SCIENCE & TECHNOLOGY

Big leap for the Indian space programme
Radhakrishna Rao

The successful testing of the fully Indian designed and developed cryogenic engine stage on November 15 marks a significant milestone in the quest of the Indian Space Research Organisation (ISRO) to attain self-reliance in the launching of satellites from the Indian soil.

Trends
Robots mingle with cockroaches
Roman bath found
Fish that lives out of water

Prof Yash Pal

Prof Yash Pal

PROF YASH PAL
THIS UNIVERSE 

What are stem cells?
We are made up of cells that carry genetic information and act like sophisticated factories capable of self-multiplication. We start with a small number of cells in an embryo. The genetic information therein controls their development and multiplication. As they multiply they must differentiate to handle multifarious jobs of construction and operation.

 


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Big leap for the Indian space programme
Radhakrishna Rao

The successful testing of the fully Indian designed and developed cryogenic engine stage on November 15 marks a significant milestone in the quest of the Indian Space Research Organisation (ISRO) to attain self-reliance in the launching of satellites from the Indian soil.

This indigenous cryogenic engine stage will now replace the Russian supplied upper stage of the three-stage GSLV, the most powerful space vehicle built by ISRO. Moreover, this high performance engine would enable GSLV launch a 2.5-tonne class satellite into a geostationary transfer orbit—36,000 km above the equator where a satellite appears stationary with respect to earth. On a more practical plane, a fully indigenous GSLV would end India’s dependence on the European Ariane space vehicle for getting the INSAT series of domestic spacecraft off the ground.

Incidentally, the first two stages of 49-metre tall, 414-tonne GSLV are derived from the modules of the four-stage Polar Satellite Launch Vehicle (PSLV) which features alternate liquid and solid fuel stages. The first stage o f GSLV is one the largest rocket motors in the world and uses Hydroxyl Terminated Poly-butadiene (HTPB) based propellant. The second stage as well as the four strap-on motor use liquid propellant engine derived from PSLV.

Significantly, GSLV was declared operational after both its developmental test flights conducted in April 2001 and May 2003 were successful. In its first operational flight, GSLV successfully launched India’s first exclusive satellite for educational services EDUSAT in Sept 2004. And during Sept 2006, a GSLV mission taking off from the Satish Dhawan Space Centre (SDSC) in Sriharikota island successfully orbited India’s INSAT-4CR communications spacecraft. The next GSLV flight featuring a fully Indian cryogenic engine stage would launch G-Sat-4 technology demonstrator satellite.

With the full-flight duration test for 720 seconds carried out, Liquid Propulsion Systems Centre (LPSC) of ISRO at Mahendragiri in Tamil Nadu, decks have been cleared for the integration of this cryogenic engine stage with the GSLV flight vehicle. It may be recalled that a ground test for 480 seconds of the complete cryogenic engine stage was completed in August 2007.

The Indian cryogenic stage is powered by re-generatively cooled engine which works on staged combustion cycle developing a thrust of 69.5-kN in vacuum. In addition to this main engine, the stage incorporates insulated propellant tanks, booster pumps, inter stage structures, fill and drain systems, pressurisation systems, gas bottles, pyro valves and cold gas orientation and stabilisation system. According to ISRO, this successful ground testing of the cryogenic upper stage for the full flight duration has validated the design robustness and performance adequacy for this use in GSLV.

ISRO took up the challenge of developing India’s own cryogenic engine in 1990s after it was forced by the USA to drop its plan to transfer cryogenic engine technology to India on the ground that it violated the Missile Technology Control Regime. Of course, Russia did agree to supply half a dozen cryogenic engines so that India would be in a position to operate the GSLV till its own cryogenic engine gets ready.

As pointed out by ISRO, cryogenic stage is technically a very complex system compared to solid or earth storable propellant stages due to the use of propellants at extremely low temperatures and the associated thermal and structural problems.
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Trends
Robots mingle with cockroaches

Tiny robots programmed to act like roaches were able to blend into cockroach society, according to researchers studying the collective behavior of insects. Cockroaches tend to self-organise into leaderless groups, seeming to reach consensus on where to rest together.

For example, when provided two similar shelters, most of the group tended to gather under the same one.

Hoping to learn more about this behavior, researchers led by Jose Halloy at the Free University of Brussels, Belgium, designed small robots programmed to act like a cockroach. — AP

Roman bath found

Israeli archaeologists have unearthed the remains of a second century terraced street and bath house which provide vital clues about the layout of Roman Jerusalem.

The Israel Antiquities Authority said the 30-metre (90-foot) alley was used by the Romans to link the central Cardo thoroughfare with a bath house and with a bridge to the Temple Mount, once the site of Jerusalem's ancient Jewish temple.

"We find bits of Roman road all the time but this discovery helped us piece together a picture of Roman Jerusalem," Jon Seligman, Jerusalem regional archaeologist, told Reuters at the site. "It was a real Eureka moment." — Reuter

Fish that lives out of water

A tropical fish that lives in mangrove swamps across the Americas can survive out of water for months at a time, similar to how animals adapted to land millions of years ago, a new study shows.

The Mangrove Rivulus, a type of small tropical killifish, seeks refuge in shallow pools of water in crab burrows, coconut shells or even old beer cans in the tropical mangrove swamps of Belize, the United States and Brazil.

When their habitat dries up, they live on the land in logs, said Scott Taylor, a researcher at the Brevard County Environmentally Endangered Lands Program in central Florida.

The fish, whose scientific name is Rivulus marmoratus, can grow as large as three inches. They group together in logs hollowed out by insects and breathe air through their skin instead of their gills until they can find water again. — Reuters

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THIS UNIVERSE 
PROF YASH PAL
What are stem cells?

We are made up of cells that carry genetic information and act like sophisticated factories capable of self-multiplication. We start with a small number of cells in an embryo. The genetic information therein controls their development and multiplication. As they multiply they must differentiate to handle multifarious jobs of construction and operation. In many respects they become specialists. But it seems too much to demand that the tasks of all the progenies down the line are defined right in the beginning. If it was done by a supreme designer and architect, He would have realised that unforeseen special capabilities and constraints would be required at different stages of development and hand books for accomplishing these jobs cannot to be lugged around all the time. It would be better if all the cells have potent capability for what might be required but the specialists get trained and honed depending on the stage of development. Enormous self-learning capability has to be built in and specialists develop by themselves. However, once you become a specialist you cannot change your job — you have to remain only a restricted specialist.

On the other hand if you are not a specialist, as in the beginning, you are multi-potent. You are a baby but you can learn to do anything that is required. You are a stem cell!

It is clear, therefore, that a boxful of stem cells is all we need to address most of the malfunctions of our body as we grow. All organs could be rebuilt. Whole of the body machinery could be renewed. That is the promise. Though some work has been done in this area, so far the dreams are much bigger than the accomplishment. An obvious problem in pursuing this research is that there are not many ways to go back to the first baby stage of our cells. They could be harvested from aborted embryos or the blood of the umbilical cord. But you cannot store them for long. All collections of original cells have a natural urge to subdivide and grow — they are alive. That means they also start on their journey of specialisation. You cannot force babies to remain babies. I am told even in this regard also some work shows promise.

Perhaps I can use this discussion to develop an analogous argument for the value of little children for learning what to teach them — to think of them as a renewing resource and not as clay to be molded to fit the world that we have made. They have questions and curiosities which we grownups encounter less and less. We like to move in grooves that seem immutable to our adult minds. Lot of problems in the present day world and some of its worrisome questions can be put in ways that do not come to us easily.

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