NASA Launches OSIRIS-REx Spacecraft To Intercept Asteroid (cnn.com)

NASA has successfully launched the OSIRIS-REx space probe on Thursday, which aims to take a sample of asteroid Bennu and return to Earth. CNN reports: "The probe is scheduled to arrive at Bennu in August 2018. For months it will hang out -- take pictures, make scans of the asteroid's surface and create a map. Then in July 2020, OSIRIS-REx wil unfurl its 11-foot-long (3.35-meter) robot arm called TAGSAM and make contact with Bennu's surface for about five seconds. During those seconds, the arm will use a blast of nitrogen gas to kick up rocks and dust and then try to snag a sample of the dust and store it. NASA hopes to get at least 2 ounces (60 grams) and maybe as much as 4.4 pounds (2 kilograms) of asteroid dust and small rocks. OSIRIS-REx heads home in March 2021 and arrives back at Earth on September 24, 2023, but it won't land. In a bit of Hollywood-style drama, it will fly over Utah and drop off the capsule holding the asteroid sample. A parachute will guide the capsule to the ground at the Utah Test and Training Range in Tooele County." OSIRIS-REx is an acronym for the objectives of the mission: Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer. It spells the name of the Egyptian god Osiris. The report adds that while the mission is a first for NASA, it is not a first for mankind. "Japan's Hayabusa spacecraft brought back a small sample of asteroid Itokawa dust in 2010."

Comments

Fly over Utah???

[Ecuador]

From the linked project description page it says that 4 hours before atmospheric re-entry, the craft will jettison the sample return capsule and will perform a maneuver to put itself into a stable orbit around the sun. The capsule will re-enter by itself and open a parachute to land. I don't see anywhere that "Hollywood-style drama over Utah" that the summary describes.

Re:what if the E-God Osiris gets mad?

[ShanghaiBill]

In the year 2169, Bennu has a 1/2700 chance of Earth impact. It is too small to be an ELE, but it would be thousands of times bigger than the Chelyabinsk meteor.

Re:Need to rethink some treaty, soon

[rgbatduke]

Gold is currently just under $2000/oz, $32,000/pound, $64,000,000/english ton. With a specific gravity of around 20, one cubic meter of gold in space has a mass of around 20 metric tons, or 24 english tons, so it would be worth ballpark $1,500,000,000. Dropped from orbit to the Earth, it would arrive with (roughly) 32,000,000 Joules/kg of kinetic energy -- 6.4 e11 J total, or around 0.15 kt (360 pounds) of "TNT equivalent" explosive power -- energy that would have to be non-destructively dispersed without melting or vaporizing the metal. To get TO an asteroid to mine it is the big problem. OSIRIS-Rex is costing very close to $1,000,000,000 to launch, and it isn't even CLOSE to complex enough to actually mine it. At this time, the cost per gram of returning with a 60 gram load makes the recovery cost many, many times the cost of gold. That has been true of every single gram of material brought back from space so far. And this does not include the cost of altering the energy and orbit of the asteroid in question which requires fuel at FOB prices at the same location at the asteroid to accomplish or technology that we can imagine but that has yet to be built capable of altering orbits without fuel lifted from the Earth. Finally, if we make the not-too-extreme assumption that meteorites are at least approximately representative of the mineral composition of asteroids, finding a pure gold asteroid is enormously unlikely. Finding an asteroid with a minable gold content bound up the way gold frequently is on Earth is at least somewhat unlikely, although certain kinds of meteors have gold concentrations much higher than normal Earth crustal material in some of their mineral complexes. And finally, gold (or other trace metal) extraction on Earth from anything but raw gold nuggets is chemically toxic and extremely difficult, WITHOUT all of the problems attendant on trying to make it work in the absence of humans (adding human asteroid miners makes the cost increase by a factor of hundreds or more). So -- space opera SciFi aside -- I don't think that there is any real risk of a "space race" even if an asteroid made of (a substantial fraction of) pure gold or platinum in native metal form is found, and it is really rather improbable that one will be found.

But this isn't the real problem. The real problem is that nobody sane is going to let ANYBODY manipulate masses of tens to hundreds of metric tons overheat. 130 metric tons in orbit is 1 kiloton of TNT hitting the ground. It doesn't take a lot of mass up there before one has a "project thor" style weapon, and you KNOW that some Dr. Evil out there would be ensuring a way to make it so. This too has been foreseen by the same SciFi authors of yesteryear, with Heinlein bombarding the Earth with rocks from the Moon using the same launcher that was intended to ship wheat, or Niven and Pournelle's snouts dropping asteroids into the Indian Ocean. Same reason I am very skeptical of proposals to put solar arrays in orbit and beam energy down to the ground via e.g. microwaves. Your multi-gigawatt orbital maser is too easy to repurpose into your multi-gigawatt death ray from space.

I love SF. I've read a really significant fraction of it, although it is difficult to keep up with the recent explosion of e-publishing. But with anything LIKE our existing technology and knowledge of physics, it is just plain difficult to see anything in space that we can afford to reach at a cost that makes it profitable. Anything you can find in space or on the nearby planets can be found, or made, on Earth for a whole lot less, at least so far.

Is this a permanent condition, a fundamental physical reality, of the human species? Hard to say. We are a long, long way away from being able to go into space cheaply, and most of the limitations we had fifty years ago are with us today. If/when fusion becomes a viable energy source with something smaller than warehouse-sized generators, we might see some change, but with chemical rockets and current energy prices and ge

Re:Need to rethink some treaty, soon

[CrimsonAvenger]

If OSIRIS, however, brings back a sample replete with, say, gold or rare earth metals,

A couple of things:

Gold isn't worth enough to go after in an asteroid. Yet.

"Rare Earths" aren't actually rare. What they are is better described as "dispersed" - no ores with lots and lots of them to find, just dig up some ground, and sift out the very small amounts of "rare earths". So they wouldn't be worth going after either.

If asteroid mining ever makes it big, it'll be because asteroids provide things like iron and aluminum that are already at the top of the gravity well. Building things in space is much easier if you don't have to lift it from the ground to start.

Note, by the by, that in terms of deltaV required to move things into LEO, the asteroids are closer than the Earth is....