Author Topic: Mars Aligned - Ions, Methane, and Exploration  (Read 22872 times)

Offline redliox

  • Senior Member
  • *****
  • Posts: 2541
  • Illinois USA
  • Liked: 684
  • Likes Given: 97
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #40 on: 06/28/2015 09:05 pm »
This is a visual example of the initial robotic elements I dubbed the PCP (Pathfinder Combined Payload).  You can see how the PathSat and PathLander would be linked during transit and how they separate on approach to Mars. 

I had Tea Monster render the PathLander with a ribbed deployable heatshield, kind of like an umbrella.  I suspect an inflatable decelerator would be lighter but also a one-shot deal; I wouldn't expect them to last more than an hour or two after inflation.  Because the PathLander would actually make two entries into the atmosphere, a hybrid shield that's a little more 'firmer' might be better, but then again if an inflatable can be made stable enough to last say 12 hours or so that seems viable.

The PathSat is easier to understand - a big satellite with ion engines.  Cygnus was made a reference because there'd be an option to dock landers for safekeeping to it; a combination of ion drive and gyroscopes would make it a stable platform.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Russel

  • Full Member
  • ****
  • Posts: 1083
  • Liked: 122
  • Likes Given: 4
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #41 on: 06/28/2015 11:03 pm »
I know this has been asked before but how close is the Deimos or Phobs L1 point to the surface and how stable?

I'm thinking about giving the transit vehicle a small amount of ion drive.

Edit: I looked into this. Its about 4 to 5Km. Could even do that with an anchor.
« Last Edit: 06/29/2015 12:05 am by Russel »

Offline Russel

  • Full Member
  • ****
  • Posts: 1083
  • Liked: 122
  • Likes Given: 4
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #42 on: 06/29/2015 12:08 am »
What is Tea Monster?

Offline Russel

  • Full Member
  • ****
  • Posts: 1083
  • Liked: 122
  • Likes Given: 4
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #43 on: 06/29/2015 04:01 pm »
Again, forgive me for being somewhat tangential but I don't feel like starting a whole new thread just yet. I don't quite have the energy right now to write up my architecture in every detail. However I would like to mention where I'm at in case you're interested.

I had a couple of issues with my architecture that amounted to two things. One was to do with having enough fuel on the Mars end of things. And at some point I scaled up the ascent vehicle and that put the squeeze on doing stuff like visiting the moons. The other was that I wasn't particularly happy with the use of SEP, largely for economic reasons, but I hadn't fully defined where it would/could make sense.

I have issues with SEP because of the economics of having massive and expensive vehicles which engage in long mission cycles and the longer the mission cycles the fewer times the investment can be recovered by reuse. This is why I have serious issues with using SEP to get all the way to Mars, and I still do.

However SEP in Earth space, in an environment with higher solar flux and faster mission cycles may make sense and I've hinted at that before. It still depends on cost. If a SEP tug can save 50 tonnes lofted to Low Earth Orbit, then the saving is perhaps going to be under $100M. That's the cost of the launch vehicle plus the cost of the booster that I may have otherwise used. A suitable SEP tug in the order of 500KW to 1MW isn't going to cost $100M. Its going to cost many times more. And the development isn't going to be cheap either. But I think the technology can be gotten to the point where assembly is largely automated. So its in the right ballpark. And we're talking in the order of 6 months or so to raise a 50 tonne payload from Low Earth Orbit to High Earth Orbit. So reuse 20 times is a possibility.

This is not the case for SEP to Mars involving years-long cycles will never see the investment returned. Ok so much for prelude.

What I want to do with my architecture is I'm going to keep the same basic concepts. A transit vehicle that we pair up for long flights and a lander/ascent vehicle. To this add a Xenon/Krypton storage on the transit vehicle and a very limited amount of native ion thrust capability that matches its solar arrays.

There are basically two types of flight. Unmanned and manned. The unmanned flights begin with a transit vehicle (typically loaded with fuel and/or supplies) being put into Low Earth Orbit. The transit vehicle is also the vessel that transfers ion propellant to the waiting SEP tug. The tug now moves the transit vehicle into a high Earth orbit. The final pass close to Earth sees the vehicle use its own thrust (methalox) and then its own internal ion drive capabilities add to the overall delta-V plus course corrections. This should ensure a high percentage of the initial fuel is delivered to Mars. The trajectory chosen is what has been described as a ballistic capture. Which is essentially to minimise the relative velocity at intersection with Mars. A modest level of aerocapture completes the picture. Again this is the unmanned side of things.

