Proposal: low cost, reusable version of the Ariane 6.

[Exoscientist]

ESA can get a low cost, reusable version of the Ariane 6 just by adding a second Vulcain to the Ariane 5.

Moveover, without needing the solid side boosters, this can be used to finally give Europe an independent manned spaceflight capability.

Multi-Vulcain Ariane 6.

https://exoscientist.blogspot.com/2018/02/multi-vulcain-ariane-6.html

  Bob Clark

[YNM]

I think they'd still need an experimental case with the boostback and landing though.

 

And being an agency under even more scrutiny I wonder whether they'd catch up at all. I say they will only loft their own payload and occasional others (F9 lacks fairing size).

[Canopus]

The Booster aren‘t the reason that Europe doesn‘t have a manned spacecraft. Infact the Ariane 5 was originally meant to launch people onboard the Hermes. Simple fact is, as of right now, there simply is no reason for an independant Human Spaceflight capability. I‘m also sceptical of the rest of the idea. Everytime someone says something is easy or low cost, it turns out to be hard. Thats just a fact when it comes to Spaceflight.

[MajorTomtom]

I don't see how a 2 vulcain variant of Ariane would be more reusable than Ariane 5 or 6. Moreover, the european space program is concerned about which country builds what, and it turns out that the italians are good at solid rocket, and the french need to keep fresh on the technology because of ICBM research.

[Starman4308]

6 hours ago, MajorTomtom said:

I don't see how a 2 vulcain variant of Ariane would be more reusable than Ariane 5 or 6. Moreover, the european space program is concerned about which country builds what, and it turns out that the italians are good at solid rocket, and the french need to keep fresh on the technology because of ICBM research.

Looks like the primary advantage of going to a 2-engine Ariane 5 is that it doesn't need strapon SRBs to launch, and nobody's seriously tried to reuse SRBs since the Space Shuttle.

Regardless, one thing I noticed about this: there is no discussion of all the other factors necessary for reusability:

Deep-throttleability of engines.

That deep-throttleability isn't enough: the Falcon 9, for example, lands on just one engine heavily throttled down. Falcon 9 can shut off 8/9 engines, this 2-Vulcain Ariane can shut off 1/2 engines, assuming it can gimbal enough to compensate for off-center thrust.

Engine restart while flying tail-first through the atmosphere.

Recovery equipment such as aerodynamic control surfaces and landing legs.

 

The only "advance" is that the nation that makes the Vulcain engine gets more money at the expense of the nation that makes the SRBs. To get a reusable booster, ESA/Arianespace are probably going to need a clean-sheet design.

Edited February 28, 2018 by Starman4308

[PB666]

6 minutes ago, Starman4308 said:

Looks like the primary advantage of going to a 2-engine Ariane 5 is that it doesn't need strapon SRBs to launch, and nobody's seriously tried to reuse SRBs since the Space Shuttle.

Regardless, one thing I noticed about this: there is no discussion of all the other factors necessary for reusability:

Deep-throttleability of engines.

That deep-throttleability isn't enough: the Falcon 9, for example, lands on just one engine heavily throttled down. Falcon 9 can shut off 8/9 engines, this 2-Vulcain Ariane can shut off 1/2 engines, assuming it can gimbal enough to compensate for off-center thrust.

Engine restart while flying tail-first through the atmosphere.

Recovery equipment such as aerodynamic control surfaces and landing legs.

 

The only "advance" is that the nation that makes the Vulcain engine gets more money at the expense of the nation that makes the SRBs. To get a reusable booster, ESA/Arianespace are probably going to need a clean-sheet design.

Falcon final burn begins with 3 engines, if I am not mistaken.

[Gaarst]

Sticking a second engine under an Ariane 5 to somehow make it reusable is a terrible idea. Ariane 6 is already planned to be a low-cost rocket and its Vulcain 2.1 is a much simplified version of Ariane 5's Vulcain 2, using the latter would not be the most cost-efficient idea; Vulcain is also not designed to be reused or even reignited (I don't even think it can significantly throttle).

However, there's still the Adeline thing in the works which consists of recovering and reusing the most expensive components of Ariane 6's first stage (basically everything but the fuel tank) by flying it back to the launch site. AFAIK it hasn't been cancelled yet.

Edited February 28, 2018 by Gaarst

[Starman4308]

6 minutes ago, PB666 said:

Falcon final burn begins with 3 engines, if I am not mistaken.

It depends on the landing.

0-1-0 is typically used when there's plenty of margin.

0-1-3-1-0 is used for slimmer margins.

0-1-3-0 has been tested for water landings, but hasn't been demonstrated yet for recovery.

As I understand, though, even on 1 engine throttled all the way down, it has too much thrust to hover: they stick it first try, or they don't land at all.

[sevenperforce]

54 minutes ago, Starman4308 said:

It depends on the landing.

0-1-0 is typically used when there's plenty of margin.

0-1-3-1-0 is used for slimmer margins.

0-1-3-0 has been tested for water landings, but hasn't been demonstrated yet for recovery.

As I understand, though, even on 1 engine throttled all the way down, it has too much thrust to hover: they stick it first try, or they don't land at all.

Correct. 

[ment18]

It is possible to land boosters at extremely high accelerations, just reduces margin for error greatly.  The changes suggested are all extremely large, complicated, and expensive.  You can't just stick a second engine on the bottom of a vehicle, it greatly changes all the forces going through the vehicle and the entire structure of the bottom of the vehicle such as plumbing.  Secondly, the rocket would loose half its payload, meaning you can only launch 1 sat at a time, halving the cost target you need to reach.  Restarting engines is extremely far from trivial.  Until a few years ago, supersonic propulsion was a big deal, and SpaceX is a private company so it doesn't share stuff.  SRBs have nothing to do with man rating (Atlas V, Shuttle).  SpaceX said it cost them about a billion to develop retropulsive re-usability, so it would probably 2-5 billion for Europe, which is not remotely acceptable for them.  Also no throttling means landing is basically impossible.  Can't correct for anything.

[Exoscientist]

 ESA may have no choice in the matter. SpaceX is progressingly rapidly to reusability and to reduced costs. The current version of the Ariane 6 does not allow reusability. By its scheduled time of full operation in 2023, it may already be obsolete.

  Bob Clark

[Starman4308]

28 minutes ago, Exoscientist said:

 ESA may have no choice in the matter. SpaceX is progressingly rapidly to reusability and to reduced costs. The current version of the Ariane 6 does not allow reusability. By its scheduled time of full operation in 2023, it may already be obsolete.

  Bob Clark

Unfortunately for the Ariane 6, it's not exactly a great platform to design reusability around. Propulsive retro-fire landing is right out due to the inability to throttle down to anywhere near enough to reasonably consider landing a near-empty booster. Adeline might work, but that would entail a pretty significant redesign of the Ariane 6 first stage.