Customer Discussions > Science Fiction forum

Is NASA On Life Support?

Sort: Oldest first | Newest first
Showing 26-50 of 1000 posts in this discussion
In reply to an earlier post on Sep 21, 2009 2:30:33 PM PDT
Last edited by the author on Sep 23, 2009 10:13:01 AM PDT
To M. Helsdon:
RE: X-33 and VentureStar
Yeah, I remember both of those and the point is that they were cut --as you say, "mainly due to political will, or lack thereof." My point is that NASA has no intention of being a vanguard into space, and R&D resource, or anything else -- other than a jobs program for engineers and bureaucrats.

OK, so I'm more pessimistic than usual today.

In reply to an earlier post on Sep 21, 2009 2:53:46 PM PDT
Last edited by the author on Nov 5, 2009 9:31:04 AM PST
To Marilyn Martin:
It's extremely hard to predict political alignments twenty, thirty, or forty years into the future. However, it is certain (I think) that if humanity ever establishes a permanent presence in space, eventually there will be war. I wouldn't care to predict whether it would be on the moon or in the asteroid belt. It might not even be between governments, but rather between corporations. But, trust me on this, there will be war.

For a very good look at how near-future war in space might be fought, check out Ian Douglas' series The Heritage Trilogy. The books within the series are: Semper Mars, Luna Marine, and Europa Strike. Despite the hackneyed titles, those books provide a very good view of interplanetary warfare. There's a lot of gung-ho United States Marine Corps cheerleading (I don't mind), but the the science , in particular, is EXCELLENT.

To give you an example, here are a couple of excerpts. The first one is pretty straightforward -- a description of a Marine infantryman's rifle:
The M-29 ATAR, or advanced-technology assault rifle, was a direct-line descendent of the German-made G-11s of the last century, firing a 4.5mm ablative sabot caseless round with a muzzle velocity of over a kilometer and a half per second. With each bullet embedded in a solid rectangular block of propellant, there was no spent brass with each shot, and no open ejection port to foul with dirt, sand, or mud. The weapon was loaded by snapping a plastic box containing one hundred rounds into the loading port in the butt, a "bullpup" design that resulted in a rifle only seventy centimeters long and weighing just four kilos. The -29 looked like a blocky, squared-off plastic toy with a cheap telescope affixed to the top and a pistol grip on the bottom...which was why the men and women who carried them referred to the weapons as their toys.
The caseless ammo was both the M-29's greatest strength and its biggest weakness. The lack of shell casings to feed through an ejection port gave the rifle an incredibly high cyclic rate of twenty-five hundred rounds per minute, so fast that a three- or five-round burst could have the bullets on their way and dead on-target before the recoil had affected the shooter's aim. On the down-side, though, the firing chamber was easily fouled by chemical residues from the propellant blocks. The weapon used a clean-burning propellant, but there was always some gunk left over when it burned, and without an ejection port or shell casings, that gunk built up enough to degrade the rifle's performance after only a couple of mags.

Douglas, Ian. Semper Mars. New York, NY: HarperCollins, 1998, pp. 50-51.

The following excerpt describes the initial AI-directed bombardment of an enemy planet at .99c velocities:
Zero Hour...Zero Minute...Zero Second...
The leading cloud of sand had dispersed across a volume of space some fifteen thousand kilometers across, and each individual grain of sand, traveling at over ninety-nine percent of the speed of light, possessed incredible kinetic energy.
How much depended, of course, on the original mass of the grain. Sand particles range from 0.6 millimeter to about 2.1 millimeters in diameter. Quartz has a density of 2.67 grams per cubic centimeter, so the mass of a grain of sand ranges anywhere from three-tenths of a milligram to about 13 milligrams.
A particle massing 8 milligrams, however - fairly typical - released approximately 360 gigajoules - 360 billion joules of energy - when it hit something solid.
Three hundred and sixty thousand megajoules. That translated to about 72,000 kilograms of high explosive - seventy-two tons.
And there were 12,500 tons of the stuff in the first cloud.
William Blake had written of a world in a grain of sand; he hadn't intended that to mean a world of hurt....
And based on mass, a single metric ton of sand might contain something on the order of ten to the eleventh individual grains, and pack the equivalent of a 7.2 megaton nuclear explosion. Twelve and a half thousand tons of sand moving at near-c carried the destructive power of 90,000 megatons...though this first volley was dispersed over a very large area.
And nothing in that volume of space was safe from the incoming storm.

