Comments on: Random Thoughts: Pre-Depot 2-Launch Manned Missions Using L2 Swingby

By: Jonathan Goff

Jonathan Goff — Thu, 02 Jul 2009 18:53:23 +0000

Dave,
Once you have the L1 or L2 depot, you can pretty much go anywhere with an architecture like this (combined with something like a Bigelow Sundancer module for the living quarters for longer duration flights). I’m not as familiar with NEO trajectories to be honest. It might be possible to use this for an NEO mission pre-depot, but I’m not really sure.

~Jon

By: Xplor

Xplor — Thu, 02 Jul 2009 14:03:01 +0000

NASA has a history of thinking big and wanting everything right from the beginning:
- Operational space shuttle providing airline like flights without any precursor vehicles
- Space Station Freedom providing a huge orbiting laboratory
- Ares V supporting America’s heavy lift needs for the next 30+ years

Shuttle never met expectations; ISS is finally nearing completion 25 years later at over $100B; who knows what our launch requirements will be 20-30 years from now?

Jon, what you are proposing provides a fast, innovative, cost effect path to renewed lunar missions. A sustainable program requires success within politicians short career. And as you stated, there are numerous enhancements that can be made to increase capability or reduce costs.

And arguably the use of depots puts America on a more “Direct” path to Mars than developing an SDLV heavy lift that will continue to tie NASA’s expenditures to a huge albatross called rocket infrastructure rather than allowing NASA to focus on ambitious exploration.

By: dave taht

dave taht — Thu, 02 Jul 2009 05:10:30 +0000

Jon: It would make me happy if you were to apply an analysis like this to the prospect of visiting a near earth asteroid, say, perhaps, one of the Apohole class, or really, anything with a minimal delta-v off of Dr Lance Benner's list. Perhaps a hybrid - manned refuel - instrument mission might make sense for a manned asteroid mission... You save a lot of money and mass on the lander, anyway...

By: Jonathan Goff

Jonathan Goff — Tue, 30 Jun 2009 22:12:15 +0000

Roderick,
An Atlas with dual RD-180s? You mean like their Phase-Two Atlas? Yeah, they’ve been trying to sell that one for a while. Their concept was to use the same tooling diameter as the DIV body (ie going up to ~5.4ish meters diameter) for both the first stage and for the Centaur. Single stick launch vehicle that could put something like 25-30mT into LEO. Me, I think it’s overkill. Any of the Phase 1/2/3 upgrades would make this whole concept a lot easier, but I like the fact that you can still probably do some useful things even without the government explicitly shelling out money for ULA upgrades (if ULA is getting enough demand that they think they can get a better value by investing in those upgrades themselves…that’s a different story).

~Jon

By: Roderick Reilly

Roderick Reilly — Tue, 30 Jun 2009 14:40:50 +0000

A bit OT, but does anyone know if ULA had ever considered a “Fat Atlas,” an “Atlas VI” if you will, that uses two RD-180′s?

By: Rick Boozer

Rick Boozer — Mon, 29 Jun 2009 14:27:57 +0000

Addressing the issue of when the crew transfers to the lunar lander. Is there much fuel penalty if the crew rides up in the command module (for safety’s sake), then does a rendezvous/docking and transfers to the lunar module while in LEO before TLI? If this action is practical, the CM could go on to L2 and the lander to the moon under the scenario that Jon describes and maybe this is what he had in mind.

I like the fact that under Jon’s scheme we have a single stage lunar lander that (theoretically) could be made to be reusable. Unlike the old Apollo or current Constellation plans with separate ascent and descent stages that allow only one use of the lander.

By: Paul Talbot

Paul Talbot — Mon, 29 Jun 2009 12:27:20 +0000

It seems pretty clear to me – the crew transfers to the lander prior to the now uncrewed CM doing the swingby and parking itself at L2. The crew descend to the surface, and then after their stay ascend direct to a rendezvous with the CM at L2, then do a powered swingby on the way home. I’m not sure about abort profiles compared with a CM doing an LOI, though.

By: Anonymous

Anonymous — Mon, 29 Jun 2009 08:08:21 +0000

Jon,

Great post.

It may help you to assume that the SpaceX Dragon capsule is used in your 2-EELV lunar architecture, and that a Falcon-9 Heavy is a launch option as an EELV. It may also help to assume that ULA will build a Delta IV Heavy upper stage with 4 RL-10B engines (and 100,000 lbs thrust) like Aerospace Corp assumed during the Augustine Panel a few weeks ago. This would probably increase performance by 10-tons or so, and ULA could probably easily finance this themselves if ULA were a real company that re-invested to improve its products and if ULA wasn’t a joint-venutre/government-contractor.

The Russian Lunar Mission profile (discussed at the Russian Spaceweb web site) is a similiar 2-EELV approach using dual Lunar Orbit Rendezvous for a 4-man mission. The Russians basically use an Atlas-V Heavy launch vehicle with a 4 RL-10 engine upper-stage called the “Rus-M” for their 2 EELV lunar architecture.

If SpaceX decided to develop and test an LH2 version of their Merlin engine (which their propulsion team had experience doing when working in their previous jobs at TRW and Boeing/Rocketdyne), their Falcon-9 Heavy would have the performance (i.e. over 40-tons to LEO and over 16-tons to Lunar Transfer Orbit) to do a 2-EELV Lunar manned mission with a SpaceX Dragon capsule carrying 4 people. The only thing missing for SpaceX would be a lunar lander built by you at Masten with a ~ 10,000-lb thrust class engine from XCOR or with 4 of your 2,500-lb thrust engines intended for your XA-1.0 vehicle.

By: Jonathan Goff

Jonathan Goff — Mon, 29 Jun 2009 03:27:35 +0000

Hey guys,
I’ll try to work up some cartoons tomorrow to explain what I was thinking (I try not to do rocket stuff on Sundays). Sorry if it wasn’t clear.

~Jon

By: tom cuddihy

tom cuddihy — Mon, 29 Jun 2009 03:19:28 +0000

I really like the idea Jon, except the margin’s probably too small as you said for it to really be feasible –all the downrating for launch profile and LAS that a crewed Atlas V would undergo is what I’m thinking of, not to mention the extra weight of ‘keep alive’ and rendezvous systems the prelaunched LOX tank would require.

But programmatically as an evolutionary idea it’s a perfect “pathway” between what exists now and what some deride as the ‘fantasy’ of a depot. By having the LH2 drop tank already attached to the Centaur, you eliminate a lot of the risk of what most see as the risky parts of a depot, as well as the boiloff concerns for your average depot.

Meanwhile you still have the rendezvous and LOX transfer in orbit to demonstrate the basics of orbital depot technology. From there you’ve proved basically all the mechanics of a depot, it’s just having the will to launch the necessary commercial depot supply train.

Speaking of LOX transfer, where were you thinking that happens physically — I mean physically where would the Delta-delivered LOX depot connect to a stretch Centaur to load LOX once it’s buried in the middle of the launch stack? Were you thinking in the vicinity of the dropped LH2 tank?