With the 48-hour countdown for the takeoff of the Polar Satellite Launch Vehicle (PSLV-C-12) having begun at 6.45 a. m. on Saturday, the vehicle carrying two satellites is all geared up to rocket into the sky at 6.45 a. m. on Monday, from Andhra Pradesh's Sriharikota spaceport.

The two satellites that the PSLV will put in orbit include a radar imaging satellite called RISAT-2, and a 38-kg investigational mini communication satellite - Anusat - built by Anna University, Chennai.

London, April 18 : Scientists are working on ways to build a gossamer-thin space sail or "aerobrake" that would help bring back a used rocket back to Earth safely.

According to a report in New Scientist, space-flight engineers Max Cerf and Brice Santerre at the European aerospace firm EADS Astrium have put the idea forward.

London, April 18 : In a new research, a team of scientists has found that global warming is not just transforming the land for the Arctic people, but it is also poisoning their food, with mercury levels in seals and beluga whales reaching levels that would be considered unsafe in fish.

According to a report in New Scientist, Gary Stern of Canada's Department of Fisheries and Oceans in Winnipeg, Manitoba, and colleagues did the research.

They found that seal meat contains more mercury in low-ice years, suggesting the problem will only get worse.

London, April 18 : At a meeting in the US city of Baltimore, parties to the Atlantic Treaty have adopted proposals to limit tourism in Antarctica, in a bid to protect the fragile ecosystem of the continent.

According to a report by BBC News, the parties agreed at the meeting to limit the size of cruise ships visiting Antarctica and the number of tourists taken ashore.

Limiting tourism has taken on urgency due to a surge in visits and a number of cruise ship accidents.

Washington, April 18 : A new study has revealed that the Moon dust, which causes hazards like ruining scientific experiments and endangering astronauts'' health, is influenced by the Sun''s elevation.

Lunar dust has long been described as the No. 1 environmental hazard on the Moon.

It causes miscellaneous havoc: from destroying scientific equipment deployed on the lunar surface, to creating blinding dust clouds that interfere with lunar landings.

Washington, April 18 : A new study conducted by Stony Brook University researchers suggests that feeling bored in marriage leads to substantially less marital satisfaction even nine years later.

Research leaders Irene Tsapelas and Arthur Aron, who worked in collaboration with University of Michigan researcher Terri Orbuch, interviewed 123 U. S. married couples seven years into their marriage, and then again, nine years later, 16 years into their marriage.