well...there's still orbit insertion.
but hopefully that will all go well. in the meantime: hooray!

"....well...there's still orbit insertion...."

Mars Observer, lost during orbit insertion preparation.
Mars Climate Orbiter, lost in atmosphere during unsurvivable accidental areo-CAPTURE attempt.
Mars-4 and Nozomi both could not attempt orbit insertion burn.

85% is probably a fair arm-waving assessment of the risk fraction for an orbiter mission.

- First star tracker switched on.
- Reaction wheels switched on.
- Venus Express achieved Normal Mode indicating full 3 axis stabilised conditions and full control through ground operations.

http://sci.esa.int/science-e/www/object/in...fobjectid=38250

Rakhir

Maybe, nobody will be able to answer it for forever....! That is a big question that its original axis has turned down or maybe it started so on the contrary to the rest of planets.

Rodolfo

The upper atmosphere of Venus SEEMS to be less fickle, and there is a little less mission time delay - so there are some minor odds movers. The big intangable is solar flare-ups - some of those burps look like they could eat Messinger or Express.

Anyway, the atmosphere should not be a problem because VE will not use aero-capture... unless a huge navigational error or unit of measure conversion error like it was for MCO

Rakhir

But ESA will claim important new discoveries sooner than that.

It's sad, but my elation over the purpose of the mission is so moderated by the fact that it's ESA doing the data release. I think we just need to psychologically prepare ourselves as though this were a 2008 mission and be happy to see the results trickle in eventually.

Venus' upper atmosphere is MUCH more stable, density-wise, than Mars' -- simply because Mars' total atmosphere is so thin that the heating from dust storms can cause the atmosphere as a whole to dramatically warm, and thus balloon upwards in Mars' weak gravity. In fact, it was stated by a speaker at the COMPLEX meeting that this is the one piece of new environmental engineering measurements we absolutely MUST have for near-future Mars missions even of the unmanned variety: a satellite to monitor Martian weather and its correlation with upper-atmospheric density fluctuations in much more detail than has yet been done. We came within a hair of losing the Spirit rover even BEFORE it also ran into those high-speed near-surface winds (which, by the way, are less important for a throttled-rocket soft lander), because Mars' upper air density was 10% less than even the worst-case prediction based on obsevations the week before the landing, and so the vehicle was braked much less during entry than expected.

Are you meaning that ESA's data policy is not the right one? Maybe JAXA's is better...

Where do you get all this stuff? I have been looking for the descent profiles for Spirit and Opportunity for a year now!

It's certainly not good enough - that is without doubt.

Doug

I am looking forward to the great discovery of the fact that the visible imaging channels can't see through to the surface.

I got that from Jay Bergstralh's talk on the problem at COMPLEX -- but there have been some notes scattered around previously on the Web on the subject, though I'd have to track them down. (Bergstralh obligingly included a graph, which I'd never seen before, of the precise degree to which MER-A's air-density readings were below the 12-27-03 estimate -- the zone giving most of the trouble was 20-50 km, and at one point the density was fully 12% below the worst-case prediction. MER-A came down so much faster than predicted that had it popped its chute 3 seconds later, it would have crashed.)

The EDL data is on the PDS - but it's a bit awkward to use - the derived stuff is in there, I'll see if I can put Pathfinder, Spirit and Oppy pressure profiles together.

Doug

Thanks Bruce and Doug - I guess I need to bite the bullet and figure out how to extract from the PDS, but doesn't look friendly, and it would be easy to spend days, and still not have confidence I had extracted the right data.

I'm looking forward to the day when the ESA is sitting on so much embargoed data, that they loose track of the release dates and open the floodgates. An ESA-PDS?

Well MEX stuff is already in the PDS, and ESA opperate their own pseudo-PDS-tool at http://www.rssd.esa.int/index.php?project=PSA - problem being, due to the nature of HRSC data, it's basically impossible to use

Doug

Spacecrafts are flying labs, not handy cameras to take snapshots to be shown worldwide on the run... Data have to be received, processed, verified... That's not so spectacular as NASA's rovers landing on Mars, for instance, but that's what science is... B.T.W., Huygens lander's policy was not very different to Spirit's or Opportunity's...

I know all of that, more than well enough.

The Huygens policy is very different to the rovers. We are almost 12 months from landing, and the full instrument data set is not online. If it were MER, it would have been online for 6 months already.

MSSS and Themis team offer a useable, intuitive interface for Mars Orbiter data, the MEX HRSC data is almost unuseable and barely accesable.

ESA press releases are infrequent, inaccurate and often make idiotic claims that are untrue and unfounded.

It's not just an image releasing strategy that ESA lacks by a long long way

Doug

While I agree that the ESA press releases can be exaggerated (infinitely more data?), I can't blame them for wanting to hold onto the data for a while. Nobody has landed anything on Titan before, and as Europe hasn't had much of a space program compared to the US I'm sure they want to impress as much as possible.

Personally, I'm happy with the images they've released thus far. I think that once the ESA has something definitive to say regarding the data they'll say it. I can't think of any benefit for them to holding onto the data forever, unless maybe they're just scouting for rare minerals (and they'd lose all credibility in that case).

It seems to me a difference between releasing data because you want people to be able to access it versus releasing it to the public simply because you are being made to.

