VEX Science Planning Options

[cndwrld]

Hello-

I wasn't sure how most people would like to see stuff posted. Or if this would interest many people. But in the interests of putting out more information, I created this topic as a place to put information on Venus Express science planning.

If you have any ideas about this, let me know.

Cheers-

Don Merritt

[cndwrld]

MTP012 Science Plan

The time span of the MTP012 operations is the following:
START: Orbit 324 (pericenter on 11 March 2007, DOY070)
END: Orbit 351 (pericenter on 07 April 2007, DOY097)

The MSP contains one MTP. One MTP contains 4 Command Periods (CPs) of one week (7 days). In total the MTP covers 28 days of operations.


Science Plan Overview

MTP012 includes the end of mission phase #5, phase # 6 and the beginning of Phase 7. In the first orbits, conditions for the off-pericenter night side observations will be fulfilled. This period provides good conditions for observations of the night side and atmospheric sounding in solar occultation geometry (eclipse season 3). Solar occultation observations will be used to study composition and structure of the atmosphere above the cloud top. Campaigns of cases #2 repeated in several consecutive orbits will be used to study composition and dynamics of deep atmosphere on the night side. Conditions will be also favourable for observations of nightglows to study composition and dynamics of the thermosphere and search for lightning. Limb observations in forward scattering geometry (spacecraft in eclipse) will provide good opportunity to study vertical structure of hazes above the main cloud.

Relatively high downlink rate would allow the experiments to use high resolution operation modes to study small scale features and dynamics.

Thermal mapping of the surface and search for active volcanism will be performed in this phase. Two bi-static sounding experiments are scheduled.

VSOC has been alerted (Peter Jenninskens, personnel communication) that meteor showers are likely to occur on orbits 326, 329, 331 and 338. The meteors are expected to have their peak brightness at about 100-115 km altitude. The most promising wavelength range would be a narrow band at 777 nm, where meteors may generate atomic oxygen emission from the dissociation of CO2. The forbidden line at 577 nm may also be observed in the meteor’s wake. Magnesium emissions at 280 and 285 nm may be also detected on the dayside. One atmosphere-grazing fireball track may have been observed by the Pioneer Venus Orbiter Ultraviolet Spectrometer instrument orbiting Venus in 1979. The satellite measured three correlated spectra during orbit 75 containing a strong NO (C-X) emission at 155-257 nm, which was confined in the Venus atmosphere in a narrow band at least 900 km in length and less than 5 km wide.

The following observations are proposed in this MTP:
• 15 solar occultation measurements (case #6) will be given relatively high priority in order to achieve good latitude coverage. This will cover the themes:
o Cloud layer and haze
o Atmospheric composition
o Atmospheric dynamics
o Atmospheric structure
o Escape processes.

• Four limb observations (case #7), to study vertical structure of haze layers. This will cover the themes:
o Cloud layer and haze
o Atmospheric composition
o Atmospheric dynamics.

• Two bi-static sounding experiments are planned, covering the theme: Surface properties and geology.

• Plasma and magnetic field measurements on the nightside and on the dayside, covering the theme Plasma environment/escape processes.

• 27 cases 2 at apocenter and 21 cases 1 at pericenter are considered, covering basically all themes.

MTP012 Medium Term Planning was completed 22 December 2006. Short term planning has begun, with delivery of files for the upcoming command period from the VEX Science Operations Center at ESTEC (European Science and Technology Center, Noordwijk, The Netherlands) to the flight control team at ESOC (European Space Operations Center, Darmstadt, Germany). All communications with the spacecraft are performed via the facility in Cebreros, Spain (50 Km west of Madrid).

Worth noting is that the flight control team and flight dynamics team at ESOC have performed extremely well in every phase of the mission; if there has been a human-induced error from them, it doesn't come to mind. And the three engineers at the science operations center with whom I work have done an amazing job for being such a small team with such a never ending amount of work. And our TEC department at ESTEC has been unsung heros for getting us better and better tools so we can keep on doing it.

Hope this is useful-

Don Merritt