The Potential Use of the LTMPF for Fundamental Physics Studies on the ISS Talso Chui Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California NASA ISS Workshop on Fundamental Physics Dana Point, California October 13-15, 2010

The Low Temperature Microgravity Physics Facility (LTMPF) PM: J. Pensinger DPM: F. C. Liu  LTMPF  A multiple-user Facility for scientific research requiring both microgravity and low temperature conditions

Why Low Temperature? n Low Thermal Noise  low noise devices. n Superconductivity  sensitive instrumentation. – Superconducting Quantum Interference Device (SQUID). – Ideal Magnetic Shield. n Superfluid Helium. – Very sharp transition. – Ideal model system for phase transition studies. – Very high thermal conductivity.

Why Microgravity? n Uniform sample for phase transition studies. n Free falling test mass for gravitation studies. – Only possible for short time in drop towers on Earth. – Can be approximated by suspension in direction of g. o Need strong spring on Earth. o Only very weak spring is need on ISS. n Larger velocity modulation for relativity tests. – Velocity vector reverse once a day on Earth, once every 90 minutes on orbit.

Heritage n Superfluid Helium Experiment (1985). PI: Peter Mason, JPL – Demonstrated containment of superfluid in space. n Lambda Point Experiment (1992). PI: John Lipa, Stanford U. – Confirmed theory to near K of phase transition. – First time SQUID was flown. – High Resolution Thermometer: 0.26 nK-Hz -1/2 noise. n Confined Helium Experiment. PI: John Lipa, Stanford U. – Tested phase transition under confinement. – Helium confined in 57-μm planar geometry

Justification for Microgravity n Sharp superfluid helium transition Lipa et al., PRL 76, 944 (1996). Space Ground

Justification for Low Temp. Lower noise Sensitive SQUID technology High Resolution Thermometer Day et. al, JLTP, 107, 359 (1997).

LTMPF Payload Overview Mass: 600 Kg Volume: 82 x 185 x 104 cm Cryogen life: 4.5 months on orbit Power Dissipation: 350 W 2 Cold Instrument Inserts: 15 Kg each. Payload Bay Access: L-64 hrs. Shielded Magnetic Field: 10 mGauss Dewar Temperature: 1.5 K. # SQUID available: 12 (~6 per user) Communication Downlink: 0.2 Mbps Communication Uplink: 0.01 Mbps.

LTMPF Payload Overview PIU for interface to ISS FRAM for interface to carrier Grapple Fixture for robotic transfer from carrier to ISS

LTMPF Payload Overview

Helium Tank Overview

Cryo-Insert Overview

Probe Description

Optional 2-stage configuration for experiments that need more space.

Magnetic Shields

Charcoal Adsorption Pump

LTMPF Current Status  Major components fabricated.  Stored in Flight Certified area in Bldg 79 JPL.  All key staff at JPL are still employed on other projects. – Available on short notice. Struts

LTMPF Current Status  Major EM Electronic Boards Fabricated and Tested.

LTMPF Current Status  All the certification records and analysis reports have been maintained.

Experiments Lined Up to use LTMPF n DYNAMX/CQPI: R. Duncan / D. Goodstein n MISTE/COEXPI: M. Barmatz / I. Hahn n SUMOPI: J. Lipa n ISLEPI: H. Paik n EXACTPI: M. Larson/N. Mulders n BESTPI: G. Ahlers/F. C. Liu n SUEPI: J. Lipa

Experiments Along Coexistence Near Tricriticality (EXACT) n Perform an experimental test of the exact predictions of the theory of phase transitions near the tricritical point of 3He-4He mixtures. n Second sound measurements with bolometer. n Microgravity justification: Mixture stratifies in gravity.

Superfluid Universality Experiment (SUE) n Measure superfluid density in pure Helium by second sound method at different pressures. n Test universality of exponents. n Microgravity justification: Sample non-uniformity in gravity.

Boundary Effects in Superfluid Transition (BEST) n Measure Thermal Conductivity in Confined Geometry at different pressures. n Test dynamic finite-size scaling theory. n Microgravity justification: Sample non-uniformity in gravity.

Conclusion n Many interesting and important physics experiments can be performed on the ISS if low temperature environment is provided. n LTMPF and similar follow-ons can provide this environment. n A new generation of students, scientists, engineers and managers are ready to carry on the torch.