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Interesting Article - I'm not really sure what Mr. Walker's agenda is beyond nuclear powered rockets and why Prince posted it here - but I do agree with the articles conclusion:
Thirty-three years after Armstrong is long enough. It is time for private companies to go into space and mine it, settle it, tame the Earth-crossing asteroids, and generally do some serious rocket science. It is time to travel to the asteroids before another asteroid travels here.
Order of Kilopi
Progress is a recent idea in human thought. The concept of progress gained momentum at the 19th century, with Auguste Comte. It's just an illusion.
Surely we need a break through in space locomotion. Chemical rockets have reached their limit. We're not going anywhere with them.
<a name="20020716.5:13"> page 20020716.5:13 aka Rocket man in Math Hour
Way back? in the era of 3D movies {those were neat}
my favorite ongoing serial, {kept me seated}[Sat Matane']
was Rocket Many? That was scores of year's
before the actuall "BACK PACK"'s of individual
transport were a reality: aLass even back then
as a sall child i could see the reality of
the concept Keep you Super Man, Bat Man, & Robin
orWonder Woman. Nope for me it was Rocket man that
I wanted to see: So sure it makes me Sad that there are no longer 3D movies! Sigh..hh oh Uh.hU,
Member
I think a HTHL craft is best for any manned flights and should be the consideration for alkl future NASA and private designs where-ever possible, not only do you benifit from the lift generated by wings but conventional jet fuels may be used in the first stage and after a possible refuleing, one could then use the second stage to reach your desired altitude above the earths surface, using the first stage to reach any desired maximum altitude. The first stage would than detatch and orbiter and fly back to a conventional runway. Andrews Aerospace is working on a similar system as well as Northrop Grummen for the space launch initiative.The whole private space effort (unmanned at least) is about to get much more accessable and cheaper thanks to the develpment on both sides of the pond of new, cheaper rockets to carry payloads of greater mass, or simply cheaper into space.
The new Delta 4's will be the first new rocket engine constructed from scratch in the US in 30 years and it appears that bussiness at least in unmanned sattalite and commercial applications involving dedicated space systems is about to boom. If only this were to occur to manned space flight like sattalites, we would have a steady foothold in space beyond the scope of the ISS and temporarily grounded shuttle programs. The Ariane has been launching commercial payloads for 5 years without significant problems and these other designs are intended to be even more effective, the Delta 4 being the one that has not yet been deployed yet and will be sometime this month. The atlas and the Ariane that I know have the option of a heavy lift capacity in which they could place a larger payload into orbit with extra strap on SRB boosters.
Vehicle: Ariane 5
Maker: Arianespace (France)
First launch: June 1996
First payload: Cluster scientific satellites (destroyed)
Capacity (in Chevy Suburbans): 3.8
More info: http://www.arianespace.com
Vehicle: Delta 4
Maker: Boeing (U.S.)
First launch: July 2002
First payload: Eutelsat telecommunications satellite
Capacity (in Chevy Suburbans): 5.0
More info: http://www.boeing.com
Vehicle: Atlas 5
Maker: Lockheed Martin (U.S.)
First launch: May 2002
First payload: Hot Bird 6 TV broadcasting satellite
Capacity (in Chevy Suburbans): 3.1
More info: http://www.lockheedmartin.com
Vehicle: Proton M
Maker: Khrunichev (Russia)
First launch: April 2001
First payload: Ekran M communications satellite
Capacity (in Chevy Suburbans): 2.1
More info: http://www.khrunichev.ru
Source for the above: www.popularscience.com
-Mark.
Order of Kilopi
Question:
What is "a HTHL craft"?
Order of Kilopi
Horizontal Take-off and Landing (???). This man knows. It seems to be a thing that Russians like.On 2002-07-17 15:02, Kaptain K wrote:
Question:
What is "a HTHL craft"?
