The thread for space cadets!

[Broken_Erika]

So, r16 was influenced by an F16 thing he read when he was 16?

 

[Imaus]

I'm also seeing a lot of hubbub about how NASA needs more; a lot more, because the ''real" value of the money is not comparable at a face value to what was done with Apollo. It doesn't help matters that basically no-one from the Apollo era is working in NASA anymore and like always NASA has to rebuild everything from scratch; just with a shinier and more modern backdrop to choose from.

 

[hobbsyoyo]

The comparison with Apollo is unfair. We're light years ahead of where they were back then and for the kind of mission NASA is currently planning, it shouldn't cost more than Apollo unless they were doing it very, very wrong. But politics are involved so you can't discount gross mismanagement.

All that said, it isn't enough money and it's doubtful this program would survive a presidential handover. Although it did survive Obama's attempts to kill it, so who knows? It's a powerful jobs program, if exceedingly wasteful and badly run.

The important thing right here and now is that they have an actual plan they're working toward. Giving it a name was more than symbolic; I really think it means that everyone in NASA is congealing around a real game plan. Until now, everything's been exceedingly wishy-washy and none of the NASA centers involved were really being held accountable for how badly they were allowing Boeing et al to run things off the rails.

Bridenstine has really taken those centers to task and given the whole agency a direction to march in. He's literally the only good thing about the Trump administration in my opinion. He went from climate change denier while in Congress to a big proponent of NASA climate change missions and has defended his LGBT workforce from punitive Trump edicts.

It's not a great game plan but it's a plan. And most importantly, they've taken big steps to open it up to American industry even outside of the big traditional players like Lockheed and Boeing. They're also successfully rallying international allies like Canada to the mission and if they some how make it to launch next year, I think the program might have a chance of hitting the moon in 2024.

 

[r16]

So, r16 was influenced by an F16 thing he read when he was 16?

r16 at 16 was the very same idiot , badly desiring to be an aircraft engineer now that his windowpane thick and size prescription glasses would not just disappear in a year to let become a fighter pilot ; and ı have actually seen F-14s in flight and F-16 was a very secondary option but would have to . Can't speak Farsi , won't become an American . Where's the damned spider to bite you , when you need one ?

and yeah a very slow day , so ı have decided to troll WW 1 historians . Aerial Fighting back then had distinct phases . Where the Allies can shoot the Germans and when Germans can shoot back , the latter periods getting defining stuff like "scourge" or "bloody" . So , Germans being Germans examine statistics and the lot and decide to fight to conserve their forces and equipping/training/commanding themselves accordingly . So , Allies consider them -naturally- cowards and backstabbers . They fight only when they outnumber the gallant Allies if they have so many to Allies' too few . So , when Werner Voss is brought down after some epic fight in which he engages upto 11 planes , hits 7 and causes 4 of them to be scrapped , it's so unfitting that , it's just natural he would be credited with extra stuff . Readily ignored by later time historians .

but being a pseudo-expert is not easy . So a proto-proto-proto-proto MiG-28 . Rhys-Davies or Davids , the British pilot credited with shooting Voss down , possibly the supreme aerobatic pilot of the War , describes the Dreidecker with 4 machine guns and armour plate as at one point fired on by 5 British planes and tracers from 10 machine guns converging . While the wreckage of Voss had only 2 fresh bullet holes on the rudder and 3 wounds on him ... The bathtube of A-10 is titanium and weighs some 520 kilograms , it would take about the same volume to keep engine, cockpit and fuel tanks in a WW I plane and could perhaps be achieved at about 200 kilograms ; while Bf-109 started with 3 machine guns in the 1930s . The crowning description then naturally goes to the engine , Rhys-Davies describes it as a stationary but not a Mercedes , because being at 100 metres to it , he would see it "didn't" have the Rotary gap for cooling and he didn't know such engines would soon be called Radials . Because , obviously you would need 400 horses and up and up to have the climb rate for Voss to get up rocket like , have a look at the 12 to 15 Albatross planes milling around , worried about more Allied planes that would jump them if they joined the scrap , so dived back to his death . Being a pseudo-expert being not easy , ı could also claim his two way radio contact with a recon plane might have also compelled him to rejoin the fight . Even more amazing thing is deadly aim , for in wrecking 4 planes he didn't scratch a single pilot . (No, it didn't happen.)

