With the success of the OISRIS-Rex mission to asteroid Bennu, and with scientists studying the samples that were returned, the spacecraft has a new mission as OSIRIS-APEX, and Canada has a role to play.
When the OSIRIS-REx returned its canister to Earth with samples from asteroid Bennu, scientists were anxious to begin studying the regolith. Once the canister was opened on October 11, 2023, scientists were thrilled that the amount collected, 121.6 grams, was a little more than double the 60 grams they had hoped for.
Now as scientists examine Bennu’s regolith, the spacecraft and its instruments has a new mission.
Onward to Asteroid Apophis
NASA says that OSIRIS-APEX “is a mission to study the physical changes to asteroid Apophis that will result from its rare close encounter with Earth in April 2029.”
In 2029 Apophis’ orbit will bring it within 32,000 kilometers of Earth’s surface, about about 1/10th of the distance to the Moon. NASA said “our planet’s gravitational pull is expected to alter the asteroid’s orbit, change how fast it spins on its axis, and possibly cause quakes or landslides that will alter its surface.”
The OSIRIS-APEX spacecraft will try and get within 5 metres of the asteroid’s surface and “fire its thrusters downward, stirring up surface rocks and dust to give scientists a better understanding of the composition of the asteroid” according to the Canadian Space Agency (CSA).
The spacecraft can no longer collect and return samples as the only canister onboard was used for OISRIS-Rex. The OSIRIS-APEX mission is a bonus mission as the spacecraft was still in good shape after the conclusion of its original mission.
The OSIRIS-APEX mission objectives include:
- Study changes to asteroid Apophis’s surface, orbit and rotation resulting from Earth’s gravitational pull
- Analyze how objects such as Apophis (a “stony” asteroid) can change over time as they interact with Earth’s gravity during multiple encounters
- Map Apophis’s surface and analyze its chemical composition
- Collect data on Apophis to help better understand potentially hazardous asteroids (those whose orbits come within 7.4 million kilometres of Earth)
Canada’s Role in OSIRIS-APEX
As with the OSIRIS-REx mission, the Canadian built OSIRIS-REx Laser Altimeter (OLA) instrument will once again be used to take measurements and create a 3D map of Apophis.
The CSA stated that generated “around 3 billion individual measurements” for the OSIRIS-REx, this despite one of two lasers failing. OLA has two lasers, a high-energy laser transmitter (HELT) and a low-energy laser transmitter (LELT). The low-energy laser instrument is the one that failed. Despite the failure though, OLA was able to create a spectacular 3D map of asteroid Bennu.
