Oddly I was just thinking about this last night. Men tend to like colors at the blue end of the spectrum. Women like the red end of the spectrum. The orange/brown scheme for ubuntu may be more attractive for much of the general population, while mostly male geeks dislike it.
For me, I just select a different theme and put on my own background image. Most of us have a few thousand of those sitting around these days.
Since it will accelerate all the way to orbit there shouldn't be a problem getting fuel out of the tanks. For burns in orbit a hydrazine based reaction control system should be sufficient.
Liquid oxygen is as compact as oxygen can be made. For fuel, kerosene is more compact than hydrogen.
I don't see an issue with guidance. An iPhone will do a pretty good job of it in this day and age.
BTW I don't think this space plane thing will work but I do think the engines would be great for a high speed military vehicle. Something to get a payload to the target really fast. It could do unpowered semi ballistic lobs as well.
If you stay low to scoop more oxygen from the air then you waste fuel fighting drag. In practice it is best to get above the atmosphere as fast as possible.
The best possible case is that it might be able to use air at mach 7. That is one third of orbital velocity. I don't think the word "eventually" is appropriate in this context. In practice I doubt this engine can be an air breather anywhere near that speed.
...to save a few hundred kilos of oxidiser. On the ground they won't be moving fast enough to scoop oxygen out of the air. In less than a minute they will be too high and fast to use anything from the atmosphere. Once effectively out of the atmosphere most of the work remains to be done so that will have to use stored oxygen.
The only type of space based power I can see happening in the next 50 years is to reflect sunlight onto ground based solar power stations with orbiting mirrors. Traditional SPS is too far away. We can't even keep the systems on the ISS working between shuttle flights.
I seem to remember that (maybe prompted by the Sealand debate), the UN changed the rules so that any artifical island cannot qualify for statehood, (even if it's outside territorial waters).
So what is an artificial island? People in my country live in artificial structures on solid land. Sealand in an artificial structure on solid sea floor. What about a country in the pacific which gets drowned by rising sea levels? Do they lose nationhood even if they build up their island with buildings and North American trash?
My wife had this PC with an oldish power supply which had a power output so you could power other devices like a monitor. Years ago I built a power board so I could use the PC to switch on speakers, lamp, printer etc. All low power stuff. One cold day she plugged a 2400 watt fan heater into that power board....
No more power supply after that though the rest of the system was okay.
This reminds me of the Apple ][ in school. Apple had a huge education discount back then. In hopes that kids will grow up with the Apple ][ and Macs and then will purchase them when they grow up.
We had Apple ]['s at high school. They were fantastic machines. very easy to hack and develop for. The transition to the Mac turned me away from Apple. It was less open, more oriented to non-technical users.
Result, more orbiting fragments (albeit smaller ones).
If the object you send to collide with the dangerous debris is not in orbit before the collision then it can't be in orbit after the collision. I think a cloud of gas might do the trick, deployed from a sounding rocket, fired straight up from the ground.
All you really have to do is steal a fraction of the momentum of the orbiting fragment, then it will deorbit. I think pretty much any collision will do that.
The objects we want to take out of orbit are in a stable trajectory. If they collide with an object fired directly from the ground they will lose some velocity and move into a lower orbit. Low altitude orbits decay quickly because of drag from the atmosphere so these objects will quickly burn up.
The object you fire from the ground to cause a collision will be shoved sideways a short distance. It can't go into orbit.
Having thought about it for a bit I think the best thing to send up in the sounding rocket is a bottle of liquid nitrogen. It will form an expanding cloud at orbital altitude. Debris which fly through the cloud will lose some speed and their orbits will decay. Sounding rocket firings could be timed to minimise impact on operational spacecraft.
My thought is to fire a sounding rocket directly into the path of the debris. At the peak altitude the rocket explodes, releasing something like strips of foil which will collide with orbiting debris. Given time, it should be possible to clean up these orbits.
An orbiter is nice but getting down to the surface and exploring on Europa its self is I believe, infinitely more informative than setting up shop in orbit. After all, the data we have on the moon suggests that it has an extensive conductive salty ocean underneath its surface that may have life swimming around vents that could exist in that ocean's floor like Earth.
Nobody really knows how to get to the ocean. It is certain to be many kilometers down. Having said that some seismic data would be handy. Its a pity we can't drop a simple lander on this trip with an impactor to generate a signal. Maybe an accurate laser altimeter would tell us about the interior?
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But the brown color scheme sucks.
Oddly I was just thinking about this last night. Men tend to like colors at the blue end of the spectrum. Women like the red end of the spectrum. The orange/brown scheme for ubuntu may be more attractive for much of the general population, while mostly male geeks dislike it.
For me, I just select a different theme and put on my own background image. Most of us have a few thousand of those sitting around these days.
Yes I had the thought that we should be using eucalyptus oil as biofuel. There certainly is a lot of the stuff around.
I think it is a way to develop an unmanned hypersonic bomber, without owning up to the fact for most of the development cycle.
Since it will accelerate all the way to orbit there shouldn't be a problem getting fuel out of the tanks. For burns in orbit a hydrazine based reaction control system should be sufficient.
