Starship Asterisk*

http://www.planetary.org/blogs/jason-davis/minerva-ii1-successful-landing.html wrote:

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This image was captured by MINERVA-II1 Rover-1A on September 22 at around 2:44 UTC. The image was captured mid-hop after a successful landing.









This is an artist’s illustration of the three hopping rovers on Ryuku’s surface with MINERVA-II1A and MINERVA-II1B (left and center), and MINERVA-II2 (right) exploring the surface of the asteroid Ryugu. JAXA

http://www.hayabusa2.jaxa.jp/en/topics/20180731e/index.html wrote:

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A stereoscopic image of Ryugu at high resolution

<<The article posted on July 25, 2018 introduced an image captured when Hayabusa2 descended towards asteroid Ryugu, reaching an altitude of just 6km above the surface. At this time, we also took photographs in which the viewing angle towards the asteroid gradually changed as Ryugu rotated. Using the previously published image and a second image from a slightly different angle (see the referlence at the end of this page), we created a composite frame where the two photographs are superimposed in red and blue. If you view this image with red-blue stereoscopic glasses (right eye should be blue, left eye is red), you can see this high resolution image of the asteroid in three-dimensions and explore the shape and topography of this small world.>>

A red and blue stereoscopic image of Ryugu, prepared from the images taken by the Optical Navigation Camera - Telescopic (ONC-T) at an altitude of 6km. The images were taken on July 20, 2018.

Image credit：JAXA, University of Aizu, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University and AIST.

neufer wrote: ↑Sun Jul 01, 2018 1:06 am

Chris Peterson wrote: ↑Sat Jun 30, 2018 10:58 pm

rstevenson wrote: ↑Sat Jun 30, 2018 2:34 pm
Try to imagine getting planning permission (from whom?) to alter the orbit of an asteroid such that, in a few years time, it gently comes up on the Earth from behind and can then be nudged into a stable orbit for nearby resource extraction. Imagine the Chicken Little reaction from luddites everywhere. Might be better to extract the useful material out there in the distance, and shoot smallish chunks of it towards the Earth/Moon for capture. Makes a smaller Kaboom! if you miscalculate.

I am no Luddite, but I would strenuously oppose the development and use of technology to move around space rocks!

• Isn't that a direct T. Rex quote

Chris Peterson wrote: ↑Sat Jun 30, 2018 10:58 pm

rstevenson wrote: ↑Sat Jun 30, 2018 2:34 pm
Try to imagine getting planning permission (from whom?) to alter the orbit of an asteroid such that, in a few years time, it gently comes up on the Earth from behind and can then be nudged into a stable orbit for nearby resource extraction. Imagine the Chicken Little reaction from luddites everywhere. Might be better to extract the useful material out there in the distance, and shoot smallish chunks of it towards the Earth/Moon for capture. Makes a smaller Kaboom! if you miscalculate.

I am no Luddite, but I would strenuously oppose the development and use of technology to move around space rocks!

• Isn't that a direct T. Rex quote

rstevenson wrote: ↑Sat Jun 30, 2018 2:34 pm

BDanielMayfield wrote: ↑Tue Jun 26, 2018 9:57 pm This Earth crossing asteroid is being eyed for potential mining operations:

As of May 2018, according to the Asterank website, operated by Planetary Resources, the current value of Ryugu for mining purposes is speculated to be US$82.76 billion, and the chemical composition of the asteroid is claimed to be of nickel, iron, cobalt, water, nitrogen, hydrogen and ammonia.

Try to imagine getting planning permission (from whom?) to alter the orbit of an asteroid such that, in a few years time, it gently comes up on the Earth from behind and can then be nudged into a stable orbit for nearby resource extraction. Imagine the Chicken Little reaction from luddites everywhere. Might be better to extract the useful material out there in the distance, and shoot smallish chunks of it towards the Earth/Moon for capture. Makes a smaller Kaboom! if you miscalculate.

Rob

BDanielMayfield wrote: ↑Tue Jun 26, 2018 9:57 pm This Earth crossing asteroid is being eyed for potential mining operations:

As of May 2018, according to the Asterank website, operated by Planetary Resources, the current value of Ryugu for mining purposes is speculated to be US$82.76 billion, and the chemical composition of the asteroid is claimed to be of nickel, iron, cobalt, water, nitrogen, hydrogen and ammonia.

