NASA's Mars Design Reference Mission

[Northstar1989]

You guys simply MUST read up on the NASA's Mars Design Reference Mission framework... It sounds a lot like something you might do in KSP (with a lot of mods, of course...)

Here's a link to version 3.0 (the latest DRM is 5.0) where they first decided nuclear propulsion was a distinct option:

http://www.wired.com/2014/01/nasas-mars-design-reference-mission-goes-nuclear-2001/

Here is a link to version 5.0, now re-named the "Design Reference Architecture 5.0"

http://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf

I noticed quite a few important changes to the 5.0 plan, such as no longer generating the return fuel from H2 shipped from Earth, and reacting it with Martian CO2 to generate methane; but instead shipping the methane from Earth, and only generating the needed Oxygen from the Martian atmosphere. Apparently they decided the mass-savings on return fuel weren't worth the extra mass and complexity of a Sabatier Reactor (the 5.0 version directly electrolyzes CO2 to produce O2 instead of relying on the Sabatier Reaction)

Regards,

Northstar

Edited May 24, 2014 by Northstar1989

[montyben101]

Cool but one thing: why is there a space shuttle there? are they "planning" (i mean its just an option) to bring it back???

Edit: wait this was a plan in 2001? and was published today?

[Northstar1989]

Cool but one thing: why is there a space shuttle there? are they "planning" (i mean its just an option) to bring it back???

Edit: wait this was a plan in 2001? and was published today?

DRM 3.0 (released in 2001) contained the Shuttle, in a very marginal role (carrying one like crew-ferry to orbit). It was easily removed from the 2008/2009 DRM 5.0

Regards,

Northstar

[Nibb31]

The DRM 5.0 used Constellation assets, which are gone too. Using SLS to launch the crew forces you to launch Orion with at least some other payload module (the hab, the lander or something else), so the launches would have to be rearranged. Inflatables and NTR seem to have fallen out of interest these days, and I doubt the political climate will ever allow nuclear rockets in the foreseeable future. NASA plans are all about solar-electric propulsion these days, so any new DRM would probably incorporate a SEP module with either the DSH or a 10m "Skylab 2" architecture for the hab.

Anyway, there isn't much point in updating these studies, because there certainly isn't any money to implement a 15 year plan like this.

Edited May 24, 2014 by Nibb31

[Northstar1989]

The DRM 5.0 used Constellation assets, which are gone too. Using SLS to launch the crew forces you to launch Orion with at least some other payload module (the hab, the lander or something else), so the launches would have to be rearranged.

Do explain what you mean by this... You realize the architecture for the launch of the payloads was somewhat arbitrary, and already involved in-orbit docking of multi-part ships? It could easily be changed for a lighter (or heavier) launch vehicle- and in fact if you look carefully, you'll see up to an 11-part version for if they had to rely on chemical rockets to get to Mars (lower ISP meant a higher fuel fraction and thus more mass to orbit, which meant more launches...)

I'm not immediately aware, is SLS a heavier or lighter launch vehicle than Constellation? (not that it really matters- if it's lighter, they already have shown they can do it in more launches. If heavier, they don't have to scrub as much mass as they were planning- and can go heavier on things like radiation shielding...)

Inflatables and NTR seem to have fallen out of interest these days, and I doubt the political climate will ever allow nuclear rockets in the foreseeable future. NASA plans are all about solar-electric propulsion these days, so any new DRM would probably incorporate a SEP module with either the DSH or a 10m "Skylab 2" architecture for the hab.

Anyway, there isn't much point in updating these studies, because there certainly isn't any money to implement a 15 year plan like this.

The 5.0 plan explicitly lists a version for Solar Electric Propulsion... Though, to be honest, the standard way of doing it (lots of solar panels on each craft) is horribly inefficient- I can't help but think they would be better off establishing a huge solar-power station in LEO and transmitting the electricity to the ships for their ejection burn via Microwave Phased Beam Power (to heat a thermal receiver, or power the new VASIMR engines currently under final development with an antenna/rectifier), or even from a large nuclear power plant on the ground...

For the return burn, they could have ONE of the craft carry a large detachable section with a lot of solar panels, or a nuclear reactor in an unmanned craft, and deploy a solar or nuclear power satellite around Mars for the same purpose (*IF* they would get more power that way despite the weaker sunlight than deploying the same panels or reactor around Earth, or on Earth's surface, and transmitting to Mars...)

The advantage of this system is that you can use the same panel mass for all the burns, with only a small mass on the other ships for Microwave Wireless Electricity or Microwave Thermal Receivers...

Microwave Power Transmission is not just a technology in KSP Interstellar, you know... It can be done in real life too- and actually in *exactly* the same ways as in KSP-Interstellar... (see the entry about the helicopter with an antenna/rectifier- that technology, scaled up, could provide electricity for a VASIMR engine instead...)

http://en.wikipedia.org/wiki/Beam-powered_propulsion#Microwave_propulsion

Regards,

Northstar

P.S. VASIMR engine are, I assume, the system they were proposing for Solar Electric Propulsion? The multi-megawatt variants are the only human-rated electric engines currently anywhere close to being fully developed... http://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket

Edited May 24, 2014 by Northstar1989

[Nibb31]

I'm not immediately aware, is SLS a heavier or lighter launch vehicle than Constellation?

