To that end, going to the Moon is very logical. We're finally going to learn how to live away from Earth. If we go to Mars a few times, never to return, whats the point?
Also, a lunar base can be mothballed more easily than ISS. In times of an economic downturn, you can stop going to the lunar base for a few years. If you stop going to ISS for a few years, it crashes back to Earth.
There are two primary types of nuclear fission propulsion being researched
NEP - Nuclear Electric Propulsion
The use of a nuclear reactor to provide electricity to ion thrusters, instead of Solar arrays like Deep-Space 1. This is the kind of propulsion being planned for JIMO. Low thrust, very high effiency (exhaust velocity)
NTP - Nuclear Thermal Propulsion
Take a nuclear reactor, pump hydrogen through it with a turbopump, hydrogen expands, and produces thrust when forced through a nozzle.
This kind of propulsion has much higher thrust than NEP, but it less efficient (still about twice as efficient as LOX/LH2 chemical propulsion though. This can produce enough thrust for launch.
But by 6:15 a.m. (1:15 a.m. EST) the rocket passed out of the potential signal range without hearing anything.
The orbiters are slightly more advanced than a mere rocket. I wish the press would stop dumbing things down, I would think the majority of their audience graduated grade school.
as you move to higher and higher powers, nuclear reactors become more and more cost effective, since theres a large upfront mass penantly, but additional kilowatts of output dont cost as much (diminising returns)
For any heavenly body with a satellite in a relatively circular orbit, there are 5 points where gravitational forces and centripetal accelerations cancel each other out. Three fall on a line that connects the two bodies, and the other form a pair of equilateral triangles with the heavenly bodies.
L1 between the two bodies L2 on the far side of the smaller body L3 on the far side of the larger body L4 is the "leading" equilateral point L5 is the "trailing" equilateral point
L4 and L5 are relatively stable. Putting a station at L1-3 would require more propellant to keep it there, though not an unreasonable amount.
Personally, I'd rather go for a base on the Moon that at a libration point. Sure, it requires more propellant to get to and from there, but its also a permanent fixture, rather than something that would need to be disposed of eventually.
Except that the xprize contenders are suborbital. They cant reach ISS, and I doubt any of them could be upgraded to do so, within the safety metrics of NASA, for much less than the cost of OSP.
The opening has a magnetized torid ring around it. Using the right hand rule (make a fist, stick your thumb out like you are hitchhiking...your thumb is the direction of the electric current, your fingers are curled in the direction of magnetic field flow) you create an electrical flow around the metal torid ring. The resulting magnetic field 'pulls' the ions through the ring, resulting in propulsion.
Actually, what you describe there sounds like a Hall effect thruster. Not all ion drives are Hall thrusters.
DS1's ion engine used charged grids rather than a metal toroid to achieve the acceleration of the ions.
In addition to Hall effect thrusters and grid-based ion engines, there are also arcjets, resistojets, and the ever-sexy-but-a-few-years-off magneto-plasma-dynamic thrusters.
Deep space one and many communications satellites already use them.
They dont really make sense as backup as you have to have two completely separate systems to support them (propellant feed, power, etc). Thats a lot of mass for something that may be nothing more than backup.
They make perfect sense for unmanned missions. Theres typically no hurry to get where youre going, and the mass benefits are large.
They can be used on manned missions, the crew would simply rendezvous with the craft in high Earth orbit rather than being aboard for the entire escape spiral from Earth.
Smart is solar powered, and likely on the order of 1's or 10's of kilowatts.
Once you start tying ion propulsion to a nuclear power source, you start being able to achieve higher thrust levels. SMART only uses a little over 1kW of power.
Its very practical. Ion propulsion can take longer than chemical (although this is not always the case) but it has a much higher specific impulse, and therefore a much lower propellant mass fraction. That means you can get more mass to a destination given the same launch mass, or, take the same payload and use a much smaller (cheaper) launch vehicle.
Worksheet functions are great, but a lot of Excel's draw comes from its embedded VBA. Companies that rely on workbooks with embedded VBA probably wont be willing to switch to Gnumeric until it has support for VBA, or something very similar.
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To that end, going to the Moon is very logical. We're finally going to learn how to live away from Earth. If we go to Mars a few times, never to return, whats the point?
Also, a lunar base can be mothballed more easily than ISS. In times of an economic downturn, you can stop going to the lunar base for a few years. If you stop going to ISS for a few years, it crashes back to Earth.
Are they using 1.1 inch margins and 1.5x line spacing too?
Just to educate the willing...
