RLE__%I,IJI I I ff

Volume 4, Number 1 " Fall 1990

The Research Laboratory of Electronics at the Massachusetts Institute of1ëchnology

RADIO ASTRONOMYAT RLE:All Things Celestial

Since the time ofprimitive civilizations,

earthlings have looked skyward forclues to the past and prophesies of thefuture. Familiar celestial features and

mysterious cosmic phenomena havefascinated us, even before humans de-

veloped the ability to write. As one ofthe oldest sciences, astronomy was im-

portant in the establishment of time re-

cording standards, such as clocks andcalendars, and the development of ce-lestial navigation techniques. Early ad-vances in astronomy can be traced backto the Babylonian, Egyptian, Greek, andChinese cultures.

When we examineour galaxy, wenot only see objects beaming light to usfrom more than a million light yearsaway, but we also see an expandinguniverse of celestial bodies that are rac-

ing away from us at incredible speedsto unknown destinations. Various cos-mic phenomenasuch as pulsars, qua-sars, x-ray stars, and radio galaxies raise

questions as to how we fit into the uni-verse. Astronomers strive to answerthese questions as new instrumentsandscientific methods are developedto examine the cosmos. Each new

wavelength band reveals newaspectsof the universe, and the radiosky dif-fers dramatically from what is seen byoptical telescopes.

Specific areas of astronomical

study are usually determined by a sd-

4d .IOO NI4A20

46

etotive R.0

(mi!lircec)

Professor BernardF. IJurl.'e beckonsfrom behind superimposed maps of the radiosource2016+112 (a gravitational lens) produced by the Very Large Array (VLA) and

very-long-baseline interferometry (VLB!). The radio telescope antennasofthe VLAloom in the background. A detailed description ofthese maps is on page3. (Photo byJohn F. Cook)

entist's interest and the available equip-ment. Astrophysics is a branch ofas-

tronomy that examines the physicalproperties of celestial bodies (such as

luminosity, chemical composition, size,

temperature and origin). Cosmology

investigates the overall structure of theuniverse. Radio astronomy studies ce-

(continued onpage 2)

Director's Message

Thestudy of extraterrestrial spacehas been a scientific fascination for

many centuries, aided by a succes-sion of probe technologies aimedat providing increasingly accuratemeasures of the size, motion,tem-

perature, color, and distance of ce-lestial bodies. In RLE, a broad

range of the electromagnetic spec-trum has been used to obtain andtransmit this information. Theef-fect of a very large telescope isachieved by utilizing an array ofobservation sites widely dispersedin space and utilizing interfero-metric techniques to accuratelymeasure exceedingly distant phe-nomena.The increasing size of thebaseline of these interferometersover time, from a few miles be-tween terrestrial stations, to hun-dreds of thousands of miles be-tweenspace stations, bears

testimony to the aggressive growthof measurement technologies that

permit the coordinated acquisitionof large volumes of data from syn-chronized sites. Research in radio

astronomy hasnot only built on ex-

pertise in electromagnetics, but

Projessorfonatban Allen, DirectorResearcl, Laboratory ofElectronics

also on the ability to build exceed-

ingly high-frequency receivers in

gallium arsenide, and new compu-tational image processing tech-

niques that can retrieve weak im-

ages from highly corrupted signals.In this sense, radio astronomy is a

typical example of RLE's interdisci-

plinary research programs that ef-

fectively build on the expertisearising from awide range of disci-

plines.

RADIOASTRONOMY

(continued)

lestial objects by the measurement and

analysis of their emitted electro-

magnetic radiation.

The Science of Radio AstronomyRadio astronomy is a relatively new sci-ence. In 1931, Karl GJansky at Bell Lab-oratories was investigating problems ofradio noise or static. His research un-covered radio noise emitted by the

MilkyWay, and his discovery, com-bined with advances in radar duringWorld War II, opened theway for the

development of powerful radio tele-

scopes to locate andmapthe sources ofradio waves in space.

pulled and recorded. Radiofrequencysignals from space can be easily and

precisely manipulated. Networks ofseveral radio telescopes can receive os-

cillating wave signals from distant ob-

jects, and these separate signals canbe

amplified and compared. From this

comparison, interference fringes canbe derived, and if the observations are

sufficiently complete, a radio mapofthe object can he obtained.

The first radio telescopes couldnot achieve the visual quality of opticaltelescopes because radio wave fre-

quencies are approximately I milliontimes lower than visible frequencies.The diameter of the telescope's mirroror antenna and thefrequency of the

signals are important factors for visual

quality. Theangular resolution of the

telescope also determines the amountof structure onecansee.To achieve theresults equal to that ofa 200-inch opti-

RLE currentsRl.E CUflVfltS Is a biannual publication ofthe Research Laboratory of Electronics atthe Massachusetts Institute ofTechnology.

Jonathan Allen ...............John F. Cook .................Everett Design.............

Dorothy A. Fleischer

Barbara Passero.

DonnaMaria Ticchi ....

Since no single scientific instru-ment can meet all the observational re-

quirements to study the radio sky, as-tronomers must usea variety of

equipment, such as radio telescopesandother radar equipment, to analyzeelectromagnetic waves. All telescopescollect electromagnetic waves, but indifferent forms. Optical telescopesgather electromagnetic waves from thevisible light spectrum using mirrors tocollect and focus the light. Radio tele-

scopes collect radio waves (from ap-proximately I to 30 millimeters in

wavelength) using highly directionalantennas that are usually parabolic, or

bowl-shaped. The radio wavesare fo-cused on a second antenna, and aretransmitted as electrical signals to a ra-dio receiver. The signals are then am-

HenryJ. Zimmermann

Editor-in-Chief

Photography.

Design.

Staff Writerand Editor.

Productionand Circulation.

ManagingEditor.

Advice and

Perspective

The staff of currenis would like to thankProfessor Bernard F. Burke for his techni-cal guidance during the preparation ofthis issue.

Inquiries maybe addressed to RLEcurrents, 36-412, Research Laboratory ofElectronics, Massachusetts Institute ofTechnology, 77 Massachusetts Avenue,

Cambridge, MA 02139.

(ISSN 1040.2012)

CND RLE© 1990. Massachusetts Institute of Technology.

All rights reserved worldwide.

cal telescope, a radio telescope wouldneed an antenna many miles in diame-ter. This is the idea behind very-long-baseline interferometry (VLBI), whereseveral radio telescopes are combinedto produce angular resolutions betterthan one second of arc. The Very Large

Array (VIA) in the New Mexico desertconsists of 27 antennas, each 88 feet indiameter. Thearray is spread across the

plains of St. Augustine, with a maxi-mum extent of over 20 miles. It can

produce images of the radio sky that ri-val those of an optical telescope.

In previous times, telescopes wereused to collect faint light and allow theobserver to see with greater detail and

sensitivity. Today, instruments, such asthe spectroscope, canbreak light intovarious colors of the spectrum. It ex-

ploits the fact that when chemical ele-ments are heated to high temperatures,they emit light which can be separatedinto a spectrum by passing it through a

prism. No two chemical elements havethe same spectrum. Molecules also ex-hibit spectra, and the different proper-tics seen in the spectra ofstars, planets,and galaxies can be studied to investi-

gate their chemical composition, tem-

perature, atmospheric pressure, speed,and direction. For example, the relative

brightness of thespectrum at different

wavelengths indicates temperature,and the patterns made by dark lines in-dicate chemical composition. Scientistscan often determine an object's tem-

perature, pressure, andthe density ofits center from the observed spectra.Spectra from different planets can alsoindicate the chemical composition oftheir atmosphere. In former times,

spectra were studied at optical wave-

lengths, but the advent of radio astron-

omyhas broadened the field, and radio

spectrometers can now measure the

spectral properties of the interstellar

gas. The same techniques are also ap-plied to studies of the Earth's atmo-

sphere, since oxygen, water, and ozoneall have characteristic spectral features.

