Free Astronomy Magazine March-April 2024

MARCH-APRIL 2024 mission to a fast-mov- ing target — perhaps even a visiting inter- stellar object, suggests Eggl. “Rubin is capable of giving us the prep time we need to launch a mission to in- tercept an interstellar object. That’s a synergy that’s very unique to Rubin, and unique to the time we’re living in.” In fact, such mis- sions are already in de- velopment — the JAXA/ESA Comet Inter- ceptor mission will launch in 2029 and await the discovery (likely by Rubin) of a visitable long-period Solar System comet or interstellar object passing by the Sun for the first time. Rubin’s detailed and frequent ob- servations of Solar System objects and their locations could benefit space missions already in progress as well, alerting scientists to worth- while observing opportunities near a spacecraft’s path, or within reach via a small detour. NASA’s Lucy, for example, is on a 12-year mission that Rubin is well-poised to influ- ence. Lucy, the first space mission sent to study asteroids trapped in and around Jupiter’s orbit, has al- ready returned valuable scientific information — and some unex- pected results. And, when Rubin’s survey begins, smaller, fainter aster- oids near Lucy’s future path will come into view for scientists here on Earth for the first time, potentially offering new flyby opportunities — and new scientific surprises — we can’t begin to predict. “With our current telescopes we’ve essentially been looking at the big boulders on the beach , − says Eggl, − but Rubin will zoom in on the finer grains of sand.” I n this illustration, a mosaic of several of Rubin Ob- servatory’s observation footprints is projected upon some of the millions of asteroids that scientists will find in Rubin’s vast Legacy Survey of Space and Time (LSST) dataset. A few of these asteroids may prove scientifically interesting enough to launch or redirect a spacecraft to investigate them. [RubinObs/NOIR- Lab/NSF/AURA/J. Pinto] tory is a Program of NSF’s NOIRLab, which, along with SLAC National Accelerator Laboratory, will cooper- atively operate Rubin. The Solar System, our cosmic back- yard, is teeming with billions of small rocky and icy objects. Most formed in early times, such as near- Earth objects and Trojan asteroids, while others are distant travelers from solar systems beyond our own, known as interstellar objects. Over the ten-year Legacy Survey of Space and Time (LSST), Rubin Obser- vatory will scan the entire southern hemisphere sky every few nights with an 8.4-meter, fast-moving tele- scope and the largest digital camera in the world, revealing millions of previously unknown Solar System objects for the very first time. Rubin Observatory’s survey is expected to potentially quintuple our current census of known objects in the Solar System, which scientists have been painstakingly building for more than 200 years. “Nothing will come close to the depth of Rubin’s survey and the level of characterization we will get for Solar System objects,” says Siegfried Eggl, Assistant Profes- sor at University of Illinois Urbana- Champaign and Lead of the Inner Solar System Working Group within the Rubin/LSST Solar System Science Collaboration. “It is fascinating that we have the capability to visit inter- esting objects and look at them close-up. But to do that we need to know they exist, and we need to know where they are. This is what Rubin will tell us.” While detecting millions of new in- dividual objects, Rubin will also pro- vide information about the Solar System’s broader landscape and re- veal whole regions that contain sci- entifically interesting or unique objects to consider for future space missions. “If you think of Rubin as looking at a beach, you see millions and mil- lions of individual sand grains, that together constitute the entire beach,” says Eggl, “There might be an area of yellow sand, or volcanic black sand, and a space mission to an object in that region could inves- tigate what makes it different. Often we don’t know what’s weird or interesting unless we know the context it’s in.” In addition to providing as- tronomers and astrophysicists with the most comprehensive, big-picture view of the southern sky to date, Rubin will also alert them to changes in the night sky within 60 seconds of detecting them. This early warning system could prompt scientists to start preparing a space ! ASTRO PUBLISHING