NASA Drops Spacecraft Into Orbit Around Potentially Hazardous Asteroid Bennu (cnet.com) 50
NASA's asteroid-chasing Osiris-Rex spacecraft has been placed in an orbit around Bennu, an asteroid that drifts through the solar system's asteroid belt between Earth and Mars. "By inserting itself into orbit around Bennu, Osiris-Rex will survey the asteroid from a distance of only about 1 mile (1.75 kilometers) from its center," reports CNET. "Bennu's small size creates an incredibly tiny gravitational force, so maintaining that orbit will require lots of little adjustments, made by NASA and its collaborating organizations." From the report: "The gravity of Bennu is so small, forces like solar radiation and thermal pressure from Bennu's surface become much more relevant and can push the spacecraft around in its orbit much more than if it were orbiting around Earth or Mars, where gravity is by far the most dominant force," said Dan Wibben, maneuver and trajectory design lead. NASA also released a GIF of the various surveys Osiris-Rex carried out after arriving at Bennu in early December The series of images, captured between Nov. 30 and Dec. 31, helped the team more accurately determine Bennu's mass, which ensured that the orbital insertion would proceed smoothly.
The orbital period, lasting until mid-February, is expected to provide additional details about Bennu's gravity, orientation and spin, along with a better understanding of its mass. All those observations should lead to completing one of the chief objectives for Osiris-Rex: retrieve a sample from Bennu's surface and fly it back to Earth. In 2020, the spacecraft will extend a specially designed arm, called Tagsam, for a brief high-five with the asteroid. The arm will blow nitrogen gas onto the surface of Bennu, kicking up handfuls of dirt, which the spacecraft will fly back to Earth in 2023.
The orbital period, lasting until mid-February, is expected to provide additional details about Bennu's gravity, orientation and spin, along with a better understanding of its mass. All those observations should lead to completing one of the chief objectives for Osiris-Rex: retrieve a sample from Bennu's surface and fly it back to Earth. In 2020, the spacecraft will extend a specially designed arm, called Tagsam, for a brief high-five with the asteroid. The arm will blow nitrogen gas onto the surface of Bennu, kicking up handfuls of dirt, which the spacecraft will fly back to Earth in 2023.
Re: Hey China (Score:2)
Don't worry, I'm sure boulat will drop by any minute to chinsplain to us why this is insignificant in the face of the recent Chinese surpassing of the US.
Re: (Score:2)
The race is on! Do you think he'll beat AmiMoJo?
Re: Hey China (Score:2)
Depends whether one of the scientists is wearing a tacky shirt or not.
Re: Journalism 101 (Score:1)
It has not been measured perfectly. Indirectly they measured mass so as to determine what the proper orbits could be, but as far as other measurements, the asteroid is not spherical and for different purposes you might measure surface area, volume, equatorial distance in different directions, etc. Amusingly, Bennu was originally charted back when the EU was switching from imperial units to metric and there are some measurements for which NASA is unsure of the units. I would guess NASA will try to standardiz
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Huh? Europe (except the UK) has been using metric units for a long time, certainly long before the EU even existed, and long before Bennu was discovered in 1999.
Re: Journalism 101 (Score:5, Interesting)
Most of Europe never used any imperial system/unit anyway. Unless you want to call "having a foot or a mile" imperial. Every foot, mile, every "elbow" every "thumb" as in inch, every pound or ounce had its own size, and no, the correlation between one and the other was not based on 12 or 16, but was most of the time random. While weights usually stayed constant over time, that means a pound was a pound was a pound, distances did not. When the old "king" died, the new one changed feet and thumb and elbow according to his own body size. Miles were arbitrary set, sometimes rulers thought the longer the better (going far away from the roman 1000 paces metric - a pace are two steps, for you americans you mix up paces with steps). It was a kind of prestige object, because they converted how many miles a soldier could work in an hour (about 3) back and force into how fast their fastest elite troops were. So if they managed to do 1800 paces in one hour the mile would be as long as that ... often that number was simply invented. Other tricks were, to simply use two hours of walking instead of one, so became the "Baadische Meile" the longest mile in german history (Mile of the Margraviate of Baaden) https://en.wikipedia.org/wiki/... [wikipedia.org]. Albeit in this case they did not cheat, besides using 2h as base and interestingly the Margrave Carl Friedrich himself with his entourage walked in 2h the distance of 8.88889 km
Germany probably topped it by having about 50 different definitions for everything.
