Indian ISRO PLSV rocket launches 5 satellites: Three minute delay to avoid space debris

The Monday morning blast off of an Indian Space Research Organisation (ISRO) PSLV rocket carrying five foreign satellites was delayed by three minutes to avoid a collision with space debris, the space agency said.

Despite the necessary delay, the Polar Satellite Launch Vehicle's (PSLV) carrying the five foreign satellites blasted off from the Indian Space Research Organization’s launch pad at Sriharikota in Andhra Pradesh in southern India at 09:52 a.m. local time.

With this launch, India has successfully put into orbit five foreign satellites from four different countries.

The rocket's main payload was the 714-kg French EADS Astrium Earth Observation satellite SPOT-7.

The other satellites are:

• 14-kg AISAT-1 of Germany (already transmitting signals from orbit); 
• NLS7.1 (CAN-X4) and NLS7.2 (CAN-X5) from Canada's University of Toronto Institute for Aerospace Studies' Space Flight Laboratory each weighing 15 kg (CanX-4 and CanX-5 form a dual nanosatellite formation flying a demonstration mission); and 
• 7-kg, 1U Cubesat VELOX-1 of Singapore.

The five satellites were launched under commercial arrangements that Antrix Corporation has entered into with the respective foreign agencies.

The flare star WX UMa becomes 15 times brighter in 160 seconds

A flare star. Credit: Casey Reed /NASA

Astrophysicists at the University of Santiago de Compostela Spain and the Byurakan Observatory (Armenia) have detected a star of low luminosity which within a matter of moments gave off a flare so strong that it became almost 15 times brighter.

The star in question is the flare star WX UMa.

"We recorded a strong flare of the star WX UMa, which became almost 15 times brighter in a matter of 160 seconds," explains the astrophysicist Vakhtang Tamazian, professor at the University of Santiago de Compostela. The finding has been published in the 'Astrophysics' journal.

This star is in the Ursa Major constellation, around 15.6 light years from the Earth, and it forms part of a binary system.

Its companion shines almost 100 times brighter, except at times such as that observed, in which the WX UMa gives off its flares. This can happen several times a year, but not as strongly as that which was recorded in this instance.

Dr Tamazian and other researchers detected this exceptional brightness from the Byurakan Observatory in Armenia.

"Furthermore, during this period of less than three minutes the star underwent an abrupt change from spectral type M to B; in other words, it went from a temperature of 2,800 kelvin (K) to six or seven times more than that."

Based on their spectral absorption lines, stars are classified using letters. Type M stars have a surface temperature of between 2,000 and 3,700 K; Type B between 10,000 and 33,000 K.

WX UMa belongs to the limited group of "flare stars", a class of variable stars which exhibit increases in brightness of up to 100 factors or more within a matter of seconds or minutes.

These increases are sudden and irregular – practically random, in fact. They then return to their normal state within tens of minutes.

Scientists do not know how this flaring arises, but they know how it develops: "For some reason a small focus of instability arises within the plasma of the star, which causes turbulence in its magnetic field," explains Tamazian.

"A magnetic reconnection then occurs, a conversion of energy from the magnetic field into kinetic energy, in order to recover the stability of the flow, much like what happens in an electric discharge."

More information: N. D. Melikian, V. S. Tamazian, R. Sh. Natsvlishvili, A. A. Karapetian. "Spectral observations of flare stars in the neighborhood of the Sun". Astrophysics 56 (1): 8-18, March 2013. link.springer.com/article/10.1007%2Fs10511-013-9263-z