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Objects about 10 cm and larger can be tracked in low orbit. That means the radar can follow an object long enough to derive orbital elements, allowing reliable predictions of where the object will be later. Objects about 2 mm and larger can be sampled by high-power radars. That means the radar helps build a statistical population based on whatever zips across a fixed beam.

I found a couple of figures (Fig. 1 and Fig. 24) showing the gap between tracking (Space Surveillance Network) and other sampling data sources. Also a recent presentation.

We can track its orbit very well. The unknown is the amount of air resistance it encounters, i.e. how quickly its orbit will degrade. This resistance is highly variable (because the atmosphere expands and contracts e.g. in response to solar activity) and difficult to predict.

A Brown Dwarf is 15 to 75 times the mass of Jupiter.

I was hoping to see inside Uranus.
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OKAY! It's been posted. Sorry folks, you're too late to make the joke now.

I don't know why you think that is a joke. It's called the
Advanced NASA Atmospheric Lithographic Lidar Probe and it was designed to update us about the aerosols in Uranus.

Last I heard they were figuring out just how many instruments they can include to explore Uranus and the rings around it. First the rings and then and deep as they can go for as long as there is battery power remaining to keep all of the instruments going before it is crushed by the pressure of the most concentrated source of methane in the solar system. That's right, there is a lot of methane in Uranus.

If you're laughing now, you can just stop it - you're being juvenile. Exploring Uranus is a serious undertaking that many people are committed to and clever jokes about "hoping to see inside Uranus" are just unsophisticated. We're better than that here.

Would those be non-inert hydrocarbon aerosols?

I was hoping to see inside Uranus. . . . . . . OKAY! It's been posted. Sorry folks, you're too late to make the joke now.

I don't know why you think that is a joke. It's called the Advanced NASA Atmospheric Lithographic Lidar Probe and it was designed to update us about the aerosols in Uranus.

Last I heard they were figuring out just how many instruments they can include to explore Uranus and the rings around it. First the rings and then and deep as they can go for as long as there is battery power remaining to keep all of the instruments going before it is crushed by the pressure of the most concentrated source of methane in the solar system. That's right, there is a lot of methane in Uranus.

If you're laughing now, you can just stop it - you're being juvenile. Exploring Uranus is a serious undertaking that many people are committed to and clever jokes about "hoping to see inside Uranus" are just unsophisticated. We're better than that here.

If things get any worse I might end up going outside.

Man, I went outside last August and it turned out even the SUN was broken!

Although they claimed it was a regularly scheduled patch. Even so!

Well, it has a sufficient energy gradient to shoot out geysers (which have been shown to contain molecular hydrogen and organic molecules), so I'd say so.

This is just nothing more than a bit of paid advertising from IBM.

IBM provided the hardware and software for the avionics on the Space Shuttle . . . programmed in . . . IBM /360 Assembler! They chose that language because it had been around for long enough that NASA figured that all the bugs had been worked out, and the programmers understood the language well enough that it could be used for man-rated systems:

https://history.nasa.gov/compu...

Is it possible that our exploration of space could inadvertently be leaving a trail of life

That's why NASA has gone to great lengths to sterilize spacecraft headed to places like Mars. There's even a planetary protection officer.

I've heard the US signed an international treaty to that effect. Alcohol sterilization, course correction to avoid the rocket's third stage hitting Mars, and spacecraft are not allowed to carry more than 300,000 bacterial spores. I'm sure NASA is doing a fine job, but they ain't the only ones sending stuff to space.

The microbes on the surface of the ISS may or may not come from the atmosphere, but that they stay alive while in space suggests that life could 'go forth and multiply' by those not as concerned about sterilizing as is NASA. Here, there are plenty of candidates. Venture capitalists are launching hundreds of satellites now. Elon Musk launched a potentially un-sterilized car into space the other day, and promises Martian colonies with people, food and microbial-laden poop. China, Japan and India are talking space tourism; still others plan on mining asteroids. At some point in the future that international treaty will be a thing of the past. And life will go on.

https://mars.nasa.gov/mer/technology/is_planetary_protection.html

https://www.salon.com/2018/02/12/why-sending-a-tesla-into-orbit-is-a-slap-in-the-face-to-science/

http://www.businessinsider.com/starman-elon-musk-car-orbit-collision-risk-calculations-2018-2

The second biggest ice sheet, Greenland, seems to be adding mass since it's at a record level. And overall, snow accumulation in the Northern hemisphere is on a decidedly upward trend over the last 30 years.

