“Give me a telescope, and I can give you one thing good to do with it,” says Jane Rigby, an astrophysicist at NASA’s Goddard House Flight Heart who serves because the company’s operations venture scientist for the $10-billion James Webb House Telescope, the biggest and strongest off-world observatory but constructed by humankind. Over the course of her profession, Rigby has used most of the world’s premier ground- and space-based astronomical services—and she or he is helming one in every of Webb’s many “early launch science” campaigns front-loaded for its first yr of observations, using the telescope to check star formation in galaxies throughout eons of cosmic time. However her predominant work with Webb is to work along with her workforce to make sure everybody lucky sufficient to make use of it could do “one thing good,” by taking care of the total breadth of scientific investigations the telescope will carry out for researchers across the globe throughout its deliberate five-year major mission. That is no small job: For these hoping to squeeze as a lot science as potential out of this one-of-a-kind observatory, each second of Webb’s time is treasured—and Rigby oversees the schedule.

Ever since Webb launched on Christmas Day of 2021, she and her colleagues have been working nonstop to arrange the observatory to ship breakthrough discoveries concerning the universe’s first galaxies, close by exoplanets and rather more. Now, with its mirrors and devices prepared and its inaugural batch of science photographs and knowledge set for imminent launch, Webb’s revolutionary research are poised to actually start. Scientific American spoke with Rigby concerning the teamwork it takes to function Webb, the observatory’s unsure longevity and the fragile job of maximizing returns on a $10-billion funding within the greatest and finest telescope within the identified universe.

[An edited transcript of the interview follows.]

Issues are trying good for Webb, aren’t they? We’re on the verge of seeing the telescope’s first science photographs, its efficiency has exceeded expectations throughout commissioning, and its voyage to deep area left it with sufficient surplus propellant to proceed operations into the 2040s—a few years past its “nominal” mission lifetime. How exceptional to suppose we’d get a lot “further” day trip of this factor that’s required many years of regular, diligent work and $10 billion, this superb facility which will in some respects be the only greatest funding ever made in astrophysics. So I wished to speak to you about how the venture is defending this funding, and the way it’s going to maximise the juice for the squeeze, so to talk.

Issues are trying nice, completely. This telescope actually just isn’t solely pretty much as good as we promised—in some ways, it’s higher. And I’m comfortable to speak about all elements of juice-making. Like everybody else on the workforce I’m excited to unveil Webb’s first science photographs. This would be the first time we truly put some “juice” out, and from there everybody can choose for themselves how candy it’s. I like this “juice” metaphor—as long as we’re not speaking about steroids.

Wait, however isn’t Webb “Hubble on steroids”? Sorry, dangerous joke.

It could take plenty of steroids, truly. Webb is 100 occasions extra highly effective than current observatories.

Ha, okay. So that you’re Webb’s venture scientist for operations. Does that imply you’re making all of the juice?

Nicely, one of many issues a venture scientist does is act because the conscience for the science. This telescope was principally constructed by engineers and managers, however scientists needed to be within the loop, too, to make sure that it could do the science for which it’s being constructed. Now, as an “operations” venture scientist, which means I fear about how we’re going to make use of the telescope—the whole lot from deciding on proposed observations to creating observing schedules, from working the telescope to getting the information again to Earth and eradicating all of the instrumental signatures. No matter it takes to get the science finished.

Proper. So, simply to be clear, you’re operations venture scientist, however that doesn’t imply you select the place Webb appears to be like or who will get to make use of it.

There’s no “who you realize” inside monitor. Most of Webb’s time is allotted via very aggressive peer overview. For Cycle 1 Normal Observer applications, we enlisted a panel of 200 specialists—all digital due to COVID—to overview and rank greater than a thousand proposals from everywhere in the world. The highest quarter of proposals have been chosen. That’s finished twin anonymously: reviewers don’t know who wrote the proposals, and the proposers don’t know who critiques them. We wish to choose by the standard of the concepts. Which means, as an example, it’s potential for an autodidact from outdoors academia to get time on Webb. You can reside in a rustic that doesn’t essentially like our nation, or that didn’t do something to assist construct the telescope, and normally you may nonetheless use it, proper? It’s an open competitors as a result of we would like the perfect concepts.

