Just a few weeks ago it was announced that scientists in our research group at the University of Manchester are among only 11 selected international groups to be allocated a number of sought after particles returned by the Hayabusa mission! This Japanese mission was the first to return material from an asteroid to Earth. So congratulations to members of our group, Henner Busemann (lead proposer), Nicole Spring and Jamie Gilmour (who is involved also in two further international consortiums). This is a very exciting opportunity and a great success for our school and we can’t wait to have a look at this material.
The Hayabusa (Japanese for “Peregrine Falcon”) mission was long assumed to be a star-crossed failure as many problems – including damage in space, complete loss of contact, and the reduction of time near the targeted asteroid – had to be overcome.
Amazing persistence combined with engineering skills allowed JAXA, (the Japanese answer to NASA) to surprise all those who were still in doubt of the ultimate success of this mission. Three years later than originally planned, Hayabusa returned an estimated 1500 grains from the asteroid Itokawa to Earth.
This mission achieved a lot of “firsts”. It’s the first sample return mission run by Japan, and the first material directly returned from a known asteroid to Earth. While meteorites sample a large variety of parent bodies in the asteroid belt, exactly which celestial object each meteorite originated from is difficult to establish. Asteroid Vesta, the second largest body in the asteroid belt, might be the only case where researchers believe to know the asteroidal source of meteorites in their collections.
These meteorite collections contain a large number of samples (>4000) that are classified as “LL chondrites”; “LL” stands for low in iron and low in metal, and “chondrites” for a class of meteorites that shows melted roundish mm-sized objects, called “chondrules”. These “chondritic” meteorites are considered the most pristine samples, surviving relatively unaltered since the formation of the solar system. Careful initial examinations including mineralogical, chemical, isotopic and spectroscopic analyses proved that Hayabusa samples are similar to the LL meteorite class, and, more specifically, categorised as “type 4-6”. These numbers indicate that the material has experienced some heating on its parent body (types 1 and 2 indicate aqueous activity and type 3 means the material has remained essentially unheated).
LL chondrites are part of a bigger group known as “ordinary” chondrites as they make up 87% of all meteorites found. It is perhaps disappointing that the type of material returned by the mission is so “common” and, if delivered by a meteorite, would not be anything to write home about. However, the fact that it was brought back “fresh” from the source creates excitement among scientists. It is now possible to examine material that has not been in contact with the Earth’s environment. Furthermore, it can be linked to Itokawa, an asteroid with known orbit, physical and geological properties.
Stay tuned for the description of the sample’s arrival in Manchester and our first examinations…