Fundamental Physics Program onboard Space Shuttle and Planned for International Space Station

Mark C. LeeNASA Exploration Systems Mission Directorate

Fundamental Physics Program at NASA

• Physics And Chemistry Experiments (PACE)

• Fundamental Physics Experiments and PACE onboard Spacelab/STS

• Fundamental Physics Investigations Planned for ISS

15 Physics And Chemistry Experiments (PACE)

PACE…

Timeline

• Five Contemporary Fundamental Physics NRAs for Spacelabs and ISS – 1994/1996/2000/2001/2002

• FP, PACE and Other Experiments Executed onboard Spacelab/STS– LPE/CHeX/ZENO/CVX;– DDM/DPM/STDCE;– AADSF/CGF;IDGE;– SSCE/DCE;PHaSE

• Four Microgravity Sciences Disciplines– Fluids/Materials/Combustion/Biotechnology– Fundamental Physics?

David Lee – Delivery from Heaven

Timeline continues…

• Formation of FP Discipline Working Group – late 1996

• Publication of Fundamental Physics in Space Roadmap (Led by Ulf Israelsson)

William Phillips – More from…

Delivery of Confined Helium Experiment (CHeX)

Wolfgang Ketterle – and More and More…

Timeline continues…

• 71 Distinguished FP Principal Investigators as of July 12, 2002, including 10 ISS Flight Investigations

• But…

• No resolution to the originally Selected PACE Program Satellite Test of Equivalence Principle (STEP)

Satellite Test of Equivalence Principle (STEP)

US$28M Pre-Phase A

External Peer-Review Recommendations on STEP

1983 - Selected by Physics and Chemistry Experiments (PACE) Panel

1988 - Reviewed by Space Study Board of National Research Council in SPACE SCIENCE IN THE TWENTY-FIRST CENTURY: IMPERATIVES FOR THE DECADES 1995 TO 2015 for FUNDAMENTAL PHYSICS AND CHEMISTRY.

1990 - Reviewed by NASA’s ad hoc Committee on Gravitation Physics and Astronomy (Chair: I. Shapiro). The Committee strongly urged NASA continuing funding of laboratory engineering development of STEP in the next three years.

1990 - Assessment by an ESA ad hoc Committee on Fundamental Physics and Experiments in Space (Chair: F. Fuligni). STEP was ranked the highest priority among five proposals for fundamental physics experiments in space submitted in response to ESA’s M2 Mission announcement.

1993 - Assessment of the ESA ad hoc Fundamental Physics Working Group (Chair: J. Blaser). STEP was ranked number one priority out of 16 proposals for fundamental physics submitted in response to ESA’s M3 Mission announcement.

1994 - Reviewed by NASA QuickSTEP ad hoc Science Review Committee (Chair: Clifford Will). The Committee reported that “...STEP significantly strengthening the foundation of general relativity... and ... is technologically feasible, with only modest improvements from current technology needed.”

1996 - Comparatively reviewed of NASA’s MiniSTEP, CNES’s GEOSTEP and ASI’s GG by ESA Fundamental Physics Advisory Group (FPAG) (Chair: M. Jacob). FPAG strongly recommended MiniSTEP over the other two candidate experiments as “the scientifically most important mission in fundamental physics.”

Recruiting Joseph Taylor

Blue Ribbon Peer-Review Panel on STEP

1998 - NRA-96-HEDS-03 Blue Ribbon Peer-Review Panel on the FP Proposals: “The panel strongly and unanimously recommends this experiment (STEP) for flight development”.

Blue Ribbon Panel Member

Joseph Taylor – ChairRobert RichardsonThibault DamourKip ThorneEric AdelbergerRiley Newman

Microgravity Fundamental Physics Program were reviewed twice in person by Mr. Daniel Goldin, the NASA Administrator

1.1998 - With Joseph Taylor, Thibault Damour, Arnauld Nicogossian and Mark Lee

2.2001 - With NASA Chief Scientist Kathie Olsen and Mark Lee – leading to an article intended for Physics Today

NASA Administrator’s review

Mr. Goldin’s Physics Today’s Article

The Laboratory of Space: Fundamental Physics Research at NASADaniel S. Goldin and Nicholas Bigelow**

Daniel S. Goldin is the Administrator, National Aeronautics and Space Administration.

** Nicholas Bigelow is Lee A. DuBridge Professor of Physics at the University of Rochester and the Chairperson of NASA's

Fundamental Physics Discipline Working Group.