Douglas, Ian. Star Marines. New York, NY: HarperCollins, 2007, pp. 355-356.

In reply to an earlier post on Sep 21, 2009 6:38:32 PM PDT
Hey Marilyn-- re "how do you think governments will sort out the aspect of "ownership" (or "rent-to-buy") about the orbs in our solar system", you can look up the following 2 treaties on Wikipedia:

1) "The outer space treaty" - this went into effect back in 1967, and is signed by most counties. It disallows WMDs, and specifically "The effect of the Outer Space Treaty is to restrict control of private property rights, in the way that the law of the sea prevents anyone owning the high seas"
2) "The Moon Treaty" - Created in 1979 and has very few countries signed on. I remember getting mail from interest groups saying to write to my congressman to NOT support this, mainly for things in it like, "Bans all exploration and uses of celestial bodies without the approval or benefit of other states under the common heritage of mankind principle (article 11)." since this would put the brakes on almost any activity if you have to get other countries to agree each time on any activity. It was also real generic like "not contaminating" other bodies, so does landing a rover contaminate Mars? Hmmm.

Personally, I think if they DID open up SOME of the Moon and Mars to ownership, and said something like, oh, you can have 1/10th of the body you land on if you have a sustaining colony of xx people for a xx years, there would be a HUGE rush to be the first country to do this.

Posted on Sep 21, 2009 10:01:37 PM PDT
I think the problem is all political and financial, and right now, the financial picture isn't good with us just coming out of the worst recession since the Great Depression and up to our necks in national debt. There just isn't any money left for going to the Moon or Mars, or NASA itself.

But as a few other people have posted, the US isn't the only country that has a space program. When (and note that is "when" and not "if") China lands a man on the Moon, how will we feel about it? Will be content to be England after WW2 watching another country rise as we wane?

In more immediate terms, the shuttle was always an enormously expensive boondoggle that replaced the perfectly reliable Saturn rockets with a much more risky manned craft that really never justified the cost. For 90% of the payloads that the Shuttle took up, a reliable unmanned rocket would have been a better choice.

But we had to send astronauts up, or else we wouldn't have the photo-ops.

Unfortunately, those photo-ops included the destruction of a couple of those Shuttles, too.

Why on Earth would we want to build more shuttles? To give NASA more photo-ops? NASA should (and is) developing the next generation of solid-stage booster rockets to lift payloads into orbit. Quibbling about whether Lockheed-Martin or some other contractor really had a replacement for the shuttle is useless.

And as far as colonization: WHERE? The cost to get one man to Mars is estimated to be a trillion dollars, and you're not going to see any economy of scale by sending thousands. The "Europeans discovering America" cliche just totally falls apart on that point. Mars is inhospitable to life, and would take a massive sustained investment to keep even a handful of people alive.

Posted on Sep 22, 2009 6:18:58 AM PDT
Thanks one and all for the interesting and informative posts!

Bob, you hit on something I was thinking of. Perhaps we could have some kind of "homesteading" laws for our moon at least, which as you said, would give ownership of small tracts of the moon's surface to people who actually live and work there. (It would also prevent ownership-by-proxy, or money and contracts changing hands, and absolutely nothing's on that parcel of "land".)

Since science fiction, especially, loves playing with "What If?" situations, here's a scenario I've been pondering: What if the space agencies of Russia and China team up together permanently? (They are only talking joint missions now.) That would be a space-juggernaut that all other countries, even the U.S. with our unraveling NASA, couldn't stop.

And both Russia and China are heavily militarized, with the post-Communist mentality of "This is mine; that might be yours for now." Since the U.S. has the best or most advanced private space companies, could we protect them as they go about their for-profit business in space? What's to prevent a joint Russian/Chinese space presence from bullying our private space enterprises, or just taking what they want from these private asteroid miners, ect.?

I don't necessarily think war-in-space is inevitable. But I also don't think a paper-storm of treaties, directives and contracts will be worth anything in space, given this planet's weak-willed and uneven stabs at getting into space.

Your thoughts?

Posted on Sep 22, 2009 6:59:38 AM PDT
ttocsmij says:
NASA is just suffering from the cultural shift from "what can you do for your country" to "what can your country do for you". I'm sure JFK is mighty disappointed in how it is all turning out. We just spent trillions and billions on new bank accounts and new cars for the wealthy, not to mention the even larger expenditure being contemplated in the name of health "care" (whilst Congress keeps their luxurious plan intact of course). Just think what those funds could have done for bettering our lives through new technology developments (like feeding the planet properly and maintaining the biosphere we all share) not to mention vacationing on the moon (how cool would that be) and exploring the rest of the universe, eh! Sigh.

