Kibble

Well there's little reason not to add one, with that lovely Cygnus hardware sitting underutilized and the extra capacity of Atlas V 541 (531 probably doesn't have enough margin to launch Orion, even without Cygnus OM), plus Gemini VII should not be the precedent we base our astronaut's comfort on! I also imagine it would have the toilet and extra supplies and room for six astronauts (IIRC for BEO it carries a nominal 0-4 astronauts) for a few days. Wait does Orion have a toilet? Anyway we should totes build on Cygnus hardware, the OM might even lead to development of a nice Cygnus-derived Lunar Module ascent stage

Oh just flying astronauts and stuff, anything where you just need to get people onto orbit. Like to Station or an assembled interplanetary spacecraft - an alternative to CCTCap for American access to human spaceflight.

So CCTCap is cool and all, and I would love to see (the unfortunately named) Dragon V2 and (the boringly named) CST-100 fly with crew. But in the spirit of the Apollo Applications Project, and Russian incremental improvements on reliable hardware to sustain a near constant human presence in space, this post is meant to propose a few incremental improvements to make on Orion-System hardware for a constant American presence in space for decades to come! My first thought was to make a little more room, with an orbital module so if you're flying with 6 crew on LEO they don't get crowded up. The best (and most obvious) choice is basing it off Cygnus hardware, only with the propulsion bit chopped off, and replaced with whatever docking thing Orion uses. Surprisingly, standard Cygnus is only 1.5mt dry, but it almost triples the habitable volume of Orion! For 1.8mt enhanced Cygnus, you could almost quadruple the volume, but that is probably overkill. The other improvement you can make to optimize for LEO activities is to empty those tanks! Orion has ~1.3km/s delta-vee full, and if we dump most of the fuel, you can cut the service module mass to around 5.337mt. Plus the capsule's 8.913mt, and the orbital module's 1.5mt is 15.75mt. That's under 20 metric tons! About twice the mass of Soyuz, for twice the crew capacity. But System is too overpowered just to launch Orion onto LEO. My original thought was that you could make Slick System by removing the big Shuttle boosters and the Delta upper stage, and adding some Atlas SRMs (or Delta GEMs if they could easily be man-rated). But that still ends up being extremely overpowered. (admirably so, Slick System with 8 Atlas solids can launch 60 whole metric tons to LEO if you offload 29mt of the propellant!) Then I realized 15.75mt was within the payload capacity of the (apparently man-rated) Atlas V rocket family. A likely option is Atlas V 541, which has plenty of margin in payload capacity (17.443mt) to carry the LAS some of the way. Plus, with the 5m diameter fairing, it just wants to launch Orion! There would be an adapter to fit Orion on the top of the fairing, and then they would do Apollo-style transposition, docking, and extraction with the Cygnus OM, which would be sitting attached to Centaur. Here's a bad Photoshop I made of Orion plus Cygnus OM on orbit: And here's a bad Photoshop I made of Orion on Atlas V 541:

How about an adapter/docking tunnel thingy so you can make Excalibur-Almaz with the pressurized ATV part and the VA capsule? Or maybe 3.75m stockalike Orion capsule to go with ATV service module!

Oh I read on wikipedia they were eventually going to launch their OV on this. Maybe thats outdated info D:

The core engines actually don't ignite until just before SRB separation. I think this is the first rocket, and deffi the first manned rocket that's done that.

Is zero boil-off even possible? I was under the impression that even with perfect cooling, hydrogen atoms are small enough to just leak thru the molecules of the tank!

Omg do want

Beautiful RD-170! Beale you make my dreams come true <3

You can avoid almost all of the major problems of a space elevator (tensile strength requiring massive exotic materials, that pesky atmosphere, the climber having to fight gravity, the extreme length, and unworkable taper ratios) by having it just not tethered to the surface. This is called a space tether, but I think the words are backwards, and a space elevator should be any big cable with a climber and junk, but a space tether is one that is attached to the surface - but anyway you can have re-useable single stage launchers that don't have to endure atmospheric reentry, rendezvous with the tether foot in space, and dock and release the payload. Plus the tether can use electrodynamic blah blah to reboost itself. And it doesn't have to use tapered carbon nanotubes, it can probably just be a coilABLE boom. The MXER tether improves this basic design with the amazing Canfield Joint, a special kind of gimbal which can be used to keep the solar panels on the tether pointed at the Sun (without tangling up high-power cables).

Plus coronal mass ejections are the only thing to worry about with radiation - you'll also be exposed to galactic cosmic rays, which aren't just isolated events.

Hey that last image confirms the core and second stage burns oxygen and hydrogen! Too bad it doesn't label the boosters.