Previous this was done with hydrolox boosters. The Earth side SEP tug is simply a device to increase the payload delivered to mars space. That extra payload allows me more freedom to have a more capable ascent vehicle and other luxuries like trips to and from moons. Plus I'm leaving more reserve in low Mars orbit.

Now the manned side of things still happens more conventionally. Two transit vehicles are delivered to Low Earth Orbit. The the crew are sent and the entire system is checked out in Low Earth Orbit. Then two hydrolox boosters are simultaneously delivered and these couple with the transit vehicles and the kick out of Earth space is done by chemical means. Yes I know I could also insert some assistance from the waiting SEP tugs, but time is of the essence here, plus safety of the crew. Once en-route the vehicles will have some ion thrust capability of their own which again contributes to the overall delta-v and provides flexibility and backup.

I won't go into the Mars side of things just now but you get the picture. I'm conceding to SEP for the Earth side boost of all the heavy unmanned stuff. And on the proviso that its possible to build a SEP tug for the purpose for a notional billion or so.

Hope you like :)

Offline kch

  • Full Member
  • ****
  • Posts: 1758
  • Liked: 496
  • Likes Given: 8807
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #44 on: 06/29/2015 04:11 pm »
What is Tea Monster?

Not so much what as who -- one of our fellow posters.  :)

Offline Russel

  • Full Member
  • ****
  • Posts: 1083
  • Liked: 122
  • Likes Given: 4
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #45 on: 06/29/2015 04:45 pm »
What is Tea Monster?

Not so much what as who -- one of our fellow posters.  :)

Ah ok cool. I'm wondering if anyone has any tips on how I could do some simple renders without having to spend the next month learning autocad?

Offline redliox

  • Senior Member
  • *****
  • Posts: 2541
  • Illinois USA
  • Liked: 684
  • Likes Given: 97
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #46 on: 07/03/2015 11:06 am »
The crowning moment in Mars orbit would be visiting the moons.  In this case, being in the higher orbit proximal to synchronous orbit, Deimos would be the prime target of my 'Aligned orbital mission.  Considering the mico-gravity of either moon, landing could be optional for the MTH-ITIT the crew would travel in.  Although they might not "hover" this close to the Martian surface, modest thruster bursts could easily keep the vehicle suspended not to mention relocate to another landing site. 

Most of the exploration would be done by the crew themselves.  While NASA's done a lot of great research into Crew Exploration Vehicles, which essentially mimic the pods from Clarke's 2001: A Space Odyssey, frankly you could just fly the crew with updated Manned Maneuvering Units and use a robotic arm on the 'mothership' to grapple boulders (which might itself be another way to anchor to Deimos/Phobos).

Also this was my favorite of the images Tea Monster drew up for me. :)
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Russel

  • Full Member
  • ****
  • Posts: 1083
  • Liked: 122
  • Likes Given: 4
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #47 on: 07/03/2015 04:36 pm »
As I think I said before, I don't think you can get away with hovering that close. Even with the micro gravity that would require quite a number of Kg (equivalent) of thrust continually.

What would be nice is being close to an L point and dropping an anchor. Of course if you had the crew fly down with an MMU they could take a few Km of tether and attach it to something.

Offline redliox

  • Senior Member
  • *****
  • Posts: 2541
  • Illinois USA
  • Liked: 684
  • Likes Given: 97
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #48 on: 07/03/2015 10:25 pm »
As I think I said before, I don't think you can get away with hovering that close. Even with the micro gravity that would require quite a number of Kg (equivalent) of thrust continually.

What would be nice is being close to an L point and dropping an anchor. Of course if you had the crew fly down with an MMU they could take a few Km of tether and attach it to something.

Correct on the L point being an option, although for lumpy bodies like the Mars moons I doubt they would be particularly stable.  If there has to be a landing it may not be too difficult to arrange.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Russel

  • Full Member
  • ****
  • Posts: 1083
  • Liked: 122
  • Likes Given: 4
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #49 on: 07/05/2015 02:51 pm »
Given its gravitationally locked I think the correct wording is the L point is more unstable than a "normal" L point for spherical bodies, but I suspect its highly predictable.

Other nice thing about Phobos is that Mars itself occupies a large fraction of the sky so at the L point you get additional protection from GCR. Not perfect, but better than out in space.

Its also a great place for stuff like GPS (I guess Deimos would help too) and comms.

