From its founding in 1917 until the beginning of the space race, every NACA project was intended to be of practical value. Goals flowed up from the engineers and in from industry. This era is well documented in James Hansen's book "Engineer in Charge". After Sputnik the situation changed radically; the space race was not a scientific quest, it was a substitute for a perilous nuclear arms race. The Apollo program was canceled simply because it achieved its goal, and continuing to fly people to the moon with expendable rockets was much too expensive. The Shuttle was our first attempt to provide human spaceflight at a practical cost. It failed to achieve this goal because decisions were made on critical systems, such as the SRBs and heat shielding, without any prototypes to test them in actual flight. This resulted in highly inaccurate assessments of both maintenance cost and safety. But concluding on the basis of this one program that reusable spacecraft are impractical is like flying only the Wright Flyer until 1930 and then concluding that heavier-than-air flight is impractical and going back to balloons.

Just ten years ago NASA was well aware of this, and was developing a new series of unmanned "X- planes" that would provide flight experience on reusable spacecraft technologies, and thus enable a future generation of reusable spacecraft that would be both safe and practical. The X-33 was canceled because it was concluded that a composite LH2 tank was impractical, although the DC-X was already flying with just such a tank. The DC-X prototype was destroyed because the program was understaffed, leading to a maintenance error. The X-34 was canceled without explanation. When the airframe contractor offered to fly the X-34s at its own expense NASA inexplicably refused, even though sharing of public and private investment had been one of the goals of the program. The X-37 was transferred to DOD, but since DOD has no human spaceflight mission it is difficult to see how it can ever be used for its original purpose.

The fundamental deficiency of the Constellation program is the lack of a credible strategic goal that justifies its cost. Another race to the moon with China, a country as capitalist as the US and our major trading partner, would leave us further in debt and would serve no purpose for either country. Helium-3 has been proposed as a lunar resource so valuable it could be shipped back to earth at a profit, but the proton + boron-11 reaction has all the advantages of helium-3 fusion and the reactants are readily available on earth. Research and tourism in space are reasonable goals but are highly sensitive to cost. Constellation, like Apollo, is unaffordable for these purposes. At over $1B for a lunar flight; it would be analogous to maintaining a permanent base at the South Pole using only dogsleds. Fully reusable launch vehicles and spacecraft remain the only prospect for practical human spaceflight, but because of the cost of the program, no resources will be available to develop such advanced technology.

The cost of human spaceflight is often justified to the public by the practical benefits of NASA-funded research, particularly through advances in medicine. Ostensibly these are free "spinoffs"of spaceflight that cost nothing in themselves. But in reality such cases are rare. There are a wealth of ideas but little institutional support for work that is not considered essential to the primary mission of returning Americans to the moon, even for research that could save many lives here on earth.

The space program continues to attract brilliant scientists, engineers, and students who can make air travel safer and less expensive, develop hydrogen-fueled airliners, protect the environment, improve communications and navigation, help US companies recapture a share of the commercial launch market, and make important advances in medical and life sciences. But to do these things NASA must once again produce science and technology of practical value to America, not as an accidental byproduct, but as its primary goal. It is time for the agency to return to its original mission, not the mission that was forgotten when the moon race ended, but rather the mission that was forgotten when the moon race began.

2006-08-04

I have noticed that sometimes NASA makes a series of judgments, each of which appears logical, only to reach a conclusion that simply does not seem right. The current plan for manned spaceflight with the shuttle-derived CLV is such a case.

I've had the chance to tour the Delta IV pad several times, and the Shuttle facilities for many years. The difference in complexity of operations is dramatic. The Shuttle SRBs require tedious and hazardous crane operations to stack the segments. The Mobile Launcher Platform is built like a ship and the crawler is immense. The Delta IV has no mobile pad. It is integrated horizontally in a building that doesn't even have a crane, and despite its size the "heavy" is actually so light unfueled that it can be carried to the pad on a rubber-tired transporter. Like the Soyuz, the Delta is rotated to vertical at the pad by an erector arm; faster and probably less hazardous than crane rotation. In the long run the cost of operations is proportional to the number of people and hours it takes to do the job, and the Delta IV is assembled and launched at Cape Canaveral by a total workforce of less than 300.

The LSAS maintained that an entirely new pad costing billions would be needed if an EELV were used for manned launch. But the only specific reason I have actually heard was that "we do not think the EELV programs want us interfering with their operations". I am not sure the EELV programs actually said this, since they are operating well below capacity and are being forced to merge, so would hardly object to a new customer. There were general statements suggesting major modifications were needed to "man-rate" the pad, but in fact CX-37 has a massive umbilical tower that already has three swingarms; adding a fourth for crew access would be a fairly minor modification.

