Friday, December 16, 2011
That's the way NASA sees it anyway. What this actually means is that the partners which are selected - and we're told they desire to select more than one - will be free to pursue their own goals without the burdensome oversight of the growing commercial crew office. It means that companies like SpaceX can design their Dragon capsule to service both NASA's needs and the needs of other companies like the recently announced Statolaunch without asking Mother May I?
I can't wait to see the milestones.
Monday, November 21, 2011
The Circuitous Route To Reuse
Since SpaceX first announced the Falcon 9 they have claimed it is designed to be reusable, but they've yet to demonstrate how. For a number of years the answer has, apparently, been parachutes. Both the successful flights of the Falcon 9 have carried them and for a while we were told they had been deployed. Gwynne Shotwell, speaking at the Space Access conference this year was quoted "We have recovered pieces of the first stages." They were breaking up during re-entry, not giving the parachutes time to deploy.
Most recently, SpaceX has announced with fanfare the new overall approach with pretty graphics and a funky soundtrack. Clearly, they are still a long way away from a working vehicle. I asked Gary Hudson on The Space Show to provide us an educated guess at how fast the Falcon 9 may be going at first stage separation, and at what altitude - the kind of trivial information required to even visualize how such a vehicle could function. He declined.
While it is certainly true that SpaceX's engineers have a lot more information and no doubt have some idea how it is supposed to work, I find it more than a little disconcerting that arguably one of the most seasoned RLV veterans around today isn't able to speculate. At the same time, a new test program dubbed Grasshopper was announced to test vertical takeoff, vertical landing (VTVL) which is a critical part of the new non-parachute approach to reuse.
If that sounds familiar, it should. A subscale VTVL demonstrator has been considered the starting point for this kind of RLV ever since the DC-X program back in the early 1990s. More recently, Armadillo Aerospace and Masten Space Systems have been following this path, with considerably less money to play with. It's 2011 and it seems like SpaceX is starting all over again with reuse.
The Funding Crunch
There's another pathway to reuse: put wings on it. So far, we haven't seen any indication that SpaceX is pursuing that route but, then again, we saw no indication they were pursing VTVL a year ago either. A regularly advocated way to maintain revenue while pursing this route is to woo suborbital markets such as scientific research and tourism. This approach is best exemplified by XCOR and, to a lesser extent Virgin Galactic (as they still seem to have no orbital aspirations). So far, there is no indication that SpaceX is doing that either, but who knows what the future might bring. If the current suborbital providers are successful it may boost investor confidence so much that SpaceX begins to take an interest.
Instead, SpaceX intends to fund their RLV development by selling launch services on the expendable configuration of the Falcon 9. This is good in a number of ways, most notably that it gets into the orbital launch business early, establishing a record of success (hopefully), and has given SpaceX the rocket engine and other components necessary to even start thinking about making a reusable vehicle.
The alternative to both of these paths is to simply have enough up-front funding to buy rocket engines and components from existing providers. For example, the RL-10 from Pratt & Whitney Rocketdyne is considered one of the most reliable rocket engine families available with variants that have been tested rigorously for reuse. Many single-stage to orbit (SSTO) designs of the 1990s just assumed this engine, and the cost, most likely because it was used in the DC-X. SpaceX didn't have this option because their funding was meager by aerospace standards.
The Mars Dream
Elon Musk's plans to send humans to Mars are simply not realistic. Or, at least, that's what I'd say if I had any idea of the details. From all the times I've heard the dream I've managed to garner that basically he's adherent of Bob Zubrin's vision of men braving the perils of space to explore the red planet, with families of immigrants following close behind. This is complete with the heavy lift fetish.
Despite decades of examples that heavy lift can never be cheap, SpaceX has redefined the idea by claiming their upcoming Falcon Heavy launch vehicle will break the $1000/lb barrier and usher in a new age of cheap access to space. The aspirations for even bigger launch vehicles (presumably with even cheaper prices per lb) run deep.
Advocates of staging propellant in orbit, assembling and refueling deep space exploration vehicles which are launched on more modest sized rockets should not be surprised if they find heavy lift advocates counting SpaceX in their camp - but they often are. This defiles the traditional battle lines, with RLV advocates more commonly coming down on the side of propellant depot advocates, if not simply because one of the best uses for an RLV is filling propellant depots with propellants.
As such, it seems that the dream of Mars at SpaceX is essentially Mars Direct with a single heavy lift launch vehicle throwing a Dragon-sized capsule, with stir-crazy explorers, directly to Mars escape velocity. Zubrin has written of such a plan, claiming a Mars landing by 2016 is possible using the Falcon Heavy. It looks good on a cocktail napkin but the same old hand waving is required to shoo away the issues with those pesky human factors like radiation protection and artificial gravity generation.
Practical and profitable space activities are much more effective for exciting public support than dreams of Mars exploration, but it is clear NASA is not going to industrialize space - it threatens the status quo - and today NASA remains SpaceX's greatest customer.
The goal of SpaceX is human spaceflight, and the greatest repository of knowledge about human spaceflight is NASA. As such, it would appear obvious that getting NASA to help you to fly humans safely is a good idea. The way to do that is with Space Act Agreements. This is what SpaceX did under the COTS program, and later under the CCDev program.. and they got paid for the privilege. As a result, the Dragon spacecraft will soon be fully qualified as safe for human habitation on orbit as it will be berthed to the ISS and have astronauts inside it.
The problem is that NASA is a precocious customer. They know what they want, they think they know even better than you do how to make it, and they feel no guilt about changing their mind halfway through the project. As such, Space Act Agreements just totally grind NASA's gears. They don't have enough control.
NASA money is like heroin.. once they start taking it, most people find it very hard to stop. There's a dependence that has grown between NASA and SpaceX, and although it is obviously a love-hate relationship, it's going to be very hard for SpaceX to let go.. but, inevitably, they must. The current needs of NASA are very different to the long term goals of SpaceX.
Promises, Promises, and Delays
SpaceX promises a lot more than they deliver. Over time those promises have changed, with the old promises being forgotten, and new promises being made with more showmanship. Failure is to be expected, with plans changing in response to the lessons learned, but doing so requires clear acknowledgement that there was a failure.
In September this year it was revealed that the second flight of the Falcon 9 had experienced an engine anomaly. While it later became apparent that the issue was minor and not unexpected, the immediate response by the space media was to pounce on what could be a hot story. Quite a number of people I talk to have expressed dismay at the way SpaceX handled the situation, including the lawsuit against Joseph Fragola earlier in the year. While I certainly don't subscribe to the view that SpaceX should be anywhere near as open as NASA with their proprietary information, I do agree that it is indicative of a deeper problem with their engineering culture.
Oh, and we're still waiting for a Falcon 9 flight in 2011.. seems it isn't going to happen.
The Business Case
Now I'd like to talk about the elephant in the room. Fundamentally, SpaceX has a shoddy business case which is best described as a house of cards.. that they're still trying to play poker with.. and there's dogs at the table, and they're smoking cigars! Yeah, metaphor.
The launch business is about volume. If you can get your launch rate up then you can charge less for each launch because the fixed costs will be spread over more launches. SpaceX hasn't done that yet, but they're already charging less than anyone else in the business. This is a common criticism of SpaceX, which most of us in the advocate community love to retort by saying something like: Elon says SpaceX has been profitable every year since 2007!
Okay, that's great. How? There's really only two possible answers: NASA's money, or booking fees. If it is just the former then SpaceX is destined to become just another NASA lackey. So we prefer to think it is the latter - but that means they're living on their seed corn. Eventually they're going to have to actually fly these payloads or give back the deposits. So the acid test will come when SpaceX is called upon to launch and turn a profit in the same year. At that time we will discover if SpaceX is getting the launch rate they require to amortize the fixed costs such that their revenues exceed their expenses. Only then will we know if their prices were realistic.
