More than a year’s worth of expensive data used to trace the shape of the Milky Way galaxy could become worthless as a result of today’s closure of U.S.-based radio telescopes because of the government shutdown.“Holy cow, this is really bad,” radio astronomer Mark Reid said when informed by ScienceInsider that the telescopes were going offline. “If they don’t operate the telescopes, it could mean a year’s worth of data becomes useless.” And it would be a costly loss, he adds, estimating that the data cost $500,000 to collect.Reid is a U.S. government employee who works for the Smithsonian Astrophysical Observatory, part of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. Like hundreds of thousands of other federal workers, he’s been at home since the shutdown began on Tuesday. Meanwhile, he’s been trying to use some of his time off productively, thinking about his collaborative work with an international team on measuring and mapping the great spiral arms of the Milky Way.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)Twice a year, Reid and his colleagues use the Very Long Baseline Array (VLBA)—a string of 10 sensitive radio telescopes stretching 8600 kilometers from Hawaii to the Virgin Islands and New England—to help make measurements from Earth to massive gas clouds surrounding about 50 newborn stars in the galaxy. The VLBA measurements, made in the spring and fall, allow the team to calculate distances to the stars and construct a map of the galaxy. The map’s accuracy, however, depends on comparing three sets of VLBA measurements taken over 18 months.Today’s shutdown of the National Radio Astronomy Observatory (NRAO), a National Science Foundation-funded organization that runs the radio telescopes, threatens that accuracy. “If you miss one of these observations, you basically have to start over the next season,” Reid says.About one-half of this year’s data has already been collected, but the team had been expecting to use the VLBA to measure the distance to 25 other stars this month. “The VLBA is really the only array we can use,” so if they can’t take the data this month, the team won’t be able to compare the data with the past two cycles.All is not lost if the U.S. Congress can agree on a way to fund the government by the middle of October. It will take several days to get the telescopes up and running, NRAO officials say. Then, astronomers may be able reschedule some of their planned VLBA measurements, Reid says, but with some loss of accuracy because Earth will have passed an optimal point in its orbit around the sun.Reid says he’s stunned by the development. “I thought NRAO was safe” because it was not a government agency, he says. “I never even thought about this, but there’s nothing I can do about it either.”You can see our complete shutdown coverage here.