Mass Paradigm

One of the most interesting things to think about with respect to the near-future of space travel is the removal of limited mass as a paradigm. That is to say, right now the predominate design constraint for spacecraft is mass, because rockets are very expensive, so each kilogram of payload must be put to best use. Unfortunately, this means that the design and construction costs for spacecraft are very high, as much effort is put towards shaving off grams by using exotic materials and efficient designs.

But soon the current launch vehicle renaissance will result in launch costs low enough to demolish the limited-mass paradigm. There is a tipping point where it is economical to cut design costs and take the hit on launch costs. There will also see a growing emphasis on tough and reliable systems that last a long time, rather than fragile, light, efficient systems. Combined with lower fuel costs from asteroid mining and improved refueling technologies, the predominant modus operandi will be repairing spacecraft rather than replacing spacecraft. Designing for reusability and, more importantly, refurbishment will be critical.

We’re already seeing a shift towards this paradigm with SpaceX. Their launch vehicles use redundant systems to make up for their cheaper designs — their avionics electronics, for example, are not rad-hardened but instead redundant in triplicate. The mass penalty is minimal, however they also make up for it by using modern electronics concepts. For instance, instead of running numerous copper wires up and down the length of their rockets, they run a single ethernet cable and use a lot of multiplexing.

This kind of change is just the beginning, however. There will be a time when it makes sense to loft a big bundle of steel rods into orbit and have workers weld them into a frame for a spaceship. This has a number of benefits: the frame doesn’t have to be fit into a fairing, it can be reconfigured on the fly, and it doesn’t have to endure the acceleration and acoustic stresses of launch. Additionally, lifting big bundles of steel makes best use of the volume in a launch vehicle fairing.

I think the only two questions about the future of space travel are: How much will it be dominated by robots? and Where will the money come from? But those are questions for another time.

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NASA’s Asteroid Retrieval Mission…

…is actually pretty damn cool. People who are un-enthused by the idea (including many NASA employees) are clearly focusing on the wrong aspect.

Concept of a ARM robotic spacecraft

First, let me give an objective overview of the mission.

“NASA plans to launch the ARM robotic spacecraft at the end of this decade. The agency is working on two concepts for the capture: one would capture an asteroid using an inflatable system, similar to a bag, and the other would capture a boulder off of a much larger asteroid using a robotic arm. The agency will choose one of the two concepts in late 2014.

After an asteroid mass is captured, the spacecraft will redirect it to a stable orbit around the moon called a “Distant Retrograde Orbit.” Astronauts aboard NASA’s Orion spacecraft, launched from a Space Launch System (SLS) rocket, will explore the asteroid in the mid-2020s.”

NASA

So, to summarize: we are going to move a giant space rock from it’s orbit around the sun to an orbit around the moon. A space boulder. We are moving it into orbit around the Moon. Does nobody else think that is a HUGE FUCKING DEAL? The closest thing we’ve ever done is maybe return little grains of dirt from an asteroid. Except this time its an honest-to-god celestial body. That we are moving from one ORBIT to another. Oh, and then I guess we’re sending people to it or something.

Honestly, the manned mission is just shoe-horned in to appease NASA’s mandated directives. The star of the show here is the spacecraft that is moving an asteroid larger than itself (if you don’t count the bag or solar panels — I’m sure the bag can be swapped out for some sort of thermal lance). The advances in electric propulsion and in-space engineering alone will be astounding. Just think of the applications for ISRU (in situ resource utilization) and orbital manufacturing this will provide.

Probes scanning the surface of an asteroid

The ability to drag a study target into an easier-to-reach orbit is stupendous. For one, it means we can send a number of heavier, less expensive unmanned missions to study different aspects of it, with more launch windows and shorter commute times. We can get an extensive profile of the object (even drilling inside), to a level of detail we couldn’t obtain if we were sending a small probe out to the asteroid’s ‘native’ environment.

Having this technology is great for both diverting hazardous asteroids and studying a number of different asteroids at decreased expense. Instead of sending a heavy science probe off using the SLS, we send a re-director up to drag the asteroid close, even into LEO, and then send up a bunch of heavy science probes using cheaper rockets. Alternatively, dragging an asteroid into orbit would be a great opportunity to prototype asteroid-mining techniques.

The point is that if you think putting an asteroid into orbit around the moon is a stupid excuse to use the poorly-thought-out Orion/SLS system, you are absolutely right. An Apollo-style mission architecture doesn’t work for anything beyond a Moon mission, so it’s pointless to think of this mission as “training” for anything. But just because visiting an asteroid with people is stupid doesn’t mean that dragging an asteroid into lunar orbit and visiting it whatsoever is stupid. There is IMMENSE value in an asteroid retrieval mission. Seriously, it’s as exciting as a submarine to Europa or Titan.

