It's a trade that depends on many factors and one that definitively will not be answered on this thread.
...I am not artificially excluding the rest of the Solar System. The title "What are advantages and disadvantages of powered and aerodynamic landing?" is meaningless applied to bodies without an atmosphere. Such bodies are automatically excluded from such a discussion. And of course we are going to have to use powered landing for them.
What are advantages and disadvantages of powered landing (future Dragon) and aerodynamic (Space Shuttle, Dream Chaser) landing types?For example, let's assume I have a factory at LEO , and I need to transport product from LEO to Earth, and also to move workers up and down (just a thought experiment).
This looks extremely difficult for a whole variety of reasons. I can see the first and second stages having enough fuel left to make the return journey, but I can't imagine that there would be enough room in the Dragon for the fuel required for powered descent.
I thought they would go with a combination of parachutes to slow Dragon, then the Super Dracos for the last 30 or 40 thousand feet.
BTW: Has there EVER been a spacecraft that has returned from Earth orbit using powered descent all the way to the surface?
Quote from: douglas100 on 02/22/2012 11:05 AMOne advantage of wings that has been mentioned is a potentially softer landing for ISS crew after 6 months on orbit. The Soyuz landing is pretty brutal.But there's no reason a powered landing can't be gentle -- consider the Apollo LM, for example.
One advantage of wings that has been mentioned is a potentially softer landing for ISS crew after 6 months on orbit. The Soyuz landing is pretty brutal.
Soyuz 1 hit the ground at less than 100mph with tangled drogue and reserve 'chutes. So if it's only terminal velocity you have to break against, you're probably talking about less than 10% of the re-entry mass needing to be propellant, wings would weigh more than that, heat shield is still required with both methods.
IIRC I saw a web page that described some early designs of the Russian shuttle before it was decided to use the Buran design.The preferred design was a lifting body that used rockets for landing, I'll try to find it again.
Thank you for your answers!I was thinking about transportation between factory in LEO (space station in LEO) and Earth, not other planets (I cannot imagine why we will have a lot of traffic from other planets/Moon soon).Actually, I was trying to find out what types goods can be manufactured in space, which would justify such venture.Surprisingly, I couldn't find any information about how much would be price of kg of something transported from LEO to Earth. It seems that nobody ever made even a paper-spacecraft, designed to bring goods from orbit to surface; spacecraft that is designed to be launched empty (and refueled in orbit if it uses powered landing), and return with cargo.With current launch prices, I guess, only mining gold and platinum from asteroids will close the business case, but if the price can be less than 100$ per kg down, we have more options.
The first thing to manufacture in space is perhaps spacecraft. After all - they are so valuable that it is worth the cost of launching them to orbit.Steve
As for thought experiment of a factory in space. I am guessing you mean something which doesn't high volume- making drugs or something with low mass but is valuable. So perhaps 10 tons per year shipped to earth per year? With increase possible, perhaps to say 100 tons per year?
If whatever you shipping from space to earth surface can withstand high gees- it's cheaper. 50 gees is a car accident. If payload can withstand over 100 gees, "landing" is more like a controlled crash. A controlled crash into a lake, could something with fairly high terminal velocity. And one major aspect is the accuracy of hitting say 10 sq kilometer area.Normally, one want re-entry which is lifting body- to reduce gees [and heat- though heat isn't as challenging as gee loads].
The first thing to manufacture in space is perhaps spacecraft. After all - they are so valuable that it is worth the cost of launching them to orbit.