Suppose they're not. What options does SpaceX have then? Obviously, they can't rise their prices much - that will put them in the same market as the existing providers which have a much better track record (and much better ties to the biggest customers in the government). SpaceX is competing on price, so they will have no choice but to reduce their expenses or increase their flight rate. Reuse is their strategy for doing both of these approaches simultaneously.
There's only one problem: the inherent assumption that there is a market for cheap lift, and that this market can come online fast enough to provide the demand to both amortize their fixed costs and fund their reuse development. In the space community we have a name for this kind of faith: if you build it they will come [no really, watch it!].
If you ask Elon Musk why he is building something which is totally illogical, he will give you the story about the Mars dream. While I don't fully subscribe to the space-based solar power vision, preferring the human tended maintenance of geostationary orbital satellites variety of industrializing space, at least they have some practical idea of what might be economically valuable activities to do in space.
SpaceX is, unquestionably, a bold faced shot in the dark. It is going all-in on the boat hoping that the river will give you a straight flush. It's ballsy madness, and that's why we love them.
Thursday, October 27, 2011
Inspired by the earlier Commercial Orbital Transportation Services program, or "COTS", and funded by the American Recovery and Reinvestment Act of 2009 stimulus to the tune of $50M, CCDev came out swinging in 2010 with five US companies producing impressive results on what was essentially bonus pay to NASA. As such, it was no surprise when a further $270M was provided for the second round, or "CCDev2". This round is now coming to a close, with continuing achievement from US companies with minimal oversight from NASA. Also, a number of "unfunded" CCDev agreements have been made which receive only use of NASA facilities and expertise - they too have been successful.
With all this success, it might seem strange that NASA is dropping the CCDev program - but they are. They intend to move on to a "procurement" process where a number of companies will be required to submit designs, to be reviewed by NASA, with an eventually "down select" to one or possibly two approved providers for the next phase. The Commercial Crew Program, or "CCP", requested funding for the next five years is $850M/year or $4250M total, but at this time it appears unlikely that they will get more than $500M in the first year.
No, that's not a misprint. Here's a graph to hammer home the point.
Why the massive jump? The simple answer is given by acting program director Phil McAlister's comments at the 2011 International Symposium for Personal and Commercial Spaceflight - the commercial crew office has grown to 250 people, many of which are spending their days writing requirements and regulations and have been for "the last two years". In the near future, a number of these staff will be "embedded" into the companies doing their initial design work. This massive increase in oversight comes with a switch from Space Act Agreements - where NASA pays the partner only after agreed upon milestones have been met - to Federal Acquisition Regulation contracts. Although it is increasingly obvious that "partners" are becoming contractors, and NASA is taking control over the industry, McAlister continues to downplay the change, stating that it is "just rhetoric from people who don't want to engage in debate".
Well here's some debate. Fundamentally, the COTS and CCDev rounds were about partnership. NASA was not in control and this was a good thing - for the industry, for NASA and for the taxpayer. Yes, Space Act Agreements have been proven to work, but it's not just about that - it's about who has control in this relationship. Under the COTS/CCDev program, a partner could say no. They could say they weren't interested in pursuing a proposed milestone and NASA had to negotiate. The pay-on-performance standard encouraged partners to only take on milestones they knew they could achieve and, with good faith, NASA had clearly defined. Those milestones represented where the goals of the partner matched the goals of NASA - which many don't seem to understand are necessarily different.
During a congressional testimony today, where Elon Musk was a witness for the first time (see this summary in PopMech), Congressman George Miller (D) asked two questions which insisted that eventually NASA will have just the one provider for commercial crew. Later, Congresswoman Donna Edwards (D) expressed concern that NASA is creating a US monopoly on commercial crew. Setting aside that these people are supposed to be telling NASA what to do, not meekly asking for a forecast of the future, the NASA representative - William Gerstenmaier - essentially agreed with the assessment, stating a lack of funding to support two providers.
Oh, did I not mention that? Yes, NASA thinks nearly five billion dollars isn't sufficient to get commercial crew providers to a point where they can start actually paying them for seats. How much exactly they're going to pay them for seats is anyone's guess. SpaceX will happily tell you that they can do $20M/seat, but that assumes 28 seats per year. Which could mean anything because NASA can't actually tell you how many seats they want. NASA at least wants the price of seats on US commercial crew providers to be below the price of seats on Soyuz, but they seem to have no clue anymore why that is. As such, this has encouraged a number of hilarious Congress-does-math moments where the representative will add together the cost of development, price per seat by estimated number of seats, get a number which is bigger than just continuing to buy seats from the Russians and wonder how this is going to save NASA money. Hint: it's not. That's not the goal. The goal is to kickstart the industry by having NASA as an anchor tenant. The only reason to care about the Soyuz price at all is to ensure the US commercial crew providers are competitive in the international market. This should be obvious but NASA/Congress are stocked with morons.
Here's a prediction.. you heard it here first.. that whole lower-than-Soyuz-price thing will go away real soon. I think this will not be the last way NASA breaks the former-partners making them uncompetitive. Ultimately, the product that NASA wants - the mythical space transportation system that will keep the precious astronauts safe on their purposeless jaunts to "occupy" the ISS, maintaining international relations and supervising ants sorting tiny screws in space - is incompatible with actual productive use of human spaceflight. When the commercial markets fail to materialize, the government can say "we told you so!" and essentially nationalize the industry, as they did with launch vehicles.
Briefly, how was it ever supposed to work? The vision, for those who can remember it, was for NASA to simply buy tickets on commercial crew transportation providers. It was supposed that a promise to buy some number of seats per year would have been enough to encourage private development of the vehicles. This of course was naive, as a promise from NASA is about as bankable as a promise from Congress - that is, worthless. So instead, some money was thrown over the wall with a minimum amount of whatcha-gunna-use-it-for? The hope being that private investment would come to the table. This worked! So the sensible next step is to keep doing the thing that works.
Part II: The Market
What would happen if NASA continued to encourage the industry to develop, instead of embarking on a premature "procurement" process for their own piddling little needs? The answer is glorious: multiple commercial crew transportation providers racing to be the first available to offer seats. Actual price competition and ongoing innovation. This would open new markets and the virtuous cycle would open up the entire frontier.
But... so many people can't remember this vision - if they ever knew it at all. We regularly hear the proud proclamation that the government is the only "market" for human spaceflight. Ok, maybe they're willing to grant that there's a market for a few "overly rich tourists", yes, they really use that word, and maybe there's some other countries that would like to have a space program but don't have the wherewithal to slap together their own big-rocket-and-capsule program, but that's just icing on the cake. Even the commercial crew transportation providers seem to be ignorant of the actual market which is out there waiting to be tapped. Even Elon Musk seems to be ignorant of the real market.. there, I said it. Talk of colonizing Mars someday is great, but that's not where the money is right now.
I can hear the space solar power people screaming from the balcony. They know the answer! And while I appreciate their enthusiasm, I think they're wrong. Someday, space solar power will be operational and human spaceflight to maintain those massive solar arrays will be necessary, but that day is not here. We should keep them firmly in mind and think about their needs when making decisions about on-orbit capabilities, but right now they're still on the ground.
No, the market I'm talking about is the one space market that has consistently made profits since the beginning of the space age. In 2005 PanAmSat launched the Galaxy 15 telecommunications satellite, its ownership was later transferred to Intelsat. In April of 2010 control was lost and the satellite starting drifting, causing significant hazard to other satellites. More importantly, the satellite was out of commission and losing money every day. An estimate of the loss of the satellite, was required for accounting purposes and a figure of around $4194M was given, or ~$400M per year for the expected remaining lifespan.