The GRACE satellites beg to differ. They show Greenland losing ice mass at a rate of about 280 gigatons per year from 2002 to 2016.

Greenland Ice Loss 2002-2016

https://www.nasa.gov/feature/goddard/2017/sea-ice-extent-sinks-to-record-lows-at-both-poles

https://www.nasa.gov/feature/g... ?

Is NASA an okay source, scumbag?

https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses

I didn't know Rush Limbaugh worked for NASA: https://www.nasa.gov/feature/g...

...about climate change and CO2 emissions, a paper published last August (Seroussi et al. 2017) demonstrated that a mantle plume under Western Antartica is heating the region. NASA JPL news release of Helene Seroussi's paper : https://www.jpl.nasa.gov/news/... Full research paper (not paywalled): https://www.researchgate.net/p... Interesting that the Gardner paper in The Cryosphere makes no mention of mantle plumes (a least a quick search for both words turned up zero results). Since both authors are at JPL you would think that Alex Gardener would be aware of Helen Seroussi's 2017 paper and at least mentioned it.

https://www.nasa.gov/feature/g...

So, just 4 years ago NASA published this.
https://www.nasa.gov/content/g...

After a period of unusually high amounts, why would it be surprising to see a regression to the mean?

Discuss

And someone else posted a follow-up NASA paper which comes to a different conclusion.

1 Introduction

The Antarctic ice sheet receives roughly 2000 Gt (â¼ 5.5 mm sea-level equivalent) of precipitation each year with > 90 % of this mass leaving as solid ice discharge to the ocean and the remaining [less than] 10 % leaving in the form of sublimation, wind-driven snow transport, meltwater runoff and basal melt.

2000 Gt gain > 1929 Gt loss. The uncertainty over how much is lost via sublimation and water runoff clouds whether Antarctica has a net gain or loss of ice.

The last study I saw on this (from 2015 based on satellite data) concluded the net effect is Antarctica is gaining ice.

Refuted by the Grace study; https://grace.jpl.nasa.gov/res... "Research based on observations from NASAâ(TM)s twin NASA/German Aerospace Centerâ(TM)s twin Gravity Recovery and Climate Experiment (GRACE) satellites indicates that between 2002 and 2016, Antarctica shed approximately 125 gigatons of ice per year, causing global sea level to rise by 0.35 millimeters per year."

That's cherry picking the region, since NOAA says Antarctica is gaining ice mass overall. You're looking at a tiny area of the continent, and worrying about it. Furthermore, Western Antarctica is also the site of a lot of geothermal activity which could very well be why it is losing ice. But the continent, as a whole, is gaining.

NASA says that Antarctica is gaining ice mass except for the area with the plumes, so...

Yep, them dumb country boys don't make phone apps. They make something stupid like rockets to mars. https://www.nasa.gov/centers/m...

This article is the most poorly worded article I have read in a long time. It was not at all clear what they meant. However, the NASA link is quite clear.

https://www.nasa.gov/feature/new-horizons-captures-record-breaking-images-in-the-kuiper-belt

It is not the farthest picture from earth. It was not taken from earth, or even near earth. It is not the picture itself they are talking about. It is the space probe that took it. New Horizons was the furthest from Earth of any space probe that has taken a picture (any picture).

Voyager 1 was 3.75 billion miles away from Earth when it took a picture. It just so happens it was a picture of Earth.
New Horizons was 3.79 billion miles away from Earth when it took a picture. (That is the record they are talking about).

The Engadget page linked has 9 trackers and 21 scripts according to my sources. Slashdot often sends us to Engadget. Ever wonder why? The NASA page has the same information without the crap and far fewer trackers and scripts. But maybe NASA doesn't kick back anything to Slashdot. I don't know but I'm really getting tired of these crappy links to second class news sources. Try this site: https://www.nasa.gov/feature/n...

Sea level rise depends on location and you're mixing up two very different things. An average rise of 3 inches is different than a vulnerable location getting a 2 feet increase. The first (3 inch average) is a verifiable fact. The second is a prediction by models for what will happen at a certain location, and is very likely to come true.

