For Questions That Don't Merit Their Own Thread

[p1t1o]

F117's design was highly limited by computattional techniques and lack of raw processing power.

Once computers were good enough, curved, more aerodynamic designs were possible.

There are internal structural features (such as the famous "re-entrant triangles") but you won't find an f117 under the skin of a b2 or f35.

Stealth capability and radar signiture tracks very well with technological progress, essentially, newer aircraft are better at it. Hence f35 more stealthy than f22.

Stealth always a trade-off, f22 or 35 could easily be made more stealthy, but at cost of speed, range,anouverability etc etc

 

 

[magnemoe]

1 hour ago, kerbiloid said:

The F-35 composition, in turn, makes to ask.
If all you need to get a normal fine stealth, is to put plastic spoilers on the ugly angular F-117, why did they make us suffering in Microprose F-117 trying to not fall down on this flying grotesque, rather than make a normal plane from the very beginning and let Microprose make a notmal aircraft game...

Now I remember that old game, the amusing part was the low polygon in-game model was far more like the real thing than the box art  

Now I played the original game, it was re-released after it became famous in gulf war 1. 

Edited August 10, 2020 by magnemoe

[magnemoe]

1 hour ago, p1t1o said:

F117's design was highly limited by computattional techniques and lack of raw processing power.

Once computers were good enough, curved, more aerodynamic designs were possible.

There are internal structural features (such as the famous "re-entrant triangles") but you won't find an f117 under the skin of a b2 or f35.

Stealth capability and radar signiture tracks very well with technological progress, essentially, newer aircraft are better at it. Hence f35 more stealthy than f22.

Stealth always a trade-off, f22 or 35 could easily be made more stealthy, but at cost of speed, range,anouverability etc etc

Also maintenance cost who is probably most of the cost of an military plane lasting decades.

Stealth is not an all or nothing is like camouflage, it make you harder to detect, in short planes can get closer to radars and not getting picked up. 
Now stronger radars and larger radars using longer wavelengths work better but its not something you can put in an missile or fighter jet. 
As I understand it has been exercises there F-22 has homed in on F-16 radar and done gun kills. Yes the radar might pick up the F-22 couple of km out but to late to evade. 
So if you fight an stealth fighter it might be better to have you radar off as then both has to use mark 1 eyeballs or IR detectors and stealth is also about reducing IR but not so much for fighters. 
Rumor that the IR monitoring satellites can pick up planes on afterburner and heavy artillery. 

[SOXBLOX]

2 hours ago, p1t1o said:

F117's design was highly limited by computattional techniques and lack of raw processing power.

Once computers were good enough, curved, more aerodynamic designs were possible.

There are internal structural features (such as the famous "re-entrant triangles") but you won't find an f117 under the skin of a b2 or f35.

Stealth capability and radar signiture tracks very well with technological progress, essentially, newer aircraft are better at it. Hence f35 more stealthy than f22.

Stealth always a trade-off, f22 or 35 could easily be made more stealthy, but at cost of speed, range,anouverability etc etc

Actually, although the actual RCS is classified, I'm pretty sure the F-22 has slightly better all-aspect stealth. F-117 was designed using equations modelling stealth with flat, planar surfaces. Modern (classified) techniques handle curves and more complex shapes.

And threat receivers look for repeating patterns in radio wavelengths. By cycling and not repeating a pattern, LPI radars have a chance of not being detected by their target, so stealth fighters with these equipped can still track adversaries actively.

[DDE]

2 hours ago, magnemoe said:

Also maintenance cost who is probably most of the cost of an military plane lasting decades.

Don't forget six different kinds of gloves for the maintenance team. RAM ciating is a chore, and on a lot of Raptors it already looks rather worn if not outright sloughing off.

Spoiler

 

 

Coincidentally the Su-57 is criticized for its passive infrared sensor compromising its stealth qualities - and it's located in that exact position.

Spoiler

 

[K^2]

6 minutes ago, DDE said:

Don't forget six different kinds of gloves for the maintenance team. RAM ciating is a chore, and on a lot of Raptors it already looks rather worn if not outright sloughing off.

I always thought F-22s sound like they're scraping against something while flying at high speeds. I never realized it was going to be THAT literal. XD

[DDE]

But what if we used the Buran? Anyone know what u/syzygy goes by on this forum?

ODU's main engines are 17D12, syntin-lOx staged combustion for ISP = 362 sec.

