Poised to be­gin trip be­yond the Earth

Webb Space Tele­scope en­ters fi­nal prepa­ra­tions

Baltimore Sun - - FRONT PAGE - By Scott Dance

GREENBELT — Twenty years ago, sci­en­tists laid out a wish list for a suc­ces­sor to the Hub­ble Space Tele­scope, en­vi­sion­ing a de­vice that could deepen knowl­edge of the ori­gins of the uni­verse.

To­day, an in­stru­ment be­fit­ting that de­scrip­tion is poised for its fi­nal tests at the NASA God­dard Space Flight Cen­ter.

The heart of the James Webb Space Tele­scope — a 22-foot-tall golden mir­ror at­tached to a set of four cam­eras and spec­tro­graphs — has been as­sem­bled inside a mas­sive clean room on the God­dard cam­pus.

Over the next four months, en­gi­neers will ex­pose it to noise and vi­o­lent vi­bra­tions — like those it will likely ex­pe­ri­ence dur­ing a launch that’s less than two years away.

The tests are the tele­scope’s fi­nal steps at the Prince Ge­orge’s County in­stal­la­tion, though a long list of prepa­ra­tions re­mains, in­clud­ing work to ready the Bal­ti­more com­mand cen­ter that will op­er­ate it from a mil­lion miles away.

The tele­scope is next bound for Hous­ton in Fe­bru­ary for more test­ing, Los An­ge­les next sum­mer for its fi­nal assem­bly, then a launch pad in South Amer­ica in 2018.

At an event Wed­nes­day in Greenbelt, NASA Ad­min­is­tra­tor Charles Bolden cel­e­brated the progress at God­dard.

“This was a long time com­ing be­cause it’s so com­plex,” Bolden said.

God­dard has led de­vel­op­ment of the Webb tele­scope since its in­cep­tion in the late 1990s, while NASA chose Bal­ti­more’s Space Tele­scope Sci­ence In­sti­tute to over­see its sci­en­tific mis­sion and op­er­a­tions in 2003.

Over that time, the $8.7 bil­lion project has sur­vived cost and sched­ule over­runs and four pres­i­den­tial ad­min­is­tra­tions to get to where it is to­day.

Bolden and col­leagues ac­knowl­edged many tech­ni­cal and lo­gis­ti­cal hur­dles re­main but said they’ve learned from the tra­vails of the Hub­ble, which was found to have a ma­jor flaw in its pri­mary mir­ror just weeks af­ter its launch into or­bit.

The les­son: “If you re­ally care about some­thing, you bet­ter mea­sure it at least twice,” said John Mather, a se­nior as­tro­physi­cist at God­dard and the tele­scope’s project sci­en­tist. “We built our en­tire project around that.”

Webb was de­signed to see what Hub­ble and ground-based tele­scopes can­not. Its mir­ror is seven times the size of Hub­ble’s, al­low­ing it to see far­ther. It also can ob­serve in in­frared light. Hub­ble has lim­ited abil­ity to ob­serve at that wave­length, and Earth’s at­mos­phere blocks most in­frared light from reach­ing even the most pow­er­ful moun­tain­top ob­ser­va­to­ries.

Sci­en­tists hope Webb will al­low them to see how gal­ax­ies, plan­ets and stars formed in the ear­li­est days of the uni­verse. Be­cause light trav­els at a con­stant speed, what ap­pears the far­thest from Earth also takes the longest to get here.

In­frared ob­ser­va­tions also could of­fer more il­lu­mi­nat­ing views of plan­ets out­side the so­lar sys­tem.

The tele­scope will de­tect gases such as car­bon diox­ide and meth­ane more eas­ily, and could show if a planet has enough wa­ter va­por in its at­mos­phere to sug­gest it con­tains oceans.

“We are open­ing up a whole new ter­ri­tory of astron­omy,” said Mather, who won a No­bel Prize in 2006 for work ob­serv­ing echoes of the Big Bang across the cos­mos.

The Webb tele­scope’s hon­ey­comb­shaped mir­ror is pow­er­ful enough to spot a bee buzzing from a dis­tance as far as the moon is from Earth, he said.

“I don’t want to ex­ag­ger­ate, but that’s be­yond a mir­a­cle as far as my per­spec­tive is con­cerned,” Mather said. Charles Bolden, left, NASA ad­min­is­tra­tor, lis­tens as John Mather, se­nior project sci­en­tist of the James Webb Space Tele­scope, an­swers ques­tions from the news me­dia at NASA’s God­dard Space Flight Cen­ter. Be­hind them is the gold-cov­ered pri­mary mir­ror.

Over the next few months, the tele­scope will be carted out of the mas­sive clean room inside a three-story tall tent to un­dergo its fi­nal tests at God­dard. It will be rat­tled atop plat­forms ca­pa­ble of ex­pos­ing it to forces 10 times stronger than grav­ity, and sealed inside a sound chamber to be blasted with noise as loud as a rocket en­gine.

El­e­ments of the tele­scope have al­ready gone through such tests, but en­gi­neers have to be sure the as­sem­bled ap­pa­ra­tus can sur­vive its ride aboard a Euro­pean Space Agency rocket launch­ing from French Guiana.

“It — hope­fully — is a for­mal­ity,” said Ja­son Hy­lan, lead me­chan­i­cal en­gi­neer for the tele­scope’s suite of in­stru­ments.

As­sum­ing all goes well, the tele­scope will be shipped in Fe­bru­ary to the John­son Space Flight Cen­ter in Hous­ton, where it will un­dergo a 90-day test in frigid tem­per­a­tures.

In July or Au­gust, it will move on to Northrop Grum­man fa­cil­i­ties in Cal­i­for­nia, where it will take its fi­nal shape atop a sil­very sun shield the size of a tennis court. All of the com­po­nents will even­tu­ally be folded up to fit atop the rocket.

Once it launches, it will be six months be­fore the tele­scope reaches its des­ti­na­tion in space, and then an­other two weeks to un­fold and pre­pare to be­gin ob­serv­ing some­time in 2019.

Un­like the Hub­ble, the Webb tele­scope is be­ing placed in or­bit around the sun, rather than the Earth. It will fol­low the Earth’s path, but nearly a mil­lion miles far­ther from the sun.

Project lead­ers said they are con­fi­dent that their cal­cu­la­tions and tests will en­sure a smooth jour­ney.

Given the long path the Webb tele­scope has taken al­ready, Bolden laughed when a re­porter asked if the fourth pres­i­den­tial ad­min­is­tra­tion to over­see the project — that of ei­ther Don­ald J. Trump or Hil­lary Clin­ton — could pose an un­ex­pected threat.

Though he lamented the de­par­ture of Sen. Bar­bara Mikul­ski, whom he called “a cham­pion” for the project through her role on the Se­nate’s Ap­pro­pri­a­tions Com­mit­tee, Bolden said he doesn’t ex­pect po­lit­i­cal forces to ground the tele­scope.

“We have an in­cred­i­bly good story to tell,” he said.

KIM HAIRSTON/BAL­TI­MORE SUN

The pri­mary mir­ror of the James Webb Space Tele­scope is 22 feet tall.

KIM HAIRSTON/BAL­TI­MORE SUN

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.