NASA SLS/Orion/Payloads

[YNM]

13 minutes ago, Canopus said:

NH just shows how much information you can gather from a single flyby. ...

... And how much more you *could* have got with an orbiter.

13 minutes ago, Canopus said:

... The lander they had invisioned wouldn‘t have penetrated the ice more than a meter or something so the idea that it could have found Europan sea slugs is wrong anyway. In the end the Orbiter would have collected more data of the moon than the lander ever could.

True that. I hoped for an orbiter. The lander would much better be impactors if I'm honest. Just how we did stuff on our own Moon.

Edited March 4, 2018 by YNM

[Canopus]

12 minutes ago, YNM said:

... And how much more you *could* have got with an orbiter.

True that. I hoped for an orbiter. The lander would much better be impactors if I'm honest. Just how we did stuff on our own Moon.

There is a reason that it‘s doing flybys instead of orbiting Europa, and thats radiation. So in the end the flyby approach will most likely lead to a longer mission, ergo more information about Europa. Also have you seen the flyby paths? They cover pretty much the whole moon. Nothing an orbiter could have done much better.

Edited March 4, 2018 by Canopus

[Bill Phil]

1 hour ago, YNM said:

... And how much more you *could* have got with an orbiter.

True that. I hoped for an orbiter. The lander would much better be impactors if I'm honest. Just how we did stuff on our own Moon.

It is an orbiter. Of Jupiter. With many planned Europa flybys. 

[DDE]

2 hours ago, Canopus said:

The lander they had invisioned wouldn‘t have penetrated the ice more than a meter or something so the idea that it could have found Europan sea slugs is wrong anyway.

That gives me an idea.

How much dV can you bleed off by cryolithobraking?

[PB666]

4 hours ago, Nibb31 said:

Do you have any idea how hard it is to land on Europa, and how much dV you need to carry ?

Obviously he doesn't.

[YNM]

2 hours ago, Canopus said:

There is a reason that it‘s doing flybys instead of orbiting Europa, and thats radiation. So in the end the flyby approach will most likely lead to a longer mission, ergo more information about Europa. Also have you seen the flyby paths? They cover pretty much the whole moon. Nothing an orbiter could have done much better.

 

1 hour ago, Bill Phil said:

It is an orbiter. Of Jupiter. With many planned Europa flybys. 

Well, why not launch it now on an Atlas V ? Or (well) an FH ?

 

What's the point of launching it on SLS ?

Edited March 4, 2018 by YNM

[Canopus]

2 minutes ago, YNM said:

 

Well, why not launch it now on an Atlas V ? Or (well) an FH ?

 

What's the point of launching it on SLS ?

Well thats why we are currently talking about it again. It seems like it‘s now being launched on an Atlas V 551. The difference is that with SLS it would have taken maybe less than 2 years to get to Jupiter instead of flying a veega trajectory, which takes something like 6 years or longer. Of course it would have been cool to see it arrive so soon, but with SLS‘s low launch cadence, it is more sensible to keep it for missions that absolutely do need it like the current planned construction of the Gateway.

[PB666]

dV is not the primary problem, modern ION driven craft can generate that amount of dV, easily. There's no power, unless you are going to scavenge excess power from your KW decay reactor. The problem is where to get an impulse to circularize Europa and only chemical fuels have enough thrust to land. Its a combination of problems . . . in adequate thrust and dV from the same propulsion unit.

I repeat this over and over again and its mainly directed at the Mars dreamers. You can tell me anything, 100,000 dV to land on a Jovian mega storm, . . . .just tell me first where the power comes from. Most of the arguments have begun with . . . .fusion . . . .

Solar power is eff. k_insolance/d² were in sol distance units its 1400 w/m² / 5.2² = 51.77 x 0.4 (very optimistic efficiency) = 20.8 w/m²

This basically means that there is not enough insolance at Jupiter to justify carry the weight of a solar panel to drive and ION drive. Lets see what I mean N = 2 * (0.8 eff) * P/exhaust velocity. Lets set this at 88,000 (the max current for ION drive), N = 3.3 x 10^-4 (This is not acceleration thats force) To feed a single high performance drive you would need 2000 m² of solar panel, the fuel and the weight of the drive.

