Not as cool as a Super Blood Wolf Moon but...
January 28, 2019 5:37 AM   Subscribe

From Arizona Public Media: “OSIRIS-Rex timeline” (video, 6½ min), OSIRIS-Rex^ being NASA's first automated sample return mission from an asteroid, sent to 101955 Bennu, a carbonaceous near-Earth body, and anticipated to arrive back on Earth in September. 2023 The spacecraft rendezvoused with its target and imaged it in early December, remained in orbit studying the asteroid. Surprising discoveries so far have included the observation of water-bearing minerals and of sizeable impact craters.

AZPM produced a longer piece “OSIRIS-REx: Countdown to Launch” (video, 26 min, alt link) covering the design, construction, and September 2016 launch of the probe and plans a comprehensive account of the entire mission to be released later this year.

Humankind's first successful asteroid sample-return mission was Japan's Hayabusa probe (はやぶさ, "Peregrine falcon", Hayabusa program previously 1, 2, 3, 4) to silicaceous asteroid 25143 Itokawa and before that NASA's Stardust spacecraft collected particles from a comet's coma.

During the 1970s, following the manual sample collections by the astronauts of the earliest Apollo missions, the first successful automated sample-return missions from extraterrestrial bodies in history were the Soviet Union's Luna / Луна lunar landers and rovers.

The Soviets planned a Martian sample-return mission late in the 70s but it was canceled. We have yet to successfully return physical samples from the surface of the Red Planet.
posted by XMLicious (15 comments total) 12 users marked this as a favorite
posted by odinsdream at 6:27 AM on January 28, 2019 [1 favorite]

posted by doctornemo at 6:39 AM on January 28, 2019

I've seen enough kaiju movies to know where this is going.
posted by TheWhiteSkull at 6:40 AM on January 28, 2019 [3 favorites]

posted by Fizz at 7:21 AM on January 28, 2019

Am I misreading this? The mission is ongoing and the samples have not yet been collected and will return in Sep 2023. From the Rex link:

OSIRIS-REx will spend two years mapping Bennu, a potentially hazardous asteroid that could one day threaten Earth.

The maps will be used to select the site where the spacecraft will use its robotic arm to collect regolith, or loose dust and broken rocks from the surface of the asteroid. The sample will weigh at least 2.1 ounces (59.5 grams)

The sample will be stored on the spacecraft and returned to Earth in September 2023.
Mission Elapsed
posted by jclarkin at 7:27 AM on January 28, 2019 [1 favorite]

No? We read the same thing you did...
posted by agregoli at 7:51 AM on January 28, 2019

Are you saying that this isn't sufficiently cool for you??
posted by odinsdream at 8:10 AM on January 28, 2019

So the post is incorrect in saying that the probe has started its return journey?
This is very cool, but the mission is basically just started.
posted by jclarkin at 8:10 AM on January 28, 2019

Bah. Yeah, sorry everyone, my pre-coffee brain somehow glitched every time I came across "2023" I guess and I got the impression it was one of those things where it was going to take a long time catching up to the asteroid but then return quickly and then also misconstrued the "inbound on Earth-gravity assist" bit. Thanks jclarkin.

So if a mod feels like changing "in September" to "in September 2023" and deleting ", and recently embarked on its return journey"... Also I improperly capitalized "OSIRIS-REx" above the fold: the 'E' should be caps
posted by XMLicious at 8:13 AM on January 28, 2019

[Made requested edits. ]
posted by restless_nomad (staff) at 8:17 AM on January 28, 2019 [2 favorites]

The asteroid Bennu is about 500 meters in diameter, with a surface gravity of just 10 micro-g.

The current orbit of 62 hours at 5 cm/sec is about 11 km in circumference, or 4 km per day. Slow!

Since Bennu isn't a sphere, it has to be complicated to design an approach close enough to use a robot arm.
posted by jjj606 at 8:26 AM on January 28, 2019

I don't know about y'all, but I definitely look forward to Bennu coming to visit our little home.
posted by GoblinHoney at 8:58 AM on January 28, 2019

So, anecdote here. NASA's New Frontiers program ("medium-cost robotic space exploration missions capped at $1 billion") had a call for proposals that consumed the lives of our planetary scientists. There were eventually 12 proposals, all very cool (A boat to sail on Europa! A quadcopter to fly on Titan!) that went into the Stage 1 competition, vying for the grand reward of ... getting to write a longer proposal for Stage 2. (Sigh.)

And then NASA defied expectations that there would be 4 finalists, and picked just 2 missions to study further. One is the aforementioned quadcopter on Titan - it's called Dragonfly, and if I wasn't contractually obliged to not say nice things about it, I'd admit that it's a pretty freaking neat idea. The other one, led by the folks one floor below me, is the Comet Astrobiology Exploration Sample Return Mission (CAESAR) - and it's quite a program. See, we've flown through a comet's halo, we've sampled an asteroid, and OSIRIS-Rex will bring a chunk of rock back to Earth. But for real astrobiology, you want a sample of a primordial ice from the formation of the Solar System, and you want it - this is the killer - still frozen. Because as comet ice thaws, it releases the trapped gases and there's chemistry that fundamentally alters the composition.

So: the ambition for CAESAR is to return a chunk of comet ice, still frozen and chemically unaltered, through the heat of re-entry. This is ... hard. They have a strict thermal budget and they have a profile of how many seconds they can afford at what internal temperatures before it's a failure. (I can hear the rising chorus of "Well, how about ..." - I asked Steve if they'd considered docking with the Space Station on the return trip, for example, instead of re-entry. He gave me a dirty look. Yes, they've thought about the options.)

This is risky, and successful missions are apparently all about retiring risk. The way they are reducing their risk profile is by cloning as much of OSIRIS-Rex as possible, and going to a well-understood comet. The launch, the probe, the sampling technique - just like what's happening on Bennu. The comet - 67P/Churyumov-Gerasimenko, already mapped in detail by the Rosetta mission. The refrigeration, the landing, the retrieval - very Mission-Impossible. After it's done, Tom Cruise will be in the movie version.

Meanwhile, though, the two teams have sent in their proposals, and they're waiting to find out who will win the coin toss. There's always the more unpleasant option, given the state of our government, that it'll be neither. But hopefully one or the other gets to fly.

So - go OSIRIS-Rex! And go CAESAR! (Or go Dragonfly!)
posted by RedOrGreen at 10:11 AM on January 28, 2019 [12 favorites]

And go CAESAR!

Given that the mission will end with a sample of cometary ice literally falling from the sky, I feel like "Hail, CAESAR!" is a doubly missed opportunity here.
posted by The Tensor at 3:51 PM on January 28, 2019 [2 favorites]

> Given that the mission will end with a sample of cometary ice literally falling from the sky, I feel like "Hail, CAESAR!" is a doubly missed opportunity here.

Ahhhhhhhhhhhhhhhhh.... :-(

When the mission is approved and there's a post about it, I'll race you to this groaner.
posted by RedOrGreen at 8:17 AM on January 29, 2019

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