# The Great Ongoing Space Exploration Thread **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Tags:** science-math\ **Created:** [November 16, 2020, 12:18pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703 "2020-11-16T12:18:17Z")\ **Posts on this page:** 20\ **Page:** 69
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 13, 2024, 2:29am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1362 "2024-06-13T02:29:52Z")
“Leaked” audio doesn’t quite describe it. It was played through the ordinary ISS livestream channel with no indication that it was a sim (the article says this, but not the headline). Glad that there was no actual emergency, but it was a pretty big screwup. ---
**Author:** ![Frodo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frodo/32/302_2.png) [@Frodo](https://boards.straightdope.com/u/Frodo)\ **Post date:** [June 13, 2024, 2:34am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1363 "2024-06-13T02:34:02Z")
Let a thousand conspiracy theories bloom! (and may be some SF writer can get some inspiration from this and create something worthwhile) ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 13, 2024, 2:43am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1364 "2024-06-13T02:43:14Z")
I am still wondering how much of this was real. Was the flight surgeon _really_ stuck in LA traffic? Were they really trying to stuff some guy in a suit? Wheels within wheels… ---
**Author:** ![Fiendish\_Astronaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiendish_astronaut/32/3295_2.png) [@Fiendish\_Astronaut](https://boards.straightdope.com/u/Fiendish_Astronaut)\ **Post date:** [June 13, 2024, 5:01pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1365 "2024-06-13T17:01:04Z")
We do these sort of exercises in our work. I can totally believe they happen on the space station. In fact I’d expect them to happen. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [June 17, 2024, 12:29am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1366 "2024-06-17T00:29:15Z")
It’d be inadvisable _not_ to have drills like this - but best not to share them with the whole world. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 17, 2024, 12:51am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1367 "2024-06-17T00:51:58Z")
My _very_ limited experience with these kinds of drills (mostly from the first aid volunteer crew at my workplace) is that they’re highly scripted. I’m a little surprised (and impressed) at the apparent realism of this one. I wonder if the timing was semi-randomized so that people had to be on their toes, at least to some extent. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [June 20, 2024, 4:35am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1368 "2024-06-20T04:35:52Z")
Here’s something which seems totally unworkable to me: > **[Rocket company develops massive catapult to launch satellites into space...](https://www.thecooldown.com/green-tech/spinlaunch-satellite-launch-system-kinetic/)** > > SpinLaunch is developing a large rotating arm that uses kinetic energy to fling 440-pound satellites into low orbit. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 20, 2024, 5:29am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1369 "2024-06-20T05:29:40Z")
We’ve talked a bit about Spinlaunch before. There’s nothing inherently impossible about what they’re claiming. The centrifuge gives them a good boost but doesn’t put them into orbit. For that, they still need a rocket, and they’re developing one for that purpose. Even if the centrifuge could impart enough delta V (it can’t), you’d still need a rocket to circularize the orbit. The gee loads are extreme but artillery shells have electronics and other components and can survive even higher shocks. It’s not an easy engineering problem, but it is possible. My opinion though is that it’s economically unviable. The rocket portion is not free, and it costs more to build a satellite that can survive those loads. This will likely eat any savings you get from the centrifuge system. But hey, it’s an impressive device and I’d like to see it work. And it isn’t perpetual motion or a reactionless drive or anything completely stupid. So I can’t write it off on that basis alone. And possibly they’ll be able to make the rocket super cheap or partly reusable, and some payloads like water or propellant don’t care about acceleration. Perhaps there’s some niche there. ---
**Author:** ![Fiendish\_Astronaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiendish_astronaut/32/3295_2.png) [@Fiendish\_Astronaut](https://boards.straightdope.com/u/Fiendish_Astronaut)\ **Post date:** [June 20, 2024, 8:55am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1370 "2024-06-20T08:55:31Z")
> [@Dr.Strangelove](#): > > The gee loads are extreme Couldn’t the centrifuge accelerate much more slowly? In theory I don’t see why it couldn’t be the gentlest ride up to space available, however I don’t know what the design is for this. Obviously the rocket stage later on would push you back in your seat a bit… ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 20, 2024, 9:08am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1371 "2024-06-20T09:08:08Z")
No; the problem is the outward acceleration (the centripetal force). Think of a merry-go-round: you’re flung toward the outside even when you’ve stopped increasing the rotation rate. Spinlaunch actually can’t increase the rotation rate very quickly because the motors can only produce so much power. This is an advantage in some sense, because one alternative is a linear accelerator, but the problem there is that the power is consumed in a short burst. Spinlaunch stores energy in the spinning itself, and it can “charge” up slowly. That keeps peak power use low (i.e., no need to build it next to a nuclear power plant). They could reduce the acceleration by making the centrifuge larger. Twice the diameter, half the acceleration. But it would have to be gigantic to get within human tolerances. Many kilometers in diameter, since they’d need to get down to about 5 gees, and that’s 2000x as large. Ironically, this is an area where it makes sense to go back to a linear accelerator. Humans can survive ~50 gees for a short duration. Their lungs would collapse and maybe they’d burst some blood vessels, but a healthy young adult would be ok for the time it takes to accelerate. But that wouldn’t work for Spinlaunch, since it spends so much time at a high gee load. Even 5 gees for an extended period is a bit of a stretch. Once the centrifuge releases you, you’re fine. You go from 10,000 gees down to whatever the rocket is at–around 1.5-5 gees, depending on the design. ---