So no fusion, no solar, fission only up to 1 kw, H2/O2 bleed-off, O2 bleed off, and so we are now down to a limit of ISPs to about 300 given Nitogen tetroxide or hydrogen peroxide as an oxidant.

If there is an assumption that fuel tanks are at least 5% of the weight of the fuel there is a theoretical limit of about 9000 dV for fuel/engine combos of 3000 m/s exhaust velocity. If half the remaining weight is fuel tank its 7000 dV. If half the weight of the vehicle is fuel its 2079 dV.

[DAL59]

You cannot actually find life though unless you land.  

[DDE]

If anything, a slower trajectory simplifies things for the lander.

3 hours ago, PB666 said:

H2/O2 bleed-off, O2 bleed off, and so we are now down to a limit of ISPs to about 300 given Nitogen tetroxide or hydrogen peroxide as an oxidant.

Maybe 350 if you were to resurrect the esoteric field of deep-space high-energy chemical rocketry that right about died with the Saturn V probe concepts. After all, someone was insane enough to bubble ClF3 through liquid fluorine.

No, I'm not letting go of insane chemistry. The touted upper limit of storeables is somewhere in the 380-400 range planned for the RD-5xx series using peroxide and pentaborane, beryllium hydride, or a hydrazine-beryllium gel. Yes, I've come across Glushko's correspondence asking for a new site at which he could fire those.

[Canopus]

10 minutes ago, DAL59 said:

You cannot actually find life though unless you land.  

No problem, you just take the hourly BFR flight to Europa and start digging with your spade. If you find something that moves, you know it‘s alive.

[Starman4308]

9 minutes ago, DAL59 said:

You cannot actually find life though unless you land.  

Let me make this explicitly clear in multiple ways.

First, finding life is not the only reason for planetary science. It's just the flashiest. There is a tremendous amount to be learned by studying Europa that has nothing to do about whether or not it has life.

Second, the chance of life on Europa is utterly miniscule. The planet's bombarded with radiation, and it's hard to see how fragile early life could have formed without immediately getting blasted to pieces by high-energy radiation from Jupiter.

Third, if there is life, it won't be on Europa's surface: it will be deep, deep, deep inside in the hypothesized sub-surface ocean.

Fourth, it is not a strict requirement to land to detect life. Methinks you could detect life on Earth from orbit perfectly well. The signs would be much more subtle for the hypothesized and likely microbial life on Europa, but scientists have plenty of experience establishing that certain things they can't see exist.

Fifth, we still don't know some very vital things about Europa to support such a landing. How thick the crustal ice is, where good landing sites are, etc. If it's deemed worthwhile to have a followup lander, it will benefit hugely from data from the Europa Clipper.

[Green Baron]

4 hours ago, PB666 said:

Solar power is eff. k_insolance/d² were in sol distance units its 1400 w/m² / 5.2² = 51.77 x 0.4 (very optimistic efficiency) = 20.8 w/m²

 

*giggle*

is that k insolence, insulance, insulation, insolation or isolation ?

Sorry, ignore me ...

But an ion driven probe couldn't land on Europa because thrust .... you'd need something chemical and schlepp something with the dV into Europa orbit isn't easy. Possible with current tech ?

Edit: Probably not. Let's leave something for the future ;-)

Edited March 4, 2018 by Green Baron

[_Augustus_]

10 hours ago, DDE said:

*ponders a Curiosity-style skyhook carrying a CASABA-HOWITZER charge to blast through the ice*

This makes me wonder.

Could you penetrate Europa's crust with a large tactical weapon? If so, how big? MOAB? Low-yield nuke? 

[Canopus]

15 minutes ago, _Augustus_ said:

This makes me wonder.

Could you penetrate Europa's crust with a large tactical weapon? If so, how big? MOAB? Low-yield nuke? 

Isn‘t the crust something like 20 kilometers thick? 

[Green Baron]

Well, one would rather want as little intrusion as possible if one far day one would want to have a look. A weapon is totally contradictory to that, a nuclear one even more with all its fallout and mixing up of eventually interesting samples and localities. You will not get much information, except that you made a hole.

