Manned Space Missions
Discussion
Now that the Shuttle is no more, maybe we should start a thread to cover launches and developments in respect of the multiple manned spacecraft that are in use or being development.
Spaceflight Now, for instance, are reporting on their website that Boeing's Apollo like CST-100 capsule will be launched by an Atlas V and that they will shortly begin recruiting their astronaut team. They expect the fierst manned flight to be in 2015.
Spaceflight Now, for instance, are reporting on their website that Boeing's Apollo like CST-100 capsule will be launched by an Atlas V and that they will shortly begin recruiting their astronaut team. They expect the fierst manned flight to be in 2015.
Not at all.
These new generation capsules will carry up to 7 people - just like the Shuttle and will be much more flexible and adaptable for all sorts of missions - which the Shuttle was not.
They will also feature non-ablative heat shields and thermal protection systems which means they will be completely reusable.
These new generation capsules will carry up to 7 people - just like the Shuttle and will be much more flexible and adaptable for all sorts of missions - which the Shuttle was not.
They will also feature non-ablative heat shields and thermal protection systems which means they will be completely reusable.
What do you propose?
It's still the best way of geting the energy needed to achieve orbital velocity of 17,500 mph or escape velocity of 25,000 mph.
And modern rockets are more efficient than what we were using 50 odd years ago.
Rocket designs and fuels have not stood still in that time.
It's still the best way of geting the energy needed to achieve orbital velocity of 17,500 mph or escape velocity of 25,000 mph.
And modern rockets are more efficient than what we were using 50 odd years ago.
Rocket designs and fuels have not stood still in that time.
There are alternatives and they are being worked on and tested.
For getting off the surface of the earth and into earth orbit, rockets work best and are (fairly) reliable.
Once in space, there are a couple of options. The best alterntive to old fashioned chemical rockets is ion drive. A number of space probes have used this technique already and it works well. Expect to see more ion drive spacecraft over the next few decades.
For getting off the surface of the earth and into earth orbit, rockets work best and are (fairly) reliable.
Once in space, there are a couple of options. The best alterntive to old fashioned chemical rockets is ion drive. A number of space probes have used this technique already and it works well. Expect to see more ion drive spacecraft over the next few decades.
So it will get seven people into Earth orbit. I say 'so what?' It's not actually any *further* than getting just one person into Earth orbit.
Where does an Atlas V stand in the power stakes compared to Saturn V? Could an Atlas get three men 'to the moon and return them safely to Earth'?
Where does an Atlas V stand in the power stakes compared to Saturn V? Could an Atlas get three men 'to the moon and return them safely to Earth'?
No.
But it will get at least 30 tons or so into low earth orbit.
There is nothing at the moment that will match the Saturn V (7.5 million lbs of thrust at launch). The Shuttle had 6 million lbs - but far too much of that thrust was being used to lift a lot of non-useful stuff into space, such as wings, undercarriage and human life support sytems. If you have 6 million lbs of thrust available, you are much better using it to put actual hardware into space to stay there. It's a right pain putting 30 tons of stuff up there that needs to come back again in a fortnight.
Obviously, the ability to put seven people into space at one time is good - it's what the Shuttle has been doing for decades. Any replacement for the Shuttle should be at least capable of putting the same number of people up in one launch. Soyuz can only place three max.
The big advantages of the capsule designs over winged orbiters are -
they are safer (they can all be fitted with launch escape towers) The Shuttle had virtually no escape system
they are flexible in that the design can be used for low earth orbit, medium earth orbit (over 500 miles in altitude - the shuttle hardly ever exceeded 300 miles) and, with little modification, could be used as the basis of a spacecraft to take humans out of earth orbit (as Apollo could) to the moon and beyond. The Lockheed Martin Orion capsule is designed with all this in mind.
The launching of heavy payloads is best kept for unmanned launchers. There is no need to have humans on board a spacecraft that is being used to put payloads into space. Mixing humans and heavy payloads (as the Shuttle did) gives you a compromised spacecraft that is not good at either task.
But it will get at least 30 tons or so into low earth orbit.
There is nothing at the moment that will match the Saturn V (7.5 million lbs of thrust at launch). The Shuttle had 6 million lbs - but far too much of that thrust was being used to lift a lot of non-useful stuff into space, such as wings, undercarriage and human life support sytems. If you have 6 million lbs of thrust available, you are much better using it to put actual hardware into space to stay there. It's a right pain putting 30 tons of stuff up there that needs to come back again in a fortnight.
Obviously, the ability to put seven people into space at one time is good - it's what the Shuttle has been doing for decades. Any replacement for the Shuttle should be at least capable of putting the same number of people up in one launch. Soyuz can only place three max.
The big advantages of the capsule designs over winged orbiters are -
they are safer (they can all be fitted with launch escape towers) The Shuttle had virtually no escape system
they are flexible in that the design can be used for low earth orbit, medium earth orbit (over 500 miles in altitude - the shuttle hardly ever exceeded 300 miles) and, with little modification, could be used as the basis of a spacecraft to take humans out of earth orbit (as Apollo could) to the moon and beyond. The Lockheed Martin Orion capsule is designed with all this in mind.