Posted on Sep 22, 2009 7:04:52 AM PDT
ttocsmij says:
P.S. I am somewhat amused that R.A.Lee thinks that signing treaties will keep weapons out of space. Would someone please nominate him for optimist of the year? Thanks.

In reply to an earlier post on Sep 22, 2009 7:36:15 AM PDT
Last edited by the author on Sep 22, 2009 7:37:32 AM PDT
Thanks for posting, ttocsmij!

The "we need to spend the money on Earth's ills" arguement has been around a long time, to try and explain how we don't need NASA or a Space Program. Which is just the "What can your country do for you?", self-centered mindset you quoted.

Any truly great civilization has to see and plan beyond the horizon. We should have multiple irons in the fire at all times, and be flexible enough to adjust when we need to. (Just look at all the sucess-stories of businesses who have weathered this recession, by being flexible enough to make serious "adjustments", and going in new and different directions, to stay afloat.)

Great Strides are being made to eradicate diseases and starvation on Earth. But we also need brave and visionary Great Strides toward a meaningful presence in space. Like I stated earlier, we may just desperately need those scientific discoveries and that outer space "presence" later on. (Besides someday having to find/build colonies to relieve over-population, maybe some of our most nutrious food products can grow at an accelerated pace in minimal/no gravity. Perhaps mining water from asteroids could add to Earth's already-taxed water supplies.)

Forget all the deadwood in Congress (I guess I'm the lone voice calling for Congressional Term Limits), who rant and grandstand over various governmental budgets, then shake-hands behind the scenes for substantial "bill-riders" to let them Bring Home The Pork.

Private Enterprise needs to step in forcefully to go -- and stay -- in space in a meaningful way. These private companies are focused and determined, and can get things done without massive amounts of sub-contractors, like NASA. (Which, at the end of the day, have had damn little to show.)

So, if everyone wants to gut NASA, why not throw some government money (a miniscule portion of NASA's yearly budget) behind some of those private space companies, thru grants or whatever, who are currently limping along in R&D-hell?

In reply to an earlier post on Sep 22, 2009 10:31:10 AM PDT
To Marilyn Martin:
RE: "Besides someday having to find/build colonies to relieve over-population..."

The world's population is increasing at a net rate of 75,000,000 people per year. There is no way, using current or foreseeable technology, that even 1% of that number can be transported off the planet, year after year.

RE: "Private Enterprise needs to step in forcefully to go -- and stay -- in space in a meaningful way. These private companies are focused and determined, and can get things done without massive amounts of sub-contractors, like NASA."

This is very true. The problem is with the extremely long lead times that will be necessary until there can be a significant return on investment (ROI). I would guess that there will have to be some combination of creative financing and bootstrap operations, where some activity with a short term ROI will help to fund an activity with a longer term ROI. I am NOT a financial officer nor an investment banker, so please excuse me if I don't have all the details exactly right.

In reply to an earlier post on Sep 22, 2009 10:54:25 AM PDT
M. Helsdon says:
"Perhaps we could have some kind of "homesteading" laws for our moon at least, which as you said, would give ownership of small tracts of the moon's surface to people who actually live and work there."

This is very remote: getting up to LEO is tricky; building a space station expensive; a lunar base very expensive. Until there are major advances in technology and huge investments, lunar homesteading is, unfortunately, fantasy.

"Since science fiction, especially, loves playing with "What If?" situations, here's a scenario I've been pondering: What if the space agencies of Russia and China team up together permanently? (They are only talking joint missions now.)"

Russia is actively involved in joint missions with NASA and ESA, so joint missions with CNSA isn't too surprising. And China has signed cooperation agreements with Brazil, Chile, France, Germany, India, Italy, Pakistan, Russia, Ukraine, the UK and the USA. It very unlikely, economically or politically, that Russia and China would unite with a common program.

"And both Russia and China are heavily militarized,"

Whilst the Chinese defense budget is subject to debate, the Russian Federation budget is roughly $39.6 billion, whilst the US budget is $636.39 billion.

