Presented by Walter Goedecke
April 24, 2007
Reason for Project Demise
The X-33 project was part of the NASA
Reusable Launch Vehicle (RLV) program
initiated after the 1986 Challenger
In January 1993, NASA, under
Administrator Dan Goldin, ordered a
series of internal studies, including the
Space Transport System
The second generation RLV was to
replace the space shuttle.
A projected order of magnitude operational
cost reduction compared to the current space
shuttle operations was foreseen.
– This was to lower the $10k/lb payload launch cost.
Some NASA projects to advance the single-
stage-to-orbit (SSTO) program were:
– DCX – a SSTO initiated by McDonnell Douglas
– X-34 – the parent project of the X-33
Unlike NASA, the Dept. of Defense took the
path of developing a line of “evolved
expendable launch vehicles” (EELV). 4
This dual use RLV was to satisfy both
the commercial launch market and
RLV development, however, also
required industry funding, since NASA
couldn’t fund this by itself.
The X-34 project was co-managed by Orbital
Sciences and Rockwell International.
The prototype of the X-34 was the one half
scale sized X-33, a sub-orbital pilotless
spacecraft to demonstrate proof of concept of
a totally reusable single stage vehicle
This vehicle was projected to cost $7 billion,
using both public (NASA) and private
Phase I, the design phase, was
awarded in Spring of 1995 to three
industry groups to design the vehicle
The groups and designs were:
– Lockheed Martin – a wingless delta shaped
– McDonnell Douglas & Boeing – a version of
– Rockwell – a space shuttle derived design
Comparison of the Lockheed Martin, McDonnell
Douglas & Boeing, and the Rockwell Designs
NASA choosing among industry designs
rather than designing in-house is a new
The award went to Lockheed Martin,
proposing their VentureStar vehicle, on July
Phase II of the X-33 project commenced -
NASA contributed $900 M and LM $200 M.
Later, under Phase III, LM would build the
VentureStar, using knowledge gained from
the X-33 prototype.
Comparison of the X-33, the VentureStar,
and the Space Shuttle
67 ft in length and 77 ft wide
Only an internal fuel tank constructed of honeycomb composite
walls and internal structures.
– Light enough in order for the craft to demonstrate necessary technologies for
single-stage-to-orbit (LEO) operations.
– Therefore more reliable and safer space launch vehicle.
Metallic thermal protection systems
Composite cryogenic fuel tanks for liquid hydrogen and ligquid
An aerospike engine
Autonomous flight control
– This was to be an unmanned proto-spacecraft
Lifting body aerodynamics.
The gross lift-off weight is 273,000 lbs
– The gross lift-off weight of the shuttle is 4,500,00 lbs
The Lockheed Martin X-33
Additional X-33 Pluses
The unmanned craft would have been launched
vertically, from a specially designed facility, and
have landed horizontally on a runway at the end
of its mission.
Rapid flight turn-around times through
– Unlike the Space Shuttle’s $500 M cost and lengthy
turn-around time for each flight.
VentureStar on the Launchpad
VentureStar in Orbit
The parent X-34 program, however faltered,
as joint government and industry co-
management and co-funding was
The X-33 program continued, with industry
eager to initiate Phase II.
Phase III, however, scared off private
industry, since this required 100% industry
funding and operation for a full-scale vehicle.
– LM could not finish the project with their own
– LM said in 1999 that the project would not attract
investors, and additional government backing was
Although 40% of the X-33 had been completed
and the launch facility at Edwards Air force
Base was 100% completed, problems occurred.
Rocketdyne decided to use a heavy copper alloy
(Narloy-Z) on the Linear Aerospike engines
were on target, causing center of gravity to
move aft wards.