Extended tankage modules are items 12 and 9 on this model:

[kerbiloid]

So, the extended tanks add just several hundred m/s, and the wings will most probably crack off on reentry.

A pure military craft for LEO, with no other real purpose.

(Unless they could implement the original idea of reusable Energy, but they couldn't)

Edited August 11, 2020 by kerbiloid

[Nightside]

 

12 hours ago, DDE said:

But what if we used the Buran? Anyone know what u/syzygy goes by on this forum?

He is called @illectro

[magnemoe]

10 hours ago, kerbiloid said:

So, the extended tanks add just several hundred m/s, and the wings will most probably crack off on reentry.

A pure military craft for LEO, with no other real purpose.

(Unless they could implement the original idea of reusable Energy, but they couldn't)

Yes, Scott explained how they could used the external tank for refueling in LEO. 
Who is very Kerbal. 

Minmus expess to the left docked to Moonshadow. To the right the fuel depot or an Saturn 5 extended first stage. 
Its something who feel right launching an gigantic space station on an Saturn 5 using four Soyuz boosters with crossfeed and on shuttle engine on each

no the shuttle could not return from the moon and using some other shuttle concepts like an reusable Saturn 5 first stage and smaller drop tank would been cooler. 
Still something like my Minmus express would be an better way to get to the moon and back. 

[DDE]

40 minutes ago, magnemoe said:

no the shuttle could not return from the moon and using some other shuttle concepts like an reusable Saturn 5 first stage and smaller drop tank would been cooler. 

You'd think an alt-history space story would be more alt, yes.

[StrandedonEarth]

Dayum...

https://www.ucf.edu/news/broken-cable-damages-arecibo-observatory/

 

[ARS]

Does muzzle-loading cannons (like those installed en masse on the broadside of sail-era warship and used in American civil war) has any kind of sighting system to aim the gun? Or is it simply just point a bunch of them in the general direction of the enemy, fire a barrage and hope for the best?

[K^2]

No historical background on this whatsoever, but without rifling and with gun powder charge varying from shot to shot, I don't know if actual sights will do any better than sighting along the body of the barrel and calling it good enough.

[DDE]

38 minutes ago, ARS said:

Does muzzle-loading cannons (like those installed en masse on the broadside of sail-era warship and used in American civil war) has any kind of sighting system to aim the gun? Or is it simply just point a bunch of them in the general direction of the enemy, fire a barrage and hope for the best?

The sights were beginning to show up, although not sytematically. It's somewhere in here:

 

[JoeSchmuckatelli]

On 8/5/2020 at 1:12 PM, DDE said:

https://www.twitter.com/roscosmos/status/1291023063404994560/

That's a big crater.

Is the oblong shape due exclusively to how the material was warehoused, or did the fact that it almost immediately reflected off the grain elevator help shape the crater? 

[ARS]

The Orion Drive works by throwing nuclear bombs to explode behind the ship to provide massive propulsive power to the ship. I've read that Orion drive has one major engineering challenge to provide cushioning to dampen the shockwave from explosions in order to keep the G-forces for the crew at safe level. Since the system works by periodically throwing nuclear bombs behind, and since the explosion instantly provides a massive acceleration to the ship, this also means that the G-forces that's experienced by the crew is sudden (So.. for example, we're at 0G, then after the first bomb explodes, it's suddenly 9G, then 15G, then 17G... you get the idea). My questions is:

1. What would happen to human body if instantly exposed to high-G condition in space? (So far, the most common high-G effect that's experienced on earth is from intense maneuvering on aircraft, which is gradual increment instead of instantaneous)

2. Instead of making a dampening system to reduce the shockwave to a safe level for humans aboard, is it possible to just provides a dampening system just to keep the ship's structural integrity safe during acceleration while the crew uses liquid immersion to dampen the G-forces?

[DDE]

1 minute ago, ARS said:

1. What would happen to human body if instantly exposed to high-G condition in space? (So far, the most common high-G effect that's experienced on earth is from intense maneuvering on aircraft, which is gradual increment instead of instantaneous)

Ha-ha, nope. Try 46.2 g.

https://en.wikipedia.org/wiki/John_Stapp

[kerbiloid]

2 hours ago, ARS said:

What would happen to human body if instantly exposed to high-G condition in space?

We would call him Epstein and copy his drive.

2 hours ago, ARS said:

Instead of making a dampening system to reduce the shockwave to a safe level for humans aboard, is it possible to just provides a dampening system just to keep the ship's structural integrity safe during acceleration while the crew uses liquid immersion to dampen the G-forces?

