Eight Missions are Getting Extensions, Most Exciting: OSIRIS-REx is Going to Asteroid Apophis

NASA has granted mission extensions to eight different planetary missions, citing the continued excellent operations of the spacecraft, but more importantly, the sustained scientific productivity of these missions, “and the potential to deepen our knowledge and understanding of the solar system and beyond.” Each mission will be extended for three more years.

One of the most exciting extensions gives a new mission to the OSIRIS-REx spacecraft, sending it to one of the most infamous asteroids of them all, the potentially hazardous asteroid Apophis.

OSIRIS-REx is currently on its way back towards Earth, and in September 2023, will drop off a sample from the asteroid Bennu, which it orbited for about two-and-a-half years. In October of 2020, the spacecraft successfully touched-down on Bennu, and grabbed a sample.

After it drops off the sample return capsule – which will re-enter Earth’s atmosphere and land under a parachute in Utah — OSIRIS-REx will be renamed OSIRIS-APEX, which is short for OSIRIS-Apophis Explorer.  It will then head out to study near-Earth asteroid Apophis for 18 months.

“Apophis is one of the most infamous asteroids,” said OSIRIS-REx deputy principal investigator Dani DellaGiustina. “When it was first discovered in 2004, there was concern that it would impact the Earth in 2029 during its close approach. That risk was retired after subsequent observations, but it will be the closest an asteroid of this size has gotten in the 50 or so years asteroids have been closely tracked, or for the next 100 years of asteroids we have discovered so far… We were stoked to find out the mission was extended.”

Apophis has a diameter of 370 meters (1,210 feet). During a close flyby of Earth in 2029, it will come within one-tenth the distance between the Earth and Moon – or about 32,000 km (20,000 miles) away.  Observers in Europe and Africa should be able to see it with the naked eye.

OSIRIS-APEX will not collect a sample, but when it reaches Apophis, it will study the asteroid for 18 months, and also collect data along the way. It also will make a maneuver similar to the one it made during sample collection at Bennu, by approaching the surface and firing its thrusters. This event will expose the asteroid’s subsurface, to allow mission scientists to learn more about the asteroid’s material properties, the team said.

The exact details of when the spacecraft will go into orbit around Apophis are still being worked out, but it will be around the time of the Earth flyby in 2029. It plans to study changes in the asteroid caused by its close flyby of our planet.

OSIRIS-APEX will take advantage of the high-resolution camera and instruments on board the spacecraft, snapping images and collecting data to provide an unprecedented study of Apophis.  DellaGiustina, who will become the principal investigator for the new mission, said that the spacecraft was designed “to get up close and personal with the object. Our spacecraft is really phenomenal at that.”

The other mission extensions include several Mars missions: the orbiters Mars Odyssey (in orbit since 2001), Mars Reconnaissance Orbiter (since 2006), MAVEN (2014) and on the surface, the Curiosity rover (aka Mars Science Laboratory, since 2012) and the InSight lander (2018). It is uncertain if and how long InSight will be able to remain in service due to dust accumulation on its solar panels. InSight’s current electrical power production is low, and unless its solar panels are cleared by a passing dust devil or gust of wind.

Other extended missions are for the Lunar Reconnaissance Orbiter, which has been at the Moon since 2008 and New Horizons, which flew past Pluto in 2015 and is currently traveling through the Kuiper Belt, looking for a new object for closer study. It flew past a strangely shaped KBO named Arrokoth in 2019.

NASA  said each extended mission proposal was reviewed by a panel of more than 50 independent experts.  

“Extended missions provide us with the opportunity to leverage NASA’s large investments in exploration, allowing continued science operations at a cost far lower than developing a new mission,” said Lori Glaze, director of the Planetary Science Division at NASA’s Headquarters in Washington. “Maximizing taxpayer dollars in this way allows missions to obtain valuable new science data, and in some cases, allows NASA to explore new targets with totally new science goals.”

Sources: NASA, University of Arizona