About the only way of getting a foothold beyond LEO is by co-operation; only after lunar bases and asteroid mining becomes a reality is genuine space warfare likely. LEO space combat is, however, quite likely, as in a major conflict (or by a rogue state) knocking out the opposition's surveillance, communication and positioning satellites would be an immediate goal. In the 80s an F-15 fighter successfully shot down the P78 satellite and in 2007 China destroyed one of their own weather satellites in a kinetic weapon test. Existing treaties do not prevent conventional weapons being used in orbit.

Posted on Sep 22, 2009 11:23:45 AM PDT
Last edited by the author on Sep 22, 2009 11:27:15 AM PDT
Baby Steps:

All we need to do, at this point, is commit to going to Mars at some point. The problems start when we nail down deadlines and absolute milestones. Absolutes scare the financially inclined because they need a lot of money upfront.

I propose that we "sort of go". My idea is to ask for funding to set up for future missions.
In other words, we just want to ease in and send stuff ahead.

This would entail some relatively low (lower) cost milestones like putting fuel and water in orbit around Mars and continue to send exploratory robots but with a more scouting for manned landing site theme.

Provisions can take their time, people need to get there quick. Also, the provisions can be bundled in Earth orbit and then utilize less powerful (less expensive) rockets to send them into space.

By sending provisions ahead, on a slow boat, so to speak, we will be setting up for a safer mission and hedge up our chances for success. The financial risk will be leaving fuel and water in space should we need to cut funding - a relatively small loss. (which is only a loss if you are never going to use it)

The provisions could consist of, water, fuel, food, spare parts, emergency modules, etc. I'd really like to see provisions landed on the surface and some put in solar orbit with handy perigees that can be rendezvoused with easily.

(What I would really like to see is a provision station landed on Mars with a remote control car to go fetch the landing party if they land too far away. )

Anyway, that's my big idea for the day.


In reply to an earlier post on Sep 22, 2009 12:12:56 PM PDT
M. Helsdon says:

"My point is that NASA has no intention of being a vanguard into space, and R&D resource, or anything else -- or than a jobs program for engineers and bureaucrats."

I would contend that the majority of NASA scientists, researchers, engineers and technicians - and of course the astronaut corps, are all dedicated to being at the vanguard of space exploration, manned or unmanned. The politicians and bureaucrats... less so.

In reply to an earlier post on Sep 22, 2009 6:23:19 PM PDT
To M. Helsdon:
RE: "I would contend that the majority of NASA scientists, researchers, engineers and technicians - and of course the astronaut corps, are all dedicated to being at the vanguard of space exploration, manned or unmanned. The politicians and bureaucrats... less so."

I'm quite willing to admit that you're probably right. It's just quite a disappointment to see how far that NASA has deteriorated in the last 40 years. I suppose, however, that such a deterioration was inevitable, since the whole effort was essentially based on political paranoia.

RE: "...of space exploration, manned or unmanned."
To me, exploration means manned; investigation is unmanned. I think that this is more than merely a play on words.

Posted on Sep 23, 2009 8:33:14 AM PDT
Interesting, thought-provoking posts! Thank you one and all.

First of all, I was not criticizing NASA'S dedicated scientists, engineers and astronauts who are truly contributing, and are excited about space exploration. I was criticizing the too many sub-contractors who are only in it for the money, and may be muddying-the-water to keep that NASA money flowing.

Yes, Will, Baby Steps are needed. And I agree that "absolute timetables" are hard to nail down, when it comes to cutting-edge science and R&D. (Even tho' I'm still mystified why the shuttle fleet was to be retired by 2010, and all those NASA sub-contractors still couldn't come up with a replacement vehicle.)

Using unmanned craft to put "supply packages" on orbs and elsewhere in our solar system is a unique idea. (I'm not sure of the science here, but wouldn't those "supply packages" eventually deteriorate from particle bombardment we are protected from here on Earth under an atmosphere?)

Excellent point, Walter! "Exploration is manned; investigation is unmanned." And you're right, ROI (Return On Investment) is crucial to a permanent presence in space. Referencing a 3/15/07 TIME article on "Space Cowboys", Compusearch-founder Jim Benson, (who has developed a working-model of a "space taxi" that runs on rubber and laughing gas), is quoted as saying "If we want to go to space to stay, space has to pay."

Posted on Sep 23, 2009 10:42:10 AM PDT
To Marilyn Martin:
RE: "...Compusearch-founder Jim Benson, (who has developed a working-model of a "space taxi" that runs on rubber and laughing gas)..."

