NASA OSIRIS-REx Will Sample Return from Asteroid and Other Asteroid News

by

NASA OSIRIS-REx Will Sample Return from an Asteroid

On the afternoon of December 31, NASA OSIRIS-REx entered orbit around asteroid Bennu. About 70 million miles away from Earth, Bennu broke the record for becoming the smallest object in space to have a human-made spacecraft in its orbit.

The NASA OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission is designed to return a sample of material from near-Earth carbonaceous asteroid Bennu. The primary scientific objectives are to: (1) return and analyze a sample (at least 60 g, with a capability of up to 2 kg) of pristine asteroid regolith; (2) map the global properties, chemistry, and mineralogy; (3) document the texture, morphology, volatile chemistry, and spectral properties of the sample site; (4) measure the orbit deviation caused by non-gravitational forces (the Yarkovsky effect); and, (5) characterize the integrated global properties of the asteroid for comparison with ground-based observations. OSIRIS-REx launched on 08 September 2016 at 23:05 UT. It will sample the asteroid in July 2020 and return the sample to Earth in September 2023.

Japan Hayabusa2 Asteroid Rovers

Japan’s Space Agency has sent a mission to an asteroid. Japan’s asteroid mission Hayabusa2 has successfully dropped the first two rovers to the surface of its target space rock Ryugu. Hayabusa2 dropped to a lowest altitude of just 55 meters from the surface and released twin rovers, called MINERVA-II 1A and 1B.

Cameras on the hexagonal rovers will use rotating motors to hop across the surface, each jump lasting some 15 minutes owing to the body’s low gravity.

Hayabusa had left the asteroid and has now returned to it.

This week, Hayabusa2 returned perfectly from solar conjunction to hover back at the home position at 20km from the asteroid. Although this situation was similar to when we approached the asteroid in June, it was a tense operation as there was no room for mistakes. However, the spacecraft was able to return to its orbit exactly as planned. New Year’s Eve on the 31st December was the last operation of the year. The distance to the asteroid could be measured once again with LIDAR and we returned to normal operations without any problems. The beginning of the New Year is a holiday in Japan, but full-scale operations will begin with adjustments for the 2019 touchdown operation.

To guarantee the safety of the mission during the period of solar conjunction, the spacecraft was inserted into a “conjunction trajectory” last week on 2018.11.23. Hayabusa2 will reach its maximum distance of 110km from Ryugu on 2018.12.11 and return to the home position at an altitude of 20km on 2018.12.29

Japan’s Hayabusa mission has an english website.

Luxembourg Talked About Being a Space Mining Hub

The country of Luxembourg has stated they want to become a hub for space mining.

In 2017, Kleos Space, 100% owned by UK-based Magna Parva, is one of dozens of firms to have either settled in the tiny country or signed cooperation agreements with the government since it launched its program to promote the mining of asteroids for minerals last year. Kleos Space will collaborate with EmTroniX, a Luxembourg-based electronics developer, and with the country’s Institute of Science and Technology (LIST), to speed up development of in-space manufacturing technology.

Deep Space Industries and Luxembourg were jointly developing Prospector-X, a small and experimental spacecraft that test technologies for prospecting and mining near Earth asteroids after 2020.

Private Industry Asteroid Mining Problems

Bradford Space, a U.S.-owned space systems manufacturer with locations in the Netherlands and Sweden, has acquired control of Deep Space Industries (aka DSI). DSI will become Bradford’s first substantial U.S. presence, providing an outlet and location for activities in the U.S. space market.

Bradford Space has been part of 119 launches and has 1920 products in space. Bradford is a high-tech developer and manufacturer of satellite control sub-systems and components. They focus on focus on off-the-shelf solutions for satellite and space needs. Bradford has about 75 employees.

In 2012, DSI was started with the goal of mining asteroids. DSI has more recently become known for its production of the Comet™ water-based electrothermal propulsion systems. Four Comet systems are currently on orbit on spacecraft operated by Capella Space and HawkEye 360. Other customers of DSI include LeoStella, a joint venture of Spaceflight and Thales Alenia Space, and the Space Flight Laboratory (SFL), a satellite development group inside the University of Toronto.

The addition of the Comet product line is seen as critical to Bradford’s development as a world-leading supplier of non-toxic space propulsion systems and will be a complement to the Bradford ECAPS ‘green’ propulsion systems. ECAPS propulsion systems are already found on fifteen orbiting spacecraft with more planned for launch in 2019, said Bradford & ECAPS Managing director Patrick van Put. ECAPS propulsion systems were found on three spacecraft on the recently launched Spaceflight SSO-A mission, alongside four spacecraft equipped with DSI Comet systems.

