Research Opportunities fr om SoundingRocketsat JohnsHopkins University

StephanR. McCandlissThe JohnsHopkins University

Henry A. Rowland Department of Physicsand Astronomy3400North Charles Street

Baltimor e,Maryland 21218stephan@pha.jhu.edu

http://www.pha.jhu.edu/˜stephan/phone410.516.5272

fax 410.516.5494July 18,2001

1. Research Opportunities fr om SoundingRocketsat JohnsHopkins University

It is T-1 minute to launch. The all-systems-gohasbeengivenandJohnsHopkinsUniversitygraduatestudentKevin Franceis feeling the pressure.The fi-nalhurdlein thepreparationfor launchof NASA/JHUsounding rocket number 36.198 UG from LaunchComplex 36atWhiteSandsMissileRange,New Mex-ico hasbeenpassed.Now all that remainsis to carryout the mission,a spectroscopicstudy of the far ul-traviolet scatteringpropertiesof interstellardustin thereflectionnebula IC 405.

Kevin hopes that this observation will revealclues into what keepsthis cloud from forming intostars by studying the interplay between the far-ultraviolet radiationfield, andthedust,moleculesandatomsthatcomprisethecloud. It is a feedbacksystemthatoperatesmuchlikea thermostatregulatingthere-leaseof energy generatedasthecloudof gasanddustattemptsto collapseinto protostars.This cloudseemsto bedevoid of starformationandhewantsto under-standwhy.

Theelapsedtime for themissionwill be900sec-onds and the events are tightly scripted. The firststageTerrierboosterwill burnfor 6 secondslifting therocket to analtitudeof 3 kilometers.ThenthesecondstageBlack Brantwill kick in, propellingthepayloadto analtitudeof 60 kilometersanda velocityof Mach7. At this point thehalf ton payloadandBlack Brantmotorwill separateandthepayloadwill follow a bal-listic trajectoryto anapogeeof 300kilometersunderthe coarsepointing control of the onboardguidanceand navigation systemthat will usecold gasjets tosteerthetelescopeto acquirethetargetnebula.

Between separation and acquisition severaleventswill occur:Thetelescopedooropens,theneb-ulaviewingcameraturnson,thespectrographslit dooris openedand the high voltage to the spectrographdetectoris activated. All theseeventswill be moni-toredon the groundvia a real-timetelemetrystream.Thetargetwill beacquiredatT+150secondsatwhichpoint the final job, the precisionpointing of the tele-scope,will be handedover to Kevin. He will standin front of a controlpanelshowing a real-timeimage

of thenebula andperformmaneuverswith pitch, yawandroll controls,notunlikethoseonyourtypicalcom-putergame. For 350 secondshis job will be to steerselectedportionsof the nebula into the spectrographslit, amere1/3of amillimeterwideand6 millimetershigh, andhold it there.Thepointingwill beoverseenby his advisorwhosejob is to provide a real-timeas-sessmentof thespectrographcountrate,keeptrackoftheremainingtime, andoffer adviceon whereelsetopointwithin thenebula.

This ultimatetaskis the big payoff, the acquisi-tion of theprimarysciencedata,which will becomeatopicof analysisfor hisPh.D.thesis.It hasbeenmadepossibleby monthsof preparationandattentionto amyriad of tasksall of which mustbe completedsuc-cessfullyby the launchprovider andpayloadteams.Therehasbeennoroomfor error, which is why Kevinis now feelingthepressure.He is thefinal link in theprocessandheis determinednot to betheweakest.

Foundedin 1961by G.H. DiekeandW. G.Fastieundersupportfrom NASA, the soundingrocket pro-gram at JHU hasprovided many graduatestudents,like Kevin, the opportunity to usesoundingrocket-bornetelescopesandspectrographsto makeuniqueas-tronomicalandatmosphericobservations. The groupspecializesin the developmentof spectroscopicin-strumentation;a naturaloutgrowth from thelegacy ofdiffractiongratingresearchledby ProfessorHenryA.Rowlandof JHU at theendof thenineteenthcentury.Most of theJHU’s currentsuiteof rocket-bornespec-trographswork in the900-2000Angstromwavelengthrangewheretheearth’satmosphereis stronglyattenu-atingandobservationscanonly bemadeby soundingrocketsor orbiting telescopes.Pastmissionsincludeobservationsof earth’saurorae,severalcometsinclud-ing Hale-BoppandHalley, Jupiter, Venus,Io’splasmatorus,a numberof hot starsandnebulae,andthefirstultraviolet spectrumof thequasar3C273.

In theprocessof designingtheseexperimentsthegraduatestudentsreceive hands-ontraining in optics,mechanics,electronicsandflight supportsystems,inaddition to learning the scientific conceptsof theirchosendiscipline. The JHU payloadteamincludesaprojectengineerandPh.D.projectscientistwho pro-vide experience,direction and corporatememoryto

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thestudent.Participationin theprogramalsoincludesundergraduates,who assistthe graduatestudent,en-gineerandprojectscientistwith thepreflightpayloadassemblyandcalibrationefforts.