Radio Astronomy at RLEProfessor Bernard F. Burke carries outan extensive observational programcombined with an experimental pro-gram in VLBI that focuses on

gravitationally lensedquasars. His

group actively searches for newgravita-tional lenses using the MIT-Green Bankradio source catalog for a list of possi-ble candidates. In this study, interfero-

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z-Jo 44-W

,40 20 0 -20 -40

- D 20 0 -20

-40RELATIVE R.A. (milliarcsec)

20 16 55.5 55.4 553 55.2

RIGHT ASCENSION

These VLAand VLBI maps illustrate the radio source 2016+112,a gravitational lensstudiedby I'rofessorBernardF Burke. Thisphenomenon occurs when thegravitation-alfield ofa massivegalaxy (orgroup ofgalaxies)focuses 11gb/froma distant quasarflea,-oralong itslineofsight, thusgiving multiple images ofthequasar. Thisparticulargravitationallens wasfirst ident(fied by the RLE'SRadioAstronomy Group. Recent VIBIstudies show that each quasar, at radio wavelengths, hasasimilarstructure on amilliarcsecond scale. The inset VLBI maps are magnifiedto scale 50 times.

metric methods are used to measurethe radio distribution and polarizationofmultiple images formed by the inter-action of intervening matter with radioemissionsfrom distant quasars. Two

examples of Einstein rings, a particularform of gravitational lens, have beenfound, wherea distant radio source isso accurately aligned with a foregroundgalaxy that it formsa ring-like image.One recent discovery was configuredin such away that highly accuratemeasurements were gathered of the

mass-to-light ratio from the central partof the foreground galaxy, thus settinglimits on the amount of dark matterwithin that galaxy. The search for gravi-tational lenses has prompted a newsur-

vey that Professor Burke anticipateswill find more of these phenomena.Professor Burke is also involved in sev-

3

eral international VLBI projects that useradio telescopes on orbiting satellitesto extend interferometric baselines to

separations greater than the earth's di-ameter.

Professor David H. Staelin and hisstudents are involved in passive micro-wave studies of the planets (includingEarth), studies of nonthermal radioemission of pulsars and planets, andthe development of long baseline opti-cal interferometry to measure stellarsize and position. Early observations ofthe atmospheric spectra ofVenus,Jupi-ter, and Earth led to the ongoing devel-

opment of current and future Earth-or-

biting weather satellites, which beganwith the Nimbus-5 and Nimbus-6 mi-crowave spectrometer experiments.

(continued onpage 5)

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3164145.2 60HOURS UT

This astp-ometric inteiferometer delay line offset (in microns) observed atMount Wilson showsfluctuations due to atmospheric temperature in-homogeneitiesas afunction oftime. Black crossesshow one-colorperfor-mancc andredcrosses show improvedperformanceofthe two-colorcorrec-tion scheme. The residual drift arisesfrom random mirror motion and

humidity variations. The two-color tnethodfor interferometric astronomycan reduce the error in stellar position measurements due to atmosphericturbulence.

Professor David 11. Staclin conductspart ofh/c researchat the Mount Wilson Astrometric Intetferometerfacilityin California. This facility, jointly developed by theNa-valResearch Laboratory, the Smithsonian AstrophysicalObservatory, andRI..'?, has improved theaccuracy ofex-

isting astrometric observatories, and has demonstrated

technology that will enablefurther improvements. Stel-lar diameters and the relative posit/on ofhundreds ofstars have been measuredat Mount Wilson. Fop- exam-

ple, the orbttalparameters ofAlpha Andromeda, a closebinary star, has been measured with nearly 100 micro-

arcsecond root-mean-square accuracy. (Photo byJohnP Cook)

Principal Research Scientist Dr. Philip W. Rosenkranz develops algorithms to processmeasurements of the Earth taken by the Advanced Microwave Sounding Unit (AMStijwhich will be one ofthe instruments used in the nextgeneration ofweather satellitesfor the National Oceanic andAtmospheric Administration (NOAA). Dr. Rosenkranz's

computer display shows measurements taken over the eastern Pacific Ocean hy theSpecialSensor Microwave Imager (SSMIIJ which cut-rentlj' observessome ofthe same

frequencies that the AMSU will observe in itsfuture program. The SSM/1 is also used totestDr. Rosenkranz's algorithmsfor infrrence ofvapor and liquid water in theatmo-sphereand wind speed near the Earth's suiface. Thefigureshows the sensitivity of tem -perature-sounding channelsas a,function ofpressure level in the atmosphere.(Photo byJohn F. Cook)

4

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NADIR VIEW

05 geuss0. 45"

0" 62 63 04 05 0¬ TWEIGHTING FUNCTIO$LA VAIn p

Professor Jacqueline N. Hewitt's research involves radio astrono-

my, signaiprocessing, and imageprocessing techniquesto acquire

high-resolution images ofgravitational lens systems, and the use

ofthese lensesto addressproblerns in astrophysics. Professor/knit!uses the datagathered to characterize the gravitationalpotentialwhich produces the lenses, and its effect on light rap andradenwave propagation. A calculated image ofa gravitational 1ei

(red) issuperimposedon a contourplot ofthegravitationalpote 1-hal thatproduces this lens (black), These calculations are used to

findthe best modelto describe the gravitationalpotential, and to

predict observableproperties ofthe lensed images. This ;nodel,forexample, describes well theproperties ofa gravitational lens ob-

served with the Very Large Array (VLA) radio telescope. The imagehere is displayedata muchhigher resolution than can be observedwith the VIA but at a resolution accessible with very-long-baseline

interferonetry (VLBI. VLJ3I measurements should show the arcsthatare characteristic ofgravitational lensing.

Professor Staelin wasthe principal in-

vestigator for these experiments. As co-discoverer of the Crab Nebula pulsar,which helped to establish the existenceofneutron stars and such forms of mat-ter, he continues to study similarnonthermal radio emissions from the

planets and associated emissionmechanisms. Professor Staelin is co-in-

vestigator for the Voyager Planetary Ra-dioAstronomy experiments, and usesthe data gathered from Jupiter, Saturn,Uranus, and Neptune. He has also par-ticipated in developing the Mark I, II,and Ill astrometric interferometers atMount Wilson Observatory in Califor-nia. These interferometers haveestab-lishednew levels of precision for stel-lar position and size measurements,and will lead to a new generation ofmore accurate systems.

The radio image ofan Einstein ring gravitational lensprovidesafiery backdropfor I'rofessor Jacqueline N. hewitt. An Einsi'ein

ring gravitational lens isaparticularly symmetric case ofgravi-tattonal leasing where the source is imaged into a ring. Thephe-nomenon received its name because Einstein suggested deflec-tion ofstarlight by thesun, anda ring that would appear fstarswereperfectly aligned. (Photo byJohn F Cook)

ProfessorJacquelinc N. Hewitt'sresearch interests include gravitationallenses and nearby stars. ProfessorHewitt has identified several gravita-tional lens systems, and her efforts to

exploit these systems employs the VIAandVLBI imaging techniques, as well asmodels of the gravitational field. Scien-tists anticipate that studies of gravita-tional lens properties will provide newestimates of theHubble constant (thespeed at which the expansion of the

galaxy increases with distance), andhow much dark matter is distributed invarious galaxies. Data analysis is beingconducted to determine whether Ein-stein rings can be used to measure theI lubble constant. Professor l-lewitt's in-

vestigations have shown that the low-level, quiescent emission oflow-tem-peraturemain-sequence stars can be

detected with sensitive VLBI arrays.Therefore, VLBI studies may providenew measurements of perturbationsdue to possible nearby planets andof

parallax distance. Data gathered withthe VLBI array will he used to create mi-croarcsecond images of stars and to in-

vestigate radio emission stability.Principal Research Scientist Philip

Rosenkranz conducts research into at-

mospheric remote sensing of the Earth

using microwave radiometers to im-

prove the measurement ofatmosphericparameters such as temperature. Dr.Rosenkranz has proposed the use ofanew instrument to sound, or measure,the mesosphere and upper strato-sphere that will contribute to studies ofthe middle atmosphere. He also contin-

(continued on page IQ)

U L T Y P R 0 F I LE

FACULTYPROFILE:Bernard F BurkeBoston native andWilliam A. M. Bur-den Professor ofAstrophysics BernardF. Burkecompletedhis SB in 1950 andPhDin 1953 at MIT. In 1953, hejoinedthe Department of Terrestrial Magne-tism at the Carnegie Institution in

Washington andbecame asection

managerin 1957..Upon his return toMITin 1965 as Professor ofPhysics,Professor Burkeintroduced interfero-metric techniques at the Haystack Ra-dio Observatory in Westford, Massa-chusetts. As leader ofRLE's researchgroup in this area, heshared the 1971

RumfordPrize awardedby the Acade-

my ofArts andSciences.Together with theNational Radio

Astronomy Observatoryandthe Cana-dian National Research Council, his re-search group developed techniquesforvery-long-baseline interferometry(VLBI). This method uses atomicfre-quency standards to synchronize radio

telescopes at remote locations aroundthe worldandhas improved angularresolutionforradio telescopes by1,000-fold. Professor Burkec groupwasalsofirst to conduct inter- andtranscontinental VLBI. Recently, he hasserved as the US. principal investigatorto develop orbiting VLBI stations andhasalso participated in European andSoviet VLBI mission studies.

