If by “green” they mean “produces no CO2”, then we already have it. It’s called Hydrogen. Or Hydroen Peroxide, if you want monopropellant.
The usual means of producing hydrogen release plenty of CO2, however.
Sure, you could use methane to make H2, but one can also use electrolysis of water and a nuclear plant to make the electricity. Same with H2O2.
You could, but it would be very expensive compared to making it from methane. Granted, the CO2 could be separated out and pumped underground (probably more cheaply than making H2 from electrolysis), but no one does that.
Ammonium dinitramide isn’t made in the United States, and costs on the order of $2,000 per kilogram. In anhydrous form, it is shock sensitive and detonates when it goes off.
ALL propellants have hazards. Personally, I think the hazards of hydrazine are overblown, and I’ve had personal experience with both it and monomethylhydrazine. Rubber gloves and aprons, and a faceshield, used to be sufficient protection (and still are for the people who pour it into boilers to descale them).
It’s all in your perception of risk, and of what constitutes the ultimate outcome of something. I was in a meeting at NOAA where the head of Yuzhnoye was trying to get the United States to allow its military satellites to be launched on Dnepr (the reconstituted SS-18 ICBM). He had a great sales pitch, which at one point became almost hilarious. He referred to the Dnepr propellants (nitrogen tetroxide and unsymmetrical dimethylhydrazine) as “green.” Seeing the looks of bewilderment on the American side, he said (correctly) that both propellants ultimately fix nitrogen in the soil and fertilize plant life.
He should have known better. After all, this is America, where opposition to the two requirements for all plant life, carbon dioxide in the atmosphere and warm temperatures, are opposed by people who call their opposition “Green.”
That should have been “…where the two requirements for all plant life…”
If we don’t use hydrazine, how will “The Martian” astronaut Mark Watney concoct “water” even if he does know the recipe?
A frequently overlooked point in the discussion of the book and movie is that had Watney depended on “free” solar energy, he’d have died. He had to go get a plutonium reactor in order to fulfill his goal to “science the shit” out of his situation. The plutonium in the story, by the way, seems to have been sent there, pre-positioned, in order to make hydrazine out of the CO2 already in Mars’ air, plus hydrogen shipped from earth and use that fuel for the return liftoff.
ANYHOW, the point is not whether or not to get way from hydrazine but to get BACK to rational use of plutonium.
I’m not really impressed by this “green” propellant. XCOR has/had a couple of non-toxic reaction control systems going back at least a decade using cheaper biprop combinations. Some, if not all, of the XCOR RCS motors were regeneratively cooled and capable of an arbitrary number of starts.
We’ve never tried to do a monoprop at XCOR, partly because I personally sit right next to these engines and run them. Back in 1988 at Hummingbird I tried to do a monoprop of ammonium nitrate-water-methanol, but it had to be kept hot to keep the AN in solution, had poor predicted Isp, and I never did manage to get it to light off and run. In retrospect I’m sort of glad it was a disappointment, I was rather ignorant back then.
Our ONA system uses gaseous oxygen and a “highly oxygenated fuel” that runs about $1500/drum (with shipping) straight from the chemical supply house. I got some splashed in my eyes last year, painful but only a nuisance (I had flipped up my face shield at *just* the wrong moment) and I was fine the next day. The problem with monopropellants is that they pretty much by definition have to be high strung unstable materials, while adding a little oxygen and a spark-torch igniter for starting a more stable fuel makes for a much better behaved system.
Thanks, Doug. I always enjoy tales of your rocket whispering.
Can this new “green” prop be used as a hypergolic biprop, like hydrazine? Or is it only useful, at most, as a monoprop?
Personally, I’d be in favor of an alternative to hydrazine/nitrogen tetroxide as a hypergolic on manned craft, due to the toxicity and handling issues, if doing so would not result in an effeciancy or cost hit (and would not need to be imported).
Hydrazine for monoprop on an unmanned satellite, though… where’s the harm? Unless what replaces it offers better performance/lower cost, why bother?
If, and it’s a big if, the claim that the new fuel is more efficient than hydrazine pans out, it might actually be worthwhile looking at IMHO. However, my guess is that, for station-keeping on sats, solar-electric will be the gold standard soon, due to far higher ISP.
“Hydrazine for monoprop on an unmanned satellite, though… where’s the harm?”
Commercial space flight lives or dies by logistics, and the safety measures to handle hydrazine are expensive. Cleaning up launch failures is especially expensive, potentially tying up the launch pad for weeks.