Anyway, the slow unification and the introduction of railways etc. forced them to unify the systems, it is a bit complicate to plan a railway trip from Warschau to Madrid if you have to go through dozens of borders where each principal has defined his one system of length and his own local time zone.
Re: Journalism 101 (Score:4, Interesting)
"American railroads maintained many different time zones during the late 1800s. Each train station set its own clock making it difficult to coordinate train schedules and confusing passengers. Time calculation became a serious problem for people traveling by train (sometimes hundreds of miles in a day), according to the Library of Congress. Every city in the United States used a different time standard, so there were more than 300 local sun-times to choose from. Railroad managers tried to address the problem by establishing 100 railroad time zones, but this was only a partial solution to the problem.
Operators of the new railroad lines needed a new time plan that would offer a uniform train schedule for departures and arrivals. Four standard time zones for the continental United States were introduced on November 18, 1883."
Re: (Score:2)
A little buzzed and apparently failed to read the final sentence in it's entirety as upon re-reading your comment I see you made note of that.
Fuck it, it's the weekend, party on....
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We look upon that with horror today, but it just didn't matter back then because they didn't have standardized measuring tools. The machines necessary to mass produce standardized measuring tools didn't come about until the Industrial Revolution in the 1800s. So the king could mess with the units all he wanted. The people would just ignore it and build using whatever measuring tools they had on hand. A
Re: Journalism 101 (Score:1)
Also leading with "potentially hazardous" in the headline and then not mentioning it at all in the summary.
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"Bennu's small size"
But Chinese frequently state that small size does not matter.
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My girlfriend also said that a small dick is no problem.
OK... well... still... I'd prefer she had none at all.
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Hopefully (Score:2)
They'll be able to use the microgravity "pull" exerted by the spacecraft to gradually steer the object clear of Earth
Strat
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Failing that a bunch of herpin' derpin' oilmen will destroy it - but only after them there fancy-pants book-learned so-called "scientists" totally fail it.
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If not, they could try to shoot depleted uranium slugs at it via a giant railgun.
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It would be kind of funny if the tiny effect of the nearby probe would create a course correction that resulted in a hit rather than a near miss near the end of the 22nd century. OK, maybe "funny" is not quite the right word...
Sunday best (Score:2)
I thought the asteroid belt was between Mars and Jupiter?
Re:Sunday best (Score:5, Informative)
NASA not shutdown? (Score:2)
I thought that the US government was shutdown right now. Why is NASA still working?
Although, I could imagine that the folks working on this project would continue, even if they didn't get paid for it.
Re: (Score:3)
From Space.com
" Most NASA personnel will be furloughed until such an agreement is reached, agency officials explained recently in a shutdown FAQ. "Most" is something of an understatement, in fact; about 95 percent of NASA employees won't be able to go to work.
But don't panic: There are "excepted" employees, such as the folks responsible for keeping NASA people and property safe. And "property" includes currently operational spacecraft, as well as the dat
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old (Score:2)
Orbital Forces (Score:1)
The acceleration experienced by Osiris-Rex while in orbit = G m / r_oribit^2
= (6*10^-11)*(6*10^10)/(1700^2) = 1*10^-6 m/sec^2
The force exerted on by Bennu on Osiris-Rex (assuming mass of 880 kg) while in orbit = G m_B m_OR / r_orbit^2
= 880*(6*10^-11)*(6*10^10)/(1700^2) = 0.001 Newtons.
Tidal force of sun on Osiris-Rex = G m_OR m_Sun r_orbit / (1 AU)^3 = 6*10^-11*880*2*10^30*1700/(150*10^9)^3
= 50 nano-Newtons.
Light pressure from sun = A_OR S_Sun/c = A_OR*P = 6*4.5^10^-6 = 30 micro-Newtons.
Thermal Radiatio
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I think the thermal pressure calculation should not include albedo.
Thermal Radiation Pressure from Bennu = S_B A / c /c = S_Sun *r_B^2 / (4 r_orbit^2) A/c
= S_Sun * pi r_B^2 / (4 pi r_orbit^2) A
= 1300*262^2/(4*1700^2)*6/(3*10^8) = 150 nano-Newtons.
When is NASA going to drop some hydrogen (Score:2)
bombs into volcanoes?
Link to GIF at NASA (Score:1)
Full rotation: https://www.nasa.gov/sites/default/files/styles/full_width/public/thumbnails/image/bennushapemodel.gif
Potentially hazardous to whom? (Score:2)
What a pathetic click bait title. Bennu is only hazardous to the inanimate object circling it.