Won't you have to use the same system to slow down at the end of your voyage? Does that mean flying through clouds of radioactive particles, etc?
What if Project Orion was launched in the 1970
- Thread starter Jason222
- Start date
Won't you have to use the same system to slow down at the end of your voyage? Does that mean flying through clouds of radioactive particles, etc?
I mostly agree, although I think it's unfair to call it a fantasy. Reading George Dyson's book, the impression I got was that, "built like a battleship" aside, there was a lot of work that remained to be done, and more than one technical issue that could potentially sink the whole project. Shield ablation, shock absorption, and misfire recovery were all major unsolved issues.
If I remember right, there was one projection of Alpha Centauri in 100-odd years.
In a previous discussion of Orion, I brought up Ian's essay on the problems with Orion.
I didn't think any of them were insurmountable, but they were worth considering. For example, triggering the drive too close to Earth would generate an EMP that could destroy satellites.
I didn't think any of them were insurmountable, but they were worth considering. For example, triggering the drive too close to Earth would generate an EMP that could destroy satellites.
My understanding - which may not be correct - is that if you're in vacuum, this won't be a big deal. Direct radiation from the blast should be blocked by the shield. Some of the fallout will pass by the sides of the craft, but between the high speeds everything's traveling at and the need for radiation shielding anyway to deal with solar and cosmic radiation, that's not that a major issue.
No, you don't. You would need landing craft to reach the surface. This is hardly an insurmountable problem, though; after all, Apollo used the exact same technique in the end (even if the CSM was supposed to land on the Moon to begin with, hence the oversized SPS engine, for lunar takeoff). The most difficult target would be Mars; Titan could easily be handled by something using parachutes and heat shields, like on Earth, and other moons are airless and hence not very difficult to build landing craft for. Mars is right where the air is thick enough to be annoying but not thick enough to be very helpful, unfortunately.
For that matter, pretty much all modern plans to go anywhere in the solar system use landing craft themselves, if for no other reason than the usual cost (in delta-V) of landing on and then taking off from a planet. the major exception is Mars, and even then a number of NASA's post-DRM Mars proposals do it...
Jason222
Banned
Single Saturn V rocket modied can carry object was 169,950 pounds. Ship mass be about 10,000 t. Not include fact likley want a space station able both build thing and did repairs. So it take something like 30 rockets for bomb-lets and everything. Into day money cost 1.7 billion dollar launched so just getting space would cost 40 billion dollars another 40 billion dollar into day money in research and development and build much as possible on ground. 80 billion dollar into day money. If split between USA and USSR it be 40 billion dollar piece not unheard spending. It mean cutting some military spending but nothing neither country could not afford to do. Russia to day afford to if well devote must resource into it. USA has multi trillion dollar defense budget. For interplanetary mission I say decade. It likley 1980's when launched to the nearest star system.
For all guy argue the Orion Project not getting up 10% speed of light you forgetting something how powerful the nuclear bomb is going to make different and if manned or not. If using H bombs should getting up 10% speed light if using A bomb more like 3% speed light. This guessing do not find ways build H bomb lighter and more powerful after they doing Orion interplanetary mission which is possible mission stars. Point going to learn thing never learn came interplanetary flight and so Interstellar flight big unknown might able get 10% speed light unmanned mission or they might get 20% speed of light.
For all guy argue the Orion Project not getting up 10% speed of light you forgetting something how powerful the nuclear bomb is going to make different and if manned or not. If using H bombs should getting up 10% speed light if using A bomb more like 3% speed light. This guessing do not find ways build H bomb lighter and more powerful after they doing Orion interplanetary mission which is possible mission stars. Point going to learn thing never learn came interplanetary flight and so Interstellar flight big unknown might able get 10% speed light unmanned mission or they might get 20% speed of light.
True enough. Whatever radiation Orion puts out is nothing compared to what the cosmos will throw at you.
Indeed; getting stuff INTO orbit is the hard part. The only trick to reentry is survival of the human crew, which I should hope a nuclear missile would not have.
If I remember correctly, Orion was planning on using fairly small nuclear charges (most plans I've seen use yields of about 10 kilotons, and I've seen mentions of sub-kiloton yield), which would help mitigate the EMP effects. Also, EMP is usually only very bad if done within specific altitude range. The Starfish Prime test (the one that fried a bunch of satellites) had a yield of about 1.5 megatons, at what was pretty much the optimum altitude to produce an electromagnetic pulse.
All the Orions on Wikipedia (except the interstellars) used sub-kiloton warheads--Davy Crockett-types, W54s. 800 of them to orbit, though. Even so, it's only 1/5 of Starfish Prime's yield, and only a few of them will be going off at 400 km. Such a small yield, if launched from somewhere in the Pacific, should minimize risks (maybe a sea-launched first stage to get it up past the troposphere would be in order, to minimize fallout).
Ian's essay had other objections, but it seems to have vanished--the link to it on Wikipedia no longer functions.
I had always assumed that a chemical first stage would be used to get the vehicle far enough off the ground that the fireball won't hit the ground. This gives a fireball diameter of only about .02 km for a 1/2 kiloton detonation, but I'd still probably want to get it up to a kilometer or so. For reference, an AIR-2 nuclear tipped rocket with a 1.5 kiloton yield was tested in 1957 at altitude of 20,000 feet, and unprotected observers under the blast were completely fine.
Wiki lists the interplanetary Orion as having a mass of 4,000 tons, compared to a Saturn V with 3,350. So I think using chemical propulsion to lift it off the ground is definitely technologically feasible in the present to near future.
Sub-kiloton warheads reduce the fallout from fission products, but it is a colossal waste of fissile material, which is spread widely around.
--
Orion being capable of reaching 10% of c is a joke, at best.
If all energy in a deuterium-tritium mix were perfectly turned into thrust, then the exhaust velocity would be ~26000km/s. To reach 30 000km/s the ship would need a mass ratio of 3.17. If the ship is supposed to slow down, it means 3.17^2 = 10.05, or 90 f-cking percent of the ship must be 100% efficient fusion fuel, if it is supposed to accelerate up to 10% of c and down again!
It would mean a warhead yield of 75.5Kt/kg of such fuel. I challenge you to find a warhead that exceeds 1/10 of that. Also, since it is an explosion, achieving an efficiency of 50% of the energy ending up as thrust is probably very optimistic.
http://en.wikipedia.org/wiki/W88
475Kt, 300-something kilograms.
I skimmed this article like 10plus years ago, but I seem to recall that the 10% was suggested for a Orion drive probe, that would do a flyby of Alpha Centari, so there would be no slow down.
Does that work?
Motive for making such an expensive probe? Who would spend money on it when the same amount of money can bring more tangible research results within Solar system in a fraction of time?
NothingNow
Banned
They were also focused charges to increase efficiency. That'd also seriously cut down on the spread of the EMP.
Basically no, if more realistic numbers are used then the mass ratio is much worse.
Also, it would have to be very, very "heat-efficient", (not absorbing the energy released to propel it) to achieve 0.1 c over only 4.33 light years, again I doubt it is possible.
amphibulous
Banned
No. The particles will be moving faster than you and this will never change - no atmospheric drag, yes?
amphibulous
Banned
Star Trek fans. Especially if you put a picture of Spock on the side of the probe - just look at all those collectable plates they buy.