Offline redliox

  • Senior Member
  • *****
  • Posts: 2541
  • Illinois USA
  • Liked: 684
  • Likes Given: 97
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #50 on: 07/08/2015 09:52 pm »
This would show how many of the various 'Aligned elements interact in preparation for a Mars landing.  My architecture's crewed components are largely orbital, but the Mars Excursion Vehicle (MEV as you can guess) is decidedly meant for Mars.  As you can further guess, I based it off SpaceX's Dragon 2 although there could be variations including a two-stage setup; personally I opt for a single stage reusable lander.

The MEV would be launched uncrewed and aerobrake into synchronous orbit.  Between flights, it furthermore is nominally docked with the previously launched PathSats in  synchronous orbit for storage.  The robotic arm attached to the MTH, as with the shuttle and ISS arms for vehicles, would grapple MEV and dock it to itself to transfer crew into it.

This shows how there could be a union between orbital and surface vehicles that takes advantage of experience in LEO.  The key is not to overdo orbital architecture heavily, just enough to where it assists what happens on Mars itself.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Ionmars

  • Full Member
  • ****
  • Posts: 1704
  • North Carolina, USA
  • Liked: 666
  • Likes Given: 1822
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #51 on: 07/09/2015 12:15 pm »
...
...
I have issues with SEP because of the economics of having massive and expensive vehicles which engage in long mission cycles and the longer the mission cycles the fewer times the investment can be recovered by reuse. This is why I have serious issues with using SEP to get all the way to Mars, and I still do.

 A suitable SEP tug in the order of 500KW to 1MW isn't going to cost $100M. Its going to cost many times more. And the development isn't going to be cheap either. But I think the technology can be gotten to the point where assembly is largely automated. So its in the right ballpark. And we're talking in the order of 6 months or so to raise a 50 tonne payload from Low Earth Orbit to High Earth Orbit. So reuse 20 times is a possibility.

This is not the case for SEP to Mars involving years-long cycles will never see the investment returned.
...
...
I recently posted on the MCT speculation thread the idea that SpaceX, who are considering SEP in their for their architecture, are also considering an all-propellant option. IMHO the reason for a non-SEP option would be to avoid the high development cost for SEP that you have pointed out.  Have you ever considered an all-propellant option?

One way that SpaceX could avoid SEP is by having the MCT cargo/tanker do double duty. In this scenario BFR is a stage one booster and  MCT (both passenger or cargo versions) would be a second stage to reach LEO using their own propulsion units. A propellant depot in LEO would receive MCT tankers to accumulate fuel and oxidizer in the depot storage tanks.

My idea was that one of the tankers could serve double-duty as a booster for a Mars-bound MCT. A fully-fuelred MCT would attach to a fully-fueled MCT-tanker at the LEO depot. The MCT-tanker would boost both units from LEO to HEO. After separation the Mars-bound MCT would then initiate the TMI burn for a fast transit to Mars and the tanker would return to depot or to Earth for propellant refill.

Are there instances where vehicles in your architecture could serve double-duty in a non-SEP  option?

Offline Russel

  • Full Member
  • ****
  • Posts: 1083
  • Liked: 122
  • Likes Given: 4
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #52 on: 07/09/2015 04:43 pm »
...
...
I have issues with SEP because of the economics of having massive and expensive vehicles which engage in long mission cycles and the longer the mission cycles the fewer times the investment can be recovered by reuse. This is why I have serious issues with using SEP to get all the way to Mars, and I still do.

 A suitable SEP tug in the order of 500KW to 1MW isn't going to cost $100M. Its going to cost many times more. And the development isn't going to be cheap either. But I think the technology can be gotten to the point where assembly is largely automated. So its in the right ballpark. And we're talking in the order of 6 months or so to raise a 50 tonne payload from Low Earth Orbit to High Earth Orbit. So reuse 20 times is a possibility.

This is not the case for SEP to Mars involving years-long cycles will never see the investment returned.
...
...
I recently posted on the MCT speculation thread the idea that SpaceX, who are considering SEP in their for their architecture, are also considering an all-propellant option. IMHO the reason for a non-SEP option would be to avoid the high development cost for SEP that you have pointed out.  Have you ever considered an all-propellant option?

One way that SpaceX could avoid SEP is by having the MCT cargo/tanker do double duty. In this scenario BFR is a stage one booster and  MCT (both passenger or cargo versions) would be a second stage to reach LEO using their own propulsion units. A propellant depot in LEO would receive MCT tankers to accumulate fuel and oxidizer in the depot storage tanks.