Submitted to Physics Today prior to November 17, 2001Declined due to his resignation as NASA’s Administrator

LTMPF is a state-of-the-art facility for long-duration science investigations whose objectives can only be achieved in microgravity & at low temperature

• First launch scheduled for November 2005

• External site on ISS’s JEM-EF• STS launch & retrieval • 2 Cryo Inserts; multiple experiments• Cryogen lifetime ~ 5 months• Environments monitored• Extensive inheritance• Operating lifetime: 5 missions• Teaming between Ball, Design_Net, Low-Temperature science community, & JPL

LTMPF Common - Facility

Impact:The results will provide conclusive experimental tests of the most advanced existing theories describing dynamical phase changes. These results will impact the understanding of dynamical critical phenomena, quantum liquids, quantum phase fluctuations, and closely related fields such as cosmology and quantum statistics.

DYNAMX

How do out-of-equilibrium conditions modify the nature of continuous phase transitions?--- Provide a bridge between theory and real systems

How: A new type of exceptionally stable high-resolution thermometers will be used to measure the thermal profile near the normal to superfluid interface while a small heat flux Q travels through the helium. The superfluid interface will be advanced slowly though the cell, and the temperature profile behind the interface will be recorded by three temperature probes imbedded in the sample cell’s side walls.

Figure Caption

Why:The superfluid transition in 4He has been the model system for testing the fundamental theory of phase transition. When driven away from equilibrium, the superfluid transition evolves from a simple critical point into a fascinating and complex nonlinear region, where the onset of macroscopic quantum order is masked by Earth’s gravity.

Peter K. Day, William A. Moeur, Steven S.McCready, Dmitri A. Sergatskov, Feng-Chuan Liu, and Robert V. Duncan, Phys. Rev. Lett. 81, 2474, 1998.RV Duncan, AV Babkin, DA Sergatskov, STP Boyd, TD McCarson, PK Day, J. Low Temp. Phys. 121, 643, 2000.

Robert Duncan, University of New Mexico

Final Peer Review Date: 1999 FHA: May, 2005FP2

Cell

Coolingstage

High resolutionThermometers

A bold attempt to explore a new area of critical phenomena, the study of non-equilibrium dynamics near criticality.

MISTE

Why MISTE in Space? --- Advance understanding of critical phenomena

Prototype MISTE flight cell

Impact:These results can be used to self-consistently test theoretical equation-of-state predictions for universal critical amplitude ratios and relations between critical exponents. These asymptotic and crossover models apply to all simple fluids and fluid mixtures and their unambiguous validation (or modification) will provide a major advancement in condensed matter physics and engineering.

How: The MISTE flight experiment will be performed on the LTMPF/ISS during a 4.5 month period. This study will conduct high precision pressure, density and temperature measurements as well as heat capacity at constant volume and compressibility measurements throughout the critical region of Helium-3. Measurements will specifically be performed along the paths of constant critical density, constant critical temperature and coexistence curve.

The need for a long-duration low-temperature environment in microgravity is particularly compelling for MISTE.

Martin Barmatz, Jet Propulsion Laboratory

Final Peer Review Date: 1999 FHA: May, May, 2005FP 3

Why:The most precise theoretical calculations of critical behavior are for a liquid-gas critical point. The huge compressibility associated with the earth’s gravitational field limits measurements in near-critical fluids. This difficulty can only be overcome by performing critical-point measurements in a microgravity environment.

Impact:The discovery of an infinitely large heat capacity always has a dramatic, transforming effect in physics. Just such an effect has been predicted theoretically in the conditions of the CQ experiment. The theory cannot be tested in the laboratory, but verification might be possible in gravity-free conditions. CQ will be a no hardware or engineering cost extension of the DYNAMX experiment.

CQ

Why measure CQ in space? ---Expand understanding of non-equilibrium systemsHow: Precision measurements of the heat capacity of helium will be taken just below the helium superfluid - normal fluid transition by applying small pulses of heat while a constant heat is passed through the DYNAMX thermal conductivity cell. The temperature rise caused by the heat pulses will be measured by the three temperature probes imbedded in the sample cell’s side walls.

CQ was selected from the OBPR-00 NRA

Weichman, Harter and Goodstein, Rev. Mod. Phys. 73, 1, 2001.

David Goodstein, California Institute of Technology

Why:The CQ experiment will extend the DYNAMX experiment into the Superfluid Phase, where a measurement of the heat capacity at constant Q (CQ) should answer the most important scientific issues in that regime.

Final Peer Review Date: 2002 FHA: May, 2005FP 4

Ground experimental results showing the enhancement in the heat capacity with applied heat current compared to theory and zero heat flow.

Impact:We shall test the scaling hypothesis and equation-of-state model predictions with unprecedented accuracy by combining with the data from MISTE experiment. Space cryogenic sensors (temperature, density, pressure) and flight software technologies shall significantly benefit other fundamental physics experiments.

