Like #Toutatis, #Apophis is a tumbling contact-binary ordinary chondrite asteroid.

But Apophis is less than 10% the length of Toutatis and is thousands of times less massive.

Marta Ceccaroni has analyzed the effect of the #Apophis flyby in 2029 on debris in the graveyard orbits past geosynch.

Collision avoidance planning may need to take the perturbations into account - up to ~10 m in months after the flyby.

The #Apophis T-4 workshop wraps up with discussions about talking to the public about the flyby.

And cautions about the expected amount of disinformation.

"Apophis Communications Challenge" - https://www.hou.usra.edu/meetings/apophis2025/technical_program/?session_no=204

In the next session of the #Apophis T-4 workshop; Wing Ip relates that Huang Jiangchuan, lead engineer for Chang'e 2, has a mission concept for a cubesat to be placed where Apophis would run by it: https://www.hou.usra.edu/meetings/apophis2025/pdf/2023.pdf .

But, as for other proposals, funding is uncertain.

#Apophis T-4 continues today reviewing many other proposed space missions to the asteroid; in addition to the two spacecraft that are being built for that & the one that is already in the sky: https://www.hou.usra.edu/meetings/apophis2025/technical_program/?session_no=201

Three spacecraft may be enough, but there has been a lot of work on this.

The DESTINY+ team also presented a potential trajectory that would fly by #Apophis, then by #Phaethon, and then by #2024YR4.

But if this will be possible or not depends on the exact launch date out of Tanegashima.

The DESTINY+ mission team propose to launch that spacecraft in 2028; fly by #Apophis before the asteroid makes its flyby of Earth; and then go on to the asteroid Phaethon.

Per Tomoko Arai: https://www.hou.usra.edu/meetings/apophis2025/pdf/2061.pdf

The last session at the #Apophis T-4 workshop today is reviews of the #OSIRISAPEx and #RAMSES spacecraft and what they are planned to do at the asteroid:

https://www.hou.usra.edu/meetings/apophis2025/pdf/2019.pdf
https://www.hou.usra.edu/meetings/apophis2025/pdf/2012.pdf

In planning optical observations of #Apophis between now and 2029; the possibility of Hubble no longer being available has to be considered.

All things are impermanent.

Cristina Thomas reviews optical observing plans for #Apophis in 2027 and 2028; to provide the best possible information prior to the flyby: https://www.hou.usra.edu/meetings/apophis2025/pdf/2066.pdf

#TeamRadar #Apophis planning page, with the hope that we can do all of this 4 years from now: https://echo.jpl.nasa.gov/asteroids/apophis.2029.goldstone.planning.html

#TeamRadar presentations at #Apophis T-4:

Benner et al., "Goldstone Radar Observations of 99942 Apophis in 2029: Detailed Plans" - https://www.hou.usra.edu/meetings/apophis2025/pdf/2058.pdf

Horiuchi et al., "Southern Hemisphere Asteroid Radar Program (SHARP) and the Apophis Encounter in 2029" - https://www.hou.usra.edu/meetings/apophis2025/pdf/2037.pdf

From the posters at the #Apophis T-4 workshop:

Titus et al., "Potential Terahertz and Microwave Observations of (99942) Apophis from Ground-Based Telescopes" - https://www.hou.usra.edu/meetings/apophis2025/pdf/2017.pdf .

Describing how to observe the asteroid with ALMA; with comparison to other ALMA asteroid projects.

Oscar Fuentes-Muñoz, "Close Encounter Statistical History of 99942 Apophis" - https://www.hou.usra.edu/meetings/apophis2025/pdf/2057.pdf

2029 may be the closest approach #Apophis has ever made to Earth.

It has also been nearly 20 years now since I got to help observe #Apophis with the Arecibo Observatory as a #TeamRadar summer student.

Woah.