Recent comments in /f/space

Spider_pig448 t1_jae1yz9 wrote

Reply to comment by Pigs_in_the_Porridge in We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

It is an issue. ASAT tests and cyber attacks in particular are huge concerns for space debris generation. Regular generation of space junk per launch is decreasing a lot though. Check out ESA's environmental report from last year (https://www.esa.int/Space_Safety/Space_Debris/ESA_s_Space_Environment_Report_2022). Almost every rocker body is successfully clearing LEO these days, and half of all payloads are being successfully de-orbited after end of mission.

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dgames_90 t1_jae1txj wrote

Reply to comment by PhotonicSymmetry in The Case for Callisto by MoreGull

>Mars will never be terraformed and terraforming Mars is a terrible idea.

isn't musk selling this idea? colony with MILLIONS of people?

he isn't the only one, MarsOne comes to mind among many others.

I totally agree with what you say, having small bases like in the artic, or simple mining colonies is feasable and interesting, but the talk here is fully functional independent colonies. that's not gonna happen anytime soon (200++ years).

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Pigs_in_the_Porridge t1_jae12be wrote

Reply to comment by Spider_pig448 in We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

What do you know that the world's space agencies don't? They have publicly expressed concern about space junk in LEO making some orbits, like those around 400 miles or so, unusable at some point in the future. Chinese and Russian ASAT tests have added thousands of pieces of debris. Just saying it's not an issue is not in the least convincing.

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Spider_pig448 t1_jadz6i8 wrote

Reply to comment by snewz404 in We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

eh the policies in place already for combating space junk have resulted in considerable progress in the last five years. The problem of new space junk has already dropped significantly, and if things continue on pace we'll be in a good place in a few years.

The problem of existing space junk is different however.

Here's a great report ESA recently released about progress here https://www.esa.int/Space_Safety/Space_Debris/ESA_s_Space_Environment_Report_2022

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nednobbins t1_jadvzyf wrote

Reply to China to expand its space station, international astronaut selection underway by ye_olde_astronaut

Just how modular is this thing actually?

I initially imagined some small space station with a few interchangeable parts.

Then I read, "The multi-functional expansion module will host six docking ports". That's just 2 short of what ISS has. Is this something that can just keep growing like some video game space station simulator?

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DBDude t1_jadsn35 wrote

Reply to Interesting take on SpaceX’s 2023 Revenue by KotesFolly_

Looks like Starlink revenue may slightly surpass launch revenue, but that Starlink program also has a massive cost, as it'll take up about twice as many launches as SpaceX is getting paid for, plus the cost of the satellites.

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DBDude t1_jads473 wrote

Reply to Why don’t we put air intakes on the lower stages of rockets? by Squiggin1321

A rocket motor needs liquid propellant at best, so no. So like a jet engine first stage? A Falcon 9 is already 40 miles up in less than two minutes. Your jet first stage would maybe be able to get the rocket to 40,000 feet before rockets have to take over, so maybe some tens of seconds of flight. And then we have size/weight issues. Our most powerful jet engine is the GE9X at 110,000 lbs thrust. You'd need several of these to replace rockets, and they're huge and heavy.

The best idea we have so far is to haul a rocket up high on a jet airplane and then launch it, but that only works for smaller rockets.

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macbowes t1_jadrzqy wrote

Reply to comment by RoDeltaR in Black holes may be quietly generating the force that is tearing the universe apart, experts say by dr_gus

Yes! Thank you for sharing this information. The authors of the two papers that have led to this recent news story do not address the question of how black holes, which are made of matter that constitutes a small fraction of 4.6% of all the energy in the universe, are responsible for dark energy, when dark energy comprises 70%~ of all the energy in the universe.

[Dr. Sabine Hossenfelder on this issue.] (https://youtu.be/ENGJA1cUe3M)

Dr. Becky Smethurst on this issue.

An interview with one of the lead authors is available here.

They claim that the reason we see a smooth distribution of dark energy throughout spacetime, despite the supposed source (black holes) obviously not being smoothly distributed throughout spacetime, is because of relativistic effects. Intuitively, one would expect the areas near black holes to be expanding faster than areas far away from black holes, if the cause of expansion was the black holes themselves.

Seems unlikely to me. I am hoping that Dr. Matt O'Dowd of PBS SpaceTime also addresses the topic.

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Bipogram t1_jadq4p9 wrote

Reply to comment by JonesoftheNorth in We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

Perhaps.

But you still need to launch that junk from its current orbit to wherever you want it to go, and then soft-land it (if you're aiming for the Moon).

The average satellite will lack;

a) Fuel/engines to perform such a task

b) the same for capture/soft-braking manoeuvres

c) structures/resources to allow it to land safely (legs, power, etc.)

It's like saying I could go down to the beach, and cobble together a boat from discarded plastic and wood.

I could.

Or I could build a ship.

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