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Returning to one spot is a bad thing only if you decide to confine yourself to the one landing during the mission.  Why not make more than one landing?  After all,  unlike the moon,  it's a very long way to Mars and back with men.

GW

NERVA is a 40-year old technology that was a first step toward the upgrade waiting in the wings:  gas core NTR.  Gas core was at the academic lab project stage when NERVA was ready to fly,  and NASA very unwisely cancelled the whole thing.

The best-informed design calculations of the time indicated gas core open cycle had Isp's in the 1000-2500 sec range at engine T/W in the 10-30 range without need for a waste heat radiator.  It appeared regenerative cooling was adequate.  They had bench tested a flow scheme as good as perfect containment,  and they had demonstrated controlled gas-phase fission.  The rest was just technology development in a company lab,  because this was way beyond what academic institutions could handle. 

You look at 2000 sec and you find out that a Buck Rogers-type single stage ship could fly to the moon and back,  at both high payload and high structural fractions.  That was LH2.  Nobody had yet really done a water NERVA,  much less a gas core of any kind.  Water is the really attractive propellant,  because it's "everywhere" and you can refuel to come home.  That ups payload massively. 

Operated above 2500 sec Isp,  a very large waste heat radiator was required.  There was an ill-defined "transparency limit" to reactor power levels somewhere around 10,000 sec.  The design target was a spherical injection scheme operated at 6000 sec,  with an engine system (including radiator) T/W was thought to be near 0.01 to maybe 0.1.  This would have made a very good orbit-to-orbit engine,  with enough vehicle acceleration to be "impulsive" and avoid the long-burn delta-vee losses associated with electric propulsion.  (I don't know,  but I suspect SEP will suffer the same low-acceleration long burn losses. It happens when vehicle acceleration falls below crudely about 0.02 gee.)

That 6000 sec gas core engine was one of three candidates being considered in 1969 for the manned Mars mission actually on-the-books at NASA for 1983.  By the the time the whole thing was cancelled in 1973,  that Mars shot had been pushed back to 1987.  The other two were NERVA and chemical. 

You look at 6000 sec,  and you can go to Mars single stage,  two-way,  at very,  very reasonable mass ratios.  You can even fly very fast:  how about 75 days one-way?  There is enough mass ratio for nice payload and structural fractions.  The structural fractions can cover both the equipment required for cry-storage of propellants long-term,  and for far more structural durability than we have ever used before in a rocket vehicle (except the X-15).  The prospect of a fully reusable ship that could serve for decades,  even centuries,  in space,  thus becomes real. 

These are the "small" applications:  vehicles between a few dozen to a few thousand tons.  Mars,  Venus,  Mercury,  the NEO's,  and maybe,  just maybe the Main Belt could be reached with men using tinkertoys like these. 

For the biggies (which would be needed for planting real colonies anywhere later on) there is nuclear pulse propulsion,  which we already knew in 1959 would actually work.  That set of physics is quite peculiar:  it works better and easier at launch weights above 10,000 tons. 

That kind of ship is not built like anything we have ever seen before.  You build it like a warship,  of heavy steel.  In something resembling a real marine shipyard.  Isp potential is in the 10,000 to 20,000 sec range (at least),  and it is difficult to hold vehicle accelerations under 2 gees.  There are side effects:  fallout and EMP effects.  But it would be worth it to launch maybe half a dozen of these things over about 50 years,  sometime in the not very distant future. 

Propulsion advancement is the real key to just about anything we would ever want to do out there.  The best place to test/develop and maybe base the launch of stuff like that is the moon.  No air and water to pollute,  no neighbors to annoy.  Close enough to reach with what we have right now. 

More wild ideas offered to spark out-of-the-box thinking.  But,  these ideas really are/were supported by the numbers.  These could actually be turned to reality,  if we as a people decided to do it. 

Enjoy!!

GW

Yep.  Sure ain't all science,  either. 

For most outfits,  it's 40% science (written down somewhere),  50% art (learned one-on-one on the job),  and 10% blind dumb luck.  The better outfits (like Spacex now) have higher art %'s to skinny down the blind dumb luck %. 

They didn't start out with enough old hands to have enough art.  That's why Falcon-1 had flight test issues at first.  But they did learn,  and they did fix the art problem.  I'm proud of 'em.  "They done good."

