JAXA has confirmed the engine burn to allow Ryugu to capture Hayabusa 2. Up close, the asteroid doesn’t look quite as clearly octahedral, but it’s still showing a remarkable diamond silhouette. The surface is battered, but not in the manner we’re used to seeing with larger bodies. The craters have soft edges, and the surface in general looks more like a clump of fine particles with occasional rocks stuck in it, probably reflecting a relatively loose composition.
The spacecraft is expected to stay at Ryugu for 18 months, during which it will make a series of daring touch-and-go landings, deploy a series of landing vehicles, and even launch an impactor at the asteroid. It will also attempt to collect material using a feed horn device similar to that used on the original Hayabusa. At the end of its stay, Hayabusa 2 will fire its engines to leave orbit around Ryugu and head back to Earth, with arrival scheduled for 2020. The original mission returned only a tiny amount of material, but enough to make comparisons to what Hayabusa 2 will return. The exciting part of the mission is only just beginning!
The second Japanese asteroid sample return mission is underway, and it’s spotted its target, the Apollo-group asteroid 162173 Ryugu. And what do you know? Most asteroids so far have looked like potatoes, but this one makes me think of an eight-sided die:
These images, taken with the ONC-T (Optical Navigation Camera – Telescopic) instrument at ranges from 330 to 240 km as the spacecraft approaches the asteroid, show that Ryugu is spinning like a top, completing one revolution every 7.6 hours.
Hayabusa 2 is expected to enter orbit around Ryugu next week, and will commence a lengthy period of orbital observations leading up to a series of daring landings in which it will sample material from the asteroid. It will also deploy a number of mini spacecraft, including an impactor (with an explosive charge) to excavate fresher material for sample, a German/French hopping lander named MASCOT and partially based on the design of Philae (the piggyback lander from the Rosetta mission), and three Japanese rovers. It’s an ambitious mission, and we’ll soon start to get into the interesting bit. 😉
OSIRIS-REx, the hotly anticipated asteroid sample return mission bound for asteroid 101955 Bennu, has blasted off from Cape Canaveral Air Station’s SLC-41!
Rocketcam footage of liftoff:
Full launch through Centaur MECO-1:
The rocket coasted halfway around the Earth after that, then relit Centaur for a second burn, and about forty-five minutes after launch, MECO-2 left it on an Earth escape course. A fifteen minute coast then brought the vehicle within range of the tracking station in Canberra, Australia, and then the spacecraft was released. At this point, OSIRIS-Rex has a solar orbit actually not too much different than the Earth itself. This is by design; Bennu is an Earth-crossing asteroid, belonging to a class of bodies called Apollos. So they don’t want to get too far away from Earth orbit or they will be going far too quickly when they encounter Bennu. In about a year, OSIRIS-REx will briefly return for a gravity assist maneuver, stealing a tiny bit of the Earth’s momentum to propel it to a collision course with Bennu. Then, nearly a year after that, the spacecraft will arrive at Bennu.
OSIRIS-REx is spending a long time at Bennu; the window for Earth return will not open until 2021. So it will make good use of its time until then, mapping and investigating the carbonaceous (rocky) asteroid, selecting a site from which to collect a sample, and then gingerly flying up to the asteroid to collect the sample. Bennu is too light for a spacecraft to meaningfully land on it; its gravity is very slight. The concept is broadly similar to that of the Hayabusa spacecraft, which sampled the asteroid 25143 Itokawa in 2005 and returned the particles to Earth in 2010. However, the collection mechanism is different. Hayabusa had difficulties with its collector, and did not retrieve as much material as had been hoped; let’s cross our fingers for OSIRIS-REx to have better luck!
The mission does seem blessed so far — not only did the spacecraft survive the Falcon 9 pad explosion just a mile away, but the mission itself is $30 million under budget. During the cruise, the team will have the pleasure of deciding what to do with that extra money. Hire more scientists to make better use of the time they’ll have at Bennu? Additional studies during the cruise phases? A mission extension for the spacecraft after the canister is returned, a la Genesis? It will be fun to see what they come up with. 😉
Dawn is now close enough to resolve details on dwarf planet 1 Ceres! JPL released this amazing animation showing the small world’s rotation:
And just think — this will only get better as Dawn approaches. The best will come in the spring, though, when Dawn enters orbit. I can’t wait!