[MUSIC PLAYING] It's been more than a decade since the Hubble Space Telescope gave us this iconic image of a small slice of the universe. With a seemingly countless number of galaxies and other celestial objects to study, one of Webb's instruments, NIRSpec, or Near-Inrared Spectrograph, is uniquely designed to overcome this challenge. Joining us now is the James Webb Space Telescope project scientist for the European Space Agency, and he's here in Greenbelt, Maryland at the NASA Goddard Space Flight Center. Thanks for joining us. First of all, what exactly is a spectrograph? 

A spectrograph can take light of one of its objects and divide it in its colors. An astronomer can study how much light is present in each color. This is what we call a spectrum, and this is why NIRSpec is called a spectrograph. 

So, what do colors tell us? 

The colors tell us a lot of things about the object. It can tell us what it is made of, how it moves, how far it is from us, all this type of information. 

So, what makes NIRSpec so special? I'm sure there are other spectrographs up in space. 

NIRSpec was the first multi-object spectrograph in space. It's able to obtain spectra of multiple objects at the same time. 

How far along are you in building NIRSpec? 

We are assembling it, and this is done in Germany at Astrium, our main contractor, and in fact, it would be a very good time to go there to see it before we put the protective cover on it. 

Well, thanks a lot for your time and telling us a little bit about the science of NIRSpec. 

Thanks a lot. 

Hi, Ralf. 

Hi, Mary. 

Pierre just gave us a rundown about the science of NIRSpec, and I was hoping you could tell me more about NIRSpec, the instrument. 

Yes, for sure. The NIRSpec development is, for the Astrium team, really fascinating stuff because we have the unique opportunity to apply new technologies in space. 

Is that instrument back there NIRSpec? 

This is the first model for NIRSpec, which we have developed to learn all about the feasibility of this technology, but it's not yet the flight model. The flight model is over here, and we can have a look on it. 

Sounds good. 

Mary, now here, you see the flight instrument. The cover is not yet on. You can do a slight flight through the instrument starting from the light, which comes from an intermediate focus from the telescope. 

OK. 

Goes up there in a periscope, like the submarines. 

Yeah, that's what it reminds me of. Yeah. 

Then we are on the other side of the plate, and then we have another telescope. And this telescope prepares the image for the entrance of the spectrograph. Spectrograph is the area where the light is split up in its colors. We should move around and see it from the other side. 

So, now we are on the spectrographic part of the instrument. The light is spread up in these colors. These beams are then focused on the detector with another telescope, which is another three mirrors. And then we have the colors on the detectors and can evaluate them further downstream electronically. 

Well, thank you so much for showing us or giving us a guided tour of NIRSpec. 

You're welcome. 

As you can see, NIRSpec gives astronomers a powerful tool, a tool that will let astronomers study as many as 100 objects at the same time. Thanks for joining us for this edition of Behind the Webb. 

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