You are not logged in.
If you want something based on fact, you have to acknowledge the reality that manned space-flight beyond LEO, like supersonic travel, is a thing of the past.
Nobody has been beyond LEO in the lifetime of most people currently alive. Is it any wonder that so many of them don't believe it happened in the first place. After all, why would we stop going to the moon?
If you get a chance to see the program do so. It is entertaining and contains input from proper scientists (not simple engineers like me).
Offline
If you want something based on fact, you have to acknowledge the reality that manned space-flight beyond LEO, like supersonic travel, is a thing of the past.
Nobody has been beyond LEO in the lifetime of most people currently alive. Is it any wonder that so many of them don't believe it happened in the first place. After all, why would we stop going to the moon?If you get a chance to see the program do so. It is entertaining and contains input from proper scientists (not simple engineers like me).
Well thats silly, nobody doubts the reality of flight to Earth orbit, so why would travel beyond it be a magically impossible task? No, people who doubt Apollo took place, I relegate to the lunatic conspiracy theory fringe.
And "why did we stop going to the Moon" is the wrong question to ask, the real question is why did we go there in the first place at all. There are several reasons, science, national engineering stimulus, but all these are meaningless compared to "showing up the Commies." Which we did... so, there was no good reason to keep going to the Moon beyond Apollo-11 other then to show it wasn't a one-off lucky fluke, which we did that too.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
S =1/2at squared = 5 times 10 billion meters = 50 million kilometers, which is about the half the distance between each of the 4 inner planets, in a favorable lineup. The acceleration is slightly more than one g, which should be doable contineously with an advanced fusion motor. The square root of 10 billion is 100,000 seconds = 27.777 hours. Besides accelerating 3 times to visit 4 planets we need to decelerate 3 times = 166 hours which is 2 hours short of one week, so a month total allows an average about 6 days lay over and manuver time at each planet. It will not take much longer to visit the remaining 5 planets, because of the wonder of square law = less than a year even with least favorable allignment, and stopovers at several moons. Neil
Offline
Sure, you just need a billion tonnes of fuel to make such a trip
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Hi DaytonKitchens: We could have 4 SE = space elevators by 2025, if we get strong and cheap CNT = carbon nano tubes soon. SE 4 could be more than 100,000 miles from center of Earth to the tip. C = 6.28 times 100,000 = 628,000 miles per day. The Sun's gravity will slow the average speed to about 500,000 miles per day for 1000 days = 500 million miles which will get us to Jupiter. About 1500 days to get us to Saturn, instead of Jupiter. SE 4 may be able to flip 100 tons toward the gas giant planets. 100 tons is marginal for that long a manned trip as considerable fuel is needed to make a soft landing on a moon, if the slow down manuver around the gas giant planet is unsucessful. There may not be enough fuel (even with a sling shot manuver around the gas giant) to make the return trip in ten years travel time, which is way too long unless supplies can be produced on that moon = not very likely. We can get there, but surviving the return trip is unlikely. Neil
Offline
Now that I have read several other threads on this topic, I reilize you are thinking six humans instead of three. My guess is we need to wait for SE5 which may be able to flip 150 tons, and could be as long as 200,000 miles. That doubles the speed to get you to Jupiter in 500 days, which leaves more supplies for a stop over, and the return trip which could take more than ten years with bad luck. Three persons in each of two ships means improved safety factors and rescue is possible, if not probable. 200,000 miles means the counter weight needs to be on the Earth side of GEO altitude, so we might shorten SE5 after the Jupiter launch and a few others requiring high speed. The good news is SE5 might be completed as soon as two years after SE3 is complete (one year after SE4) with sufficient demand for heavy lift. Neil
Offline
The vessel detailed in the broadcast and book does indeed use a fusion engine and prepositioned fuel stocks around the solar system.
IIRC, the Venus manned lander is built alot like a deep sea submarine while the lone astronaut to venture out wears a spacasuit similiar to a deep sea divers suit to withstand the heat and pressure.
