Mars in 39 days
Discussion
spikeyhead said:
I'd like to know just how different this engine is from this
To QuotE QinetiQ:'
T5 ion thruster ..........
The core system comprises the QinetiQ T5 gridded ion engines, Astrium Crisa Ion Propulsion Control Units (IPCU) and Bradford Engineering Proportional Xenon Feed Assembly (PXFA). It offers:
Reliable, efficient and robust system configuration
Unprecedented thrust range (1 - 20 mN)
Ultra precise thrust control (+/- 12 microN)
Rapid thrust response rate (> 2.5 mN / s)
Total impulse up to 3 x 10E+6 Ns (1.5 x 10E+6 Ns in GOCE conditions)
Cycle life > 5500 On/Off cycles
Cyclic & continuous operation
Modular and adaptable system architecture.......'
Do they do a crate version that I can shoe-horn into my M chassis?!
KANEIT said:
spikeyhead said:
I'd like to know just how different this engine is from this
To QuotE QinetiQ:'
T5 ion thruster ..........
The core system comprises the QinetiQ T5 gridded ion engines, Astrium Crisa Ion Propulsion Control Units (IPCU) and Bradford Engineering Proportional Xenon Feed Assembly (PXFA). It offers:
Reliable, efficient and robust system configuration
Unprecedented thrust range (1 - 20 mN)
Ultra precise thrust control (+/- 12 microN)
Rapid thrust response rate (> 2.5 mN / s)
Total impulse up to 3 x 10E+6 Ns (1.5 x 10E+6 Ns in GOCE conditions)
Cycle life > 5500 On/Off cycles
Cyclic & continuous operation
Modular and adaptable system architecture.......'
Do they do a crate version that I can shoe-horn into my M chassis?!
Edited by s2art on Wednesday 6th August 19:55
s2art said:
spikeyhead said:
I'd like to know just how different this engine is from this
How about a gazillion times more thrust and needs a multi-gigawatt nuclear reactor to power it?Warning – geeky stuff follows!
XIPS systems like the QinetiQ ion thrusters are very low ISP, but low mass. They are typically used on communication satellites for station keeping or for deep space missions where large dV's (change in velocity) are needed but time is less critical. XIPS systems can burn for months to produce the same effect that a conventional rocket engine could produce in minutes. The advantage is the lower weight.
VASMIR is, IMHO, not practical, and I have no idea where Administrator Griffin (must admit I am not his biggest fan) got the idea of flying on the ISS from. All shuttle missions from now to the end of the program have cargo assigned, and even if an additional mission is flown, there is far higher priority cargo - specifically ORU's (NASA-speak for spare parts - Orbital Replacement Units) and AMS2 (a science package, which is already built) to go up on it.
Logistics after shuttle, especially unpressurised cargo is still a big issue, and again spares are going to take priority. Of course, getting it uphill is the 'easy' bit of the challenge; let’s see NASA try to get additional funding for VASMIR. Additionally ISS is really the last place you want to be conducting propulsive experiments; it disturbs the microgravity environment the majority of the experiments require. A dedicated test vehicle would make far more sense, especially in terms of power availability. ISS has less free power than planned as the US section now provides power to the Russian section as well.
On the topic of VASMIR for Mars, I expect BNTR (Bimodal Thermal Nuclear Rocket) is a more realistic near term prospect. NASA have already expressed a preference for this method, and both the US and USSR played with them in the 60’s and 70’s. In very simple terms, they are quite similar to a conventional hydrogen/oxygen rocket engine. A turbo-pump (basically a turbocharger) passes liquid hydrogen into a combustion chamber. With a typical rocket, this process would be repeated with liquid oxygen and the two ignited. With a BNTR, the hydrogen is passed over a reactor core, heating the hydrogen resulting in thrust.
This is useful as only one cryogenic liquid is needed and is therefore easier to manage. The other benefit is in the bimodal part – when not used as a rocket engine, the reactor can be used to provide electrical energy. Also, a little liquid oxygen can be injected after the reactor, acting, in effect, as an afterburner.
Edited by bobthemonkey on Wednesday 6th August 20:34
s2art said:
KANEIT said:
spikeyhead said:
I'd like to know just how different this engine is from this
To QuotE QinetiQ:'
T5 ion thruster ..........
The core system comprises the QinetiQ T5 gridded ion engines, Astrium Crisa Ion Propulsion Control Units (IPCU) and Bradford Engineering Proportional Xenon Feed Assembly (PXFA). It offers:
Reliable, efficient and robust system configuration
Unprecedented thrust range (1 - 20 mN)
Ultra precise thrust control (+/- 12 microN)
Rapid thrust response rate (> 2.5 mN / s)
Total impulse up to 3 x 10E+6 Ns (1.5 x 10E+6 Ns in GOCE conditions)
Cycle life > 5500 On/Off cycles
Cyclic & continuous operation
Modular and adaptable system architecture.......'