This gives us some idea of the acceptable price for a satellite "rescue" mission out to geostationary Earth orbit. It's hard to imagine NASA screwing up commercial crew so much that such a mission could be made unaffordable by US suppliers, but if seats are available on the Russian Soyuz - as they will be when NASA finally switches to commercial crew - the inability of US human spaceflight providers to beat the Soyuz price will suddenly become important.
Much more interesting, I think, is to consider the current SpaceX pricetag of a Falcon 9 / crew Dragon flight, upgraded to the Falcon Heavy, and before any of the price reductions promised by reusability.. let's say, $200M. At this price it is not inconceivable to imagine sending a crew out annually to service a number of satellites in a constellation. When we consider that routine maintenance has never been done on communication satellites, it becomes obvious that extended lifetimes can be achieved that would more than offset the cost.
In short, NASA isn't the market for human spaceflight, it isn't even the icing, it's the free frogurt - don't eat it.
Thursday, September 22, 2011
It's the end of civilization.. or so some would have us believe. If they don't get their wish, they intend to take it.. by force. Humanity going into space isn't about leaving them behind, but wouldn't it be nice?
With my most humble apologies to Jeff Greason.
As a follow up I posted this over at kuro5hin.
Tuesday, September 20, 2011
Tuesday, August 30, 2011
Launch to Geostationary Transfer Orbit, circularize using on-board propellant. This is the standard model for how satellites are deployed into space. It is a mature process which has served us well for decades. However, when planning an exploration architecture, it has always been treated as irrelevant.
Here is a list of some current (and one near future) launch vehicles, their listed throw mass to GTO and the calculated mass that can be placed into the first Earth-Moon Lagrange point using a 312 second specific impulse storable propellant thruster (GTO to EML1 delta-v is 1.27 km/s).
|Launch vehicle||Mass to GTO||Mass to EML1|
|Falcon 9||4680 kg||3090 kg|
|H-IIB 304||8000 kg||5282 kg|
|Long March 3B/E||5500 kg||3632 kg|
|Proton||6360 kg||4199 kg|
|Atlas V 551||8700 kg||5745 kg|
|Ariane 5ECA||10050 kg||6636 kg|
|Delta IV-H||12980 kg||8571 kg|
|Falcon Heavy||19000 kg||12546 kg|
What should be obvious is that there is quite a healthy international stable of launch vehicle providers, and they're all geared up for sending payloads to GTO. What is perhaps not obvious is that by going from GTO to EML1 I am seriously cheating myself. I don't mind because throwing to a lunar transfer orbit is something all of these vehicles can also do and, in all cases, the subsequent transfer to EML1 will be less than a transfer from GTO. As such, we can accept the numbers above as accurate, even if they are overly conservative.
So what does this mean? Suppose we want to land a payload on the surface of the Moon. One option is to simply pick the biggest one of these rockets and fly it directly to lunar orbit and start our descent. The total delta-v for such a mission is likely to be about 3.2 km/s, which means we can land a maximum of 6676 kg.
Suppose, instead, we fly to EML1 and pick up fuel. The table above indicates we can put a maximum of 12546 kg to EML1, and the delta-v from EML1 to the lunar surface is 2.52 km/s, so we need 16043 kg of fuel to make the trip. Because we're using storable propellants, this can be delivered over a long time using whichever provider offers the best price, or over a short time by engaging as many providers as become available.
Although this is just a rough analysis, it shows that we can land twice as big payloads by building up EML1 with propellant, without the need for any new launch vehicles, new technologies or even new ways of doing business, and we could start doing it right now.
Saturday, August 13, 2011
There's so many things packed up in this clip. For a start, the House isn't trying to cut the James Web Space Telescope (JWST) because "we don't have the money" or to save money or for any budgetary reason what-so-ever. The House is trying to cut JWST because the Government Accountability Office reported that NASA, and the contractor, have been mismanaging this program. They reported this three different times and required reports on what NASA was going to do about it - NASA didn't provide those reports. The House even said that the reason they were looking to cut JWST was to send a message that ignoring oversight will not be tolerated.
Does that mean the JWST isn't important? No.. no-one is saying that. Everyone agrees that JWST is important and that it will give results of significant scientific discoveries should it ever be completed and launched.. but when will that be? Within a two week period - after the House suggested cutting the budget - the program managers said 2020 or 2018 - neither answer was given in writing. Both answers were contingent upon an increase in their budget.. there's a word we use for declining to increase the budget of mismanaged projects: smart.
So is that the end of JWST? In the minds of NASA-can-do-no-wrong advocates, yes. They immediately declare that you're just not throwing enough money at the problem. It goes something like this: Oh, Hubble was massively overbudget and even broken when it launched. If we hadn't thrown more money at the problem we wouldn't even know about [insert discovery of cosmic significance here].
Meanwhile, the cosmologists are going around saying that the JWST is "essentially complete" or that "we've already built it". This isn't just the sulk cost fallacy, they actually think the JWST is ready and Congress is pulling the rug out from under them. This isn't the case at all, and not even NASA is making this claim. I've been suggesting that, if this were true, people who really want to see JWST fly should be calling for a firm fixed price contract - where the contractor covers the cost overruns, and NASA has less opportunity to screw things up - which has been proven time and time again to result in projects that are completed on-time and under budget.
Failing to mention any of this, Tyson then goes off into one of his standard rants. Oh, we've stopped dreaming. We don't look up. We've turned inwards. Can you imagine why? Hint: it has something to do with NASA mismanagement.
Back in the 1960s people dreamed of going to the Moon. Guess what? NASA went to the Moon. Was NASA not grossly mismanaged back then too? Of course they were, but they were given the mandate to "waste anything but time" and that is one thing government does well: waste.
What did people dream about in the 1970s? Space settlement. These dreams became plans, that wasn't the problem. All the engineering analysis at the time indicated that NASA could do it, so what happened? The plans called for cheap access to space and that requires the opposite of government: efficiency.
Instead, NASA became a government agency focused on "international cooperation", with first the Shuttle-Mir program and later the International Space Station, and while I'm sure there was plenty of people out there dreaming about more cooperation between nations, it had little to do with looking up.
Saturday, August 06, 2011
Now, for some reason, many people who are advocates of propellant depots object to just using existing space storable propellants because that would mean you'd need to launch more mass than if you used cryogenic propellants. Well, so what? More launches - that's a good thing!
We don't need technology development to make propellant depots work. They already work.. we already have one in orbit!
Suppose you want to send 100 tons to Mars transfer orbit. You need either 236 tons of storable propellant or 144 tons of cryogenic propellant (and that's being overly generous to cryogenics). Instead of 5 Falcon Heavy launches you now only need 3. So what? How much is that worth?
So, ya know, NASA has selected companies to study storing cryogenic propellants in space.. and that's great. Technology development, in general, is fantastic and it makes things better in the future. Unfortunately I'm already hearing people say "woohoo! Now we'll have propellant depots and we won't have to waste $38 billion on a heavy lift vehicle to no-where!". Well, no. We already have propellant depots and we already don't need heavy lift to go beyond LEO.
There is, however, a few things that we are in desperate need of.... the political will to go, anywhere, on the government side, and an outspoken willingness to go it alone, if necessary, on the commercial side.
Friday, August 05, 2011
|LEO Station||300 km||273 tons||0.999 g|
|GEO Station||35786 km||30 tons||0.38 g|
Of course, this is a much longer tether than in the film.. but hey, Danny Baldwin is in it - he doesn't make good movies. Anyway, the high station could be an ISS-style module with airlock and docking ports for satellite servicing vehicles. The low station would be a true permanently inhabited facility where people can live for years at a time without fear of bone mass deterioration or the other negative effects of zero gravity. To maximize space we may be tempted to use inflatable Bigelow modules, but we have to consider how they will behave in full gravity.