The LSAS cost estimate for Delta IV launch of the CEV was also increased by requiring a redesigned second stage to meet a design load factor of 1.4 (used for Shuttle) vs the current 1.25 DoD spec. But the design load factor is simply a way of reducing the risk of structural failure when the actual loads aren't precisely known, or when the structure may be weakened by fatigue. The appropriate load factor is a function of the how well the load can be predicted. The Shuttle was a radical design that had to fly with a crew the very first time, and it was to be capable of 100 flights with the attendant fatigue and vibration. The Delta IV upper stage load structure is a simple cylindrical truss that is only used once, and could easily be flown unmanned with a test load and strain gauges to verify the actual flight loads. The design load factor for the 40-year-old Apollo Lunar Module, which had to fly manned the first time it landed, ranged from 1.35 for nominal loads to 1.0 for loads considered possible but unlikely. The LSAS also stated that extensive modifications would be needed to give the crew "control of the stack". Just what control do they have with a solid fueled rocket in the CLV? There's not even a throttle. Everyone still breaths a sigh of relief when the Shuttle SRBs separate.

Estimating total costs early in the design phase is not an exact science; there has never been a rocket that didn't cost more in hardware than it did on paper. The Delta IV is operational so its cost estimates are considerably more reliable than those for the CLV, and even after these added costs the LSAS concluded that the cost of the Delta IV would still be no more than the SRB-derived CLV. But it was rejected anyway because, even though the single-core version was safe enough, the heavy version was said to be to dangerous because it would have three identical stages, and thus (presumably) three times the failure rate. This was a simplistic and inappropriate reliability analysis since virtually all launch failures are due to design flaws or procedural errors, not random processes such as wearing out of parts. Three identical core stages thus have essentially the same failure rate as one. Solids also have rapid failure modes that may not provide time for crew escape, and can.t be test-fired before use; conversely, no credit at all was provided for the fact that the Delta IV Heavy can shut down in the event of a contingency requiring crew escape at significant speed, just as the Saturn was designed to do, or the reduced cost of conducting launch preps on a non-hazardous vehicle, or the ability to test future modifications of the vehicle in flight on launches that do not carry the CEV.

Of course one can arbitrarily pick a specification that will force the choice, such as payload mass. But given the early stage of CEV design, it is hard to see why CEV flights to the Space Station could not be launched well within the 23MT LEO capacity of the Delta IV Heavy "as is", with very limited modifications. If 30MT were really needed for a lunar flight, four one-piece Delta SRBs ($1M each) could be added.

We cannot conquer space if we cannot make unbiased choices. The LSAS has a number of questionable assertions, all of which seem to bias the CLV selection toward the shuttle-derived design. The Delta IV Heavy is elegantly designed in both vehicle and processing, is intrinsically efficient and reliable, and it is already operational. To suggest that it will be cheaper or safer to design, build, and most important, operate a new rocket with 70's technology and solid fuel when we already have a modern liquid-fueled rocket that can do the job simply flies in the face of common sense. 2006-01-06

X-33 Calcellation

It was widely reported that the X-33 was cancelled because of delamination of its lightweight composit liquid hyudrogen tank. After the program cancellation one of the contractors actually completed and tested a composite LH2 tank sucessfully. The problem was that air betwen the laminations was freezing, drawing in more air which froze. On warming up the air expanded and forced the laminations apart. After the program cancellation the contractors actually completed and tested a composite LH2 tank sucessfully through many cycles, using the close-out funds. The problem was cryopumping; air betwen the laminations was freezing, drawing in more air which froze. On warming up the air expanded and forced the laminations apart. The solution was to seal the surface with metal foil. The whole story on this is in AvWeek. Unfortunately by then the program had been cancelled. The people who said it couldn't be done were simply wrong, and didn't understand technology development.

NASA was unrealistic in requiring the contractor to pay a large part of the development cost for what was a suborbital technology demonstrator, not a vehicle that could actually make money. The reason NASA exists is to fund high-risk development that private industry cannot afford. Obviously even the VentureStar could not fly into orbit. It was just a design concept. The mass fractions were literally pulled out of the air. But if Lockheed hadn't said it could, they wouldn't have gotten the contract for the X-33.

But if the X-33 and other suborbital technology demonstrators had been allowed to fly, what we could have learned might have made practical human spaceflight possible.

The info on the DCX sounds right on target. Obviously the program was inadequately funded, then cancelled when it hit a minor snag. Then all the other technology demonstrators were cancelled to pay for a $4 Billion overrun in the outyears of the ISS program. Then the ISS and Shuttle programs were truncated to pay for a fantastically expensive return the the Moon with ELVs and 30-year-old technology.

