Human Rated Atlas V for Bigelow Space Station details emerge

[clongton]

braddock - 5/2/2007  10:36 AM
If ... LEO refueling is still attractive enough, it could become the centerpiece of an extended NASA roadmap to permanent moon bases and Mars.  It could help take the place of in-situ fuel generation.

Better yet, what if the in-situ fuel generation plants were on the moon? What's the cost delta between sending a ton of fuel to a LEO fuel depot from the earth (deep gravity well) as opposed to sending it to the same depot from the moon (shallow gravity well)? I know this is long-viewed, but doesn't it make sense for the moon to eventually be the fuel generation location, instead of the earth?

[jongoff]

Braddock,

What would be the increase in payload to lunar surface if the EDS could be filled/refilled in LEO?
What would be the increase in payload to lunar surface if the EDS could be REUSED as a tug, and hang out at the fuel station?

I'm not entirely sure, but if you top off the EDS, but otherwise expend it like per the current ESAS plan, you could increase the payload to the lunar surface by somewhere between 30-50% per mission.  If you use the EDS as a reusable tug, it would be somewhat lower than that.  Probably closer to 25-40%.  I can try digging up some numbers if you'd like.

~Jon

[Zond]

This recent document has some interesting info about orbital propellant depots: In-Space Cryogenic Propellant Depot Potential Commercial and Exploration Applications (24,9 MB ,PDF)

[Bill White]

clongton - 5/2/2007  10:16 AM

braddock - 5/2/2007  10:36 AM
If ... LEO refueling is still attractive enough, it could become the centerpiece of an extended NASA roadmap to permanent moon bases and Mars.  It could help take the place of in-situ fuel generation.

Better yet, what if the in-situ fuel generation plants were on the moon? What's the cost delta between sending a ton of fuel to a LEO fuel depot from the earth (deep gravity well) as opposed to sending it to the same depot from the moon (shallow gravity well)? I know this is long-viewed, but doesn't it make sense for the moon to eventually be the fuel generation location, instead of the earth?

Lunar LOX and Terran H2 or CH4 would make a terrific combination. LOX can be extracted from anywhere on the Moon. H2 from cold trap ice would be largely restricted to polar locations.

EML-1 & EML-2 also make terrific locations for fuel depots giving equal access to the entire Moon.

= = =

Of course, MXER tethers deployed in LEO offer many of the same advantages as LEO fuel depots. Dry launch and sling your payload to the Moon.

[Kayla]

jongoff - 5/2/2007  10:34 AM

Braddock,

What would be the increase in payload to lunar surface if the EDS could be filled/refilled in LEO?
What would be the increase in payload to lunar surface if the EDS could be REUSED as a tug, and hang out at the fuel station?

I'm not entirely sure, but if you top off the EDS, but otherwise expend it like per the current ESAS plan, you could increase the payload to the lunar surface by somewhere between 30-50% per mission.  If you use the EDS as a reusable tug, it would be somewhat lower than that.  Probably closer to 25-40%.  I can try digging up some numbers if you'd like.

~Jon

"topping off" the EDS in LEO can increase lunar payload from almost nothing to over 20 mT:
http://www.lockheedmartin.com/data/assets/13351.pdf

[JIS]

meiza - 5/2/2007  3:13 PM

I meant to say, orbital propellant transfer could be demonstrated in a short time.

When? How?
5-10Years? Two complex satelites with docking system are several $B.

[meiza]

The actual zero gee propellant transfer could be demonstrated on a Centaur flying a normal payload to orbit. Lockheed Martin has papers on this.
Rendezvous and docking is a different beast then. There are multiple approaches to do that.

[Zond]

JIS - 6/2/2007  1:17 PM

meiza - 5/2/2007  3:13 PM

I meant to say, orbital propellant transfer could be demonstrated in a short time.

When? How?

The russians have been doing it for thirty years with Progress and Salyut/Mir/ISS.
And DARPA/NASA is planning to launch Orbital Express this month.