 

[Thorgalaeg]

The comparison with Apollo is unfair. We're light years ahead of where they were back then and for the kind of mission NASA is currently planning, it shouldn't cost more than Apollo unless they were doing it very, very wrong. But politics are involved so you can't discount gross mismanagement.

All that said, it isn't enough money and it's doubtful this program would survive a presidential handover. Although it did survive Obama's attempts to kill it, so who knows? It's a powerful jobs program, if exceedingly wasteful and badly run.

The important thing right here and now is that they have an actual plan they're working toward. Giving it a name was more than symbolic; I really think it means that everyone in NASA is congealing around a real game plan. Until now, everything's been exceedingly wishy-washy and none of the NASA centers involved were really being held accountable for how badly they were allowing Boeing et al to run things off the rails.

Bridenstine has really taken those centers to task and given the whole agency a direction to march in. He's literally the only good thing about the Trump administration in my opinion. He went from climate change denier while in Congress to a big proponent of NASA climate change missions and has defended his LGBT workforce from punitive Trump edicts.

It's not a great game plan but it's a plan. And most importantly, they've taken big steps to open it up to American industry even outside of the big traditional players like Lockheed and Boeing. They're also successfully rallying international allies like Canada to the mission and if they some how make it to launch next year, I think the program might have a chance of hitting the moon in 2024.

Who would have said in 1969 we would be struggling to reach the moon in 2024.

 

[hobbsyoyo]

Congress (the House) took a whack at the budget and they are removing funds for the lander, pushing the landing back to 2028. The budget has multiple rounds of iterations before it becomes law (if it does become law - who knows what will happen with this government) so this isn't the final word yet.

I also found out that in addition to raiding funds from Pell Grants to pay for the landers, Trump was also proposing deep cuts to certain science divisions in NASA. Congress put those funds back where they were and have no interest in accelerating the moon program. They are content to let it peddle on to nowhere as it has for the last two decades. It's great for employment in Texas, Alabama, Mississippi and Florida, at least.


----------


Turns out Boeing new about all sorts of issues with the 737 Max and still flew it. Also, they were charging something like $4k to add an LED that would light up to tell the pilots when their auto-trim system was malfunctioning.

 

[Imaus]

Congress (the House) took a whack at the budget and they are removing funds for the lander, pushing the landing back to 2028. The budget has multiple rounds of iterations before it becomes law (if it does become law - who knows what will happen with this government) so this isn't the final word yet.

I also found out that in addition to raiding funds from Pell Grants to pay for the landers, Trump was also proposing deep cuts to certain science divisions in NASA. Congress put those funds back where they were and have no interest in accelerating the moon program. They are content to let it peddle on to nowhere as it has for the last two decades. It's great for employment in Texas, Alabama, Mississippi and Florida, at least.


----------


Turns out Boeing new about all sorts of issues with the 737 Max and still flew it. Also, they were charging something like $4k to add an LED that would light up to tell the pilots when their auto-trim system was malfunctioning.

Trump won't let 2028 be the final moniker, for sure. If he has any political capital left, he might just turn on the heat on this. "Why are we falling behind? Why are we giving it all to China? Why are we stagnating? Blah blah blah blame Socialists here". He wants 2022 because that's when his second term, should he win *and of course he believes he will win* will almost be ending and in the lame duck phase. A moon landing gives him one last hurrah to give one last, self-gloating speech.

 

[hobbsyoyo]

As noted, the budget he proposed wasn't enough to get this done and shuffled funds around in a way that was begging Congress to reject it. He has no clue what he wants or how to get it done.

 

[Berzerker]

https://phys.org/news/2019-05-giant-impact-difference-moon-hemispheres.html

Now, new evidence about the Moon's crust suggests the differences were caused by a wayward dwarf planet colliding with the Moon in the early history of the solar system.