The only sticking point left is radiation. On the LEO station crews have much less exposure to cosmic radiation thanks to the Earth's magnetic field, however they receive just as much from flying through the South Atlantic Anomaly. As a result, radiation on the GEO station would be 2.19 times as high during solar maximum and 6.568 times as high during solar minimum. If that seems confusing, just remember that the Sun's magnetic field provides most of our protection against cosmic radiation, and it does that more at maximum than at minimum.
One solution may be minimagnetospheres but, again, technology developed for zero-g rarely works unmodified in full gravity. The best solution may simply be appropriate mass. The requirement that the low station be 9.1 times more massive than the high station means that both will have to grow simultaneously but getting mass from LEO to GEO is pretty easy when you have a tether joining the two altitudes.
You may be asking: how plausible is this? Or even: isn't this just the Space Elevator? I estimate it is at least two orders of magnitude easier to do than a space elevator and would only require (vast amounts of) existing tether materials. The cost is most likely dominated by launch costs that should be around $800M in a few years time.
Friday, July 15, 2011
Wednesday, June 22, 2011
Friday, June 10, 2011
According to him, the world consists of the established and successful NASA and the young and inexperienced "New Space Boys" and no-one else. Inexplicably the Boeing corporation exists in both camps.
The "whisper campaign" against Constellation, which no sensible person would deny existed, is absurdly attributed to "New Space Boys" in an effort to rewrite history – it was clearly NASA civil servants, contractors and other malcontents under the DIRECT banner who led that effort, advocating a Shuttle-derived launch vehicle over Griffin's Ares launch family.
If the civil war inside NASA is to be divided into two camps at all, those are the battle lines which have been firmly established. But like all bipolar characterizations, this is also too simplistic.
The enormity of Greg's worldview is just scapegoating – on the current administration and the new entrants into the much maligned space industry. It's a desperate attempt to understand a complex interaction of multiple players with various goals by pointing fingers and crying foul. This kind of worldview can only be maintained by denial of contradiction, such as the Boeing corporation.
Friday, May 27, 2011
Many Moon First advocates are "Mars Next" advocates while most Mars First advocates are "Moon Again?" detractors. The former claim that Mars exploration will benefit from lunar exploration, particularly in experience and risk reduction, and perhaps the procurement of propellant. The latter claim that lunar exploration is just a distraction and want to avoid the risk of being bogged down by another expensive obligation (read: another ISS).
NASA, and the Congress, is hedging their bets.. declining to select a camp and insisting that the so-called flexible path will have "off-ramps" for either lunar or Mars exploration.
Perhaps as a result of the deferment, an old camp has resurfaced with a strong central tenant: the true "spaceship". Defined loosely as a vehicle which is assembled in orbit and is never intended to land on a planetary body - although it may do aerobraking maneuvers in a planetary atmosphere. Spaceship advocates talk about lander vehicles rarely and, although the Moon is recognized as a nice buoy to fly around in a shakedown cruise, the intended destination is clearly Mars.
For many years, this camp has been silenced by a powerful force: The Mars Society and its charismatic leader. With a desire to cut out all distractions, Bob Zubrin has rallied against "Battlestar Galactica scale plans" for getting to Mars, advocating trips of endurance of small crews in tightly packed modules - small enough to fit on the top of a single heavy lift launch vehicle and launched directly from the surface of the Earth to the surface of Mars. What happened?
It seems that the last 20 years of advocating for the simple, elegant, and dangerous Mars Direct plan has been easily swept aside with just a single picture:
This sharp looking spaceship, with its command deck off to the side like the Millennium Falcon, and its inflatable artificial gravity ring promising Bigelow budget sweetness, has inflamed a deep longing for the sci-fi universe we were all promised - humans exploring space for years at a time with large crews.
The problem is propulsion. The tiny Firefly-like cluster on the rear of the ship is woefully inadequate for even the most advanced nuclear thermal propulsion system. The solar panel array is football fields too small for a solar-electric propulsion (or SEP) system. A chemical rocket stage to throw this vehicle to Mars and back would be so much bigger than the vehicle that we'd have trouble seeing it without zooming in... or so I've heard. How true is this objection?
The first problem comes when the objector talks about assembling the spaceship in low Earth orbit. This is an understandable assumption given that all on-orbit assembly to-date has been done in LEO, namely the international space station. However, for some time now the Earth-Moon Lagrangian points have been identified as the perfect location for staging for deep-space missions. This is not to say that no on-orbit assembly would be done in LEO, but once completed the resulting module could be ferried by a SEP tug up to L1. Whereas crew transfer vehicles would take the faster, more energetic path.
Often platforms at the Lagrangian points have been called "gateway stations" and for good reason. It takes less than 1 km/s of delta-v to go from L2 to a Mars transfer orbit. Transiting a large structure from L1 to L2 requires about 100 m/s of delta-v if you need to do it fast, but can be done with just 10 m/s or less if you take your time.
The Moon is so close and lunar water is so abundant that can be cracked into cryogenic propellants or used for radiation shielding, drinking, grow crops, etc. A purely chemical propulsion system quickly becomes feasible, but some other techniques such as solar sailing appear to be very interesting to me.
Although that could be because I just saw the latest Johnny Depp pirate movie. Arrgghh.
Wednesday, May 18, 2011
Saturday, May 07, 2011
Something like the Australian celebrity phenomena happens when people start talking about NASA spinoffs, here's how it works: a speaker creates the implication that civil servant NASA scientists developed some new technology which was subsequently "spun off" to form a commercial product. The most common example of this is Velcro, but there are plenty of others. Whenever you dig into these claims you almost always discover that the entirety of NASA's contribution was in the form of a check. Some people don't even see the deceit in this, suggesting that any NASA funded research is NASA research and therefore any commercial products that result are spinoffs. I've always wondered how the scientists and engineers who do the work to create these products feel about that.
It is an obvious truism that no human-made object could have been placed into space had it not been for the space program of one nation or another. Oh wait, no, that's not a truism at all is it? The first rocket to leave the Earth's atmosphere was a German V2 rocket in 1944, long before anyone had a "space program". Despite this, it seems a lot of well meaning people want to perpetuate the myth that everything in space is a result of the space program.. and a lot of things on Earth too. Watch this short video for my least favorite demonstration:
It disappoints when a speaker says something like this.. it fills you with inspiration for about five seconds, only to have the nagging rational part of your brain chime in with: umm, excuse me? That's not actually true, ya know. I think kids who are inspired by such speakers to follow their dreams will feel terrible betrayal when they eventually discover they've been lied to.
Before anyone accuses me of Tyson bashing, let me say that I'm otherwise a fan of his work and encourage everyone to watch the full 2.5 hour talk. Maybe he doesn't know that NASA didn't invent cordless power drills and their contribution to LASIK eye surgery amounted to writing a check long after it was invented, and maybe he's unaware of the history of the global positioning system and that "space exploration" had nothing to do with it. I don't know, but considering how awesome he is, I find that extremely hard to believe.
But let's take this argument where no-one seems to be willing to go.
We all love the global positioning system - you might say it is the pinnacle of human achievement - surely we should support any program of government spending that can result in fantastic technological marvels becoming such an everyday part of our lives, right? If you don't necessarily agree with that, then perhaps it is because you know the primary justification for building and launching the GPS satellite constellation was global thermonuclear war.
In fact, the development of satellites in general and giant space telescopes in particular, was the cold war need to spy on the Soviet Union. Love the Hubble space telescope? Well then, you should support more government spending on the military industrial complex. Actually, you should long for the days when school children practiced hiding under their desks with visions of nuclear annihilation dancing in their heads. With the Soviet Union gone we'll have to find another enemy but that shouldn't be too hard.
Or - just maybe - you might think that regardless of the spinoffs and the side benefits, it was still bad to have forty years where two great superpowers teetered on the edge of oblivion staring at each other across the void and hoping neither would be so stupid as to make the first move in a game neither side could win.