In response to your mentioning of Jim Benson and his space taxi, I've done a little research that I thought you'd be interested in seeing. The first item is about his forays into space entrepreneurship:

After a successful career as a computer industry entrepreneur, Benson decided to take on the challenge of starting a space commercialization venture. It combined his lifelong interests in science, technology and astronomy with his successful business experience.

Benson started the trend of successful high tech entrepreneurs moving into the space development arena, by incorporating SpaceDev, Inc. as a publicly owned space exploration and development company in 1997.

Benson and SpaceDev worked to develop the world's first private sector enterprise to profitably explore and develop space beyond earth orbit. SpaceDev's mission is to help "make space happen" for all of humanity, through the development of a comprehensive private space program, by delivering affordable and practical space technologies, products and solutions to SpaceDev's government and commercial customers, while creating value for SpaceDev stockholders.

SpaceDev acquired the former Integrated Space Systems, a space systems engineering firm, in 1998.

SpaceDev acquired the intellectual property of American Rocket Company in 1999 after AMROC's 1996 bankruptcy. The AMROC-derived hybrid rocket motors were used in several SpaceDev projects that followed.

SpaceDev started developing the science mission CHIPSat for the University of California, Berkeley in 1999. In 2003, SpaceDev launched the United States' smallest, low-cost, high performance satellite named CHIPSat for NASA. CHIPSat is a suitcase-size science microsatellite that is also the first U.S. mission to use only TCP/IP Internet communications for end-to-end satellite operations control, becoming the first satellite whose mission control and operations center is any laptop computer located anywhere in the world. Although the nominal mission duration was one year, the satellite operated successfully for almost five years when mission was terminated in April 2008.

In 2004, SpaceDev's hybrid rocket motors were used by Burt Rutan's SpaceShipOne to win the $10 million Ansari X Prize.

During his 10 years with the company, Benson served as founder, chairman, chief executive officer and chief technology officer of SpaceDev. He stepped down on September 28, 2006 to announce that he was starting a new venture called Benson Space Company.

Benson Space Company
Jim Benson announced on September 28, 2006 that he had launched an ambitious new venture focused on commercial space tourism, Benson Space Company.

Benson Space intends to be first to market in the emerging multi-billion dollar space tourism or personal spaceflight industry, with the safest and lowest cost astronaut-making suborbital missions.

"I am dedicated to opening space for all of humanity and, with SpaceDev well-managed and growing, I plan to spend the next several years creating the possibility that anyone who wants to go to space will be able to, safely and affordably," said Benson. SpaceDev owns many of the patents and intellectual property rights associated with hybrid rocket motors used for safe human spaceflight. Under Benson's guidance, SpaceDev developed critical hybrid rocket motor technology and furnished all of the rocket motors for Paul Allen's SpaceShipOne, the craft that earned the $10 million Ansari X Prize in 2004.

Benson Space has completed its first round of financing and submitted a request for proposal to SpaceDev for the design and development of its SpaceDev Dream Chaser spaceships. BSC expects to be one of SpaceDev's largest customers, purchasing multiple spaceships and safe hybrid rocket motors for use in personal spaceflight.


The next item is about the hybrid rocket, the engine of the space taxi you mentioned:

Hybrid Rocket
A hybrid rocket is a rocket with a rocket engine which uses propellants in two different states of matter - one solid and the other either gas or liquid. The Hybrid rocket concept can be traced back at least 75 years.

Hybrid rockets exhibit advantages over both liquid rockets and solid rockets especially in terms of simplicity, safety, and cost. Because it is nearly impossible for the fuel and oxidizer to be mixed intimately (being different states of matter), hybrid rockets tend to fail more benignly than liquids or solids. Like liquid rockets and unlike solid rockets they can be shutdown easily and are simply throttle-able. The theoretical specific impulse(Isp) performance of hybrids is generally higher than solids and roughly equivalent to hydrocarbon-based liquids. Isp's as high as 400s have been measured in hybrid rockets using metalized fuels. Hybrid systems are slightly more complex than solids, but the significant hazards of manufacturing, shipping and handling solids offset the system simplicity advantages.

Basic Concepts
In its simplest form a hybrid rocket consists of a pressure vessel (tank) containing the liquid propellant, the combustion chamber containing the solid propellant, and a valve isolating the two. When thrust is desired, a suitable ignition source is introduced in the combustion chamber and the valve is opened. The liquid propellant (or gas) flows into the combustion chamber where it is vaporized and then reacted with the solid propellant. Combustion occurs in a boundary layer diffusion flame adjacent to the surface of the solid propellant.