BDanielMayfield wrote: ↑Sat Jun 30, 2018 11:27 am
The real usefulness of such a pile of materials would be out in space though, where it costs a great deal to launch anything into orbit.

Boody wrote: ↑Thu Jun 28, 2018 2:11 pm

BDanielMayfield wrote: ↑Tue Jun 26, 2018 9:57 pm This Earth crossing asteroid is being eyed for potential mining operations:

As of May 2018, according to the Asterank website, operated by Planetary Resources, the current value of Ryugu for mining purposes is speculated to be US$82.76 billion, and the chemical composition of the asteroid is claimed to be of nickel, iron, cobalt, water, nitrogen, hydrogen and ammonia.

You can imagine what wide scale asteroid mining will do to the metals markets. 16 Psyche is the prize here, it's a big chunk of iron and nickel and likely lots of other good stuff. Gold, silver, platinum, etc. prices would drop like crazy. Countries with gold stockpiles will find them comparatively worthless. I don't think any country would even try it considering these repercussions, or would at least divest well in advance.

Hop Happy wrote: ↑Fri Jun 29, 2018 4:34 pm

neufer wrote: ↑Thu Jun 28, 2018 6:53 pm

Hop Happy wrote: ↑Thu Jun 28, 2018 5:18 pm
How do the hoppers hop?

Thanks Art. The JAXA website said the MASCOT can hop too, but only once. I assume that means it's not using reaction wheels for its motion or only has enough power to use them once? Anyway, it's a very clever means of moving about, especially in micro-gravity.

neufer wrote: ↑Thu Jun 28, 2018 6:53 pm

Click to play embedded YouTube video.

Hop Happy wrote: ↑Thu Jun 28, 2018 5:18 pm

APOD Robot wrote:
Hayabusa2 is carrying an armada of separable probes, including two impactors, four small close-proximity hoverers, three small surface hoppers, and the Mobile Asteroid Surface Scout (MASCOT) which will land, study, and move around on Ryugu's surface.

How do the hoppers hop?

Hop Happy wrote: ↑Thu Jun 28, 2018 5:18 pm

APOD Robot wrote:
Hayabusa2 is carrying an armada of separable probes, including two impactors, four small close-proximity hoverers, three small surface hoppers, and the Mobile Asteroid Surface Scout (MASCOT) which will land, study, and move around on Ryugu's surface.

How do the hoppers hop?

APOD Robot wrote: ↑Mon Jun 25, 2018 4:11 amAmbitious Hayabusa2 is carrying an armada of separable probes, including two impactors, four small close-proximity hoverers, three small surface hoppers, and the Mobile Asteroid Surface Scout (MASCOT) which will land, study, and move around on Ryugu's surface.

Boody wrote: ↑Thu Jun 28, 2018 2:11 pm

BDanielMayfield wrote: ↑Tue Jun 26, 2018 9:57 pm This Earth crossing asteroid is being eyed for potential mining operations:

As of May 2018, according to the Asterank website, operated by Planetary Resources, the current value of Ryugu for mining purposes is speculated to be US$82.76 billion, and the chemical composition of the asteroid is claimed to be of nickel, iron, cobalt, water, nitrogen, hydrogen and ammonia.

You can imagine what wide scale asteroid mining will do to the metals markets. 16 Psyche is the prize here, it's a big chunk of iron and nickel and likely lots of other good stuff. Gold, silver, platinum, etc. prices would drop like crazy. Countries with gold stockpiles will find them comparatively worthless. I don't think any country would even try it considering these repercussions, or would at least divest well in advance.

BDanielMayfield wrote: ↑Tue Jun 26, 2018 9:57 pm This Earth crossing asteroid is being eyed for potential mining operations:

As of May 2018, according to the Asterank website, operated by Planetary Resources, the current value of Ryugu for mining purposes is speculated to be US$82.76 billion, and the chemical composition of the asteroid is claimed to be of nickel, iron, cobalt, water, nitrogen, hydrogen and ammonia.

http://www.planetary.org/blogs/emily-lakdawalla/2018/0627-hayabusa2-arrived-at-ryugu.html wrote: Itokawa and Ryugu comparison: Emily Lakdawalla, The Planetary Society.