Just in case of trouble with acronyms:
http://www.faqs.org/faqs/space/acronyms/
<font size=-1>[ This Message was edited by: Argos on 2002-07-17 17:15 ]</font>
Order of Kilopi
Thanks Argos.
I have been advocating this (with a catapult first stage and winged scram-jet second stage) since the old board.
Why is NASA so intent on doing it the hard way when SF writers figured this out 60 years ago? [img]/phpBB/images/smiles/icon_confused.gif[/img]
Order of Kilopi
Yeah. I saw movie in my childhood (I forgot the name), about a forced population withdrawal from Earth in account of the expansion of the Sun (Noah's ark fashion). Only the best young people of the planet embarked in a cigar-shaped spaceship (a classic design of the 30's and 40's) which was catapulted in a long rail. That film impressed me so much.On 2002-07-18 12:45, Kaptain K wrote:
Thanks Argos.
I have been advocating this (with a catapult first stage and winged scram-jet second stage) since the old board.
Why is NASA so intent on doing it the hard way when SF writers figured this out 60 years ago? [img]/phpBB/images/smiles/icon_confused.gif[/img]
Arthur Clarke also described in a story a magnetic catapult launching vehicles from a lunar base.
Your idea is very interesting. It's really surprising that the US never tried something of the kind.
Order of Kilopi
Talking bout rockets, this is worth a look.
http://www.cnn.com/2002/TECH/space/0...way/index.html
Order of Kilopi
Are you sure that wasn't Robert Heinlein in "The Moon is a Harsh Mistress"?Arthur Clarke also described in a story a magnetic catapult launching vehicles from a lunar base.
It's been a while since I've read any of Clarke's novels, so it may be that he used the idea too.
Established Member
Both Heinlein and Clarke have used mass driver catapults on the Moon in their stories. It's one of the more common elements in SF literature. I'm sure others have used them in stories also.
A mass catapult on the Moon just seems tailor made. The weaker lunar gravity and lack of atmosphere would make them very practical. All you would need to do is get the masses out of the lunar gravity well and they would fall straight down to Earth (assuming you wanted to send them to Earth, but lunar orbit would be just as easy).
I think it would take a very strong catapult to sling objects off the Earth on all on it's own. Maybe even too powerful to be practical, so you don't hear about those as much in literature. The best bet for an Earth-based catapult is probably as a first stage to give it an initial push, with a second stage attached to the object to actually get it into orbit.
How about a ground-based laser acceleration system for the second stage? That would put all of the power sources on the ground and the only extra mass needed on the spacecraft itself would be the reaction mass for the laser. Sling the craft into the upper atmosphere, then focus the laser on the propellent to vaporize it and boost the craft into orbit. Talk about efficient.
Order of Kilopi
Are you sure that wasn't Robert Heinlein in "The Moon is a Harsh Mistress"?
I'm checking KK. It's been a while since I read it, but I'm almost sure that it was a Clarke's short story. I read it in an anthology of his 1950's production. In fact the story wasn't about magnectic launching. But the system was cited in some phrase.
Here's a link to a collection of stories by Clarke. I'm sure i'll find it among one of those under the header Moon Ventures.
http://www.sfsite.com/isfdb-bin/exac...thur_C._Clarke
Anyway, this talk gave me an idea: it will be a pleasure to handle those old volumes again on Sunday.[img]/phpBB/images/smiles/icon_wink.gif[/img]
<font size=-1>[ This Message was edited by: Argos on 2002-07-20 10:42 ]</font>
Member
As it stands right now, these launch rail systems may be more effective in lower gravity environments right now, simply due to the constraints of the acceleration produced by these systems. In a few years however we will be able to get the desired acceleration with a system called indutrack which are composed of of conventional electromagnets that have undergone testing that have a high repulsive capability to reduce gravity to zero due to their placement on the tracks. The last I heard was in a Scientific American article about 2 years ago, they had completed a test indutrack about 30 feet long and the results were very promising for large scale applications say that one of these launching systems would be. They also take very little power as compared to the super-conducting magnets that are needed for the early useage of Maglev's and the prohibitive costs of manufacturing they provided.