5-10Years? Two complex satelites with docking system are several $B.

Orbital Express is costing $267.4 million. And i believe a Progress vehicle will set you back something in the neighbourhoud of $50 million. Unless you are building JWST or some new spy satellite loaded with gadgets you will have a difficult time finding a sattelite that costs several billion dollars.
With several billion dollars you could propably build yourself a decent propellant depot.

[jongoff]

Jim,

When? How? 5-10Years? Two complex satellites with docking system are several $B.

Well, lets see.  Non-cryo propellant transfer has been demonstrated for decades.  Using state of 1960s/70s Soviet technology nonetheless!  I wouldn't be surprised if we had a demonstration of settled cryogenic transfer within the next 2-3 years.  The technology is not the challenge.  Centaur "transfers" cryogenic propellants from its tanks to its engines through several valves (and a turbopump) in zero-G all the time.  They've been doing it for decades.  The only challenge is finding a market big enough to justify the remaining development cost.

I'm working on that angle.

And no, it won't involve complex satellites that cost several $B.  You could do it that way, but that would be dumb.  There are much cheaper ways of doing such things.

~Jon

[jongoff]

Zond,

Orbital Express is costing $267.4 million. And i believe a Progress vehicle will set you back something in the neighborhood of $50 million. Unless you are building JWST or some new spy satellite loaded with gadgets you will have a difficult time finding a satellite that costs several billion dollars.
With several billion dollars you could probably build yourself a decent propellant depot.

You could probably build a decent first-gen propellant depot for far less than that.  But yeah, your basic point that JIS's "Several $B" comment was just handwaving stands.  

~Jon

"When you want something you'll find a way, when you don't want something, you'll find an excuse" --Tagalog Proverb

[jongoff]

JIS,

So essentially NASA would pay to develop ESAS stuff (except for compilation of Ares 1 from building blocks for Ares V) and more over would pay for LEO depot (dedicated to VSE) and development/operation of private tankers.

Nope.  Not what I'm saying at all.  They *could* pay some of the development cost for the LEO depot/tankers, with private sources putting a substantial amount of skin in the game.  Or they could offer prizes to demonstrate a couple of the key technologies (they're already anemically starting to do this, at least in theory).  Best yet would be if they set some money aside in some sort of trust fund.  Say enough money to pay to tank up a year's worth of EDS flights, at a good price.  To be paid out on delivery.  Personally, I think that that would be preferable.

But even if they don't do anything to help the market out, commercial LEO propellant depots will likely be a going concern before Ares I ever flies a manned mission.  It's just that if NASA actually followed its legal requirement to promote the commercial development of space, instead of competing against it, it would make such an eventually even more likely.

I think it's much worse idea than COTS.

Of course you do.  My feelings aren't hurt.  

NASA have many other means to get to ISS if COTS fails, there is no other mean to get to the Moon if depot or new private tanker industry fail.

Nonsense.  If you do what I suggested with the escrow account, you set a deadline on that, such that if the capability isn't ready by that point, that the money gets transfered back to Ares-V/EDS/LSAM development.

I'm not sure that this would be the safest, fastest and cheapest way to the Moon.

If all you care about is some sort of easily cancelable, unsustainable, waste of taxpayer money, "round off error" of a moon program, then you're quite right.  If you'd like to see anything useful come out of VSE, then I think you're completely wrong.

Let's built depot when there is true capability to do that (Bigelow on orbit facility with private servicing) and clear demand from more costumers (VSE plus other potential gov or private users).

I wasn't suggesting building a propellant depot right this instant, I was just suggesting that NASA follow the law and actually try promoting commercial space development by acting as a customer.  If NASA acted as a stable customer for 200-300klb of propellant per year, I can guarantee you that other markets would also come along, and probably quickly.  If NASA isn't a customer, it might be possible to bootstrap your way through those other markets (and I intend to try), but it's far less certain.

But either way, it'll still be flying before any metal has been bent for Ares V.