The average number is 7.6 inches of rise over the next 75 years[1]. Which still should give you pause, but should be less surprising given that the 3x difference in duration didn't lead to a greater than 3x change in sea levels. Nice linear progression that shouldn't make your head spin. Of course these are very conservative estimates and don't take into account acceleration due to released ice methane, etc.

25 years of data? Why not 26 years of data?

Because the earliest data set came from the TOPEX/Poseidon satellite altimetry mission, which launched in 1992, and the paper was received for review in 2017. 2017-1996 = 25 years.

No, because 25 years of data means this is Science Fact! Don't be a denier! This surely proves it once and for all!

25 years of data? Why not 26 years of data?

Because the earliest data set came from the TOPEX/Poseidon satellite altimetry mission, which launched in 1992, and the paper was received for review in 2017. 2017-1996 = 25 years.

  Paper under discussion: http://www.pnas.org/content/ea...

The scientists were unable to use satellite data taken before the satellite launched because that data does not exist.

Going by NASA's own data, sea level has grown a massive 29 centimeters in the last 150 years, and at a pretty steady clip. Let's assume this is accelerating, although the last 150 years have seen quite a massive amount of forest loss/burning and fossil fuel use. What exactly is the coming disaster here? I know people claiming NYC will be underwater and labelling those who disagree as deniers.

None of the climate change data points to anything close to unmanageable disaster. People can easily engineer solutions to deal with such slow change.

Main reason for the great expense (of putting up the ISS and maintaining it) was that the govt spent $1 billion - $2 billion (depending on who you ask) per Shuttle launch to get up there.

The Shuttle hasn't been involved since 2011 and the ISS costs somewhere around $3 Billion/year according to NASA. According to NASA launch and transport costs account for about 34% of ISS operating costs. Systems operation and maintenance accounts for about 43% of costs.

Falcon Heavy costs less than 1/10th of that now, perhaps 1/100th of that in the near future, and carries more payload per launch to boot.

They don't need Falcon Heavy to support the ISS at this point. Falcon 9 is already supply resupply missions.

When the times nears that ISS needs to be de-orbited or given costly maintenance, it might be sensible to just give it away to SpaceX in return for promising to keep it in orbit and operational for a certain number of years.

Give me a credible reason why SpaceX would be interested. Their only interest in the ISS is in providing transport services to and from. There is no obvious profit in actually owning the station to them.
 

https://www.nasa.gov/centers/a...

Yes, the atmospheric pressure is lower, but it's also much denser which offsets the lower pressure considerably. Wind power, while not as effective as they would be on Earth, is still a viable option on Mars.
=Smidge=

It wasn't quite that extreme. They didn't melt them down or anything. But they did pretty much dismantle them, test each piece for conformance, and put them back together.

Of course, the SRBs also weren't really all that complex, consisting of little more than a tube with a nozzle on one end, and a parachute deployment system under a disposable nose cone on the other. So I guess in that way, it was kind of like scrap metal recovery in that there wasn't much else to recover but the metal tube.

Learn some science and find out how wrong you are.

It seems the more we learn about the Earth, the more we realize just how little we really know.

Just recently, for example, alarming rates of sea-ice melt which had been at first blamed on AGW were accidentally discovered by NASA to be the result of a massive magma plume rising from the mantle under the Antarctic, rivaling Yellowstone's potentially super-volcano-class plume.

https://www.nasa.gov/feature/j...

Humans are not always the cause. How about a little more research before we rush to convict humanity?

I also contend that we, at our current level of scientific knowledge and technology, could not possibly be able to predict the planet's climate 100-200 years out with a level of certainty that would make the risk of the sacrifices people make being useless (or in the case of 'climate engineering' causing massive damage) low enough to be a reasonable and logical decision.

How many critical planetary variables must be tracked/measured, which are they, and to what accuracy must they each be measured in order to predict changes in the global average temperature to within +/- 1C at a point 100 years from now?

You don't know. Nobody knows, not even "climate scientists". We simply do not understand enough about Earth's climate system or the planet itself, not to mention the computing power that would be required to model all the massively-chaotic variables involved on a planet-wide scale.