He has served as Visiting Professorat the University ofLeiden (1971-72),Sherman Fairchild Scholar at the Cali-

fornia Institute ofTechnology (1984-85), andheldaSmithsonian RegentsFellowship in 1985. In 1963, he re-ceived the Warner Prize of the Ameri-canAstronomical Society and, in1988, was corecipient ofaNASA GroupAchievementAward. He servedas Presi-dent of the American Astronomical So-ciety (1986-88), is Fellow ofthe Ameri-canAcademyofArts andSciences, andwaselected to the NationalAcademyofSciences in 1970. He chairs and serveson several advisory boardsfor NASAand the National Science Foundation,andparticipates on the editorialboards ofmanyprofessionaljournaLc.

ow~_' 72, -As currentsgoes topress, Professor Ber-nard F Burke has been nominated byPresident George Bush to asix-year termon the National Science Board, thegov-erning body ofthe National ScienceFoundation. His appointment awaitsSenate confirmation. (Photo byJohn FCook)

'How didyour interests in radio as-

tronomydevelop?

I was agraduate student in Rl.E, I be-lieve it was 1951, andAl Hill was direc-tor of the lab. One of ourold RadLabfriends wasTaffy Bowen, who hadgoneon to direct the Radio Physics Divisionof the Commonwealth Scientific Indus-trial Research Organization in Austra-lia. Al met Taffy at some affair in Wash-

ington, and Taffy told him about the

great things that were happening in ra-dio astronomy. So, Al asked Taffy tocome to MITand give a series of lec-tures. Therewere three lectures: onewas on the sun, anotheron the moon,and anotheron everything else in theuniverse. Al's hope was that oneof the

faculty members would catch tire after

hearing the lectures, and start radio as-

tronomy at MIT. That didn't happen,but there was onegraduate student atthose lectures who realized there arewide horizons when you're just startingout in life. Ayear later, as the endofmydegree came in sight, I began to in-

quire about where I might go after

graduation. MITwasstarting its firstmoves to establish Lincoln Lab, andoneof their consultants was Henry Bookerfrom Cornell. Through 1-lenry, Ilearned about a new program at the De-

partment of Terrestrial Magnetism at

the Carnegie Institution ofWashington,and I started my first postdoc there in

September 1953.

.Asastudent in RL4you worked onmicrowave spectroscopy with Profes-sor Woody"Slrandberg Washeyourmentor?

I was Woody Strandberg's graduate stu-dent, and although our work in micro-wave spectroscopy was completely lab-

oratory oriented, it prepared me withall the tools I needed to go into radio

astronomy.Woody was my mentorwhen I was a graduate student, butwhen I went into radio astronomy, Ihadto go to another institution. MerleTuve was certainly my mentor at Carne-

gie.

*AtCarnegie you codiscovered thatJupiterwasastrong radio source withKenneth Franklin in 1955. Howsig-nificant was thisfinding?

It was very exciting when we discov-ered radio noise from Jupiter. It was

completely unexpected because the in-tensities of the radio bursts were somuch greater than any theoretical pre-diction had made them. We thoughtperhaps it was lightning. But, it turnedout there wasn't any lightning onjupi-ter because the noise was millions oftimes stronger. Then,we discoveredthat the noise was circularly polarized,which meant that somehow there hadto be a magnetic field involved, We andseveral other groups were able to showthere was a periodicity in the noise.But, the periodicity was not related tothe rotation of the planet as we saw it,because the clouds have a west-to-eastcirculation. Instead, there wasa slightlyslower rotation whichwas noticed byother people. So, three groups realized

simultaneously that we were seeing thetrue rotation ofJupiter.Then, friends atthe National Radio Astronomy Observa-

tory (NRAO) detected a different kindof radio noise at a higher frequencyfromJupiter. TheVanAllen belts had

just been discovered around the Earth,and quickly we realized that Jupiteralso had Van Allen belts. I like to pointthis out as an example of unexpectedconsequences. The radio astronomerswere able to show that theVan Allenbelts OfJupiter were so intense that any

FACULTY PROFILE

spacecraft traveling there would haveto he radiation hardened.

" What enticedyou to return toMIT in1965?

When Woody Strandherg was my thesis

supervisor, he arranged for me to do

part ofmy work at Brookhaven. That in-volved doingsome of my work at Co-lumbia, where CharlesTownes had aresearch group. I spent several weeks

there andgot to know Charlie.When hebecame Provost at MIT, he delegated AlBarrett to talk to me and inquire if I

might be interested in a position. I did

enjoy teaching, and although I had a

purely research position at Carnegie, Ialso taught a radio astronomy course atthe University of Maryland. Anotherfactor was that Harvard and MITwere

collaborating on a project to build a

very large radio antenna in New Eng-land.So coming back to MITwasboth a

joining of my research interests and mydesire to take up teaching.

*How did RLE's work in radio aslmn-omy evolve?

Letme first say what didn't happen. MITwas marvelously positioned to go intoradio astronomy because we had all

this gear left from the Rad Lab. Therewas much to do after the war, so the

laboratory physicists went back to labo-

ratory physics, much of which hadbeen stimulated by the RadLab. Radio

astronomy mainly started in the Neth-erlands, in Britain atJodrell Bank andthe University ofCambridge, and inAustralia. They weren't rich, but theyhad lots ofgear, and radio astronomy is

somethingyou can start with eagerpeople anda minimum of equipment.So, that's why it started elsewhere. Inthe United States, only the Naval Re-search Laboratory had a radio astron-

omygroup. Cornell did too, but it pe-tered out.

The first act of radio astronomy atMIToccurred in the early '60s, when

Jerry Wiesner was Director of RLE andPresident Kennedy's Science Advisor, IthinkJerry had a secret desire for MITto build up a program in radio astron-

omy. One ofJerry's graduate students,

SandyWeinreb, developed a correla-tion spectrometer for radio astronomyas his thesis topic. lie couldn't do it at

MIT because there were no facilities,

except to build and test the electronics.Theactual observations were done atthe National Radio Astronomy Observa-

tory in Green Bank, West Virginia.Sandyused to joke that he shared histhesis supervisor with President Ken-

nedy!Charlie Townes came to MIT, and

he was interested in radio astronomy.Al Barrett had just joined the faculty,and Lincoln Labwas building the Hay-stack Observatory. Al collaborated withthe Lincoln people, and since Haystackwasn't built yet, they used the Millstoneantenna. In 1963, they were the first todiscover a new spectral line, the hy-droxyl (01-I) line. This was a collabora-tion between Sandy Weinreb, M. L. "Lit"Meeks, and Al Barrett. I believe one of

The first act of radio astron-omy at MIToccurred in theearly '60s, when JerryWiesner was Director ofRLEand President Kennedy's Sci-ence Advisor.

the first modern achievements at MITwas to develop the autocorrelationmethod for radio astronomy, and theOH line was the first major astronomi-cal discovery made with that technique.

When I returned to MITin 1965, 1was interested in using Lincoln Lab.But, I will be frank andsay that LincolnLab was not entirely enthusiastic aboutit. I think they were afraid the radioastronomers would use 1-Iavstack toomuch. Or maybe, they wanted the radioastronomers to bring more moneywiththem. However, Paul Sebring, theDi-rector of Haystack, wasvery supportive.He enjoyed the radio astronomers be-cause he realized they were doingsome of the most exciting work. I hadbeen here just a few months, and I was

casting around for something to do.The01-1 lines were shown to have verypeculiar properties in certain regions,and the intensity in emissions was far

stronger than predicted. So, I proposedthat the Millstone and Haystack anten-

nas he used together as an inter-ferometer. This wasn't VLBI yet, it was

just a regular interferometer that wouldshow the OH sources were very smallin size. It was a great collaboration in-

volving Al Barrett, his two graduate stu-dents Al Rogers andJim Moran, andmy-self. Our first experiments weresuccessful, and showed that the maserswere so small in size that their bright-ness had to be much higher than anytheoretical prediction.