The launching of heavy payloads is best kept for unmanned launchers. There is no need to have humans on board a spacecraft that is being used to put payloads into space. Mixing humans and heavy payloads (as the Shuttle did) gives you a compromised spacecraft that is not good at either task.
Edited by Eric Mc on Saturday 6th August 21:47
Simpo Two said:
Hmm, my (wrong )guess was that the Shuttle had more grunt than a Saturn V as it was dragging up a whole 'airliner' as well as seven crew.
Righto, so we take TWO Atlas Vs and strap them together...
Or add on strap-on solid rocket boosters - as they are doing already.Righto, so we take TWO Atlas Vs and strap them together...
If you watched the launch of the Juno Jupiter probe yesterday you would see that they had four smallish strap-on solids. They could add a few more for additional thrust at launch.
Another candidate for a medium-heavy lifter is the Delta-Heavy family.
The Ariane V is not short of grunt either.
None of these rockets will provide the oomph of a Shuttle or Saturn V - but they don't need to. The Shuttle needed 6 million lbs of thrust because it was trying to lift seven people plus all those unecessary things like wings and wheels (and its own engines etc) into space.
The Saturn V was trying to put 30 tons of stuff into LUNAR orbit (it could put 100 tons into earth orbit - which is mighty impressive and something we can't do at the moment).
For regular seven man trips to the space sttation or low/medium earth orbit, you don't need all that lifting capability.
More or less - although it will depend on the strategy you are using to get to lunar orbit and what you plan to do when you get there.
When Apollo was first mooted as a lunar landing mission, the original idea was to have a single spacecraft which would fly directly to the moon, land there, take off, and return to earth. That was called the direct ascent method. The problem was that the spacecraft required was so huge that a REALLY massive rocket (christened Nova) would need to be designed and built.
This picture illustrates the difference in size between a Satutrn I, a Saturn V and a Nova. A Nova would have used up to eight F1 engines as opposed to 5 on the Saturn V. That would equate to 12 million lbs of thrust at launch. No one has come anywhere near to those types of thrust levels - even today.
The final method chosen - Lunar Orbital Rendesvous - was chosen because it gave the most weight savings - which in turn allowed them to use a "smaller" rocket design - the Saturn V.
When Apollo was first mooted as a lunar landing mission, the original idea was to have a single spacecraft which would fly directly to the moon, land there, take off, and return to earth. That was called the direct ascent method. The problem was that the spacecraft required was so huge that a REALLY massive rocket (christened Nova) would need to be designed and built.
This picture illustrates the difference in size between a Satutrn I, a Saturn V and a Nova. A Nova would have used up to eight F1 engines as opposed to 5 on the Saturn V. That would equate to 12 million lbs of thrust at launch. No one has come anywhere near to those types of thrust levels - even today.
The final method chosen - Lunar Orbital Rendesvous - was chosen because it gave the most weight savings - which in turn allowed them to use a "smaller" rocket design - the Saturn V.
Eric Mc said:
The final method chosen - Lunar Orbital Rendesvous - was chosen because it gave the most weight savings - which in turn allowed them to use a "smaller" rocket design - the Saturn V.
Very good sense.I suppose the best option for continued 'extra Earth' missions is to start from a space station, as then you've dealt with the worst bit before you start. We actually have a space station, we just forgot to go any further.
Then again, logic tells me that if you need to get 30 tons to lunar orbit, that 30 tons still has to be lifted from the Earth's surface whether you pause for a bit at a space station or not.
It's a bugger this gravity, isn't it? We need a way to distort it, make a hole so we can go up.
Apollo wasn't really a "sensible" way to go to the moon, It was the most convenient way to go when you don't have any earth orbit infrastructure in place.
The logical way to go is to launch a lunar spacecraft into earth orbit WITHOUT a crew. Launch seapately the lander and dock it with the lunar craft - still without crew. When all is ready, launch your 3 to 7 man capsule - dock it with the combined lunar spacecraft and lander on head for the moon - or Mars, if you are so inclined. You could do these things in conjunction with a pre-existing space station as well - as in 2001 A Space Odyssey.
The manned capsule gives you that flexibility which the Shuttle couldn't.
The logical way to go is to launch a lunar spacecraft into earth orbit WITHOUT a crew. Launch seapately the lander and dock it with the lunar craft - still without crew. When all is ready, launch your 3 to 7 man capsule - dock it with the combined lunar spacecraft and lander on head for the moon - or Mars, if you are so inclined. You could do these things in conjunction with a pre-existing space station as well - as in 2001 A Space Odyssey.
The manned capsule gives you that flexibility which the Shuttle couldn't.
The lunar Saturn V also weighed 1000 tonnes more than the max take-off weight of the shuttle. Shuttle stack power/weight ratio was a good bit better than the Saturn V. The Shuttle was already doing 100mph by the time it cleared the tower, which I always thought was quite impressive for something so heavy.
Gassing Station | Boats, Planes & Trains | Top of Page | What's New | My Stuff