Comments on: Russia to consider building reusable stages for Angara

By: Patrick Underwood

Patrick Underwood — Thu, 02 Jul 2020 16:32:15 +0000

Back in the Soviet day, I believe the Energia side boosters (which became Zenit) were designed to be recovered by parachute. Each booster had two large fairings on the side for the chutes. Don’t know if this capability was actually used on either of the two launches.

Doesn’t invalidate the argument about the Russian Federation’s space program though.

Russia had its chance. Sadly, you can rely on them to choose the wrong path, every.single.time.

By: john hare

john hare — Wed, 01 Jul 2020 23:29:41 +0000

Deep throttling is less critical with the hoverslam technique that SpaceX has pioneered.

By: Jay

Jay — Wed, 01 Jul 2020 21:15:06 +0000

David,
The RD-191 can only be throttled down to 30%. A redesign there. Also to make them reusable would need changes. The predecessor engine RD-171 was claimed to be reusable for the Zenit rocket.

I am willing to bet the tanks in the Angara-A5 are not the aluminum alloy that the F9 uses to save weight. Another redesign. The F9 is around 200,000 kg lighter than the Angara-A5.

You are correct, they would have to start from scratch.

By: David

David — Wed, 01 Jul 2020 19:45:21 +0000

I can’t see the Angara boosters capable of doing a powered descent and landing similar to F9, while the RD-191 is certainly throttleable, it’s not going to get down to the 10% or so of nominal thrust that would be necessary for a controlled landing of a nearly empty booster. And I believe they stage at a higher altitude/velocity than F9 does, which means dealing with more re-entry heat, etc. People forget how many fundamental design choices in the F9 booster were based on the reusability concept. Taking a booster that wasn’t designed with those considerations in mind and trying to alter the design is probably a much higher hurdle than starting from scratch.

By: Ray Van Dune

Ray Van Dune — Wed, 01 Jul 2020 18:35:17 +0000

V-man poses excellent questions! My thoughts / guesses FWIW are that:
1. To get to a reusability level “R7” – “Recover, rinse, retract, re-inspect, re-erect, re-fuel, re-launch” – you DO need a clean sheet of paper! (Or you will eventually wish you had used one!)
2. The first R, recover, is a prerequisite, and gets you some or even much of your physical investment back, but you are still going to spend a bundle of time/$$ doing the rest of the R’s, thus the clean sheet.
3. All this assumes payload integration occurs out-of-cycle, and bolting on a pre-integrated upper stage is simply part of re-erect, which is probably dreaming!

By: Jay

Jay — Wed, 01 Jul 2020 18:01:14 +0000

V-Man,
Yes, the RD-191 engines can be throttled. I do not know if it could be restarted.

By: V-Man

V-Man — Wed, 01 Jul 2020 16:33:07 +0000

Are the Angara’s current engines capable of throttling/restarting? Could it be as “easy” (ah!) as adding landing legs, control surfaces and new flight software?

(Probably not, but does a reusable rocket need a clean-sheet design?)