The INFN-LNF Space Climatic Facility for the LARES mission and the - PowerPoint PPT Presentation

The INFN-LNF Space Climatic Facility for the LARES mission and the ETRUSCO project Claudio Cantone (INFN-LNF) for the LARES and ETRUSCO Collaborations International Workshop on “ADVANCES IN PRECISION TESTS AND EXPERIMENTAL GRAVITATION IN SPACE” Florence, ITALY, 28-30, Sep. 2006

The LARES mission • LARES: see talk by PI, I. Ciufolini • Space climatic characterization • Laser ranging tests • LAGEOS I engineering proto from NASA • (LAGEOS spin measurement) ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 2 C. Cantone (INFN-LNF)

LAGEOS 3x3 matrix and LARES 1:2 proto built at LNF IR images ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 3 C. Cantone (INFN-LNF)

Simulation of τ CCR (thermal relaxation time) CCR T(K) NEVER measured. Computations vary by 300%. Goal: measure τ CCR at ≤ 10% LAGEOS accuracy . This will make the matrix error on Lense-Thirring due to SUN=on, IR=off thermal thrusts negligible (permil level) τ CCR = 2400 ± 40 sec (2% error) σ (T) = 0.5 K t(sec) T = 276 K FEM model (250 nodes) at t = 2800 sec T = 278 K ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 4 C. Cantone (INFN-LNF)

LAGEOS sw model of thermal thrusts Steady state t=0 sec SUN=ON SUN=OFF for 4500 s then SUN=ON. IR always ON ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 5 C. Cantone (INFN-LNF)

Measurement of IR ε , ρ with IR camera LAGEOS IR pictures of the LAGEOS array matrix Indoor, in-air measurement at room temperature – Q camera = Q emission + Q reflected – T 4 camera = ε IR T 4 x + ρ IR T 4 bkg – ε IR (x) + ρ IR (x) = 1 – T x w/thermocouple – T bkg : black disk with controlled temperature = 10 o C or 50 o C Black disk At 10 or 50 ε IR (CCR) ~ 0.82 emissivity o ρ IR (CCR) ~ 0.18 C Ø = 10 cm reflectivity ε IR (Al) ~ 0.15 ρ IR (Al) ~ 0.85 LAGEOS array ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 6 C. Cantone (INFN-LNF)

INFN-LNF Space Climatic Facility Thermal shield (77 K) Service turret IR camera L=2 m, ∅ = 1 m Vacuum shell Ge window Ø=10 cm LARES proto Ø = 30 cm T = 77 K P ≤ 10 -5 mbar Earth IR simulator (Z306 paint) Solar beam Solar NEO shroud Quartz window simulator Ø = 30 cm Ø = 40 cm T = 250 K (alodized back)

Inside the LNF SCF Side tunnel for IR Service camera turret Support for GNSS array... Support for … or Earth IR disk spherical simulator test-mass ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 8 C. Cantone (INFN-LNF)

SCF commissioning complete T = 77 K, P = 2 x 10 -6 mbar Sun simulator tested in August, Earth IR simulator tested in Sep. Thermogram of the LAGEOS array inside SCF in August ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 9 C. Cantone (INFN-LNF)

Earth IR simulator Al disk painted with Z306 kept at 254 K by Thermo Electric Coolers (TECs) ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 10 C. Cantone (INFN-LNF)

Solar simulator BEAM RADIATION LOSS SPLITTER, only ~ 10% FILTERS “AM0” SPECTRUM IR (1 sun in NEO) 1 SUN 1366.1 W/m 2 12kW QUARTZ VIS (Tungsten filament) HALOGEN LAMP 6kW UV METAL HALIDE ARC LAMP ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 11 C. Cantone (INFN-LNF)

Solar simulator • Acceptance test at TS-Space (UK) in June • Delivered to LNF on July 12 • Final calibration at LNF end of July ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 12 C. Cantone (INFN-LNF)

Measured Solar Simulator spectrum and uniformity • “AM0” standard spectrum (400-3000 nm) • Absolute calibration @1% w/Solarimeter • HV adjusted for lamp ageing w/PIN diode Relative Intensity Uniformity Spectrum 35 cm diameter AM0 Wavelength (300-1800 nm) + 1.5% - 1.5% ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 13 C. Cantone (INFN-LNF)

Optical characterization of CCRs at LNF Test 1: Far-Field Diffraction Pattern (FFDP) of single CCR return with CW laser • “Optical FLAT” (mirror) for normalization • 2 CCDs as laser beam LNF LNF optical optical bench bench is is courtesy of courtesy of G. G. Giordano Giordano profilers. PC DAQ, firewire interface, commercial sw. Repeat test inside the SCF Thanks to John Degnan, Dave Arnold, Erricos Pavlis (ILRS), Jan McGarry (NASA-GSFC) for advise and to Doug Currie (Univ. of Maryland) for help on setting up the optical tests at LNF ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 14 C. Cantone (INFN-LNF)

