard Ku-band service speeds today are 1-2Mbps, the new services are expected to be 10-20Mbps. These new high-speed services are comparable to 4G, LTE cellular and multi Mbps services available on standard DSL, cable, and fibre technologies.

The new service requirements and high capacity Ka-band satellites introduce new challenges to the VSAT ground segment equipment manufacturers in the following three areas:

• VSAT CPE terminals which need to be low cost must support very high throughput and provide competitive performance level while mitigating the impact of over 500msec of round trip delay that is a result of pure physics – signals still need to traverse 36,000km to and from the satellite.

• Hub systems need to support multiple beams, many high throughput forward and return channel carriers, dynamically adapt to changes in signal levels and rain fade conditions, and support multiple Gbps of aggregate throughput.

• Management systems will need to configure, monitor and control dozens of hub systems, multiple gateways, and 10s to 100s thousand of VSAT terminals.Gilat has taken the initiative with the SkyEdge II VSAT system, which was designed and developed to address these new require-ments. The following are the main technology attributes related to Ka-band systems:

• One of the key elements in VSAT performance is acceleration technology. Most VSAT systems have implemented TCP and HTTP acceleration to improve the performance of web-based applications. As demand for Internet-based applications increases, web site implementations become content richer, and because many home users have multiple PCs, tablets and smartphones, these legacy acceleration technologies are no longer sufficient to deliver adequate performance.

• Gilat’s recently announced CacheMode technology combines a multi GByte advance cache memory built-in to the VSAT with distributed cache system that takes advantage of the one-to- many multicast transmission inherent to satellite technology to deliver and populate the on-board cache. The ability to deliver and store large amount of web content closer the end user, results in higher performance to web-based applications and lower satellite space segment utilisation.

• Adaptive outbound and inbound transmission mechanisms are mandatory in any VSAT system supporting Ka-band satellites to mitigate the high signal fade rate in Ka-band frequencies. Standard DVB-S2 Adaptive Coding and Modulation (ACM) technology provides partial solution and it is available in most VSAT system only for the forward channel. Gilat VSAT systems include dynamic Inbound Coding and Modulation technology and a high power 4W Ka-band transceiver and Automatic Uplink Power Control to provide the highest dynamic range possible.

These technologies make the inbound frequency band completely resilient to changes in weather, other atmospheric conditions and network utilisation. With dynamic inbound carriers reconfiguration implemented automatically 40 times every second, the system will guarantee constant network wide throughput at any given time.

• Wider transponders and higher bit-rate services require advanced modulations to provide maximum carrier throughput. Gilat SkyEdge II system is the first in the market to implement and deploy tens of thousands of node networks using 16APSK modulation in the outbound and 8PSK modulation in the inbound. And, current equipment is ready to take advantage of 32APSK modulation when satellite design will enable us to close the link at a, not so long ago unthinkable, four bits/symbol 32APSK modulation.

• System scalability, modularity and management are fundamental elements in Gilat SkyEdge II network architecture. These concepts provide a cost effective system that can support multiple beams with different load levels under a single management systems that can support tens of thousands nodes. Ka-band is not just the next generation frequency band expansion to Ku. It encompasses new type of satellite architecture, new transmission and bandwidth management challenges to provide higher quality, better performance and faster speeds services. These new technologies and services are natural evolution to the VSAT market making it an equal member in the evolution of the entire telecommunication industry. 

“ On the service side, the market trend is to increase the service throughput speeds in at least one order of magnitude compared to existing Ku-band or older generation Ka-band satellites. ”

Most precise measurement of universe revealed

 Researchers have shed light on how ancient sound waves sculpted the cosmos, thus revealing the most accurate measurements ever made of the large-scale structure of the universe between five to seven billion years ago. 

Physicists on the Baryon Oscillation Spectroscopic Survey (BOSS) attained this by observing the primordial sound waves that propagated through the cosmic medium about 30,000 years after the Big Bang, the Discovery News reported.  And until now, the data supports the theory that our universe as flat, constituting roughly a quarter cold dark matter, and four percent ordinary matter, with the rest made up of a mysterious force dubbed “dark energy.” A hundred years ago scientists thought that the universe was steady and unchanging. Einstein invented the cosmological constant to expand the fabric of space-time after his own equations for general relativity wouldn”t allow for the cosmos to remain static as expected in a steady state universe. 

Soon after, astronomer Edwin Hubble discovered that the universe was in fact expanding, consistent with Einstein’s original general relativity theory. Einstein then removed his cosmological constant describing his failure to predict an expanding universe in theory before it was proven by observation, as his biggest blunder. 

In 1998, astronomers studying distant exploding stars called a Type 1A supernovae found that not only was the universe expanding, but that the rate of expansion was accelerating because of some type of unknown force or dark energy. 

This bore a striking resemblance to Einstein’s cosmological constant. Either that, or our theory of gravity is incomplete. Answering this question is one of the foremost challenges in 21st century cosmology. 

This new measurement from BOSS is important because that time frame – five to seven billion years ago – is the period when dark energy “turned on.” The BOSS findings will help physicists find out the exact nature of whatever is triggering our universe to accelerate in its expansion. 

The discovery that led to the theory of dark energy depended on studying the red shifts of bright light from supernovae. BOSS, in contrast, looks at baryonic acoustic oscillation (BAO). 

This phenomenon is the consequence of pressure waves (sound, or acoustic waves) propagating through the early universe in its earliest hot phase, when everything was just one big primordial soup. 

Those sound waves created pockets where the density varied in regular intervals or periods, a “wiggle” pattern suggestive of oscillation, or vibration. Then the universe cooled adequately for ordinary matter and light to go their separate ways, the former condensing into hydrogen atoms.

Russia joins ESA for exploratory robotic mission to Mars

Russia’s federal space agency Roscosmos and the European Space Agency (ESA) are set to conduct an ExoMars joint project on Mars exploration. According to the Roscosmos, the two sides would sign a final agreement in November after confirming financial details of the project. ExoMars, which is currently under development by the ESA, is a robotic mission to Mars for searching possible biosignature of Martian life. Initially, the project envisaged the launch of a mission to Mars orbit in 2016, followed by landing a ground vehicle in 2018 with the participation of the U.S. National Aeronautics and Space Administration (NASA).

ESA turned to Russia for support after NASA refused to provide the project with an Atlas-5 rocket as a carrier to deliver a space vehicle to Mars.

Radio telescope ALMA opens its eye on Universe

One of the world’s largest ground-based astronomical projects is being installed 16,597 feet above sea level in Chile’s Atacama Desert, which will help the oxygen-deprived scientists flocking to this region to study the origins of the universe.  Opened last October, the Atacama Large Millimeter/submillimeter Array, known as ALMA, will have spread 66 radio antennas near the spine of the Andes by the time it is completed next year. 

The 1.35-billion-dollars telescope, a joint project by the United States, the European Union, Canada, Chile, Japan and Taiwan, will explore some of the darkest, coldest, farthest, and most hidden secrets of the Cosmos. ALMA, the Atacama Large Millimeter/sub millimeter Array, which is under construction, is currently using 16 large antennas to see wavelengths of light that are much longer than what the human eyes can see. Eventually it will use 66 antennas

Science & Technology : Atomic Energy

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