How do you juggle all of those “finest” concepts, although, to determine which of them take precedence? Looks like a tough job.

This can be like explaining the distinction between constructing a juicer versus truly utilizing it to make juice, seeing the place it will get jammed up, and fixing it.

So, first some fundamentals: Webb can level anyplace inside a 3rd of the sky on any given day. That restriction makes positive that the sunshield is all the time oriented in order that it blocks gentle from the Earth, the Solar and the moon. That area of observability precesses such that Webb can see 100 % of the sky over the course of a yr. Realizing that, for any mounted goal (as in a single not whizzing across the photo voltaic system), we are able to calculate which and what number of days per yr Webb can see it. Targets within the aircraft of our photo voltaic system can be found for about 60 days a yr. Targets out of the aircraft (straight as much as the north or south poles of our photo voltaic system) can be found year-round. Targets in intermediate ecliptic latitudes fall between these extremes.

Some targets we have to observe at sure occasions. Like exoplanets at sure factors in orbit round their stars, or an exploding star, or another phenomenon that’s time-dependent.

There’s additionally a query of how darkish the sky is. For some targets and wavelengths, it issues quite a bit whether or not you’re trying via sizzling mud towards the Solar or colder mud additional out within the photo voltaic system. So for a given goal, how darkish the sky is for observing it varies seasonally. For some observations, we don’t actually care. But when we’re actually faint issues, then we wish to schedule when the background sky is as darkish as potential.

We additionally don’t need Webb to be idle. And, we have to get the information again to Earth. We speak to Earth a few third of the time throughout regular science operations, with a gimbaled antenna we are able to level whereas we’re observing. The info charge isn’t dangerous—about 30 megabits per second—nevertheless it’s slower than a cable modem, and there are 57 megapixels of reminiscence inside Webb’s devices. We handle that by asking customers to not be knowledge hogs, and by doing plenty of knowledge compression.

We schedule the telescope by optimizing over all these constraints, to generate a household of acceptable options. We make a long-range plan, during which for each commentary, we assign perhaps a month-long time slot the place it’s prone to go. After which each seven to 10 days we’ll make an in depth schedule for that week—the batting order, so to talk. This course of is tailored from Hubble, which additionally has numerous constraints, although Webb’s are fairly totally different than Hubble’s.


First off, for Hubble the Earth is in the best way half the time. Hubble makes use of that point to slew to the following goal, and in any other case prepare. Webb doesn’t have that challenge, because it’s in deep area. Which means Webb can’t conceal its slews behind the Earth like Hubble does. Webb is an enormous telescope, so it slews slower than the minute hand on a clock. So if you wish to flip it 180 levels, that takes most of an hour. So to make use of gendered language, scheduling is the traditional “touring salesman” downside—how do you optimize a bunch of various “stops” to kind a route? We hyperlink up a bunch of visits which might be shut collectively within the sky to keep away from doing large, time-consuming slews.

There’s one other means Webb and Hubble are totally different which is necessary for scheduling and caring for the telescope, and that’s momentum buildup. It seems that the truth that photons carry momentum units a restrict on the lifetime of the telescope. As a result of propellant is among the predominant constraints on Webb’s lifetime, and momentum administration is one in every of Webb’s predominant makes use of of propellant.

May you unpack that for us a bit?