Could be more than 20 km, these here estimate 28: https://www.sciencedirect.com/science/article/pii/S0019103515000688

The exact energy balance of Europa and its composition isn't known exactly, so models and assumptions must serve for now.

Edited March 4, 2018 by Green Baron

[PB666]

1 hour ago, Green Baron said:

*giggle*

is that k insolence, insulance, insulation, insolation or isolation ?

Sorry, ignore me ...

But an ion driven probe couldn't land on Europa because thrust .... you'd need something chemical and schlepp something with the dV into Europa orbit isn't easy. Possible with current tech ?

Edit: Probably not. Let's leave something for the future ;-)

yeah insolance is confusing. It is used in some publications {just like our friend pilt-down man] 

That's right, you could theoretically carry the lander to Europe on an ION drive space craft, this consists of two parts.

1. Hohmann transfer from LEO . . .completely plausible that you could get into the outer solar system with little fuel. The problem of course is what kind of power or weight are you going to have to add to power the ION drives. Right now typical is around 25 kg/kw of power of panel (better than the power trusses of ISS, somewhat less than the highest performance systems).
2. Jovian insertion. You could begin to circularize that orbit with solar panels before reaching the jovian, you already have the momentum, so some circularization around the asteroid belt could occur that would alter the jovian entry speed, but then once you are barreling toward Jupiter, the thing you want to do first is get as close as jupiter as possible to do the first set of burns. A chemical rocket, dispite low ISP is going to have more effect than an ION drive working way out of the jovian system trying to diminish the relative velocity. Once you are in the jovian system you can on the next apogee alter the trajectory.

Basically, if you had an ION drive system, with the exception of steering thrusters, you want to loose that system around the asteroid belt with a best effort to circularize the orbit, but that added weight is going to kill you on jovian insertion.

IN THEORY, not possible with current tech, you could have a [future power system] and ION drive that could truck any amount of any kind of fuel you want to LEurO and then that ship could land. How it could be done is that you leave Earth on a trajectory that does not intercept Jupiter. As it approaches Jupiter if corrects it velocity to match that of Jupiters orbit about the sun, but at a slightly lower orbit, As jupiter passes it then tangents outside of Europa's orbit, as it then retroburns the orbit then tangents Europa's orbit but at a semi-major axis very close to the semimajor axis of Europas orbit. Eventually the two bodies will intercept, as this orbit occurs it retros into the moons gravitational sphere of influence, and then shrinks the orbit. At which point the lander is detached and then powers its way down to the planets surface.

With infinite source of power anything is possible, but with infinite power also come infinite heat at (1-eff)*power. We know the ION drives waste about 20% heat, some of that is carried in the thrust, so you quickly get to a point with ION drive system that just the waste heat itself is too large to deal with (i.e. you could never land like ST Voyager does). So landing . . . . .impossible on a moon or planet sized object. On an asteroid or comet, ION may be preferential to other thrust systems because of the scalability of thrust.

The best modern case scenario is an efficient light weight hydrolox rocket whereby the H2 tanks are shed upon landing. The O2 remains and keroLox or Metholox are used (if possible in the same rocket -> metholox) to launch from the moon, in that case, lets pretend its a sample return mission, it then reaches orbit, in marries to the interplanetary ION drive system which then carries the lander back and corrects orbit as it approches Earth. The lander then re-enters Earths atmosphere or the ION drive goes to ISS or DSG to deliver samples. This is a carried system with several 10kw fission reactors and extremely efficient drives. Hydrogen is scavenged and kept liquefied under pressure until arrival. This is pushing all modern technologies and upgrading performance of several existing systems. There is an assumption that fission radiation will not destroy the mission.

 

[Starman4308]

44 minutes ago, Green Baron said:

The exact energy balance of Europa and its composition isn't known exactly, so models and assumptions must serve for now.

Thus the Clipper. If we can find a thin spot, it may not be too ridiculous to drill down into Europa's subsurface ocean. If it's hundreds of kilometers thick, good luck. If you see signs protesting that the Earth Clipper doesn't have a lander, it's time to get some sleep.