Liquid oxygen is as compact as oxygen can be made. For fuel, kerosene is more compact than hydrogen.
I don't see an issue with guidance. An iPhone will do a pretty good job of it in this day and age.
BTW I don't think this space plane thing will work but I do think the engines would be great for a high speed military vehicle. Something to get a payload to the target really fast. It could do unpowered semi ballistic lobs as well.
If you stay low to scoop more oxygen from the air then you waste fuel fighting drag. In practice it is best to get above the atmosphere as fast as possible.
the engine eventually switches to a pure rocket
The best possible case is that it might be able to use air at mach 7. That is one third of orbital velocity. I don't think the word "eventually" is appropriate in this context. In practice I doubt this engine can be an air breather anywhere near that speed.
..That someone built a spaceplane.
We have a space plane.
(to go with our Horseless Carriages and Digital Cameras.)
I think the only ones who do this stuff successfully are the Americans.
An Australian team has flown a scramjet.
...to save a few hundred kilos of oxidiser. On the ground they won't be moving fast enough to scoop oxygen out of the air. In less than a minute they will be too high and fast to use anything from the atmosphere. Once effectively out of the atmosphere most of the work remains to be done so that will have to use stored oxygen.
The only type of space based power I can see happening in the next 50 years is to reflect sunlight onto ground based solar power stations with orbiting mirrors. Traditional SPS is too far away. We can't even keep the systems on the ISS working between shuttle flights.
Yeah but then the data haven actually belongs to the Sultan.
I seem to remember that (maybe prompted by the Sealand debate), the UN changed the rules so that any artifical island cannot qualify for statehood, (even if it's outside territorial waters).
So what is an artificial island? People in my country live in artificial structures on solid land. Sealand in an artificial structure on solid sea floor. What about a country in the pacific which gets drowned by rising sea levels? Do they lose nationhood even if they build up their island with buildings and North American trash?
Steal an ICBM, buy an oil rig, and THEN claim you're an independant nation and you might have a better case for nation status.
As an Australian I believe you shouldn't be a nation unless you are surrounded by water. That would certainly save on seats in the UN.
Yeah, TPB wanted to buy it, but Sealand was asking for a fortune.
They could just buy an old freighter and park it somewhere in international waters.
My wife had this PC with an oldish power supply which had a power output so you could power other devices like a monitor. Years ago I built a power board so I could use the PC to switch on speakers, lamp, printer etc. All low power stuff. One cold day she plugged a 2400 watt fan heater into that power board....
No more power supply after that though the rest of the system was okay.
I had a lot of fun with my 6502 copying the BASIC interpreter into the video RAM then bubble sorting it with a little bit of machine code.
This reminds me of the Apple ][ in school. Apple had a huge education discount back then. In hopes that kids will grow up with the Apple ][ and Macs and then will purchase them when they grow up.
We had Apple ]['s at high school. They were fantastic machines. very easy to hack and develop for. The transition to the Mac turned me away from Apple. It was less open, more oriented to non-technical users.
;)
Maybe they should have put Woz in charge
Liquid argon.
What properties of argon are you thinking of?
Result, more orbiting fragments (albeit smaller ones).
If the object you send to collide with the dangerous debris is not in orbit before the collision then it can't be in orbit after the collision. I think a cloud of gas might do the trick, deployed from a sounding rocket, fired straight up from the ground.
All you really have to do is steal a fraction of the momentum of the orbiting fragment, then it will deorbit. I think pretty much any collision will do that.
The objects we want to take out of orbit are in a stable trajectory. If they collide with an object fired directly from the ground they will lose some velocity and move into a lower orbit. Low altitude orbits decay quickly because of drag from the atmosphere so these objects will quickly burn up.
The object you fire from the ground to cause a collision will be shoved sideways a short distance. It can't go into orbit.
Having thought about it for a bit I think the best thing to send up in the sounding rocket is a bottle of liquid nitrogen. It will form an expanding cloud at orbital altitude. Debris which fly through the cloud will lose some speed and their orbits will decay. Sounding rocket firings could be timed to minimise impact on operational spacecraft.
My thought is to fire a sounding rocket directly into the path of the debris. At the peak altitude the rocket explodes, releasing something like strips of foil which will collide with orbiting debris. Given time, it should be possible to clean up these orbits.
How could they pick this really unimpressive Europa mission over that? Aaargh!
The Titan mission looks very risky to me. I think that might have been a factor.
There have been proposals
Yeah I know but I think they base their assumptions on Arthur C Clarke books rather than the few facts we know about Europa.
An orbiter is nice but getting down to the surface and exploring on Europa its self is I believe, infinitely more informative than setting up shop in orbit. After all, the data we have on the moon suggests that it has an extensive conductive salty ocean underneath its surface that may have life swimming around vents that could exist in that ocean's floor like Earth.
Nobody really knows how to get to the ocean. It is certain to be many kilometers down. Having said that some seismic data would be handy. Its a pity we can't drop a simple lander on this trip with an impactor to generate a signal. Maybe an accurate laser altimeter would tell us about the interior?