These are big tasks for the small private space industry of today. And it will take many years to get there. Bigelow took over his technology from NASA and still doing his first baby steps. Space X has hard time to launch it's test rocket and RpK will spend at least billion before their first test launch. Others are starting tech demonstration at the best.
Even suborbital private flights haven't materialised yet.

You forget however that Lockheed and Boeing have existed (in various forms) for over 50 years now.  They've been launching things reliably, and a first-gen propellant depot could start even if RpK and SpaceX fail.  Though Bigelow succeeding would help immensely.  Private space isn't just plucky alt.space companies.  It also includes the dinosaurs when they decide to act mammalian.

~Jon

[clongton]

meiza - 6/2/2007  11:07 AM

The actual zero gee propellant transfer could be demonstrated on a Centaur flying a normal payload to orbit. Lockheed Martin has papers on this.

There was a fairly good presentation of cryogenic propellant transfer done by the AIAA titled “Settled Cryogenic Propellant Transfer”. It’s AIAA 2006-4436. You can find it here: www.lockheedmartin.com/data/assets/13351.pdf
This might be one of the papers you're referring to.

[josh_simonson]

The EDS would need to be built with the capability to be re-fueled and maintained in orbit, such as attachment points to collect LH2 boiloff for reliquification and return to the EDS.  Also if RCS is used to settle the propellant the EDS will need attachment points to hold it in place.  

To ensure that the stock EDS is built with a useful configuration for this requires that a generic depot scheme be developed by the time the EDS is being developed, and that the company(s) doing that work coordinate with NASA on it to ensure that orbital fuel transfer is safe and simple with a stock EDS.

The elephant in the room for this scenario is the Aries V - it's very unlikely that anyone, even russia, will be able to fly bulk cargo at a per/lb rate that is lower than the incremental per/lb cost of launching another Aries V.  If Aries V costs turn out like the Shuttle, an additional Aries V would be more or less free.  This may well make the best orbital fuel depot scheme involve a private depot and a streched EDS launched on the Aries V.  Perhaps an orbital tug to assist in docking the EDS with the depot as well.

Fuel delivery to an EML1 depot is less straightforward than an LEO depot, solar electric and/or electrodynamic propulsion may be able to get fuel there from earth cheaper than Aries V could, and lunar ISRU also becomes a possibility.

[braddock]

How badly does the need to rendezvous with an LEO refueling station limit launch opportunities to a particular lunar landing site?

[meiza]

josh_simonson - 6/2/2007  9:07 PM

The EDS would need to be built with the capability to be re-fueled and maintained in orbit, such as attachment points to collect LH2 boiloff for reliquification and return to the EDS.  Also if RCS is used to settle the propellant the EDS will need attachment points to hold it in place.  

Not if you keep the propellant in the depot, not in the EDS. The depot can be heavy and have 40 layers of insulation and a sunshield. It can even have a robot arm to capture the EDS/LSAM/CEV/tanker for berthing.
You launch the EDS so that it doesn't have any propellant once it reaches orbit. (Or alternatively any LOX if you have a LOX only depot.)

To ensure that the stock EDS is built with a useful configuration for this requires that a generic depot scheme be developed by the time the EDS is being developed, and that the company(s) doing that work coordinate with NASA on it to ensure that orbital fuel transfer is safe and simple with a stock EDS.

The elephant in the room for this scenario is the Aries V - it's very unlikely that anyone, even russia, will be able to fly bulk cargo at a per/lb rate that is lower than the incremental per/lb cost of launching another Aries V.  If Aries V costs turn out like the Shuttle, an additional Aries V would be more or less free.  This may well make the best orbital fuel depot scheme involve a private depot and a streched EDS launched on the Aries V.  Perhaps an orbital tug to assist in docking the EDS with the depot as well.

Fuel delivery to an EML1 depot is less straightforward than an LEO depot, solar electric and/or electrodynamic propulsion may be able to get fuel there from earth cheaper than Aries V could, and lunar ISRU also becomes a possibility.