Thesuborbitalprogramis uniquein allowingpar-ticipation in all phasesof a spacemission,from con-ceptto final analysisof thedata,on a time scalecom-mensuratewith the length of a graduateeducation.Over the courseof the program’s existenceat JHUtherehave been72 rocket launches,and31 Ph.D.dis-sertationshave beenbasedwholly or partly on workdoneunderthisprogram.Graduateandundergraduatestudentswhohaveparticipatedin pastsoundingrocketprojectsare highly prized by the space-flightcom-munity, andhistorically have beenhighly soughtaf-terby nationallaboratories,industryandacademiaforthedevelopmentof thenext generationof astronomi-cal andatmosphericspacemissions.TheJHU sound-ing rocket programhasbeenintimately involvedwithsupportinga numberof relatedNASA programs,in-cludingtheApollo 17Ultraviolet SpectrometerExper-iment,theInternationalUltraviolet Explorer, theHop-kins Ultraviolet Telescope,the Hubble SpaceTele-scope,andtheFarUltraviolet SpectroscopicExplorer.It is in supportof projectslike thesewheretheworthof thesoundingrocketprogramexceedstheshorttermsciencereturnof anindividualmission.

Soundingrocket flights areusedto validatenewinstrumentalconceptsand to develop to a state offlight readinessinstrumentationdestinedto be flownon future long duration free-flyer missionslike thelaunchopportunitiesofferedby NASA’sExplorerpro-gram. Announcementsof Opportunity for MediumandSmallExplorersoccurata rateof aboutoneeveryyear, with typically two missionsselectedfor eventualflight. Thecompetitionfor theselaunchopportunitiesinvolvesthewriting of proposalswith compellingsci-encegoalsanda clearly definedtechnicaland man-agementplan. Suchwork requiresa highly trainedworkforce,knowledgeablein the waysof translatinghigh level sciencegoalsinto realisticmissionrequire-ments. The skill mix requiredby this workforce iswell matchedby studentstrainedin thewaysof rock-etry, many of whomgoonto proposemissionsof theirown devising.

But let us get back to Kevin. The count pro-ceedsandthe payloadis launched.All systemsper-form nominallyandthetargetis acquiredonschedule.Kevin managesto observe threedifferent regions inthenebula within his allotted350seconds.Thedoorsclose, the parachuteopensand at aboutT+900 sec-ondsthe lossof signaloccurs,indicatingthepayloadhastoucheddown below the horizonat a point some80kilometersup-range.Thereit will sit until theheli-copterscometo pick it off thedesertfloor andreturnit to thepayloadprocessingarea.Thecrew is ecstatic.Thereis muchrejoicing.Playbacksof theprimarysci-encedatagoeson into thenight, curtailedonly by thewearinessof thegroundstationcrew (whohaveseenitall before)andtheneedto geta little sleepbeforethehelicopterarrivesto takethepayloadrecoveryteamtothelandingsite.Everyonesleepssoundly, for thefirsttime in months,andat first light Kevin climbsaboardthe Huey that takes him and selectmembersof theteamout on recovery. Everythingis in goodshape;infact,thetelescopeis still undervacuumwhenit arrivesbackat the processingarea. Now begins the processof packingup the ton of supportequipmentfor ship-mentback to BaltimorewhereKevin will engageinpost-flightcalibrationsandanalysisof his data.

Kevin is not sureof what the analysiswill tellhim, but he knows onething after scanningtheplay-backs– the dustwasblue. Onehundredtimesbluerthan the dust observed by the sameinstrumentin adustcloudrife with starformation. Maybethis is thekey. Only timewill tell.

Dr. StephanR. McCandlissis a ResearchScien-tist with theHenryA. RowlandDepartmentof PhysicsandAstronomyat the JohnsHopkinsUniversity. Hea Co-Investigator with the JHU Sounding Rocketgroup, responsiblefor the design,procurement,fab-rication, calibration,andintegrationof spectroscopictelescopeexperimentsinto soundingrocket deliverysystemsprovidedby theNASA SoundingRocket Op-erationsContractor(NSROC) at the Wallops FlightFacility, Virginia. For moreinformationcanbefoundat http://www.pha.jhu.edu/groups/rocket/ and by fol-lowing thelinks therein.

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2. Picture Caption

Right to left, JHUgraduatestudentKevin France,JHU projectengineerRussPelton,NSROC mechan-ical engineerRobertRyan, and NSROC mechanicaltechnicianLarry Lockhart.

Pictureinformation.NAWCWD WS-SCN-01-0607-013TerrierBlack BrantRecoveryOperationsTerrierBlack-BrantImpactSite

PhotoDate:02/10/2001PhotographerR. VanceU.S.Army PhotographWhiteSandsMissile Range,N.M. 88002Publicationorcommercialuseof thismaterialrequiresreleaseby theU.S.ARMY PublicAffairsOfficer. (Goto http://www.wsmr.army.mil/paopage/pao.htmforfurther information on securingpicture publicationrelease.)Credit: U.S.Army

3. Nugget

Aimee – Whenever we get a nice result NASAHQ likesto hearaboutit. On thenext pageis a littlemini posterI put togetherattemptingto describeourresultto themsuccinctly. It’ s a little technical.I don’tknow if it is of any useto you.

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