5 Things NASA Should Have Never Cancelled

NASA has a long history of cancelling the most exciting and promising projects in its portfolio, instead opting for the safer and less expensive options (which invariably develop ballooning budgets and dismal success records). While I don’t mean to bash the totality of NASA in this post, I do want to lament a few of the best ‘could-have-beens’.

AAP Venus Flyby Schematic

Schematic for the S-IVB wet workshop.

The first is the Venus flyby of the Apollo Applications Program. This would be similar to the Skylab missions, except that instead of launching a pre-built laboratory, the third stage of the Saturn V would be converted into a ‘wet workshop’ living space after using all of its fuel. This would enable the spacecraft to be launched on a trajectory to pass by Venus and then free-return to Earth. I’ll be the first one to point out that manned flybys are not particularly useful scientifically; nonetheless, having the achievement of sending humans into interplanetary space under our belt would be really cool. Then again, being able to say that we’ve ‘already done it’ may have tempered our drive to do it again — much in the way that sending people to the Moon holds less appeal now. For better or for worse, the AAP got dropped along with the rest of the Apollo program in favor of the the Space Shuttle.
 
NERVA mockup

A scale mockup of the NERVA rocket.

In any case, I’ve always believed that the Apollo program took a fundamentally flawed approach to space travel. Instead of scaling up existing technologies, we need to develop more efficient methods that aren’t rooted in the old ‘stick a tin can on an ICBM’ method. This is why the cancellation of NERVA research was so disappointing. NERVA was a nuclear thermal rocket, meaning it used a nuclear reactor to heat up hydrogen propellant. The program was highly successful, and showed great promise in enabling manned missions to Mars without significantly larger rockets than we already had at the time. However, the NERVA program got dragged down with the demise of the Apollo program, and only recently have we seen the rise of a possible replacement technology (electric propulsion).

 

 
But why settle for the 154 ton payload promised by the NERVA-augmented Saturn V? That’s peanuts compared to the 10,000 TONS to LEO made possible through nuclear pulse propulsion. Yes, I’m talking about Project Orion. While, I’ve never been a fan of the concept, I have to admit that 10,000 TONS for (at most) $5 billion is really appealing. Even one such launch would basically make establishing a Mars colony trivial. However, Project Orion never got off the ground (so to speak), because nobody really liked the concept of propelling a spaceship with nuclear bombs. Go figure.

Project Orion Concept Art

One of the longer Orion designs


 
So after Apollo got cancelled and most beyond-Earth projects got trashed, we were left with boring stuff like Single-Stage-To-Orbit completely reusable spacecraft built with off-the-self components. Wait, WHAT?! Yeah, that’s right. In 1985 we had the ability to build a reusable SSTO with almost entirely low-cost commercially-available components.
Delta Clipper Experimental

Sure it looks weird, but it’s awesome!

However, nobody was interested in funding the project. Eventually it got picked up by the DoD’s SDIO (Strategic Defense Initiative Organization), and a team of engineers built a scaled-down version of the craft called the DC-X. It was created to test the concept of a propulsive vertical landing, fast turnaround, and other novel concepts. The project was wildly successful, and showed huge amounts of promise. Perhaps because of this success, it never got much funding, and eventually the SDIO was closed down and NASA reluctantly picked up the DC-X project. With minimal funding and personnel, the DC-X team continued to make fabulous advances and show promise. When the test spacecraft finally had a mishap and caught on fire, NASA refused to front the mere $50 million repair bill, mostly because the DC-X conflicted with their own SSTO project, the X-33.
 
VentureStar size comparison

The VentureStar is one of the fatter spaceplane designs.

Oh yeah, NASA had its own SSTO in development. The X-33 was a suborbital scale version of the proposed VentureStar. The VentureStar was an entirely reusable spaceplane, unlike the Space Shuttle. It launched vertically, landed horizontally, and only used hydrogen-LOX, unlike the Space Shuttle, which required toxic SRBs to get into orbit. The only roadblock to the X-33/VentureStar’s development was the fuel tanks, which were a tricky dual-conic shape. The materials science necessary to construct the fuel tanks was still in its infancy, and so the program got axed (although soon after cancellation, a group of engineers actually constructed a fuel tank which fulfilled all the necessary constraints).

Most of the programs mentioned here were, in one way or another, dropped in favor of the Space Shuttle, which slowly became an embarrassing farce and regrettably set back spaceflight by a good 20-30 years by causing the cancellation of these promising programs. The saddest thing is that we now have the technology to easily solve most of the technical hurdles faced by these programs, but with NASA’s limited budget and vision, we are stuck paddling around LEO with conventional, non-reusable chemical rockets. Even SpaceX’s innovation and drive pales in comparison to the 100% reusable SSTOs mentioned here.

