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
New Launch Vehicle Details
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.
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 "worlds 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.
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.
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
(1) 200 km x 28.7 deg
(2) 200 km x 51.5 deg
COTS Demo Booster ("Athena III")
||6.0 t (1)
||2.5 Seg RSRM +
Castor 120 Stg 2
+ Castor 30 Stg 3 + OAM Stg 4
|ATK COTS Demo Booster ("Athena III")
||6.71 t (1)
||2.5 Seg Composite Case RSRM + Castor 120 Stg 2 + Castor 30 Stg 3 + OAM Stg 4
|ATK Smallsat Launcher ("Athena I")
||0.82 t (1)
||Castor 120 Stg 1 + Castor 30 Stg 2 + OAM Stg 3
2.5 Seg RSRM
2.5 Seg RSRM
Orbit Adjust Module
||3.9 m (est)
||26.35 m (est)
||9 m (est)
||31 t (est)
||1.3 t (est)
|Propellant Mass (tonnes)
||344 t (est)
|Total Mass (tonnes)
||375 t (est)
||2.5 Seg RSRM
||2.5 Seg RSRM
|820 t (est)
||820 t (est)
|838.96 t (avg)
||839 t (est)
||171.88 t (avg)
||26.39 t (avg)
|ISP (SL sec)
|ISP (Vac sec)
||275.9 s (avg, est)
||275.9 s (est)
||278.9 s (avg)
||294 s (avg, est)
|Burn Time (sec)
||113.2 s (est)
ATK Space Propulsion Products
Catalog, May 2008
Last Update: January 6, 2009