GW

Depots or stacked vehicles,  no difference.  With propellants,  there are storables (like hydrazine and nitrogen tetroxide,  and kerosene),  there are cryogenics (like LOX and liquid methane),  and there are more difficult cryogenics that leak really easily (LH2). 

It would be easy to build a depot or a stack-up vehicle,  out of tank modules full of storables,  all plumbed together.  These would store for many months,  even a few years.  But,  Isp is down under 300 seconds.  No practical way around that. 

Cryogenics like LOX and liquid methane have a boiloff problem,  although it can be mitigated a bunch by a simple sunshade.  But,  again,  Isp is limited to the 300-400 sec range.  Really high-pressure engines with big (vulnerable) bells would fall toward the higher end of the Isp range.  With extra propellant to cover boiloff,  you might get a couple of years storage out of that. 

Hydrogen is the toughie!  It leaks extraordinarily easy,  even right through the metal wall of a tank.  Fittings leak all the time.  And the boiloff problem is much worse.  But LOX-LH2 at high pressure could get you shuttle engine performance or a tad higher:  450-470 sec maybe.  Trouble is,  we still have no really good way to store vast quantities of LH2 for a 2 year mission.  That technology needs a hard look before we fly it to Mars for a round trip with men.  Not that it couldn't be done.  But you're going to need some kind of a cryo-cooler,  and some very stringent leak prevention engineering. 

Or,  maybe store it and ship it as water,  and just make enough hydrogen from that water to support the next burn.  Solar electrolysis module,  perhaps?

Solve that storage problem with LH2,  and not only is LH2-LOX possible for Mars,  so also is LH2 solid core NERVA.  That one was cancelled about a year before first flight,  demonstrating 3/4 hour burns,  restarts,  and 900 sec at T/W 3.6.  That could be done "right now" (see below about resurrecting NERVA).

But,  if we resurrected NERVA,  why not try to do what they didn't do back then,  and do a water NERVA.  In fact,  water contaminated with the other volatiles ammonia and methane.  That stuff is present as ice all over the solar system.  Just mine the ice,  melt it,  filter out the solids,  and use it in your reactor.  That's real simple ISRU,  right there. 

There's an Isp penalty, to be sure,  from MW 16-18 instead of 2,  but I'd bet the higher heat capacity of the water might allow higher reactor power at the same mass throughput,  offsetting some of that Isp penalty.  Think 700 Isp and fuel all over the solar system.  That's an exciting prospect. 

Once you get above the 450 sec level with your Isp at high engine T/W,  mass ratios get far more reasonable at lower stage count.  At 900-100 sec for NERVA,  single stage reusable transit vehicles (orbit-to-orbit) and single-stage reusable "landing boat" vehicles start getting really feasible.  These can be assembled from 25 ton modules in LEO,  and sent anywhere desired. 

We did this NERVA thing before.  We could resurrect it and do it again,  pretty quickly,  I.F.F. (if and only if) the right crowd did this.  (Wrong crowd would take forever.)  It sure makes one whopping difference in one's mission designs. 

The shopping list for enabling and continuing technologies for men in deep space appears to me to be (1) modular vehicle designs docked from 25 ton modules,  (2) some sort of cryocooler for long term LH2 storage,  (3) a sunshade that could double as meteoroid armor,  (4) resurrecting NERVA,  and (5) working on a water NERVA for later upgrades. 

So,  why are they instead doing a gigantic 100-ton launcher when we have some 25 ton launchers already,  and a 53-tonner on a short path to readiness?  Bah,  humbug!  Politics plays too big a role in government space programs.  Ridiculous. 

GW

The compression ratio is important because of product density (largely its pressure).  Material strength need be only what is necessary to contain the product you require.  Most of this chemistry stuff takes place at 1 to several atm.  If 1 atm is good enough,  the compression ratio from 7 mbar to 1013 mbar is about 140,  which is doable in any of several ways. 

Since I last corresponded on this thread,  I found out about an absortion (adsorption?) compressor rig.  You absorb CO2 at 7 mbar,  confine the "sponge",  heat it to drive the CO2 out,  which is near 1 atm.  It's an analog to the confined dry ice vaporization I suggested,  except it works straight off atmospheric CO2.  Works anywhere on Mars.  The product comes out near 1 atm pressure,  which is apparently chemically useful for synthesizing methane from CO2 and water.  No super-high pressures there. 

That'll work,  we just gotta try it enough to work all the bugs out,  before risking depending on it.  Some of that can be done here,  the final check being maybe an unmanned trial on Mars. 

