On July 30, the India-US house collaboration crossed a historic milestone with the profitable launch of NISAR, or the NASA-ISRO Synthetic Aperture Radar satellite, a flagship earth commentary mission collectively developed by the 2 nations’ house programmes. It is the primary satellite to make use of radars of two frequencies — the L-band radar by NASA and the S-band radar by ISRO — to repeatedly monitor the earth’s floor. NISAR is anticipated to offer unprecedented information on land deformation, ice-sheet dynamics, forest biomass, and pure disasters like earthquakes and floods. With its high-resolution, all-weather, day-night imaging capabilities, NISAR goals to boost local weather resilience, agricultural monitoring, and catastrophe response. Beyond science, NISAR additionally holds business promise to allow new information providers, geospatial analytics, and early-warning programs throughout sectors equivalent to insurance coverage, infrastructure, and agriculture.
To focus on this scientific milestone and what this implies for house cooperation, Vasudevan Mukunth and Kunal Shankar spoke to Karen St. Germain. Dr. St. Germain is the director of the Earth Science Division on the Science Mission Directorate at NASA, the place she oversees NASA’s full earth science portfolio, together with satellite missions, know-how, utilized analysis, and data-to‑motion packages.
Vasudevan Mukunth: Karen, thanks a lot for becoming a member of us at present. Can you give us a number of examples of scientific research that are doable with NISAR, however haven’t been doable to date with the prevailing crop of Earth commentary satellites?
Karen St. Germain: Absolutely, and it’s nice to be with you. The means to consider NISAR is that it will see something that has construction to it that strikes, that adjustments its place at a scale of lower than a centimeter over an space about half of a tennis courtroom. When I say something that has construction: it may very well be forest, it may very well be buildings, it may very well be glaciers, mountains, land. Anything that strikes, we’ll see at an unprecedented degree of constancy.
What that means is we will be capable of see the slight bulging that occurs earlier than a volcano erupts. We’ll be capable of see the land turning into unstable earlier than a landslide. We’ll be capable of see constructing shifts after an earthquake or another kind of occasion. When a forest will get reduce down, we’ll be capable of see that. Anything that adjustments, we’ll be capable of see, and that’s a rare new functionality for us.
Kunal Shankar: After the launch, NISAR will begin its 90-day commissioning section. And that is the world’s first twin band SAR satellite. In this section, do you foresee any challenges with calibration, particularly with cross-band calibration? Could you break down that course of for us?
Karen St. Germain: There are numerous totally different elements to the calibration. Largely the ISRO workforce will concentrate on calibrating the S-band radar and the NASA workforce will concentrate on calibrating the L-band radar. They don’t actually get cross-calibrated, however every one will have a look at its personal particular targets.
Now, what do I imply by a goal? It’s one thing we name a nook reflector and it’s precisely what it appears like. It’s a nook, identical to the nook of a room. And it has a particular characteristic, which is that when a pulse of vitality hits it from any course, it displays again in precisely the identical course. So we use these targets to calibrate independently every of the devices. And then the one different factor we actually need to pay particular consideration to is the alignment, the pointing. Are they pointing in the identical place on the bottom? And for that, we’ll use the info itself. So the info itself will establish options and we’ll align these options from every radar.
The GSLV-F16 mission lifts off carrying the NASA-ISRO NISAR satellite ISRO’s Sriharikota spaceport on July 30, 2025.
| Photo Credit:
ISRO/ANI
Vasudevan Mukunth: So NASA’s funding in NISAR is about $1.2 billion, proper?
Karen St. Germain: That’s about proper.
Vasudevan Mukunth: If doable, might you inform us how this price breaks down on the US aspect?
Karen St. Germain: The means NASA builds missions, we set up a life cycle price. So that life cycle begins after we begin designing and it runs via the design section, the construct, the combination, the launch, and throughout — what we name the prime mission, which for NISAR is the primary three years. For NISAR, that included the deployable antenna, which is essentially the most distinguishing characteristic of NISAR, and the L-band radar. And after all, the L-band and the S-band are working via the identical reflector. Then after all, there are numerous electronics and information dealing with parts as effectively.
And then there are the folks, proper? The folks that put all of it collectively and labored so intently with the workforce from India. So even after we had been completed constructing our half, our workforce got here to India to work with ISRO to combine it onto the spacecraft and put together for launch and even sat on the console for the launch. So it’s a complete price.
