NASA James Webb Telescope: NIRSpec instrument installed into the heart

In this photo, engineers install the NIRSpec instrument in the heart (or ISIM) of NASA's James Webb Space Telescope (JWT). 

Credit: NASA/Chris Gunn

The last piece of the James Webb Space Telescope's heart was installed inside the world's largest clean room at NASA's Goddard Space Flight Center in Greenbelt, Md.


What looked like a massive black frame covered with wires and aluminum foil, the heart or Integrated Science Instrument Module (ISIM) now contains all four of Webb's science instruments.

Together, these instruments will help unlock the history of our universe, from the first luminous glows after the Big Bang, to the formation of stellar systems capable of supporting life on planets like Earth, to the evolution of our own solar system.

Teams of engineers recently navigated very cramped spaces with delicate materials and finished surgically implanting the last of the four instruments that will fly on the Webb telescope – the Near-Infrared Spectrograph (NIRSpec).

Weighing about as much as an upright piano (about 430 pounds, or 196 kilograms), the NIRSpec was suspended from a moveable counterweight called the Horizontal Integration Tool (HIT).


From below, the engineering team was tasked with painstakingly moving this vital instrument to its final position inside the large black composite frame, officially called the Integrated Science Instrument Module (ISIM).

As the team maneuvered this crucial instrument through very tight, hard to reach spaces inside the Webb telescope's heart, they ensured there was no unintentional contact with the frame because the instrument's materials are very stiff but brittle.

Disturbing any of those materials could have caused major setbacks that could damage NIRSpec.

"Part of the challenge is that this instrument cannot be installed in a straight linear move. In order to avoid interference with already installed systems, the instrument will have to follow a special pattern kind of like a dance," said Maurice te Plate, the European Space Agency's (ESA) Webb system integration and test manager at Goddard.

"During the crucial phases of the installation, the room is kept very silent because whenever there is a potential issue one of the engineers must hold the process until everything is checked out so they can proceed."

Engineers needed NIRSpec's six individual feet or legs to align with six designated "saddle" points on the ISIM within the width of a little more than that of a human hair.

To hit their marks, these engineers had rehearsed these complicated movements, performing simulations and precise calculations on both sides of the ocean.