Why have SpaceX, Boeing & Blue Origin ditched abort towers?

There’s a new trend going around in the commercial space industry when it comes to launch abort systems. All three commercial companies who are putting abort systems on their crewed vehicles have ditched the classic launch abort tower we’ve seen dominate abort systems in the past.

Previous vehicles like the Mercury capsule, the Apollo capsule and even the Soyuz all used an escape tower that sat on top of the crew module, capable of pulling the vehicle away from a failing rocket in a hurry.

And to make this topic even more interesting, we’re seeing another trend in abort systems... SpaceX’s Crew Dragon and Boeing’s Starliner capsules both are using liquid fueled abort motors instead of solid rocket motors.

So today we’re going to talk about the design considerations that have made SpaceX, Boeing and Blue Origin ditch abort towers on their crewed vehicles and we’re also going to evaluate why the heck Boeing and SpaceX are going with liquid motors instead of solid motors.

And with both Boeing and SpaceX having experienced serious setbacks and complications with their liquid fueled abort systems, including the loss of a test vehicle, it raises the question… is it even a good idea?....

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This video had four "Moon Walkers" who helped make this possible - Blake Jacobs, Mac Malkawi, Eli Burton and Ole Mathias Aarseth Heggem.

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[Awol]

Rocket Science: Pointy end up. Flamey end down.

[HPD]

4:20 this is such a kerbal solution.
"well does it get the capsule away from the boom?"
"er yes... but.."
"then so what if it wobbles a bit"

[icbmrick]

Him: “15 g’s”
Ksp players: “you gotta bump those numbers up, those are rookie numbers”

[CreamyYT]

Tim Dott 2019: The Crew Capsule will never been reflown for Crew
SpaceX 2021: Uses for Crew 2 the same Capsule as for Demo 2

[maxcchiru]

I bet that Orion Attitude Control Unit was tested by someone sitting there like with KSP just pressing WASD

[Sphere]

Just use the "Revert Flight" button.

[eatham]

My reasoning would just be, “An abort tower doesn’t look as cool”

[alekseishuvalov]

I' surprised, that talking about "abort towers" your never mentioned Soyuz T-10/1. That time when abort tower actually saved lives.

[arun]

"pointy end up flamey end down" I want that on a shirt

[RockinRobbins]

You aren't the first to report on this issue, but you are the best, most balanced, most thoughtful treatment. Looking forward to details of the SpaceX anomaly. Don't do it fast, do it WELL!

[trippydrew]

Man am I on a massive space video binge. The past few days have really re-ignited my interest in space. thank you for playing a part in that bro!!

[devindorton]

One year later SpaceX just launched our first humans from the us in 9 years

[Nowhereman]

Some interesting history that you didn't cover here is that the Space Shuttle orbiters were originally supposed to have a LES of their own and that design was kept well up until when the vehicle was to go into production, but like other features it was dropped to save weight, complexity, and most importantly money. The system was referred to as the Abort Solid Rocket Motors or ASRM. It could be described as a pusher-type since it was comprised of twin rockets attached to the sides of the orbiter's aft fuselage and when fired would carry the orbiter away from a malfunctioning stack.

The ASRM's weight was initially considered acceptable since when the Shuttle reached a point where it was no longer usable, it could be fired off, the thrust boosting the stack and countering the dead weight, then jettisoned. So what's the big deal? Aside from cost there was another problem that kept rearing its ugly head; an abort scenario where the ASRM was used invoked heavy stresses on the orbiter airframe and so to keep the vehicle from breaking apart due to the aerodynamic load, the frame had to be beefed up structurally to the tune of a whopping 9 metric tons! In addition, this would not save the orbiter or its crew and payload in the advent of an exploding SSME, so its usefulness was limited to failures of the ET or SRBs.

Since NASA was under a great deal of pressure to make the Shuttle meet the DoD, CIA, and NRO's payload requirement of 65, 000 lbs (29 tons) to LEO, and with costs for the program rising, ASRM was deleted from the design.

Skip over two decades later and the design of the HL-20 lifting body that was the inspiration for SNC's Dream Chaser was also going to use a pusher type abort system. However this was a separate system not directly integrated into the craft and was a part of the cone-shaped launch vehicle adapter. The crewed variant of Dream Chaser, HL-20's successor, uses an integrated pusher system that also doubles as the orbital maneuvering system. Cargo Dream Chaser could in theory use this, but being stuck under a fairing makes its use impossible.

[handlebarfox]

4:20 *watching that thing spin and imagining the amount of vomit flying around the cabin*

[alexiscannon]

how am i just now realising the two different colored eyes

[venkataramanan]

I like the falcon heavy in the background

[colonelstriker]

11:30 now my life is complete. I now know how that anti ballistic missile steers with those plenty of holes on the side. I thought those are mini solid rockets stitched together

[crazed]

Watches a rocket video on YouTube:
“Abort capsules...liquid cooled abort ejection... feels like being hit by a semi truck for a continuous 15 seconds...”

Gf: “What the f### are you watching?!”

[filmgimix]

I think if space x played more KSP then they could get to mars..

[MrJonang]

Because, they can shut down a liquid fuel rocket.