COEX

Why COEX in microgravity? --- Advance understanding of phase transition

How: LTMPF/ISS and MISTE hardware are used to obtain the coexistence curve of helium-3 fluid near the liquid-gas critical point in microgravity condition. The density of the sample is manipulated in-situ low temperature gas handling system. The temperature is measured by the high-resolution thermometer. The coexistence boundary will be determined by detecting the specific heat anomaly at the transition temperature at different densities throughout the critical region.

The MISTE hardware that will be used for the COEX measurements.

COEX was selected from the OBPR-00 NRA

Why:Experimental studies of phase transition near the liquid-gas critical point has been severely affected by gravity. The confirmation and test of fundamental relationship between critical exponents and amplitudes is difficult unless experimental quantities are simultaneously obtained in a same measurement condition.

Inseob Hahn, Jet Propulsion Laboratory

Final Peer Review Date: 2002 FHA: May, 2005FP5

Impact:Provides new tests of three basic theories of physics: Special Relativity, General Relativity, and the Standard Model of matter. Also, interconnection with ISS atomic clock experiment RACE improves both science and atomic clock performance.

SUMO

Why a Superconducting Oscillator in Space? --- Test Special and General Relativity How: SUMO is developing a new generation of superconducting microwave cavities that are much less sensitive to acceleration than earlier models. Two superconducting cavities will be mounted at right angles to each other for Special Relativity tests, and comparison with an atomic clock gives additional tests of Special and General Relativity. Dependence of the frequencies on orientation and orbital velocity vector of ISS will lead to tests of deviations from the Standard Model of matter.

Superconducting cavity design for reduced acceleration sensitivity

SUMO will be a landmark experiment. It will not only allow scientists to test the fundamental theories of physics with unsurpassed precision, but will also advance the performance of our most accurate clocks.

Why:The ultra-stable frequency from a superconducting microwave oscillator probes new science because it depends in a unique way on the underlying constants of fundamental physics. Additionally, the SUMO oscillator provides a low noise signal to improve the performance for atomic clock experiments on the ISS.

“Testing Relativity with clocks on Space Station”, J.A. Lipa et al, Proceedings, 2nd Pan Pacific Basin Workshop on Microgravity Sciences, Pasadena, CA May 1-4, 2001.

John Lipa, Stanford University

Final Peer Review Date: 2004 FHA: March, 2007FP 6

Impact:Transport properties in finite systems have a broad range of relevance which transcends the helium problem. They are important, for instance, also to electrical conduction in thin wires which is highly relevant in mesoscopic systems and numerous applications.

BEST

Why BEST in space? --- Comprehensive understanding of the dynamic finite-size scalingHow: Measure the thermal conductivity of liquid helium near the superfluid transition at various pressures with cylindrical and rectangular confinement of various characteristic sizes in a combination of ground (< 10 m) and flight (~50 m) experiments. Two types of DC SQUID-based superconducting devices are employed to achieve high-resolution measurements: the High-Resolution Thermometer (HRT) for extreme temperature resolution (< 1 nano-Kelvin) and the superconducting pressure gauge for extreme pressure resolution (< 1 nano-Bar).

Capillary plate with 1-dimensional cylindrical holes (50m)

SCR panel statement:“BEST will make a landmark contribution to NASA’s Low Temperature and Condensed Matter Physics campaign.”

Why:The dynamic finite-size scaling and the effects of boundaries on transport properties of a fluid are of great scientific and industrial importance, yet have not been well studied. In order to achieve the best and comprehensive understanding, a large range of finite-size systems is required. Due to the gravity smearing effect on the ground, such large range can only be achieved in space.

Guenter Ahlers, University of California and Santa BarbaraFeng-Chuan Liu, Jet Propulsion Laboratory

Final Peer Review Date: 2004 FHA: March, 2007FP 7

Capillary plate with 2-dimensional slots (5 X 50m)

Primary Atomic Reference Clock in Space

Impact:PARCS will set new limits on our understanding of gravity as it relates to the nature of time and space while realizing the world’s most accurate clock. Techniques and capabilities developed for PARCS enable future science measurements using laser cooling and space atomic clock.

As the Laser Cooling Pathfinder PARCS will improve timekeeping while testing fundamental tenets of Einstein’s theories

How: PARCS involves frequency comparisons between high-performance atomic clocks on the ISS and on the ground. Atoms cooled to a millionth of a degree above absolute zero float through a microwave interrogation region to measure the transition used to define the base unit of time, the second. Microgravity allows long interaction times reducing effects which limit the performance of ground clocks.

Artist rendition of laser-cooled cesium clock in space.

From RDR panel report: “Second, the Panel concluded that the scientific motivation for the experiment remains excellent and the need for microgravity and the access to space is compelling. The Panel continues to fully and enthusiastically endorse the science that drives this mission…”

Why:

Atomic energy levels are among the most reproducible phenomena in Nature and are also the basis for atomic clocks. Such clocks make fertile testing grounds for physics beyond the levels of current understanding while also supporting standards needed for commerce, high speed communications, and navigation.