Similarly, the space program cannot be justified by spinoffs and side benefits. It can't be justified by how many kids are inspired to become scientists and engineers instead of lawyers and doctors - no wait, politicians, yeah that's better. In order to convince your fellow taxpayers that human spaceflight is in the national interest you have to say what it is for and why that is a good thing. We can disagree on what that is, but the last thing we should do is give up and list the side benefits as the actual purpose.. and stop lying to the kids ;)
Saturday, April 30, 2011
With that disclaimer out of the way, what is the legitimate role of government in human spaceflight?
In general, the government should not compete with private industry. For example, if there is domestic production of cars, it is wrong for the government to set up their own car shops. Whatever goal the government is trying to achieve by doing such can almost certainly be better served through regulation or incentives. It's wrong because of the effect it would have on the industry. With the power of the treasury behind it, the government can sell cheaper or invest more in research to make a more attractive product, and while it's true that this would appear to be a public good at first, the resulting elimination in choice as the commercial providers go out of business will inevitably lead to stagnated innovation. Without the profit incentive, all providers fail to respond to consumer demands.
As such, the government should make the fullest use of existing private industry, and encourage the development of more industry that is in the public interest. For example, when launching payloads to orbit, it would be wrong for the government to build their own rocket - or contract someone else to build one for them - if there are already rockets on the market that can serve the purpose. Furthermore, the government should plan their payloads around the capacity that is available and offer incentives for industry to improve their capabilities in the future.
In order to avoid crony capitalism, the government should use competitive bidding and punish price collusion. The government should encourage providers to create products that have customers other than the government and not place unique demands on providers - or at least, such demands should be temporary. When it is in the public interest, the government should allow providers to fail and encourage the healthy functioning of the market.
Ultimately then, what is left for government to do but hand out money to private industry and ensure it is competitive and healthy? Assuming you believe the government should be spending tax dollars, is this just "stimulus" we're talking about?
I think a lot of people see a greater role for government funded human spaceflight than just stimulus. If you agree that government should be involved whenever something is in the public interest but not in the, often short sighted, commercial interest then stimulus is probably enough, but even I see a greater role for government than this.
I often hear claims that human spaceflight is about "research" or "science" that private industry is unable (or unwilling) to do because the return on investment is not immediately apparent. To me, these claims always ring hollow as so much space research is or could be done without humans. Of course, everything I've said thus far could also be applied to robotic spaceflight but it often is already. The situation with human spaceflight seems to be somewhat different.
To me, the goal of human spaceflight has always been obvious. This may surprise some people as I regularly solicit answers to "the why question" and I never seem terribly inspired by the answers I get. The purpose of human spaceflight is to open a new frontier. I have become aware that many people don't know what this means so I will put it more crudely: the purpose of human spaceflight is to find more lands to conquer so that we don't end up weeping like Alexander the Great.
Rather than being uninspiring, some people find this answer outright distasteful. I believe this is because they think of conquering people. So far as we know, the only people in space are the six expedition crew members of the ISS, and no-one is talking about conquering them. I submit that the very first lands which humans occupied, which never before had been occupied, were conquered. I don't know why we can talk about "conquering challenges" but we can't talk about conquering space. It's the same thing, breaking through our limits to increase our sphere of influence.
Space is an especially harsh environment to conquer. It is a grand challenge as JFK described it, but I disagree that this is a reason to do it. To me, that was just a cold war way to say stimulus. The public good created by human spaceflight is the opening of a new frontier. It is a gift of opportunity that we give to the next generation.
Final thought: there are other organizations that reject the commercial interest to act in the public interest. And then we have people like Elon Musk, Bob Bigelow, Jeff Bezos and others, who act both in the commercial interest and in the greater public interest. The frontier doesn't have to be opened by a government space program but, if you've got one, at least give it the right goal.
Sunday, April 17, 2011
In the future, NASA must be prepared to make judgments that will be interpreted as endorsements of particular companies or technical paths serving space markets, such as who receives government assistance and who doesn't. This places NASA in the position of making industrial policy decisions on who gets to develop space infrastructure and resources.
Jesus, really? Up until this point I took the author's constant negative references to partisanship as a distaste to politics and assumed he had no particular leaning, way to yank the veil back dude. Now I have to consider whether not I should finish reading this pinko trash.
Update: Well, I made it to page 139 and after telling us why eliminating aging and the invention of teleporters might have unexpected side-effects (gee, ya think?) Dr Vedda introduces the reader to the travesty of ITAR restrictions as they related to the space industry. He explains that these laws were extended from just guns and bombs to anything that may have a "duel-use" (sic). Ok, so it's just a typo right? If it is, it's one he makes multiple times. I guess the state department is afraid of a return to "satellites at 100 paces" :)
Update: I finished it. Overall I agree with the message of this book: the industrialization of space has and will continue to improve the lives of people on Earth. So if you know someone who has the same political leaning as the author, I'd recommend this book to them.
Tuesday, April 05, 2011
Saturday, March 12, 2011
It seems pretty obvious that we don't currently have the technology to become a spacefaring civilization. Certainly there is stuff in space we could be doing using existing technology, and with great expense, but to really begin the human utilization and colonization of space we need a large variety of technological innovations.
Jon Goff gave a great list of short term technologies that need to be developed before we can really consider society to be spacefaring.
This should be the start of the story.
Wednesday, March 09, 2011
Thursday, February 17, 2011
|Project Management Plan Review and|
Crew Demo 1 System Requirements Review
|Crew Demo 1 System Preliminary Design Review||$22,420,000|
|Crew Demo 2 System Requirements Review||$25,420,000|
|Crew Demo 1 Critical Design Review||$20,420,000|
|Crew Demo 2 System Preliminary Design Review||$20,420,000|
|Crew Demo 1 Demonstration Readiness Review||$20,420,000|
|Crew Demo 3 System Requirements Review||$25,420,000|
|Crew Demo 2 Critical Design Review||$18,420,000|
|Crew Demo 3 System Preliminary Design Review||$20,420,000|
|Crew Demo 1 Mission||$15,420,000|
|Crew Demo 2 Demonstration Readiness Review||$18,420,000|
|Crew Demo 3 Critical Design Review||$18,420,000|
|Crew Demo 2 Mission||$8,420,000|
|Crew Demo 3 Demonstration Readiness Review||$18,420,000|
|Crew Demo 3 Mission||$8,420,000|
As with all the COTS milestones, SpaceX would not have received these payments until the milestone was completed. The finance milestones were required to demonstrate that SpaceX could fund and complete all the milestones without using the payments from NASA as "seed money".
The COTS-D option was never activated. You may even hear some people at NASA say that it was never "funded", this is wrong. The final nail in the coffin of COTS-D came in the form of an intriguing exchange between Sen. Bill Nelson and then acting NASA Administrator Chris Scolese. Here's the relevant part of the long transcript.
Senator Nelson. In last year's authorization bill, there was guidance to NASA about COTS-D Space Act agreements to develop a U.S. commercial alternative to Soyuz. We authorized $150 million in funding for COTS-D. I noticed that you are
putting $150 million of stimulus funds toward the Commercial Crew and Cargo program, but not actually initiating COTS-D agreements. Why are you not initiating these Space Act agreements?
Mr. Scolese. Well, we are working the commercial program as you defined. There was cargo on it. We have those two contracts with SpaceX and Orbital to do cargo. We had one for COTS-D. I cannot recall a specific--$150 million to go on to COTS-D. We did this year in the stimulus identify $150 million to stimulate a commercial activity, and it is broken into two pieces: $70 million to go off and develop capabilities that any visiting vehicle would need, including commercial vehicles, and that includes developing the human space flight rating requirements, the requirements that you need to be certified for human space flight. As you well know, we build human spacecraft and design them so infrequently that we have to write those requirements down. So part of this is to make those available to everybody, make them understandable to everybody, and that will help not only the commercial providers broadly, but all of us. And then $80 million to stimulate activity for a commercial crew.
