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NEXT GENERATIONS SPACE TRANSPORTATION SYSTEMS
Gennaro Russo
CIRA, Centro Italiano Ricerche Aerospaziali
Via Maiorise, 81043 Capua (CE), Italy
Phone +39 0823 623334, Fax +39 0823 623335, e-mail g.russo@cira.it
Abstract
Future generations Reusable Launch Vehicles (RLV) need to be The ISTP top level strategy is the following:
developed through an extensive use of flight demonstration. But, instead
of full scale, expensive, highly system-integrated flight vehicles, future • Reduce technical and business risks to achieve
research light vehicles need to be simpler and cheaper. Consequently,
the approach emphasizes sub-scale, unmanned, autonomous or remotely
significant increases in safety and reliability and
piloted vehicles to be flight tested at reduced cost and risk. drastic reduction in cost of 2nd generation manned
The Italian Aerospace Research Program PRORA has allowed up reusable launch systems with operations capability
to now the realization of a number of ground based laboratories and by 2012.
world-class facilities, like the 70MW Plasma Wind Tunnel SCIROCCO.
In 2000, the Unmanned Space Vehicles (USV) program was approved • Enable a competition at acceptable level of risk for a
dealing with technology maturation toward RLVs. 2nd generation RLV development decision by 2006
USV is a technology development program including theoretical, which could include Shuttle-derived and new design
numerical, on-ground experimental and flight test activities. It aims also
to realise experimental flying platforms that can complement and
concepts (including CTV).
integrate the available ground facilities at CIRA. • Develop revolutionary technologies for 3rd
USV was defined based on the belief that in the long run space generation RLV concepts to achieve safety and
access and re-entry will be guaranteed by aviation-like vehicles (SSTO- reliability comparable to commercial airlines.
HTHL, sometime called aerospaceplanes). Among others not less
important, such vehicles will require innovation and maturation in three • Ensure continued safe access to space through the
main areas: atmospheric re-entry, reusability, sustained hypersonic Space Shuttle Safety Upgrades until a replacement
flight. The USV Program includes thus technology developments along alternative has been demonstrated.
these three directions, up to their validation either on ground and on
board Flying Test Beds. • Support military and commercial applications to the
maximum extent possible.
Key-words: RLV, Re-entry, Experimental Vehicle, Space
Transportation System The major program of the ISTP is the SLI. This 4.8
B$ programme covers the period 2001-2006. The first
series of contracts has recently been awarded for a total
1. International Scenario Regarding RLVs of 767 M$. The driving requirements for these contracts
The USA is the country which has the largest experience are:
(also an operational one with the use of the Space
Shuttle) on RLVs. In 1996, the U.S. National Space • Focus on critical design trade studies and evaluation
Policy gave NASA the responsibility to initiate criteria emphasising safety and affordability as well
partnership with industry to jointly develop reusable as performance (with the goal of 100 times safer and
launcher technologies, based on the assumption that the 10 times cheaper than the Space Shuttle).
satellite market development would support the • Inclusion of safety and economic analyses as equal
commercial development of a new reusable launch partners in the design team.
vehicle around the turn of the century. The program • Use architecture studies to identify, drive, and
pursued aggressive SSTO (single stage to orbit) quantify critical technology needs.
technologies with compressed schedule and limited
budget. In 1999, NASA initiated a new series of system
• Pursue technologies critical to a wide range of
architectures, but with well-defined and controlled
activities, the Space Transportation Architecture Studies
risk mitigation plans.
taking into account the evolved market conditions, which
In Japan the concentration of the efforts toward the
led to the definition of an Integrated Space Transportation
development of the H-IIA expendable rocket has lead to
Plan (ISTP).
placing on hold the development of an operational
The ISTP includes the following separate programs:
HOPE-X re-entry vehicle, limiting the work to transonic
• Space Shuttle Safety Upgrades to continue improve flight demonstration and basic technology activities for
the Space Shuttle reliability and operability. propulsion, cryogenic tanks and thermal protection
• Space Launch Initiative (SLI or 2nd generation RLV) systems for future RLVs.
