Space Launch Report:   ATK COTS DEMO LAUNCHER
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psatk1s.jpg (PlanetSpace)ATK's Proposed PlanetSpace Launcher (Updated 1/06/09)

On November 21, 2007, PlanetSpace, a Chicago-based "New Space" company, announced that it had teamed with aerospace giants Lockheed Martin and ATK to submit a proposal response for NASA's COTS (Commercial Orbital Transportation Services) program.  The proposal was triggered by NASA's October 18, 2007 decision to cancel Rocketplane-Kistler's original COTS contract, a move that freed up to $174 million for the Phase 1 Demonstration program.

COTS Phase 1 is program designed to culminate in demonstration, by private industry, of the ability to transport cargo and crew to the International Space Station. SpaceX and Rocketplane-Kistler won the original COTS contracts.

Planetspace's Chairman, Dr. Chirinjeev Kathuria, said that the proposal was innovative, low risk, and that it provided the added benefit of establishing a new low cost launch service for use by both NASA and commercial customers. He provided no details of the proposal beyond stating that it "leveraged heritage spacecraft, launch vehicle, and commercial business expertise".

The proposal team included PlanetSpace, BMO Capital Markets (“BMO”), Lockheed Martin Space Systems Company, who would develop a "Modular Cargo Carrier" (MCC), and ATK Launch Systems, who would develop a new launch vehicle. Space Florida, United Launch Alliance, Wyle Laboratories, Paragon Space, and MEHTA Engineering were also involved.

New Launch Vehicle Details Released

On January 21, 2008, ATK released some details of its proposed COTS launch vehicle to NASASpaceFlight, Florida Today, and several other space media services.  The reports indicated that the launch vehicle would have three solid motor primary stages topped by a monopropellant "trim" stage. 

The first stage would be based on ATK's Space Shuttle Reusable Solid Rocket Motor (RSRM).   It would use 2.5 motor segments, compared to the four normally used by each Space Shuttle booster.   The first stage would not be recoverable like the Shuttle boosters. 

The second stage would be an ATK Castor 120, a motor with a proven flight history that has been used with Athena I, Athena II, and Taurus launch vehicles. 

The third stage would use a new ATK "Castor 30" motor.     If it follows traditional motor naming conventions, Castor 30 should be loaded with about 30,000 lbs (13,600 kg) of propellant at launch.  ATK has been developing Castor 30 for a year or two.  Interestingly, Castor 30 appears to match the reported second stage requirements of Orbital Sciences Taurus II COTS launch vehicle proposal.

The launch vehicle would be topped by an Orbit Adjust Module (OAM) of the type previously flown on Lockheed Martin's Athena I and II launch vehicles. OAM was a pressure-fed monomethylhydrazine (MMH) propulsion system that provided on-orbit maneuvering and trim.  

The new launch vehicle would be able to lift about 6 metric tons (tonnes) to low earth orbit (LEO), using existing Shuttle SRB-style steel motor casings.  New composite first stage motor casings would improve LEO performance to 6.71 tonnes.  ATK said that the launch vehicle (presumably the composite case version) would be able to boost 2.793 tonnes to geosynchronous transfer orbit, 1.88 tonnes to a trans-lunar trajectory, and 1.357 tonnes toward Mars. 

The top three stages could fly as a small launch vehicle very similar to the former Lockheed Martin Athena 1.  

Overall, the announced launch vehicle parameters were roughly in line with the predictions provided on this page in early January, 2008, except that the proposed Castor 30 stage would likely weigh several tonnes less than predicted.  That attempt to "reverse engineer" the ATK COTS launcher is presented in the following paragraphs.

"Reverse Engineering" the ATK Booster (As originally Presented Here on January 2, 2008)

No details of the proposed booster were provided (on November 21, 2007) except for an artists rendering, making the following effort to "reverse engineer" the Planetspace/ATK launch vehicle proposal inherently flawed and, probably, foolhardy. It is not possible to know, for example, if the released image was an accurate portrayal or was designed to serve as "disinformation" to throw off other competitors who might bid for the COTS money. As a result, the following analysis should be treated as a very rough approximation of the truth at best.  There is a very good chance that the following is horribly off-base. 

Since ATK is the "world’s leading supplier of solid rocket motors" it stands to reason that the new launcher would use solid rocket motors. Since Space Florida is on the team, it also stands to reason that Space Launch Complex 46, located near the "tip" of Cape Canaveral, could host the launches. Road patterns in the image were consistent with roads near SLC 46, but the image also showed lightning protection towers that are not currently part of the launch site, which last hosted an Athena launch in 1999.

COTSs.jpg (9269 bytes)ATK builds the Castor 120 motors used by Athena and Taurus launch vehicles. SLC 46 was designed to handle Castor 120-class boosters, but the tantalizing press release image does not appear to show a launch vehicle with a Castor 120 first stage. Rather, it appears to show a launch vehicle with a first stage based on 3.71 meter diameter Space Shuttle SRB (solid rocket booster) segments topped by a 2.36 meter diameter Castor 120-like second stage and an unknown third stage. One interpretation of the drawing is that it shows two SRB segments, equivalent to one-half of a Shuttle SRB. Another interpretation is that it shows two-and-one-half SRB segments.  A third interpretation could be that it shows a new first stage not related to the SRB design.  

The original COTS announcement listed several capability requirements. These included the ability to lift a combined total of "up to" 16 tonnes of cargo per year to ISS using two to eight flights per year. Thus, the minimum launch vehicle/cargo carrier would need to be able to haul at least 2 tonnes of cargo per flight. A cargo carrier spacecraft with 2 tonnes of cargo would have to weigh at least 5.5 tonnes at liftoff, based on the examples of Europe's ATV, Japan's HTV, and Russia's Progress M. A launch vehicle would, as a result, have to be able to boost at least 5.5 tonnes to a low earth orbit in the ISS plane (51.6 degrees inclination), referred to hereafter as "LEO/ISS".