Nothing wrong with not shitting where you eat, I look forward to more electric vehicles and less air pollution, I want alternate forms of electricity generation where it makes sense from a monetary, engineering, and practicality standpoint. Treating all that as an almost religious crusade attacking any who dare question their dogma as many here do, however, is both illogical and counterproductive. Don't be 'that guy'.

Strat

Weep ye not, for the clever chaps at NASA are developing a new series of fire tubes that will thrust their payloads upwards into the air and penetrate the atmosphere that will be almost as big as Up-Goer-Five (130,000 Kg): https://www.nasa.gov/explorati...

Payload Dummy second stage (S-4), weighing 25,000 pounds, ballasted with 90,000 pounds, 11,000 gallons of water
Dummy third stage (S-5), weighing 3,000 pounds, ballasted with 100,000 pounds, 12,000 gallons of water

Wouldn't that destroy delicate desert habitat and extinct a variety of species?

Not sure if you have noticed... but the Sahara is a bit of a desert. The least number of lifeforms of any ecosystem. Biodensity and biodiversity is very low.

The worst danger is if the winds are no longer able to pick up sand from the Sahara (parts of it are high in nutrients from when the Sahara was a tropical paradise many millennia ago). The sands from the Sahara are currently responsible for feeding the rain forests in South America with certain nutrients. Cut off the sand and the rainforests quickly become weaker. The rainforests are currently ARE high in both biodensity and biodiversity.

Not sure why this is marked as flamebait since it's true. https://www.nasa.gov/content/goddard/nasa-satellite-reveals-how-much-saharan-dust-feeds-amazon-s-plants

Radon and mineral isotopes are fairly localized. Radon is non-existent in vast swaths of the world, as are radio isotopes. As you say, most of the radiation is shielded by the magnetosphere and atmosphere, or most mammalian life on earth would be extinct in a few generations (this is one of the big problems with long distance space travel https://www.nasa.gov/hrp/eleme... ). However, some harmful radiation does make it down to the surface, and over 6000 years, that cumulative radiation damage to the DNA of species is irreversible.

Different creatures have different designed lifespans, and there are a multitude of ways to shorten that lifespan, and very few, if any, ways to lengthen that lifespan. Furthermore, you can shorten an entire population's lifespan with radiation (just ask the fruit flies that were irradiated in the quest for proof of Evolution). And to clarify, I am not just talking about solar radiation RTFP. There are a number of sources of harmful radiation outside the planet.

Ask any scientist about the effects of radiation on health and DNA https://www.nasa.gov/hrp/eleme...

What do you mean? That's like half the world! 50% chance you don't even nee to go anywhere.

Oh man rub some salt in the wound why don't you.
https://eclipse.gsfc.nasa.gov/...

Yeah, the total eclipse isn't visible at all to most of us Europeans, unfortunately. (It'll be visible in Eastern Europe, a little bit, at sunset, but the totality will be over by then).

Nasa always post some good info about eclipses: https://eclipse.gsfc.nasa.gov/...
(Note: All times are in UTC)

The ISS had no compelling reason to be built. ...

One of the reasons not often mentioned was to prevent collapsing Russian empire rocketry know-how to be exported to rogue states.

People point to all the innovations and advancements we made due to going to the moon - and that's a fair assessment - but none of that happened at the ISS.

There are many (you know, just because someone doesn't know about something it doesn't mean it doesn't exist):
In general:
- knowledge about human prolong exposure to micro-gravity in comfortable LEO
- testing equipment to sustain human well being in space in comfortable LEO
- science research in micro-gravity and outside Earth atmosphere
- testing any devices, which require human tuning and micro-gravity or outside Earth atmosphere environment
In detail (a few examples):
- a new deep space navigation system was tested on ISS
- NASA spin offs:
https://spinoff.nasa.gov/flyer...

There are several potential projects that are far more interesting and more worthy, things such as exoplanet exploration rovers, landing on a comet, new and innovative space telescopes, and perhaps other space-based experiments such as laser interferometer gravitational detectors or telescopes based on photon quantum correlation.

I guess you mean just "planets", we are far far from sending rovers to exoplanets.

True, there are lots of extremely interesting concepts and ISS drains lots of resources, however in opinion of many people human exploration beyond Earth is one of them in which case ISS is just the basic we can afford.

> there were a few experiments that could be done on it, but in general it was not a good use of the money.