Purity is an issue to be evaluated.  I'm not sure,  but I think this absorption compression thing is the same basic technology that's in the oxygen system in the F-22.  It seems to be having troubles,  and I'd hazard a guess that's a purity-of-product issue.  Mars's atmosphere is not just pure CO2,  so the same risk applies. 

GW

Impaler said somewhere above:

"But with regard to Marshaling we should really be developing the next generation of technologies that both make Marshaling more flexible such as long-term Cryogenic storage, Cryo-propellent transfer, autonomous rendezvous and docking."

I quite agree.  The next upgrade to NERVA ought to be a version that uses water,  contaminated with variable amounts of methane,  ammonia,  and perhaps other volatiles.  I know the Isp is reduced (square root of molecular weight effect),  but propellant availability expands to every object in the solar system with frozen volatiles,  not a small advantage!  Frozen "dirty" water keeps "forever" as long as it is contained and pressurized with 6+ mbar worth of water vapor pressure.  Ice (and liquid water) is very compact and easy to store. 

Perhaps the really high specific heat of liquid water,  and the really high latent heat-of-evaporation of water,  can be used to offset substantially-higher reactor powers,  in order to maintain Isp in the 700-1000 sec range.  I dunno.  Project Rover never really explored that option. 

I'd consider that a follow-on.  The old LH2 NERVA could be quickly resurrected and used "right now".  And should be.

Anything that might work solid core would be easier to do in gas core.  This is true whether open-cycle or "nuclear light bulb".  There's an even better follow-on for you,  although it would take a tad longer to do than a water NERVA. 

GW

PS - don't forget about nuclear explosion propulsion.  Works better the larger the ship.  10^4 -- 10^5 tons,  that's the proper class for pulsed propulsion.

Impaler: 

I quite agree with you.  Leave the transfer habitat in orbit for return.  That provided a huge payoff in Apollo.  Why sacrifice the benefits of "lunar orbit rendezvous" at Mars? 

The lander could be itself the habitat,  as in Apollo.  Or,  maybe not,  if its engines are solid core nuclear,  as in NERVA.  Who yet knows?  Depends upon what we might get operational in the next 5 years or so. 

It would be handy to have at least a small shirtsleeve environment on the surface in which to eat,  sleep,  and do whatever lab work supports "exploration".  That last item is far more important than it might sound,  and is something we did NOT do on Apollo.  That surface habitat could be nothing more than the inflatable version of a Quonset hut.  That engineering problem is not all that hard to solve.

As for rovers,  it's design depends mostly on the size,  mass,  and endurance of the astronaut's spacesuit,  because that is the "payload" for every astronaut being carried.  Why not consider a mechanical counterpressure suit?  They are 2-4 times lighter,  and unbelievably more supple than the "traditional" gas balloon suits we currently use. 

If we were to back off from the arbitrary NASA requirement of 1/3 atm equivalent body compression,  to about 1/5 to 1/4 of an atm,  we could build one today in the lab that worked (we already did,  way,  way back in 1969),  and we could "develop" it to a usable form in about 5 years,  given the "right" contractors. 

A lightweight astronaut/suit requires FAR LESS of a rover,  maybe even one that is unpressurized (just carry an inflatable Quonset hut with you).  Such a thing might even be able to "fly" on rocket engines to very long ranges,  compared to what we are used to thinking about (surface battery cars).  Liquid propellants really do store more energy per unit mass than any battery ever imagined,  so far.

Gotta think way outside the "traditional boxes" to really solve these problems.  There are a few of us (very few) who did that professionally.  From 1976 until 1994,  I did exactly that,  for aerospace/defense applications.  And I was very good at it.  Space travel stuff is really no different. 

That's why I come up with these wild-seeming ideas.  If you look closely,  they might actually work.  Maybe,  they are not really so wild after all. 

GW

Hi Impaler!

Neat to see somebody with a real costing model.  I never had one.  All I did was sum up direct launch costs and use a jigger factor in the 10-30% range for launch/program costs. 

I will say this:  I cheated,  my mission design doesn't quite fit the implied assumptions in your costing model.  You don't have to develop 1000's of tons of new vehicle,  just several dozens worth.  Just a short series of fairly small modules,  and one lander design.

