Andrew Yee[_1_]
July 17th 08, 03:40 PM
ESA News
http://www.esa.int
17 July 2008
Closing in on Venus
Starting this week, spacecraft controllers have been executing a series
of manoeuvres to gradually bring Venus Express closer to its host
planet. In its modified orbit, the spacecraft will be able to observe
unexplored regions and investigate phenomena that were not within its
reach before.
The operational manoeuvres to bring the spacecraft closer will be
executed through the month of July, settling it into its new orbit by 4
August.
Until now, Venus Express has occupied a highly eccentric polar orbit: at
its closest point (pericentre), the spacecraft is between 250 km and 400
km from the planet, and at its farthest (apocentre), it is about 66 000
km away. The pericentre is located at 84 deg north.
This eccentric orbit was designed to facilitate observation of the
southern hemisphere for extended periods, and of the northern hemisphere
and the northern polar region at closer distances.
The altitude of the pericentre will now be lowered to between 185 and
300 km. This modification will enable the following science advantages:
* Study of the magnetic field in the northern polar region
* Study of the plasma environment deeper in the ionosphere
* To indirectly deduce the density of the planet's atmosphere by
measuring the force, or drag, exerted by the planet's atmosphere on the
body of the spacecraft as it moves closer to the planet
The lowering of the Venus Express orbit is the first step in a more
ambitious strategy, yet to be confirmed in its entirety. The intention
is to lower the spacecraft's orbit further into the atmosphere, such
that the drag on the spacecraft's body can be measured by the on-board
accelerometers.
As the next step, Venus Express may test aerobraking, a technique where
a spacecraft uses the force exerted by the planet's atmosphere to
decelerate and so significantly change its orbit in a controlled manner.
For more information:
Håkan Svedhem, ESA Venus Express Project Scientist
Email: Håkan.Svedhem @ esa.int
Octavio Camino, ESA Venus Express Spacecraft Operations Manager
Email: Octavio.Camino @ esa.int
[NOTE: An image and weblinks supporting this release are available at
http://www.esa.int/esaSC/SEM25EWIPIF_index_1.html ]
http://www.esa.int
17 July 2008
Closing in on Venus
Starting this week, spacecraft controllers have been executing a series
of manoeuvres to gradually bring Venus Express closer to its host
planet. In its modified orbit, the spacecraft will be able to observe
unexplored regions and investigate phenomena that were not within its
reach before.
The operational manoeuvres to bring the spacecraft closer will be
executed through the month of July, settling it into its new orbit by 4
August.
Until now, Venus Express has occupied a highly eccentric polar orbit: at
its closest point (pericentre), the spacecraft is between 250 km and 400
km from the planet, and at its farthest (apocentre), it is about 66 000
km away. The pericentre is located at 84 deg north.
This eccentric orbit was designed to facilitate observation of the
southern hemisphere for extended periods, and of the northern hemisphere
and the northern polar region at closer distances.
The altitude of the pericentre will now be lowered to between 185 and
300 km. This modification will enable the following science advantages:
* Study of the magnetic field in the northern polar region
* Study of the plasma environment deeper in the ionosphere
* To indirectly deduce the density of the planet's atmosphere by
measuring the force, or drag, exerted by the planet's atmosphere on the
body of the spacecraft as it moves closer to the planet
The lowering of the Venus Express orbit is the first step in a more
ambitious strategy, yet to be confirmed in its entirety. The intention
is to lower the spacecraft's orbit further into the atmosphere, such
that the drag on the spacecraft's body can be measured by the on-board
accelerometers.
As the next step, Venus Express may test aerobraking, a technique where
a spacecraft uses the force exerted by the planet's atmosphere to
decelerate and so significantly change its orbit in a controlled manner.
For more information:
Håkan Svedhem, ESA Venus Express Project Scientist
Email: Håkan.Svedhem @ esa.int
Octavio Camino, ESA Venus Express Spacecraft Operations Manager
Email: Octavio.Camino @ esa.int
[NOTE: An image and weblinks supporting this release are available at
http://www.esa.int/esaSC/SEM25EWIPIF_index_1.html ]