Also, the Io lander does have superconducting magnets to help shield the astronauts from the intense radiation.
One must consider that the mission outlined had to be made so it would look good on television. Perhaps that is the reason for the short stay times on each world and the relatively small crew.
A vessel as large and sophisticated as the Pegasus shown in "Voyage To The Planets" could probably support a crew of at least a dozen and stay times of months rather than days at each target planet.l
I've wondered if maybe we're thinking about manned space exploration to the planets the wrong way. Instead of constantly trying to reduce mass, cut costs everwhere possible, perhaps a large "Battlestar:Galactica" approach might be better.
I think your right with the Battlestar Galactica approach. The proper way to approach exploration of the solar system seems to be to build the ships in orbit.
While it provides some complex challanges are far as construction, it provides much more freedom in design. It also makes them reuseable and available for other missions as needed. In the long run, it may also keep costs down after the initial infrastructure it in place. It will also foster a continued heavy presence in space.
Offline
,l
I'm appalled at the lack of interest or even conversation ANYWHERE that I can find about possible manned missions to the gas giants.
Aside from the HOPE site, there appears to be not even talk about such missions.
I think the trouble is no one seems willing to make the commitment in life support technologies needed for the jump to the multiyear transits. All the buzz surrounds get to Mars with the least amount of effort as possible, which I fear will have disasterous results. We are fighting tooth and nail to get out of LEO for what most is hoping to be a short detour to the moon, followed by more downtime for a very limited mission to Mars. Anything beyond that would require more downtime to invent entirely new architecture for anything beyond.
I favor a long term build up on the moon to develop all the long term quasi self sufficent LSS needed for the decade long voyages long before we go to Mars. There should only be one jump, from near Earth Space to interplanetary space, and it should be done on the Moon. And while we are there we can do all the surface activities that we will do anywhere else.
I believe your right. One shot missions, in the long run, are just too expensive. A comprehensive system is needed. It will have to be among all the space faring natiions and will require long term commitment.
The first phase should be reliable, low cost boosters to haul the initial equipment to Geostationary orbit to build a space complex, from this station, going off to the moon or the planets will be much easier.
The second phase should be a detailed examination of the moon to determine what raw materials there can be used for fuel, building materials and the like.
If the material is available, a permanent base would be built. Other small spacraft would be built to shuttle crew, finished "moon products" and other resources between the moon and the GSO station. An additional benifits would be an observatory on the far side of the moon.
The final stage of the project would be the interplanatry vehicles themselves. With out having to fly out of the earth gravity well, travel will be much easier, and cheaper. More than one craft can be built to carry out multiple missions or large missions.
Offline
Hello and welcome keithconto
The issue with orbital assembly and of using space stations as platforms for going to other places comes back to the question of where do you get fuel for the rocket once built and of the increased levels of need required by the use of a station.
Offline
Well, then its a good thing nobody is going to suggest using mostly expendable ships in the "long run."
In the short run though, before we are ready to do anything more than exploration and "beach head" building, smaller mostly expendable vehicles make good sense.
So-called "comprihensive systems" with "all the spacefaring nations" is a Star Trek pipe dream. We'll never get along politically enough nor engineering wise enough. There is no one-size-fits-all solution, that the best way to get to the Moon and Mars with and without a base are different, and since a large "comprihensive" system takes a much bigger commitment than the smaller one, which makes it more likely travel to these places will actually start.
GEO orbit is way too high, there are presently no practical alternatives to chemical rockets to get into orbit, and so you want to rely on these as little as you can versus more efficient engines (ion, nuclear thermal, etc). This means the lower the orbit the better, plus you can't aerobrake into GEO.
Why will building a space station make travel much easier? You still need the same amount of rocket fuel, which is the real problem. The issue is where you get the fuel from, that if all or at least a majority of the propellant needed for landing and return is made from the destinations, then you save huge amounts in launch costs.