[recess for a vote]
Senator Nelson. I want to go back to the question that I had asked you earlier. You described the breakdown of how you intend to program $150 million for Commercial Crew and Cargo. Instead of putting the dollars into the various component pieces that would enable crew capability, would it not make more sense just to invest that in a milestone-based demonstration flight?
Mr. Scolese. We discussed that, and we believe that we need to take a measured approach to developing commercial crew. As you know, again it is a very difficult prospect to develop a crewed vehicle to carry crews safely to and from space, let alone rendezvous and dock with the Space Station. So we are working a measured development where we work progressively from developing the capability to get into space, to conduct the rendezvous and docking with the Space Station, to crew rescue, which can be done without having to worry about crew escape,
all the way up to carrying crew. That is the philosophy that we are working to achieve. To do that, we needed to do some things that broadly help the community that wants to do this, as I mentioned earlier, about developing clear and concise specs and standards so that we can safely put our crew on those vehicles. And further, I think you have seen the annual report of the Aerospace Safety Advisory Panel that had some questions about the detail of our human rating requirements. So that is all part of what we are trying to accomplish, and we believe that will get us a commercial crew capability quicker and safer than if we were to just go off and suggest that we fund a capability.
Senator Nelson. But that was not what the legislation said. The legislation said that $150 million was funding for COTS-D. In this case, you would not even have to pay until the COTS-D partner was able to successfully demonstrate that capability. Is that not right?
Mr. Scolese. It would be dependent upon how we structured it. Of course, we wanted to maximize competition for the vehicle. As you know, there is only one COTS-D provider.
Senator Nelson. Well, when I say "you," I am referring to NASA, and you were not the Acting Administrator at the time. This is an example of where NASA has not followed the legislation. Now, let me ask you this. Would $150 million be enough to demonstrate that capability?
Mr. Scolese. We would have to look at it, but I do not think so, sir.
Senator Nelson. Well, what do you think it would be?
Mr. Scolese. I would have to get back to you on that, but it would be several times that, I would expect, because recall, we have to develop not only the crew portion of it. We have to develop the life support systems, the launch escape systems, the recovery systems. All of those have to be developed and demonstrated, and $150 million does not seem enough to do that.
Senator Nelson. We had a unique opportunity, if NASA had listened and followed the law, we had a unique opportunity this year between the 2009 operating plan and the additional funds provided by the stimulus bill and the development of the 2010 budget to craft a COTS-D plan that would have funded the program at the level that the folks needed. That path was not pursued. NASA did not obey the law. Again, I am not saying it to you because you are the Acting Administrator since January 20, but I want to point this out that sometimes NASA does not want itself to be helped. We have got to get our act together.
And that was the last opportunity for COTS-D. Had NASA obeyed the law and provided the $150M that was allocated in the FY09 budget, SpaceX could have started COTS-D and completed the first seven milestones. When the $150M in stimulus money came in SpaceX would have been on much better footing to claim part of it. Instead, Sen Shelby was able to divert $100M to the development of Ares I, a vehicle that was later scheduled to be cancelled prompting him to insert language into law prohibiting NASA from doing that. Of the remaining $50M, SpaceX received none.
The official position of NASA seems to be that the CCDev program has replaced COTS-D. SpaceX has put in a bid for the new round, which NASA has been prohibited from starting due to the failure of Congress to pass a budget for FY11. Should SpaceX be successful, they intend to start work on the launch abort system which will also allow the Dragon spacecraft to land vertically on land. While I have been assured that the CCDev program will be "milestone based" like COTS, I still have my doubts that it will capture the simplicity of the COTS-D option.
Monday, February 14, 2011
Thursday, February 03, 2011
Producing nuclear fusion isn't all that hard. Amateurs regularly cobble together desktop fusion devices like the Farnsworth Fusor and other contraptions. The significant hard problem of fusion is getting more energy out of the device than you put into it. The current government backed effort to achieve this is the ITER project who are building a tokamak style device, but many other schemes are also being tried, with significantly less funding.
One of these is the dense plasma focus of hydrogen/boron fuel, a combination called focus fusion. The technique is relatively easy to understand. You take a metal chamber and put a single tubular electrode in the middle, ringed by a number of solid electrodes. Pump all the air out with a vacuum pump and then add the fuel until it is at a few torr. Dumping about two mega-amps of current into electrodes causes a plasma compression called the "pinch" in which nuclear fusion occurs. The result is a stream of electrons in one direction, a stream of ions in the other direction and a whole lot of x-rays, and virtually no neutrons. These happen to be the perfect products for producing electricity and if that's your goal, it means you can do it very efficiently.
The challenge of focus fusion is getting enough power into the device to burn the fuel - typically done with a big heavy bank of capacitors - and containing that heat in the plasma for long enough. Hydrogen / Boron 11 (or pB11 as it is often called) is the hardest fuel to get fusion going, requiring temperatures over 123 keV. As such, dense plasma focus fusion researchers tend to use deuterium instead, which only requires temperatures of 15 keV. The government program uses deuterium/tritium which only requires 13.6 keV, but tritium is a little hard to come by - it has to be made in nuclear reactors - and is strictly controlled. Deuterium can be picked up in rented bottles from your local gas supplier.
Using a dense plasma focus device to produce deuterium-deuterium fusion is pretty simple and requires minimal startup costs - especially if you do your homework and learn from the mistakes of others. Unlike pB11 fuel, D-D fusion produces neutrons. Shielding fusion researchers from neutron exposure is easily achieved with two things: distance and concrete. Measuring neutron output can be as low tech as looking for bubbles in a contained gel, and as high tech as CCD detection of scintillator stimulation. When you're producing neutrons you know you're achieving fusion.
Getting back to rockets, let's look back up at how I finished my first paragraph describing focus fusion: producing electricity [..] if that's your goal. While nuclear-electric propulsion sure is sexy, what if our goal is just to make a good old nuclear thermal rocket? Back in the 60s the US did a lot of great nuclear-thermal rocket work. They were using highly enriched uranium folded into a solid core with liquid hydrogen running through it. They got specific impulse in the 850 s (vac) range and had plans to achieve higher power before being defunded for obvious political reasons. So what might a nuclear fusion thermal rocket look like?
As our goal is to produce heat, not electricity, it makes more sense to use deuterium as our fuel. We only need to produce pulses of electricity to feed into the electrodes to produce fusion, and the most readily available technology to do that with sufficient power density is a compulsator. Much like an alternator, a compulsator is an electromechanical device that converts mechanical rotation to electrical energy in the form of alternating current. A high power rectifying bridge converts that to direct current to feed into the dense plasma focus. Compulsators have been built for railguns which produce more than enough current (and way more than enough voltage). I haven't read much on reducing pulse width (sometimes called "rise rate") of compulsators, but the ~2 microsecond pulses needed for dense plasma focus does seem challenging.
The rest of the rocket cycle is pretty standard. The expansion nozzle is cooled by cycling the fuel through it, this heats the fuel enough for a state change to occur and the expansion is used to turn a turbine which pumps the fuel, and finally the fuel is used to cool the core. The only difference is that the turbine serves double duty by turning the compulsator. A smart engineer will recognize that the rotors of the compulsator could be the turbine. Similarly, although all three components are shown schematically as being on the same drive, there most likely will be gearing involved to keep the pump constant.
Unlike a device for the production of electricity, the dense plasma focus will probably be made from copper. This will absorb the x-rays and transfer the heat to the "fuel" (aka, the coolant, traditionally the propellant-which-isn't-an-oxidizer of a rocket has been called the fuel). The already slow neutrons will pass right through the copper core and be slowed more by the fuel, hopefully enough that they don't hit the outer chamber with enough velocity to make it irradiated or contribute to wear.