There are two primary types of nuclear fission propulsion being researched
NEP - Nuclear Electric Propulsion
The use of a nuclear reactor to provide electricity to ion thrusters, instead of Solar arrays like Deep-Space 1. This is the kind of propulsion being planned for JIMO. Low thrust, very high effiency (exhaust velocity)
NTP - Nuclear Thermal Propulsion
Take a nuclear reactor, pump hydrogen through it with a turbopump, hydrogen expands, and produces thrust when forced through a nozzle.
This kind of propulsion has much higher thrust than NEP, but it less efficient (still about twice as efficient as LOX/LH2 chemical propulsion though. This can produce enough thrust for launch.
IAARS, FWIW
Feh. The moon is useful in the short term. Mars would just be a "woohoo we did it" trip.
While exceedingly cool and awe inspriring, the moon is a necessary base for human space exploration.
I'd agree. It has its problems, but its the most fun I've ever had in a computer game.
But by 6:15 a.m. (1:15 a.m. EST) the rocket passed out of the potential signal range without hearing anything.
The orbiters are slightly more advanced than a mere rocket. I wish the press would stop dumbing things down, I would think the majority of their audience graduated grade school.
mass is still important, since it requires propellant to accelerate
as you move to higher and higher powers, nuclear reactors become more and more cost effective, since theres a large upfront mass penantly, but additional kilowatts of output dont cost as much (diminising returns)
Correct :)
The first says "I'll have a martini"
The second says "Darn I wanted a Martini too"
- Credit my E&M Prof.
AKA Libration Points...
For any heavenly body with a satellite in a relatively circular orbit, there are 5 points where gravitational forces and centripetal accelerations cancel each other out. Three fall on a line that connects the two bodies, and the other form a pair of equilateral triangles with the heavenly bodies.
L1 between the two bodies
L2 on the far side of the smaller body
L3 on the far side of the larger body
L4 is the "leading" equilateral point
L5 is the "trailing" equilateral point
L4 and L5 are relatively stable. Putting a station at L1-3 would require more propellant to keep it there, though not an unreasonable amount.
Personally, I'd rather go for a base on the Moon that at a libration point. Sure, it requires more propellant to get to and from there, but its also a permanent fixture, rather than something that would need to be disposed of eventually.
Except that the xprize contenders are suborbital. They cant reach ISS, and I doubt any of them could be upgraded to do so, within the safety metrics of NASA, for much less than the cost of OSP.
Hope they have lots of backup. Of course, how do you backup a system like this?
remember kids, always preview your post before submitting
The opening has a magnetized torid ring around it. Using the right hand rule (make a fist, stick your thumb out like you are hitchhiking...your thumb is the direction of the electric current, your fingers are curled in the direction of magnetic field flow) you create an electrical flow around the metal torid ring. The resulting magnetic field 'pulls' the ions through the ring, resulting in propulsion.
Actually, what you describe there sounds like a Hall effect thruster. Not all ion drives are Hall thrusters.
DS1's ion engine used charged grids rather than a metal toroid to achieve the acceleration of the ions.
In addition to Hall effect thrusters and grid-based ion engines, there are also arcjets, resistojets, and the ever-sexy-but-a-few-years-off magneto-plasma-dynamic thrusters.
Deep space one and many communications satellites already use them.
They dont really make sense as backup as you have to have two completely separate systems to support them (propellant feed, power, etc). Thats a lot of mass for something that may be nothing more than backup.
They make perfect sense for unmanned missions. Theres typically no hurry to get where youre going, and the mass benefits are large.
They can be used on manned missions, the crew would simply rendezvous with the craft in high Earth orbit rather than being aboard for the entire escape spiral from Earth.
Smart is solar powered, and likely on the order of 1's or 10's of kilowatts.
Once you start tying ion propulsion to a nuclear power source, you start being able to achieve higher thrust levels. SMART only uses a little over 1kW of power.
Its very practical.
Ion propulsion can take longer than chemical (although this is not always the case) but it has a much higher specific impulse, and therefore a much lower propellant mass fraction. That means you can get more mass to a destination given the same launch mass, or, take the same payload and use a much smaller (cheaper) launch vehicle.
Genesis uses chemical propulsion
The upcoming Dawn mission will also utilize ion propulsion.
But there is also fortran 90, 95, and the new 2000 spec.
A bare chassis with a 500hp engine.
NASA Glenn Research Center (formerly Lewis Research Center) is located in Cleveland, which undoubtedly is one of the reasons for his co-sponsorship.
Just the same, I think its a fantastic idea. We need a new technological goal in this country.
Worksheet functions are great, but a lot of Excel's draw comes from its embedded VBA. Companies that rely on workbooks with embedded VBA probably wont be willing to switch to Gnumeric until it has support for VBA, or something very similar.
Point taken. But I dont get any stuttering even when billions of polygons are being rendered.
The framerates are awesome!
I'm all in favor of paying the artist. But I think technology is at the point where the middleman (record labels) is irrelevant.