How will the Bigelow Lunar Station be transported to LEO & on to EML-1?

[ChefPat]

Bigelow said recently that he intends to put station consisting of 3 BA-330 modules & 4 Propulsion/Power Busses on on the Lunar Surface. In that statement he said the station would be assembled at EML-1 & then sent complete to The Moon & land under it's own power.
My question is, using currently available or in planning transport, how will all the necessary equipment be placed in LEO & then sent on to be assembled at EML-1?

[Downix]

Bigelow said recently that he intends to put station consisting of 3 BA-330 modules & 4 Propulsion/Power Busses on on the Lunar Surface. In that statement he said the station would be assembled at EML-1 & then sent complete to The Moon & land under it's own power.
My question is, using currently available or in planning transport, how will all the necessary equipment be placed in LEO & then sent on to be assembled at EML-1?

You just need two bits to do it.  1) assembly core, for the modules to attach to, and 2) ion drives, for a slow movement to the final resting spot.  So long as you don't rush, it is easy to get somewhere.

[mmeijeri]

Wouldn't you need an impractical amount of power for that? Construction in LEO is easier than at L1/L1, but getting things to L1/L2 is easier if you do it piece by piece. If you had propellant transfer and an upper stage that's a bit bigger than DCUS it should be doable, but Bigelow can't fund all that. I wonder what his plan is.

[Bernie Roehl]

Wouldn't you need an impractical amount of power for that? Construction in LEO is easier than at L1/L1, but getting things to L1/L2 is easier if you do it piece by piece. If you had propellant transfer and an upper stage that's a bit bigger than DCUS it should be doable, but Bigelow can't fund all that. I wonder what his plan is.

If Ad Astra's SEP freighter actually flies, moving something from LEO to EML1/2 (or even LLO) will be easy and relatively cheap.

Getting the fully assembled structure down to the lunar surface, though, is a whole other thing.  I think it makes way more sense to send it down in individual modules and assemble it on the surface.

[mmeijeri]

If Ad Astra's SEP freighter actually flies, moving something from LEO to EML1/2 (or even LLO) will be easy and relatively cheap.

I suspect it will be a long time before that happens.

[Bernie Roehl]

If Ad Astra's SEP freighter actually flies, moving something from LEO to EML1/2 (or even LLO) will be easy and relatively cheap.

I suspect it will be a long time before that happens.

Well, the technology seems sound enough, and they're planning a test in the next few years of a thruster that should do the job.  Cluster a few of those and attach them to a large solar array and you should be good to go.

If you have any information about why this wouldn't work, let me know... I'd be curious.

[mmeijeri]

The need for a large solar array and the fact that the thing either has to be useful at its destination (plausible) or reusable. Reusable is difficult because of radiation damage. Now there are promising solutions to the radiation damage, so who knows. But as far as I understand it the whole problem with VASIMR is finding a power source. ENTECH no longer claims it can build radiation resistant tugs soon, they recently proposed a solar power beaming satellite in LLO as a precursor.

[Robotbeat]

http://www.space-travel.com/reports/Boeing_Team_To_Develop_Revolutionary_Spacecraft_Power_System_999.html
Boeing Team To Develop Revolutionary Spacecraft Power System
Jul 03, 2009

An industry team led by Boeing has received a contract from the Defense Advanced Research Projects Agency (DARPA) for work on Phase 2 of the Fast Access Spacecraft Testbed (FAST) program. The $15.5 million cost-plus-fixed-fee contract is currently funded to $13.8 million.

DARPA's FAST program aims to develop a new, ultra-lightweight High Power Generation System (HPGS) that can generate up to 175 kilowatts - more power than is currently available to the International Space Station. When combined with electric propulsion, FAST will form the foundation for future self-deployed, high-mobility spacecraft to perform ultra-high-power communications, space radar, satellite transfer and servicing missions.

Boeing Phantom Works of Huntington Beach is leading the effort with support from Boeing Network and Space Systems, El Segundo, Calif. The Phase 2 work will include designing, fabricating and integrating test articles, performing a series of component-level evaluations and running two full-scale system tests.

"Our team is pleased to partner with DARPA in developing this powerful new technology," said Tom Kessler, FAST program manager, Boeing Advanced Network and Space Systems. "FAST offers significant cost and performance benefits to our commercial, civil and national security customers, including new high-power applications to provide a cost-effective means for spacecraft to travel to the outer solar system."

During Phase 1 of the program, the Boeing-led team, which includes DR Technologies, Northrop Grumman Astro Aerospace, Texas A and M University, Emcore, Boeing subsidiary Spectrolab Inc., and other key suppliers, developed a preliminary design for an HPGS capable of providing more than 130 watts per kilogram on a system that is less than half the weight and one sixth the size of an existing on-orbit solar power system.