Generally the liquid propellant is the oxidizer and the solid propellant is the fuel because solid oxidizers are problematic and lower performing than liquid oxidizers. Furthermore, using a solid fuel such as HTPB or paraffin allows for the incorporation of high-energy fuel additives such as aluminum, lithium, or metal hydrides.

Common oxidizers include gaseous or liquid oxygen or nitrous oxide. Common fuels include polymers such as polyethylene, cross-linked rubber such as HTPB or liquefying fuels such as paraffin.

Advantages of Hybrid Rockets
Hybrid rocket engines exhibit some obvious as well as some subtle advantages over liquid-fuel rockets and solid rockets. A brief summary of some of these is given below:

Advantages compared with bipropellant liquid rockets
1. Mechanically simpler - requires only a single liquid propellant resulting in less plumbing, fewer valves, and simpler operations.
2. Denser Fuels - fuels in the solid phase generally have higher density than those in the liquid phase
3. Metal Additives - High energy metals such as aluminum, magnesium, lithium or beryllium can be easily included in the fuel grain increasing specific impulse(Isp)

Advantages compared with solid rockets
1. Higher theoretical Isp obtainable
2. Less explosion hazard - Propellant grain more tolerant of processing errors such as cracks
3. More controllable - Start/stop/restart and throttling are all achievable with appropriate oxidizer control
4. Safe and non-toxic oxidizers such as liquid oxygen and nitrous oxide can be used

Disadvantages of Hybrid Rockets
Hybrid rockets also exhibit some disadvantages when compared with liquid and solid rockets. These include:

1. Oxidizer-to-fuel ratio shift ("O/F shift") - with a constant oxidizer flow-rate, the ratio of fuel production rate to oxidizer flow rate will change as a grain regresses. This leads to off-peak operation from a chemical performance point of view.
2. Low regression-rate (rate at which the solid phase recedes) fuels often drive multi-port fuel grains. Multi-port fuel grains have poor volumetric efficiency and, often, structural deficiencies. High regression-rate liquefying fuels developed in the late 1990s offer a potential solution to this problem.
For a well-designed hybrid, O/F shift has a very small impact on performance because Isp is insensitive to O/F near the peak.

In general, much less development work has been performed with hybrids than liquids or solids and it is likely that some of these disadvantages could be rectified through further investment in research and development.

Hybrid Safety
Generally, well designed and carefully constructed hybrids are very safe. The primary hazards associated with hybrids are:

1. Pressure vessel failures - Chamber insulation failure may allow hot combustion gases near the chamber walls leading to a "burn-through" in which the vessel ruptures.
2. Blow back - For oxidizers that decompose exothermically such as nitrous oxide or hydrogen peroxide, flame or hot gasses from the combustion chamber can propagate back through the injector, igniting the oxidizer and leading to a tank explosion. Blow-back requires gases to flow back through the injector due to insufficient pressure drop which can occur during periods of unstable combustion. Blow back is inherent to specific oxidizers and is not possible with oxidizers such as oxygen or nitrogen tetroxide unless fuel is present in the oxidizer tank.
3. Hard starts - An excess of oxidizer in the combustion chamber prior to ignition, particularly for monopropellants such as nitrous oxide, can result in a temporary over-pressure or "spike" at ignition.
Because the fuel in a hybrid does not contain an oxidizer, it will not combust explosively on its own. For this reason, hybrids are classified as having no TNT equivalent explosive power. In contrast, solid rockets often have TNT equivalencies similar in magnitude to the mass of the propellant grain. Liquids typically have TNT equivalencies calculated based on the amount of fuel and oxidizer which could realistically intimately combine before igniting explosively; this is often taken to be 10-20% of the total propellant mass. For hybrids, even filling the combustion chamber with oxidiser prior to ignition will not generally create an explosive with the solid fuel, the explosive equivalence is often quoted as 0%.


Posted on Sep 23, 2009 12:05:02 PM PDT
Last edited by the author on Sep 24, 2009 7:02:28 AM PDT
To Marilyn Martin:
When you mentioned a space taxi, I didn't realize that you were referring to Burt Rutan's and Paul Allen's SpaceShipOne. Below is an excerpt from an article on the spacecraft.

