Cost. Its lower cost way to add extra habitat modules. I think there is still a need for a few essential purpose built modules.With every Cygnus mission they would get extra habitat module from US tank.In case of Xeus lander, it is extra lunar habitat volume for every cargo lander.
Also, here's a copy of my short (~5min) Von Braun Symposium presentation for those who weren't able to watch it live or online on Thursday. I don't know that there's a huge amount of new information there, but it was a good discussion.~Jon
QuoteWith up to 310 m3 habitable volume Ixion is the largest single element station since SkyLabHow do you get this number, isn't the Centaur relatively small? Some of the volume would be in the "mission module" but that looks small. Are you counting an additional cygnus-like module on top?Hydrolox density is about 360 kg/m so the current centaur with 23 ton of propellant would have ~60 m3 of volume. 310 m3 volume would hold more than 100 tons of hydrolox.
With up to 310 m3 habitable volume Ixion is the largest single element station since SkyLab
How is a wet lab "better" than a dry lab? Why would NASA want this rather than say a BA330?
Quote from: TrevorMonty on 10/28/2017 07:24 pmCost. Its lower cost way to add extra habitat modules. I think there is still a need for a few essential purpose built modules.With every Cygnus mission they would get extra habitat module from US tank.In case of Xeus lander, it is extra lunar habitat volume for every cargo lander. What is the cost range to for wet lab vs a dry lab?
Quote from: jongoff on 10/28/2017 04:14 pmAlso, here's a copy of my short (~5min) Von Braun Symposium presentation for those who weren't able to watch it live or online on Thursday. I don't know that there's a huge amount of new information there, but it was a good discussion.~Jon That diagram shows IXION using both a Mission Module and a Wet Lab. The combination makes sense, where as a Wet Lab by itself does not. All the complex stuff is launched in the Mission Module and arrives at the same time.
Quote from: HIP2BSQRE on 10/28/2017 07:30 pmQuote from: TrevorMonty on 10/28/2017 07:24 pmCost. Its lower cost way to add extra habitat modules. I think there is still a need for a few essential purpose built modules.With every Cygnus mission they would get extra habitat module from US tank.In case of Xeus lander, it is extra lunar habitat volume for every cargo lander. What is the cost range to for wet lab vs a dry lab?I don't think we have great numbers for comparison (it's not like Bigelow publishes their cost numbers). But most of the pressure structure for Ixion is made on the same tank fabrication tooling as the upper stage, which keeps the mass efficiency high and the cost relatively low. And since you can do most of the complex outfitting on the ground without requiring as much labor time on orbit, that should also be a win. Your launch costs should be lower too because half your volume is already paid for in getting the upper stage to orbit in the first place, and the rest of your structure is very mass efficient.That doesn't prove it would be cheaper, but it suggests it likely is.~Jon
Quote from: jongoff on 10/29/2017 04:14 amQuote from: HIP2BSQRE on 10/28/2017 07:30 pmQuote from: TrevorMonty on 10/28/2017 07:24 pmCost. Its lower cost way to add extra habitat modules. I think there is still a need for a few essential purpose built modules.With every Cygnus mission they would get extra habitat module from US tank.In case of Xeus lander, it is extra lunar habitat volume for every cargo lander. What is the cost range to for wet lab vs a dry lab?I don't think we have great numbers for comparison (it's not like Bigelow publishes their cost numbers). But most of the pressure structure for Ixion is made on the same tank fabrication tooling as the upper stage, which keeps the mass efficiency high and the cost relatively low. And since you can do most of the complex outfitting on the ground without requiring as much labor time on orbit, that should also be a win. Your launch costs should be lower too because half your volume is already paid for in getting the upper stage to orbit in the first place, and the rest of your structure is very mass efficient.That doesn't prove it would be cheaper, but it suggests it likely is.~JonPart of the cost is the mass of the Ixion module is the reduced mass and volume of the paying payload.Is there a stretched Ixion module about half of which can be used instead of a Cygnus?
I don't think we have great numbers for comparison (it's not like Bigelow publishes their cost numbers). But most of the pressure structure for Ixion is made on the same tank fabrication tooling as the upper stage, which keeps the mass efficiency high and the cost relatively low. And since you can do most of the complex outfitting on the ground without requiring as much labor time on orbit, that should also be a win. Your launch costs should be lower too because half your volume is already paid for in getting the upper stage to orbit in the first place, and the rest of your structure is very mass efficient.That doesn't prove it would be cheaper, but it suggests it likely is.~Jon
Quote from: HIP2BSQRE on 10/28/2017 07:30 pmWhat is the cost range to for wet lab vs a dry lab?I don't think we have great numbers for comparison (it's not like Bigelow publishes their cost numbers). But most of the pressure structure for Ixion is made on the same tank fabrication tooling as the upper stage, which keeps the mass efficiency high and the cost relatively low. And since you can do most of the complex outfitting on the ground without requiring as much labor time on orbit, that should also be a win. Your launch costs should be lower too because half your volume is already paid for in getting the upper stage to orbit in the first place, and the rest of your structure is very mass efficient.That doesn't prove it would be cheaper, but it suggests it likely is.~Jon
What is the cost range to for wet lab vs a dry lab?
Quote from: jongoff on 10/29/2017 04:14 amI don't think we have great numbers for comparison (it's not like Bigelow publishes their cost numbers). But most of the pressure structure for Ixion is made on the same tank fabrication tooling as the upper stage, which keeps the mass efficiency high and the cost relatively low. And since you can do most of the complex outfitting on the ground without requiring as much labor time on orbit, that should also be a win. Your launch costs should be lower too because half your volume is already paid for in getting the upper stage to orbit in the first place, and the rest of your structure is very mass efficient.That doesn't prove it would be cheaper, but it suggests it likely is.~JonJon, has any work been done to look at feasibility on lunar surface like with Xeus?
I remain very skeptical that the conversion on-orbit is going to be as easy and/or cheap as proponents of wet lab concepts argue, but I certainly want them to give it a shot, so I can be proven wrong.
Now leaving a lander on the surface of the moon or Mars might be more practical. Gravity would allow the light hydrogen to escape out a top vent once purged with nitrogen.
Wasn't the main reason they didn't use a Saturn upper stage was trapped hydrogen or oxygen that didn't completely vent would or may cause an internal fire, especially hydrogen. Oxygen has to be breathed, and could be combined with nitrogen for stability. However, the larger tank would be the hydrogen if you are needing space. Sounds good, but it could be dangerous. A lot of purging would have to be done.
Beyond this, the problem I see is external blankets of Kevlar may have to be installed. Radiation shielding on the inside may need to be installed. A lot of internal construction would be required.
Now leaving a lander on the surface of the moon or Mars might be more practical. Gravity would allow the light hydrogen to escape out a top vent once purged with nitrogen. It could then be outfitted for habitat on the surface. Of course any engines remaining would be wasted, unless disconnected and shipped back for some type of reuse.