We decided that a longer baselinewas needed, andsince we knew peopleat Harvard from theCamroc antenna

project (this was a plan for a 100-meteror larger antenna), we put together acollaboration using their Agassix Sta-tion telescope and Millstone. We suc-

cessfully brought the telescopes to-

gether with a radio link because theywere too far apart, and this gave us abaseline 20 times longer than the Mill-stone to Haystack baseline. It alsoshowed that things were of the order ofan arcsecond in size. That was a veryexciting discovery.

During the radio link experiment,another experiment done by Al RogersandJim Moran involved deliberatelyopening the radio link so the twoantennas operated separately. Wecould still sec interference fringes,which meant the oscillators were sta-ble. The NRAO was developing a simi-lar set ofexperiments using separateantennas; the Cornell and Green Bankantennas. Their experiments weren't

working, andthey weren't keeping it asecret. (This is a nice illustration of whyyou should tell people what you're do-

ing.) I remember walking up a stairwaysomewhereon campus with Al Barrett,andI said to him that we could use sep-arate local oscillators and separate re-corders to do a very-long-baseline ex-

periment. And he said he had been

thinking of something like that too!In February 1967, I sent letters

proposing the experiment to Paul Se-

bring at Haystack and Dave l-Iecschen,the Director at Green Bank. We did ourfirst experiment in Maywith some ur-

gency, since it was a bit of a horse race.The first successful experiment wasclaimed by the Canadians. The NavalResearch Laboratory and NRAO alsodida successful experiment a fewweeks before us. But, they were work-

FACULTY PROFIL

ing at a much lower frequency, and wewere pushingup to higher frequencies.The measure ofoursuccess came when

everyone switched to our frequency,the OH line frequency. The importantthing is that the Canadians, the NRAO,and ourselves were using differentmethods at the same time, and we en-

joyed the collaboration.In the late '60s, much of our effort

went toward developing VLBI at higher

I believe one of the first mod-ern achievements at MITwasto develop the autocorrela-tion method for radio astron-omy, and the OH line was thefirst major astronomical dis-covery made with that tech-nique.

frequencies, and George Papadopouloswasagraduate student whotook up the

project. We moved up to the waterline

frequency at 22 gigahertz and success-

fully performed an experiment a few

years later. At the same time, weworked to increase the baseline to gethigher angular resolutions. We also didthe first transcontinental and first inter-continental VLBI. I remember that be-cause one of my graduate students wasin Sweden, I was in northern Californiaat Hat Creek, and George was at GreenBank.We had our personnel strung outacross theglobe for that experiment!TheVLBI research was geared to get-ting longer baselines, more astrophys-ics (that is, the study of maser proper-ties), and shorter wavelengths.

At about thesame time, my gradu-ate student Ted Reifenstein was atGreen Bank working on a special spec-trometer used to study hydrogenrecombination lines (sometimes calledKardarshev lines). Another graduatestudent, TomWilson,was in Australiato map the hydrogen recombinationlines in the southern hemisphere forNRAO. Also at the same time, Marty Ew-

ing helped us prepare an experimentto measure black body radiation fromthe top ofWhite Mountain. It was fun

becausewe had to go up to 12,000 feetand work under adverse conditions.

Marty Ewingand Dave Staelin took thebrunt of that adventure. Of course,Cosmo Papa andJack Barrett built the

equipment, so it was agroup effort. Wemade a 9-millimeter measurement thatshowed the cosmic microwave back-

ground had the same effective

temperature at 9 millimeters and atlower frequencies, So, many different

things were happening at that timewithin ourgroup.

Various types of interferometrycontinued into the '70s, and the NRAOstarted a newproject called the VeryLarge Array (VIA). By this time, it was

quite clear the Camroc antennawasgo-ing nowhere. TheVietnam conflict had"taken care" of science budgets. So, theone show in town was the VI-A. Since Iknew a lot about interferornetry, it wasa natural activity for me. I served ontheir advisory committee, and I becamea trustee of the Associated Universities,which is responsible for the NRAO andfor Brookhaven. I hadgreat interest inthe VIA, and I wanted to ensure its suc-cess. Graduate student Perry Green-field and I became experts with theVIAbefore it was finished. Interferometersare like that; even when there are onlya few antennas, you can still makeobservations.

In 1979, radio astronomers at Jo-drell Bank were working with RayWei-man at the University of Arizona. Theydiscovered a particular radio sourcethat was an example of gravitationallensing.TheVIA's interferometric

properties made it a natural instrumentto use, and we produced the first radio

map of that source. That interested usin the properties of gravitationallenses. Although we continued to doVLBI and to study the 011 and water-lines, the lensing work gradually be-came a larger part of our activities.

In the early '80s, not many large-scale surveys of radio sources wereavailable at the high frequencies weneeded to look for new gravitationallenses. It was an ideal graduate student

project, so we sent several of them toGreen Bank to use the old 300-foot

telescope. We started a survey that be-came known as the MIT-Green Bank

Survey, using Green Bank equipmentand many MITgraduate students.

Chuck Bennett and Charles Lawrencewere the first vanguard of MITstudentsto use that telescope to survey the sky.We used the survey as a guiding sourcelist to do a larger study with the VLA,andwe mapped 4,000 sources. Many ofour graduate students have worked onthis survey-Jackie Hewitt (now on our

faculty), Antonio Garcia-Barreto, Glen

Langston; and more recently, Sam Con-ncr, Joe Lchr, and Mike Heflin.

We started a new search for gravi-tational lenses using that body ofwork.Charles Lawrence found the second ex-

ample of a radio gravitational lenseswhen he noticed a peculiar source. As

things developed, Jackie Hewitt discov-ered the first Einstein ring, and Glen

Langston found the second Einstein

ring a year later. This came out of adec-ade of work that started with graduatestudents learning the business of radio

astronomy with the 300-foot transit

telescope at Green Bank. In November1988, the oldantenna collapsed, andthat ended this phaseof ourwork. But,

they will he building a bigger and bet-ter antenna; the kind of antenna thatshould have been built for the Camroc

project 25 years ago. Green Bank is oneof the world's best locations for this

particular antenna. So, it's going to bein the right place at the right time. Thenewest array will be the very-long-baseline array, or VLBA, which is in the

process of being built. Craig Walker, anMITgraduate student whowasactive inVLBI in the '70s, is oneof thekey peo-

My interaction with Jin Kongin RLE's Center for Electro-magnetic Theory and Appli-cations is an example ofhowcross-disciplinary work canhave good effects.

pie involved with the technical aspectsof that project. TheVLBA is supposed tobe in action by 1993, andwe're lookingforward to using it very much.

We also became interested in

expanding VLBI in space. We'veworked with NASA to put radio anten-

FACULTY PROFILE

nas on satellites in order to get longerbaselines. Unfortunately, NASA doesn'thave funds to do this. But, the Sovietsand the Japanese have started projects,and I've been involved with both ofthem.TheJapanese have started the

VLBI Satellite Observing Platform, orVSOP.(One of the Japanese scientistsinfluential in starting the project had asense of humor becauseVSOP alsostands for very superior old pale bran-

dy.) The Soviets also have a project,called RADIOASTRON. Originally, Eu-

rope and the IJ.S. planned to collabo-rate on building a satellite called Qua-sat, andaworkshop washeld in 1984 inAustria. If you look at theRADIOAS-TRON project, it looks very much likethe Quasat project. But I don't feel bad-

ly, since we didn't have the money, weshouldn't he dogs in a manger. The So-viets andJapanese will do it, and theU.S. will use its ground facilities to helpmake these satellites a success.

" There seems to be extensive interna-tional cooperation within radio

astronomy, in contrast to thecompeti-tivenessfound in other technologiesWhatdoyouattribute this to?

