#pdc2025 — Public Fediverse posts

The Viking is raiding - what a great outing by Harrysson.
Making a huge jump in the World Ranking! #pdc2025

#PDC2025 also had multiple comments about "planetary defense" as a term being confusing, as well as far too military.

And that would be why I personally prefer to simply talk about the impact hazard.

#PDC2025 wraps up with a question-and-answer session.

Question: "What about SpaceX?"

Answer: SpaceX has no plans for doing anything beyond Earth orbit. It just sells rockets to the agencies that do.

For anyone wondering:

The #PDC2025 asteroid impact hypothetical scenario progresses with the possibility of a partial deflection; moving the asteroid south to airburst harmlessly over the southern ocean.

Compare to what actually happened on 1963 August 3: https://link.springer.com/article/10.1007/s11038-007-9173-3.

#PDC2025 continues today with discussion of the importance of providing accurate information about the impact hazard: https://iaa.4hdt.ro/event/1/contributions/57/ .

From things like real images of actual asteroids to "don't immediately run to the window to see what that flash was" if there is another Chelyabinsk.

#PDC2025 features a few talks about having small satellites left on orbit to fly past any asteroids that may require investigation.

Precedents here are Comet Interceptor and also Chang'e 2 flying by Toutatis in 2012; although it was not designed for that.

Steve Chesley describes the heliocentric orbit change for Didymos from the #DARTMission impact, rather that the orbit change of Dimorphos about Didymos.

~12 microns/second, measured by occultation timing.

Lots of science from chasing shadows.

#PDC2025

#PDC2025 resumes with @schmemela leading discussion of different asteroid deflection methods; including both the #DARTMission & other work on kinetic impact deflection and things like gravity tractor deflection.

Thobekile Sandra Ngwane, University of Cape Town:

"The Rapid-Response Fully-Automated NEA Follow-Up Program with the SAAO's 1-m Lesedi Telescope" - https://iaa.4hdt.ro/event/1/contributions/99/

#PDC2025

. @asrivkin et al. at #PDC2025 : "JWST As a Tool for Early Characterization of Potential Impactors" - https://iaa.4hdt.ro/event/1/contributions/131/

Considering #2024YR4 and other objects.

Direct attention to all of the other reasons letting companies unilaterally make a mess of low orbit is a bad idea.

Like how the Starlinks are disrupting the operations of weather satellites in LEO.

QT Michael Busch @michael_w_busch
2025 May 7

#PDC2025 reviews the impact of satellite streaks on the asteroid discovery surveys.

They continue to be a nuisance; but are manageable. And they remain concentrated into twilight data where detections were already tricky.
https://mastodon.online/@michael_w_busch/114465581586839589

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.

#PDC2025

#TeamRadar presentations at #PDC2025, continued:

Pupillo et al., "Radar Observation of Asteroids 2005 LW3 and 2006 WB with European Radio Telescopes" - https://iaa.4hdt.ro/event/1/contributions/111/ .

Venditti et al., "The potentially hazardous binary asteroid (285263) 1998 QE2" - https://iaa.4hdt.ro/event/1/contributions/150/

#TeamRadar presentations at #PDC2025 :

Benner et al., "Status of Near-Earth Asteroid Radar Observations at Goldstone" https://iaa.4hdt.ro/event/1/contributions/140/

Brozovic et al., "3D shape model and spin state of 99942 Apophis estimated from 2013 radar and lightcurve data" https://iaa.4hdt.ro/event/1/contributions/9/

Calves et al., "Radar and optical tracking of Near-Earth Objects at the University of Tasmania" https://iaa.4hdt.ro/event/1/contributions/105/

Horiuchi et al., "Southern Hemisphere Asteroid Radar Program (SHARP)" https://iaa.4hdt.ro/event/1/contributions/17/

Leviticus Lewis, now formerly of FEMA, reminds everyone at #PDC2025 about the importance of establishing and maintaining effective disaster-response organizations.

