OSIRIS-REx flies on as OSIRIS-APEX to explore its second asteroid

After seven years in space and over 4 billion miles traveled, NASA’s OSIRIS-REx mission efficiently collected and delivered the primary U.S. pattern from a near-Earth asteroid. But, in spite of everything this time and journey, the spacecraft is not going to retire.

As a substitute, NASA prolonged the College of Arizona-led mission in order that the spacecraft can be utilized to review one other near-Earth asteroid named Apophis. The mission was renamed OSIRIS-APEX, brief for OSIRIS-APophis EXplorer. An overview of the mission was revealed in The Planetary Science Journal.

OSIRIS-REx deputy principal investigator Dani DellaGiustina is now the principal investigator for the OSIRIS-APEX mission.

Twenty minutes after dropping the pattern excessive above Earth’s environment on Sept. 24, the spacecraft fired its thrusters to place it on target to rendezvous with Apophis in 5½ years—simply after Apophis makes its personal shut strategy to Earth. This path consists of three Earth gravity assists and a number of other nail-bitingly shut laps across the sun.

By April 2, 2029, the spacecraft cameras will start gathering information because it approaches the asteroid. Apophis may also be intently noticed by Earth-based telescopes. However within the hours after the shut encounter, Apophis will seem too close to the sun within the sky to be noticed by Earth-based optical telescopes. This implies any adjustments triggered by the shut encounter might be greatest detected by spacecraft.

The spacecraft will catch as much as the asteroid on April 13, 2029, because the asteroid whizzes 20,000 miles above Earth’s floor. Scientists will then spend the subsequent 18 months learning the asteroid intimately. They will additionally disturb the fabric on the floor with the spacecraft to disclose what lies simply beneath.

“Apophis is an notorious asteroid,” mentioned DellaGiustina, who’s an assistant professor of planetary sciences on the UArizona Lunar and Planetary Laboratory.

“When it was found in 2004, there was a scare that it was going to influence the Earth in 2029, however that threat was retired. Then there was one other scare that it was going to influence the Earth precisely seven years later, in 2036, however observations mixed with modeling now present that Apophis would not pose a threat for not less than the subsequent 100 years. Regardless of this, Apophis nonetheless has this position within the psyche of all of us who research this stuff. Whereas it is not going to influence the Earth in 2029, nonetheless, it does get very shut.”

The 340-meter-wide Apophis is a stony, or S-type, asteroid manufactured from silicate supplies and nickel-iron, that are completely different than C-type asteroids like OSIRIS-REx’s first goal, Bennu, that are wealthy in carbonaceous materials.

Apophis possible shaped from a collision of a father or mother physique within the asteroid belt that knocked it towards Earth’s neighborhood. The asteroid will move nearer than a few of Earth’s orbiting satellites and one-tenth the gap to the moon. That is the closest approach by an asteroid of this measurement in trendy historical past, and it is going to be seen to the bare eye within the Japanese Hemisphere.

An asteroid of this measurement coming so near Earth is uncommon, occurring roughly as soon as each 7,500 years.

The mission thought of visiting different targets—even Venus—however Apophis was chosen, as a result of it was the one object that the spacecraft may intently rendezvous with, DellaGiustina mentioned. The shut strategy permits scientists to review interactions with Earth’s gravitational forces, particularly tidal forces that would disturb its floor to disclose what lies beneath.

“Apophis will get shut sufficient that there’s some quantity of exercise that we’re anticipating on its floor,” DellaGiustina mentioned. “There could be landslides or particle ejections that create a comet-like tail. The shut strategy is a good pure experiment.

“We all know that tidal forces and the buildup of rubble pile materials are foundational processes that would play a task in planet formation. They might inform how we bought from particles within the early solar system to full-blown planets. Our greatest guess proper now could be that Apophis is, certainly, a rubble pile.”

Mission science objectives are primarily based on what is thought about Apophis from ground-based observations, the group’s experiences at Bennu and present information for different S-type asteroids. In the end, the group hopes to grasp the asteroid’s evolution and traits, together with Apophis’ materials power, porosity and density. All they study can inform planetary protection analysis, particularly as a result of a lot of the probably hazardous asteroids are additionally S-type asteroids like Apophis.

“We discovered lots at Bennu, however now we’re armed with much more questions,” mentioned Amy Simon, OSIRIS-APEX mission undertaking scientist and senior scientist for Planetary Atmospheres Analysis within the solar system Exploration Division on the NASA Goddard Area Flight Middle.

For instance, as deputy instrument scientist for the OSIRIS-REx Seen and near-IR Spectrometer, Simon and colleagues detected clay minerals and organics on Bennu, suggesting that the asteroid interacted with water previously. Scientists predicted discovering these on C-type asteroids like Bennu however have been unable to detect it from ground-based observations.

Simon mentioned she’s excited to see how Apophis appears completely different from expectations and from carbonaceous asteroids Bennu and Ryugu, which Japan visited with the Hayabusa 2 probe in 2018.

Getting up shut and private with these asteroids presents a novel alternative for planetary scientists. At the moment, scientific understanding of solar system formation is closely knowledgeable by meteorites, that are items of different celestial our bodies that fall to Earth.

Asteroids are the first father or mother our bodies of meteorites however are often noticed from so distant that they seem solely as factors of sunshine within the sky that reveal little about their world properties or floor variability.

The OSIRIS spacecraft science devices have been particularly designed to attach our understanding of meteorites to their father or mother asteroids by putting meteorite-scale rocks into geologic context on asteroids and investigating asteroids’ geologic processes at Bennu and really quickly at Apophis.