Different scenarios of the “Venera-D” mission KIAM Ballistic Center Team (Keldysh Institute Of Applied Mathematics RAS)

Grushevskii A.V. Golubev Yu.F., Koryanov V.V., Tuchin A.G., Tuchin D.A. Different scenarios of the “Venera-D” mission Venera SDT Meeting 6-7 October 2015 Moscow, Russia Keldysh Institute of Applied Mathematics Russian Academy of Sciences

1.Venus is very appealing not only for artists, but for leading Earth scientists Hesperus

3. Venusian missions are convenient and interesting on one's Jack and on the side for mission design The Vega program was a series of Venus missions that also took advantage of the appearance of Comet Halley in Vega 1 and Vega 2 were unmanned spacecraft launched in December They had a two-part mission to investigate Venus and also flyby Halley's Comet. VEGA

Booster Venusian Gravity Assists V - Venusian GAMs From Vouagers and “Cassini” to Jupiter Icy Moon Explorer (JUICE) and “Laplas-P” EVEE gravity assists – JUICE (2026) spacecraft to visit the Jovian system focused on studying three of Jupiter's Galilean moons VVEJ gravity assists – Cassini mission (1997) Cassini Cruise trajectory

Cranking Venus Gravity assists “Interhelio-Probe” Polar- Ecliptic Patrol probes on the Sun Solar Orbiter (“SolO”) are planned Sun-observing satellites, under development by the ESA and Russia. They are intended to perform detailed measurements of the inner heliosphere and perform close observations of the polar regions of the Sun “Pumping” E-Gravity Assists “Cranking” V-Gravity Assists Solar Orbiter

Gravity assists are very useful For the Venusian Orbiters and Landers delivery the decreasing of the spacecraft’s velocity relative Venus demanded. Not booster gravity assists!

Venusian missions Transited Orbital Landing Orbiters & Landers For “Red” scenarios Total Delta-V is very expensive (Boosting+Reducing) We can to exchange some reducing DeltaV on the Total time of flight with help of: Gravity Assists; Aerobracking; Ballistic Capture (Belbruno); High-Altitude GAMs (Ross, Sheress)

Hohmann strategy (very expensive)

Hohmann strategy (very expensive) (axes Ra-Rp in A.U. )

Hohmann strategy (very expensive)

Hohmann strategy (very expensive) (axes Ra-Rp in A.U. )

Standard scenarios The report presents the count results for launce windows on the time span from 2020 to There are deter-mined power characteristics of flights and selected optimal windows. There are given results of calculations for the Descent Module destination areas on the Venus surface. Various variants of the subsatellite separation from the base SC are considered. These variants are distinguished by orbit periods. And the question of the SC motion determination in the Venus artificial satellite orbit is considered as well. 14

15 Possible Launch windows and their Total Rates DepartureArrival Duration of the section, days V dep, km/с V arrival, km/с Total Velocity, km/с

16 Isolines of the Total velocity rate for the 2020 Launch window (“Porkchop Plots”) OX- Launch Data, OY – The Cruise Duration (days) Red Cross – an optimal data ( ) and the cruise duration (196 days)

TP-graphs reducing strategy

V -infinity reduction is a very specific problem I

Ti-Criterion (Tisserand’s Criterion) Restricted 3 Body Problem Jacobi Integral J  Tisserand’s Parameter Ti ( see R.Russell, S.Campagnola) “Isoinfine” (It’s mean ” Captivity ”)

II. Gravity Assists Maneuver (GAM)

T-P-graph for “Interhelio-Probe”

Tisserand-Poincare graph

Trajectories Beam Selection We need the criterion of bulk selection of encounters with V-infinity reduction Semi-code is “not_V” ^ “V” The “Full Conjunction Code” is: “Not_Venus” + ”Venus” + ”Venus” Or “E” ^ ”E” ^ …^ ”E” ^ ”V”

Real Beam searching (“Sheafs”) (axes Ra-Rp in RJ) Rebounds E^V millions modes Rebounds-ReRebounds E^V^V thousands modes

Using the TRAJECTORY BEAM method for Gravity Assists Sequences Determination

Bi-Tisserand graph The “moment of target-switch” determination

28 The Delivery of Lander-SC (CA) scheme

29 The surface of ballistic reachability for launch in y.2021 y.2023 y y y.

30 The area of ballistic reachability for lunch in OX-Latitude OY- Longitude of the landing point 2.OX- longitude Earth-Descent Module-Venus (red), Solar- Descent Module-Venus( blue)

31 Period’s variants of main SC and sub-satellite №Sub-SC’s period, hourMain SC’s period, hour

32 Var. 1 Orbit elements of the Venusian artifical satellite orbit ParameterValue Major semiaxis, km Eccentricity0.899 Inclination, deg90.0 The longitude of the ascending node, deg240.2 The argument of periapsis, deg334.4 Middle motion (n) Rad/1000*c Period, hours48.0 Periapsis, km Periapsis altitude, km Apoapsis, km Apoapsis altitude, km Lattitude of the landing point, deg– Longitude of the landing point, deg

Conclusions 1. For transit missions not all Venusian surface is available. Orbiters are demanded 2. High inclined or polar orbits near Venus 3. We can to exchange some reducing DeltaV on the total time of flight with help of: - Gravity Assists ; -Aerobracking; -Ballistic Capture 33

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