Nefrums
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Posts posted by Nefrums
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12 minutes ago, CatastrophicFailure said:
I'm not sure where you're getting that "3" number, Soyuz 10a (crew of 2) was directly saved by their LES.
I mean people killed because there was a LES.
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Why are LES required anyway? The shuttle did for obvious reasons not have LES. And the total lives saved by LES through out history is -1 (2 saved and 3 killed).
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4 hours ago, sevenperforce said:
Wow, impressive.
Currently, the rules only allow 5 launches from Kerbin, so that's something to consider.I made a penalty allowance for mission profiles requiring more than five launches.Fortunately I will not launch any ship from Kerbin, as I use RSS.
I started designing this mission well before this change, with the goal of making a Mars mission as realistic and as low cost as possible.
I also brake other rules of this challenge, my ksp installera take like 3-4 min to start, and it is not due to a slow computer.
I have based much of my mission on the NASA Mars plans. I use life support configs to match the mass estimate of food etc from the NASA plans.
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21 hours ago, sevenperforce said:
What a surprise!
Well, maybe the relaxed requirements of this mission will be more achievable. I'd love to see your mission architecture!
Basic architecture:
Only chemical engins, no isru. 4 kerbal mission.
Use the same launcher for everything, loosely based on a real launcher that is about to fly.
~40t to LEO.
First send 4-5 unnamed supply missions that put about 10t each on Mars surface.
Then construct transfer habitat in LEO with the following launches:
1 transfer habitat.
1 MAV with hypergolic fuel
2 return trip boosters. Also hypergolic.
7-8 methane + lox fuel for the outbound trip.
180 days outbound ~2 year stay and 180 days back.
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I have actually ben trying to do a mission like this, but trying to make it as realistic as possible. RSS, Life support, fuel boil-of, using the same launcher for everything etc.
It is turning out to be really really hard to design a realistic mars mission.
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You might want to disallow using tweak scale to make crewed parts smaller.
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Quote
If the hurricane does track into Florida, SpaceX and NASA could have bigger problems on its hands. Cape Canaveral is basically built on a large sandbar and the high winds and tidal surges a mega-storm produces could damage the facility.
Since Hurricane Andrew in 1992, all new buildings at the location have been built to withstand wind speeds of up to 130mph. However, Irma is, right now, producing winds in excess of 180mph and may pick up more strength before it hits the coast.
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11 hours ago, CatastrophicFailure said:
On a related note, I see SES-11 delayed till October.
Any details on why?
So they have time to repair the pad and build a new VAB after the old one blew away?
Edit: Seriously thou, Irma has the potential to cause serous damage to KSC. Lets hope it does not as that could be very bad for spaceX
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The question here is how much fuel can you add before twr gets so low that you get no benefit of adding more fuel.
As dry mass ratios of fuel tanks is very different irl and in game and the cost of adding more fuel is very low. This tends to end up with a liftoff twr around 1,2 irl.
The main thing that is optimized irl is payload/cost. Amount of dV spent to get to orbit is irelevant.
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This sounded fun!
Here is my attempt:
10 parts, 5,91 tons, 6m tall and 5428
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1 hour ago, Nefrums said:
NASA's budget is about 200% larger than ESAs.
1 hour ago, tater said:The NASA budget is 19.5 B$. ESA is ~6.8 B$, so more like 1/3 of NASA's.
Yes those two are very different....
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Yes. It would be great if ESA could get the same budget share as NASA does, and even that is not that large nowadays.
While the GDP of US is ~10% larger than EU, NASA's budget is about 200% larger than ESAs.
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5 hours ago, sevenperforce said:
What nonsense. It's not SpaceX's choice; it's federal law.
This!
Elon has himself said that spaceX will start hiring non americans as soon as the US law allows them to do so. (Q&A section of the ITS presentation, if my memory serves me right)
It was something to do with that rocket science counts as weapons research in the US.
Tesla on the other hand has no problems with hiring foreign workers.
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33 minutes ago, IncongruousGoat said:
I highly doubt SpaceX is going to go for second-stage reuse with the Falcon family. It makes much more sense for them to go for it with mini-ITS, since there second-stage reuse is an integral part of the design. Whether they'll succeed is a whole nother matter entirely...
This is exactly the reason that i believe that they will try to make the second stage of falcon reusable. To be able to develop and test the technology on "free" launches.
It will cut into the payload, so it will not be used on all missions, just like the first stage is not reusable for all missions.
I also believe that they will use the vacuum optimized engine for the landings, the ISP will not be good, but the twr on a almost empty second stage should not be a problem.
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20 minutes ago, wumpus said:
Are the boosters that use three engines useable? Those burns cut the landing time by a lot (I don't think a single engine can get a TWR>2, so gravity losses add up). Not sure if they need fuel in separate tanks for side engine cutoff or simply use the main tank (obviously they need some reserves to avoid fuel-out, landing with separate fuel reserves would hurt dry mass).
A single engine gets a twr of ~4 when dry, (no fuel left).
Looking at the videos the first stage appears to be in the transonic region when the landing burn starts. And as the landing burn lasts for about 30s, so it appear to be about twr 2.
It would not be a good idea to make the landing burn shorter as the first stage needs to change course. Before the landing burn starts it is on a ballistic trajectory into the sea. So it won't do damage in case of engine faliure.
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Earth is 10 times bigger than Kerbin. (radius) and is 100 times heavier.
(You would think that the mass of Earth would be 1000 larger as the volume, but apparently Kerbin is made up of something twice as heavy as the heaviest material IRL )
If we do like in the game approximate the gravity to all be in a point at the center of the planet Earth have a 100 times greater gravity then Kerbin. The surface gravity is the same as the Earths surface is 10 times farther from the center then Kerbins surface. (gravity decreases with r^2)
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From their vids it looks like they are making the combustion chamber of the engine out of fiberglass...
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It is a bit strange that they plan to do a scaled down suborbital launch next month. And from what I can tell that is before any ground tests of the engine.
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What types of payloads that are possible depend heavily on the prize tag.
When the launch cost have dropped an order of magnitude, space tourism will kick off for real. Probably ~10-20 years from now. Tourism is a trillion $ industry.
When the launch cost drop anoder order of magnitude space mining becomes viable, etc.
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7 hours ago, Xeldrak said:
@Nefrums Nicely done! However, if you want to see your name on the coveted leaderboard I need you to calculate your score
ok, (is there a RSS leader board?
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3-man Mission +10
- 2-man Lander +10
- 2-stage Lander (leave the decent-engine on the Mun) +20
- Launch escape system in place? +10
- Lander stored behind the CM during ascent +20
- Lander tucked away behind some kind of fairing? +5
- Flawless landing (no parts broke off, Neil Armstrong is watching you!) +10
- After succesfull Mun landing dock CM and MM in munar orbit (no swapping ships without docking them first) +10
- Plant flag on the Mun (no cumulative, i.e. two flags don't get you 6 points) +3
- Spashing down on Kerbin (land on water) +5
103p.
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Here is my recreation of Apollo 11 in RSS:
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I couldn't resist recreating this mission as close as i could to the real thing:
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Orion flew to 5800km above earth. As kerbin is 1/10th scale of Earth. It would be closer to scale if the target was 580km above kerbin.
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I highly doubt that it would be possible to reenter the second stage top first. All the mass is at the bottom. It would be very aerodynamically unstable.
It would require huge fins, mounted behind CoM, And CoM for an empty stage is probably not that far above the engine.
~40t to LEO.
Any details on why?
SpaceX Discussion Thread
in Science & Spaceflight
Posted
https://en.wikipedia.org/wiki/Soyuz_7K-OK_No.1