Title  Chemistry in the atmospheres of Venus and Mars
Pi     E. Lellouch
Time   70 hrs

1. Name of program and authors
Title: Chemistry in the atmospheres of Venus and Mars
Authors: E. Lellouch

2. One short paragraph with science goal(s)

Abstract: The chemistry of Mars and Venus atmospheres remains
   poorly understood, as in particular, few species have been
   detected while photochemical models predict more are present.
   Species such as O2, O3, H2O2, H2CO, NO should be observed 
   on Mars. For those species for which detection is certain
   (O2, O3, H2O2), spatial and seasonal variability, and correlation
   with water vapor variations should be studied. On Venus,
   species such as HCl, H2S, SO2, SO must be observed and monitored
   as possible tracers of active volcanism.


3. Number of sources : 2
   
   Mars
   Venus

4. Coordinates:

4.1. Rough RA and DEC 

     Variable

4.2. Moving target: yes/no (e.g. comet, planet, ...)

	Yes

4.3. Time critical: yes/no (e.g. SN, GRB, ...)

	Yes. Needs to be done at Mars opposition, and Venus inferior conjunction and/or
maximal elongation. Needs to be done at several Mars seasons (at least four) and 
repeated on Venus (once a year or so).

4.4. Scheduling constraints: (optional)


5. Spatial scales:


5.1. Angular resolution (arcsec): 1

5.2. Range of spatial scales/FOV (arcsec):  FOV = 10-60

     (optional: indicate whether single-field, small mosaic,
     wide-field mosaic...)

5.3. Required pointing accuracy: (arcsec) 1


6. Observational setup

6.1. Single dish total power data: required

     Observing modes for single dish total power: wobbler switch

     (e.g., nutator switch; frequency switch; position switch;
     on-the-fly mapping; and combinations of the above)
	

6.2. Stand-alone ACA: no

6.3. Cross-correlation of 7m ACA and 12m baseline-ALMA antennas: 
     required

6.4. Subarrays of 12m baseline-ALMA antennas: no


7. Frequencies:

7.1. Receiver band: Band  6, 7, 9
7.2. Lines and Frequencies (GHz): 

	SO2, H2S: 216.7 GHz
	SO: 220 GHz
	O3, H2O2: 363 GHz
	O16O18,H2CO: 234 GHz
	NO: 350 GHz
	HCl: 626 GHz
     
7.3. Spectral resolution (km/s): 1 for Venus, 0.1 km/s for Mars

7.4. Bandwidth or spectral coverage (km/s or GHz): 0.1 GHz for Mars, 8 GHz
for Venus.

8. Continuum flux density:

8.1. Typical value (Jy):

	Mars  : 200 K
	Venus : 300 K

8.2. Required continuum rms (Jy or K): 0.1 K

8.3. Dynamic range within image:

     (from 7.1 and 7.2, but also indicate whether, e.g., weak objects
     next to bright objects)

8.4. Calibration requirements: absolute      ( 10% )
                               repeatability ( 10% )
                               relative      ( 10% )


9. Line intensity:

9.1. Typical value (K or Jy): 2 K 
    
9.2. Required rms per channel (K or Jy): 0.05 K

9.3. Spectral dynamic range:

9.4. Calibration requirements: absolute      ( 10% )
                               repeatability ( 10% )
                               relative      ( 10% )

10. Polarization: no

10.1. Required Stokes parameters:

10.2. Total polarized flux density (Jy):

10.3. Required polarization rms and/or dynamic range:

10.4. Polarization fidelity:

10.5. Required calibration accuracy:


11. Integration time for each observing mode/receiver setting (hr):

1 hr per line for Venus, 2 h per line for Mars

12. Total integration time for program (hr):

~ 70 hours (2 planets x 4 epochs x 6 freqs x 1.5 hour in average)

13. Comments on observing strategy : Should be combined with DRSP 4.1.1 (thermal profile measurements)
and for Mars with DRSP 4.1.2 (water measurements)


--------------------------------------------------
Review v2.0:
 
Review 4.1.1-4.1.8

The only question I have with regards to these projects is the use of
ACA cross-correlated with ALMA-12m. Several projects list this option
as 'required' or as 'beneficial', but no arguments are given. 

- When listed as 'required' does this mean that the observations are
  mosaics, and that the ACA is needed to provide the intermediate
  scales? If so, are the cross-correlations with the ALMA-12m antennas
  needed, or could simultaneous ACA-7m-only observations also suffice?

- When listed as 'beneficial' is this purely for S/N reasons or also
  for uv-coverage? The cross-correlation option is fairly demanding on
  the scheduling, and unlikely to be used unless absolutely necessary.