Scaled Composites SpaceShipOne
SpaceShipOne is a rocket-powered aircraft that completed the first privately funded human spaceflight on June 21, 2004. It was developed by Scaled Composites.

SpaceShipOne was developed by Mojave Aerospace Ventures (A joint venture between Paul Allen and Scaled Composites, Burt Rutan's aviation company, in their Tier One program), without government funding. On June 21, 2004, it made the first privately funded human spaceflight, and on October 4, it won the $10 million Ansari X PRIZE, by reaching 100 kilometers in altitude twice in a two-week period with the equivalent of three people on board, with no more than ten percent of the non-fuel weight of the spacecraft replaced between flights. Development costs were estimated to be $25 million, funded completely by Paul Allen.

During its testing regimen, SpaceShipOne set a number of important "firsts", including first privately funded aircraft to exceed Mach 2 and Mach 3, first privately funded manned spacecraft to exceed 100km altitude, and first privately funded reusable manned spacecraft.

SpaceShipOne is an experimental air-launched rocket-powered aircraft with suborbital flight capability that uses a hybrid rocket motor. The design features a unique "feathering" atmospheric reentry system where the rear half of the wing and the twin tail booms folded upward along a hinge running the length of the wing; this increased drag while remaining stable. The achievements of SpaceShipOne are more comparable to the X-15 than orbiting spacecraft like the Space Shuttle. Accelerating a spacecraft to orbital speed requires more than 60 times as much energy as lifting it to 100 km.

SpaceShipOne is registered with the FAA as N328KF. N is the prefix for US-registered aircraft; 328KF was chosen by Scaled Composites to stand for 328 kilo feet (about 100 kilometers), the officially designated edge of space. The original choice of registry number, N100KM, was already taken. N328KF is registered as a glider, reflecting the fact that most of its independent flight is unpowered.

SpaceShipOne's first flight, 01C, was an unmanned captive carry flight test on May 20, 2003. Glide tests followed, starting with flight 03G on August 7, 2003. Its first powered flight, flight 11P, was made on December 17, 2003, the 100th anniversary of the first powered flight.

On April 1, 2004, Scaled Composites received the first license for sub-orbital rocket flights to be issued by the US Office of Commercial Space Transportation. This license permitted the company to conduct powered test flights over the course of one year. On June 17, 2004, Mojave Airport reclassified itself (part-time) as the Mojave Spaceport.

Flight 15P on June 21, 2004, was SpaceShipOne's first spaceflight, and the first privately funded human spaceflight. Ansari X PRIZE flights followed, with flight 17P on October 4, 2004, winning the prize.

The SpaceShipOne Team was awarded the Space Achievement Award by the Space Foundation in 2005.

General characteristics
Crew: one, pilot
Capacity: 2 passengers
Length: 16 ft 5 in (5 m)
Wingspan: 16 ft 5 in (5 m)
Height: ()
Wing area: 161.4 ft² (15 m²)
Empty weight: 2,640 lb (1,200 kg)
Loaded weight: 7,920 lb (3,600 kg)
Powerplant: 1× N2O/HTPB SpaceDev Hybrid rocket motor, 7,500 kgf (74 kN)
Isp: 250 s (2450 Ns/kg)
Burn time: 87 seconds
Aspect ratio: 1.6

Maximum speed: Mach 3.09 (2,170 mph, 3,518 km/h)
Range: 35 nm (40 mi, 65 km)
Service ceiling: 367,360 ft (112,000 m)
Rate of climb: 82,000 ft/min (416.6 m/s)
Wing loading: 49.07 lb/ft² (240 kg/m²)
Thrust/weight ratio: 2.08


Posted on Sep 24, 2009 12:40:39 AM PDT
there are no political reasons to have a space program right now.... when a politician wants to manipulate the American people, you'll hear something about the space program again.....

THERE IS NO ACTIVE space program!! The people who run this country don't want it right now, and neither does the government.....

In reply to an earlier post on Sep 24, 2009 7:40:33 AM PDT
THANK YOU, Walter! I enjoyed reading about those private space companies, and the geniuses behind their spacecraft.

I wasn't aware Jim Benson had left SpaceDev to form another company, Benson Space Company. Although I'm unclear about exactly what BSC is doing, since they intend to buy all their hardware from SpaceDev. (Personally I can't wait to ride that space taxi fueled by rubber and laughing gas. Passengers getting too scared? Just a teeny tiny fuel leak should do the job ...)

