Science & Technology GK Questions with Answers – Page 8

A marine biologist, he led the first Indian scientific expedition to Antarctica in 1981, a voyage that established India's presence on the continent and paved the way for accession to the Antarctic Treaty and for Consultative Party status in 1983.

The National Centre for Polar and Ocean Research is at Vasco-da-Gama in Goa and works under the Ministry of Earth Sciences.

Himadri was opened in 2008 at Ny-Alesund on the Svalbard archipelago, which belongs to Norway. Svalbard is governed by a treaty that allows the nationals of its parties to carry on research and economic activity there, which is what makes an international research village at Ny-Alesund possible.

Bharati was commissioned in 2012 at the Larsemann Hills on the coast of east Antarctica, roughly three thousand kilometres from Maitri.

Maitri was commissioned in 1989 on the rocky Schirmacher Oasis, a narrow ice-free strip, next to the freshwater lake named Priyadarshini.

It was built during the Indian expedition of 1983 to 1984 in Queen Maud Land and was India's first permanent base on the continent.

The long-standing guideline of the Inter-Agency Space Debris Coordination Committee, formed in 1993 and including ISRO among its member agencies, is that a spacecraft or upper stage leaving the low Earth orbit protected region should be de-orbited, or placed in an orbit from which it will re-enter, within twenty-five years…

Its full name is the Convention on International Liability for Damage Caused by Space Objects, and it fixes responsibility on the state that launches or procures the launch of a space object.

A communication satellite nearing the end of its life keeps a small reserve of fuel to raise itself out of the crowded geostationary ring into a higher orbit where it cannot drift back into a working slot or collide with an active satellite.

In February 2009 the working American communication satellite Iridium 33 and the defunct Russian military communication satellite Kosmos 2251 struck each other over Siberia at a relative speed of several kilometres per second.

NETRA stands for Network for Space Objects Tracking and Analysis. It is ISRO's programme to build radar, optical telescope and control centre capability for space situational awareness, so that India can detect, track and catalogue objects in orbit and warn its own satellites about possible close approaches instead of depending…

In Mission Shakti an interceptor developed by the Defence Research and Development Organisation was launched from Dr. A. P. J. Abdul Kalam Island off the Odisha coast and destroyed India's own Microsat-R satellite in low Earth orbit at a height of about 283 kilometres.

Kessler, then working with the American space agency, published the argument that once the population of objects in low Earth orbit crosses a certain density, collisions between them will generate fragments faster than the atmosphere can drag the old debris down.

Global Positioning System satellites orbit at about 20,200 kilometres, which lies in the medium Earth orbit band stretching from 2,000 kilometres up to the geostationary height of 35,786 kilometres.

The British science fiction writer and engineer set out in 1945 how three satellites placed in a circular equatorial orbit at about 36,000 kilometres could relay radio signals to almost the whole inhabited world.

Such an orbit is near-polar, typically 600 to 900 kilometres high with an inclination of about 98 degrees, which makes it retrograde.

A geostationary satellite must match the rotation of the Earth with respect to the distant stars, and that rotation takes one sidereal day.

Only at this height does a satellite in a circular equatorial orbit take exactly one sidereal day to complete a revolution, which is the condition for appearing stationary above one point on the Earth.

A fifty-one per cent attack is one in which a single party commands a majority of the resource that decides consensus, which is the mining power in a proof of work chain and the staked coins in a proof of stake chain.

The Central American country passed a Bitcoin Law in June 2021 and became, in September 2021, the first state anywhere to give bitcoin the status of legal tender alongside the United States dollar, which it already used as its currency.