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Venus Express
ljk4-1
post Feb 17 2006, 06:56 PM
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QUOTE (Rakhir @ Feb 17 2006, 11:56 AM) *
Successful Venus Express main engine test
http://www.esa.int/esaCP/SEMVX5MVGJE_index_0.html

One hundred days after beginning its cruise to Venus, ESA’s Venus Express spacecraft successfully tested its main engine for the first time in space.


-- Venus Express Status Report: Continued Spacecraft Testing

http://www.spaceref.com/news/viewsr.html?pid=19665

-- Venus Express Status Report: Start of Second Payload Pointing Campaign

http://www.spaceref.com/news/viewsr.html?pid=19664

-- Venus Express Status Report: Main Engine Calibration Test

http://www.spaceref.com/news/viewsr.html?pid=19668

-- ESA Venus Express Status Report: No. 13 - Spacecraft Thermal Characterisation

http://www.spaceref.com/news/viewsr.html?pid=19667

"Main Engine calibration burn has shown a working Main Engine thus giving the
green light for the last mandatory sub-system to be used for the Venus Orbit Insertion.

By coincidence the Main Engine calibration burn took place on mission day 100. During
the reporting period operations have been moved back to the Cebreros station and this
will be used as prime station from now onwards."


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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ljk4-1
post Feb 22 2006, 07:06 PM
Post #137


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Venus Express Ground Observing Project

The Venus Express Ground Observing Project (VEXGOP) is an opportunity to
contribute scientifically useful images and data to compliment the Venus Express
(VEX) spacecraft observations of Venus. The project will focus on utilising the
capabilities of advanced amateurs to obtain images of the atmosphere of Venus;
specifically filtered monochrome images obtained with CCD based cameras in the
350nm to 1000nm (near ultraviolet, visible and near infrared range).

The Venus Express (VEX) spacecraft will observe the planet Venus using seven
instruments for at least two Venusian years (1000 days) beginning in May 2006.
The instrument package includes the Venus Imaging Camera (VMC), which will image
the planet in the near-UV, visible and near-IR range. Although VMC will provide
much higher resolution images of the planet than visible from Earth, continuous
monitoring of the planet will not be possible.

There may be periods, therefore, when parts of the planet are visible from Earth
that are not visible from the spacecraft (due to the spacecraft position in
orbit). Additionally it is important to compare Earth-based observations with
simultaneous spacecraft observations. In particular this will allow us to extend
our understanding of the dynamics of Venus’s atmosphere based on the VEX data
to observations made prior to the VEX mission, as well as after completion of
VEX operations.

Objectives

The objectives of VEXGOP is to obtain high quality images of Venus before, after
and during VEX operations. Amateur astronomers, using CCD based cameras with
filters for specific band passes in the near ultra-violet, visible and near
infrared wavelengths (350nm to 1000nm), are encouraged to participate in the
gathering of images. Observation campaigns will include:

* Routine images of Venus during each apparition

* Coordinated observations during specific periods of the VEX mission to
provide either simultaneous or complimentary ground based images to VEX
spacecraft observations

For more details go to:

http://sci.esa.int/science-e/www/object/in...fobjectid=38833


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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Rakhir
post Mar 7 2006, 07:38 AM
Post #138


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Successful Trajectory Correction Manoeuvre

http://sci.esa.int/science-e/www/object/in...fobjectid=38887

On 24 February a Trajectory Correction Manoeuvre was executed in order to trim the spacecraft trajectory after the Main Engine calibration manoeuvre. The manoeuvre executed flawlessly but the current knowledge of the orbit indicates that it is very likely that another fine tuning will be required once the orbital knowledge has increased.
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Rakhir
post Mar 13 2006, 12:51 PM
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Preparation for Venus Approach

