Has Franklin Chang Diaz asked other aerospace companies to test VASIMR? Does he have enough money to make a small spacecraft to test the VX-200?. If NASA can not give funding, I think Franklin should ask Elon Musk or ask other aerospace companies for funding e.g. ESA for funding or international funding.
As to the ESA or any other non-US government: they are generally only interested in spending money at home, where they can justify their existence by saying they are creating jobs. There's no way they'd want to fund a foreign country's private company's R&D.
if i understand it properly it's strong suite is efficiency not raw power. it cannot make it out of a gravity well.
Quote from: ChrisWilson68 on 12/03/2014 09:33 amAs to the ESA or any other non-US government: they are generally only interested in spending money at home, where they can justify their existence by saying they are creating jobs. There's no way they'd want to fund a foreign country's private company's R&D.To be fair, they could be interested in technology transfer, but that would require moving Ad Astra to whatever country is paying for it, in essence.
That would involve ITAR and US State Department/DoD clearance to export, as it's probably (still) classified as a controlled item.
Quote from: Asteroza on 12/10/2014 10:03 pmThat would involve ITAR and US State Department/DoD clearance to export, as it's probably (still) classified as a controlled item.This is also true, and I can't figure out why I forgot to mention it. Logically, it wouldn't be a big deal because all of the theory is known, anyone who wants could probably develop it themselves (though it would take a while), and it's not really particularly useful for any military uses that I'm aware of, but these things rarely seem to have much to do with logic.
Quote from: Stormbringer on 12/10/2014 05:42 pmif i understand it properly it's strong suite is efficiency not raw power. it cannot make it out of a gravity well.So it couldn't be used for a purely terrestrial vehicle then. Just wondered if this was another avenue open to them.
Quote from: Star One on 12/10/2014 07:17 pmQuote from: Stormbringer on 12/10/2014 05:42 pmif i understand it properly it's strong suite is efficiency not raw power. it cannot make it out of a gravity well.So it couldn't be used for a purely terrestrial vehicle then. Just wondered if this was another avenue open to them.No. These sort of thrusters only work in a vacuum.
...There's no money to be made from VASIMR ...As to the ESA or any other non-US government: they are generally only interested in spending money at home, where they can justify their existence by saying they are creating jobs. There's no way they'd want to fund a foreign country's private company's R&D.
Quote from: Raj2014 on 12/01/2014 06:51 pmHas Franklin Chang Diaz asked other aerospace companies to test VASIMR? Does he have enough money to make a small spacecraft to test the VX-200?. If NASA can not give funding, I think Franklin should ask Elon Musk or ask other aerospace companies for funding e.g. ESA for funding or international funding.No other aerospace company is interested in funding VASIMR. Except for SpaceX, other aerospace companies fall into one of two categories:1. They have money to spend but take decisions based largely on making money.2. They might be interested in spending money for reasons other than making money, but have almost no money of their own and are desperately seeking investors.There's no money to be made from VASIMR, so category 1 companies won't spend money on it, and category 2 companies don't have any money to spend.SpaceX is the anomaly. But Elon's statements seem to indicate a lack of interest in VASIMR. He seems committed to chemical propulsion for colonizing Mars.As to the ESA or any other non-US government: they are generally only interested in spending money at home, where they can justify their existence by saying they are creating jobs. There's no way they'd want to fund a foreign country's private company's R&D.
SpaceX is the anomaly. But Elon's statements seem to indicate a lack of interest in VASIMR. He seems committed to chemical propulsion for colonizing Mars.
I have a spreadsheet of numbers somewhere - but they basically showed very little benefit in using electric propulsion to get from High Earth Orbit (e.g. Earth-Moon L1) to Mars, because SEP cannot use the Oberth effect and cannot use aero-capture at Mars.
Quote from: ChrisWilson68 on 12/03/2014 09:33 amSpaceX is the anomaly. But Elon's statements seem to indicate a lack of interest in VASIMR. He seems committed to chemical propulsion for colonizing Mars.I have a spreadsheet of numbers somewhere - but they basically showed very little benefit in using electric propulsion to get from High Earth Orbit (e.g. Earth-Moon L1) to Mars, because SEP cannot use the Oberth effect and cannot use aero-capture at Mars. Using these effects, a minimum delta-V from HEO to Mars Aeocapture entry is only 700m/s. Getting from LEO to HEO is the major delta-V challenge (about 4km/s). A SEP could be useful here provided it can handle the Van Allen radiation environment. It could be used to lift all the mission mass to HEO, apart from crew. And it could be reusable - a genuine space tug.
I assume SpaceX reckon their launch cost will be low enough that they won't need this. Just launch from LEO and keep it simple. Zubrin would agree. VASIMR will just complicate things, even if it does reduce in orbit mass. And complexity = cost.
Currently the VASIMR engines are operating over 60% efficiency; however, we have hit a wall on how to power the unit while in space. To achieve the amounts of power required for such a powerful engine, we would need to design some form of nuclear reactor, fusion reactor, or matter-antimatter reactor as a supply of power in space. Theoretically, you could use large solar panels as well; however, the weight for such panels would pose an issue at launch.
At a thickness of 20 nm, lithium has an areal density of 0.011 g/m2. A high-performance sail could be made of lithium alone at 20 nm (no emission layer). It would have to be fabricated in space and not used to approach the sun. In the limit, a sail craft might be constructed with a total areal density of around 0.02 g/m2, giving it a lightness number of 67 and ac of about 400 mm/s2. Magnesium and beryllium are also potential materials for high-performance sails. These 3 metals can be alloyed with each other and with aluminium.[2]
The trick with aerocapture and solar electric propulsion is getting the featherweight solar collectors to survive the aerocapture maneuver.
Quote from: Hanelyp on 12/13/2014 05:48 pmThe trick with aerocapture and solar electric propulsion is getting the featherweight solar collectors to survive the aerocapture maneuver.I suppose you could abandon the VASIMR its solar panels, and aerocapture the rest of the craft. Seems a bit of a waste.