My idea was that one of the tankers could serve double-duty as a booster for a Mars-bound MCT. A fully-fuelred MCT would attach to a fully-fueled MCT-tanker at the LEO depot. The MCT-tanker would boost both units from LEO to HEO. After separation the Mars-bound MCT would then initiate the TMI burn for a fast transit to Mars and the tanker would return to depot or to Earth for propellant refill.

Are there instances where vehicles in your architecture could serve double-duty in a non-SEP  option?

Yes, I have considered an all-propellant option :)

Keep the ascent vehicle low mass.
Keep as much mass as possible in high Mars orbit.
Use aerocapture for non-crewed vehicles.

I also have the advantage that my space habitat is actually two separate vehicles that are docked together. Together they provide enough space and comfort for a crew on a long journey. That allows you to separate the vehicles transferring mass to one vehicle and the crew to the other. Meaning the lighter vehicle does the propulsive capture and the non piloted vehicle does the aerocapture.

I also catch up with the return capture back in Earth orbit.

Together these tools save a lot of mass.

Now regarding SEP. My main objection is economic. If you can't reuse the same SEP vehicle many times its probably not worth it. That pretty much rules out sending a large SEP vehicle to Mars, because it takes years to bring back and reuse. There's also the issue that you get less power out near Mars mean an SEP vehicle is less effective for a given size/cost.

I'm not ruling out using SEP as a tug in Earth space on missions measured in months. Such a vehicle has other uses anyhow including managing old satellites, dealing with space junk, etc. So the development work will happen, Mars or not.

Where I see SEP being most useful is in providing the initial lift into near escape orbit and for cargo and fuel.

My mission's workhorse is a "transit vehicle". Its a vehicle, with propulsion, navigation, life support and all the stuff you'd usually expect. It has a fair amount of tankage since its expected to be able to return from high Mars orbit. We're talking tens of tonnes of propellant here. Take such a vehicle, and send it without a crew and you have a tanker.

It also needs some electrical power systems and its own solar array. And in previous iterations I was considering that ion thrusters would be essential for efficient course correction, attitude control, deliberate spinning etc. its only a small jump in logic to have a vehicle that is capable of a modest amount of thrust (we're talking up to 50KW in Earth space).

Given a native SEP capability (with modest extra mass) what you could then do is load the vehicle up with extra tanks, get it up to near escape with a much larger SEP vehicle, and then let it do its own thrusting to complete the task. This wouldn't be suitable for crew (it'd take a couple of years) but for pre-positioning fuel and supplies it might make sense. With each vehicle you could have a "fuel depot" capable of storing around 50 tonnes of fuel.

I actually came at this because I figured it would be nice to actually have a lot of spare capability, so you can do stuff like refuel the lander/ascent vehicle multiple times, have spare lander/ascent vehicles in orbit, be able to do multiple trips to the moons etc.

I still need a different vehicle to do cargo landing on the surface. That vehicle might look rather like what's being proposed in that "minimal mission" by JPL. Just a scaled up MSL heat shield and go direct to retro. Use hypergolics, etc. It might be possible to simply launch one of those landers conventionally with a big chemical booster and expendable upper stage. But it might also be possible to do SEP to high orbit and then build an expendable version of the transit vehicle (methalox fuel, cryogenic storage capability) but without any extraneous mass like life support etc. Just get it up to high orbit then use methalox fuel to boost to Mars. You'd get a high leverage doing it that way. Might even get two or three cargo landers bundled together and pushed with the same vehicle. Beyond that you could go for expendable SEP but be prepared for multiple year transits.


Offline redliox

  • Senior Member
  • *****
  • Posts: 2541
  • Illinois USA
  • Liked: 684
  • Likes Given: 97
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #53 on: 07/10/2015 10:39 am »
...
...
I have issues with SEP because of the economics of having massive and expensive vehicles which engage in long mission cycles and the longer the mission cycles the fewer times the investment can be recovered by reuse. This is why I have serious issues with using SEP to get all the way to Mars, and I still do.

 A suitable SEP tug in the order of 500KW to 1MW isn't going to cost $100M. Its going to cost many times more. And the development isn't going to be cheap either. But I think the technology can be gotten to the point where assembly is largely automated. So its in the right ballpark. And we're talking in the order of 6 months or so to raise a 50 tonne payload from Low Earth Orbit to High Earth Orbit. So reuse 20 times is a possibility.

