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Third International ASTROD Symposium, Beijing 14 July 2006. LISA Pathfinder. A Technology Demonstrator for the LISA Space Gravitational-Wave Detector Gerhard Heinzel and Albrecht Rüdiger , AEI Hannover. Thanks. - PowerPoint PPT Presentation
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LISA Pathfinder
A Technology Demonstrator for the
LISA Space Gravitational-Wave Detector
Gerhard Heinzel and Albrecht Rüdiger, AEI Hannover
Third International ASTROD Symposium, Beijing14 July 2006
LISA Pathfinder
6th International LISA Symposium
Thanks
First I would like to convey Gerhard Heinzel‘s regret that he cannot be here today: urgent other commitments
My talk will draw to a major extent on Gerhard’s notes
Next, I would like to express my thanks for the invitation to come to Beijing for this
Third International and First Sino-German ASTROD Symposium,
this one again in Beijing as the memorable first one in 2001
It fills me with joy to meet many „old“ friends and colleagues, and to make new acquaintances, and I am again overwhelmed by the friendliness and helpfulness of the organizers
LISA Pathfinder
6th International LISA Symposium
Sequence of talks on LISA, LISA Pathfinder
It is unfortunate that my talk on the LISA Pathfinder precedes Oliver Jennrich‘s talk on LISA, to be held tomorrow
May I, not to overload my talk with the details of LISA, just assume LISA to be sufficiently known to most of us and plunge into discussing its Technology Demonstrator
Tomorrow will then give you the latest news on LISA, from the person most competent on it: Oliver Jennrich
LISA Pathfinder
An ESA-Nasa project to test certain technological aspects of
the full-sized LISA GW detector:
Third International ASTROD Symposium, Beijing14 July 2006
LISA Pathfinder
An ESA-Nasa project to test certain technological aspects of
the full-sized LISA GW detector:
Two free-floating test masses in one spacecraft
Third International ASTROD Symposium, Beijing14 July 2006
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
Interferometry on LISA Pathfinder: two free-floating test masses
Multiple interferometry using heterodyne Mach-Zehnder to measure: relative distance, displacement, relative beam phase, laser frequency
LISA Pathfinder
6th International LISA Symposium
Injection into orbit near L1 Lagrange pointwith sequence of apogee-raising rocket firings
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
After initial study, SMART-2 was descoped and renamed LISA Pathfinder– Darwin Pathfinder removed from mission– Single spacecraft with two payloads:
• European provided LTP • NASA provided DRS
– Both payloads comprised*:• Two inertial sensors• Laser metrology• Micro-Newton Thrusters• DFACS
– Orbit: Lissajous orbit around L1– Launch Vehicle: Rockot– Launch date: 4th Qtr 2009
*The inertial sensor and laser metrology have now been descoped from the DRS
LISA Pathfinder
6th International LISA Symposium
Mission Goal [1]
The primary goal of LISA Pathfinder is to verify that a test mass can be put in pure gravitational free-fall with residual acceleration noise less than
over a frequency range
of 1-30mHz
HzmsmHz
ffSa
2
2
1421
31103
LISA Pathfinder
6th International LISA Symposium
Mission Goal [2]
A secondary goal, which has now become directly relevant to LISA, is to demonstrate laser metrology using free floating mirrors with a displacement sensitivity of
over a frequency range of 1-30mHz
Hzmf
mHzS x
2
1221 3
1109
LISA Pathfinder
6th International LISA Symposium
Proof Mass
Procured from Heraeus, Germany46mm cube of Gold-Platinum– 73% Au:27%Pt
Mass = 1.96kgIndentation on top and chamfered corners for caging mechanism
Similar to LISA test mass– Magnetic Susceptibility requirement
relaxed by one order of magnitude
“A sensitive Torsion Balance for LISA Proof Mass Testing”, Stephen Schlamminger, Tuesday, 16:50
RawMaterial
Polished
Polished and Coated
LISA Pathfinder
6th International LISA Symposium
Inertial Sensor Ground Testing
Inertial sensor cannot be fully tested on ground– Hence the need for LISA Pathfinder
Ground testing focussed on torsion pendulums
Dedicated torsion pendulums constructed at the University of Trento
Noise in torsion pendulum approaching that of LISA Pathfinder!!– Only in one axis– Light-weighted proof mass– Cannot fully represent cross-coupling
LISA Pathfinder
6th International LISA Symposium
Micro-Newton Thrusters
Micro-Newton thrusters for LTP based on Field Emission Electric Propulsion (FEEP)
Two developments underway in Europe– ALTA: Caesium FEEP– ARCS: Indium FEEP
After first phase of development, down-select will be made between the two thruster architectures– This design will be taken to flight hardware
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LTP Integration: how it’s put together
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LTP Core Assembly
LISA Pathfinder
6th International LISA Symposium
Schütteltest Optische Bank
LISA Pathfinder
6th International LISA Symposium
Launch Vehicle
Baseline launch vehicle: Rockot– Procured from Eurockot, Bremen– Breeze KM upper stage– Proven vehicle with heritage
• SS19 ICBM!