Who are you? Are able to judge any of the experiences? Are you even understanding the implications of any of the following discoveries?

15_ways_iss_benefits_earth

>People point to all the innovations and advancements we made due to going to the moon

People, the best metric about science. Scientifically speaking, human going on the moon was the most expensive ever thing with a zero ROI. But Good PR, still working today...

The ISS was only designed with a 15 year life expectancy. It is currently about 18 years old (some modules are older, some newer), and by 2025 it'll be 25 years old. NASA figures the absolute deadline is 2028. So 2025 is a good retirement date if you want a safety margin. It's commensurate with a previous NASA study which green-lighted keeping it operational until 2024.

Discussion should be focused on what comes next. Not on how to keep the ISS flying. The Space Shuttle was retired for the same reason - its components were designed with only a max 30 year lifespan in mind. Retrofitting it for longer service would've involved replacing all these parts. And if you're going to do that, you might as well design something completely new that takes advantage of new technology that's been developed in the previous 20+ years.

I found an old storage tank, and I'm pretty sure if I heat water hot enough, I can make it hit the moon. Maybe we can attach a long dable so we can just pull it back when done?

Planning on aiming for the Expiration Date site.

Hmmm. Could you re-post the link and point out where to find the information about the weight? I couldn't find anything abouit Kilopower weights in any links you posted. I did find this source: https://ntrs.nasa.gov/archive/... which has an 8kW kilopower system (NEP prototype) with a mass of 1142kg, which indicates your numbers are in the right ballpark (ignoring output).

I didn't watch the video, but NASA's own published data on sea level seems to agree with the previous assertion. Take a look yourself. That line looks more or less linear to me since the mid 1800's.

I looked at that page and it appears that there was a substantial increase in the rate of sea level rise starting around 1930.

A compact, low cost, fission reactor for exploration and science, scalable from 1 kW to 10 kW electric

Novel integration of available U-235 fuel form, passive sodium heat pipes, and flight-ready Stirling convertors

Would provide about 10x more power than the Multi-Mission Radioisotope Thermoelectric Generator

some perspective :

Power systems used on previous robotic missions (e.g. Spirit/Opportunity, Phoenix, Curiosity) do not provide sufficient power: all less than 200 W

source (with pictures!) : https://www.nasa.gov/sites/def...

If you've done that environmental science work then you should be skilled enough to dig into the literature and discover the answers to your questions. Are you just too lazy to do that? I would suggest you take a look at the GISTEMP. It includes links to papers that talk about the error, spatial coverage, etc.

As far as being accurate to 0.005 degrees F it's not necessary for the individual measurements to be that precise. When you combine a lot of measurements into and average it's reasonable to express it to a higher degree of precision than the individual measurements. The clearest example of that I know of is baseball batting averages. The individual measurements are integers, either a hit (1) or an out (0), yet you commonly see batting averages expressed to 3 decimal places. So well into the season if you get a hit your batting average may rise by 0.002. By the same token in temperature averages subtle changes will appear in the average temperature when they're expressed to more decimal places.

Yes, I prefer my airplanes to be filled with nice safe hydrocarbons. They never burn.

EVs have a lower per-km rate of fires than gasoline cars (various figures suggest around 1/5th the rate). Why would it be any different with aircraft? Furthermore, it's much easier to make components redundant with EVs. Electric motors are light, batteries packs are easy to isolate from each other with no extra weight penalty, etc. In one design NASA has been working on there's a huge number of small props on the wing; they're only run at full power at takeoff, but beyond redundancy, they provide a huge amount of extra lift, greatly reducing takeoff distance. So far, though, they've only built a wing testbed ;)

Yes, I prefer my airplanes to be filled with nice safe hydrocarbons. They never burn.

EVs have a lower per-km rate of fires than gasoline cars (various figures suggest around 1/5th the rate). Why would it be any different with aircraft? Furthermore, it's much easier to make components redundant with EVs. Electric motors are light, batteries packs are easy to isolate from each other with no extra weight penalty, etc. In one design NASA has been working on there's a huge number of small props on the wing; they're only run at full power at takeoff, but beyond redundancy, they provide a huge amount of extra lift, greatly reducing takeoff distance. So far, though, they've only built a wing testbed ;)