This is not the case for SEP to Mars involving years-long cycles will never see the investment returned.
...
...
I recently posted on the MCT speculation thread the idea that SpaceX, who are considering SEP in their for their architecture, are also considering an all-propellant option. IMHO the reason for a non-SEP option would be to avoid the high development cost for SEP that you have pointed out.  Have you ever considered an all-propellant option?

One way that SpaceX could avoid SEP is by having the MCT cargo/tanker do double duty. In this scenario BFR is a stage one booster and  MCT (both passenger or cargo versions) would be a second stage to reach LEO using their own propulsion units. A propellant depot in LEO would receive MCT tankers to accumulate fuel and oxidizer in the depot storage tanks.

My idea was that one of the tankers could serve double-duty as a booster for a Mars-bound MCT. A fully-fuelred MCT would attach to a fully-fueled MCT-tanker at the LEO depot. The MCT-tanker would boost both units from LEO to HEO. After separation the Mars-bound MCT would then initiate the TMI burn for a fast transit to Mars and the tanker would return to depot or to Earth for propellant refill.

Are there instances where vehicles in your architecture could serve double-duty in a non-SEP  option?

I believe in the long term there would be outgoing flights sent chemically while incoming flights would arrive via SEP (specifically for crew) or aerocapture (more often for cargo).  If you mean double-duty in a booster acting as a tanker, that makes perfect sense to me since an orbiting, outgoing vehicle would benefit from a swift departure thanks to Martian-made methalox. 

I only argue that such a setup would be for the long-term, not near-term.  NASA is damnably phobic about either aerocapture or ISRU...and that leaves SEP.  SEP's best application would be breaking the crew into orbit, since it would be gentler than aerocapture while still being mass-efficient (albeit requiring sizable solar arrays).  Otherwise locations as far out of gravity wells as possible should be targets, namely EML and areosynchronous orbit, so that SEP doesn't have to fight as hard when it has to be employed on outbound flights.

Most other applications I agree could be done by chemical boosters better (such as utilizing the Oberth effect for Lunar gravity assists); they just tend to be messy in both launch mathematics and space junk.  While SpaceX is making good advances in booster reuse, it's going to be a while yet before we can expect that at Mars.  An injection stage for Earth Departure and Mars Departure are good ideas, but we should limit the number of launchers needed (more specifically for SLS) to get the stuff into orbit as well as minimizing orbital debris piling up at Mars.

Here would be examples of tweaking to 'Aligned to include more chemical boosters within reason:
1) Sending a hypergollic Earth return stage to Mars orbit ahead of the crew
2) Setting up a booster/tanker that fuels on ISRU methalox from Mars, delivers it to orbiting crew vehicles, and speeds them to Earth (much faster than SEP [yes I'd definitely agree there])
3) Utilizing smaller non-SLS launchers to deliver stages more cheaply

I'd remain adamant on keeping the MTH-ITIT in high/synchronous Mars orbit to ensure an easier escape route; also bear in mind the calculated weight I gave to MTH actually includes the equivalent of an Orion SM kick stage; this is meant chiefly for minor course corrections and Deimos maneuvers but likewise it could assist in Phobos operations.  In short, with or without surface methalox the MTH brings some chemical propulsion.  If more is needed, I'd limit it to escaping Earth and Mars respectively.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline redliox

  • Senior Member
  • *****
  • Posts: 2541
  • Illinois USA
  • Liked: 684
  • Likes Given: 97
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #54 on: 10/11/2015 10:19 pm »
In light of the recent NASA Flight to Mars and the Planetary Society's Humans Orbiting Mars, I am going to make a further revision in Mars Aligned that would use 4 SLS launches and 4 FH launches for the initial phases prior to Mars landing.  Reading into both their plans, I felt stupefied that they would think a single mission to Mars would require an average of 12 SLS flights just to orbit the planet and visit Phobos.  I firmly believe the same could be done with fewer rockets (specifically the SLS), and that the same goals could still be met.

The one alteration I am going to make for an orbital 'Aligned mission: inclusion of a hypergolic stage for Phobos/Earth Return.  Coupled with an ITIT tug, I believe it is reasonable to include one such stage to compensate for any shortcomings SEP may have in Mars orbit, enhance the mission to include a Phobos mission, and ensure a departure to Earth from Phobos.