Photons hanging Webb’s sunshield apply torque. Now, we may orient the sunshield to cancel out the torques—however we wish to level the telescope at targets, not get the sunshield completely balanced by daylight. So the photons hit the sunshield, they apply torque, and Webb’s response wheels spin as much as counteract this impact and hold the telescope pointed. However the response wheels can solely spin so quick. They sometimes need to dump their angular momentum. In low-Earth orbit, Hubble simply {couples} the response wheels to the Earth’s magnetic area to gradual them down. That doesn’t work out in deep area, so as a substitute Webb fires thrusters to push towards the spin of the response wheels. We do these momentum dumps periodically, every time utilizing little propellant. However, as you talked about, at this stage we now have sufficient propellant to get into the 2040s, so Webb’s longevity is extra prone to be restricted by how lengthy elements final…. Actually, although, it feels bizarre to be plotting the nursing-home days of this telescope when it’s nonetheless a new child simply opening its eyes!

You may not like this subsequent query, then: Assuming the whole lot else stays peachy, and propellant inevitably runs out, how will Webb die?

Wow, so we actually are speaking concerning the dying of this factor. I virtually don’t wish to speak about this; it feels untimely, as a result of it’s a brand-new telescope. It’s like speaking concerning the dying of a child. If we’re speaking about being propellant-limited, as soon as that useful resource runs out, we’d be unable to manage the pointing to make sure the photo voltaic panels all the time see the Solar and the telescope by no means sees it. Ultimately the photo voltaic panels would fall into shadow for lengthy sufficient that restoration could be unlikely. I suppose that might be like Webb’s final breath. That may be once we’d comprehend it was actually useless. However, once more, it’s onerous to know what precisely will occur to Webb in its twilight years because it’s a new child.

We’ve already been shocked, as an example, by a micrometeorite affect that had a better than anticipated impact on one of many major mirror segments, and we’re actively finding out what such occasions may imply for Webb’s ongoing optical efficiency. Micrometeorites are a reality of life in orbit that may step by step degrade the standard of the mirrors and the sunshield—and we’ve overengineered and inbuilt margins with that in thoughts—however was this a once-every-five-years occasion, and we simply bought unfortunate, or are we going to be getting extra hits like this than we anticipated? We’re working to determine that out. I’m nonetheless planning for a protracted, fruitful mission, in fact.

Certainly. You already know, it does seem to be you and folks who work on Webb have, fairly fairly, shaped an emotional attachment to it. Has that made it more difficult to navigate all the assorted make-or-break moments within the telescope’s so-far-short life?

Nicely, the emotions change for every distinct section of Webb’s commissioning. Through the launch and within the first couple of weeks afterward once we have been doing main deployments, there have been a number of key days the place we knew we’d lose the mission that day. We have been up entrance about that; NASA even made this video referred to as “29 Days on the Edge.” I attempted to strategy these days with fatalism: “If it doesn’t work, we don’t have a mission.” As one deployment after one other labored, I noticed I used to be going via the phases of grief. Principally bargaining: “Oh, let’s please simply get the secondary mirror out, I don’t even want the first mirror to unfold its two wings!”

Why the secondary mirror?

The phrase “secondary” makes it sound prefer it’s not that necessary, or a backup. However in a telescope, secondary simply means the sunshine hits it second, after the first. Webb’s major mirror is iconic and far bigger. However that 0.7-meter secondary is totally essential. If the secondary mirror deployment hadn’t labored, then the sunshine bouncing off that beautiful major mirror would fly out to area, misplaced ceaselessly, as a substitute of being collected in a science instrument. Even when the first mirror hadn’t absolutely unfolded, if we nonetheless had that secondary mirror, we’d have a functioning however degraded telescope. So when the secondary mirror deployed, completely, I noticed how a lot fear I had been holding onto, after engaged on this factor for the previous 11 years—and plenty of my colleagues have labored on it longer.

We’re fortunately finished with these make-or-break moments, in addition to the “commissioning” section of intense choreography and testing. The telescope has cooled to its goal temperature, the optics are aligned, the science devices are prepared. We’ve been attending to know the precise telescope’s true efficiency in area, and with the primary science photographs we’ll present not solely that Webb is working, however that it’s absolutely able to doing all of the superb science for which it was constructed. It’s a beautiful feeling.

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