Status of Space Mining

Transastra is a company working on optical mining of asteroids.

The other main asteroid mining company was Planetary Resources. A blockchain software technology company called ConsenSys bought Planetary Resources. ConsenSys has about 900 employees. In December, 2018, ConsenSys restructured and laid off 13% of its staff.

Moon Express has been targeting mining the moon. Moon Express should be getting some money from NASA for commercial lunar payloads.

July 2018, Moon Express was unable to make payroll on several occasions and laid off nine employees. The employees did not receive back-pay until October 2018, four months later. In October 2018, Moon Express signed several collaboration agreements with the Canadian Space Agency (CSA) and a number of Canadian aerospace companies.

On November 29, 2018 Moon Express was awarded a Commercial Lunar Payload Services contract by NASA, which makes it eligible to bid on delivering science and technology payloads to the Moon for NASA.

Aten Engineering provides technical solutions in the areas of detection, discovery, follow-up and characterization of Near Earth Asteroids, with the goal of enabling in-space resource extraction and utilization to pave the way for Human exploration of the Solar System.

Offworld is a company with offices in Pasadena and Luxembourg. They want to send small robots into space and mine asteroids.

Spacefab is another company that is talking about asteroid mining.

11 thoughts on “NASA OSIRIS-REx Will Sample Return from Asteroid and Other Asteroid News”

  1. Mat… Most sub kilometer asteroids due to their rotation accumulate rubble and space debris around their equator as a net goes down the pull from different directions would most likely. A. Cause a snag on one or more of the lines causing it to break. A lot of asteroid to hold back. Or B. The movement across would cause a debris storm across the asteroid potentially destroying everything. Noose and probe is one and one. If your geostationary with asteroid and noose around as you pull tight, probe is away from most potential micro meteorites that may fly around from such an interaction with asteroid.

  2. Small math error in “net diameter is 3 times the asteroid diameter, so ~10 times the surface area”, but the point stands.

    If it’s 3 times the diameter, it’s ~10 times the cross-section area, and only ~2.5 times the surface area. So divide the net volume and mass results by 4.

    Also, lots of rounding everywhere, so the numbers are very rough.

    P.S. Back to matching rotation, you’d need to account for conservation of angular momentum. The more the net opens up, the more it’ll spin down. That might be a good way to match fast spinning asteroids: start wide, give it a spin, then reel in the tethers to spin up.

  3. For a ~10 m diameter asteroid, the volume is ~500 m^3, and the surface area is ~300 m^2 (assuming a roughly spherical shape). Suppose the net diameter is 3 times the asteroid diameter, so ~10 times the surface area, so 3000 m^2. But being a net, the actual area is maybe 1/10th of that (account for holes), so back to 300 m^2. Let’s say on a WAG, the net thickness is ~5 cm, and it’s attached to 4 thethers that are each 100 m long, and ~10 cm thick.

    So the net volume is 300 m^2 * 0.05 m = 15 m^3. And the tethers are 4 * 100 m * (0.1 m)^2 = 4 m^3. Total 19 m^3, let’s say 20.

    You can see that the volume is much smaller than the asteroid. But kevlar density is ~1.5 g/cc; carbonaceous chrondites are ~3-4 g/cc; metallic asteroids are twice that (source: http://meteorites.wustl.edu/id/density.htm ). So the asteroid would weigh ~50-100 times more than the net + tethers.

    If we made the net diameter 100 m (10 times the asteroid), and the tethers 1 km long, their total volume would be 90 m^3, and the asteroid would still weigh ~10-20 times more.

    The net mass scales roughly quadratically with the size of the asteroid it’s intended for (not exactly, since you may need a thicker net), the tethers mass scales roughly linearly, but the asteroid mass scales cubically. So for larger asteroids, the difference is larger. But the load on the net also scales cubically, so there’s a limit to the size of the asteroid you can capture this way. There’s probably a sweet-spot somewhere in between.

  4. You’re correct that the net dynamics are complex. It’ll likely require a lot of simulations and testing to get right. As a rule of thumb, you want to match the rotation of the asteroid as much as possible before attempting to capture it. You’d probably want to get into a highly eccentric orbit around the asteroid, with the long axis of the orbit parallel to the asteroid’s axis of rotation. Then on one of the approaches, adjust course to effectively ram the asteroid, match the rotation, and split open so that the sub-probes pass on opposite sides. Asteroid gravity is very weak, so the relative velocity would be small. I don’t expect a lot of bounce-back.