“PARCS: a Primary Atomic Reference Clock in Space,” Proceedings of the 1999 IEEE International Frequency Control Symposium, p. 141 (1999).

Donald Sullivan, National Institute of Science and Technology

Rubidium Atomic Clock Experiment

Impact:•RACE will explore the limits of relativity, where modern grand unified theories of the cosmos predict a breakdown of Einstein’s theory of gravitation.

•RACE and SUMO are currently scheduled to be on the ISS simultaneously. Comparisons of these two clock experiments will improve the relativity test of the anisotropy of the speed of light by over a factor of 1 million.

The Ultimate Stability and Accuracy in a space-based Atomic ClockHow:• Laser-cooled atomic clock based on high density Rubidium atomic beams. Much less noise in the clock signal than in Cesium.

•Circumvents the large shift of the tick rate due to Cs collisions that is inherent to all laser-cooled Cs clocks. High density beams lead to clock instabilities in Cs.

• Novel double clock configuration employed to reduce the cost and complexity of the electronic oscillator that excites the atoms.

Dual Clock Concept launches cold Rb atoms (in blue) opposite directions alternately to improve

clock stability and reliability

“The SCR panel identifies RACE as being of very high intrinsic value to the scientific community and that the anticipated improvements should be classified as dramatic and as timeless.”

Why:

•Advance atomic clock science to enable measurements with accuracy of 1 part in 1017.

•Significantly improve the classic clock tests of general relativity and search for violation predicted by string theory.

•Distribute the highest accuracy time and frequency from the ISS.

Kurt Gibble, Penn State University

Condensate Laboratory Aboard the Space Station

Impact:Atom lasers are expected to be the key to a new generation of “quantum technologies”, including sensors which employ atom interferometry of coherent atoms to achieve unprecedented sensitivity. Matter-wave holography has potentially significant advantages over conventional lithography techniques.

How: Laser cooling techniques are used to pre-cool a sample of rubidium atoms to temperatures a few millionths of a degree above absolute zero. The sample is loaded into a miniaturized magnetic trap. Evaporative cooling is used to cool the atoms further by ejecting the hottest atoms from the trap, to allow the remainder to equilibrate at a lower temperature. This cooling technique is continued until the BEC state forms, which is then studied by various means.

The use of BEC to demonstrate an atomic laser This research is at the forefront of advances in modern physics. It was selected from the OBPR 00 NRA

Why:The study of BEC has been one of the most exciting areas in atomic physics over the past five years. Many of the experiments that have been performed to date have been significantly affected by gravity.

CLASS will advance our understanding of the organizing principles of nature by observing free evolution of macroscopic quantum systems.

William Phillips, National Institute of Standards and Technology

Investigation Selected from 00NRA but does not have funding

Impact:Identification of the boundaries of the general relativity, and all metric gravity, is crucial to developing models that reconcile gravity with quantum mechanics. This is arguably the most outstanding problem in Fundamental Physics, today.

How: Laser cooling techniques will be used to simultaneously cool and trap both rubidium and cesium atoms. These atoms are allowed to free fall in space, while pulses of light excite Raman transitions to split and recombine the atom waves, and form the interferometers. Atom waves propagating in each arm of the interferometer experience different phase shift in their free fall, allowing the determination of the acceleration of gravity. Comparison of the acceleration experienced by the two atomic species allows testing the EEP.

This research is at the forefront of advances in modern physics. It was selected from the OBPR 00 NRA

Why:Atom, wave interferometry is an exciting new development based on laser cooling and trapping. Development of instruments based on this approach allows exacting tests of the fundamental physics, including Einstein’s Equivalence Principle (EEP). This approach towards testing the EEP is also distinguished by the feature that tests masses are comprised from atoms, which are quantum entities. Thus matter wave interferometry allows both a high sensitivity test, and one that can directly probe the coupling of gravity to mass at quantum mechanical scales.

Quantum particle-wave duality

Mark Kasevich, Yale University

QuITE will search for limits to Einstein’s relativityInvestigation Selected from 00NRA but does not have funding

Quantum Interferometer Test of Equivalence

Fundamental Physics Baselined Budget as of 01-31-2003

Prior FY’03 FY’04 FY’05 FY’06 FY’07 FY’08 Total

213.764 36.056 32.290 49.562 41.416 44.191 46.406 463.685

Future

• Had a good run

• Almost made it to ISS

• Partially recoverable…but need

• FP Community vigorous advocacy to acquire fundings and upmass– NRC Decadal Report

• Ask what NASA can do for you