The team also defined the test program being conducted in Phase 2, which will verify the performance and operation of the HPGS's solar concentration, power conversion, heat rejection, structure and deployment, and sun pointing and tracking subsystems.

The Boeing team's unique solar concentrator design offers higher performance and greater radiation tolerance than current on-orbit solar power generation systems. Boeing will also be using different approaches to solar cell technology to include capabilities from Emcore and Spectrolab.

The size efficiency of the HPGS enables a new class of compact spacecraft that can self-deploy from low-Earth orbit to reach their final orbit using electric propulsion. This permits the use of smaller, less expensive launch vehicles that can support high-value science missions to the outer solar system without the need for expensive radioisotope power systems.

(emphasis mine)

[Bernie Roehl]

developed a preliminary design for an HPGS capable of providing more than 130 watts per kilogram on a system that is less than half the weight and one sixth the size of an existing on-orbit solar power system.

Interesting.

The proposed Ad Astra "space tug" would use 5 VX-200 engines powered by a 1 MW supply.  Each engine weighs 300 kg (1500 kg total), and at 130 w/kg a 1 MW supply would be less than 8000 kg.  So the tug would weigh less than 10 metric tons, and could easily be put in orbit on a single launch of an EELV, even allowing some extra mass for structure, payload interfaces, etc.  If you launch it on a Delta IV Heavy, you could even carry enough propellant for a full test flight to EML1 and back.


 

[Robotbeat]

It should be noted that typical high-end triple-junction space-qualified solar cells are 30% efficient (okay, fine, 29.9%) and are available from multiple suppliers. Spectrolab has had the record for solar cell efficiency at 40.7%, a number which has been increasing gradually for a while (now it's at about 43%, depending on who you ask). This would reduce the area of a solar array by a little more than 25%.

Thin-film solar arrays are now at (for state-of-the-art) about 20% efficiency, and these types can be ridiculously thin, since they use vapor-deposition processes. If it turns out we can't get concentrating solar to be light enough, thin-film solar cells definitely can be made light enough (>1kw/kg), at the expense of size.

Anyways, for getting something from LEO to EML1/2/LLO, you can trade specific power for time (assuming you have really good radiation-resistance) with electric propulsion.

BTW, this is from the FAST project's DARPA page:
http://www.darpa.mil/tto/programs/fast/index.html

The goal of the Fast Access Spacecraft Testbed (FAST) program is to demonstrate a suite of critical technologies including high efficiency solar cells, sunlight concentrating arrays, large deployable structures and ultra light weight solar arrays. These technologies enable light weight, high efficiency and high-power satellites, 20 kW scalable to 80 kW or more. The specific power goal is 130 W/Kg yielding an ultra lightweight power system of approximately 150 Kg for a 20 kW array. Combined with electric propulsion, FAST enables fast-transfer roaming satellites with nearly five times the fuel efficiency of conventional chemical propulsion.
FAST Spacecraft

For example, FAST will permit on-demand access to any point on the geosynchronous ring or within the high-altitude, super synchronous “graveyard” (where derelict systems are regularly repositioned in order to free up orbital slots within the ring), greatly improving our ability to rapidly deploy and reposition satellites, as well as monitor the geosynchronous environment. Alternatively, FAST will permit responsive launch capabilities including deployment of small geosynchronous satellites on small launch vehicles. Scaled up systems will nearly double the effective satellite mass launched to high altitude orbits today, significantly downsizing the need for large launch vehicles.

[notsorandom]

The radiation that has been mentioned is deep space solar and cosmic radiation correct? There are many solar powered probes that have been launched outside of the magnetosphere with older photo voltaic technology. Are these new lighter panels more susceptible to radiation damage?

[Bernie Roehl]

The radiation that has been mentioned is deep space solar and cosmic radiation correct? There are many solar powered probes that have been launched outside of the magnetosphere with older photo voltaic technology. Are these new lighter panels more susceptible to radiation damage?

The main issue is the highly charged particles trapped by the earth's magnetic field.  The radiation flux is much higher there than outside of the earth's magnetosphere.

[docmordrid]

Some of those thin film solar arrays can also be printed on whatever substrate you want; mylar, plastics, etc, in extremely thin layers. One outfit is approaching an output of 1GW worth of panels a year, and their machine's only working at about 25%.  Definitely a 'next big thing'.

Another possibility is a nuclear-optical converter.  3 layers: nuclear emitter, a monochromatic fluorescent layer and a photoelectric layer tuned to the fluorescent layers output. Bonus points for a reflective layer behind the photoelectric layer so photons get 2 passes at it (like an animals retina for night vision).  Roll 'em up like a cigar if thin or do concentric cylinders if thick. 