It has to do with the waythe field has

developed. Radio astronomy is asmallfield, and the radio astronomers of theworldgot to know each other when wewere all young. Having a personal rela-

tionship makesa great deal ofdiffer-ence. There's competition as well be-cause people like to be first. Thecollaboration with the Soviets, for ex-

ample, was helped by an effort that oc-curred in 1959. Stalin had been deadfor several years, and the Soviet andAmerican Academies ofSciences want-ed to reestablish scientific contacts be-tween the two countries. One of thefields that they decided would be goodto encourage was radio astronomy. A

delegation ofyoungSoviet astrono-mers came to theU.S., and a sympo-sium was held.We got to know eachother on a personal basis, and I thinkthat established contacts that have en-duredover the years. There wasa theo-retical Soviet astrophysicist namedJo-sefSlovsky, who was instrumental in

promoting these contacts. He was re-

garded for many years as being politi-cally unreliable by the Soviets. So, he

Faculty, staff, andstudents ofRIB'sRadioAstronomy Groupmeet to discuss researchresults (clockwisefrom left): ProfessorJacquelineN Hewitt, SponsoredResearch Tech-nicalStaffmembrJohnW. '7ack' Barrett, graduatestudent SamuelR. Conner, l'rofes-sor Bernard F. Burke, andgraduate students AndreB. Fletcher, Grace Chen, andJo-seph Lehár, (Photo byJohn F. Cook)

couldn't leave the country himself, buthe encouraged young people to get toknow theWesterners whenever theyvisited. Also, Vitaly Ginzhurg wasan-other Soviet scientist whowas instru-mental in promoting international rela-

tionships. On theJapanese side, thereare the Japanese scientists "Mori" Mori-moto and Menoru Oda. Oda wouldhave been a professor at MIT, exceptthat he wanted to return toJapan, andhe is very supportive of developinggood relations between the U.S. and

Japan.

"What isyour role on the various in-ternational VLBIgroups?

I play a collaborator's role whereI at-tend joint meetings of the U.S. andJa-pan. I'm also chairman ofa NASA groupthat is in charge of the U.S. aspects ofcollaboration with both the Soviets andtheJapanese. The Europeans are also

cranking up an effort called the Inter-national VLBI Satellite (IVS), and I'm amember of that group as well.

*Doyoucollaborate with otherRLEresearch groups?

My interaction withJin Kong in RLE'sCenter for Electromagnetic Theory and

Applications is an example of how

cross-disciplinary work can have goodeffects. Recently, we were contacted bythe Department of Transportation, spe-cifically the section concerned with theFederal Aviation Administration. TheFAAwanted to develop a better landingsystem for aircraft in bad weather,called the microwave landing system. A

problem with the present system is thatit's running out of frequency spectrumspace. So, they needed someone tolook at the problem, but someonewhodidn't have a conflict of interest, yetsomeonewho knew the business. Sincethere is a strong disagreement aboutthis issue between the pilots, airlines,

airport operators, and industry, it was

necessary to bring in people from theoutside. Jin and I represent two differ-ent aspects, so we were brought in asconsultants. Previously, I had beenchairman of a National Academyof Sci-ence committee called theCommittee

FACULTY PROFILE

on Radio Frequencies, whoselob it wasto protect certain clear bands of the ra-diospectrum so that radio astronomycould work properly.While serving onthat committee, I got to know the fre-

quency management game pretty well.

Jin has put together the project, and Iact as a consultant. It's an interestingexample of cross-disciplinary fertiliza-tion.Jin and I have different approaches,so it's avery complementary thing.

" What is the biggest issuefacingyourfield ofresearch today?

First, astronomy is expensive, and Ithink that getting the funding fornewfacilities is a big factor. Without new fa-cilities, you're in danger of stagnation.But, new facilities always cost morethan the old facilities. Second, groupslike ours that encourage people to do

practical things find it hard to get thefinancial support that allows the labora-

tory work to proceed. Pressure is fo-cused on immediate achievement, andthe wayto get achievement quickly is to

go to a national observatory or to Hay-stack (which is practically a national ob-

servatory) and make observationsthere; then you become a user. There'sa severe danger that the practical peo-plewho make things happen are not

going to get trained as they once were,and I think the whole country will feelthis loss. That's a deeper feeling, thefirst one's more immediate. But, youhave to worryabout infrastructure, andno one in a position of powerseems to

worryabout infrastructure. You canlive off your capital, but after twentyyears, all the people whoknew how

things work are gone, then you havetrouble. So, there's trouble down theroad, not trouble here and now. Long-range planning is a problem.

" What is the most rewarding aspect of

your work?

Personally, I've had marvelous stu-dents, and my relationships with themhave been most enjoyable. I nevercould have been successful withoutthem. They multiply your power.Scien-

tifically, we've been fortunate with new

things happening all the time, so it justgoes on from oneenjoyable aspect to

another-keeping it fresh and new.

.Doyou seeyour workprovidinga

benefit to society?

Astronomy gives an indirect and long-term benefit. One example is that the

discovery of the radiation belts ofJupi-ter hadan essential impact on the spaceprogram. Much of the rapid develop-ment of space technology was possiblebecause space research people wereable to take radio astronomy telescopesand usethem directly. Later, they modi-fied them explicitly for their purposes.

- . . keeping your mind openis so important because youmay have to change direc-tion. I think radio astronomyis a field where your prepara-tion gives you a broad base,so changing direction is easy.

But, the first ones that were built wereradio telescopes. You can't put a dollarvalue on that. It meant that in an essen-tial field, the U.S. was accelerated byseveral years because we were therefirst. I think we also encourage the de-

velopment of electronics, we're press-ingon the frontiers ofwhat can bedone in electronics.

*Do you have adviceforpeople con-

templating a career in radio as-

tronomy?

Keep your eyes open, keep your mind

open, and love your science. After youget your bachelor's degree, first there'sfour or five years of graduate workthat's immediately in front of you, andthen a career that will last for another

thirty or forty years. Who'sgoing to ex-

trapolate over that? That's why keepingyour mind open is so important be-cause you may have to change direc-tion. I think radio astronomy is a fieldwhere your preparation gives you abroad base, so changing direction is

easy. You're prepared to do lots of

things.

RADIO ASTRONOMY

(continuedfrompage5)

Sponsored Research Technical StaffmemberJohn W. 'Jack" Barrett nod/es

a high-altitude wingpod that willper-mil mesospheric temperature observa-

lion and improved microwave trans-

mittance ofstratosphere and meso-

sphere observations. His experiment

supportsfuture scientificandoper-ationalgeosynchronous satellites, and

will help to improve the interpretationof microwave datafrom existing weath-

er satellites. (Photo byJohn ! Cook)

ues to develop autocorrelation tech-

niques to measure mesospheric ther-mal emission from atmosphericoxygen that may have future applica-tions for weather satellites.

Research StaffJohn W. "Jack" Bar-

rett provides engineering and technical

support to RLE's Radio Astronomy

Group. He is responsible for the de-

sign, construction, and evaluation of

microwave radiometers and other

equipment used in the group's radio

astronomy applications. In 1988, hewas corecipient (with Professor Burke)

of the NASA Group Achievement Awardfor the exceptional planning and ex-

ecution of the Tracking and Data RelaySatellite Very-Long-Baseline Interfer-ometer. These demonstrations wereconducted in 1986 and 1987 and pro-duced the world's first astronomical

space-ground VLBI observations.

by Dorothy A. Fleischer fie

I%1'L1

g,1,11 %,Lit I IJI 4tILI

While on sabbatical at Lalubriclge n1-

versity in England earlier this year, Dr

Jonathan Allen (ScD 68), Director ofRLEand Professor of Electrical Engi-neering and Computer Science (right),had the opportunity to meet Dr. Ste-

phen W. Hawking. Dr. Hawking is Luca-sian Professor ofApplied MathematicsandTheoretical Physics at CambridgeUniversity and author ofA BriefHistoi'ofTime: From the Big Bang to Black

Dr Bruno (oJ)i, Proft'ssor ot Physicsand member of RLE's Plasma Physics

Holes. Dr. Hawking suffers from a seri-ous, physically debilitating disease, and

although he cannot talk, he is able tolecture and communicate with the aidof a speech synthesizer that uses algo-rithms developed by Professor Allen inhis MITalk text-to-speech research.Here, they discuss possible improve-ments to the current synthesizer afterone of Dr. Hawking's lectures. (Photoby Ann C. Allen)

group, delivered the keynote addressto theTwo Worlds Science Conferenceheld in Charleston, South Carolina, on

May 26, 1990. Professor Coppi, widelyrecognized for his contributions to thefield of plasma physics, was the first sci-entist to deliver a keynote speech to theTwo Worlds Conference. The confer-ence was sponsored by the Sigma-TauFoundation, and held as part of the