Kunal Shankar: Speaking of prices, there’s lots of curiosity concerning the business facet and the purposes facet of NISAR. Could you simply inform us a bit concerning the form of curiosity that it has generated?
Karen St. Germain: Actually, let me take a step again and discuss earth commentary information typically as a result of understanding the earth — the floor, the ambiance, and the adjustments giant and small that can have impacts on communities and companies, that’s grow to be an infinite space of curiosity. In reality, NASA’s been accumulating information on the earth system for greater than 60 years now. And we discover that about three quarters of our Fortune 100 firms are drawing one thing out of that earth commentary archive. We additionally discover that about 75% of our customers, and now we have greater than 5 million customers, are coming from .com addresses. So we’re speaking about agriculture producers, the insurance coverage business, the finance business, the transportation business. And that’s earlier than you even get to issues like catastrophe response. So now we have an amazing curiosity typically.
For NISAR particularly, we all know that NISAR will produce information that can immediately profit agriculture, additionally threat evaluation — every thing from pure hazards like earthquakes and volcanoes, that are each points within the US but in addition issues like wildfire threat as a result of NISAR will be capable of characterise how a lot gas is in our wildlands. So that’s dry gas that is burnable. There are all these software areas. One of the issues that we do that we’re actually enthusiastic about is any time we launch a brand new mission, now we have an Early Adopters program. These are folks on the market who anticipate what NISAR may do for them of their enterprise. We don’t require that they inform us loads about what they intend to do. But proper now for NISAR, now we have no less than 200 of those Early Adopters. Once the info begin to roll out and the thrill builds, we anticipate it to take off from there.
Kunal Shankar: Which you consider is a excessive quantity.
Karen St. Germain: The Early Adopters, yeah. It’s a excessive quantity for a mission that is as refined as NISAR. What I imply by that is: footage are usually straightforward for folks to make use of. Synthetic aperture radar information requires some fairly advanced processing to show it into usable info. But all the info is free and overtly out there from us. We will distribute the L-band information out of the Alaska SAR facility and our colleagues at ISRO will have their very own distribution mechanism for the S-band information, and it will even be open and freely out there.
Vasudevan Mukunth: Two-hundred is a giant quantity. Also, are you able to clarify why NISAR took 11 years to construct? Were there any notably tough engineering challenges that you needed to overcome first?
Karen St. Germain: Yeah, completely. First, it’s an enormously advanced system, with many dozens of subassemblies that needed to be designed. Of course, to make these two radars work collectively and function via a single reflector, there’s lots of design work that needed to occur up entrance. So it was difficult to start with. And then we had a few different specific challenges. This one occurred proper as I used to be beginning my job: COVID hit. So take into consideration an built-in engineering workforce already separated by time zones and distance and now having to work via a world pandemic. A whole lot of this work additionally needed to occur in individual. We had individuals who needed to journey on the top of COVID, and needed to go away their households. Remember that the waves of COVID hit otherwise within the US and India. We had folks on each groups generally come down with COVID once they had been within the reverse nation, so we needed to handle each other’s groups. Then we needed to develop solely new protocols for the way folks might work collectively in an area and stay wholesome. That was a giant one.
More not too long ago, this reflector is gigantic, it’s a few 40-foot deployable reflector. And after we had been in India integrating and we had been testing within the thermal vacuum, we noticed some information that nervous us. We had been actually afraid that there could also be an excessive amount of of a thermal load on that reflector earlier than it will get deployed, and it’d overheat. If it did that, it might problem the structural integrity. Of course, while you’ve obtained a deployable antenna, if it doesn’t keep taut, it doesn’t mirror the best way you need it to. So we ended up de-mating that reflector, bringing it again dwelling, making use of a reflective coating so the solar couldn’t trigger it to overheat, on the struts (not on the reflector floor itself). Then we needed to ship it again and reintegrate. So we had a few technical challenges, which we anticipate while you’re doing one thing as tough as this.
An artist’s illustration of NISAR orbiting the earth. The 12-m-wide reflector is seen deployed.
| Photo Credit:
NASA
Kunal Shankar: Speaking of challenges, what do you suppose are the constraints when it comes to penetration depth of the L-band versus the S-band?