Speaking of fuel, most readers familiar with nuclear thermal rockets have probably been thinking about hydrogen this whole time. Although compulsators are certainly more mass efficient than equivalent capacitors and the means to recharge them, they are not known for being light. As a fusion rocket is incapable of spreading radioactive material into the atmosphere, the traditional safety concerns of launching nuclear thermal rockets from the ground does not apply. As such, propellant density is once again important and a hydrocarbon first stage fusion rocket doesn't need strap-on boosters trumping its inherent safety.
Wednesday, January 26, 2011
1. NO LIMITS. There are no fundamental limits – nor should there be – on the collective human capacity to grow, no matter how growth is defined (which may be in terms of knowledge, wealth, power, population, or morality). Progress is endless (or at least indefinite for all practical purposes).
2. ALL GOOD THINGS GO TOGETHER. Advancements in science and technology, and the resulting mastery over nature, expand our knowledge, wealth, and power, and, in so doing, bring improvements in the moral, political, and spiritual character of the human race. The elements of progress are linked to one another and mutually reinforcing.
3. INNATE DIRECTIONALITY. There exist developmental tendencies, rooted in societal, psychological, or biological mechanisms, that make it far more likely that human civilization will move "upward," toward greater control and understanding of nature and ourselves, rather than “downward” toward chaos and entropy. Progress is, if not inevitable, always highly probable.
In his excellent paper, Reclaiming The Future: Space Advocacy And The Idea Of Progress, Dark proposes that the space program was insulated from the crisis in the idea of progress in the late 60s and because of this, the new pro-space ideology was just a reaction to social change.
To me, this kinda sounds like fearful Americans, desperate to hold on to their beliefs, turning to the only avenue of society where they can still openly talk about the future with a sense of awe and wonder. This may sound harsh, but at least I'm not suggesting it's all just narcissistic phantasy.
Dark has a different explanation for the desperation: the cancellation of Apollo with no plans to follow on with anything else:
The irony was that they embraced this belief at the very moment that the Apollo program was coming to a close, and the future of NASA and space travel becoming increasingly uncertain. Thus, a strong edge of anxiety and urgency was introduced into the writings of space advocates. The means to ensure progress had been found, but would soon be lost forever if government policy was not properly adjusted. This combination of certainty about the path toward redemption alongside anxiety about the possibility of missing a singular opportunity energized the new pro-space literature, and encouraged the growth of an accompanying space advocacy movement.
With the cancellation of the Space Shuttle (and Constellation), that same sense of anxiety and urgency can be felt in today's pro-space literature.. but perhaps that's just because we're all sick of waiting.
My favorite part of Dark's paper comes in the concluding remarks:
If advances in bio-technology, artificial intelligence, and nano-technology allow humanity to prosper on Earth to a greater extent than ever before, the urgency of the space endeavor is lost. In fact, if one has faith that terrestrial technology will continue to advance, the idea of spending billions of dollars on unprofitable space ventures becomes even less attractive.
Why not just wait until new technologies reduce the cost of space flight to reasonable levels? At that point, normal market mechanisms (such as tourist demand) may allow major increases in human space flight without government intervention. But then, of course, no grandiose ideology of progress will be required, any more than such an ideology was required to people the formerly arid deserts of the American southwest once water and air conditioning became widely available.
Oh the sweet bitter irony. Why wouldn't anyone suggest that maybe there are limits to how far terrestrial technology can advance? Why would one assume that the advancement of terrestrial technology would immediately imply that space-going would become any easier? And what would this "faith that terrestrial technology will continue to advance" be called?
I guess you'd call that Progress.
Monday, January 24, 2011
I recently described how to fly to the Moon solo using SpaceX hardware. Someone asked me why I worked out an Apollo 8 style flight and didn't just do a simple free return trajectory.. after all, it's a lot easier - and that's actually the reason - it's too dog gone easy. In order to make this interesting I decided to try to think of the easiest way to do a free return trajectory. Preferably, we'd like to use an unmodified spacecraft and launch vehicle and not have to develop any other hardware.
For a start, let's forget this whole idea of an Earth Departure Stage - we'll just throw the Dragon spacecraft to lunar orbit. This sure is simple, but it only gives us 2585 kg to work with. This prompts the question, exactly what is the mass of an unladen Dragon.. yeah, yeah, I know - African or European?
Looking at the Falcon 9 Users Guide we find that it can throw 9358 kg to 51.6º with an altitude of 400 km. SpaceX will happily tell you that the Dragon can carry 3000 kg of pressurized cargo and 3000 kg of unpressurized cargo to the ISS, and has 1290 kg of propellant. So the dry mass has to be around 2068 kg. It's this big number that prompted me to suggest pulling out the heavy docking adapter, etc, but we're not doing that this time.
At some point there is going to be a bunch of used Dragon capsules, and maybe we can get one for cheap. The actual launch is around $56 million, if you can get SpaceX to stop placating NASA's worst fears: another crew lost and everyone asking why the hell they were flying in the first place. If they keep blowing money on a fancy launch abort system, then who knows.. but it'll probably still be smaller than the $150M per seat that Space Adventures is charging for a ride on Russian hardware.
For a single crew member weighing a maximum of 100 kg, you need 11.839 kg of cabin air, 25.83kg oxygen candles, 52.71kg LiHo CO2 scrubbers, and 45kg food and water. Total is 235.379 kg. From our throw mass to lunar transfer orbit we subtract the dry mass and the consumable mass to find 281 kg remaining.
Remember how we took the fuel out of the Dragon? Let's put 245 kg back. This gives us about 300 m/s of delta-v, which is about 10 times as much delta-v as we need to do a free return trajectory. So even if you're flying like Scott Carpenter you should be able to pull it off.
The remaining 36 kg is margin.. or you could take your dog along for the ride.
I have one last thing to say on this insanity. For a while I've been using 3140 m/s as the required delta-v to from Lunar Transfer Orbit directly to the surface of the Moon. Apparently, this estimate is horrible. According to the Lunar Polar Volatiles Explorer concept mission the required delta-v post-TLI breaks down like this:
|Thermal Control Maneuvers||70|
|Landing Site Navigation||25|
For some inexplicable reason they do the breaking burn with a solid rocket motor with 292 seconds of isp. Their maneuvering thrusters have 272 isp, and the terminal descent is done with 296 isp. With this reduced performance they turn 3492 kg at TLI into 1203 kg on the lunar surface.
They get the wet mass there by flying an Atlas V 401 on a 5 day minimum delta-v maneuver, and although that's just fine for cargo, it just means more consumables and radiation exposure for a human. The Falcon 9 has higher mass to LEO, but lower mass to GEO, but it's also 1/3rd the price, so let's stick with the 2585 kg that a Falcon 9 can throw direct to Lunar Transfer Orbit and use a decent storable propellant isp of 312 seconds. With that we can deliver 1038 kg to the surface.
With a inert mass ratio of 0.15 for the lander, the total payload mass is 651 kg. Using the crew/consumable mass above, and assuming 2.5 days to get there, we can spend 28 days on the lunar surface. Or you could try to fit in propellant to fly back.. I guess, if you wanna die in your bed or something.
The Gravity Loading Countermeasure Skinsuit (yes, that's Richard Garriott) and Mini-Magnetosphere Radiation Shielding are two technologies which, if successful, will change the way you think about space exploration and eventually even colonization. They address the two fundamental stumbling blocks of long term missions in space: the negative health affects of zero-g and radiation exposure.
Zero-G Skinsuits exert a force on the wearer's body which duplicates the loading on the skeleton that gravity usually provides. The expectation is that Skinsuits will reduce or eliminate the deleterious bone loss that astronauts currently experience in zero-g. So far, the prototypes have only been tested on parabolic flights, although they are similar to the Russian penguin suits which were used by cosmonauts on MIR (unfortunately with little to no reported results - as is typical of Russian space medicine).