http://sci.esa.int/science-e/www/object/in...fobjectid=38933

All calibration, science and maintenance activities of the instruments have been completed and focus is now on the Venus approach phase.
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Rakhir
post Mar 27 2006, 11:32 AM
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VOI Events Timeline (11 April) :
- Spacecraft reorientation starting at 08:03 (CEST)
- 51 min engine burn starting at 09:19
- Reacquisition of radio contact after a 10 min occultation at 09:56

http://www.esa.int/esaCP/SEMJITM65LE_index_0.html
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Rakhir
post Mar 31 2006, 03:42 PM
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New VOI timeline (slight modifications compared to previous release) :
- 09:17 --> VEX main engine burn starts
- 09:45 --> Occultation starts (loss of S-band signal)
- 09:55 --> Occultation ends
- 10:07 --> VEX main engine burn ends
- 10:10 --> Announcement by Flight Operations Director
- 11.07 --> X-band transmitter on
- 11:12 --> Telemetry received
- 11:30-12:15 --> Press Conference

All times above are 'Earth Received' time (CEST)

http://www.esa.int/SPECIALS/Venus_Express/SEMMM0NFGLE_0.html
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ljk4-1
post Apr 3 2006, 02:08 PM
Post #142


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No.12-2006 – Paris, 31 March 2006

Venus within ESA probe reach

After its five-month, 400 million kilometre journey inside our solar system
following its lift-off on 9 November 2005, ESA’s probe Venus Express will
finally arrive on 11 April at its destination: planet Venus.

Venus Express mission controllers at the ESA Space Operations Centre (ESOC) in
Darmstadt, Germany are making intensive preparations for orbit insertion. This
comprises a series of telecommands, engine burns and manoeuvres designed to slow
the spacecraft down from a velocity of 29000 km per hour relative to Venus, just
before the first burn, to an entry velocity some 15% slower, allowing the probe
to be captured into orbit around the planet.

The spacecraft will have to ignite its main engine for 50 minutes in order to
achieve deceleration and place itself into a highly elliptical orbit around the
planet. Most of its 570 kg of onboard propellant will be used for this
manoeuvre. The spacecraft’s solar arrays will be positioned so as to reduce the
possibility of excessive mechanical load during engine ignition.

Over the subsequent days, a series of additional burns will be done to lower the
orbit apocentre and to control the pericentre. The aim is to end up in a 24-hour
orbit around Venus early in May.

The Venus orbit injection operations can be followed live at ESA establishments,
with ESOC acting as focal point of interest (see attached programme). In all
establishments, ESA specialists will be on hand for interviews.

ESA TV will cover this event live from ESOC in Darmstadt. The live transmission
will be carried free-to-air. For broadcasters, complete details of the various
satellite feeds are listed at http://television.esa.int.

The event will be covered on the web at venus.esa.int. The website will feature
regular updates, including video coverage of the press conference and podcast
from the control room at ESA’s Operations Centre.

Media representatives wishing to follow the event at one of the ESA
establishments listed below are requested to fill in the attached registration
form and fax it back to the place of their choice.

For further information, please contact:

ESA Media Relations Division

Tel : +33(0)1.53.69.7155
Fax: +33(0)1.53.69.7690

Venus Express Orbit Insertion – Tuesday 11 April 2006

ESA/ESOC, Robert Bosch Strasse, 5 – Darmstadt (Germany)

PROGRAMME


07:30 Doors open

08:45 Start of local event, welcome addresses

09:10 ESA TV live from Mission Control Room (MCR) starts
09:17 Engine burn sequence starts
09:45 Occultation of spacecraft by Venus starts
09:55 Occultation ends
10:07 Main engine burn ends
10:20 Address by Jean-Jacques Dordain, ESA’s Director General, and other
officials

Break and buffet
Interview opportunities

11:30-12:15 Press Conference
Jean-Jacques Dordain, Director General, ESA
Prof. David Southwood, Director of Science, ESA
Gaele Winters, Director of Operations and Infrastructure, ESA
Manfred Warhaut, Flight Operations Director, ESA
Håkan Svedhem, Venus Express Project Scientist, ESA
Don McCoy, Venus Express Project Manager, ESA