Karen St. Germain: I’d not body it a lot when it comes to limitations as I’d body it that they’re each specialists and so they simply have totally different specialties. So the L-band has an extended wavelength and that means it might probably penetrate deeper. It can penetrate via foliage. Of course they’ll each be capable of create imagery in day and evening via clouds and climate. It’s simply that when there may be some materials there like foliage, the L-band will penetrate additional: it will work together with bigger buildings. The S-band will provide you with extra details about that foliage as a result of it’s extra delicate to it. That’s only one instance. They will actually simply see various things. And their energy then will be after we mix the knowledge from them and get a extra holistic holistic view, proper?
Vasudevan Mukunth: This is form of a observe as much as that. Both the L-band and the S-band radars use the identical reflector. Since S-band has a shorter wavelength than the L-band, does this create any trade-offs in both L-band or S-band efficiency?
Karen St. Germain: It doesn’t. And the rationale for that is as a result of it is a artificial aperture radar. It creates its spatial decision because it strikes alongside. Each radar is taking snapshots because it strikes alongside. You know, to get this type of centimetre degree constancy and the form of spatial decision we’re attaining, in the event you had been to make use of a strong antenna, it must be 5 miles lengthy. Just like while you’re speaking a few digital camera, if you would like to have the ability to get excessive constancy, you want a giant lens. Same concept. But we are able to’t deploy an antenna that massive. So what we do is we construct up picture after picture after picture to get that decision. And due to this system, it’s really impartial of wavelength. It works the identical for S- and for L-bands. The solely factor that’s just a little totally different is as a result of the antenna feeds for the L-band and the S-band can’t bodily occupy the identical house, they need to be subsequent to one another and that means there’s a slight distinction in the best way their pulses mirror off the antenna. There’s that positioning distinction, and that we are able to appropriate for.
Vasudevan Mukunth: Could you inform us just a little bit extra about that slight distinction?
Karen St. Germain: It’s the best way a reflector works. You would ideally need to put the feed at the point of interest of the reflector. But when you’ve two feeds, you’ll be able to’t do that. So they’re barely offset. That means they illuminate the reflector simply barely otherwise. The alignment is just a bit bit totally different. The workforce optimised the design to minimise that distinction and to make it so that they might appropriate it in post-processing.
Kunal Shankar: How do NASA and JPL’s radar programs for planetary exploration feed into and evolve from their Earth commentary programs? And even on the moon, NASA and ISRO have been collaborating particularly utilizing radar programs on the DFSAR on Chandrayaan-2 orbiter and the Mini-RF on LRO. Can we think about a NISAR constructed for missions to the moon, Mars or past?
Karen St. Germain: Of course, upon getting experience in a know-how, you should use it in lots of, some ways. And that is usually the case in NASA between earth science and planetary science. One of us will develop a brand new know-how or advance a brand new know-how after which it may be used very broadly. So completely! And we love that form of interaction. I really like seeing earth science applied sciences make it into planetary missions.
That’s one facet. The different factor is what we study from NISAR on earth can inform what we perceive about different planets. There are plenty of methods that we work together throughout disciplines.
Vasudevan Mukunth: Could you give us an instance of a lesson that you’ll study from NISAR that would assist with the planetary mission?
Karen St. Germain: Let’s see. One of the issues that NISAR goes to inform us about is what’s occurring beneath the crust of the floor as a result of we’ll be capable of see these very small motions that you and I don’t expertise day by day, proper? We can’t sense these. But NISAR will, and it will enable us to advance our fashions about how the inside of planets work. And these sorts of fashions are the identical fashions we use after we attempt to perceive how a planet like Mars works.
Vasudevan Mukunth: NISAR is a primary of its type equal partnership between NASA and ISRO. Can you inform us what sort of precedent this collaboration units for future main collaborations or know-how sharing between the 2 organisations?
Karen St. Germain: First, I will say I’ve been singularly centered on getting NISAR off the bottom and not likely wanting past. Of course, you already know, once I was making ready for launch, I went and acquired just a little determine of Ganesh. Because my understanding is that Ganesh brings good tidings for the start of an enterprise.
And for so long as we’ve been engaged on NISAR, the launch actually represents the start of that collaboration. We will be working collectively intently for a few years simply to extract all the worth out of NISAR. But as you mentioned, NASA and ISRO are working collectively in some ways in human exploration and probably in different areas. I hope, and I believe that, we will have a wealthy collaboration for a really very long time and I believe it will span the areas of curiosity from earth science to planetary science and human exploration.