For all natural disasters and hazards. Not just rocks falling from the sky.

There is quite a bit of discussion at #PDC2025 about the indirect effects of asteroid impacts.

For example, several presentations by Tim Titus' group about things from distant tsunami to supply chain disruptions:
https://iaa.4hdt.ro/event/1/contributions/65/
https://iaa.4hdt.ro/event/1/contributions/74/
https://iaa.4hdt.ro/event/1/contributions/59/

Erasmus, Ngwane, et al. will be reviewing asteroid astronomy from the South African Astronomical Observatory at #PDC2025; particularly results of work with ATLAS and SALT - https://iaa.4hdt.ro/event/1/contributions/151/ .

#PDC2025 also includes discussions of current laws and regulations relevant to any asteroid deflection.

Seenu Tiwari points out potential liability from any debris created by a deflection mission - debris which could pass near Earth, even if missing it: https://iaa.4hdt.ro/event/1/contributions/238/

Justin Atchinson reviews for #PDC2025 how one can retask spacecraft originally intended for something else to visiting a potentially hazardous asteroid.

The precedent here is OSIRIS-APEx, which returned samples of the asteroid Bennu but will also visit Apophis (and Apophis will miss the Earth).

The #PDC2025 hypothetical impact scenario has two options for deflection away from Earth; both of which have large groups of people living in locations at risk in the event of a partial deflection.

This is the moderators demonstrating a form of the "deflection dilemma".

@uastronomer

It was good to learn about this from Humbulani Mudau at #PDC2025 today.

Davide Farnocchia reviews #2024YR4:

63 observatories, >500 observations.

3.8% chance of lunar impact in 2032 December, with the last observations for this year still pending.

It will likely require waiting until 2028 to resolve the lunar impact possibility. But it cannot impact Earth.

#PDC2025

International efforts to address the impact hazard are coordinated by the International Asteroid Warning Network (https://iawn.net/) and the Space Mission Planning Advisory Group (https://www.cosmos.esa.int/web/smpag).

IAWN was recently activated for the case of asteroid #2024YR4: https://iawn.net/obscamp/2024YR4/index.shtml
#PDC2025

#PDC2025 begins with remarks by Humbulani Mudau, CEO of SANSA, who emphasizes the connections between different fields when addressing the asteroid impact hazard.

#PDC2025 will be streaming at https://www.youtube.com/watch?v=OIz_MGOfWxA , for anyone wanting to watch it who is not registered as a participant.

The Planetary Defense Conference starts early in the morning for those of us calling in from the Americas: https://iaaspace.org/event/9th-iaa-planetary-defense-conference-2025/

The #PDC2025 hypothetical asteroid scenario is only a test.

It is also an exercise in alternate history; with a point of divergence on 2024 June 5: https://cneos.jpl.nasa.gov/pd/cs/pdc25/ .

Differences from reality beyond the impact hazard are left as an exercise for the reader.

#PDC2025 will have the perennial hashtag collision between the asteroid impact hazard meeting and the darts competition.

When addressing the impact hazard, we have had only one DART.

Next month, space agencies will conduct a test of how we might react to a hypothetical asteroid impact: https://cneos.jpl.nasa.gov/pd/cs/pdc25/epoch2.html

This is part of the Planetary Defense Conference.

#PDC2025 is being hosted by SANSA in Cape Town and online: https://iaaspace.org/event/9th-iaa-planetary-defense-conference-2025/

This is only a test.

The #PDC2025 hypothetical impact scenario is also an alternate history:

It imagines a ~130 m Earth-impacting asteroid having been discovered on 2024 June 5 with a 2041 impact.

Again: This is only a test.

This is a test.

The Planetary Defense Conference is happening again in May: https://iaaspace.org/event/9th-iaa-planetary-defense-conference-2025/.

The hypothetical impact scenario to be played through during the meeting is now available at https://cneos.jpl.nasa.gov/pd/cs/pdc25/.

This is only a test.

#PDC2025