Spoleto Festival USA, affiliated with thethree-week Italian Spoleto Festival held

annually in the tJrnbria region of Italy.The Sigma-Tau Foundation sponsorsthe Two Worlds Conference to pro-mote the interplay of scientific and hu-manistic cultures. (Photo byJohn F.Cook)

A research group led byDrJaeS Lim(SB '74, SM '75, ScD '78), Professor ofElectrical Engineering and ComputerScience, has developed avoice codingtechnique selected by the InternationalMaritime Satellite Organization (IN-MARSAT)and Australia's National Satel-lite System (AIJSSAT) as the standardfor both the INMARSAT-M mobile satel-lite communications system and AUS-SAT's MOBILESAT service. INMARSAT

operates global satellite communica-tions systems for maritime, aeronauti-cal, and land mobile applications. The

algorithm developed by ProfessorLim's group will be the standard forboth the INMARSAT-M telephone sys-tem and for AUSSAT's MOBILESATser-vice, the world's first dedicated landmobile satellite voice anddata to pro-vide full mobile coverage of Australiaand its coastal waters. (Photo byJohnF. Cook)

Dr Alan V. Oppenhein (SB/SM '61,ScD '64) was appointed Distinguished

Professor of Electrical Engineering in

September. Since joining the MIT facul-

ty in 1964, Professor Oppenheim's re-search interests have been in the areasof speech, image, and geophysical sig-nal processing. He has received manyawards for outstanding research and

teaching, including the 1988 IEEE Edu-cation Medal, the 1984 IEEE CentennialAward, and the Society and TechnicalAchievement Awards of the IEEE Soci-

ety on Acoustics, Speech and SignalProcessing. Professor Oppenheim isthe author and editor of several widelyused textbooks in signal processingand is a member of the National Acade-

my of Engineering and aFellow of theIEEE. (Photo byJohn F. Cook)

Dr. William F Sc/jreibcr, ProfessorEmeritus of Electrical Engineering andformer Director of the Advanced Tele-vision Research Program, retired fromthe Institute in June 1990, after 31 yearson the faculty. During that time, Profes-sor Schreiber pioneered developmentsin the field of image processing andtransmission coding (see cunvnts,vol. 3, no. 2). Most recently, he washonored with the David Sarnoff GoldMedal Award from the Society ofMo-tion Picture and Television Engineers.The award cites his development ofnew techniques and equipment fortelevision engineering. ProfessorSchreiber plans to continue his work inhigh-definition television and graphicarts color processing systems, and as anexpert witness in patent cases. (PhotobyJohn F Cook)

Dr. DavidH. Staelln (BS '60, MS '61,ScD '65), Cecil H. Green Professor ofElectrical Engineering, was appointedAssistant Director of Lincoln Laborato-

ry, effectivejuly 1, 1990. Professor Stae-un has been affiliated with RLE's Radio

Astronomy group since 1959 and

joined the MITfaculty in the Depart-ment of Electrical Engineering and

Computer Science in 1965. He becamefull Professor in 1976, andhas served asChairman of the department's concen-tration in electronics, computers, an(]

systems, and as a member of MIT'sCommission on Industrial Productivity.Professor Staelin's research interestsinclude electromagnetic systems and

signal processing, remote sensing, ra-dioand optical astronomy, video imageprocessing, and manufacturing. He is aFellow of the IEEE and the AmericanAssociation for theAdvancement of Sci-ence. (Photo byJohn F. Cook)

Dr ThomasF Weiss (SM 59, I'M) '63),Professor of Electrical and Bioengi-neering, has been named corecipient

of the Best Engineering SoftwareAward presented by the EDUCOM/Na-tional Center for Research to improvePnstsecondary Teaching and Learningin the 1990 Higher Education SoftwareAwards competition. MIT staff memberGiancarlo Trevisan and graduate stu-dent David Huangshared the awardwith Professor Weiss for developingsoftware that allows users to demon-strate the Hodgkin-Huxleymodel ofnerve cell membrane response to elec-trical simulation for different environ-mental variables. The EDUCOM/NCRIP-TAt. Higher Education Software Awards

program acknowledges developers and

faculty whose efforts exemplify the bestinnovations in academic software andcurriculum. Professor Weiss and hiscollaborators received the award at theEDUCOM conference in Atlanta, Geor-

gia, in October. (Photo byJohn F. Cook)

Dr.JesüsA. delAlamo was appointedto the ITT Career DevelopmentProfessorship in the Department ofElectrical Engineering and ComputerScience. Professor delAlamojoined theMIT faculty in 1988, after working atNippon Telegraph and Telephone Cor-

poration inJapan. AStanford Universitygraduate, his research interests include

high-performance semiconductorde-vices for microwave andoptical com-munications, and molecular beam epi-taxy of Ill-V heterostructures for thesedevices. Professor delAlamo is the fifth

appointment to theTn' chair, whichwas established in 1980 by a grant fromthe International Telephone andTele-

graph Corporation to provide supportfor promising junior faculty in the de-

partment.(Photo byJohn F. Cook)

Dr.Jacqueline N Hewitt (PhD '86), As-sistant Professor of Physics, received a

five-year Davidand Lucile PackardFoundation Fellowship in October.Since 1988, the Packard Foundation hasawarded scienceand engineering fel-

lowships to support basic scientific re-search conducted by talented youngfaculty members and to encourage fel-lows to continue productive universitycareers. Professor Hewitt wasamongtwenty faculty members chosen fromuniversities throughout the UnitedStates. She was cited for demonstratingunusual creative ability in her researchwork, which involves radio astronomyand astrophysics in RLE's Radio Astron-

omy Group (see page 5). ProfessorHewitt has recently received the Annie

Jump Cannon Award in Astronomyfrom the American Association of Uni-

versity Women and an Alfred I'. SloanFoundation Research Fellowship.(Photo bp John Cook)

Dr Donald K Eddinglon was promot-ed to Principal Research Scientist in the

TENURE GRANTEDCongratulations to twoRLEfaculty memberswhowere

granted tenure in 1990:

Dr.James G. Fujimoto (SB '79, SM'81, PhD '84), Associate Professorof Electrical Engineering and Com-

puter Science. Professor Fujimotojoined the MITfaculty in 1985 andis a member of RLE's Optics andDevices Group. Professor Fujimotostudies femtosecond optics and its

applications in quantum electron-ics and laser medicine. His re-search group has produced laser

pulses as short as afew wave-

lengths of light, and has used themto investigate the ultrafast dynam-ics in optoelectronic materials anddevices, lie was a National ScienceFoundation (NSF)Graduate Fellowfrom 1972-82, and received an NSFPresidential Young InvestigatorAward in 1986. Recently, Professor

Fujimoto was named corecipientof the 1990 National Academy ofSciences Award for Initiatives inResearch by AT&T Bell Laborato-ries (see currents, vol. 3, no. 2).Professor Fujinioto is also a Visit-

ing Lecturer in Ophthalmology atHarvard Medical School and a con-sultant for Lincoln Laboratory. Heis a member of the American Asso-ciation for the Advancement of Sci-ence, the American Physical Soci-

ety, the Optical Society ofAmerica,

Sigma Xi, Tau Beta Pi, and Eta

Kappa Nu. (Photo byJohn i Cook)

Dr. PeterL HageLctein (SB/SM '76,PhD '81), Associate Professor ofElectrical Engineering and Com-

puter Science. Before joining theMIT faculty in 1986, Professor Ha-

geistein wasa Principal Project Sci-entist at the Lawrence LivermoreNational Laboratory. In addition to

receiving a tenured faculty posi-tion, Professor l-iagelstein has beennamed corecipient of the 1990Award for Excellence in Plasma

Physics Research presented by theAmerican Physical Society's Divi-sion of Plasma Physics. Professor

1-lagelstein shared this honorwithhis collaborators: Dr. Mordecai D.Rosen, Dr. Dennis I. Matthews, Dr.E. Michael Campbell, all ofLaw-rence Livermore Laboratory;andDr. Szymon Suckewer of Princeton

University. The Society cited the

group for the first demonstrationof a soft x-ray laser, achieved

through pioneering laser target de-

sign, theoretical modeling of thestates of highly ionized atoms in la-

ser-produced plasmas, and novel

spectroscopic diagnostics ofsuch

plasmas." The award was present-ed at a meeting of the Society's Di-vision of Plasma Physics in Cincin-nati, Ohio, in November. (Photo byJohn F. Cook)