They found the best fit for today's asymmetrical Moon is a large body, about 480 miles (780 kilometers) in diameter, smacking into the nearside of the Moon at 14,000 miles per hour (22,500 kilometers per hour). That would be the equivalent of an object a bit smaller than the dwarf planet Ceres moving at a speed about one-quarter as fast as the meteor pebbles and sand grains that burn up as "shooting stars" in Earth's atmosphere. Another good fit for the impact combinations the team modeled is a slightly smaller, 450-mile (720-kilometer) diameter, object hitting at a mildly faster 15,000 miles per hour (24,500 kilometers per hour).

https://aasnova.org/2017/02/14/dont-blame-asteroids-for-the-late-heavy-bombardment/

That link says asteroids and comets were not the (main) culprit for the late heavy bombardment, just material leftover from the planet forming process. In other words, they dont really know.

I have a question for our budding astronomers: if the Moon was hit by debris from large impactors striking the Earth, how fast would that material be moving when it hit the Moon?

Apparently they think the minor planet sized rock that hit the Moon was traveling 1/4th as fast as smaller debris entering our atmosphere. Why the difference? Could it be impacts on Earth threw material into the Moon and thats why one side of the Moon was hit hard excavating several miles of crust depositing it on the other side?

 

[hobbsyoyo]

Material ejected from the Earth that hit the Moon would be around escape velocity, 11.186 km/s, give or take. Some would be slower (but not much less slower to be able to get all the way to the Moon) and some would be much faster. There would also be a difference in impact velocity caused by the moon's own orbital velocity, dependent on the impact angle.

I would guess that the thing that smacked the moon would be nearly co-orbital and thus the differences in speed would be much less than rocks coming in on crazy ass trajectories that combine with the Earth's own orbital velocity.

 

[Berzerker]

thats true, race cars travel fast but not so much relative to each other

 

[Berzerker]

https://phys.org/news/2019-05-formation-moon-brought-earth.html

The measurements made by the researchers from Münster show that the molybdenum isotopic composition of the Earth lies between those of the carbonaceous and non-carbonaceous meteorites, demonstrating that some of Earth's molybdenum originated in the outer solar system.

Now thats interesting. Their explanation is Theia (impactor resulting in the Moon) came from further out in the solar system and was therefore richer in water bearing carbonaceous material. There is another explanation, the Earth came from further out in the solar system. If the Earth's molybdenum is between the dry inner solar system and wet outer solar system, the Earth may have formed between the two zones. Thats where the asteroid belt is located, thats where the dry inner solar system met the wetter outer solar system. Thats where the early solar system's 'freeze line' was located, where gas being blown out by the solar wind began condensing and freezing.

I'd expect the solar system's first planet to form there surrounded by condensing gas, surrounded by water. I'd like to know how far out they think Theia formed, I wont be shocked if they determine the asteroid belt was its original location.

edit: no, Theia would have to be more distant to make up for the Earth's alleged lack of isotopic molybdenum. That would it put it in Jupiter's vicinity.

 

[Imaus]

Planets truly are wanderers.

 

[red_elk]

Explanatory letter by Roscosmos:
"If the satellite was properly sanctified, but didn't make it to the orbit, it means it was sinful and doesn't belong to Heavens anyway"

 

[hobbsyoyo]

https://phys.org/news/2019-05-formation-moon-brought-earth.html



Now thats interesting. Their explanation is Theia (impactor resulting in the Moon) came from further out in the solar system and was therefore richer in water bearing carbonaceous material. There is another explanation, the Earth came from further out in the solar system. If the Earth's molybdenum is between the dry inner solar system and wet outer solar system, the Earth may have formed between the two zones. Thats where the asteroid belt is located, thats where the dry inner solar system met the wetter outer solar system. Thats where the early solar system's 'freeze line' was located, where gas being blown out by the solar wind began condensing and freezing.

I'd expect the solar system's first planet to form there surrounded by condensing gas, surrounded by water. I'd like to know how far out they think Theia formed, I wont be shocked if they determine the asteroid belt was its original location.

edit: no, Theia would have to be more distant to make up for the Earth's alleged lack of isotopic molybdenum. That would it put it in Jupiter's vicinity.

I'm reading a book on planet formation and so far it seems like Earth developed more or less where it is now.