If by “green” they mean “produces no CO2”, then we already have it. It’s called Hydrogen. Or Hydroen Peroxide, if you want monopropellant.
The usual means of producing hydrogen release plenty of CO2, however.
Sure, you could use methane to make H2, but one can also use electrolysis of water and a nuclear plant to make the electricity. Same with H2O2.
You could, but it would be very expensive compared to making it from methane. Granted, the CO2 could be separated out and pumped underground (probably more cheaply than making H2 from electrolysis), but no one does that.
Ammonium dinitramide isn’t made in the United States, and costs on the order of $2,000 per kilogram. In anhydrous form, it is shock sensitive and detonates when it goes off.
ALL propellants have hazards. Personally, I think the hazards of hydrazine are overblown, and I’ve had personal experience with both it and monomethylhydrazine. Rubber gloves and aprons, and a faceshield, used to be sufficient protection (and still are for the people who pour it into boilers to descale them).
It’s all in your perception of risk, and of what constitutes the ultimate outcome of something. I was in a meeting at NOAA where the head of Yuzhnoye was trying to get the United States to allow its military satellites to be launched on Dnepr (the reconstituted SS-18 ICBM). He had a great sales pitch, which at one point became almost hilarious. He referred to the Dnepr propellants (nitrogen tetroxide and unsymmetrical dimethylhydrazine) as “green.” Seeing the looks of bewilderment on the American side, he said (correctly) that both propellants ultimately fix nitrogen in the soil and fertilize plant life.
He should have known better. After all, this is America, where opposition to the two requirements for all plant life, carbon dioxide in the atmosphere and warm temperatures, are opposed by people who call their opposition “Green.”
That should have been “…where the two requirements for all plant life…”
If we don’t use hydrazine, how will “The Martian” astronaut Mark Watney concoct “water” even if he does know the recipe?
A frequently overlooked point in the discussion of the book and movie is that had Watney depended on “free” solar energy, he’d have died. He had to go get a plutonium reactor in order to fulfill his goal to “science the shit” out of his situation. The plutonium in the story, by the way, seems to have been sent there, pre-positioned, in order to make hydrazine out of the CO2 already in Mars’ air, plus hydrogen shipped from earth and use that fuel for the return liftoff.
ANYHOW, the point is not whether or not to get way from hydrazine but to get BACK to rational use of plutonium.
I’m not really impressed by this “green” propellant. XCOR has/had a couple of non-toxic reaction control systems going back at least a decade using cheaper biprop combinations. Some, if not all, of the XCOR RCS motors were regeneratively cooled and capable of an arbitrary number of starts.
We’ve never tried to do a monoprop at XCOR, partly because I personally sit right next to these engines and run them. Back in 1988 at Hummingbird I tried to do a monoprop of ammonium nitrate-water-methanol, but it had to be kept hot to keep the AN in solution, had poor predicted Isp, and I never did manage to get it to light off and run. In retrospect I’m sort of glad it was a disappointment, I was rather ignorant back then.
Our ONA system uses gaseous oxygen and a “highly oxygenated fuel” that runs about $1500/drum (with shipping) straight from the chemical supply house. I got some splashed in my eyes last year, painful but only a nuisance (I had flipped up my face shield at *just* the wrong moment) and I was fine the next day. The problem with monopropellants is that they pretty much by definition have to be high strung unstable materials, while adding a little oxygen and a spark-torch igniter for starting a more stable fuel makes for a much better behaved system.
Thanks, Doug. I always enjoy tales of your rocket whispering.
Can this new “green” prop be used as a hypergolic biprop, like hydrazine? Or is it only useful, at most, as a monoprop?
Personally, I’d be in favor of an alternative to hydrazine/nitrogen tetroxide as a hypergolic on manned craft, due to the toxicity and handling issues, if doing so would not result in an effeciancy or cost hit (and would not need to be imported).
Hydrazine for monoprop on an unmanned satellite, though… where’s the harm? Unless what replaces it offers better performance/lower cost, why bother?
If, and it’s a big if, the claim that the new fuel is more efficient than hydrazine pans out, it might actually be worthwhile looking at IMHO. However, my guess is that, for station-keeping on sats, solar-electric will be the gold standard soon, due to far higher ISP.
“Hydrazine for monoprop on an unmanned satellite, though… where’s the harm?”
Commercial space flight lives or dies by logistics, and the safety measures to handle hydrazine are expensive. Cleaning up launch failures is especially expensive, potentially tying up the launch pad for weeks.