[PB666]

2 hours ago, Starman4308 said:

Thus the Clipper. If we can find a thin spot, it may not be too ridiculous to drill down into Europa's subsurface ocean. If it's hundreds of kilometers thick, good luck. If you see signs protesting that the Earth Clipper doesn't have a lander, it's time to get some sleep.

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

https://en.wikipedia.org/wiki/Ambient_ionization#Laser_assisted

If you are doing inorganic chemistry this will suffice. 
You can use IR lasers to prep an area of the surface (remove the volatiles)
and then hit them with a rubidium lasers allowing the vaporization of metals.

To collect and bring back life. You can't do DNA sequence analysis from a distance.  

BTW, if you had a fission reactor on-board its possible, using lasers, to burn a hole over a liquified body of water. Drop a nuclear warhead (with a very spikey nose cone) into the body, detonate it and collect the aerosol that makes in into orbit, if there is life you would find it there. Of course past (pre-nuclear) performance of life is no indicator of future success.

 

 

 

 

[sevenperforce]

ISS question, since this is the NASA thread...

I've started a save where I'm building and playing through every orbital launch worldwide:

So far I've done an Atlas V, a Falcon 9, and a Soyuz-FG (though it's not due to upload until Friday).

But we will have a Soyuz flight to the ISS later this month, so I need to put an ISS clone into orbit so it has a destination. 

I'm having trouble finding sufficiently detailed ISS schematics to actually build an ISS clone in the spaceplane hangar (though I'll be putting it into orbit with F12). Any tips? How would you design an ISS clone in KSP? The only mod I'm using is Tweakscale.

[tater]

Ugh. Dunno, I'd have suggestions, but I don't use stock much. Instead of tweakscale, I'd suggest SSTU. You'd get R-7 stuff, and russian and US station parts as well (though no SpaceX stuff yet, aside from engines).

[PB666]

4 hours ago, tater said:

Ugh. Dunno, I'd have suggestions, but I don't use stock much. Instead of tweakscale, I'd suggest SSTU. You'd get R-7 stuff, and russian and US station parts as well (though no SpaceX stuff yet, aside from engines).

I just mod the stock stuff with RL stats. The exception is the RL10b variants (cause the game version looks nothing like an RL10b. What kills however is that tank masses in game are rediculously high. The STS ET had a 4% tank mass to fuel ratio and that was a liquid hydrogen tank, but on the other hand I just launched 55 kt of rocket tonight and put 3300 kt in LEO shooting 800 kt of metal into transmartian orbit. I bet I can make a crater on any upstart colony with that, lol.

[NSEP]

On 04/03/2018 at 6:35 PM, Starman4308 said:

The planet's bombarded with radiation, and it's hard to see how fragile early life could have formed without immediately getting blasted to pieces by high-energy radiation from Jupiter

Europa is shielded by litterly 30 kilometers of Ice, and hundreds of miles of water, i doubt radiation would be a problem for life there.

Im not saying Europa has a likely chance of life though, the pressure down there in the surface is 8000x ASL pressure, (correct me if im wrong) Enceladus is way more mundane, and something we can actually explore.

Im geussing you are talking about The Ionized Radation Baked Cupcake Europa Clipper? Im a little dissapointed they ditched the lander, but oh well.

 

Edited March 7, 2018 by NSEP

[Canopus]

1 hour ago, NSEP said:

Im a little dissapointed they ditched the lander, but oh well.

 

The lander was removed very early on but wasn‘t cancelled i think. Just moved to a seperate launcher at a later date.

[Starman4308]

I recently read an article saying that the Starliner's thrusters have just arrived: am I correct in guessing that these are RCS thrusters for the reentry module, and are mostly intended for attitude control during reentry?

http://www.spaceflightinsider.com/organizations/aerojet-rocketdyne/cst-100-starliner-reentry-thrusters-delivered/

It's a dozen MR-104J engines, each of which burns hydrazine producing 440N of thrust; small satellites might use such an engine as their main thruster, whereas for Orion, it's attitude-control thrusters. Probably the biggest use during reentry would be to keep the roll aligned for a lifting reentry.