to prepare the ground for a Shuttle replacement In preparation for the HOPE-X, Japan already
decision in 2006 by the U.S. government, for the new launched several experimental vehicles, namely:
vehicle operational around 2012. HYFLEX (launched in 1995 to study the hypersonic
flight regime), OREX (with a capsule shape, launched in
• 3rd Generation RLV focused on more long term
1994 to collect information on the structural design and
technologies (e.g. air-breathing).
construction of the vehicle re-entering the atmosphere)
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G. Russo
and ALFLEX (with a test campaign conducted in mid- focused on elements of the re-entry test vehicle X-38 V-
1996 to examine the automatic landing equipment and 201 foreseen in 2003. This vehicle will perform an end-
GNC algorithms). The High Speed Flight Demonstrator to-end demonstration of the CRV mission, including the
(HSFD) to study transonic regime, is scheduled for ascent in the Space Shuttle cargo bay, the on-orbit and re-
launch in 2002. After the recent H-II flight, discussions entry phases, the automatic landing phase under parafoil.
have restarted, especially in the Space Activities Under a single cooperative agreement among NASA,
Commission, on RLVs, with a special emphasis on ESA (through the Applied Re-entry Technologies
manned systems. Program) and DLR (through the national TETRA
Russia developed a reusable vehicle, Buran which program), Europe provides the X-38 program with
flew only once in 1988. In the Buran development several contributions (e.g. aerodynamic shape definition
programme, six full scale functional mock-ups were built and aerothermal database, definition of flight control
and three experimental vehicles were flown: laws, hot structures, TPS, mechanisms etc.).
Although not all the program elements will be
• Buran Analogue for horizontal flight tests applicable to RLVs, the X-38 V-201 flight test is
• BOR-4 for hot structure tests expected to provide in-flight verification of thermal
• BOR-5 for aerodynamic tests protection blankets and hot structure design concepts,
associated technologies and operational techniques; such
Despite the lack of an operational RLV and despite
a flight test will provide useful data for the development
today’s economical difficulties, technological know-how
of future reusable space transportation systems.
as well as hardware and facilities are still available in
The ISS CRV vehicle is conceived as a reusable
Russia.
transportation system, in the form of a lifting body,
Recently, Khrunicev has performed studies and
whose mission is under demonstration through several
developed an engineering model of Baikal, proposed as a
atmospheric drop tests and the X-38 V201 orbital re-entry
reusable first stage for the Angara family.
flight.
In Europe several system studies were conducted
The present European participation to the CRV
during the 80’s to investigate possible concepts for a
consists mainly in contributions in the field of re-entry
European RLV, both at ESA level (FLS, WLC, RRL,
aerothermodynamics, hot structures, thermal protections,
FESTIP as well as with the Hermes program which dealt
mechanisms and manned technologies (man-machine
with some studies, technologies and facilities related to
interface, crew seats).
RLVs), and at national level (HOTOL, SAENGER,
In 1999, DLR set up the ASTRA national program
TARANIS, STAR-H). In 1998, ESA flew the ARD
dedicated to technologies for future launch vehicle
capsule which gave valuable information on the
applications. A major development in this program is the
atmospheric re-entry.
Phoenix flying test bed for the demonstration of the
The FLTP (Future Launchers Technologies
automatic landing techniques. The program also includes
Programme) was approved in 1999 with the objectives of
system work on selected vehicle concepts and on-ground
confirming the interest of launcher reusability under
technology developments in the propulsion, structures,
realistic assumptions, and of identifying, developing and
and avionics and GNC this being mainly targeted to the
validating the required technologies. The unbalanced
Phoenix test-bed.
participation to the programme and the problems in
ASI funds at national level the FAST-2 program
implementing procedures brought to the decision to put
including some RLV technology developments in areas
FLTP on hold.
considered of strategic industrial interest, mainly in the
Several programs are on-going in Europe, both at
field of turbomachinery, liquid oxygen/ hydrocarbon
national level (e.g. ASTRA, PRORA-USV) and ESA
combustion, advanced metallic cryogenic tanks, metallic
level (X-38/CRV), to foster the development of some of
thermal protections and aerothermodynamics.