– This caused consequent redesigns, such as the take-
Engineers and designers thought that the pressurized
composite liquid hydrogen (LH2) tanks with hollow
honeycomb walls would not work
Alliant Techsystems built the LH2 tank,but lacked
experience with composite tanks
The first tank had de-bonded and was sent back
Air would enter the honeycomb of the second tank
and liquefy, and thus failed
Although engineers thought that filling the
honeycomb structure with closed-cell foam would
solve this, the idea was rejected due to the additional
mass of 500 kg
Because of engineer’s protests of the LH2 tank
problems, the LOX tank was made out of an
Eventually, engineers started designing a Al-LI
LH2 tank, with mounting evidence of failure
– Even though the composite tank should be lighter
than a conventional skinned tank, the extra struts
needed to hold the honeycombed tank made the
With redirection of the fuel tank design, another
Ivan Bekey, a former NASA director, addressed
the Subcommittee on Space and Aeronautics on
April 11, 2001, stating that the X-33 had to
continue with composite tanks, because:
– “The principal purpose of the X-33 program is to fly
all the new technologies that interact with each other
together on one vehicle, so that they can be fully
tested in an interactive flight environment. If that is
not done, the principal reason for the flight program
This stunning testimony helped cancel the
Since this project had numerous setbacks,
and the X-33 was years behind schedule, and
grossly over budgeted, NASA terminated the
project in March 2001.
– The X-33 project was ended before ever being
flown, even though by 2001 there should have
been 15 test flights.
– Although the project was to be 3 years duration
and costing under $ 1 billion, it was 5 years with
$1.5 billion spent
– $1.3 billion spent on the project was public
Although the RLV program attempted to
foster industry competition for an efficient
means to orbit, it ended up as another costly
venture that mirrored the days of continued
pouring of money in a project until
Another difficulty was the required dual
vehicle use for both NASA and industry
Also, NASA wants a vehicle to also
service the space station, therefore it
must transport humans
– Space vehicles to launch satellites do not
require the overhead for human flight,
therefore this spacecraft will be cost
prohibitive for industry
Rather than create an all inclusive RLV that will
both launch satellites and transport persons to the
space station, a dedicated crew transfer vehicle
(CTV) could be built.
This CTV would be less expensive than
incorporating manned requirements into a second-
A CTV could be launched by an EELV.
Vehicle reliability is greater if cargo
requirements are not too
X-33 at the Space Station
The Phase III concept of total privatization was
– If industry backs out, will taxpayers have to foot
Since this privatized vehicle was to also launch
NASA and DoD satellites, the government may
have wanted a second non-privatized means to
launch payloads for national security.
– This extra competition would also scare industry
X-33 Launching a Satellite)
A SSTO craft must reach what is called
a "mass fraction" where the unfueled
vehicle weight is 10% of the weight of
the fully fueled craft.
– This is difficult to achieve without staging.
NASA came to the conclusion that the
current materials and technology was
simply not advanced enough for such a
The specific architecture of the X-33 limited
timely completion and cost-effective
LM’s admission of flaws to congress about
this project did not help the entire RLV effort.
– Contraversies abound: was this their way out
of the deal?! (C.F., SpaceProjects.com)
NASA’s one-best-way model is inferior to
multi-industry competition and trial and
– Consider the X-Prize competition.
Unexpected low demand for LEO and MEO
mobile communication satellites.
GEO satellites lasting longer.
NASA and DoD still deploys the majority of
– Result is launch service prices are not competitive.
The Air Force’s Evolved Expendable Launch
Vehicle (EELV) will subsidize technology
development, and this may drive some
launch costs down.
Allstar Network, X-33 Shuttle Replacement;
Berinstein, Paula, Making Space Happen.
Bromberg, Lisa, NASA and the Space Industry
Federation of American Scientists, Space Policy
Project, X-33 VentureStar , lifted May 3, 2006,
Space: The Free-Market Frontier, edited by
Edward L. Hudgins.
References – Cont.
SpaceProjects.com, X-33: How the Central
Planners at NASA Wasted Another Billion Tax
Dollars, lifted May 3, 2006, from:
Wikipedia, lifted May 3, 2006, from:
X-33/VentureStar - What really happened;