Project Morpheus

I recently discovered an interesting tidbit; NASA has been quietly developing the technology necessary for landing a humanoid robot on the Moon. Now, this is not a particularly interesting goal on its own.

Morpheus lander in flight

However, the point is not the end goal. Project Morpheus, as it is now called, is really an experiment with different work flows. Morpheus is based on the principle of working quickly and efficiently, rather than the slow-and-steady plod that NASA generally adopts. Instead of planning for every possible contingency, the small team is designing low-cost systems with a rapid iteration rate.

The project is also an integration of a number of technologies — methane-oxygen engines, advanced robotics, advanced landing techniques, etc — which are being developed in parallel. Instead of breaking the goal down into small steps and working straight at it, Project M seems to be making more generalized progress, so that the technologies it develops can be used in a variety of applications. This is good, as it will lead to cheaper, faster development cycles for other missions.

Finally, it is not high-profile. Low-profile projects are less likely to get bloated politically and bureaucratically; politicians want to pork-barrel big projects, which leads to missed deadlines and overshot budgets. Keeping projects out of the limelight means they are less likely to get axed for inefficiency, and keeping them low cost means they are less likely to get axed for budgetary reasons.

So I wouldn’t mind if NASA created more of these low-cost, fast-paced projects. Sure, not every one of them would get finished, but the approach is appealing — don’t put all your eggs in one basket, and all that.

On the SLS

NASA has always built its house on political sand, not rock. While they can get lots of funding at the political high-tide, they can also get bogged down to failure. For instance, the ill-fated Space Shuttle program (or STS) was a result of shifting goals and influences on design from disparate sectors.

Similarly, the new Space Launching System (or SLS) is the brainchild of political forces. Its first stage is an extended Space Shuttle External Tank, and its first-stage engines are Space Shuttle Main Engines. Its solid boosters are STS-derived. This means that most of the STS tooling can be kept, and thus constituencies keep their jobs. I have to admit, this re-use reduces design times, but it is not the most efficient way to build a heavy launch vehicle, especially since the technology is more intricate than it needs to be (jacking up production costs).

The SLS is designed to launch the Orion capsule, which was designed as part of the under-funded Constellation program. The Orion spacecraft uses the Apollo architecture, and NASA helps this comparison by painting the SLS with white-and-black roll patterns reminiscent of the famous Saturn V rocket. Combined with the use of STS systems, the SLS threatens to become one big nostalgic mash. Unfortunately for NASA, this means its shortcomings will be overlooked in the future, much like the Space Shuttle program.

For instance, nobody is quite sure what to do with the damn thing after we’ve designed and built it. NASA has recently released that instead of a circum-lunar flyby, the first manned mission of the Orion/SLS will visit an asteroid that will be tugged into orbit around the Moon. After that, everyone seems to throw up their hands and say, “Mars? I guess?”

Criticisms aside, its good that we are developing any sort of heavy-lift manned capacity, because eventually it will enable deep-space missions. I’m just worried that the SLS program isn’t coherent enough to survive shifts in funding or vision. Not that NASA is particularly gifted in either of those departments. With their limited funding, I’m more interested in their robotic missions (or potential thereof — submarine to Europa, anyone?), because any manned program in the near future will consist of paddling around in the metaphorical kiddy pool.

Does Space Exploration have an ROI?

It’s easy to dismiss the current space program as a giant waste of money. Collectively, the world spends billions upon billions of dollars launching tiny pieces of metal into the sky. How could that possibly be better than, say, building a school in India or providing clean water to poor African countries, or even spending it domestically to improve our country? In the face of recent budget crises, this cry gains even more clout.

And indeed, a lot of space programs are very wasteful, especially NASA and the Roscosmos. However, this is generally due to the fact that politicians treat space as a football — another barrel of pork for their constituents. When politics and space exploration mix, you get bloated programs like the Space Shuttle and the new SLS. It’s much better when the politicians set broad goals (AKA land on the moon), fork over the money, and let the engineers work their magic. Otherwise you get a twisted maze of bureaucracy and general management which ends with wasted money and subpar designs.

But let us not forget that NASA has produced a number of very tangible technological advancements, which is summarized here better than I could. In addition, satellites are a cornerstone of the global communications network, not to mention the Global Positioning System, which is satellites. Although communications satellites are now built and launched by commercial ventures, NASA was the first and only customer for a while, and allowed companies to get some expertise in designing and building rockets. Furthermore, the space industry employs tens of thousands of people, all possible because of initial government funding.

