NASA’s most costly telescope ever is in area ultimately. The $10 billion James Webb Space Telescope, an instrument anticipated to revolutionize astronomy by gathering gentle from the atmospheres of alien worlds and the universe’s first galaxies, launched at 7:20 a.m. Eastern Time on a sultry Christmas morning from Europe’s spaceport in French Guiana.
Some half-hour after launch, the telescope indifferent from the highest of its Ariane 5 rocket and deployed its photo voltaic array, which is required to cost its batteries and assist communication with Earth. Webb is now en path to its observing station, a gravitational stability level referred to as L2 at 1.5 million kilometers from Earth. Before it will get there, mission controllers may have a tense month, as they unfurl components of the telescope too giant to suit contained in the rocket fairing, together with its tennis court docket–measurement sunshield and 6.5-meter huge mirror. Until these are efficiently deployed and Webb’s 4 devices are chilled and examined, astronomers won’t relaxation straightforward.
As NASA’s first main area observatory in additional than a decade and the successor to the Hubble Space Telescope, loads is driving on Webb. The European Space Agency (ESA), a companion within the mission, and French rocket firm Arianespace might be blissful to have despatched the craft on its manner.
The closing prelaunch days weren’t with out incident. In mid-December, as Webb was lifted onto the payload adapter—its connection to the rocket—the sudden, unplanned launch of a clamp prompted a vibration all through the observatory. And after Webb was lifted to the highest of the rocket, engineers detected intermittent knowledge loss within the communication cable connecting Webb to the launcher. Resolving these points pushed the launch again to 24 December. Then unsettled climate intervened, delaying the launch yet another day—and leaving Webb competing with Santa’s sleigh for airspace. “Nothing is routine with Webb,” NASA science chief Thomas Zurbuchen stated at a briefing final week.
Webb’s formidable science objectives required quite a few technological firsts in its design, akin to a folding mirror made from 18 hexagonal gold-plated segments, and devices chilled to simply 7° above absolute zero (-266° C). That complexity led to schedule slips totaling 10 years and a value that ballooned from $2 billion to about 5 occasions as a lot.
It additionally led to a telescope that, to a level, should assemble itself in area—a course of fraught with dangers. Two hours after launch, a high-gain antenna is predicted to sprout from the craft to hurry communications; 12 hours in, Webb will make its first course correction burn, adopted by one other after 2.5 days.
So far, so easy. But on day 3, it’s the flip of the sunshield. The parasol, at present folded up towards the mirror, will drop right down to kind a platform under it. Two telescopic booms will stretch out and separate the sunshield’s 5 plastic layers, every no thicker than a human hair, making a thermal barrier that retains the shaded facet at -234°C—cool sufficient to keep away from interference with the infrared devices. That cooling takes time, nonetheless: The telescope and devices gained’t attain their working temperature till 3 weeks after arrival at L2. While that chill is sufficient for 3 of the sensors, the mid-infrared instrument have to be actively cooled to 7° above absolute zero, which takes an additional 6 weeks.
With the sunshield deployed, week two is when the telescope comes into play. First the tripod holding the secondary mirror in entrance of the principle mirror unfolds, then the 2 wings of the principle mirror, folded again for launch, swing into place. At a prelaunch briefing, ESA Director of Science Günther Hasinger stated it was like “a pupating butterfly unfurling its golden wings.” Once at L2 and absolutely cooled, operators should make sure that the 18 mirror segments kind a single reflecting floor. Using the near-infrared digicam as a sensor, they may measure any discrepancies. Tiny mechanical motors will regulate the phase positions and even their curvature till they’re completely aligned and formed to nanometer accuracy, a course of that takes a number of months.
Finally, with the mirror prepared, Webb will level at a choice of well-studied astronomical targets to check and calibrate the 4 devices. Then, roughly 6 months after launch, the practically 300 groups of astronomers who will use Webb in its first yr will lastly get to view the universe with area’s largest eye. As NASA Deputy Administrator Pam Melroy stated at a briefing this week: “We’ve done everything we can to make Webb a success. Now we just have to make it happen.”