Do they do a crate version that I can shoe-horn into my M chassis?!
Edited by s2art on Wednesday 6th August 19:55
CLK-GTR said:
s2art said:
KANEIT said:
spikeyhead said:
I'd like to know just how different this engine is from this
To QuotE QinetiQ:'
T5 ion thruster ..........
The core system comprises the QinetiQ T5 gridded ion engines, Astrium Crisa Ion Propulsion Control Units (IPCU) and Bradford Engineering Proportional Xenon Feed Assembly (PXFA). It offers:
Reliable, efficient and robust system configuration
Unprecedented thrust range (1 - 20 mN)
Ultra precise thrust control (+/- 12 microN)
Rapid thrust response rate (> 2.5 mN / s)
Total impulse up to 3 x 10E+6 Ns (1.5 x 10E+6 Ns in GOCE conditions)
Cycle life > 5500 On/Off cycles
Cyclic & continuous operation
Modular and adaptable system architecture.......'
Do they do a crate version that I can shoe-horn into my M chassis?!
Edited by s2art on Wednesday 6th August 19:55
CLK-GTR said:
s2art said:
KANEIT said:
spikeyhead said:
I'd like to know just how different this engine is from this
To QuotE QinetiQ:'
T5 ion thruster ..........
The core system comprises the QinetiQ T5 gridded ion engines, Astrium Crisa Ion Propulsion Control Units (IPCU) and Bradford Engineering Proportional Xenon Feed Assembly (PXFA). It offers:
Reliable, efficient and robust system configuration
Unprecedented thrust range (1 - 20 mN)
Ultra precise thrust control (+/- 12 microN)
Rapid thrust response rate (> 2.5 mN / s)
Total impulse up to 3 x 10E+6 Ns (1.5 x 10E+6 Ns in GOCE conditions)
Cycle life > 5500 On/Off cycles
Cyclic & continuous operation
Modular and adaptable system architecture.......'
Do they do a crate version that I can shoe-horn into my M chassis?!
Edited by s2art on Wednesday 6th August 19:55
On Earth, you'd need a rather small 'M chassis' in order to see any movement.
I thought the main attraction of plasma rockets were the much smaller amounts of propellant needed and also the fact they are electric making it possible that they can be refuelled in flight and using materials to hand in space.
The tricky bit is providing a electricity source, small nuclear reactor in space are nothing new, however, putting human in near contact with them is.
VASIMR is different because it generates much higher exhaust velocities than previous plasma rockets and higher levels of thrust providing acceleration over many months, even years, rather than chemical rockets higher levels of thrust in minutes.
As a result, velocities (delta-v) whilst at a lower level of acceleration can be much higher, often by two orders of magnitude compared to chemical rockets.
The tricky bit is providing a electricity source, small nuclear reactor in space are nothing new, however, putting human in near contact with them is.
VASIMR is different because it generates much higher exhaust velocities than previous plasma rockets and higher levels of thrust providing acceleration over many months, even years, rather than chemical rockets higher levels of thrust in minutes.
As a result, velocities (delta-v) whilst at a lower level of acceleration can be much higher, often by two orders of magnitude compared to chemical rockets.
First of all wwwwwwoooooooowwwww
Secondly, couldn't you set it up to provide a constant 1G acceleration so the crew don't turn into Chris Moyles... they'd only spend a few minutes floating at the half way point while they turn the mofo around!
Drastic oversimplification I know
Secondly, couldn't you set it up to provide a constant 1G acceleration so the crew don't turn into Chris Moyles... they'd only spend a few minutes floating at the half way point while they turn the mofo around!
Drastic oversimplification I know
OJ said:
First of all wwwwwwoooooooowwwww
Secondly, couldn't you set it up to provide a constant 1G acceleration so the crew don't turn into Chris Moyles... they'd only spend a few minutes floating at the half way point while they turn the mofo around!
Drastic oversimplification I know
Could do. Another design is a big girder, with a reactor at one end, and the crew at the other. Its spun around to create artifical gravity. The engines are mounted on a gimbal/bearing at the midpoint allowing 360 degree rotation in the opposite direction to the vehicle so the thrust in always on a constant vector. Secondly, couldn't you set it up to provide a constant 1G acceleration so the crew don't turn into Chris Moyles... they'd only spend a few minutes floating at the half way point while they turn the mofo around!
Drastic oversimplification I know
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