Auditory Physiology Group. A graduateof the University of Utah (BSEE '73,PhD '77), Dr. Eddington has been a Re-search Scientist with RLE since 1983.He conducts fundamental research andexperimentation on the developmentof auditory neuroprostheses, and is Di-rector of the Cochlear Implant Re-

Professor Emeritus andSenior

LecturerJoseph CRLicklider, 75,died June 26, 1990, following com-plications from asthma. Born in St.Louis, Missouri, and educated atWashington University and theUniversity of Rochester, ProfessorLicklider came to MIT in 1950. Pre-viously, he had worked at HarvardUniversity's Psychoacoustics Labo-ratory, where he discovered that"clipped speech" (produced bylimiting the amplitude of speechwaves) was 70-90 percent intelligi-ble. Professor Licklider's back-ground was in the psychology ofcommunications, and he played amajor role in stimulating linguis-tics research at MIT while contrib-uting to the study of biological as-pects of communication. Helectured on the neurophysiologyofvision and hearing, the percep-tion of speech, and the presenta-tion and assimilation of informa-tion. At MIT, lie was affiliated with

search Laboratory at the MassachusettsEye and Ear Infirmary (see currents,vol. 3, no. 1). Dr. Eddington is also anAssistant Professor in the Departmentof OtologyandLaryngology at HarvardMedical School. (Photo byJohn F.Cook)

IN MEMORIAM

RLE, the Acoustics Laboratory, theDepartment of Electrical Engineer-ing and Computer Science, and theDepartment of Economics and So-cial Sciences. He was also co-headof Lincoln Laboratory Group 31.From 1957-62, he worked at Bolt,Beranek, and Newman, where hebecame a vice president. In 1960,he published the seminal paperMan-Machine Symbiosis, whichproposed the concept of a greaterrole for computers; people andmachines could interact to solveproblems, not only to performmathematical calculations. Profes-sor Licklider was instrumental indeveloping computer time-sharingresearch at MIT, and encouragedthe start of computer science stud-ies in the Electrical EngineeringDepartment. His career also in-cluded tenures at the Defense De-partment's Advanced ResearchProjects Agency, the agency's infor-mation Processing Techniques Of-fice, and IBM Corporation. He re-turned to MIT and was appointedAssociate Director of Project MAC(now the Laboratory for ComputerScience), where he subsequentlybecame Director. Professor Lick-lider retired from the MIT facultyin 1985. Professor Licklider was aformer president of the AcousticalSociety ofAmerica. In March 1990,he received the Common WealthAward for Distinguished Servicefrom a Delaware humanitariantrust for his work in computernetworking and the interaction be-tween humans and computers.(Photo by Koby-An/upit)

alumni notesFrankAmoroso (SB '56, SM '58) has re-tired after 16 years with Hughes Aircraft.He resides in Santa Ana, California, andkeeps busy by serving as an expert wit-ness in patent litigations, publishing re-search papers in the field of data mod-ulation, and writing non-fiction maga-zine features (especially on scubadiving).Wilbur B. Davenpor4 Jr. (SM '43, ScD'50) sends his regards from Sunriver,Oregon. He taught at the University ofHawaii during the last spring semester("a freshman computer programmingcourse based on C and a junior courseon Fourier stuff using Oppenheim andWillsky"), while his wifeJoan was a Do-cent at the Honolulu Academy of Arts.

JosefEislnger (PhD '51) is Professor ofBiophysics at the Mount Sinai School ofMedicine in New York, where his spe-cial interest is fluorescence microscopy.Previously, lie was at Bell Laboratoriesfor 30 years.Norman E Gaut (SM '64, PhD '67),Chief Executive Office and President ofPicturetel Corporation of Peabody, Mas-sachusetts, was featured in a business ar-ticle about the image processingcompany in The Boston Sunday Globe,September 23, 1990.

Michael Helke (PhD '71) has workedsince 1975 at the United Nations in NewYork, where he served as a Senior Politi-cal Affairs Officer. Most recently, he hasrelocated to England, where his wife is aBritish diplomat.

Jay W. Lathrop (SB '48, SM '49, PhD '52)is Professor Emeritus of Electrical andComputer Engineering at Clemson Uni-versity. He retired in 1989, and residesin West Union, South Carolina.

IrwinL Lebow (SB '48, PhD '51) is aconsulting engineer in Washington, DC,and has written a book, TheDigital Con-nection, published by W. H. Freemanlast summer. He was previously a ChiefScientist at DCA in Washington.Lawrence R. Rabiner (SB/SM '64, PhD'67), Head of the Speech ResearchDepartment at AT&T Bell Labs in Murray[fill, New Jersey, was elected to the

RLE alumnus Dr. William B. Lenoir

(BS 61,MS '62, 1111D'65), a former as-tronaut, is the Associate Adminis-trator for NASA's Office of SpaceFlight. Dr. Lenoir is responsible forthe development, procurement, and

operation of the Space Shuttle and

Space Station; management of all U.S.

government civil launch capabilities;U.S. Spacelab operation; and plan-ning for future space flight, transpor-tation, and system engineeringprograms. Dr. Lenoir develops and

implements policy for all Space Shut-tle System, Space Station, and U.S.

launch activities, lie is also in chargeof the Johnson, Kennedy, Marshall,and Stennis space centers.

A native of Miami, Florida, Dr.Lenoir received his degrees fromMIT's Department of Electrical Engi-neering and Computer Science. Hewas a Ford Foundation post-doctoralfellow and served two years on theMIT faculty as an Assistant Professorof Electrical Engineering.

Dr. Lenoir's graduate researchwas performed under Professor AlanH. Barrett in RLE's Radio AstronomyGroup. During the 1960s, ProfessorBarrett successfully showed that mi-crowave atmospheric sensing was

RLE's RIGHT STUFF

Dr. William B. Lenoir (Photo courtesy ofNASA)

possible. As part of his research un-der Dr. Barrett, Dr. Lenoir designed a

60-gigahertz atmospheric sensing mi-

crowave receiver to remotely sensethe temperature profile of the Earth's

atmosphere at different altitudes. Dr.Lenoir worked with Sponsored Re-search Technical StaffJohn W. Barrettto deploy this instrument package onboard a high-altitude (125,000 feet

average altitude) helium balloonlaunched from the National Centerfor Atmospheric Research in Pales-tine, Texas. These experiments re-sulted in the newinstruments used inthe Nimbus series of NASA satellites,which further evolved into elementsof today's weather forecasting satel-lite system of the National OceanicandAtmospheric Administration.

Dr. Lenoir was vice presidentanda member of the board of direc-tors of Booz, Allen & Hamilton Inc.,Bethesda, Maryland, and also man-

aged that company's Space SystemsDivision until he was selected for hisNASA appointment. Prior to joiningBooz, Allen, Dr. Lenoir was chief ofthe mission development group inthe Astronaut Office at NASA's John-son Space Center in Houston. He di-rected and managed all astronautactivities concerned with mission de-

velopment and payload operations.Dr. Lenoir flew in space asa mis-

sion specialist on Shuttle MissionSTS-5, the first operational flight ofthe Space Transportation System, inNovember 1982. lIe was the first

spaceborne launch director to de-

ploy the first communications satel-lite from the shuttle.

National Academy of Sciences.

Robertj Shiliman (SM '71, PhD '74),founder and CEO of Cognex Corpora-tion in Needham, Massachusetts, wasnamed New England's 1990 Entrepre-neur of the Year in High Technology.The award was cosponsored by Ernst &

Young's Entrepreneurial Services Divi-sion, Inc. magazine, and Merrill Lynch.Dr. Shillman was chosen from morethan 150 New England entrepreneursand cited for his company's success inthe field of machine vision.

Lamar Washington Jr., (SB '56) sendshis reminiscences of his colleagues at

RLE, and writes of his 12 children and21

grandchildren. He resides in Menands,New York.

We welcome news of accomplishmentsfrom RLE graduates. Letters may he ad-dressed to:

Professor Jonathan Allen, DirectorResearch Laboratory of ElectronicsRoom 36-413Massachusetts Institute of Technology77 Massachusetts Avenue

Cambridge, MA 02139

Telephone: 617-253-2509Telefax: 617-258-7864

SHORT CIRCUITS

The staff of currentswould like to notethe following cor-rection to the Spring1990 issue:

The 1958 photograph on page 17

mistakenly identified Visiting Sci-entist Saburo Muroga as ProfessorWilbur B. Davenport, Jr.

