Space Shuttle V2 Thought Experiment

[shynung]

Suppose that in the near-future, a space launch service agency/corporation wants to construct a high-capacity semi-(or fully)reusable space launch system, with the following design requirements:

-60 tons to LEO payload.

-Staging permitted.

-No more than 20% of hardware by mass is discarded in each mission. 80% must be recovered.

-Any discarded hardware must be of low value (spent SRBs, empty fuel tanks sans engine, fairings).

-Capable of precision landing. Either runways or landing pads are acceptable. Maximum reentry G-loads capped at 4G.

-Cargo bay large enough for 2 standard 40-foot intermodal containers.

-Crew optional. LES required, ejects only the crew cabin.

-Propellant primarily LH2/kerosene-LOX, other (hypergolic/exotic fuels, nuclear) propulsion systems acceptable above 100km.

-Price-per-kilogram must be comparable to currently-available launch vehicles.

-Post-landing maintenance costs must be cheaper than building costs for a single unit.

A single vehicle is expected to launch 4-5 mission per year (about one launch every 3 months), and to last at least 20 flights (4 year's worth of use).

How would such a vehicle look like? How would it fly? How would its typical mission proceed?

P.S. I request that we avoid discussing the economic consequences of such a vehicle operating, and focus our attention about the vehicle. Thank y

Edited May 12, 2015 by shynung

[Rakaydos]

wait, no LESS than 80% of the mass must be discarded? that looks like a typo.

[Kryten]

Falcon heavy would fill all of those requirements with crossfeed and a a slightly bigger upper stage.

[Captain Sierra]

-No less than 80% of hardware by mass is discarded in each mission.

You sure you don't mean 'more'? Dropping at minimum 80% of the launch vehicle results in a pretty poor payload fraction.

[shynung]

Whoops. Edited.

[Rakaydos]

Assuming you mean no more than 20% discarded... lets start with a falcon heavy-inspired base.

Liquid fuel boosters that return to launchpad, a center core that ejects the engines with an inflatable heatshield for midair recovery downrange, and a NERVA upper stage designed to be refueled and reused for orbital construction projects and interplanetary tugs. Payload pod is designed with propulsive landing as primary, with parachute backup.

[shynung]

Liquid fuel boosters that return to launchpad, a center core that ejects the engines with an inflatable heatshield for midair recovery downrange, and a NERVA upper stage designed to be refueled and reused for orbital construction projects and interplanetary tugs. Payload pod is designed with propulsive landing as primary, with parachute backup.

Adding to your idea, the inflatable heatshield could double as flotation devices, so that the ejected engine could simply splash down by parachute to be recovered by ship.

Though, it had to be shaped correctly, else it would turn turtle and dunk the engine into seawater, ruining it.

[Rakaydos]

Adding to your idea, the inflatable heatshield could double as flotation devices, so that the ejected engine could simply splash down by parachute to be recovered by ship.

Though, it had to be shaped correctly, else it would turn turtle and dunk the engine into seawater, ruining it.

Eh, perhap as a backup, but from what I'v read, even getting sea spray in the engine workings is an issue with reuse. (something that's likely to be an issue with reusing the falcon heavy's center core via barge) A midair recovery bypasses the issue entirely.

[Frozen_Heart]

Falcon heavy would fill all of those requirements with crossfeed and a a slightly bigger upper stage.

Not even close. Flying reusable will cut its max payload to about 20 tons. OP wants 60 tons.

Going to need something twice the size of the SLS...

Maybe a 27 raptor, tri core launch vehicle similar to the falcon heavy. Given current stats for the Raptor it would have just over 3 times the thrust of the Falcon Heavy, a much more powerful upper stage, and overall much higher ISP.

Each core has 9 Raptors the in the same layout as the Falcon 9 has Merlins. Upper stage uses a Raptor vacuum version

Could build the fairing to hinge open to release payload and then close again for upper stage re-entry.

Could possibly manage 60 tons fully reusable?

Edited May 12, 2015 by Frozen_Heart

[Rakaydos]

Not even close. Flying reusable will cut its max payload to about 20 tons. OP wants 60 tons.

Going to need something twice the size of the SLS...

Clearly, this calls for welding 3 Falcon Heavies together, broadside.

[Motokid600]

How about a launch escape system for the crew? Crew cabin would be a separate detachable entity like that of a drag race boat.

[Rakaydos]

How about a launch escape system for the crew? Crew cabin would be a separate detachable entity like that of a drag race boat.

for my FH inspired design, I lifted the Crew Dragon's abort mode. I assume it scales to the required 60 tons- if not, there might be a technical issue.

[shynung]

How about a launch escape system for the crew? Crew cabin would be a separate detachable entity like that of a drag race boat.