I used a very modular design:  a habitat module (3 closely-related modules,  actually:  same shell,  just a different trick-out inside),  a common propellant module,  and an engine cluster "module".  The crew return was to be two slightly modified Dragons tricked out with extra propellant in the trunk.  The fourth development item was the landing boat vehicle,  which is the toughest of the bunch.  It plus a bunch of propellant modules was the unmanned-asset ship. 

All these modules as I originally worked it out were 30 tons,  and pretty close to the largest payload shroud dimensions for Falcon-Heavy,  although I assumed they would ride up "naked".  The manned and unmanned ships were mostly just a stack-up of a whole bunch of these identical propellant modules all docked together,  then plumbed up and wired.  Given today's projections for Falcon-Heavy,  I'd redesign around 50-53 ton modules,  instead of the 30-ton projection I was using then. 

That's quite a bit different approach as compared to everything we have done before,  but every single piece of it is based on things we have done before.  By the time we would actually start doing it,  Falcon-Heavy and manned Dragon will also fall in the "we've done this before" category. 

GW

Sending unmanned stuff one-way to Mars is no longer particularly expensive.  For one thing,  it is far smaller than any two-way manned vehicle would have to be.  I say the cost is down,  because we are no longer using the shuttle at $1.5B to send max 25 metric tons to LEO.  At max payload,  I calculate about $27,000/pound for shuttle.  (Much higher at part load,  of course.)

The Atlas-5 -551/-552 configurations send 25 metric tons max at near $130M per launch.  That's about $2400/pound.  Delta -4 is comparable payload but about twice as expensive per launch.  Falcon-9 is 10.1 metric tons at about $56M per launch.  That's about $2500/pound at max payload.  Falcon-Heavy is projected to be 53 metric tons max at near $100M per launch.  That's around $900/pound.  These launchers,  used at or near their max payloads,  work out an order of magnitude cheaper,  or more,  compared to shuttle.  These per-pound figures are also much higher,  if the rocket is flown at part load,  too.  So it pays off to fly near max load. 

This is 20-20 hindsight to be sure,  but,  the ISS could have been about 10 times cheaper if we had had these rockets back then!!!  It was built out of 25-ton modules ferried up by shuttle.  Today,  Atlas-5 and Delta-4 could do that,  and Falcon-Heavy could soon do it 3 times cheaper still,  and with bigger modules. 

The necessarily-bigger two-way manned Mars missions could built by docking assembly in LEO the same way ISS was.  But with these newer rockets,  this could be a whole lot cheaper than anyone has ever dared to think in previous years.  By perhaps that same order of magnitude,  or more.  I don't think very many folks realize this yet. 

And,  any such Mars transit-capable vehicle is capable of transits to Venus,  Mercury,  and the NEO's.  You need landers for Mars and Mercury,  but that's a separate problem.  Reusability becomes very practical and financially inviting,  if one starts thinking about orbit-to-orbit transit vehicles (with separate landers as completely-separate transit vehicles),  instead of the more "traditional" Apollo-like approaches. 

GW

Just for the record,  the spinning ship I was proposing was not cable-connected.   It was a stiff structure of docked modules,  of moderately high overall L/D.  Typically,  these ship designs were between 100 and 300 meters long.  They would resemble the "2001" movie's "Discovery" that was spinning end-over-end when it was salvaged in the movie "2010". 

Parallel-stacks of modules could be docked and connected together axially and laterally,  if a single-module stack was too long to be dynamically stable and structurally sound.  No cables,  no fancy space trusses (which do not contain propellant or life support!!!),  no reconfigurations to do anything.  Just spin it up and coast a while (could be thrusters or a flywheel,  not sure which might be lighter,  but either could be made to work right now).  De-spin to make maneuvers,  so the dynamics and control are clean and uncomplicated.  Simple.  Clean.  Very do-able.  Right now. 

The spin rate criterion is a fuzzy boundary.  People with extensive military flight training in high-performance aircraft can tolerate spin rates above 10 rpm for quite a while,  usually.  Not always.  Getting sick from spin is both training-dependent and exposure time-dependent.  The astronaut who can take 12 rpm for an hour in a centrifuge would quite likely get sick,  even incapacitated,  if spun that fast for days,  much less months.  Less training,  lower short-term tolerance,  too,  much less the long-term tolerance.  For "civilians",  4 rpm seems to be tolerable for very long intervals,  typically.  That's why I picked it.  Maybe 2 or 3 is better.  That's an experiment needed to be done right here on Earth right now.  Any of those numbers (2 to 4 rpm) are tolerable in some very practical designs.