Thanks to both Professor Wilbur

Davenport, who checked the error,and to Professor Robert Fano, who

correctly identified Dr. Muroga.

History ofRadio Astronomyat RLE

Ca. 1945Radiation Laboratory roof-top crewuses 'ShaggyDog" microwave radiom-eter equipment pointedat the sun tomeasure water absorption by the atmo-

sphere. Atop Building 20 (from left).- Ed-ward R. Beringer, Robert L. Kyhi, ArthurB. Vane, andRobert H. Dicke. (Photo

from Five Years at the Radiation Labora-

tory)

1952Professor Malcom W. P- "Woody"Strandbergplayedan active role in ap-plying microwave techniques to labo-ratory problems andcontributed to the

understanding ofphysicc in masersand in oxygen absorption- Here, heconducts an experiment oftheZeeman

effect in the rotational spectra ofmole-cules. (Photo by Benjamin Diver)

C

(Prom left): Graduate studentSanderWeinreb, Professor Alan IL Barrett, Dr.M. Littleton Meek's, andgraduate stu-dentjohn C Henry were responsibleforthe detection, identification, andmeasurementofthefirst molecularmatter everfoundby radio astronomytechniques in interstellar space. Posi-tive radio identification ofoxygen-hy-drogen molecules (called the hydroxolradical or OH radical) enabled radioastronomers to chart the distributionandabundanceof01-i as well as oxy-genandhydrogen in the galaxy andcontributed to agreater understand-

ing of thefundamental astrophysicalinteractions that leadto theformationofgalaxies. (Photo courtesy MITMuseum)

1967

Professor DavidH. Staclin on locationat White Mountain, California, con-ducts black body radiation experi-mentsin theJune snow. The experi-mentsmeasured cosmic backgroundradiation at 8-millimeter wavelengths.(Photo by Bernard ! Burke)

1965

On location at the National CenterforAtmospheric Research in Palestine, Tex-as.A launch crewprepares apparatusthat ispart ofgraduate student WilliamB. Lenoir's research-a 60-gigahertzatmosphericsensing receiver (inset).Once loftedairborne by balloon, the re-ceiver remotely sensed the temperatureprofile at different altitudes. These ex-

periments evolved into the Nimbusse-ries ofNASA satellites, which later be-camepart ofthe National Oceanicand

Atmospheric Administration's satelliteweatherforecasting system. (RLEfilephoto)

Graduate studentJoe W. Waters records informa-tionfrom a53-gigahertz atmospheric temperaturesounding radiometer aboard aNASA high-altitudeConvair990test aircraft. (RLRfiIephoto)

1971

Professor BernardF. Burkeflags locations on theglobe that represent thefive major VLBJ stations in

operation at that time: Green Bank West Virginia;Haystack Observatory, Massachusetts; Hatcreek atthe University of California in Berkeley; Onsala atChalmers University in Sweden;andOwens Valley atthe California Institute ofTechnology. (Photo byJohn F. Cook)

1971

Research Staffmember D. CosmoPapa (left)andgraduate student Kai-shuelam useRLE'S anechoic chamber to test the radi-ationpatterns ofa 53-gigahertz microwaveantenna. (Photo byJohn F. Cook)

Arustic view ofthe NationalRadioAstronomy Observatory in GreenBank West Virginia. Thisfacility was used by man)'RLEstudentsforearly VLBJ operations andto compile the MIT-Green Bank Survey. The140-footparabolic antenna collapsed in November 1988 under

heavysnow,anda newantenna isplannedfor the site. ('Photo by Ber-nardF. Burke)

1975

RLRgroupperforms outdoormainte-nanceon equipment used in experi-ments involving a three-element inter-

ferometerforthe aperture synthesis ofradio sources. These experiments weretheprecursorforVLBI development atshort wavelengths. Research staffmem-

berD. CosmoPapa ascends ladderwhile colleagues look on (from left):Professor Bernard !' Burke, graduatestudents Daniel C. StancilandBarryR.Allen, andresearch staffmemberJohnW. 'Jack" Barrett. (Photo byJohn F.Cook)

1977

ProfessorsAlan H. Barrett (right) and

Philip C'. Meyers extend the radio as-

tronomy techniques that detect mole-cules in space to the diagnosis ofbreastcancer in humans. Their technique,called microwave thermography, usesmicrowave radiometers to measure mi-crowaves emitted by human tissue andsense abnormal temperatures. (Photo

byJohn 1 Cook)

1977

Checking an instrument that is the di-rectforerunner oftoday c operationalsatellite microwave atmosphericimagers used by the National OceanicandAtmospheric Administration. From

left: Professor David II. Staelin, gradu-ate student Paul G. Steffes, andre-search staff memberD. 6'osmo Papa.(Photo byJohn F Cook)

UPDATES:Collegium

The RLE Collegium was established in1987 to promote innovative relation-ships between the Laboratory and busi-ness organizations. The goal of RLE'sCollegium is to increase communica-tion between RLE researchers andindustrial professionals in electronicsand related fields.

Collegium members have the op-portunity to develop close affiliationswith the Laboratory's research staff andcan quickly access emerging resultsand scientific directions. Collegiunibenefits include access to a wide rangeof publications, educational video pro-grams, PIE patent disclosures, semi-nars, and laboratory visits.

The RLE Collegium membershipfee is $20,000 annually. Members ofMIT's Industrial Liaison Program canelect to transfer 25% of their JLP mem-bership fee to the RLE Collegium. Mem-bership benefits are supported by theCollegium fee. In addition, these fundswill encourage new research initiativesand build new laboratory facilitieswithin RLE.

For more information on the RLECollegium, please contact PIE Head-quarters or the industrial Liaison Pro-gram at MIT.

Publications

PIE has recently published the follow-ing technical reports:

A Fault-Tolerant MultiprocessorAr-

chitectureforDigital Signal Process-

ingApplications, by William S. Songand Bruce R. Musicus. PIE TR No. 552.February 1990. 143 pp. $15.00.

A Receiver-Compatible Noise Reduc-

l'rojessor Srinivas Devadaspresentsa talkon logic synthesis, testing, and verf1ca-lion at RLE's Computer-AidedDesign Re-view, heldSeptember20, 1990. TheJacul-lv andstudents ofRLE's Circuits andSystems Group invited colleaguesfromindustry to attend this one-day meeting,which servedas aforum on computer-aided design. Topics included: logic and

finite-state machinesynthesis, andsynthe-sisfor testahilitv parallel, serial circuit,and device simulation algorithms; and

performance-driven synthesis.

tion System, by Matthew M. Bace. PIETR No. 553. April 1990. 113 pp. $14.00.

Adaptive Frequency Modulation forSatellite Television Systems, by JulienPlot. PIE TR No. 554. April 1990-153PP. $15.00.

Syllable-based Constraints on Prop-erties ofEnglish Sounds, by Mark A.Randolph. PIE TR No. 555. May 1990.219 pp. $17.00.

Estimation and Correction ofGeo-

metric Distortions in Side-Scan Sonar

Images, by Daniel T. Cobra. PIE TR No.556. May 1990. 141 pp. $14.00.

Femtosecond Thermomodujation

Measurements ofTransport and

Relaxation in Metals andSupercon-ductors, by Stuart D. Brorson. RLE TRNo. 557. June 1990. 171 pp. $17.00.

Channel Equalization and Interfer-ence Reduction Using ScramblingandAdaptiveAmplitude Modulation,

by Adam S. Tom. RLE TR No. 558. June1990. 122 pp. $14.00.

Transform/SubbandAnalysis and

Synthesis of Signals, by David M. Bay-Ion and Jac S. Lim. PIE TR No. 559. June1990. 37 pp. $6.00.

In addition, RLE Progress Report No.132 is available at no charge. The Prog-ress Report, covering the period Janu-ary through December 1989, contains astatement of research objectives and asummary of research efforts for eachPIE research group. Faculty, staff andstudents who participated in theseprojects and sources of funding areidentified at the beginning of eachchapter. Current PIE personnel is alsolisted.

Also available at no charge is the RLEPublications UpdateJanuary -June

1990.

PIE welcomes inquiries regarding ourresearch and publications. Please con-tact:

Barbara PasseroCommunications OfficerResearch Laboratory of ElectronicsRoom 36-412Massachusetts Institute of TechnologyCambridge, MA 02139telephone: (617) 253-2566telefax: (617) 258-7864

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