Just building a space station doesn't give you this, so the first priority should instead be to build fuel depots on Moon/Mars. One we have these, and we are ready to do more than explore the inner solar system, then we can talk about reuseable launch vehicles and space stations, but not before.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
I don't think the sheer amount of time required for a Grand Tour mission makes it possible by itself. I doubt any astronaut will willingly sacrifice half his/her lifetime for something a fly-by mission or a set of landers/rovers could do. It isn't practical by any current standard or technology eithier.
Until propulsion capability can bring a trip to Mars down to within two months anything further than Jupiter for manned spaceflight is logically impossible for humans. I think it'd have to be something more powerful than nuclear rocketry as well. The whole Voyage to the Planets TV special while vaguely cute came off as rather insane to me.
Offline
Advanced nuclear engines could do the job. Either the GCNR or NSWR engine could get you from Earth to Mars in a month or two flat with a reasonably sized vehicle.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Hello and welcome keithconto
The issue with orbital assembly and of using space stations as platforms for going to other places comes back to the question of where do you get fuel for the rocket once built and of the increased levels of need required by the use of a station.
That will depend on the type of propulsion. The scenario I was describing would not be carried out with conventional rockets. Alot of it depends on the inventory of resources on the moon. If available, the cost of resources from the moon, in terms of ease of launch, would be far cheaper. The system would depnd on the ability to " live off the land" get your fuel and other resources where your going, or where you are. Better environmental systems are needed. As I said, this would be a long term plan. But would ensure our continued presence in space.
Offline
Well, then its a good thing nobody is going to suggest using mostly expendable ships in the "long run."
In the short run though, before we are ready to do anything more than exploration and "beach head" building, smaller mostly expendable vehicles make good sense.
So-called "comprihensive systems" with "all the spacefaring nations" is a Star Trek pipe dream. We'll never get along politically enough nor engineering wise enough. There is no one-size-fits-all solution, that the best way to get to the Moon and Mars with and without a base are different, and since a large "comprihensive" system takes a much bigger commitment than the smaller one, which makes it more likely travel to these places will actually start.
GEO orbit is way too high, there are presently no practical alternatives to chemical rockets to get into orbit, and so you want to rely on these as little as you can versus more efficient engines (ion, nuclear thermal, etc). This means the lower the orbit the better, plus you can't aerobrake into GEO.
Why will building a space station make travel much easier? You still need the same amount of rocket fuel, which is the real problem. The issue is where you get the fuel from, that if all or at least a majority of the propellant needed for landing and return is made from the destinations, then you save huge amounts in launch costs.
Just building a space station doesn't give you this, so the first priority should instead be to build fuel depots on Moon/Mars. One we have these, and we are ready to do more than explore the inner solar system, then we can talk about reuseable launch vehicles and space stations, but not before.
Interesting GCN.
You know a great deal about propulsion systems.
If you were called on to design an interplanetary spacescraft to take a dozen or so astronauts to multiple planets in a single multi year mission........what do you think you would end up designing?
Offline
Me? Hmmmm... as far as more-or-less present propulsion goes, you have basically three options:
-Gas Core Nuclear Rocket (GCNR)
~3000-5000sec ISP
~Uses Hydrogen for propellant
~No special fuel tank required
~Fuel tank is still bulky
~Engine is relatively light weight
~Uses small amounts of nuclear fuel
-Nuclear Salt Water Rocket (NSWR)
~10,000sec ISP(?)
~Uses water laced with Uranium for fuel
~Requires special neutron-absorbing fuel tank
~Fuel tank is compact
~Uses lots of nuclear fuel
~Engine requires heavy blast shield/pusher plate
~Would only require a fuel heater
-VASIMR (Variable specific impulse magnetoplasmic rocket)
~10,000sec ISP
~Uses Hydrogen for propellant, consumes no Uranium
~Bulky fuel tank
~Only moderate thrust, bad maneuver/departure
~Requires massively powerful but light nuclear reactor
~Generates lots of excess electricity when not firing
~Engine itself is heavy due to magnets, cooling
~Questionable reliability due to complexity
~Generates powerful magnetic field, may shield the ship
Neither engine really has sufficent performance for a trip to all the outer planets with a single load of fuel, but if refueling at each destination were employed then you could do it in a reasonable time frame provided you didn't stay at each destination too long. The ship would retain enough fuel for an abort back to Earth at all times.