I had sizes and numbers worked out for 30 metric ton modules (before Spacex revised it to 53 tons),  with the human vessel powered by a gas core NTR,  as the baseline in my original paper at the Mars Society convention last year in Dallas.  The lander-plus-landing propellant vessels had solid core NTR's which pushed those vessels to Mars,  then got used again as single-stage reusable landing boats fueled from orbit.  These landing boats were 60 ton max weight,  with a 6 ton payload,  at 20% structure,  and 70% LH2 propellant.  These were good for a two-way trip,  fully loaded both ways,  rocket-braking-only descent (no benefit from aerobraking),  and 30-degree out-of-plane both ways. 

I did a revision of this mission design for using solid NTR instead of gas core on the manned ship,  which made it quite a bit larger.  I had to "stage" by leaving several of the empty fuel tanks in LMO,  but still was able to slowboat it two-ways Hohmann transfer without ditching anything at all into deep space.  (The gas core version was a fast-trip at 75 days one way.)  I did this revision because solid core NTR was ready-to-fly in 1973,  while gas core needed some development years.  The right team might get one working in 10-20 years;  the wrong team?  Never. 

I haven't checked it for all-chemical,  but you'd have to stage a lot more by ditching most of the empty tanks into deep space.  But you could still reuse the habitat,  engines,  and those tanks not staged off by the time of return-arrival in LEO.  Myself,  I think the NTR is just a better deal,  especially if maximum re-usability is a design requirement (and it should be from the get-go!!).

Gas core would take longer to develop,  and looks more like a later upgrade to me now.  At high payload fraction,  and simultaneously high structural fraction (for tough-as-an-old-boot reusability),  I rather think the solid core NTR makes more sense,  especially for a single stage lander item.  It is really hard to beat 900-1000 sec Isp to get you practical mass ratios.  I'd love to have a nuclear light bulb gas core at about 1300 sec for the lander,  but that would be some years' worth of development away.  NERVA could be resurrected by the right team in under 5 years.  The gas core in my original paper was a design projection for an open-cycle machine of 6000 sec,  but penalized by a waste heat radiator requirement. 

I've got some illustrations and numerical data for the all-solid core NTR machines worked out and posted over on "exrocketman".  See "Mars Mission Second Thoughts Illustrated" dated 9-6-11.  You'll have to scroll down or navigate down by date and title.  The site is http://exrocketman.blogspot.com

Not only are the performance and size numbers posted,  but the rationales for why I chose what I chose are there.  There's a version of the original paper posted there as well,  dated 7-25-11.  The discussions and rationales  for why maximum self-rescue capability is required,  and why we ought to make multiple landings in the one trip,  are there,  and I think those are very good rationales.  Those are all things we did not do during Apollo,  but we can now,  and we should. 

Too many are still focused on another Apollo-style flag-and-footprints stunt.  That's no reason to go to Mars.  It's just too far,  too dangerous,  and nobody is racing anybody else this time.  Exploration is the real reason to go to Mars.  And that word requires a proper definition,  one based on about 500 years of history. 

GW

What Impaler said in the prior post is very true.  Although,  if one has a smart strategy,  the "slow steady pace" that ensures success doesn't have to be so very slow.  I'm not so sure that most of the current government proposals so far are really that smart of a strategy.  We had the same problem before the Apollo design "gelled".  The key then was lunar orbit rendezvous (using a lander),  which let us do one launch/one mission,  without having to prove orbital assembly in LEO.  That outcome was an artifact of the easier numbers to reach the moon,  relative to the technology of that time.

Since then,  we have proven orbital assembly in LEO by docking:  it's called the ISS,  and we have proven we can build things like that out of 25 ton payloads (what the shuttle could carry).  Can we still do that?  Sure.  We have Atlas-5 -551/552 at 25 tons,  we have Delta -4 in the same class,  and very soon now we will have Spacex Falcon-Heavy at 53 tons.  We're already close with Falcon-9 at 10 tons.  All those are factor 10+/- cheaper than shuttle was.

The numbers for Mars preclude one-launch/one mission.  No one can build a rocket a mile or more high.  That's ridiculous.  The way around that is simple:  orbital assembly in LEO by docking,  as big as you want,  from already-practical payloads in the 20+ ton range.  It's just docked modules plus plumbing and wiring.  How big do you need to build?  We can now build it,  if we choose to,  in any size we want (something not possible in the 1960’s). 