Radiation shielding, living space, power (if your capsule doesn't have solar panels, like Apollo), and an advanced, closed-cycle ECLSS. But mostly radiation shielding, because it is so heavy. AFAIK the other stuff isn't that heavy and if you really need extra living space you could just use inflatables or something.

Wow - I had no idea Long March 5 was so...complete! This, and the Tianzhou photos from a couple days ago are really just impressive. Go get space, CNSA!

I actually pictured the taxi as being an expendable capsule. Like it gets launched up (Soyuz-Block D on Proton could probably do it!) rendezvous and docks with Cycler, and stays docked until arrival, where it undocks and makes a minor course correction to enter the planets atmosphere.

You're overestimating how much ballistic correction is required. Using Venus as an example, the Earth-Venus synodic period is almost exactly 8/5 of a year. An Earth-Venus Hohmann period is about 4/5 of a year. Every eight years a cycler will encounter Earth, and 5 months later encounter Venus. With a system of 5 cyclers, one will encounter Earth every 1.6 years. The cyclers will also have beautiful, almost perfect 5-way symmetry! The orbits do not require any major corrections, outside of the gravity assist occurring when the cycler encounters either destination. Minor corrections can be done with low-thrust, high-efficiency ion drives which could function without refueling for decades.

Regular exchange of astronauts to a Mars or Venus base with a cycler is tantalizingly reminiscent of the 6-month expeditions to Space Station!

Don't forget radiation shielding! Apollo or Orion's aluminum walls might be good enough for a journey to the Moon, but in interplanetary space subjected to SEPs, GCRs, and sometimes violent CMEs, you need a bunch of (heavy!) shielding. Accelerating it around all the time is probably not practical. Also IIRC, on (some?) cycler trajectories, the delta vee required for course corrections is small enough that you can use like an ion thruster. If you keep the ECLSS mostly closed-cycle with a Sabatier, all the taxi needs to bring is the crew, some hydrogen gas, and the food for the trip. Maybe. EDIT : And plastic for the onboard 3D printer! :3

That's right, cause they use the thrust of the previous stage as ullage to help ignite the next stage. I really hope we'll get decoupler fairings that are like that in Tantares someday<3

It doesn't take 100-megaton bombs to push something off course. Earth is a small target, and a little delta-vee goes a long way, over long distances. We had 8 Atlas V launches this year, and with the threat of extinction we could probably churn out at least double that, plus the other active launch vehicles capable of sending probes on solar escape trajectories. The closer the asteroid gets, the less each launch pushes it off course though. EDIT : Somebody posted some math! I guess basic impactors won't work as well as I'd assumed.

I think with repeated launches you could set enough impactors on fast solar escape trajectories to redirect even something as massive as Pallas in 4 years. Pioneer 10 was launched March 1972 and got to the Asteroid Belt February 1973 - less than one year! It would be a Cro-Magnon solution, but doable with currently available hardware.

Shame this conversation has devolved into pointless semantics!

There is a benefit to having in-production hardware (especially capable launchers!) lying around even if you have no payloads for them. Otherwise to start something big like a manned lunar landing or whatever the project would include designing both mission-specific hardware, and the system to launch it. And one of the laws of space engineering is any project that includes developing a new launch system, is a launch system project! One that will doubtless get overrun with delays and take billions of dollars. The overhead on keeping System production facilities is worth it, even if it doesn't start regularly flying until decades from now.

Not necessarily. Even the Block I SLS won't be ready until at least 2017, and in that configuration Orion-System can only go on a free-return trajectory around the Moon. Block IB will be more capable, but that requires more hardware - the Exploration Upper Stage - to be designed, qualified, tested, and manufactured. Even then, it would have nowhere to go until the scheduled Exploration Mission 2, the manned exploration of a redirected asteroid, which hasn't even selected a basic mission mode (bag a little one, or pluck a boulder?), much less actually discovered and selected a target, designed, qualified, tested, and manufactured the hardware. That could take years, and then they have to actually fly the redirect mission, which (since its using SEP) will take years more. The quoted 2021 launch is probably extremely optimistic. More likely System will fly EM-1 2017-2019, EM-2 2023-2025. Even then, Block IB System will not be able to support a lunar landing. This will require Block II, which means even more development of new hardware, plus the development and selection of a lunar landing mission mode, and the development of mission-relevant hardware (like the lander). My point is developing new hardware, especially space hardware, especially man-rated space hardware, especially NASA's guidelines, takes a bunch of time and a bunch of money. That's why developing a whole new launch system and capsule and junk is a very bad idea, and expanding and incrementally improving on reliable designs is a very good idea. Russia has been regularly launching R-7 derived rockets since 1957 - thru economic crises, political upheavals, and the transition into an entirely new government.

I actually prefer Energia to N1, especially if its made modular so you can make Zenit, Energia-M, AND Energia - A whole rocket family out of a minimum of parts! Plus it is totes 80s-looking.