ISRO developing reusable launch vehicle

A model of Re entry launch vehicle (RLV)

ISRO‘s design of the Reusable Launch Vehicle-Technology Demonstrator (RLV-TD) has been approved by the National Review Committee. An ISRO official said design-related issues have been addressed and presented to the National Review Committee and clearance obtained to go ahead to build the RLV-TD.

The space agency, as a first step towards realizing a Two-Stage To Orbit (TSTO) re-usable launch vehicle, has developed a winged RLV-TD. ISRO, in its recently released annual report, stated that design options have been finalized. Besides, the mission design has been completed with a revised vehicle mass. The RLV-TD will act as a flying test-bed to evaluate various technologies — hypersonic flight, autonomous landing, powered cruise flight and hypersonic flight using air breathing propulsion.

The first in the series of trials is the Hypersonic Flight Experiment (HEX) followed by the landing experiment (LEX), Return Flight Experiment (REX) and Scramjet Propulsion Experiment (SPEX).

During HEX, the vehicle will take lift off in the form of a rocket with a booster. Later, it can be recovered from sea. Though the trials for the first experiment are slated to take place this year, an Isro official said the launch date for carrying out HEX from the Satish Dhawan Space Centre in Sriharikota has not been fixed. The development and flight testing of the Reusable Launch Vehicles-Technology demonstrator missions leading to Two-Stage To Orbit (TSTO) is part of India’s Space Vision 2025 and is expected to bring down cost significantly.

ISRO, in January 2007, conducted the Space capsule Recovery Experiment (SRE-1). Launched by the Polar Satellite Launch Vehicle (PSLV-C7) from Satish Dhawan Space Centre on January 10, 2007, the capsule was successfully recovered on January 22, 2007, from the Bay of Bengal.

Homemade Spacecraft

An ingenious father-and-son duo in New York launched a HD video camera tied to a weather balloon 30 kms above the earth into the stratosphere and share footage that their camera captured in its incredible 100-minute journey. To get back the camera intact, they also attached an iPhone as a GPS device to send its coordinates upon landing to a cell phone tower. The video reveals that the camera, tied to a parachute that auto-inflated when the balloon burst due to atmospheric pressure, landed safely just 30 miles away from where it was launched.

Video from a camera attached to a weather balloon that rose into the upper stratosphere and recorded the blackness of space.

Homemade Spacecraft from Luke Geissbuhler on Vimeo.
 

Two big black holes found together

Two colossal black holes appear to be orbiting one another in sort of a cosmic minuet at the center of a faraway galaxy formed when two separate galaxies collided, U.S. astronomers said on Wednesday.

These two so-called super massive black holes, which are celestial objects with enormous gravitational pull, are locked in orbit about 5 billion light years away from Earth, the scientists said. A light year is about 6 trillion miles (10 trillion km), or the distance light travels in a year.

Data from Apache Point Observatory in New Mexico provided the best evidence to date of two black holes orbiting each other. This is known as a binary system, according to astronomer Todd Boroson of the National Optical Astronomy Observatory in Tucson, Arizona.

Scientists believe all or most galaxies have super massive black holes at their center. For example, our Milky Way galaxy has a black hole at its center that is about 3 million times the mass of the sun.

When galaxies collide and merge, as they do relatively often, the black holes at their center may gravitate toward one another because of their great mass, entering into orbit as these two appear to be doing.

Boroson said orbiting black holes eventually may merge into an even larger single black hole. While scientists think binary black holes may be relatively common, they have been elusive.

Boroson and fellow National Optical Astronomy Observatory astronomer Tod Lauer detected these two by spotting the radiation emitted by objects apparently being sucked into the black holes by their gravitational pull.

The smaller of the black holes is about 20 million times the mass of our sun, while the larger one is a billion times the sun's mass, the scientists wrote in the journal Nature.

"We've discovered that there's a pretty good correlation between the size of a black hole and the size of the galaxy that it's in. This could be a case where a big galaxy ate a smaller galaxy. These two black holes take about a hundred years to orbit each other and are located about three-tenths of a light year from each other”, Boroson said.

Scientists solves astronomy mystery

In a new research, scientists have solved the longstanding astronomy mystery of how massive stars form without blowing away the clouds of gas and dust that feed their growth.

The research, by Lawrence Livermore National Laboratory, University of California, Santa Cruz and UC Berkeley, has shown how a massive star can grow despite outward-flowing radiation pressure that exceeds the gravitational force pulling material inward.

Using 3-D radiation hydrodynamics simulations, the group, which includes Livermore’s Richard Klein, who also is an adjunct professor at UC Berkeley, and his LLNL post doc Andrew Cunningham, unexpectedly discovered that these massive stars also tend to occur in binary or multiple star systems.

Richard Klein, an adjunct professor at UC Berkeley said: “Originally, we were just exploring the physics of massive star formation. As we were looking at the physics, we found that gravitational instabilities cause companion stars to form around massive stars.

Logically, we thought the massive amounts of radiation pressure would stop the star in its tracks from growing any larger. But instead, gravitational instabilities channeled gas onto the star system through disks and filaments, sort of like fingers, that self-shield against the radiation, while allowing the radiation to escape through optically thin bubbles.

Massive stars produce so much light that the radiation pressure they exert on the gas and dust around them is stronger than their gravitational attraction, a circumstance that has long been expected to prevent them from growing by accretion.

Mark Krumholz, lead author and an assistant professor of astronomy and astrophysics at the UC Santa Cruz said: “We didn’t set out to solve that question, so it was a nice side benefit of the study. The main finding is that radiation pressure does not limit the growth of massive stars. The team spent years developing complex computer codes for simulating the processes of star formation.

Combined with advances in computer technology, their latest code (called ORION) enabled them to run a detailed 3-D simulation of the collapse of an enormous interstellar gas cloud to form a massive star.