The difference between a max 2-week moon mission and a 2+ year Mars mission with men is life support.  That topic divides into consumables and protection from lethal hazards.  We knew very little about any of that in 1959.

Consumables:  either you build a closed-cycle recycling ecology (which we cannot yet do),  or you provide enough packed supplies to support a botched-up,  stretched-out mission,  oh,  say,  50-100% longer than intended.  The current freeze-dried and/or wrapped-sterilized foods,  that we have been using on Apollo and shuttle and ISS,  only last a year,  maybe 15 months.  That's not long enough.  But,  there's a proven way out:  frozen foods.  They last for decades.  It's just bigger and heavier.  So,  we build a bigger ship in orbit.  No way around that.

Hazards:  zero-gee.  Microgravity illness sets in a bit beyond a year's exposure in forms that are not fully reversible,  and we don't even know the full extent of the scope of these illnesses yet.  The mission is 2+ years.  So,  we must provide artificial gravity,  no way around that.  That has spawned some ridiculously large,  complicated,  and expensive ideas.  We don't need all that.  We've already seen a glimpse of the real answer in the centrifuges we train in.  Just build the assembly in orbit as a long stack with the habitat at one end.  Spin it end-over-end in coast.  Humans can take up to roughly 4 rpm,  and that spin rate only needs a measly 56 m "radius" to provide 1 full gee.  We've already built far larger stuff in space.  We can design it to take all the spin and de-spin forces in the structures.  They’re not that large.

Hazards:  radiation.  Two kinds,  a slow drizzle of super-high energy "cosmic rays" at 24 to 60 REM per year,  depending on the solar cycle.  No shielding is as yet practical,  but we currently allow astronauts to absorb 50 REM a year.  There are career limits that will preclude second trips to Mars,  unless we learn how to shield this stuff effectively.  But,  there’s not much difference between the 60 REM max threat and the 50 REM max limit.  Minimal shielding effects for solar storm particles will make that up difference. 

The second type of radiation is sudden bursts of solar storm particles.  These are events lasting a few hours,  but at radiation exposures like standing in the initial fallout pattern of an atomic bomb: quite quickly lethal.  Shielding is required,  fortunately,  we can already do it,  as these are much lower energy particles.  About 20 cm of water is enough.  So,  provide one place on the ship where all persons can go to shelter,  and surround that space with the water and wastewater tanks you already know you have to have!  If you're really smart,  that shelter is also the flight deck,  so that maneuvers may be flown regardless of the solar weather.

A multi-module habitat and command deck,  some crew return capsules,  a bunch of propellant modules,  and some engines,  all assembled by docking,  could take men from LEO to LMO and back.  Or to Venus.  Or to Mercury.  Or to any of the NEO's.  Same ship.  Build one,  do all those missions with it.  Why launch all that hardware more than once?  Just launch propellant.  Re-use the ship.

OK,  Mars and Mercury need landers,  the other destinations do not.  We're going to need one,  and the Apollo LEM approach is way too inadequate for Mars.  Actually,  IMHO the lander is the true pacing item right now for men to Mars.  Send the landers and all their propellant as a separate ship or ships,  waiting in LMO for the manned ship.  If you're really smart,  you'll use nuclear engines in the lander to build one-stage reusable "landing boats".  That way one mission makes dozens of landings,  not just one.  (Those very nuclear rocket engines all but flew back about 1973,  then got cancelled.)

BTW,  those same nuclear engines can cut the mass of the ship or ships you assemble in Earth orbit,  by a factor near 4.  Hmmmm.  Seems to me like a nuclear rocket engine is a lot more important NASA project than a new giant Saturn-5 class rocket.  We’ve got launch rockets from ULA,  Spacex,  and maybe ATK/EADS big enough already for LEO assembly. 

Yeah we could do this,  and long before the 2030's.

GW

To answer Impaler's question,  yes,  Mark is correct.  There are several really big solid motor applications active.  These include the ICBM's I named,  the submarine-launched BM's,  and all the big strapons used on both Atlas-5 and Delta-4.  ATK and a couple of others build these.  My names might be obsolete,  but ATK used to be Hercules in Utah.  There is also Thiokol in Utah right across the Salt Lake valley from ATK.  Plus,  UTC-CSD had a big motor operation somewhere near the middle of the Mississippi River. 

GW