Friday, December 20, 2019

off target

Oh dear. Learned that the Boeing CST-100 Starliner has gone off course. It won't reach the space station... Wow. I'm not clear yet if it was a problem with the launcher or with the spacecraft proper.

I did some quick analysis of the live stream reporting from Spaceflight Now. Sounds like the United Launch Alliance Atlas 5 rocket with RD-180 engine performed nominally as did the two strap-on solid rocket motors by Aerojet Rocketdyne. This is a proven, very successful launcher with 80 flights. They took off without a payload shroud. To improve on aerodynamics, a skirt was added to the bottom of the Starliner.

It also seems like the two RL10A-4-2 engines on the Centaur upper stage worked as expected. This was an updated design with dual motors. Not entirely unique, just not mated with the Atlas 5 previously.

The CST-100 was placed into a suborbital trajectory. The shallow path reduces g-forces for cabin occupants and supports abort options. Not dissimilar to the profile used in shuttle missions. But it also means the Starliner has some work to do still, to raise and refine its orbit.

The Starliner spaceship service module has four Aerojet Rocketdyne engines on-board for orbital maneuvers and attitude control. And it appears that something went wrong at this stage.

Reports suggest it used a lot of fuel to reach a stable orbit which leaves an insufficient supply to reach the ISS. They'll have to scratch docking and associated tests and go straight to landing in New Mexico.


Boeing has a lot to prove.

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