The two target asteroids of Hayabusa and Hayabusa2, compared. The comparison is based on less-than-precise information on the scales of the two images; it may be updated with another version once better scale information is available. Images: JAXA, University of Tokyo, Koichi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu and AIST.

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JAXA confirmed Hayabusa2, JAXA's asteroid explorer rendezvoused with Ryugu, the target asteroid.

On June 27, 2018, JAXA operated Hayabusa2 chemical propulsion thrusters for the spacecraft's orbit control.

The confirmation of the Hayabusa2 rendezvous made at 9:35 a.m. (Japan Standard Time, JST) is based on the following data analyses;

• The thruster operation of Hayabusa2 occurred nominally
• The distance between Hayabusa2 and Ryugu is approximately 20 kilometers
• Hayabusa2 is able to maintain a constant distance to asteroid Ryugu
• The status of Hayabusa2 is normal

From this point, we are planning to conduct exploratory activities in the vicinity of the asteroid, including scientific observation of asteroid Ryugu and surveying the asteroid for sample collection.

As of May 2018, according to the Asterank website, operated by Planetary Resources, the current value of Ryugu for mining purposes is speculated to be US$82.76 billion, and the chemical composition of the asteroid is claimed to be of nickel, iron, cobalt, water, nitrogen, hydrogen and ammonia.

neufer wrote: ↑Tue Jun 26, 2018 4:53 pm

BDanielMayfield wrote: ↑Tue Jun 26, 2018 2:41 pm
Is the axis of rotation of Ryugu such that the equator and poles line up with its rather biconic shape?

That seems clear from the APOD's dozen images.

BDanielMayfield wrote: ↑Tue Jun 26, 2018 2:41 pm
Is the axis of rotation of Ryugu such that the equator and poles line up with its rather biconic shape?

neufer wrote: ↑Mon Jun 25, 2018 4:56 pm

Image of Ryugu, taken June 24, 2018

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donalgary wrote:
All pictures show view at nearly the same angle.

Is that by by careful choice of pictures or because asteroid has very low angular momentum?

There are 4 groups of 3 pictures shown at nearly the same angle.

The rotation period is ~ 7 hours 38 minutes.

https://en.wikipedia.org/wiki/Accretion_(astrophysics)#Accretion_of_asteroids wrote:

Chondrules in a chondrite meteorite. A millimeter scale is shown.

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<<Meteorites contain a record of accretion and impacts during all stages of asteroid origin and evolution; however, the mechanism of asteroid accretion and growth is not well understood. Evidence suggests the main growth of asteroids can result from gas-assisted accretion of chondrules, which are millimeter-sized spherules that form as molten (or partially molten) droplets in space before being accreted to their parent asteroids. In the inner Solar System, chondrules appear to have been crucial for initiating accretion. The tiny mass of asteroids may be partly due to inefficient chondrule formation beyond 2 AU, or less-efficient delivery of chondrules from near the protostar. Also, impacts controlled the formation and destruction of asteroids, and are thought to be a major factor in their geological evolution.>>

https://en.wikipedia.org/wiki/Bicone wrote:
<<A bicone or dicone (bi- comes from Latin, di- from Greek) is the three-dimensional surface of revolution of a rhombus around one of its axes of symmetry. Equivalently, a bicone is the surface created by joining two congruent right circular cones base-to-base.>>

https://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System#Formation_of_the_planets wrote:

A bicone or dicone

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<<The various planets are thought to have formed from the solar nebula, the disc-shaped cloud of gas and dust left over from the Sun's formation. The currently accepted method by which the planets formed is accretion, in which the planets began as dust grains in orbit around the central protostar. Through direct contact, these grains formed into clumps up to 200 metres in diameter, which in turn collided to form larger bodies (planetesimals) of ~10 kilometres in size. These gradually increased through further collisions, growing at the rate of centimetres per year over the course of the next few million years.

A planetesimal is a solid object arising during the accumulation of planets whose internal strength is dominated by self-gravity and whose orbital dynamics is not significantly affected by gas drag. This corresponds to objects larger than approximately 1 km in the solar nebula.

Bodies large enough not only to keep together by gravitation but to change the path of approaching rocks over distances of several radii start to grow faster. These bodies, larger than 100 km to 1000 km, are called embryos or protoplanets.>>

MountainJim wrote:
Makes me wonder why we haven't landed telescopes/cameras/instruments on asteroids and let them travel to the far end of the solar system and send back images/data?