About 50% of stars have so-called super-Earths that hug their stars. These started out roughly where Venus, Earth and Mars are but rapidly move toward the star due to gas dynamics in the protoplanetary disc and gain a lot of mass in the process. Sometimes they also pick up dense atmospheres and become more like mini-Neptunes than super-Earths.

What makes the solar system special in this regard is that we have Jupiter, which kept the Earth and the other rocky planets from sliding into close orbits about the Sun. Saturn, in turn, kept Jupiter mostly where it is (and kept it from wrecking the rest of the system) though those two did a dance for a bit that messed with Uranus and Neptune and pushed them further away from the Sun.

 

[Berzerker]

I'm ill-informed on the processes and just shooting the breeze so to speak, but I've been keeping up on the research and there do seem to be very large planets orbiting amazingly close to their stars. Our system appears to be a bit uncommon, but maybe thats just because of incomplete data since smaller more distant planets are harder to detect. But wouldn't the amount of dust and gas in the collapsing nebula determine the make up of any planets?

For example, you mentioned the drag from gas on forming planets shortening their orbits. I'd expect the density of the gas/dust cloud to result in the number of planets and their locations. More material means more drag and bigger planets, while a star that barely has enough material to become a star would have fewer, smaller planets orbiting it.

Regarding Earth's formation, I think its more than a coincidence an asteroid belt occupies the solar system's freeze line. Maybe Jupiter and Saturn weren't the giants they are now but grew larger when the asteroid belt formed from a series of massive collisions resulting in the late heavy bombardment. Its of great interest to me that researchers keep importing material from the asteroid belt to explain earthly phenomenon and now they're even importing the Moon from a more distant orbit.

 

[hobbsyoyo]

Part of the 'big planets orbiting close' conundrum is that right now, those are the planets most likely to be detected. We need more and better instruments to understand the true make up of most solar systems as we can't really see Earth-sized or smaller planets in distant orbits.

The size and density of the disc does of course play a big role in the formation of planets but there are a lot of secondary effects that drive things. The planets all play with each other gravitationally and also interact with the disc gravitationally and aerodynamically and this seems to drive the final result almost as much as the initial conditions. It's very strange to read this book and see equations and concepts from rocket/airplane design (gas dynamics) show up but used on such a bigger scale. Also, passing stars and massive rogue planets also play a role, as do any binary stellar pairs.

I actually just read that one of the best known systems (with 4 or 5 planets) has a distant (1000 AU) brown dwarf stellar companion that causes the plane of all of the planet's orbits to flip head over heels in unison every 30 million years.

The asteroid belt in our system exists because Jupiter was big enough to stop Mars from growing and gobbling it up and also stopped another planet from forming in that region.

 

[Thorgalaeg]

Jupiter is the solar system bully.

 

[hobbsyoyo]

And savior and life bringer.

It brought water to the Earth by flinging water-rich outer belt rocks at it and then kept the whole system stable so planets stopped colliding and moving around.

 

[hobbsyoyo]

As far as I know, that's the first time in history something like this has been seen by mankind. It's really remarkable.

Background:
SpaceX is launching (no pun intended) a satellite-based internet service. They are going to build a network of around 10,000 satellites in LEO with laser communications crosslinks (means they can route internet traffic between each other without using ground stations) and electronically steered beam antennas to cover the Earth with gigabit-class, low-latency internet.

They launched two demonstration units last year and just this week they launched 60, 200+ kg satellites into LEO. These satellites do not have the laser crosslinks but collectively they generate more power than the ISS and can provide about a terabit of throughput and they all have advanced Krypton electric thrusters they will use to climb to their operational altitude. Here they are, flat-packed in the fairing and being tossed off the rocket:

Spoiler :

This was the heaviest payload the Falcon has ever launched.


SpaceX is not the only would-be provider of space internet. A company called OneWeb is building a similar network and has set up a factory in Florida to build them. They have also launched the first batch of satellites for their constellation as well. Amazon also announced their own satellite internet initiative called Project Kuiper that will be roughly the same size as SpaceX's and OneWeb's efforts and will be launched by Blue Origin - Jeff Bezos's rocket company.