Faraday Pol. 2 Pol. 1 Rotator Laser 6.1 mW Mirror 1 405 µ W 450 µ W 500 µ W 6.9 mW 400 µ W Object. 1 45° 45° 0° OPTICAL CIRCUIT FOR FFDP TEST Lens 1 360 µ W − = 3 2 a 0 . 5 10 a 10 − a 0 . 5 − − − = × = Beam 25 nW 0.25 nW 0.125 nW Splitter 52 µ W 48 µ W 280 µ W CCD Camera 75 µ W Flat Mirror Lens 2 Object. 2 Filter 1 Filter 2 Filter 3 readout via FW by PC or CCR

He-Ne laser beam readout by CCD Laser profiles in varying conditions to test CCD dynamic range and laser beam attenuation needed to avoid CCD damage. Testing also sw functionality. Now: perform optical circuit alignment. Next: take FFDPs ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 16 C. Cantone (INFN-LNF)

LAGEOS I prototype sent by NASA-GSFC to LNF Engineering model property of NASA-GSFC to LNF for test in the SCF 40 40 cm cm outer outer Al Al diameter. diameter. 37 37 original original CCRs CCRs, , of of good good Laser-optical quality Laser-optical quality ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 17 C. Cantone (INFN-LNF)

FEM model of the NASA LAGEOS I “sector” CCRs and mounting Al and CCR FEM mesh, front view Rings, back view ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 18 C. Cantone (INFN-LNF)

The NASA LAGEOS I “sector” inside the SCF The CCR outer diameter is 34 cm and the sun beam is 35 cm: Perfect match ! ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 19 C. Cantone (INFN-LNF)

Measurement of spin • Measurements of spin direction and rate at UMCP • LOSSAM (LageOS Spin Axis Model): based on past measurements predicts future direction and rate (DELF+UMCP) • SW revived and now run by R: Taurasat LNF ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 20 C. Cantone (INFN-LNF)

The INFN ETRUSCO project • The SCF was funded with a small contribute of the INFN Astroparticle Committee and by the LNF Director. We used heavily existing LNF resources • The Director asked us to use it for LARES and, possibly, find other projects of space physics and technology to maximize the output ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 21 C. Cantone (INFN-LNF)

Extra Terrestrial Ranging to Unified Satellite COnstellations “Extra Terrestrial Ranging”: measurement of satellite space- time coordinates with optical e.m. waves (laser ranging) “Unified Satellite COnstellations”: addition of LASER ranging to standard MICROWAVE ranging Foreign Collaborations Foreign Collaborations INFN-LNF Group - Intern. Laser Ranging Service(ILRS) R. Vittori (ESA, Italian Air Force) M. Pearlman, E. C. Pavlis S. Dell’Agnello (LNF) - Resp. - NASA-GSFC J. McGarry, T. Zagwodski, G. Delle Monache (LNF) D. Arnold C. Cantone (LNF) M. Garattini (LNF) - Univ. Maryland, College Park A. Boni, LNF (LNF) D. G. Currie, C. Alley M. Martini (LNF) - S. Turyshev (NASA-JPL) G. Bellettini (Univ. Rome Tor Vergata) - Sigma Space Corporation, J. Degnan R. Tauraso (Univ. Rome Tor Vergata)

ETRUSCO projects • Improving future GNSS in Near Earth Orbits – Integration of laser and MW ranging on GALILEO (EU) – Better understand laser ranging on GALILEO and GPS-2, then push for its integration on GPS-3 (US) – Map NEO space-time with 30 satellites to test accurately GR corrections • Proposed Deep Space Gravity Probe mission – Develop test-masses to study 1/r 2 in the outer solar system (the “Pioneer anomaly”) and test them in the SCF • Largest thermal accelerations for NEO test masses (LAGEOS and LARES) are 10 times smaller than the Pioneer anomalous deceleration ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 23 C. Cantone (INFN-LNF)

GNSS Unified Constellation MW Ranging: standard measurement of (space-)time coordinates of the “GPS” satellite with microwaves. σ ~ 10-20 cm. No long term memory (periodic clock re-synchronization), but great for real-time navigation LASER Ranging : σ ~ few mm (with complete climatic & optical characterization), absolute position wrt ITRF, long term stability (tens of yrs) Prototype of Prototype of the the 30 30 GALILEO GALILEO satellites satellites ( ≥ 2008) 2008) Standard MW emitters 100 Retro reflectors MW RANGING LASER RANGING ”Exper. Gravitation in Space”, Florence, Sep. 30, 2006 24 C. Cantone (INFN-LNF)

Current GNSS solid retroreflector retroreflector arrays arrays Current GNSS solid V. Vasiliev, IPIE-Moscow; talk at FPS-06, Frascati, March 06 (see http://www.lnf.infn.it/conference/fps06/ ) GALILEO TEST satellites GALILEO TEST satellites Orbit: h = 23200 km, i = 56 ° Orbit: h = 23200 km, i = 56 GPS-35 Orbit: h = 20200 km, i = 54 ° GPS-35 Orbit: h = 20200 km, i = 54 GPS-36 Number of CCR CCR’ ’s s: 32 : 32 GPS-36 Number of GIOVE-A (76 GIOVE-A (76 CCRs CCRs) GIOVE-B (67 ) GIOVE-B (67 CCRs CCRs) )