Here is an article on the so called indutrack system and how it provides propulsion forces of 400 MphLink here
This idea has been bandied about by science fiction authors since the invention of the high speed locamotive and has persisted to this day where now it is feasible, NASA is now considering such a system but it not likely be realized until the third generation shuttls emerge in about 30 years or more.
-Mark.
Order of Kilopi
Well, as I didn't find the book with the story, and as I still didn't take the time to a more extensive search, let me try to summarize the tale I read:On 2002-07-20 10:36, Argos wrote:
Are you sure that wasn't Robert Heinlein in "The Moon is a Harsh Mistress"?
I'm checking KK. It's been a while since I read it, but I'm almost sure that it was a Clarke's short story.
An astronaut is returning to Earth, after a routine stay on the Moon. He's a pilot of a cargo ship. The ship starts to run the magnetic launching rail. Acceleration mounts. Suddenly he feels a brief pause in the acceleration, but the ship is still on the moving. He takes off the Moon's surface. The only thing is that the pause let him with a speed deficit. He didn't manage to acquire scape velocity. The ship is in Moon's orbit, an unsteady orbit, instead of heading to Earth. He knows that the ship is going to crash on the Moon's surface after some time.
He decides to leave the ship, becoming himself a Moon's satellite, in order to gain an extra time for rescue. He opens the dock and jumps with all the strength his legs can gather. He acquires a higher orbit.
After a couple of orbits he finds out that the jump was not sufficient to send him in a safe orbit. He will also collide with the Moon. He sees the Moon's surface and thinks about its beauty, think about his family, life, and all the things people think in these circumstances. He calculates that he will collide with the lunar Alps. A death in the mountains.
But he is saved by the ship, which was orbiting some miles bellow and shocks with the Alps, one orbit before himself does. The gap in the mountains, created by the collision of the ship, clears out the way for him to perform some extra orbits, until the rescue arrives.
A beautiful Thriller.
I hope one the fellows will recall the name of this story.
<font size=-1>[ This Message was edited by: Argos on 2002-07-22 09:21 to correct spelling and construction errors]</font>
<font size=-1>[ This Message was edited by: Argos on 2002-07-23 13:56 ]</font>
Established Member
Ah yes, Maelstrom II. I thought that might be the one you were thinking about. The BA himself also mentioned it in another thread not long ago. And he couldn't remember the title either, so I looked it up for him.
It's in The Wind from the Sun collection and it was written in 1962. Great little short story.
I think he had mass drivers in other stories as well though. Was there one in A Fall of Moondust? I don't remember.
Established Member
Sure sounds like the movie "When Worlds Collide", which came out in about 1950....spaceship (a classic design of the 30's and 40's) which was catapulted in a long rail.
The objection to horizontal launch that I see, at least for rocket-powered systems, is that your chief goal initially is to get out of the soup...to get as high as you can as quickly as you can so you're not burning up propellent pushing air out of the way. A horizontal launcher goes about in a sort of contrary fashion. You blast along through a field of unchanging atmospheric density, trying to build speed (when speed costs you energy as its square) then you finally turn upward (losing energy again because lift causes drag...) and finally begin your ascent. If you're using airbreathing engines, the penalty isn't so great, but it's bad enough. At least in George Pal's movie, some of the initial velocity came courtesy of gravity...the launch ramp was a ski-jump affair and the booster was a sled that dropped off.
<font size=-1>[ This Message was edited by: roidspop on 2002-07-22 10:49 ]</font>
Order of Kilopi
Bingo! You guys are great. Always ready to shoot.On 2002-07-22 10:45, roidspop wrote:
Sure sounds like the movie "When Worlds Collide", which came out in about 1950....spaceship (a classic design of the 30's and 40's) which was catapulted in a long rail.
I also remember a greedy old man trying to embark with the young, at the end...Pale recollections from the my 70's (the movie was already a vintage then). Very good.
