The Space Launch System, which recently secured funding from Congress, uses many features that were developed from the Shuttle program, including the first-stage engines and boosters, and it's overall design looks strikingly similar to the Saturn-V launch vehicle. Obviously this is fine because these technologies have been proven to work.

What are the capabilities or technical differences between the SLS boosters and those used by the Shuttle? The wiki page describes the boosters used by the SLS, but I would like to know more about what the upgrades are.


1 Answer 1


There are at least three major differences.

  1. No parachutes for recovery. Saves a bunch of mass.
  2. One extra segment. Shuttle used 4 segments, SLS will have 5 segments.
  3. Fuel change. The details are murky but they upgraded the specifics of the fuel being used.

Sadly, when you change from 4 to 5 segments, you lose most commonality with the shuttle boosters. A Solid Rocket has no real thrust control (you can steer the nozzle a bit, but at 2.8 million lbs of thrust, not that much) so most of the control is done by profiling the shape the of propellant on the inside, to control the pattern in which it burns.

Thus a 4 segments internal profiling of the propellant does not really resemble the 5 segments internal profiling. Thus a lot of the flight history is thrown out by this change. The external stuff is similar (same casings, joints, nozzle, etc) but the tricky part is the internal profile to control the thrust.

  • 1
    $\begingroup$ The internal profiling is also referred to as the "grain" $\endgroup$
    – Nickolai
    Jan 21, 2014 at 19:40
  • 1
    $\begingroup$ @Nickolai Thanks! I was grasping for the right word there, $\endgroup$
    – geoffc
    Jan 21, 2014 at 20:20

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