Will be posting the mission plan shortly.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline redliox

  • Senior Member
  • *****
  • Posts: 2541
  • Illinois USA
  • Liked: 684
  • Likes Given: 97
Re: Mars Aligned - Ions, Methane, and Exploration
« Reply #55 on: 10/12/2015 11:19 am »
I'll elaborate on how a chemical stage could be integrated into a orbital-Mars-moons mission.  As every rocket engineer and enthusiast here knows, fuel weight is the key and anchor.  I will start this revival of 'Aligned with a few assumptions that I try to keep within reason:

1) The current plans to reach Martian orbit (The Planetary Society's version http://hom.planetary.org/, NASA's [as posted by our Chris Bergin] http://forum.nasaspaceflight.com/index.php?topic=38417.0 ), which require on average close to a dozen SLS flights per each Mars missions, may have a strong chance to be ruled unwieldy and impractical by policymakers in its current form.  Like all flavors of government pork, a way to trim is likely in order.
2) The logistics of needing so many SLS flights may outstrip production capability; 2 SLS flights yearly should be the most to expect; as such, whenever possible, a crew vehicle that requires SLS lift should be reused and not disposed.
3) If more mass than 2 SLS' can carry is needed, commercial launchers (i.e. Falcon Heavy, perhaps Vulcan) should carry the load, using SEP like ITIT to slowboat to Mars.
3) Landing on Mars is the true priority.  Orbiting Mars is a short stop beforehand.  Bearing this in mind, all orbital (including Phobos) efforts should be consolidated into one reusable vehicle to minimize expense and focus on its use as a Earth Return Vehicle for the Martian landings. (the Phobos habitat isn't planned for much use once the Long-term Mars missions get underway).
4) SEP should carry as much of the propulsive burden as possible, specifically for breaking into high orbit (over both Earth/Mars).  Chemical propulsion is most useful for escaping orbit, especially at Mars, but to fully rely on it (while still tied to Earth) rapidly leads to huge burdens.

I'll introduce the new element to Mars Aligned: MASS - MArs System Stage.  As the name implies, it is a single large booster stage (although not as massive as a fueled SLS upper stage).  General specs:

Mars System Stage - MASS
Dry Mass: 8 metric tons
Wet Mass: 80 metric tons
Propellant: 72 metric tons (N204/MMH - ISP 336)


MASS would launch onboard SLS, dock with an ITIT launched via Falcon Heavy, and the duo slowboat to Mars synchronous orbit.  After putting the hefty MASS in place, the ITIT would return to Earth for potential reuse while MASS remains in orbit, passively maintained by a hull-mounted solar panel and radiator with its hypergolic supply able to sit indefinitely.  Alternatively, MASS could carry methane/oxygen and have an ISP around 360, but the delta-v gain would be less than 200 m/s from such a fuel switch...so for the initial orbital mission hypergolic is the way to go to ensure a fueled rocket.

MASS could serve one of two roles, although not both simultaneously, using a budget of around 1.7 km/s:
A) A complete expedition to Phobos, including altering orbits and returning to synchronous or Deimos orbit.
B) Escape from Mars; while the 1.7 km/s would not instantly put a crewed MTH on an Earth return, this would give a large immediate push toward a more sunward path where the strength of SEP increases and puts the MTH-ITIT on Earth return.

A third potential role, one I normally didn't endorse (as I did for solar electric to begin with), could emerge from the Phobos option: fuel depot.  A spent MASS could be docked to one of the PathSats that would be placed earlier.  They could be stored and refueled either to replay their Phobos role, perform a Mars escape, or remain in place to hold fuel for other functions.

For an orbital mission, this is what I believe is required to launch MASS, MTH, two ITITs, the crewless elements on and orbiting Mars, and the crew themselves:
4 Falcon Heavies
4 Space Launch Systems
In sequence:
Launch Window 1: 2 FH, each carrying a PCP that host the crewless elements for Mars.
Launch Window 2: 2 FH, each carrying an ITIT.  2 SLS, one carrying MASS, one carrying MTH.  MASS-ITIT go to Mars orbit while MTH-ITIT go to EML.
Launch Window 3: 1 SLS, carrying Orion and crew.  After Orion transfers crew to MTH, MTH-ITIT go to Mars orbit.
Launch Window 4: 1 SLS, carrying Orion (with minimal crew if none).  Orion retrieves the returning crew from the MTH-ITIT in EML.

While not a complete solution for the mass problem posed by orbiting Mars, I do believe positioning at least one chemical stage could enhance a predominantly solar-powered-and-propulsed mission.  Moreso, I believe there has to be a far more affordable median between Mars Direct and a NASA Battlestar Galactica redeux.
« Last Edit: 10/12/2015 11:20 am by redliox »
"Let the trails lead where they may, I will follow."
-Tigatron

 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1