Her role is “to decide on the best possible scientific mission to push this asteroid”, says the scientist who also heads the Harvard & MIT Space Consortium, invited this summer to the Fleurance Astronomy Festival (Gers). This reflection under the aegis of the UN is carried out in parallel with NASA’s DART experimental mission, whose ship must hit an asteroid at the end of September, to deviate its trajectory.
What risks should planetary defense allow us to face?
Planetary defense is concerned with knowing what to do in the event of a threat from an asteroid or comet. If we discover an object which is more than 50 meters in diameter and which has more than 1% chance of impacting the earth, we activate the SMPAG advisory group (Space mission planning advisory group, Ed), approved by the scientific committee of the United Nations Council for Outer Space Affairs and composed of space agencies from different countries. If the asteroid is more than 300 meters, we speak of continental impact, and if it is more than a kilometer, 25% of living species would be eradicated. If it is 50 meters, we therefore have a broad national risk.
What methods are considered in the event of an asteroid threat?
It’s definitely not Armageddon, blowing up the asteroid, because creating more pieces is undesirable. It would be possible to ram it and push it thanks to this impact, which the DART missions of NASA and Hera of the European Space Agency (ESA) will test very soon. If the asteroid is very big or you go very late, it would be possible to cause an explosion of a nuclear charge next to the asteroid, thus melting some of the rock which would break off and would push him to the other side, by reaction.
In what legal framework would such an intervention take place?
It is stipulated in the Space Treaty that it is forbidden to send a weapon into space. In addition, the Partial Nuclear Test Ban Treaty prohibits any nuclear explosion. If it turns out that we need to send a nuclear warhead, the United Nations Security Council would have to temporarily override these rules by authorizing a derogation from this treaty. We then find ourselves following the rules specific to the UN Security Council with 15 members, five possible vetoes. Of the 15 members, there must be at least nine who agree without a veto.
How would the decision be made?
Decision-making maps have been developed. The IAWN group (International Asteroid Warning Network, editor’s note), responsible for detecting asteroids and assessing the risks, would warn the United Nations and the SMPAG group as well as the politicians of the country or countries possibly affected. The decision will be taken at the political level on the advice of SMPAG.
Is space affected by current international tensions?