13:15 End of event at ESOC

Venus Express Orbit Insertion – ESA/ESOC Darmstadt – 11 April 2006

First name: _________________________ Surname: __________________________
Media: ________________________________________________________________
Address: _______________________________________________________________
Tel: _______________________________ Fax: ________________________________
Mobile : ____________________________ E-mail: ______________________________

I will be attending the Venus Express Orbit Insertion event at the following
site:

( ) Germany
Location: ESA/ESOC
Address: Robert Bosch Strasse 5, Darmstadt, Germany
Opening hours: 07:30 – 13:00
Contact: Jocelyne Landeau-Constantin, Tel: +49.6151.902.696 – Fax:
+49.6151.902.961

( ) France
Location: ESA HQ
Address: 8/10, rue Mario Nikis – Paris 15, France
Opening hours: 08:00 – 13:00
Contact: Anne-Marie Remondin – Tel: +33(0)1.53.69.7155 – fax: +33(0)1.53.69.7690

( ) The Netherlands
Location: Newton Room, ESA/ESTEC
Address: Keplerlaan 1, Noordwijk, The Netherlands
Opening hours: 08:30 – 12:30
Contact: Michel van Baal, tel. + 31 71 565 3006, fax + 31 71 565 5728

( ) Italy
Location: ESA/ESRIN
Address: Via Galileo Galilei, Frascati (Rome), Italy
Opening hours: 07:00 – 14:00
Contact: Franca Morgia – Tel: +39.06.9418.0951 – Fax: +39.06.9418.0952

( ) Spain
Location: ESA/ESAC
Address: Urbanización Villafranca del Castillo, Villanueva de la Cañada,
Madrid, Spain
Opening hours: 8:30 - 13:30
Contact: Monica Oerke, Tel + 34 91 813 13 27/59 – Fax: + 34 91 813 12 19


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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The Messenger
post Apr 3 2006, 05:28 PM
Post #143


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It looks like the ESA is making a very real effort to allow the public to witness the orbital insertion - complete with a mission scientist news conference. Does anyone know if NASA will patch the broadcast through on the NASA channel?
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RNeuhaus
post Apr 4 2006, 08:18 PM
Post #144


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QUOTE (ljk4-1 @ Apr 3 2006, 09:08 AM) *
Over the subsequent days, a series of additional burns will be done to lower the
orbit apocentre and to control the pericentre. The aim is to end up in a 24-hour
orbit around Venus early in May.

That paragraph has paid me the attention. So fast in getting an orbit of 24 hours without any aerobraking in one month instead of 6 months of aerobraking that MRO must has to be performed in order to attain an orbit of less than 450 km around of the Mars' surface from the initial orbit of 420 km at pericenter and 48,000 km at apocenter.

It is understand that the MRO must have undergone further orbit adjustments that VEX does not perform but just will remain a highly elliptical orbit within 250 km of the planet's surface and withdraw to distances of up to 66,000 km.

The VEX's pericenter is no lower than 250 kilometers from Venus' surface, that means that at that height there won't be any aerobraking due to the atmosphere resistance. Then the Venusian atmosphere limit would be lower than 250 kilometers? For a comparisions, the Mars limit atmosphere is similar to Earth's ones but little higher by few tens kilometers and the Venusian atmosphere is almost twice higher than Earth?

Rodolfo
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RNeuhaus
post Apr 5 2006, 04:30 PM
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Venus Express is going as cool toward the hot Venus:

The Venus approach phase is proceeding according to plan with all activities conducted successfully.

A Trajectory Correction Manoeuvre of about 13 cm s-1 has been executed in the evening of 29 March to reduce the pericenter altitude at Venus arrival by a bit more than 100 kilometres. The latest calibration of the nominal TCM gives the following results (uncertainties are 1-sigma):

* magnitude error = -1.2 mm/s (-0.9% +/- 2.1%)
* direction error = 0.8 deg +/- 0.3 deg

The final calibration will be made on 3 April. The current orbit determination does not show the need for any further trajectory correction.