Bottom line: we need to decide whether NASA's primary mission is to fly, or to advance the technology of flight.

One of the theories advanced here is that contact between advanced and primitive civilizations can undermine the less advanced culture. However on Earth that's never been a deterrent to the more advanced culture making contact, nor, in most cases, has the more advanced culture suffered.

With regard to range, the critical parameters are frequency, transmitter power, gain at each end, receiver sensitivity, and integration time. Shuch http://www.setileague.org/articles/oseti.htm gives a quite conservative assessment of Arecibo that limits it at current capabilities to 10,000 lightyears at 1420MHz, about one eighth of the galactic diameter, somewhat less than Drake's estimate of half the galactic diameter but certainly enough to search a significant fraction of the galaxy. A proposed system called Cyclops would have had a range of several times the galactic diameter, using more antennas but current amplifier technology.

Star Wars notwithstanding, it's difficult to identify any credible rational for an interstellar invasion. The energy and technology required for such an undertaking could provide much greater material rewards through terraforming or space colonization near to home. Remember that if there were bars of solid gold on the moon, it would not be worth the cost to return them to Earth.

So the most likely explanation for the absence of aliens is simply that civilization is rare and that we may be the first to achieve technology. Although there is some possibility of habitable planets around dwarf stars, (see http://www.universetoday.com/am/publish/seti_sets_site_on_mdwarfs.html so far as is known any star significantly larger or smaller than the sun will not do, nor will a planet significantly larger or smaller than Earth, or any location much closer or farther from the galactic center. Even here we barely made it; in a mere 100 million years Earth will be unliveable.

If other civilizations exist, they are unlikely to be any threat. If they had the technology to get here physically, they would already have done so. All sides benefit from an exchange of knowledge. We have nothing to fear from setting a beacon, and potentially much to gain.

The SETI paradox states that if all civilizations act the same, and we listen but do not transmit, then most likely everybody is listening and no one is transmitting, so there will never be communication.

However I think the lack of METI in the past was partly due to the assumption that since we had just developed the technology, the other communicating civilization would probably be more advanced and thus be able to transmit at a power not available to us, and do it continuously. In addition there was the impatience factor. If civilizations were common, signals could be received immediately but it would take many years to get a reply to a transmission even if it was heard immediately. I don't think there was any specific reluctance to transmit, at least I did not hear it from Drake or others at a conference I attended in 1985.

Now that the technology is available with planetary radar transmitters, and the prospects of detecting another civilization by incidental signals appears dim, there's nothing to prevent us transmitting to the extent that we can, and I think we should start. Surely that would answer the SETI paradox, since the assumption of mediocrity would suggest other civilizations would do the same.

However I think the prospect of communicating with other technological civilizations appears less likely than it once did, given that the transition from unicellular to multicellular life required more than half the total tme the Earth will be habitable, the discovery that the majority of extrasolar planets so far detected are in relatively unstable systems, the Fermi paradox,and the difficulty in communicating even with other intelligent species on earth.

The Global Flyer is in the only actual hangar on KSC property, commonly called the X-34 Hangar. It was built with funding from the State of Florida in an attempt to attract some flights of the X-34 program to KSC. Of course, the X-34 was canacelled so the hangar was rented to United Space Alliance to store GSE. Later it was used for the Columbia debris investigation. It is a fabric-roofed structure.

Steve Fosset gave a talk for the employees. He has quite a number of records. The Flyer is pressurized, but cruises at about 45,000 feet. I should mention that I have been to 43,000 in an altitude chamber, and tried pressure breathing. It's not easy, even on pure oxygen! If the engine fails, pressure will leak down in a few minutes. He has a 10-minute oxygen suppply, but on the first round-the-world flight he accidentally tripped the oxygen supply while getting into the cockpit, but decided to continue anyway even though the loss of the engine might have been fatal. He also had a failure of the GPS when crossing the border into Canada and lost about 1500 lbs of fuel because the fuel vents did not function properly when the wings flexed upward dramatically in flight; apparently they had not done any test flights with full fuel.

All in all, he is a person of remarkable determination and daring, however he took some risks that most pilots would not have considered prudent.

It is great to finally have a 21st century aircraft at KSC. Fosset said that perhaps NASA should help make carbon-fiber technology more available in aircraft of all types.

[9/7/09] Fosset, of course, later died in the crash of a small aircraft, as did Scott Crossfield, first pilot of the X-15. Irony, but still both died doing what they loved.

vulture@vulturesquadron.com