Which engine you use depends, a GCNR or VASIMR engine would need to break down water into Hydrogen and liquify it but would have to lug little Uranium and its performance is so-so for this kind of a trip (GCNR lower efficiency, VASIMR lower thrust). An NSWR engine has much more kick to it and would only need liquid water, but refueling at each stop would be less effective due to the mass of Uranium salt required, so its a trade off.
For this duration of a mission, a ship full or partially spinning would probably be a must. Perhaps a combination of RLV and Ares-V class flights:
Ares rockets bringing up the "engineering" section, the manned "core" section, and the workshop/storage/instrument section. It would also launch two chemical-fueled landers.
The RLVs, probably two-stage spaceplane, would deliver:
-the fuel tanks, or just water in NSWR
-bolt together ring compartments, unfurnished
-two pressurized tunnels connected to the "core"
-supplies, furnishings, space suits, tools, and probes
-airlock (if seperate from workshop)
-emergency reentry vehicle (in case Earth capture fails)
-uranium for NSWR, or radiators for VASIMR
-water collection equipment for refueling
The engineering section, containing the engine, power reactor, and fuel condenser (in GCNR & VASIMR) would be mated end-to-end with the "core" module and finally the workshop/storage/etc. The core itself would be heavily radiation shielded and contain the command equipment/life support/etc and ports for the ring tunnels and ancilliary modules. The workshop/storage section would contain the science & surface gear as well as docking facilities for the landers.
The ring would have thin, fairly small spaces probably little larger than a train car to minimize the mass as it will have to be fairly wide to negate the coriolis force to any degree. I envision a crew of six to eight each with their own cabin (with extra rad-hardend bed)/office, some laboratory spaces, galley and so on. Since the ring will be wide for the coriolois force, it will probably have excess volume where bulk foodstuffs would be kept.
In the event of a solar storm or when traveling through Jupiters' radiation belts, the crew would have to stay in the heavily shielded core section for the duration probably, but the ship could perhaps spend most of its time on the outermost Gallilean moon that resides outside these belts.
The ship itself will be capable of landing tail-first, which should be easy on slow turning moons with low gravity, in which case the ring will stop its roation probably and landers parking nearby until the ship reenters orbit. It will land to make gathering up water for refueling easier and skip having to shuttle it back and forth from the mother ship. The VASIMR's magnetic field is kinda attractive though.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
Me? Hmmmm... as far as more-or-less present propulsion goes, you have basically three options:
-Gas Core Nuclear Rocket (GCNR)
~3000-5000sec ISP
~Uses Hydrogen for propellant
~No special fuel tank required
~Fuel tank is still bulky
~Engine is relatively light weight
~Uses small amounts of nuclear fuel-Nuclear Salt Water Rocket (NSWR)
~10,000sec ISP(?)
~Uses water laced with Uranium for fuel
~Requires special neutron-absorbing fuel tank
~Fuel tank is compact
~Uses lots of nuclear fuel
~Engine requires heavy blast shield/pusher plate
~Would only require a fuel heater-VASIMR (Variable specific impulse magnetoplasmic rocket)
~10,000sec ISP
~Uses Hydrogen for propellant, consumes no Uranium
~Bulky fuel tank
~Only moderate thrust, bad maneuver/departure
~Requires massively powerful but light nuclear reactor
~Generates lots of excess electricity when not firing
~Engine itself is heavy due to magnets, cooling
~Questionable reliability due to complexity
~Generates powerful magnetic field, may shield the shipNeither engine really has sufficent performance for a trip to all the outer planets with a single load of fuel, but if refueling at each destination were employed then you could do it in a reasonable time frame provided you didn't stay at each destination too long. The ship would retain enough fuel for an abort back to Earth at all times.
