# Why didn't the space shuttle SRBs have wings and tires?

Why didn't the space shuttle solid rocket boosters have wings and tires to land the same way the orbiter lands? I don't think they haven't thought of that so there must be something that led them not to choose that design, right?

• There is no runway in the ocean. – Erik May 1 '17 at 19:01
• It'd be interesting to try to fly them back like remote control airplanes! – Cort Ammon May 1 '17 at 19:59
• @CortAmmon The Russians have had such plans for their Baikal booster for the Angara modular launcher family. – LocalFluff May 2 '17 at 0:19

Wings, engines to fly back to the launch site, and landing gear are heavier than parachutes. Using this design on the SRBs could have resulted in a significant payload to orbit reduction (every 10 pounds added to the SRBs resulted in 1 pound less payload that could be carried to orbit).

However, this was studied for the case of liquid fueled flyback boosters. Another interesting shuttle upgrade that never went through. And, resulting in a crew member comment "I guess we would be 3rd in line for the runway if we had to do an RTLS."

• See Russell Borogove's answer but yes, the original shuttle proposal was for a fully reusable system where the shuttle orbiter launched on a giant reusable manned flyback booster. When NASA was told they had only \$4 billion for development, they changed the design to the expendable tank and refurbishable SRBs (increased operations cost, lower development cost). The flyback LRBs were a later proposal to make the existing system more reusable, only the tank would be expended. – Organic Marble May 2 '17 at 0:14
• Agreed on the third in line quote, that's priceless :) and @ALz, to answer your question about to orbit reduction, that's just a sentence fragment - the meaning can be understood better if you read it as a whole: could have resulted in a significant payload-to-orbit reduction, rephrasing for clarity would give us it could have resulted in a significant reduction in what payload could be lifted into orbit. – flith May 2 '17 at 10:45
• With all new liquid fueled boosters there would be no reduction in payload capability; the new boosters would provide more total impulse than the original SRBs, canceling the drag losses. – Russell Borogove May 2 '17 at 13:54
• It's, let us say, interesting? ...that the flyback booster proposal handwaves away the development of a large RP-LOX staged combustion engine properly sized for the booster. – Russell Borogove May 2 '17 at 14:00
• You'd need to scale up the Merlin about 2x. The Boeing proposal calls for 4x 900klbf engines per booster at 340s Isp which might as well be a flashing sign reading "RD-180". – Russell Borogove May 2 '17 at 15:39

In addition to the booster upgrade proposals that Organic Marble mentions, some early shuttle proposals considered using a single large liquid-fueled winged booster that would fly back to the launch site. The development budget for the shuttle didn't allow that strategy to be pursued.

http://www.nss.org/resources/library/shuttledecision/chapter08.htm

• What an awesome article! – Jason C May 2 '17 at 4:11

It's all about trade-offs. Parachutes are much simpler, lighter, and safer for recovering a "dumb" booster. Wings, landing gear, and control systems add an awful lot of weight (therefore reducing payload) and complexity for pretty much zero return on investment. I also imagine there would've been all kinds of stability problems from adding two extra sets of side-mounted wings to the stack.