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-   -   STUDY SUMMARY: A Low Cost Modular Launch Vehicle for the Future (http://www.oldrocketforum.com/showthread.php?t=16483)

luke strawwalker 02-16-2017 02:59 PM

STUDY SUMMARY: A Low Cost Modular Launch Vehicle for the Future
 
1 Attachment(s)
Here's an interesting study from the University of Washington at Seattle, from June of 1991. It's a proposal to build a rocket for the comsat payload market, to compete against Ariane. The rocket was designed to be an SSTO, single stage to orbit, and to use a jettisonable reentry module housing the engine and avionics which would reenter and be recovered for reuse after paragliding down into an ocean splashdown. It was to be fueled with liquid hydrogen and oxygen, and was to use a reusable Dual Mixture Ratio Engine (DMRE) being studied at the time by Pratt and Whitney. This engine would have used a 12:1 mixture ratio for high thrust at liftoff, followed by extending a retractable nozzle extension in flight after liftoff, then after a bit longer switching to a lower thrust 6:1 ratio to reduce thrust and increase the ISP, to keep gee forces below 4 gees for payload requirements.

The entire rocket would enter orbit, separate the payload, and then the rocket's maneuvering system would reposition the rocket tail first for retrofire. Then the maneuvering thrusters would turn 180 degrees to point the tank forward in the direction of flight, then the rocket package would jettison the tank by blowing explosive bolts, separating the two modules via springs... a timer would then ignite a pair of solid rocket motors designed to push the tank away and spin it for stability, so that it would reenter a safe distance away from the rocket motor recovery unit (ERU). The tank would burn up and break up during reentry and crash into the ocean and sink; the engine package would be recovered for reuse by refurbishing it and remounting it on a new tank.

The rocket was unusual in that the design, in addition to being SSTO, was also to be used in a two stage configuration for launching satellites to geosynchronous Earth orbit by using a Centaur as the upper stage. The SSTO stage would fly suborbitally in that mission and land a couple thousand miles east of the Cape in that scenario.

The rocket was also unusual in that it was to be capable of anything from 10,000 lbs to LEO up to over 100,000 lbs (similar to Saturn V) by clustering the single engine first stages together into anything from a pair up to seven cores bolted together. The multiple core variants also were SSTO and designed to perform retrofire and then jettison the engine recovery units (ERU's) separately before solid rocket motors spun up and moved the tank assembly out ahead of the ERU's for reentry.

It was an interesting concept called "Antares" (no relation to the current Antares launch vehicle operated by Orbital Sciences Corporation). While the SSTO aspects are rather dubious IMHO, it was still a rather interesting proposal that would make an interesting rocket or group of rockets. In a scale competition, it could even get "mission points" by jettisoning the motor pods (ERU's) to recover under their own parachutes (or better yet parafoils) while the "tanks" could drop back to the ground under a streamer.

There's also a number of slides that could be of interest to rocketeers, about various nose cone and drag aspects among other things.

So, here's the summary and the plethora of diagrams and tables that accompanied the study itself. Enjoy!

OL J R

luke strawwalker 02-16-2017 03:04 PM

10 Attachment(s)
1. payload capabilities of various early 90's launch vehicles...

2. basic Antares layout...

3. Antares modular configurations...

4. big Antares modular configurations...

5. two stage Antares for geosynchronous launches...

6. DMRE parameters...

7. optimized baseline performance...

8. Centaur vehicle specs...

9. optimized geosynchronous orbit performance...

10. LEO mission profile...

luke strawwalker 02-16-2017 03:09 PM

10 Attachment(s)
1. LEO mission diagram...

2. GEO mission profile...

3. LEO to GEO mission profile... (Hohmann transfer).

4. effect of propellant mass on LEO payload (the Ares V guys should have read this one!)

5. effect of Centaur propellant mass and burn time on GEO payload...

6. velocities...

7. velocity diagram for plane change maneuvers...

8. optimization of incremental plane change maneuvers...

9. overall characteristics of the dual mixture ratio engine...

10. Rocketdyne XLR-132 and Marquardt thruster specs...

luke strawwalker 02-16-2017 03:13 PM

10 Attachment(s)
1. schematic cutaway of the engine return module (ERU).

2. ERU in GEO configuration...

3. ERU heat shield top view...

4. ERU bottom (nozzle) side view...

5. Antares 2 propulsion diagram arrangement...

6. Antares 3 diagram...

7. Antares 7 diagram...

8. solid rocket motor mounting...

9. Antares 3 SRM mounting diagram...

10. Antares 7 sequential separation...

luke strawwalker 02-16-2017 03:16 PM

10 Attachment(s)
1. PODS thrust frame...

2. ERU framing...

3. separation system side view...

4. ERU heat shield diagram...

5. ERU descent profile...

6. Antares propellant tank layout...

7. Antares propellant tank compared to shuttle ET...

8. common wall bulkhead...

9. Antares skin stringers and reinforcement rings...

10. Antares propellant lines...

luke strawwalker 02-16-2017 03:21 PM

10 Attachment(s)
1. honeycomb sandwich construction...

2. schematic of Antares propellant tank...

3. ERU/tank connections...

4. ERU main tank connections exploded view...

5. support post assembly...

6. GEO mission Centaur upper view...

7. ISA forward ring...

8. Antares payload envelope...

9. variation of drag coefficient with Mach number of a cone...

10. drag coefficient of conical sections...

luke strawwalker 02-16-2017 03:25 PM

10 Attachment(s)
1. off conical nose cone shapes...

2. combined drag effects of Antares...

3. Antares I payload fairing...

4. nose cone pressure distribution...

5. payload fairing for Centaur...

6. modular configuration for Antares...

7. Antares 7 payload fairing...

8. upper fairings for Antares 3...

9. upper fairings for Antares 7...

10. LEO mission configuration capabilities...

luke strawwalker 02-16-2017 03:29 PM

10 Attachment(s)
1. engine out capability...

2. engine out capability when dropping the failed engine...

3. hardpoint locations for Antares 3.

4. plan view of alternative Antares configurations...

5. double configuration propellant distribution system (cross-feed propellant).

6. propellant line locations for various configurations...

7. Antares 7 transporter...

8. ground ops for Antares 1.

9. ground ops for Antares 7.

10. comparison of reusable engine alternatives...

luke strawwalker 02-16-2017 03:31 PM

3 Attachment(s)
1. Antares LEO mission using various engines...

2. staged combustion engine propellant flow...

3. gas generator engine propellant flow...

Enjoy! OL J R :)


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