09/16/2021 – Ephemeris – How safe is the Space Launch System (SLS) compared to the Space Shuttle?

This is Ephemeris for Thursday, September 16th. Today the Sun will be up for 12 hours and 27 minutes, setting at 7:51, and it will rise tomorrow at 7:24. The Moon, 3 days past first quarter, will set at 3:10 tomorrow morning.

Tonight, the planet Saturn will appear above the bright gibbous Moon. It might be a bit hard to spot.

The big NASA moon rocket, the Space Launch System or SLS, borrowed a lot of features from the Space Shuttle. Is it any safer? The answer is yes. The Space Shuttle had no abort system for a catastrophic failure, as we saw with the Challenger accident in 1986. However, even though the SLS uses the same type solid rocket boosters that failed Challenger, the Crew in the Orion capsule is on top of the rocket with an escape system to rocket them away from an exploding core stage. With the Orion capsule, the escape tower will be jettisoned at some point before reaching orbit, possibly making escape impossible in the latter stage of powered flight. Both SpaceX’s Dragon and Boeing’s Starliner have escape rockets built in for the entire flight.

Addendum

Shuttle-SLS comparisons. Note that this image is 10 years old. The center core stage will, like the external tank on the shuttle, remain unpainted. So far, the cargo version of the is still in the design stage. The Multipurpose Crew Vehicle is now called the Orion Spacecraft. Credit: How Stuff Works.

Phil Plait has a great video of the STS133 Launch

From Phil Plait’s Bad Astronomy blog comes a great Video taken from several cameras on the solid rocket boosters (SRBs).  The greatest sight for me was to see from the aft cameras the shuttle orbiter and the fuel tank depart after the SRB’s were jettisoned.  Here’s a screen cap from the left aft SRB camera.  Check out the entire video.  There’s only one or two launches left.

STS133 orbiter and fuel tank leaving the booster behind

Image credit NASA.