A launch vehicle consisting of a 2.5 segment SRB-type first stage, a Castor 120 second stage, an Orbus 21D third stage, and an Orion 50 fourth stage would be able to boost 5.5 tonnes to a 51.6 degree LEO, and 6.2 tonnes to a 28.5 deg LEO, from Cape Canaveral.

The Orbus 21D motor once used by Athena launch vehicles is no longer available. As a result, ATK would either have to initiate production of a similar motor or develop an all-new, more powerful motor. One possibility is a motor that would be the same diameter as Castor 120, but only 35% as long. It would weigh about 18.55 tonnes loaded and would produce more than 57 tonnes of thrust. Interestingly, such a motor would also appear to match the needs of the Orbital Sciences Taurus II second stage.   A 2.5 segment SRB-type first stage and Castor 120 second stage topped by such a third stage should be able to lift 5.5 tonnes to LEO/ISS.

Using only two SRB segments on the first stage would make it more difficult to reach the 5.5 tonne payload goal. At least four stages would be needed. Stage four could be an existing Orion 50 type, but the third stage would have to be something new, and would have to be even bigger than a 35% length Castor 120.  A 40% length Castor 120 could do the job, for example.

The rocket would stand somewhere in the 51 meter height range, including 10 meter long payload fairing, would weigh 380 to 450 tonnes at liftoff, and would produce as much as 977 tonnes (2.15 million pounds) of liftoff thrust.

A rocket of this type would need a taller service tower at SLC 46, and possibly a new flame trench as well. The existing service tower can only handle rockets that are up to 36 meters tall and 3 meters in diameter.

COTS Award

NASA awarded COTS funding to SpaceX and Orbital in early 2008.  On December 23, 2008, NASA awarded the $3.5 billion Commercial Resupply Services (CRS) contract to SpaceX and Orbital, again bypassing the PlanetSpace proposal.  Whether ATK's proposed booster would be developed without the COTS funding remains to be seen.  Meanwhile, it can be contemplated alongside other proposed medium launch vehicles like Orbital Sciences Taurus II and SpaceX Falcon 9.

- Ed Kyle

Vehicle Configurations (Estimated)

  LEO
Payload
(metric tons)
(1) 200 km x 28.7 deg
(2) 200 km x 51.5 deg
Geosynchronous Transfer Orbit Earth Escape (C3=0) Configuration LIftoff
Height
(meters)
Liftoff
Mass
(metric tons)
(no payoad)
ATK COTS Demo Booster ("Athena III") 6.0 t (1)
- - 2.5 Seg RSRM + Castor 120 Stg 2
+ Castor 30 Stg 3 + OAM Stg 4
~50 m ~455-465 t
ATK COTS Demo Booster ("Athena III") 6.71 t (1) 2.79 t 1.36 t 2.5 Seg Composite Case RSRM + Castor 120 Stg 2 + Castor 30 Stg 3 + OAM Stg 4 ~50 m ~435-445 t
ATK Smallsat Launcher ("Athena I") 0.82 t (1) - - Castor 120 Stg 1 + Castor 30 Stg 2 + OAM Stg 3 ~40 m ~70 t


Vehicle Components

Stage 1
2.5 Seg RSRM
Steel Case
Stage 1
2.5 Seg RSRM
Composite Case
Stage 2
(Castor 120)
Stage 3
(Castor 30)
Stage 4
Orbit Adjust Module
Payload
Fairing
Diameter (m) 3.71 m 3.71 m 2.36 m 2.34 m 2.3 m 3.9 m (est)
Length (m) 26.35 m 26.35 m (est) 10.7 m 3.5 m 1.0 m 9 m (est)
Empty Mass (tonnes) 49.08 t 31 t (est) 4.07 t 1.224 t 0.36 t 1.3 t (est)
Propellant Mass (tonnes) 344.21 t 344 t (est) 49.00 t 12.834 0.354 t -
Total Mass (tonnes) 393.29 t 375 t (est) 53.07 t 14.06 0.714 t -
Engine 2.5 Seg RSRM 2.5 Seg RSRM Castor 120 Castor 30 MR-107 -
Engine Mfgr ATK ATK ATK ATK Primex -
Fuel solid PBAN solid HTPB solid HTPB solid HTPB Hydrazine -
Oxidizer solid PBAN solid HTPB solid HTPB solid HTPB - -
Thrust
(SL tons)
820 t (est) 820 t (est) 163.27 t - - -
Thrust
(Vac tons)
838.96 t (avg) 839 t (est) 171.88 t (avg) 26.39 t (avg) 0.09 t -
ISP (SL sec) 237 s 237 s 229 s - - -
ISP (Vac sec) 275.9 s (avg, est) 275.9 s (est) 278.9 s (avg) 294 s (avg, est) 222 s -
Burn Time (sec) 113.2 s 113.2 s (est) 79.5 s 143 s 1,500 s -
No. Engines 1 1 1 1 4 -
Comments
- - TVC Nozzle TVC Nozzle Monopropellant,
Pressure Fed
-


References

http://www.planetspace.org
http://www.nasaspaceflight.com/content/?cid=5337
http://www.flightglobal.com/articles/2008/01/21/220950/picture-atk-releases-first-image-of-planetspace-cots-bid-launch-vehicle.html
ATK Space Propulsion Products Catalog, May 2008

Last Update:  January 6, 2009