Which engine you use depends, a GCNR or VASIMR engine would need to break down water into Hydrogen and liquify it but would have to lug little Uranium and its performance is so-so for this kind of a trip (GCNR lower efficiency, VASIMR lower thrust). An NSWR engine has much more kick to it and would only need liquid water, but refueling at each stop would be less effective due to the mass of Uranium salt required, so its a trade off.
For this duration of a mission, a ship full or partially spinning would probably be a must. Perhaps a combination of RLV and Ares-V class flights:
Ares rockets bringing up the "engineering" section, the manned "core" section, and the workshop/storage/instrument section. It would also launch two chemical-fueled landers.
The RLVs, probably two-stage spaceplane, would deliver:
-the fuel tanks, or just water in NSWR
-bolt together ring compartments, unfurnished
-two pressurized tunnels connected to the "core"
-supplies, furnishings, space suits, tools, and probes
-airlock (if seperate from workshop)
-emergency reentry vehicle (in case Earth capture fails)
-uranium for NSWR, or radiators for VASIMR
-water collection equipment for refuelingThe engineering section, containing the engine, power reactor, and fuel condenser (in GCNR & VASIMR) would be mated end-to-end with the "core" module and finally the workshop/storage/etc. The core itself would be heavily radiation shielded and contain the command equipment/life support/etc and ports for the ring tunnels and ancilliary modules. The workshop/storage section would contain the science & surface gear as well as docking facilities for the landers.
The ring would have thin, fairly small spaces probably little larger than a train car to minimize the mass as it will have to be fairly wide to negate the coriolis force to any degree. I envision a crew of six to eight each with their own cabin (with extra rad-hardend bed)/office, some laboratory spaces, galley and so on. Since the ring will be wide for the coriolois force, it will probably have excess volume where bulk foodstuffs would be kept.
In the event of a solar storm or when traveling through Jupiters' radiation belts, the crew would have to stay in the heavily shielded core section for the duration probably, but the ship could perhaps spend most of its time on the outermost Gallilean moon that resides outside these belts.
The ship itself will be capable of landing tail-first, which should be easy on slow turning moons with low gravity, in which case the ring will stop its roation probably and landers parking nearby until the ship reenters orbit. It will land to make gathering up water for refueling easier and skip having to shuttle it back and forth from the mother ship. The VASIMR's magnetic field is kinda attractive though.
You sure know your stuff.
I've got to print that out.
Offline
Finally got to revisit this, Football season is finally over so I have alot more spare time.
I was wondering. If the sleeping quarters of a rotating interplanetary spacecraft as I'm envisioning here were kept at 1G, then how much additional exercise would the crew have to do to prevent bone mass loss given they would be spending at least say 10 hours or so under the influence of 1G?
Offline
Another use for flywheels. Power storage and art-G
Offline
I'm not sure of the forum rules on reviving old threads and this is among the oldest I've ever revived on any forum about any subject. But I've become intrigued again by the "manned multi planet expedition" concept again.
Offline
Not a problem Dayton3 as you have not been here in quite some time to post on the forum, some things have changed a bit but the number of topics have not slowed as we still work towards and want to go to mars one day.
Offline
It seems to me that any multi planet manned mission to the outer solar system would have to include Jupiter on the first leg of any of them.
Thus for the first Voyage to the Planets type of mission you might have
1) Jupiter (Callisto landing)
2) Saturn (Triton landing)
3) Pluto (planetary landing).
For the second Voyage to the Planets type of mission you might have
A) Jupiter (Ganymede landing).
B) Uranus (Titania landing)
C) Neptune (Triton landing).
The third Voyage to the Planets type of mission might have
A) Jupiter (Europa landing)
B) Mercury (planetary landing)
C) Venus (manned penetration of planetary atmosphere).
I assume the manned Mars program would be separate for obvious reasons.
Offline
Hubble monitors changing weather and seasons at Jupiter and Uranus
Offline