Sometimes it seems as if the history of spaceflight is a long exercise in oneupsmanship with each agency trying to top the others. Case in point is Japan's Hayabusa2 mission, which, following the landing of Philae on on comet 67P/Churyumov–Gerasimenko last month, the Japan Aerospace Exploration Agency (JAXA) confirmed was successfully launched today at 1:22:04 pm JST from the Tanegashima Space Center on a mission to not only land on an asteroid, but to bomb it.

According to JAXA, the unmanned Hayabusa 2's liftoff atop its H-IIA rocket went off without a hitch and the spacecraft achieved its Earth-escape trajectory one hour, 47 minutes and 21 seconds into the flight. It will now spend the next year orbiting the Sun before making a flyby of the Earth, which will boost it to a high enough speed to rendezvous with the C-type asteroid 1999 JU3 in July 2018.

The second in the Hayabusa asteroid explorer series, Hayabusa2 uses technology based on the successful Hayabusa mission launched in 2010. Equipped with ion thrusters, the unmanned probe is headed for JU3, which it will study with a variety of instruments in the hopes of learning more about the origins of the Solar System and recovering organic materials from the asteroid's interior.

Aside from the usual imagers and spectroscopes, JAXA says that Hayabusa2 will be taking a more direct approach toward asteroid studies. Like its predecessor, Hayabusa2 has a probe with a sample grabber, which it will use to collect pieces of the asteroid's surface. These will be transferred to a reentry vehicle and fired back into the Earth's atmosphere when the asteroid explorer returns home after completing its 18-month stay at JU3.

In addition, Hayabusa2 also carries a small fleet of landers for surface studies. These include a pair of Minerva II rovers, which are designed to bounce slowly across the surface of the 900 m (3,000 ft) asteroid in its tiny gravity, and the MASCOT lander, which will deliver a suite of four instruments supplied by the German aeronautics and space research center (DLR) and the French Space Agency (CNES).

But the most spectacular experiment of the mission is the Small Carry-on Impactor (SCI), which is basically a space-going bazooka warhead. The SCI consists of a shaped explosive charge formed into a cone with a 2 kg (4.4 lb) liner made of copper. When the SCI is fired at the surface, the charge will detonate and the copper will turn into a molten slug that will blast open a crater in the asteroid, exposing buried material that has been protected from sunlight and damaging radiation for billions of years.

Haybusa2 is scheduled to return to Earth in 2020.

The video below shows the orbital trajectory of Hayabusa2 as it chases JU3.

Source: JAXA

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