Char­lie Sobeck AIR & SPACE IN­TER­VIEW

En­gi­neer, NASA Ames Re­search Cen­ter, Cal­i­for­nia

Air & Space Smithsonian - - Soundings -

Air & Space: What are the ad­van­tages of Ke­pler’s sim­ple de­sign?

What we’re ba­si­cally look­ing for is the shadow of plan­ets as they cir­cle their stars. As the plan­ets or­bit their host star, if the align­ment be­tween the star, planet, and tele­scope is cor­rect, we will see that planet tran­sit right in front of the star, and we can mea­sure a dim­ming in the bright­ness of the star. Con­cep­tu­ally, this is a very sim­ple prin­ci­ple to un­der­stand.

Are there any dis­ad­van­tages to such a stream­lined de­sign?

No one tele­scope is go­ing to do all things. For what Ke­pler was de­signed to do—find these plan­ets and char­ac­ter­ize them—we were able to do that job re­ally well with what we had. The next thing that we would like to do in un­der­stand­ing ex­o­plan­ets is to un­der­stand whether there are at­mos­pheres and if there are, what might be in those at­mos­pheres. To do that, you would need to be able to take a spec­trum: be able to sep­a­rate the light com­ing from a star into dif­fer­ent wave­lengths. Ke­pler does not have that abil­ity.

Ke­pler has ex­ceeded its orig­i­nal life­span of three and a half years. Do you know how much longer it will re­turn data?

The space­craft it­self is still ca­pa­ble of work­ing quite well, and what’s go­ing to limit its op­er­a­tion right now is fuel. We do burn fuel slowly, and we have a lim­ited amount, but we be­lieve that we have enough fuel to last an­other maybe three years.

It’s not op­er­at­ing for the Ke­pler Mis­sion be­cause it can no longer point at the Ke­pler field of view [an ap­prox­i­mate 100-square-de­gree sec­tion of sky be­tween the con­stel­la­tions Cygnus and Lyra]. We’ve lost two of our four re­ac­tion wheels [which point the space­craft and con­trol its at­ti­tude]. But we’ve been able to repur­pose the space­craft and the in­stru­ment and look at other parts of the sky. And we call that mis­sion “K2.”

How many Earth-size plan­ets has Ke­pler de­tected to date?

I’m guess­ing a few hun­dred Earth-size plan­ets. Not nec­es­sar­ily in the right or­bit to be Earth-like at all. Many of them are go­ing to be very close to their stars, so they’re go­ing to be very hot plan­ets. What we’re re­ally in­ter­ested in is in the Earth­size plan­ets in the hab­it­able zone around stars that are like our sun. And we’re only now start­ing to un­cover that within the data. So we don’t have any con­firmed plan­ets in that cat­e­gory. We do have now six can­di­dates, and we have to fol­low up on those to con­firm if they are real plan­ets. That would be the ul­ti­mate prize: to find that kind of a planet—one that re­sem­bles the Earth.

SOBECK IS PRO­JECT MAN­AGER for the Ke­pler Mis­sion. Launched in 2009, the Ke­pler space ob­ser­va­tory, now in a he­lio­cen­tric or­bit, was de­signed to look for Earth-size plan­ets around other stars. The Ke­pler team re­ceived this year’s Na­tional Air and Space Mu­seum Tro­phy for Cur­rent Achieve­ment.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.