As to the HTHL I think that the system, as described by Clarke et al (the magnetic kind), is specially suited for the Moon, or enviroments which combine low gravity and low atmospheric drag. It could dramatically improve the potential of the Earth-Moon logistics, by reducing costs.
<font size=-1>[ This Message was edited by: Argos on 2002-07-22 12:49 ]</font>
Order of Kilopi
Great, David! Thanks. How could I forget?On 2002-07-22 09:19, David Hall wrote:
Ah yes, Maelstrom II. I thought that might be the one you were thinking about.
Clarke once declared being influenced by Edgar A. Poe. Maelstrom (I) is a masterpiece. Maelstrom II carries the same dramatic tension.
I remember the impression it caused me at first reading (I was 12). I had problems with the fact that the astronaut had to cross the debris cloud raised by the collision of the ship. In real life this could pose a great problem, I thought [I demanded a great accuracy from SF authors those times. I was very tough. I tended to prefer SF based on physical reality (and I still do). I didn’t appreciate too much fantasy in SF (now I do). I hadn’t realized that moment that I was reading the most accurate SF author of all times (slightly ahead of God Asimov, the second most accurate)].
That launching system seemed to me to be perfect, totally compatible with the lunar environment(low gravity, residual atmosphere). I still think it is something worth of a deeper look by the space agencies.
I don’t know for sure. It looks like. Lets check it.I think he had mass drivers in other stories as well though. Was there one in A Fall of Moondust? I don't remember.
<font size=-1>[ This Message was edited by: Argos on 2002-07-22 12:45 ]</font>
Established Member
Nothing to do with launchers, but there was a scene in one of John Varley's short stories (can't remember the title) in which a lunar space station, derelict except for one small passenger and her pets, is in an orbit which takes it with kilometers of the moon's surface...and the orbit is decaying. I recall that the station blasts its way through an obstacle on one of the penultimate orbits. Great story.
Established Member
What's causing the decay in orbit? Orbits around the Earth decay due to atmospheric drag for the most part. But I think the lunar atmosphere is too tenuous to have a major effect.On 2002-07-22 17:51, roidspop wrote:
...in which a lunar space station, derelict except for one small passenger and her pets, is in an orbit which takes it with kilometers of the moon's surface...and the orbit is decaying.
Maybe a solar flare or something could push it out of orbit? But that wouldn't necessarily cause a decay.
Established Member
I suppose you could attribute it to tidal effects; I just suspended disbelief a little harder and enjoyed the yarn.
Member
Anyone ever read Fallen Angels? Man that book gives me the heebie jeebies...On 2002-07-16 06:14, Prince wrote:
http://freedom.orlingrabbe.com/lfeti..._armstrong.htm
Established Member
Haven't read it, but lunar orbits are unstable because of the irregular mass distributions (mascons).On 2002-07-23 01:01, David Hall wrote:
What's causing the decay in orbit? Orbits around the Earth decay due to atmospheric drag for the most part. But I think the lunar atmosphere is too tenuous to have a major effect.
Maybe a solar flare or something could push it out of orbit? But that wouldn't necessarily cause a decay.
Order of Kilopi
Just in case of trouble with acronyms:
http://www.faqs.org/faqs/space/acronyms/
[ This Message was edited by: Argos on 2002-07-17 17:15 ]
Thankyou for that site. I can use it instead of asking what something is when everyone knows but me. [img]/phpBB/images/smiles/icon_biggrin.gif[/img]
Established Member
On 2002-07-23 10:22, Thargoid wrote:
Anyone ever read Fallen Angels? Man that book gives me the heebie jeebies...On 2002-07-16 06:14, Prince wrote:
http://freedom.orlingrabbe.com/lfeti..._armstrong.htm
I've read "Fallen Angel" by W Hjortsberg, and I've read "The Falling Astronauts" by B Malzeberg, but I've never heard of Fallen Angels. Who is it by? And what's it about?
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