When NASA announced that the new Nancy Grace Roman Space Telescope will perform its science duties from a point in space known as Lagrange 2, many observers noted that the space agency’s current state-of-the-art space observatory, the James Webb Space Telescope, shares this same orbital location.
Due to the extremely sensitive nature of both satellites and their sensors, and the irreplaceable scientific value they will provide in the future, it might seem natural to wonder whether these two space observatories are at risk of a deep-space collision.
Fortunately, that’s a very unlikely prospect, and here’s a look at all the space separating Roman and Webb—and how NASA will ensure the two observatories remain safely apart.
Nancy Grace Roman Space Telescope Heading for Lagrange 2
Many scientific satellites reside a little over 200 miles above Earth in an orbital plane called Low Earth Orbit (LEO). This proximity enables communication with Earth and offers the potential for future servicing missions.
For example, NASA’s groundbreaking Hubble Space Telescope orbits LEO at about 300 miles above Earth. This proximity enabled servicing missions that have kept Hubble delivering valuable scientific data for over three and a half decades since its 1990 launch. Still, LEO also limits which missions Hubble can undertake.
More recently, NASA launched JWST. However, unlike Hubble, Webb rocketed roughly one million miles from Earth before arriving at Lagrange 2. According to a NASA fact sheet detailing the Roman Space Telescope’s mission, this location offers several benefits over LEO.
“At L2, the gravity of the Sun and Earth, together with an object’s motion around the Sun, let it stay lined up with Earth as they orbit,” NASA explains, “allowing Roman to have a relatively steady orbit without using much fuel.”
NASA also notes that heat from Earth, the Sun, and the Moon has less impact on infrared telescopes designed to “see” heat. L2 also offers JWST and Roman, “a constant, unobstructed view of a wide swath of the sky.”
“Earth won’t block much of Roman’s view since it will be so distant,” NASA explains.
Is There a Danger of a Roman-JWST Collision?
Instead of sitting still at the heart of L2, NASA notes that Webb “traces out a large orbit around the actual L2 point.” For comparison, the space agency noted that JWST’s orbit around L2 is “much larger than the Moon’s orbit around Earth.”
Like Webb, the Nancy Grace Roman Space Telescope is also destined for L2. The new space telescope will also trace out an orbit around L2 rather than remaining comparatively stationary.
Because of the wide orbits of both spacecraft and the efforts of the mission’s controllers, NASA said the two valuable space telescopes “will easily be kept far apart.”
Five-Year Mission Could Stretch to Ten or Beyond with Refueling
Like previous NASA missions, Roman will have a primary lifetime and a backup plan if the observatory remains viable after the first mission ends. For Roman, both the primary and secondary missions are slated for five years, bringing the observatory’s planned potential lifetime up to a possible ten years.
Notably, several NASA missions have continued to deliver scientific data well beyond their planned primary and secondary missions. Perhaps the most famous example is Voyager 1. Launched in 1977, the interplanetary mission has since left the solar system and continues to return data from beyond the heliopause, an area of deep space over 14 billion miles from Earth.
When discussing what obstacles may result in a shorter mission profile, NASA said that “fuel is expected to be the mission’s life-limiting resource.”
“While NASA does not currently have an ability to service observatories at L2, Roman is designed to be refuellable,” they added.
Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org.