In reply to an earlier post on Sep 24, 2009 10:01:32 AM PDT
You're most welcome, Marilyn!
RE: "Personally I can't wait to ride that space taxi fueled by rubber and laughing gas."

Well, all you have to do is go to Virgin Galactic at the following website:, and sign up! Of course, you might have to wait a few years before your flight is scheduled...

Posted on Sep 26, 2009 7:28:46 AM PDT
Galgar says:
I agree with the poster above who attributed NASA's rather sad state to changes in our culture. I remember going to a lecture by a former NASA engineer who had worked on Apollo, and being amazed at the risks that we were willing to take to get men to the moon and back. Then he mentioned that before you can launch a space shuttle, you have to clear several million safety checks. Part of this is that they designed the space shuttle to do everything (and therefore made it amazingly complex), and part of this is that we have become a risk-averse culture. I remember the hand-wringing that followed the Challenger explosion, how everyone was worried that our children would be permanently scarred by the event, etc. Well, the fact is that life is risky, and if you want to achieve anything, you have to take some risks. We have, quite simply, lost our willingness to take even prudent risks in exchange for big payoffs.

I think another problem has been the way that we can now create missions to the moon, Mars, and anywhere else without leaving home. There is software available for the home computer that can make pictures of spaceships, other planets, etc., without having to take the risk or spend the money to actually go into outer space. We can pretend we're exploring rather than actually exploring, and so we can write the exciting stories we want, rather than risk finding out that the Martians (or whatever aliens) aren't real after all.

Posted on Sep 26, 2009 5:22:22 PM PDT
J. Huck says:
Put what several billion there are into the space elevator and make the cost of lifting mute. Anything on the table now is about 'more business of similar nature' to aerospace/rocket building entities. Tech change is upon US and all these rocket proposals for crew/supply to LEO should go private but NASA should not throw an anchor into the past with this ORION stuff and we/others should knock out the cost of getting off the ground.

Posted on Sep 26, 2009 6:52:44 PM PDT
Thanks for your interesting, thoughtful posts, J. Huck and Galgar.

The space elevator is a favorite of some posters here. But the current barrier is that no one has yet discovered a "tether" that can do the job.

You may want to check out another discussion in this forum, "Race to Space ..." that discusses how private enterprise is set to eclipse NASA and get into space to stay. They don't have the major bucks NASA does/did, but they have the determination and smarts to get into space meaningfully, and at a fraction of the cost.

In reply to an earlier post on Sep 26, 2009 7:10:18 PM PDT
To Marilyn Martin:
Here's a link to a website that's about the space elevator: Also there's an excellent book, The Space Elevator: A Revolutionary Earth-to-Space Transportation System, by Bradley C. Edwards and Eric A. Westling. It's available on and is well worth it.

In reply to an earlier post on Sep 26, 2009 7:17:17 PM PDT
Last edited by the author on Nov 5, 2009 9:41:16 AM PST
To Marilyn Martin:
Carbon nanotubes (a.k.a. buckytubes) seem to be the best current candidate for a space elevator tether material. Admittedly, much more reseach and development needs to be done, but it is getting done. Here's a link to one website:

Posted on Sep 27, 2009 2:23:23 PM PDT
Last edited by the author on Sep 27, 2009 2:26:49 PM PDT
To anyone still following this discussion, had a 9/25/09 article (in Science) titled : "Russia Hopes U.S. to Extend Shuttle Operations".

According to the Russian space agency's (Roscosmos) chief, Anatoly Perminov, they would like NASA to extend the use of their shuttles beyond 2011. "Then the situation would change substantially and it would be possible to work jointly with the Americans. Unlike now, when the main burden (for the ISS) lies with the Russian side."

Mr. Perminov has had no official reaction. But says that unofficial communications indicate that the extension of the shuttles' usage is possible.

Thanks for the links, Walter. There are million-dollar contests right now, trying to get someone to come up with a workable "tether".
[Add comment]
Add your own message to the discussion
To insert a product link use the format: [[ASIN:ASIN product-title]] (What's this?)
Prompts for sign-in


This discussion

Discussion in:  Science Fiction forum
Participants:  99
Total posts:  1309
Initial post:  Sep 19, 2009
Latest post:  Sep 15, 2013

New! Receive e-mail when new posts are made.
Tracked by 6 customers

Search Customer Discussions