Challenge Create a SSTO from already existing stages and engines.

[RGClark]

It is my contention that SSTO's are possible now and have been for decades. See the discussion in this thread: An SSTO as "God and Robert Heinlein intended" . This is no mere theoretical fact. It is also my contention that if SSTO's are instituted then the cost to orbit can be cut to a few hundreds of dollars per kilo.
In the posts to that thread, I gave estimated delta-V calculations based on the rocket equation for how mix and matching various existing components or components we had in the past you could get a SSTO. However, I would like to get a more accurate and convincing demonstration of this.
Anyone want to try to do an orbiter simulation of how you can get a SSTO using highly weight optimized stages with the engines swapped out to use the highest average Isp, sea level to vacuum, engines available now?
I'm especially interested in what average Isp you can get for your trajectory, and what is the minimum delta-V you need both for kerosene fueled and hydrogen fueled SSTO's. For instance in that thread on SSTO's I used an estimate that the trajectory-averaged Isp was 2/3rd's of the way from the sea level value to the vacuum value. I'm fairly sure though that this underestimates the average Isp you can get with a good trajectory. For instance this estimates the average Isp of the SSME's as 425 s. However, I've seen an estimate by a NASA official that it was in the range of 437 s. And I've confirmed this myself by numerically integrating the SSME thrust values according to altitude calculated from the altitudes values given on this page:

typical Shuttle / ISS Mission launch track.
http://www.orbiter-forum.com/showthread.php?p=33293&postcount=8

and getting a value in the upper 430's for the average Isp.


Bob Clark

 

[Artlav]

There are several SSTO-capable rocket stages out here. The problem is that in this case there will be negligible payload capacity.
And, to have any purpose at all it all have to be reuseable, needing special-built thing anyway.

 

[T.Neo]

I came across a forum thread somewhere on the internet where a guy suggested a 1.5 stager based on the STS ET and the SSME/RS-68. It was silly, but interesting nontheless.

He even talked about a whole family of launchers based on clustered vehicles.

Various stages could potentially be used in a sort of SSTO arrangement, but likely with little useful payload. A launch vehicles in general get lighter and lighter, though...

 

[RGClark]

There are several SSTO-capable rocket stages out here. The problem is that in this case there will be negligible payload capacity.
And, to have any purpose at all it all have to be reuseable, needing special-built thing anyway.

That's my point. I don't believe that to be the case. My calculation showed you could get a good payload by replacing the low efficiency engines originally placed on some prior stages with high efficiency engines available now.
The payload is so good they would be economical as expendables. But there is sufficient payload to even add reentry/landing systems and still get good payload.

Bob Clark

 

[T.Neo]

But there is sufficient payload to even add reentry/landing systems and still get good payload.

I can't help but be skeptical of this statement...

 

[Urwumpe]

I can't help but be skeptical of this statement...

I can't help but be skeptical that the OP knows that rocket stages are integral parts of their respective launch vehicles and can't be turned into an SSTO just by saying so.

You can take the engines, but then most internet resources don't go into the needed engineering details to really make reliable estimates, when you are talking about less than 1% payload mass fraction.

 

[n0mad23]

Would using a launch platform like the White Knight and Space Ship One (Scaled Composites) still be considered a SSTO, or is this a TSTO?

I've wondered if a platform like this but maybe using Siamese Twin C-5Cs to carry the rocket to launch might be the solution.

 

[RGClark]

Would using a launch platform like the White Knight and Space Ship One (Scaled Composites) still be considered a SSTO, or is this a TSTO?

I've wondered if a platform like this but maybe using Siamese Twin C-5Cs to carry the rocket to launch might be the solution.

That is only suborbital, but an analogous orbital system would be considered TSTO.
However, if a orbit capable vehicle got a sled boost on the ground I would consider that SSTO.


Bob Clark

 

[hribek]

Is sled boost considered to be an existing stage or engine?

 

[APDAF]

No.

 

[T.Neo]

To be honest I really don't see the advantage of a sled boost, considering the velocity gain vs. extra mass/complexity/cost.

 

[RisingFury]

My calculation showed...

Show us the calculations...

 

[RGClark]

Is sled boost considered to be an existing stage or engine?

I myself would consider an orbital vehicle that used sled launch assist still to be SSTO if it used only one stage after the ground launch to reach orbit.
Here's one report that considers it:

A STUDY OF ARTS: A DUAL-FUEL REUSABLE LAUNCH VEHICLE WITH
LAUNCH ASSIST.
Jon Wallace, John Olds, A.C. Charania,
SpaceWorks Engineering, Inc. (SEI)
Gordon Woodcock,
Gray Research
39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
20-23 July, 2003, Huntsville, Alabama.
ABSTRACT
An independent assessment of the Advanced Reusable
Transportation System (ARTS) has been conducted.
The ARTS concept is an all-rocket, fully reusable
launch vehicle utilizing electromagnetic launch assist.
ARTS is fitted with a dual-fuel main propulsion system
utilizing flight proven Space Shuttle Main Engines and
RD-180s. Nominally, the vehicle is intended to operate
without a crew using autonomous guidance and control.
Conceptual analysis shows that the vehicle could boost
a payload of 48,140 lbs to a 110 nmi circular orbit in its
baseline configuration. The DDT&E cost of such a
system is estimated to be $8.8B (FY2003) using
existing liquid rocket engines, while the total cost to the
first vehicle is $11B...
http://www.sei.aero/eng/papers/uploads/archive/AIAA-2003-5269.pdf


Bob Clark

---------- Post added at 03:31 PM ---------- Previous post was at 03:24 PM ----------

Show us the calculations...

It's explained here: An SSTO as "God and Robert Heinlein intended"
Note it requires you to remove the low efficiency engines that came with the high mass ratio stages and replace them with NK-33 engines.


Bob Clark