Should Skinsuits turn out to be effective at eliminating bone loss, and possibly even have some positive effect on muscle loss, this finding will render other technologies aimed at addressing the problem less important. Specifically, solutions aimed at getting astronauts to Mars as quickly as possible will be less important. Artificial gravity generation for long trips or even for space colony designs will be less important too. Although there may still be a use for weak fluid settling variations on the theme, not having to produce an Earth-like gravity field is a much easier engineering problem.
MiniMags produce an electric field around a spacecraft that interacts with the interplanetary plasma to produce a charge separation, strengthening the field. When ionizing radiation hits the electric field it is deflected and so does not cause damage to the spacecraft or its occupants. It was widely believed that such a "magnetic shield" of solar radiation could not be achieved without superconducting magnets and large power sources - placing it firmly in the domain of science fiction. However, a number of observations of solar wind phenomena and subsequent ground experimentation has shown that only a small electric field is initially needed - the neutral interplanetary plasma will do the rest.
Should MiniMags turn out to be effective at protecting spacecraft and human occupants from ionizing radiation they will solve perhaps the biggest problem with long term human exploration of space, and eventual colonization. Previously, the only known way to deal with the radiation problem was to surround the crew with mass. Over the years, a number of creative techniques have been devised to have the mass serve double duty - for example, using propellant or consumables mass to shield the crew. Careful study of the available materials for shielding has led us to determine that high hydrogen content materials like polyethylene are best, suggesting that the interior of crew cabins should be lined in the stuff, and windows should be replaced with periscopes (because ionizing radiation only travels in straight lines and is not reflected by mirrors). All these design problems go away with an effective radiation shield.
At the time of writing, neither of these technologies is being adequately funded. While the NASA Technology Roadmaps currently identify "pressure garment" suits as a potential avenue for research, they place it in the EVA-suit category and seem to be unaware of Skinsuits. MiniMags are not identified in the technology roadmaps at all.. This is particularly egregious as not only can MiniMags be used as a radiation shield, but they can also be used for in-space propulsion. As such, they should appear in both TA06 and TA02. But never fear! I've informed the Aeronautics And Space Engineering Board of this oversight and I'm sure they'll get right on it ;)
Thursday, January 20, 2011
"I was on the beach, at the water's edge and looked to the west to see a beautiful, bright moon. Except it wasn't the moon! It was a bright light moving slowly east, towards me and surrounded by a swirling mist. The mist rotated clockwise around the bright, white light and followed it perfectly."
Harry saw something strange in the sky, so he grabbed his video camera and put it up on youtube. It's a perfectly reasonable thing to do, and plenty of other people do the same. You could say it's a defining feature of the society we now live in. Most of us walk around with a camera in our pocket. Many of us whip out our camera phones to take a picture of anything interesting, funny, or even just to later post on Facebook to show that we're out having a fun time.
As it turns out, this particular UFO was quickly identified as the second stage of the first Falcon 9 flight, spinning uncontrolled despite valiant efforts by the thrusters to correct the spin. It was the only flaw of an otherwise perfect flight. The video was shot just 122km from me, but I wasn't looking at the sky that morning, I was asleep.
Despite the identification, the comment section of the video (truly the last refuge of intellectual thought) remains alive with speculation and denials. Included in the discussion is comparisons to the "Norway Spiral", another UFO sighting later identified as caused by a wayward rocket.
If you search youtube for UFOs you will discover a lot of videos which are legitimately people seeing stuff in the sky they don't understand. Almost all of them are comically identifiable: helicopters, aircraft, balloons, planets, and even the International Space Station - unfortunately searching for passes of the ISS doesn't get nearly as much. Many others are so mundane that one wonders why anyone would post them, or the UFO is only seen after the fact (a pretty big hint that you're seeing a video artifact). But there's certainly no shortage of video out there of UFOs.
Unfortunately, NASA gets harassed by the crazies and perhaps doesn't provide enough ridicule.. but, of course, ridicule is the CIA's job.
Friday, January 14, 2011
If you have one of these, turn it off now
It's almost funny whenever a member of Congress opens their mouth and says something about NASA. Thankfully I don't pull my hair out or I'd be bald by now, it's just that funny. Here's a quick list of things I have to remember to make sense of US space policy.
"Heavy Lift" means super heavy lift. Whenever a politician says "heavy lift", or just about anyone talking about space policy, they mean a vehicle that can lift more than 50 tons to LEO. Actually, they almost always mean a Saturn class vehicle.. and in many cases they actually just mean the Saturn V. When someone who actually works in the space industry says "heavy lift" they mean heavy lift - a vehicle that can lift more than 20 tons to LEO but less than 50 tons. And they almost always are talking about actual vehicles that you can place an order for right now.
The workforce is precious, and capable and vital, except for when they're aging. Unlike every other industry in the world where new people are being trained and old people are being retired, and people who get sick of their boss go find someplace else to work or even change to other careers, aerospace workers are fixed in number and hold their jobs for life. Yes, apparently the aerospace industry is a 50s utopia where Dad makes rockets and although he's highly trained and very very intelligent, if he were to be laid off he'd have no choice but to go on unemployment or, worse yet, take a job driving a taxi.
The space program is a matter of National Security. Except when it's not. NASA doesn't make missiles... or do they? Most everything "made by NASA" is actually made by the prime contractors like Lockheed Martin, Boeing, ATK, umm... Lockheed Martin - and these same companies also make fighter planes, bombs and, yes, missiles. A more cynical person than me would say that it seems NASA's primary purpose is to funnel money to these companies to support their infrastructure for making weapons. If you continue to scratch this one it'll never heal.
Kids love space and we can use that to trick them into studying science, technology, engineering and math (STEM). Obviously, kids are stupid and we need them to be smarter so we can keep the workforce vital because if we don't we'll lose the next war. That's right, the National Security of the USA depends on whether little Billy is inspired by NASA's Moon mission (or whatever they're doing this week) to become an astronaut when he grows up. We have to make it really hard to become an astronaut too - you need at least a PhD, but two would be better, and you have to join the Air Force.. preferably both at the same time - and everyone who drops out will get jobs on Lockheed Martin and make ICBMs. Yes, that's what I said - the aerospace industry is populated by failed astronauts, didn't you know?
SpaceX is the only commercial launch company in the world! Competition? What's that? The Soyuz is run by the Russian government who are still communists, no matter what they say. The Ariane is a myth invented by the French. Atlas and Delta are owned by the Air Force and only launch military satellites, they have no interest in this whole commercial thing. There's no market out there for commercial spaceflight anyway. It's not like anyone has a 24,000-sq-m assembly facility where they're assembling private space stations. They haven't already flown two prototypes on commercial rockets. Boeing hasn't signed any deals with them to deliver crew. Commercial - by which we mean SpaceX - isn't ready to fly humans, they haven't even demonstrated the launch of a capsule, orbit and successful return to Earth - something only 3 countries have ever done before.
Space Tourism is not real spaceflight. Oh, we're happy to support the burgeoning suborbital spaceflight industry. We voted for that law which said that if someone signs a contract promising they won't sue that they actually won't be able to sue you didn't we? Then we signed that other one that said their families won't be able to sue you. We sent our reps to your openings and got behind building lots of spaceports around the country. We got you those tax cuts didn't we? What, we didn't? Oh, ok, but we're trying, and that's what counts. We love suborbital space tourism because it doesn't interfere with our pork, but it's not real spaceflight.. I mean, it's not like anyone has ever flown to orbit and spent a week or two on the ISS. It's not like every seat that has ever been made available has been sold. Who would pay $20M to $40M and take time out of their busy lives to go to astronaut training, just for that. There's just no market, and anyway, there isn't any seats available. What's that? 2013 you say.
Did I miss any?