**Author:** ![Fiendish\_Astronaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiendish_astronaut/32/3295_2.png) [@Fiendish\_Astronaut](https://boards.straightdope.com/u/Fiendish_Astronaut)\ **Post date:** [June 20, 2024, 9:42am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1372 "2024-06-20T09:42:25Z")
> [@Dr.Strangelove](#): > > Think of a merry-go-round: you’re flung toward the outside even when you’ve stopped increasing the rotation rate. Of course! You can tell I’m no physicist! I wonder if it’s possible to make an accelerator that proactively tilts it’s angle away from the earth so the object being spun is at the zenith of the tilt at all times? So gravity cancels out the centrifugal force. (Does all this even make sense?) ---
**Author:** ![willthekittensurvive](https://avatars.discourse-cdn.com/v4/letter/w/91b2a8/32.png) [@willthekittensurvive](https://boards.straightdope.com/u/willthekittensurvive)\ **Post date:** [June 20, 2024, 10:48am UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1373 "2024-06-20T10:48:37Z")
Question, if I got one of these on the Moon, would it be an effective weapon? Could one bombard specific places on Earth with Moon boulders? Say Maastricht in the Netherlands, How much impact would a payload have? ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [June 20, 2024, 12:44pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1374 "2024-06-20T12:44:46Z")
> [@willthekittensurvive](#): > > Say Maastricht in the Netherlands #SuspiciouslySpecific ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [June 20, 2024, 5:29pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1375 "2024-06-20T17:29:16Z")
How does a payload survive traveling through the Earth’s lower atmosphere at ~5 miles per second? ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [June 20, 2024, 6:01pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1376 "2024-06-20T18:01:56Z")
Gingerly 😄 ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [June 20, 2024, 6:27pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1377 "2024-06-20T18:27:01Z")
> [@Dr.Strangelove](#): > > You go from 10,000 gees down to whatever the rocket is at–around 1.5-5 gees, depending on the design. Does this produce a wee bit of sonic boom? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 20, 2024, 8:16pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1378 "2024-06-20T20:16:04Z")
> [@PastTense](#): > > Does this produce a wee bit of sonic boom? Yes, but not because of the acceleration. It’s at about mach 6.5 at release, so this definitely produces a sonic boom. Inside the centrifuge it’s a vacuum, or nearly so–they have a membrane that the projectile punches through to exit, and I think eventually they’ll have some fast-acting door. So things do get exciting at exit. I should note that sonic booms don’t happen because an object is transitioning from subsonic to supersonic, or vice versa. They’re actually continuous. We just perceive them as a boom because all the energy is compressed into a shockwave that passes us in a moment. But the shockwave itself is always there, being swept along the ground. > [@Lumpy](#): > > How does a payload survive traveling through the Earth’s lower atmosphere at ~5 miles per second? It’s not quite that fast–more like 1.4 miles/sec. But that’s still pretty fast. It’s encased in a carbon fiber container with a metal tip (looks like a copper alloy from the pics). It should get above the atmosphere pretty quickly, so using a thermally conductive metal should allow it to draw away the heat until air drag isn’t a problem. The X-15 went almost that fast, through to be fair not at sea level. ICBMs do the reverse and they manage to survive. > [@Fiendish\_Astronaut](#): > > I wonder if it’s possible to make an accelerator that proactively tilts it’s angle away from the earth so the object being spun is at the zenith of the tilt at all times? Wouldn’t be of much use. It’s true that the object experiences less force on the upper part of the swing than the lower. Same reason you feel weightless going over a hill on a roller coaster, and heavier going through a valley. But it averages out to the same amount, so it won’t help you any. The other reason is that gravity is just tiny compared to the centripetal force. It’ll experience 9,999 gees at the upper part of the swing and 10,001 gees at the lower. Just not enough to consider. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [June 21, 2024, 3:17pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1379 "2024-06-21T15:17:21Z")
> **[Remembering Allan McDonald: He Refused To Approve Challenger Launch, Exposed...](https://www.npr.org/2021/03/07/974534021/remembering-allan-mcdonald-he-refused-to-approve-challenger-launch-exposed-cover)** > > Allan McDonald, who directed the booster rocket project at NASA contractor Morton Thiokol, urged delaying the launch of the space shuttle before it exploded in 1986. He has died at age 83. This was a 2021 article I thought interesting. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 22, 2024, 9:07pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1380 "2024-06-22T21:07:58Z")
This is fine: > > > China 'N Asia Spaceflight 🚀𝕏 🛰️ @CNSpaceflight Don’t worry–the orange stuff is just nitrogen tetroxide. Perfectly safe. Kids drink the stuff. Nothing to see here. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [June 22, 2024, 9:32pm UTC](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703/1381 "2024-06-22T21:32:24Z")
I hope nitrogen tetroxide at least doesn’t persist in the environment thanks to its high reactivity. [Previous page](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703.md?page=68) [Next page](https://boards.straightdope.com/t/the-great-ongoing-space-exploration-thread/925703.md?page=70)