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LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 1
A Low-Cost Mission for LISA
Markus Landgraf, Florian Renk, Pierre Joachim, Rüdiger Jehn
HSO-GFA
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 2
Overview
Basic working assumptions
Operational orbit: heliocentric slow drift-away
Soyuz launch from Kourou
Transfer scenarios
Total delta-v budgets
Conclusion
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 3
Basic assumptions
V-config
L=106km
basic angle 90deg, no difference in delta-v for 60deg
LISA | Kick-Off June 15th, 2011| CDF | HSO-GFA | Page 4
Circular Heliocentric Trailing
For slow drift (15deg over 5 years) “Stop” manoeuvre is required
Initial trailing angle 10deg to avoid disturbance of the formation
Third body perturbation by the Earth is compensated by drift in the HCW frame
Full numerical simulation and minimisation of breathing performed
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 5
Drifting
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 6
Constellation Breathing
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 7
Constellation Arm Length
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 8
Constellation Range Rate
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 9
Interplanetary Transfer
vinf [m/s] decl [deg] rasc [deg] Δvarr [m/s] mother 162 11 +25 154 daugther1 329 +26 -7 130 daughter2 274 -26 +19 104
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 10
Soyuz Launch from Kourou
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 11
Soyuz Launcher Performance
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 12
Transfer Scenarios
Baseline: Double launch lunar fly-by • 1. Soyuz launches 2 Daughters into HEO at 15deg
inclination
• Daughters perform lunar fly-by to reach escape condition
• 2. Soyuz launches Mother directly into i=65deg departure hyperbola
Option 1: Double launch direct: same launch scenario as in baseline, but without lunar fly-by, but split manoeuvres are performed after leaving the Earth’s sphere of influence
Option 2: Single launch direct: launch all spacecraft on one launcher, all three perform a split manoeuvre after leaving the Earth’s sphere of influence
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 13 LISA Study
Lunar Fly-by transfer
Example transfer: • Injection of S/Cs into HEO with rapo = 400,000 km
- Orbital plane is equivalent to lunar orbital plane (LOP) (accessibility from Kourou TBD, see next slide)
• At apogee both S/C change the inclination with respect to the LOP by 10.5 DEG (both planes are then 21 DEG apart)
• At next perigee pass the apogee must be raised to reach the required v∞ after the fly-by - Apogee raising ΔV = 40 m/s
• Lunar fly-by approaching the moon from different hemispheres leads to required v∞ vectors
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 14 LISA Study
Lunar Fly-by transfer
Insertion in lunar orbital plane (LOP) not always possible • Restrictions on the launcher inclination due to walking
impact point of 3rd stage GAIA launcher scenario with 15 DEG parking orbit
• Unbalanced ΔV for rotation of orbital planes - Required rotation now 3 DEG and 24 DEG
• Manoeuvre 11 and 80 m/s, respectively
Declination of the moon is 50 % of the time below 15 deg and can then be reached from a 15-deg inclination HEO
• Lunar flyby time slot from MJD=7153.5 to 7159.5 • Example case: flyby on 8 Aug 2019 (7159.07) with
v∞=731 m/s at an altitude of 200 km
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 15
Delta-v budget LGA transfer, double launch
mother daughter 1 daughter 2 launcher disp 36m/s 5m/s 5m/s perigee raise - 40m/s 40m/s
plane change - 11m/s 80m/s apogee raise - 40m/s 40m/s arrival 154m/s 130m/s 104m/s navigation 20m/s 20m/s 20m/s launch window reserve, gravity loss (20%)
42m/s 46m/s 50m/s
total 252m/s 272m/s 299m/s
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 16
Delta-v budget direct transfer, double launch
mother daughter 1 daughter 2 launcher disp 36m/s 5m/s 5m/s perigee raise - 10m/s 10m/s
apogee raise - 773m/s 773m/s split - 148m/s 148m/s arrival 154m/s 130m/s 104m/s navigation 20m/s 20m/s 20m/s launch window reserve, gravity loss (20%)
42m/s 218m/s 212m/s
total 252m/s 1304m/s 1272m/s
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 17
Delta-v budget direct transfer, single launch
mother daughter 1 daughter 2 launcher disp 5m/s 5m/s 5m/s perigee raise 10m/s 10m/s 10m/s
apogee raise 773m/s 773m/s 773m/s split 167m/s 167m/s 167m/s arrival 154m/s 130m/s 104m/s navigation 20m/s 20m/s 20m/s launch window reserve, gravity loss (20%)
226m/s 218m/s 212m/s
total 1355m/s 1304m/s 1272m/s
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 18
Consequences of Longer Arms
Cost is 100m/s per 1 million km in arrival delta-v, distribution between individual S/C is TBD
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 19
Conclusion (1/2)
The heliocentric drift-away formation has the potential to minimise the LISA propulsion system (in size, minimum thrust, and cost) other options do not provide the required formation stability, require significant station-keeping or large distances in the Earth
Increasing the arm length costs approximately 100m/s per 1 million km
Soyuz provides 1,933kg for the mother launch (i=65deg escape), 2,210kg (15deg HEO with apogee at 400,000km, 2,277kg minus 3% margin due to unconfirmed launcher optimisation)
LISA | Internal Final Presentation July 8th, 2011| CDF | HSO-GFA | Page 20
Conclusion (2/2)
Delta-v budget provided for three transfer scearios • double-launch with daughters performing lunar fly-by
• double-launch with direct transfer
• single launch with direct transfer