Targeting for Venus Orbit Insertion

Rodolfo
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The Messenger
post Apr 5 2006, 04:56 PM
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QUOTE (RNeuhaus @ Apr 4 2006, 02:18 PM) *
The VEX's pericenter is no lower than 250 kilometers from Venus' surface, that means that at that height there won't be any aerobraking due to the atmosphere resistance. Then the Venusian atmosphere limit would be lower than 250 kilometers? For a comparisions, the Mars limit atmosphere is similar to Earth's ones but little higher by few tens kilometers and the Venusian atmosphere is almost twice higher than Earth?

Rodolfo

Yes, it is much more dense, about 9x. There was a theory floating around a few years ago, that without the Earth's magnetic field, the solar wind would blow the atmosphere away. I don't know what became of this, but I don't see how Venus, with no magnetic field and much closer to the sun, could have an atmosphere at all, if the theory were true unsure.gif
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Rakhir
post Apr 7 2006, 11:47 AM
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Two new articles for the preparation of the VOI.

ESA’s Venus Express to reach final destination
http://www.esa.int/esaCP/SEM0UGNFGLE_index_0.html
Some information on observations to be performed in capture orbit.


Final Preparations for Orbit Insertion
http://sci.esa.int/science-e/www/object/in...fobjectid=39059
The fuel and oxidizer tanks have been pressurised and the helium tank is being warmed-up to properly sustain the main engine burn.
On 7 April, the essential commands for the VOI burn will be uplinked to the spacecraft.
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ljk4-1
post Apr 10 2006, 04:38 PM
Post #148


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Drama in mission control

ESAPod goes to the heart of Venus Express and meets with a veteran ESA
operations engineer in the mission control centre. The large, well-equipped Main
Control Room enables flight controllers to work as a focussed team during
critical events and gives them the central facilities they need to communicate
with support teams worldwide.

Listen to this ESAPodcast at:

http://www.esa.int/SPECIALS/ESApod/SEMCVLNFGLE_0.html


ESA’s Venus Express to reach final destination

It was on 9 November last year that ESA's Venus Express spacecraft lifted off
from the desert of Kazakhstan onboard a Soyuz-Fregat rocket. Now, after having
travelled 400 million kilometres in only about five months, the spacecraft is
about to reach its final destination. The rendezvous is due to take place on 11
April.

Full story :

http://www.esa.int/esaCP/SEM0UGNFGLE_index_0.html


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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ljk4-1
post Apr 10 2006, 07:01 PM
Post #149


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Monday, 10-Apr-2006

On 11 April, Venus Express will arrive at Venus and enter orbit around the
planet. The spacecraft's main engine will perform a 50 minute burn, starting
around 07:10 UT, to slow the spacecraft and allow it to be captured by Venus's
gravity.

Updates on the Venus Orbit Insertion (VOI) activities will be posted on the page

http://sci.esa.int/jump.cfm?oid=39060

and on the ESA Portal Venus Express website

http://www.esa.int/SPECIALS/Venus_Express/index.html

ESA TV will broadcast live coverage of the event. For details see

http://television.esa.int


===================================================
KEEP IN TOUCH

+ SCITECH RSS
Subscribe to SciTech's RSS (Really Simple Syndication) feeds to get the latest
updates delivered directly to your desktop.
http://sci.esa.int/science-e/www/object/in...fobjectid=37599

+ SCITECH SCREENSAVER
Don't forget to download the SciTech Screensaver a multi-facetted application
that allows you to keep abreast of status reports, news and announcements of
events taking place at ESA Science.
http://sci.esa.int/jump.cfm?oid=34651


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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RNeuhaus
post Apr 10 2006, 07:27 PM
Post #150


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The start time of VOI : 7:07:59 UTC. That zone time corresponds to Greenwich line?

Rodolfo
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