Monday, November 30, 2015

LISA-Pathfinder spacecraft to unlock gravitational wave astronomy technologies

CAPE CANAVERAL, Fla. -- A European spaceprobe designed to test new technologies for use on future spacecraft designed to study the ripples of gravitational waves in outer space is poised to lift-off on Wednesday from French Guiana.

The Laser Interferometer Space Antenna (LISA) Pathfinder is a two-part technology test bed designed to spend six months providing engineers new research for future gravitational wave detectors. The understanding of these waves will provide scientists with a better understanding of the space-time connection with general relativity which was predicted by Albert Einstein in his General Theory of Relativity.

In addition to the LISA Technology Package, which will operate during the first three months, is the NASA contributed Disturbance Reduction System (DRS) module. The DRS has a compliment of two clusters of micro propulsion thrusters and a computer with control software designed to create a "drag-free" flight path for the spacecraft enacted only by outside gravitational forces.

Europe's space program is working toward creating a series of ground stations to study gravitational waves in deep space in partnership with the upcoming Einstein Telescope and the eLISA observatory scheduled for launch around 2030. LISA will open the window for the advanced study of gravitational wave astronomy.

Europe's light weight Vega rocket is scheduled to launch the LISA Pathfinder mission on December 1 at 11:15 p.m. EST (4:15 GMT on Dec. 2) from the Kourou Space Centre located on the edge of the Amazon Rain Forest. Following a normal launch, the spacecraft will then separate at 1:00:34 a.m. from Vega's upper stage after being place in an elliptical orbit of 1540 by 207 km.

"LISA Pathfinder is a complex mission," Flight Director Andreas Rudolph said on Sunday. "Even after we’re safely in space, we will have to make seven or eight thruster burns in the first 10 days to take it as safely as possible through Earth's radiation belts and get it onto the correct trajectory."

An upbeat Rudolph remains grounded in the knowledge of several major mile markers LISA will need to achieve in the weeks leading to the first science points. "We won't arrive at around L1 until late in January, and until then teams will be working intensively to ensure that the thruster burns go as planned, that our navigation is correct and that we ensure the instruments and all flight systems are working normally."

A series of burns by LISA will place it around the Sun-Earth Lagrangian L1 point nearly 1.5 million km away from Earth and towards the Sun -- a journey of eight weeks from launch to L1 arrival. The spacecraft's exact orbit is designed to give LISA a quiet environment far away from a planet's influence, and at the same time in position to communicate with Earth based ground stations by way of X-band.

"X-band is typical for a craft that will voyage 1.5 million kilometres from Earth, but is not common for satellites in low orbit, which is where LISA Pathfinder starts out," Ground Operations Engineer Fabienne Delhaise explained. "This means our ground stations must point especially accurately and use a special adapter to catch signals just after separation, when the craft is still near Earth."

November marked the centennial anniversary of the publication of four papers authored by Einstein on his Theory of Relativity. The European Space Agency spokesperson Claudia Mignone notes "general relativity remains to date the best physical theory to describe gravity particularly on cosmic scales."

No comments:

copyright 1998 - 2010 Charles Atkeison, All rights reserved.