Any Earth departure images planned?

Anyway, I think that there is science on the one hand and marketing on the other...

It will take some images, for calibration purposes, but quite far away from the Earth. There are no further scientific activities planned for the cruise phase.

The critical Launch and Early Orbit Phase (LEOP) for Venus Express was completed today.
The spacecraft is performing flawlessly.

Trajectory Correction Manoeuvre (TCM-1) was successfully completed.
The craft is now on the exact trajectory required for Venus Orbit Insertion in five months' time.

With LEOP running so smoothly, controllers were able to bring forward some platform commissioning activities, which were originally planned for the weekend.

With the start of the Near Earth Commissioning Phase, payload activities are due to start on 18 November; these initial switch-on and test activities are scheduled to be complete by 14 December.

http://www.esa.int/SPECIALS/Venus_Express/SEMK9UJBWFE_0.html

Rakhir

Platform Completes near Earth Commissioning.
The remaining testing activities on the platform side will take place in January (thermal characterization) and in February (main engine calibration).

Payload Commissioning Underway : MAG, VIRTIS, and VMC.
During this period the Earth-Moon observation is planned

http://sci.esa.int/science-e/www/object/in...fobjectid=38323

the earth data cubes from VIRTIS look very promising! Imagine seeing all the cloud layers of venus with this! and even the surface! (sorry just being a bit excited )

http://www.esa.int/esaCP/SEMOIGULWFE_index_0.html

Venus Express - End of Near Earth Commissioning Phase

During the reporting period the last activities of the Near Earth Commissioning
have been completed according to the plan. Two slots with the New Norcia ground
station have been dedicated to test the performance of the TTC subsystem and of
the Ultra Stable Oscillator (USO) for the radio science experiment (VeRA). In
both occasions problems in operating the ground station equipment have affected
the test.

http://sci.esa.int/science-e/www/object/in...fobjectid=38473

VENUS EXPRESS STATUS REPORT

Report for Period 16 December 2005 - 05 January 2006

During the reporting period the spacecraft has been configured for a passive cruise phase and the only activities conducted on top of the routine ones are the DDOR tests with ESA (NNOCEB) and DSN (GDS-CAN) stations.

http://sci.esa.int/jump.cfm?oid=38559

At the end of the last NNO pass in the reporting period (DOY 006, 06:00) Venus Express was 15.5 million km from the Earth, 131.7 million km from the Sun, and 25.5 million km from Venus. The one-way signal travel time was 52 seconds.

VE is already above than 38% of distance from Earth.

Future Milestones

The coming week will mark a "close to inferior conjunction" condition, therefore, no major operations are planned. The actual conjunction condition will be reached on DoY 011 at around 18:00 when the angular distance between the Sun and the spacecraft as seen from the Earth will be approximately 1.6 degrees. No significant impact is foreseen on the RF link.

http://www.spacedaily.com/news/Venus_Expre...ase_Begins.html

Rodolfo

An interesting milestone today : We are at the halfway point of the 153 days cruise phase.

And it's already a couple of days that VE is closer from Venus than from Earth.

On January 19th, Venus Express was 21.9 million km from the Earth and 19.2 million km from Venus.

http://sci.esa.int/science-e/www/object/in...fobjectid=38648

Rakhir

Venus Express articles in ESA Bulletin Number 124 online here:

http://www.esa.int/SPECIALS/ESA_Publicatio...W3IMZCIE_0.html

Contents

Venus Express: The Mission Begins

The Venus Express Mission
Donald McCoy, Thorsten Siwitza & Roy Gouka

Venus Express: The Spacecraft
Alistair J. Winton et al.

The Science Return from Venus Express
Håkan Svedhem, Olivier Witasse & Dmitri V. Titov

Venus Express Ground Segment and Mission Operations
Manfred Warhaut & Andrea Accomazzo

ESA’s New Cebreros Station Ready to Support Venus Express
Manfred Warhaut, Rolf Martin & Valeriano Claros

The Roadmap for a GMES Operational Oceanography Mission
Mark Drinkwater et al.

A Tsunami Early-Warning System
– The Paris Concept
Manuel Martin-Neira & Christopher Buck

EGNOS Operations and Their Planned Evolution
Laurent Gauthier et. al.

The BGAN Extension Programme
Juan J. Rivera, Eyal Trachtman & Madhavendra Richharia

Subscribe to the printed version of the ESA Bulletin free of charge. Visit our Bookshop for ordering information.

Thanks, this is really interesting background.
But the pedant in me can’t help but quibble at the following quote from the Venus Express Mission section:

“… surface temperatures reach 470C (about ten times higher than the hottest temperature on Earth), “

I know it’s outreach and all, but that’s simply wrong, conceptually wrong. 470C (~740K) is about 2.5 times Earth surface temperature.

It's about 10 times higher above FREEZING than the highest temperatures on Earth, which presumably is what they meant to say.

Continued Spacecraft Testing
http://sci.esa.int/science-e/www/object/in...fobjectid=38746

During next week the Main Engine pressurisation and calibration will take place.
After the Main Engine burn, an eventual correction will be done one week later.

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."

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

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.

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.

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

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

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

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?

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

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

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

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.

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

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


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

Rodolfo