I don't predict it's that useful anymore to do depots once you have wasted the billions in developing Ares I and V and keep them operational and the standing armies waiting. Launch as many ones and vees as you can, every year, it doesn't cost much more than launching none, if the capability is kept on the threshold. That way you get the most bang for the buck. Ares V is nice in that it can put a lot of payload to the lunar surface all by itself.
You need something for the Mars launch though but there are so many exploration strategies and configuration and propulsion choices still that it's a mess.

You can then let the other rocket factories that existed already way back in 2002 get spiderwebs around their 40 boosters per year production lines, since you had to have your one true NASA way with billions of dollars and a decade of delay.

(Btw, a minor nit to set things straight, it's Ares, not Aries. There's no i in Ares.)

[jongoff]

Josh,

jThe EDS would need to be built with the capability to be re-fueled and maintained in orbit, such as attachment points to collect LH2 boiloff for reliquification and return to the EDS.  Also if RCS is used to settle the propellant the EDS will need attachment points to hold it in place.

You don't *have* to reliquify boiled off GH2.  You can just vent it like Centaur does.  As it is, Doug Stanley was saying that they were trying to design the EDS so as not to preclude refueling precisely because refueling makes so much economic and performance sense.

To ensure that the stock EDS is built with a useful configuration for this requires that a generic depot scheme be developed by the time the EDS is being developed, and that the company(s) doing that work coordinate with NASA on it to ensure that orbital fuel transfer is safe and simple with a stock EDS.

I'm not too worried.  Actual serious development work on the EDS won't start till the 2012-2016 time frame (if budget cuts don't push it out even further).  I'd be really surprised if nobody has a commercial depot by then, or at least one in the works that they could work with NASA on.  But my bet is that there will be a working system with a standard interface by the time NASA gets around to doing the EDS.

The elephant in the room for this scenario is the Aries V - it's very unlikely that anyone, even russia, will be able to fly bulk cargo at a per/lb rate that is lower than the incremental per/lb cost of launching another Aries V.  If Aries V costs turn out like the Shuttle, an additional Aries V would be more or less free.  This may well make the best orbital fuel depot scheme involve a private depot and a streched EDS launched on the Aries V.  Perhaps an orbital tug to assist in docking the EDS with the depot as well.

I'll believe that when I see it.  The only thing I believe less than NASA cost estimates is NASA safety predictions.  

Fuel delivery to an EML1 depot is less straightforward than an LEO depot, solar electric and/or electrodynamic propulsion may be able to get fuel there from earth cheaper than Aries V could, and lunar ISRU also becomes a possibility.

L1 depots can initially (at some cost) be replenished from earth, but in the long run lunar ISRU will be what it takes to make them really workable.

Just my $.02

~Jon

[meiza]

Incidentally, even the swedes are going to test remote orbital formation flying and rendezvous, with the Prism program in 2009, as mentioned here:
http://www.ssc.se/default.asp?groupid=2005929142335959

[BarryKirk]

Well, a LOX only depot makes a lot of sense.

1) The boiloff rate for LOX is lower than for LH2.
2) The LOX is a lot heavier than LH2.

So, if the heavy LOX is offloaded from the EDS so that the launcher doesn't have to boost it to orbit.  Than the booster can be a lot smaller.

Question, is most of the mass of an EDS stage the LOX?  I'm including the  payload in this.

[Jim]

yes, because there is LOX in the payload

[meiza]

From the FLEX draft document (assuming a 6:1 O:F ratio):
Table 2: Stack Propellant Breakdown. t means 1000 kg

Name	Empty mass, t	Propellant mass	Of which LOX, t
CEV	14	9	0
LSAM	14	30	25
EDS	18	85*	73
TOTAL:	46	124	98

LOX is a pretty obvious choice. The stack consists of 46 tons
of spacecraft, 124 tons of propellants of which 98 tons is liquid
oxygen. Our depot needs to only hold liquid oxygen to be extremely
useful for a lunar architecture.