    Where you’re definitely wrong, is the mass ratio. The net only needs to cover the surface area of the asteroid (times some fudge factor), and is made of lighter material. You’d make it from some high strength-to-weight fiber like kevlar, not steel. It may be attached to long tethers to give the probes enough maneuvering room, but that too is a relatively small amount of material (calculations separately – characters limit). Whereas the asteroid’s mass comes from its entire volume.

    I agree that a single tether would be lighter, if one could make it work. But as I’ve mentioned in my previous post, the selection of suitable asteroids would be smaller.

    The net idea isn’t mine, btw. It’s been tossed around many times before, likely in slightly different forms. Some proposals even talk about bags instead of nets.

  5. Mat… Good sized craters on an asteroid should mean that they should be solid enough. If they can withstand an impact and not bust apart i should hope they could handle a cable around them. Definately would choose slow rotating asteroid. Net and extra probes would work. Lots of extra material needed. If you can rap around once why not. Less material to take. The net would have to be massive as compared to the asteroid even if was only lets say five cables. If any part of the net hits the asteroid before the probes are around i would imagine it could create a ripple and bounce back effect affecting throughout. In some cases the more you thrust the more the net would bounce away. If you net polar cables would twist up. If you net from equator polar cables would twist down and in causing the one underneath and in rotation to bunch up. Could snap and brake everything.

  7. Osiris-Rex doesn’t have a lander. It has a spring-loaded collection arm that will blow nitrogen across the contact surface, into a collection chamber. The momentum of the spacecraft will keep the arm in contact for the second or two needed to do the operation. It will *bounce* off the asteroid like a pogo stick.

  8. For a more spherical one you could use a net. The probe could split to 3-4 mini-probes, each holding one corner of the net. Fly past the asteroid on opposite sides, then dock back together on the other end. Net closed, asteroid captured.

    Even with peanut-shaped asteroids, we don’t know if they’re a single chunk, or a loose rubble pile. And if single, how strong? Then there’s the issue of spin making things more complicated. A net can work in all of these cases. Though it may still have trouble if the spin is too fast.

    I’ve said this before, but I’ll repeat: you should go study engineering, at least from online courses. Your ideas will be much better if you do.

    Btw, how old are you?

  9. Mat… I’d imagine the asteroids to look for for mining or to study and explore ideally would be elongated irregular shaped asteroids with good craters. As the craft goes around the asteroid low enough to could let go a cable. Long bar arm and grabhook grabs cable once around. Tightens the noose and tethers down to the asteroid. Could then follow around the asteroid studying different areas if needed. Round asteroid would be difficult to lasso. Like trying to rope a bowling ball. Find one like a dog bone. Eros. And it would be easier as the noose wouldn’t slip off either side easily.

  10. Its kind of interesting to consider the dynamics of Bennu.

    It is about 0.492 km in diameter, has a mean density of about 1250 kg/m³ and a surface gravity of approximately 10 micro Gs. A few napkin calculations show it has an ESCAPE velocity of only 0.1 m/s!

    Think about that! 

    The escape velocity is so low that if (somehow) an athlete in a space suit were simply to jump straight up, she’d completely and forever escape the gravitational pull of Bennu. The lander, when it eventually lands, will touch down at a few millimeters per second.  Like watching grass grow!

    The idea of building a big net-like structure around such a thing, and chipping off chunks makes a lot of sense. We’d certainly not have to chip very hard… again, as improbable as it might really be, imagining a robot that drills “for its feet and traction” into the surface a bit, then using a lever arm, just lobs bits of Bennu toward the “net” outside makes sense. Low energy, etc. 

    With such a profoundly low self-gravitational pull, the article’s conclusion that Bennu’s stuff is one big aggregation, barely “glued” together is perhaps both possible, and at the same time not likely: the “carbonaceous” character of its makeup also has a lot of tar-like binding chemicals. Indeed: carbonaceous chondrites are not hard (like rocks) but tough (like chunks of pavement asphalt). 

    Just saying,
    GoatGuy

  11. Mat… Thanx so much for these articles about asteroids. They’re some of my favorites. Going to look up some of the links. Can’t wait until actual space mining starts. Sure to be some interesting stories along the way.

Comments are closed.