Right. Added to OP.

for my FH inspired design, I lifted the Crew Dragon's abort mode. I assume it scales to the required 60 tons- if not, there might be a technical issue.

Assuming the cargo is placed outside the Crew Dragon pod, the current SuperDraco engines should be enough.

Could build the fairing to hinge open to release payload and then close again for upper stage re-entry.

Farings are just dumb plates. Discarding them is OK.

The way I see it, the upper stage engines could be placed ahead of the payload, in a pulling configuration. Think Dragon V2 with fuel tank under the crew pod. Payload is attached to the bottom of the fuel tank, and the Dragon capsule above it. When the payload has been deployed and time to reentry, empty fuel tank is discarded, Dragon V2 reenters, then lands propulsively via internal fuel tanks.

Edited May 12, 2015 by shynung

[Kryten]

Energiya II/Uragan would supposedly have capability in this range, but costs comparable to current systems are doubtful without high flight rates.

[adsii1970]

As much as I love the space shuttle, I would have to say that given the parameters in this scenario, a reusable shuttle will not be a realistic option. With the weight of the cargo, I think that Dragon or SpaceX will eventually corner the market. Shuttles simply are not cost effective even if only 20% of the total mass was expendable. A VTOL SSTO shuttle would only work ideally as a passenger ferry or for lighter cargo loads at our current level of technology. And even that would be a stretch to say the least.

I remember reading an article a while back ago about the Japanese playing around with gravity and magnetic fields. Now, if this technology does pan out (if you think of Star Trek's 1980s movie, ST: The Motion Picture) and we see common applications such as load bearing carts that use an anti-gravity magnetic field instead of wheels, the technology may be expanded to include a sort of magnetic drive that could propel spacecraft from the surface into LEO. This would allow for a more feasible SSTO shuttle that could possibly bear the cargo weight as proposed in this scenario AND be under the 20% expendable requirement.

[shynung]

It doesn't have to be shaped like the STS Shuttle; the booster can return to Earth separately, a la Falcon 9 Reusable. The crew pod can use Dragon V2 capsules, the cargo can use disposable fairings and mounting struts. All it has to do is to return 80% of its non-propellant mass in a reusable form.

I'm thinking an Energiya-based rocket with propulsive-landing/folding-winged gliding side boosters, a center core that ejects the center engine for retrieval, side-mounted cargo rack with a disposable fairing, and a Dragon V2-style crew pod bolted to the top of the cargo rack, with a disposable inline external tank covering the heat shield between the pod and the rack. The pod's landing/LES engine acts as OMS with fuel fed from external tank. After cargo is deployed/detached, the pod does a retroburn using fuel left in the tank, then discards the tank, exposing the heat shield. At final approach, pod engine fires again using internal fuel for propulsive landing.

Edited May 12, 2015 by shynung

[Rakaydos]

Right. Added to OP.

Assuming the cargo is placed outside the Crew Dragon pod, the current SuperDraco engines should be enough.

Farings are just dumb plates. Discarding them is OK.

The way I see it, the upper stage engines could be placed ahead of the payload, in a pulling configuration. Think Dragon V2 with fuel tank under the crew pod. Payload is attached to the bottom of the fuel tank, and the Dragon capsule above it. When the payload has been deployed and time to reentry, empty fuel tank is discarded, Dragon V2 reenters, then lands propulsively via internal fuel tanks.

So to recap:

Liquid fuel boosters with fuel crossfeed, return to launch pad vertically

Center core with engines intended to survive reetry for reuse. (mid-air retrieval)

Upper Stage is a high efficency dual mode NERVA specifically designed to be repurposed as a reactor or transfer engine, on a different vehical.

Payload return capsule (if any) uses parachute assisted propulsive landing

Abort mode on the payload pod uses the propulsive landing engines to break free of the fairing and escape to saftey.

[magnemoe]

As much as I love the space shuttle, I would have to say that given the parameters in this scenario, a reusable shuttle will not be a realistic option. With the weight of the cargo, I think that Dragon or SpaceX will eventually corner the market. Shuttles simply are not cost effective even if only 20% of the total mass was expendable. A VTOL SSTO shuttle would only work ideally as a passenger ferry or for lighter cargo loads at our current level of technology. And even that would be a stretch to say the least.

I remember reading an article a while back ago about the Japanese playing around with gravity and magnetic fields. Now, if this technology does pan out (if you think of Star Trek's 1980s movie, ST: The Motion Picture) and we see common applications such as load bearing carts that use an anti-gravity magnetic field instead of wheels, the technology may be expanded to include a sort of magnetic drive that could propel spacecraft from the surface into LEO. This would allow for a more feasible SSTO shuttle that could possibly bear the cargo weight as proposed in this scenario AND be under the 20% expendable requirement.