Iirc this was being discussed in this thread a month or two ago.

[ARS]

26 minutes ago, kerbiloid said:

irc this was being discussed in this thread a month or two ago.

I didn't specify that one back then for orion drive application though

 

[magnemoe]

3 hours ago, ARS said:

The Orion Drive works by throwing nuclear bombs to explode behind the ship to provide massive propulsive power to the ship. I've read that Orion drive has one major engineering challenge to provide cushioning to dampen the shockwave from explosions in order to keep the G-forces for the crew at safe level. Since the system works by periodically throwing nuclear bombs behind, and since the explosion instantly provides a massive acceleration to the ship, this also means that the G-forces that's experienced by the crew is sudden (So.. for example, we're at 0G, then after the first bomb explodes, it's suddenly 9G, then 15G, then 17G... you get the idea). My questions is:

1. What would happen to human body if instantly exposed to high-G condition in space? (So far, the most common high-G effect that's experienced on earth is from intense maneuvering on aircraft, which is gradual increment instead of instantaneous)

2. Instead of making a dampening system to reduce the shockwave to a safe level for humans aboard, is it possible to just provides a dampening system just to keep the ship's structural integrity safe during acceleration while the crew uses liquid immersion to dampen the G-forces?

Not only the crew but also the equipment, yes you can harden it for lots of g but its hard especially for payloads. 
As I understand the shocks would be tolerable, more like an standard space launch, it will be bumpy rather than an constant thing. 
It has an two layer shock absorber, first on is just behind the pusher plate and then the long ones.
Think you could have an 3rd damper between the magazine and the payload and crew. 
It would have to be an active system out of phase with the blasts so you are moving forward the the blast happen, now downside of this in negative g unless you let the pusher plate comes to rest between each blast. 

[kerbiloid]

Orion was designed to keep the crew under 1 g by two-stage piston system.

[Codraroll]

So, even setting aside launch costs, satellites are fiendishly expensive to build. But that's mostly because they need to work in the conditions of space, after the conditions of a space launch, without damaging the rocket launching them or otherwise being a nuisance.

But if you didn't want your satellite to actually do anything, how cheap could you build something a launch provider would be willing to launch? If you just want your name written on a cubic strut somewhere in space, for instance. Would it be possible to just weld together something in a garage and take it to the launch provider for payload integration? In short, what's the absolute minimum cost of a satellite? Let's exclude cubesats since they are too small to be fun. We're talking something that would be launched on its own rocket.

[magnemoe]

1 hour ago, Codraroll said:

So, even setting aside launch costs, satellites are fiendishly expensive to build. But that's mostly because they need to work in the conditions of space, after the conditions of a space launch, without damaging the rocket launching them or otherwise being a nuisance.

But if you didn't want your satellite to actually do anything, how cheap could you build something a launch provider would be willing to launch? If you just want your name written on a cubic strut somewhere in space, for instance. Would it be possible to just weld together something in a garage and take it to the launch provider for payload integration? In short, what's the absolute minimum cost of a satellite? Let's exclude cubesats since they are too small to be fun. We're talking something that would be launched on its own rocket.

Its an name for it: Mass simulator, usually its an concrete block I think but Rocket lab launched an disco ball object and spaceX sent the tesla testing Falcon heavy. 
You will need an payload adapter on this and an way to separate from second stage but I think its the second stage who does this. 
Lots of mass simulators does not separate as its just there to add an realistic payload weight. 

[DerekL1963]

8 hours ago, Codraroll said:

Would it be possible to just weld together something in a garage and take it to the launch provider for payload integration?

No.  The payload provider is generally responsible for providing the required adapter and separation hardware (if any).  Even if it's just an adapter to support a inert payload, it's still precision machining.  Even if it's an inert adapter and payload, there's various certifications and proof testing required by the launch provider.  Even a cubesat, with everything but the payload proper provided by the integrator, is going to have certain minimum requirements - and proof (paperwork) that the payload meets those requirements.  Most providers and integrators have a user's guide online, so you can look up the requirements.

Then there's the cost of all the paperwork...  With the launch provider, potentially with the launch site, almost certainly with the responsible government agency.  After the Swarm Technologies fiasco in 2018, I suspect few launch providers will risk a launch without ensuring all the requisite paperwork is complete.

tl;dr  There's a certain minimum cost, and you're not going to pay it with change from your couch cushions.  Without detailed information, it's difficult to give a reasonable floor or range for the minimum cost.