– Launch from Plesetsk, Russia (latitude 63o)– Injection into 200x900 km orbit– Max lift-off weight of S/C: 1910 kg– Facility to be upgraded for bi-propellant
fuelling (vapour traps, waste disposal, etc)
LISA Pathfinder
6th International LISA Symposium
Launch Vehicle
Target launch vehicle is VEGA– Procured from Arianespace– New launcher
• LPF could be first flight!
– Launch from Kourou, French Guiana (latitude 5o)– Injection into circular orbit…Check– No free injection into L1 Lissajous orbit
• Requires injection burn
– Winter temperature : ~28oC
LISA Pathfinder
6th International LISA Symposium
Launch Sites
Plesetsk:
Winter temperature : -30oC!
Kourou:
Winter temperature : +28oC!
LISA Pathfinder
6th International LISA Symposium
Orbit
LPF launched into high inclination orbit of 200x900km
15 apogee raising manoeuvers required to deliver LPF to L1– High inclination orbit allows free transfer (no orbit insertion required)
Prop module separate during transfer phase
Final orbit is Lissajous orbit around L1
LISA Pathfinder
6th International LISA Symposium
Interferometry on LISA Pathfinder: two free-floating test masses
Multiple interferometry to measure: relative distance, displacement from OB, relative beam phase, laser frequency
LISA Pathfinder
6th International LISA Symposium
Heterodyne measurement of relative distance
LISA Pathfinder
6th International LISA Symposium
Displacement with respect to optical bench
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
Interferometry on LISA Pathfinder: two free-floating test masses
Multiple interferometry to measure: relative distance, displacement from OB, relative beam phase, laser frequency
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
Optical Bench EM performance
LISA Pathfinder
6th International LISA Symposium
Phase-meter performance
LISA Pathfinder
6th International LISA Symposium
LISA Pathfinder
6th International LISA Symposium
LPF Status
LPF passed Mission Preliminary Design Review (M-PDR) in February 2006– M-PDR consolidates the LTP PDR, System PDR, Ground
Segment Requirements Review, and DRS CDR
LISA Pathfinder is now in PHASE C/D: Detailed Design Phase
LISA Pathfinder
6th International LISA Symposium
LPF Main Reviews/ScheduleSystem Requirements Review Jun-Nov 2004
Technology Readiness Review 22 June 2005
Preliminary Design Review 29 September 2005
LTP Preliminary Design Review 31 August 2005
Ground Segment Req Review 24 November 2005
DRS Delta-CDR/Risk Review 20 January 2006
Mission Preliminary Design Review 16 February 2006
LTP Subsys. Critical Design Review Q3-Q4 2006
LTP Critical Design Review Q1-Q2 2007
Critical Design Review Q3 2007
Flight Acceptance Review Q4 2009
Launch Q4 2009
LISA Pathfinder
6th International LISA Symposium
LTP Team
LTP workshop, Trento 2005
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