Don't think anyone mentioned this yet, but wings are pretty reliable compared to rocket engines. Wings are simple chunks of metal with few moving parts, whereas rockets are complicated chunks of metal with lots of moving parts.
Quote from: antiquark on 02/22/2012 06:29 pmDon't think anyone mentioned this yet, but wings are pretty reliable compared to rocket engines. Wings are simple chunks of metal with few moving parts, whereas rockets are complicated chunks of metal with lots of moving parts. On the other hand it's easier to design for engine-out than for wing-out.
{snip}Another is that wings are generally pretty heavy and are only really very good at returning from LEO. Do we really want to be restricted to only returning from LEO?
The title asks:"What are advantages and disadvantages of powered and aerodynamic landing?"One of the advantages of powered landing (vs aerodynamic) is that it can be done at places other than Earth. To artificially exclude the rest of the solar system is to deny one of powered landing's best advantages. We're going to have to get good at powered landing anyway.Another is that wings are generally pretty heavy and are only really very good at returning from LEO. Do we really want to be restricted to only returning from LEO?
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.