1st venus flybymid-ir venus observations simultaneous close-up & distance observations mertis,...

1st Venus flyby

SWT BepiColombo – October 15th 2019

V. Mangano, J. Helbert E. Montagnon, F. Budnick, S. de la Fuente, M. Fraenz, & others

BepiColombo SWT19 | ESTEC 14 – 18 October 2019 | Page 3

Mission Status

56.4 Mio km from Earth (3 mn one-way light time)


g 12-Sep-19 to 13-Nov-19: EPCM2;n 1 thruster, MGA coverage;n End date uncertain depending on actual performance;

g Dec-19: Cruise Checkout #2;g Jan-20: weekly passes, MMO Checkout #2;g Apr-20: Earth Swingby;g Jun-20: Cruise Checkout #3;g Oct-20: Venus Swingby #1;

Upcoming Activities


g Oct-19: deadline for Payload / MMO Operations Requests;g End 2019: consolidation of closest approach date and swingby

geometry;g Dec/Jan-20: consolidation of pointing timeline with PIs (lead FD);g From Feb-20: increased pass frequency for navigation;g 25-Feb-20: EP touch-up slot;g 28-Feb-20: due date candidate PL commanding products for

validation;g From 10-Mar-20: start of swing-by approach navigation, special

pointings shall be minimised, weekly CPS delta-V slots;g 20-Mar-20: due date final PL commanding products;g 10-Apr-20: closest approach, accuracy of 2 days, to be consolidated

end 2019;g ESB + 1w: CPS delta-V slot;g 03-May-20: end daily ground station coverage;

Earth Swing-by


g Apr-20 (TBC): deadline for Payload / MMO Operations Requests;g May-Jun-20: consolidation of pointing timeline with PIs (lead FD);g Need for touch-up with SEP between ESB and VSB1 TBD,

expected to be small if needed;g From mid Sep-20: start of swing-by approach navigation, special

pointings shall be minimised, weekly CPS delta-V slots;g 15-Oct-20: closest approach;g VSB + 1w: CPS delta-V slot;g VSB + 1m: end daily ground station coverage;

Detailed Products submission deadlines will be communicated at the next SWT.

Venus Swingby 1

1st Venus flyby: detailsVenus flyby 1

Date 15-Oct-2020Closest Approach (km) 10681Electric propulsion end before CA N/A *

Electric propulsion start after CA N/A *

Sun distance (AU) 0.72Eclipse duration (mn) 0Occultation duration (mn) 0Sun-Earth-Probe angle (deg) 38Earth distance (AU) 1.17X-TM bit rate (kbps) 65.3

V

E


1st Venus flyby: attitude & constraints


MCS configuration

1st Venus flyby: attitude & constraints

• during cruise and outside electric propulsion, the defaultspacecraft composite attitude is +Y axis pointed to the Sun.

• spacecraft attitude is adjusted by ground around the sun linesuch that the angular momentum loading is minimized &ground contact maximized during ground station passes.

• the need for angular momentum load minimization can berelaxed for CA +/- 1 day

• general attitude constraints:I. at a Sun distance of 0.7 AU, the possible offset of the

Sun direction in the spacecraft composite +YZ plan is+27 to -9.1 degrees;

II. a roll phase around the Sun direction is also possible(360 degrees rotation).



Venus flybys: trajectory & magnetosphereXZ plan

For MPO: MAG, SERENA, SIXSFor Mio: MPPE, MGF, PWI

Venus flybys: trajectory & atmosphere


MERTIS, PHEBUS, MGNS

Russell et al., 2013

Venus flybys & deadlines

SWT BepiColombo – October 15th 2019 à To build a final timeline

Venus flybys & deadlines


à To build a final science matrix

Mid-IR Venus observations simultaneous close-up & distance observations

MERTIS, 7-14 µm• 15 October 2020 ~06:00 UT

– Close-up imaging over noon-to-afternoon low latitudes (southern) with the 4° FOVCon: Limited area can be observed (apparent size of Venus 35°)

– Spectral analysis for• mesospheric temperature profiles and

cloud top structures• SO2 abundance and scale heightVenera observations in 1983-1984 [Zasova et al. 2007]

LIR, 10 µm (8-12 µm) image• 15 October 2020

– Global view(apparent size of Venus 2°). Con: Low spatial resolution

– Accumulated data set, so temporal variability can be analyzed

– For coordinated observations:Prof. Taguchi (PI of LIR) offers• Possible to increase the

number of images to enhance SNR.

• Possible to make simultaneous imaging at the time of MERTIS’ observations.

Comparisons of MERTIS, LIR, and ground-based observations

MERTIS & LIR• MERTIS:

– ~50 min observations before the closest approach. Noon-to-afternoon low latitudes.Spectral information + high spatial resolution

• LIR: – 10-20 October 2020, except 18 October,

complimentary global view monitoring.– 18 October (see the figure below)

pericenter passage. Close-up around the morning terminator.

Ground-based observations• Examples:TEXES/IRTF (Therese et al. 2011-2019)COMICS/Subaru (Sato et al. 2014)MIRSI/IRTF (Peralta et al.)Other infrared observations, e.g. MILAHI at Haleakala, Hawaii (Tohoku univ., Japan)Other wavelength, e.g. ALMA, JCMT etc.

• Around the time 15 October 2020, >5 consecutive days– Overlapped & Complimentary observations,

depending on scientific objections.– Example1:SO2 plume (Therese et al. 2019)– Example2: Cloud top structures and the North-

South polar vortex link (Sato et al. 2014)– Example3: Thermal tide analysis using the

complimentary observations– Example4: Other spectral range, such as sub-mm

to UV, can be useful to compare temperature/winds (cloud morphology and Doppler shift) /trace gases’ abundances simultaneously

1st venus flybymid-ir venus observations simultaneous close-up & distance observations mertis,...

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