SLS is actually heavier than Ares V. The problem is that there is no crew-only to LEO configuration like Ares I. To launch a 20 ton Orion alone is a waste, so you have to combine it with a 50 to 70 ton module. So basically, you have to rearrange the assembly of your MTV to suit a different launch vehicle. I'm not saying it's not possible or that it's harder. I'm simply saying that these DRMs are obsolete.

[Northstar1989]

SLS is actually heavier than Ares V. The problem is that there is no crew-only to LEO configuration like Ares I. To launch a 20 ton Orion alone is a waste, so you have to combine it with a 50 to 70 ton module. So basically, you have to rearrange the assembly of your MTV to suit a different launch vehicle. I'm not saying it's not possible or that it's harder. I'm simply saying that these DRMs are obsolete.

Then I guess they'll have to come up with an alternative mission plan- perhaps one with MOAR FUEL TANKS!

(Seriously, though, since radiation exposure is such a big concern, if they brought up more fuel they could make use of a faster transfer orbit. Alternatively, more living space on the cramped transfer vehicle, more science equipment for the Mars mission, more spare equipment and parts for repairs, more radiation shielding for the interplanetary transfer, or a million other things...)

Regards,

Northstar

[shynung]

SLS is actually heavier than Ares V. The problem is that there is no crew-only to LEO configuration like Ares I.

Why did they not use the SRBs as a smaller crew launch vehicle, a la Ares I?

[Nibb31]

Because Ares I was a bad idea. The main reason Constellation was scrapped was because Ares I didn't work.

[Albert VDS]

Launching on an SRB is a bad idea, mainly because in an emergancy you don't want to descent through a cloud of glowing alluminium particles. Parachutes don't work that well when they've got holes burnned in them.

[ScallopPotato]

The DRM 5.0 used Constellation assets, which are gone too. Using SLS to launch the crew forces you to launch Orion with at least some other payload module (the hab, the lander or something else), so the launches would have to be rearranged. Inflatables and NTR seem to have fallen out of interest these days, and I doubt the political climate will ever allow nuclear rockets in the foreseeable future. NASA plans are all about solar-electric propulsion these days, so any new DRM would probably incorporate a SEP module with either the DSH or a 10m "Skylab 2" architecture for the hab.

Anyway, there isn't much point in updating these studies, because there certainly isn't any money to implement a 15 year plan like this.

The various Mars DRMs indicated a need for a 130-140 ton heavy lift vehicle to launch the various components into LEO. Block II of the SLS meets those requirements, especially if the F-1B boosters are selected. I suppose it's possible to launch the crew and the habitat in one launch like the shuttle would do in DRM 3. Otherwise, the habitat and return vehicle could be launched unmanned then the crew gets a lift on a Dragon/Dream Chaser/other commercial craft. How have inflatables fallen out of interest? I haven't seen that happen, especially with Bigelow's progress. Bigelow would definitely be providing the inflatable for both the crew transfer vehicle and the Mars habitat. I know these studies were done before Fuki, but I haven't seen any real opposition to NTRs yet. I'm certain some people will protest, but I could once again reference how the reactors wouldn't be fired up until departure and how an unfired reactor is less radioactive than a RTG.

I am certain that early missions will use SEP, simply because it's available now. I really like the idea of the microwave power to replace the solar panels, but I have a feeling developing such a technology may take more time and effort than simply making NTRs.

I would like to see an update to the study that incorporates the Falcon Heavy, looking at the advantages and challenges of using the cheap 53 ton launch vehicle.

[Nibb31]

The various Mars DRMs indicated a need for a 130-140 ton heavy lift vehicle to launch the various components into LEO. Block II of the SLS meets those requirements, especially if the F-1B boosters are selected. I suppose it's possible to launch the crew and the habitat in one launch like the shuttle would do in DRM 3. Otherwise, the habitat and return vehicle could be launched unmanned then the crew gets a lift on a Dragon/Dream Chaser/other commercial craft. How have inflatables fallen out of interest? I haven't seen that happen, especially with Bigelow's progress. Bigelow would definitely be providing the inflatable for both the crew transfer vehicle and the Mars habitat. I know these studies were done before Fuki, but I haven't seen any real opposition to NTRs yet. I'm certain some people will protest, but I could once again reference how the reactors wouldn't be fired up until departure and how an unfired reactor is less radioactive than a RTG.

I am certain that early missions will use SEP, simply because it's available now. I really like the idea of the microwave power to replace the solar panels, but I have a feeling developing such a technology may take more time and effort than simply making NTRs.

I would like to see an update to the study that incorporates the Falcon Heavy, looking at the advantages and challenges of using the cheap 53 ton launch vehicle.

No DRM will use SpaceX, Bigelow, or DreamChaser. The point of these DRMs is to demonstrate mission architectures using either NASA assets or notional vehicles that are yet to be conceptualized. They are political documents aimed at lawmakers in order to get funding for NASA, not detailed feasibility studies. Demonstrating a DRM that doesn't use SLS and Orion for all phases of the mission goes against that notion.

Additionally, all current plans for SLS exploration missions include SEP tugs and a DSH. There are two concepts for a DSH: either MPLM-based or the Skylab-dry-lab concept. You don't need Bigelow inflatables when you can launch a 10m diameter upper stage in one go.