Planetary Defense Conference (PDC) 2017 – Day 5

Friday, May 19, 2017, Tokyo, Japan

The last day of the PDC was fully dedicated to the hypothetical NEO/Earth impact event scenario exercise.

During the whole week the experts worked on this exercise that aims to deflect the fictitious asteroid 2017 PDC.

planetary defense conference pdc 2017 day 5

Orbit of Asteroid 2017 PDC

The initial scenario was as follows:

  • An asteroid is discovered on March 6, 2017, at magnitude 21.1, and confirmed the following day. It is assigned the designation “2017 PDC” by the Minor Planet Center.
  • Initial calculations indicate that 2017 PDC’s orbit approaches well within 0.05 au to that of the Earth, and it is therefore classified as a Potentially Hazardous Asteroid (PHA). The orbit is eccentric, extending from a distance of 0.88 au from the Sun at its closest point to 3.60 au at its farthest point. The asteroid’s orbital period is 1225 days (3.35 years), and its orbital plane is inclined 6.3 degrees to the orbit of the Earth.
  • The day after 2017 PDC is discovered, JPL’s Sentry impact monitoring system, along with ESA’s similar CLOMON system, both identify several future dates when this asteroid could potentially impact the Earth. The date of the most likely potential impact is July 21, 2027 – over ten years away – but the probability of impact is very low, about 1 chance in 40,000.
  • When first detected, the asteroid is about 0.36 au (54 million kilometers or 33 million miles) from Earth, approaching our planet and getting brighter. It is observed extensively, and as the observational dataset grows, the impact probability for 2027 increases. The asteroid peaks in brightness at magnitude 20.4 on April 7, by which time the impact probability has risen to nearly 0.2 percent.
  • Very little is known about the asteroid’s physical properties. Based on the apparent visual magnitude, its absolute (intrinsic) magnitude is estimated to be about H = 21.9 +/- 0.4. But since its albedo (reflectivity) is unknown, the asteroid’s mean size could be anywhere from 100 meters to over 250 meters.
  • 2017 PDC approaches the Earth for well over a month after discovery, and it reaches its closest point of about 0.13 au in late April. Unfortunately, that is too far to be detected by Goldstone radar, and too far south for Arecibo radar. The asteroid is not expected to pass close to the Earth again, until the potential impact in 2027.
  • Observers track the asteroid almost daily since discovery, and the impact probability for 2027 continues to rise. As of May 15, 2017, the probability of impact has reached about 1%.

Every day new information and guidelines were introduced, in order to create an exercise as close to a real situation as possible.

Important to mention that the whole exercise is completely fictional and does NOT describe an actual potential asteroid impact.

You can find all the detailed information about the exercise, including the final results, here.


The PDC comes to an end. It was a great event, bringing together experts from all over the world to discuss the threat to Earth posed by asteroids and comets and actions that might be taken to deflect a threatening object.

It is very inspiring to see people from different cultures, backgrounds and speaking different languages, coming all together to discuss about a common threat to all of us.

The Planetary Defense Conferences are extremely important and the NEOShield-2 team could not be prouder of participating in it and contributing to protect Earth from the next major asteroid impact.

planetary defense conference pdc 2017 day 5

From left to right:
Martin Schimmerohn (Fraunhofer EMI), Kilian Engel (Airbus DS), Siegfried Eggl (NASA/JPL), Line Drube (DLR), Daniel Hestroffer (OBSPM), Albert Falke (Airbus DS), Simon Delchambre (Airbus DS) and Alan Harris (DLR).


You can watch all speeches and the exercise here.

Check the full list of the NEOShield-2 participation here.

Check also Day 1, Day 2, Day 3 and Day 4.

About the author: VR