[Robotbeat]

Some of those thin film solar arrays can also be printed on whatever substrate you want; mylar, plastics, etc, in extremely thin layers.

Another possibility is a nuclear-optical converter.  3 layers: nuclear emitter, a monochromatic fluorescent layer and a photoelectric layer tuned to the fluorescent layers output. Bonus points for a reflective layer behind the photoelectric layer so photons get 2 passes at it (like an animals retina for night vision).  Roll 'em up like a cigar if thin or do concentric cylinders if thick. 

Both of these are really good ideas.

The first one is cheaper and useful for inner-solar system high-power missions (or perhaps even typical-power missions to Saturn), and is capable of (I've heard) 17000W/kg[/kg], over 50 times greater than high-power nuclear reactors (in other words, your problem is no longer the mass of the power source, but managing a giant array and the mass of the electric thruster itself).

The second idea is useful for a high-specific-power (and high efficiency) replacement of RTGs for outer planets missions. I don't know how well this idea would work for fission, but it can work with decaying beta-emitters.

[ChefPat]

This MSNBC article
http://www.msnbc.msn.com/id/34957156/ns/technology_and_science-space/
Says;
"If we can deploy and gang together modules in low-Earth orbit, you can do it in L1 ... and you are 85 percent of the way to the moon," Bigelow said. In fact, one scenario Bigelow Aerospace has already blueprinted is the soft landing of a trio of attached BA-330 modules — including astronauts — on the moon.

The result: instant moon base, something the size of the International Space Station, Bigelow advised. The self-propelled base could even blast itself into lunar orbit, or move from spot to spot on the moon, he said.


What kind of launch vehicle will be needed to get a BA-330 module to LEO?
Will the propusion/power buss be sent into orbit with the module or will they be sent separately?
If separately how will they be mated?
Once a module is in orbit will it need that VASIMR tug to get to EML-1 or will it be able to do it under it's own power?

This is the configuration that will be assembled at EML-1.

[docmordrid]

What kind of launch vehicle will be needed to get a BA-330 module to LEO?

Anything with a 5+ meter fairing and the ability to put 23,000kg in LEO.  If Wiki's right Delta IV Heavy just makes it at 20,040kg.  Atlas V HLV would work at 25,000kg.  Falcon 9 Heavy certainly would at 32,000kg, with 9,000kg to spare.

Will the propusion/power buss be sent into orbit with the module or will they be sent separately?

MSNBC reported in 2007 that the propulsion bus & node would be launched separately

If separately how will they be mated?

My readings indicate the modules will be remotely controllable like DragonLab

Once a module is in orbit will it need that VASIMR tug to get to EML-1 or will it be able to do it under it's own power?

My bet is that they will need an insertion stage. Looking at the concept art the prop bus, minus the hub, looks to be just short of the length of a BA-330, and it's 45 feet (13.7 m).  Maybe 35 feet. Pretty big for just being an OMS.  Would help if we knew if it's refuelable.

[Rabidpanda]

Anything with a 5+ meter fairing and the ability to put 23,000kg in LEO.  If Wiki's right Delta IV Heavy just makes it at 20,040kg.  Atlas V HLV would work at 25,000kg.  Falcon 9 Heavy certainly would at 32,000kg, with 9,000kg to spare.

Actually Delta IV Heavy does 25,800kg to LEO, Atlas V Heavy does 29,420kg, and Falcon 9 Heavy will only do 29,610kg.

[8900]

Earth surface to LEO:
EELV (Delta 4, Atlas V), Falcon 9, Proton, Ariane 5, H2B, whatever you like
LEO to L1:
chemical propulsion, or ion drive, or VF-xx  low power VASIMR

[docmordrid]

Anything with a 5+ meter fairing and the ability to put 23,000kg in LEO.  If Wiki's right Delta IV Heavy just makes it at 20,040kg.  Atlas V HLV would work at 25,000kg.  Falcon 9 Heavy certainly would at 32,000kg, with 9,000kg to spare.

Actually Delta IV Heavy does 25,800kg to LEO, Atlas V Heavy does 29,420kg, and Falcon 9 Heavy will only do 29,610kg.

Corrected on Atlas V and Delta IV, but SpaceX is now listing the F9H at 32,000 kg.

[mwfair]

The notion of landing an assembled set of modules seems tricky to me.  Perhaps there are advantages, since assembly is harder on the dusty surface, and I guess the mass is not an issue, since the delta v and impulse are the same if the pieces are assembled or landed each individually.  But the controls seem risky, and their impact on the docking rings of each module.