The agency cleared the eight missions to run for another three years, except for the asteroid-hunting spacecraft OSIRIS-REx. That mission will run for at least another nine years as it chases down the near-Earth asteroid Apophis, once thought to be the most hazardous asteroid in the Solar System.
Some of the extensions simply continue the goals of current missions, while others, like OSIRIS-REx and New Horizons, are getting new directives as they move beyond their primary missions.
Mission extensions are a fairly routine part of the life of a NASA spacecraft. NASA launches all missions with a primary goal, like taking new images of Pluto. Many, though, survive long beyond that first mission and have enough fuel and working instrumentation to keep giving us valuable data. The most inspiring example may be the two Voyager spacecraft, which send back data more than 40 years after launch and after entering interstellar space.
That kind of longevity is rare, but many older NASA missions are still kicking. The most recent crop of mission extensions includes five on Mars alone, on spacecraft both on and above the planet.
The Mars Atmosphere and Volatile Evolution (MAVEN) orbital mission will be watching how Mars’ atmosphere and magnetic field change during an upcoming solar maximum, when the Sun’s activity increases. The Mars Odyssey spacecraft, a 21-year-old orbiter mission to the Red Planet, will search for evidence of subsurface rocks and ice, monitor radiation levels and climate, and act as an important relay for communications from other spacecraft on Mars back to Earth. The Mars Reconnaissance Orbiter (MRO), now in its sixth extended mission, will also be relaying communications, as well as studying the planet’s surface, ice, active geology, and more.
Down on the surface, the Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) lander will continue to monitor seismic activity on Mars — including so-called “Marsquakes” — and weather. But with its solar panels covered in dust, the mission might not survive for long, and its only hope might be for a passing dust devil to scour it clean. Also pushing valiantly forward on Mars is the Curiosity rover, which has already ventured more than 16 miles across Gale Crater in its nearly 10 years on the Red Planet. Curiosity is set to climb to higher elevations in the crater in its fourth extended mission and further explore the history of water on Mars.
Closer to home, NASA also extended the Lunar Reconnaissance Orbiter (LRO) mission to continue studying the surface and geology of the Moon and search for water ice in permanently shadowed regions of our satellite as its orbit takes it away from the poles. These regions are essential for future human missions to the Moon, like the Artemis program.
Another asteroid for OSIRIS-REx
NASA’s flagship asteroid-hunting spacecraft OSIRIS-REx also got a mission extension, and with it, a brand new target. The spacecraft is currently returning to Earth to deliver a sample of the asteroid Bennu, which it intercepted back in 2018. Once it swings by Earth in 2023 to drop off its payload, the spacecraft will be heading back out to meet 99942 Apophis, an asteroid set to zoom close by Earth in 2029.
Apophis measures about 1,200 feet in diameter. It will come within about 20,000 miles of our planet, or about one-tenth of the distance to the Moon. That’s close enough that Apophis will be visible with the naked eye for a short time. While our planet’s in no danger, the flyby represents the perfect opportunity to learn more about the asteroids that come very near Earth.
“We have the capability to get up close and personal with a small asteroid, which is really pretty challenging because these are microgravity objects,” Daniella DellaGiustina, an assistant professor at the University of Arizona’s Lunar and Planetary Lab and Principal Investigator of the new mission, tells Inverse.
Under the new name OSIRIS-APophis EXplorer (OSIRIS-APEX), the spacecraft will meet up with Apophis shortly after it passes Earth to take images of the asteroid and study how the brush by Earth might have affected it.
“We know that that close approach, as the asteroid is getting tugged within Earth’s gravitational well, is going to change it,” DellaGiustina says.
Many asteroids are piles of rubble held loosely together by gravity, and Apophis’ pass by Earth might kick off landslides on Apophis and other feature-altering events and change the way it spins.
OSIRIS-APEX will also make a feint at the asteroid by flying close and then burning its thrusters near the surface to blast off rocks and other debris. The goal is to expose the deeper subsurface layers to study them, as well as watch how the debris behaves. Insights from that maneuver should give astronomers a better idea of the material properties of near-Earth asteroids, which could be vitally important in the future should we ever need to protect ourselves from a potential impactor.
After that, DellaGiustina says they might be able to make a soft landing on Apophis and, if everything works out perfectly, perhaps even intercept another asteroid.
“If it’s still operational and we still have the fuel and there’s a new object to go to, I think there might be a third chapter for OSIRIS-REx,” she says.
New horizons for New Horizons
NASA’s New Horizons mission flew by Pluto in 2015 and the Kuiper Belt object Arrokoth in 2019. It is currently voyaging ever farther from Earth on a path that will eventually take it to interstellar space.
But for the next decade or so, until it reaches the heliosphere's edge, New Horizons will be our only spacecraft in the Kuiper Belt. In this vast region, minor planets and other bodies lurk, and we still don’t know much about it or the points just beyond it. Its rarified location and suite of instruments mean the spacecraft should be returning some new data on a little-studied part of our stellar neighborhood and potentially turning up new insights. New Horizons’ instruments can see in infrared through to ultraviolet, analyze the solar wind and interplanetary dust grains, and more.
“It turns out there’s a whole slew of science you can do besides explore the Kuiper Belt with a spacecraft that’s that far from the Sun that you could not otherwise do,” Alan Stern, the Principal Investigator of the New Horizons mission, tells Inverse.
That includes using the spacecraft’s spectrometers to map the heliosphere, a giant bubble formed by plasma from the Sun that extends far out into space. Astronomers can’t observe this from Earth because of the light-blocking dust circulating in the inner Solar System.
New Horizons will also be looking back at Uranus and Neptune to study their atmospheric properties in advance of possible upcoming missions to the ice giants, using its unique vantage point to return data we can’t get from Earth.
The spacecraft has more exotic goals as well, like imaging the cosmic optical background, a diffuse wash of light that emanates from unknown sources in the universe, and searching for free-floating black holes.
Stern and his team are also hard at work looking for another Kuiper Belt object that New Horizons might be able to fly by on its journey. It’s a long shot, Stern says, “but if we don't look, then the odds are precisely zero.”
Eventually, New Horizons will join the Voyager probes in interstellar space, speeding outward into the universe on a one-way journey to infinity. Stern says the spacecraft has enough fuel to remain operational for at least two decades, so we could potentially be tuning in to the wider universe for at least that long. Who knows what we’ll find out there?