I agree, an small shuttle should work well, imagine an miniature shuttle, say 1/3-1/2 of the original It looks much like the shuttle except its more lifting body, This is upper stage on an Falcon 9 style reusable first stage, Like the shuttle it has an drop tank but this is smaller as its only used in upper stage, engines is also smaller. Cargo bay is small but it has an arm so it can do repair and assembly, Cargo bay is modular, arm+ eva facility for this, else its pressurized cargo or you can add an pressurized cargo module if needed.

You can use the lower stage with an discardable upper stage, posible future version might be an shuttle with only an larger unpressurized hold.

[shynung]

So to recap:

Liquid fuel boosters with fuel crossfeed, return to launch pad vertically

Center core with engines intended to survive reetry for reuse. (mid-air retrieval)

Upper Stage is a high efficency dual mode NERVA specifically designed to be repurposed as a reactor or transfer engine, on a different vehical.

Payload return capsule (if any) uses parachute assisted propulsive landing

Abort mode on the payload pod uses the propulsive landing engines to break free of the fairing and escape to safety.

That, or:

-Liquid fuel boosters with crossfeed capability, glides back to runway via folding wing/parafoils

-Nuclear thermal rocket upper stage, either designed for reuse as orbital tug, or to eject the engine the same way as the center core engine

-Only crew pod returns, landing via parachute assisted propulsive landing, OR Payload capsule and crew pod returns separately, both by parachute-assisted propulsive landing.

Edited May 12, 2015 by shynung

[Frozen_Heart]

Farings are just dumb plates. Discarding them is OK.

I just saw it said cargo bay in the OP so I assumed that bit had to come back. Discarding the fairing makes more sense considering they're so cheap.

[shynung]

I just saw it said cargo bay in the OP so I assumed that bit had to come back. Discarding the fairing makes more sense considering they're so cheap.

A cargo bay would something be like the old Shuttle's bay, or Skylon's. If the vehicle simply stacks the payload like a traditional rocket, only returning the crew capsule (think Saturn V), then the fairings are unimportant.

Though, if using a proper cargo bay on a spaceplane-esque vehicle, the design must take care of fitting 2 shipping containers inside a Mach 5+ airframe. A typical rocket can simply stack the boxes on top of the booster, and cover it with cheap fairings.

Edited May 12, 2015 by shynung

[meve12]

Eh, perhap as a backup, but from what I'v read, even getting sea spray in the engine workings is an issue with reuse. (something that's likely to be an issue with reusing the falcon heavy's center core via barge) A midair recovery bypasses the issue entirely.

You could have a casing around the engine that stays with it when it drops, with fuel lines running through valves set in the baseplate. You close the valves when you detach the engines so water doesn't leak in, and the casing combined with an inflatable heat-shield/raft would minimize sea spray.

EDIT: Or just stick delta wings on the center stage and glide it around the world back to home.

Edited May 13, 2015 by meve12

[shynung]

I agree, an small shuttle should work well, imagine an miniature shuttle, say 1/3-1/2 of the original It looks much like the shuttle except its more lifting body, This is upper stage on an Falcon 9 style reusable first stage, Like the shuttle it has an drop tank but this is smaller as its only used in upper stage, engines is also smaller. Cargo bay is small but it has an arm so it can do repair and assembly, Cargo bay is modular, arm+ eva facility for this, else its pressurized cargo or you can add an pressurized cargo module if needed.

You can use the lower stage with an discardable upper stage, posible future version might be an shuttle with only an larger unpressurized hold.

The original full-sized Space Shuttle carried only 24 tons to LEO. There's no way a miniature version could carry 60 tons in an internal cargo bay like the original.

[Rakaydos]

You could have a casing around the engine that stays with it when it drops, with fuel lines running through valves set in the baseplate. You close the valves when you detach the engines so water doesn't leak in, and the casing combined with an inflatable heat-shield/raft would minimize sea spray.

EDIT: Or just stick delta wings on the center stage and glide it around the world back to home.

...or just catch it before it reaches the water. Seriously, this is a plan sponsored by ula of all people- its easy, simple, and conservitive, requiring very little engineering effort.

SpaceX's plan works better for the boosters, getting 100% recovsry, but core stage recovrry with spacex cuts deep into mass to orbit. The ULA plan recovers 90% of the costs without the mass penalty for the core stage- or the extra mass of wings for yhe booster and horizontal bracing to land on its s ide.

[billbobjebkirk]

For something like the falcon heavy, you could add reusability to a rocket the size of the Saturn M03 from Eyes Turned Skywards:

EDIT: Although, I do have to point out that 60 tonnes to orbit is a very odd size, as no rocket has ever been built to fit the 35-70 tonnes to orbit size range.

Edited May 13, 2015 by billbobjebkirk