However, those examples involve geostationary orbit at the most. What is the practical value of going out and scanning the other bodies in our solar system. Why should we launch space telescopes and space probes? If you don’t believe in the inherent value of knowledge, here is a very down-to-earth example (so to speak): the Solar and Heliospheric Observatory (SOHO) watches the sun 24/7 from L1. It gives us an advance warning for solar flares, allowing satellite operators enough time to turn their expensive pieces of equipment away from the sun, shielding the most delicate electronics from the impending wave of radiation. It is estimated that SOHO has paid for itself 10 times over in this fashion.

Finally, part of space exploration is the attempt to answer some of the big questions. Deep space telescopes answer some part of “Where did we come from?”, and probes to the surfaces of other planets and moon are often trying to answer “Are we alone?”. If you think this is far too sentimental an appeal, I urge you to imagine the ramifications if a future mission to Europa found microorganisms living in the oceans under the ice, or a mission to Mars found lithophiles buried under the Martian regolith. How would world philosophies change?

Regardless, we may be spending too much money and spending it in the wrong places. I submit to you the Indian space program, which designed and launched a mission to Mars for about 75 million dollars. I think the US should follow India’s example and lean towards frugality and very specific, directed goals. Accomplishing a single mission for a small amount of money is better, in my opinion, than developing several high-profile, high-cost programs simultaneously.

While my language and previous post may make it seem like I am opposed to any sort of space exploration, I am merely of the opinion that our society views space exploration in the wrong way. Space exploration should not be about sending humans to other bodies, at least not right now. It should be about trying to find out more about the rest of our solar system, so we can extrapolate and make predictions about the other systems and exoplanets we are discovering. And if all else fails, it can be a platform for many kinds of materials and electronics research.

Say “No” to Manned Spaceflight

I like the idea of people walking around on other planets as much as the next guy, but at the end of the day I can’t go away with a clear conscience without making this point. There is no reason for a manned space program, either now or in the immediate future. In fact, it would be quite irresponsible of us to go mucking around on other balls of dirt.

Much like the archaeologists of the past who used ancient scrolls to keep their fires going, any serious presence or in-situ resource utilization could be inadvertently destroying priceless research subjects. Imagine if we started harvesting ice from asteroids, and then discovered that very old ice tends can contain detailed records of proto-stellar conditions in the Solar System. Even things like rolling robots across Mars or slamming probes into the Moon are calculated risks. We’re pretty sure we won’t mess up anything important, but we aren’t sure. Paradoxically, we can’t be sure what we’re missing without taking some of these risks.

Nonetheless, sending advanced primates to do the job of fast, clean, accurate robots is as irresponsible as it is stupid. Animals are hosts to trillions of bacteria, and if even one strain gets onto the surface of Mars, say, and adapts to the not-so-inhospitable conditions, it’s all over. We rely on the hard vacuum of space to kill off any potential infection vectors on robotic spacecraft, but we can’t do the same for humans. If we’re going to be sending humans to any place remotely capable of developing life, we need to be almost 100% sure there is no life there to begin with, or that the presence of invasive species of bacteria won’t eliminate it.

Even if we make sure to within reasonable doubt that there is no longer or never was life on Mars, we might be screwing ourselves in the long run by sending humans to colonize. If a mutant strain of bacteria spreads to cover the planet like the stromatolites of ancient Earth, and starts eating up what little oxygen is left, then any terraforming efforts could be foiled before they begin. Imagine if our engineered bacteria produces oxygen as a byproduct, and a rogue strain works in the other way. We’d have created a widespread stable ecosystem that leaves us asphyxiating out in the cold.

The two arguments in favor of long-range manned spaceflight have never held much water for me, even if I wanted them to. First, the “putting our eggs in one basket”. Now, current manned spaceflight has nothing to do with the colonization of space. If we were serious about spreading a permanent, self-sustaining presence to another planet, we would have to completely reorganize the existing attitude and institutions surrounding manned spaceflight. Currently, the world’s collective manned spaceflights are a road to nowhere. The ISS is a good sandbox for learning about long-term missions, but we don’t really use it like that.

The second argument is economic. I’ve gone over this is previous posts, but the short of it is that it will be a long time before its profitable to go off-world for resources — unless, that is, there is an exterior source of funding. It’s conceivable that a mild industry might build up around mining space ice for fuel and 3D-printing components. However, at some point funding has to be provided by someone interested in scientific exploration or the intrinsic value of space exploration. A self-contained space economy with Earth as the main buyer is not viable. Perhaps there exists a chicken-egg dilemma: a permanent off-world colony needs industry to survive, and industry needs off-world colonies to thrive.

That’s the cold, hard reality of the matter. I don’t want to have this opinion, but avoiding the truth about manned space exploration isn’t doing anybody any good.

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