the technologies required for future reusable space
transportation systems. Moreover, some specific
technologies are being developed within the ESA TRP 2. The USV Program
and GSTP programs, which also have an interest for
The lack of physical knowledge and the large sensitivity
RLVs.
of the design solution on main parameters impose that
Even if the objectives and the requirements of these
future generation Reusable Launch Vehicles (RLV) be
programs are different, technological activities of interest
developed through an extensive use of flight test and
for future RLV developments are being carried out.
demonstration. The lack of available funds, from another
However, these activities are relatively fragmented and
side, imposes the search for solutions that can combine
dispersed.
low development costs with sufficiently effective results.
The X-38 program, led by NASA, is directed towards
So, instead of expensive, highly system-integrated
the design, development, fabrication and flight testing of
flight vehicles, future research light vehicles need to be
a re-entry vehicle, the X-38, that would serve as the
looked at.
prototype for the International Space Station Crew Return
As a direct consequence, the approach to be used
Vehicle (CRV). Beside the participation to the definition
emphasises small-scale, unmanned, physically significant
of the vehicle shape and the establishment of the
rather than geometrically similar, vehicles to be flight
associated aerodynamic and aerothermal databases, the
tested at reduced cost and risk.
ESA contribution to this programme is specifically
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G. Russo
The Italian Aerospace Research Program PRORA has PRORA includes thus technology developments along
allowed up to now the realisation of a number of ground these directions up to their validation either on ground
based laboratories and world-class facilities, like the and on board Flying Test Beds.
70MW Plasma Wind Tunnel SCIROCCO. In 2000, the With the goal of an incremental test objective
Unmanned Space Vehicles (USV) program was approved approach, starting from a proposal made in 1940’s and
dealing with technology maturation toward RLVs. recently re-appreciated and tested under the label of
USV was proposed as a scientific and technological “rockoon” (from rocket + balloon), PRORA-USV has
knowledge development effort toward future generations indicated in an experimental vehicle launched from a
RLVs maturation. Its second important objective was stratospheric balloon the best compromise between
defined as the integration of available on ground testing vehicle performance, test objectives and development
capabilities (laboratories and facilities) with Flying Test costs.
Beds, i.e. with experimental flying laboratories. The USV program has the final aim to flight test a
The USV program was defined based on the belief number of technologies during a full orbital re-entry, with
that in the long run space access and re-entry will be energies of the order of 25 MJ/kg. To arrive at proper
guaranteed by aviation-like vehicles (SSTO-HTHL, maturation of flight capability and efficient
sometime called aerospaceplanes). Such vehicles will be experimentation, a step-by-step approach has been
characterised by so many important innovative solutions selected that is characterised by an “increasing mission
that brought for example to the cancellation of the complexity”. In fact, the program includes some
National Aero Space Plane (NASP) program in USA. intermediate steps (Flying Test Beds, FTBs) that are
Looking at nearer term, it is today commonly believed characterised by the foreseen achievement of concrete
that 2nd generation RLV will be a Two Stage To Orbit technological and system objectives aimed at execution
(TSTO), with the first stage able to accelerate up to Mach of technological flight tests and contemporaneous
6-8 for staging, thus performing a more or less real acquisition of good confidence level about the
sustained hypersonic flight before returning and landing. development of the selected technologies.
The second stage will be able to further accelerate in The USV road-map is shown in Fig. 1 where it is
order to reach orbital speed at the desired altitude, carry evidenced that the program is subdivided into two parts.
on the mission and re-entry the earth atmosphere finally Part 1 shall last three years (2002-2004) with the
landing on a runway. ambitious goal to fly the first two missions (DTFT, SRT).
Some of the fundamental technological areas Part 2 shall last another 3.5 years (2005-2008). This
requiring innovation and maturation assumed as of planning will guarantee, among others, a proper national
national specific interest were identified as: technology readiness in 2007-2008 when everybody
agrees a final decision on the launch of the new RLV
- atmospheric re-entry, development will probably be taken.
- sustained hypersonic flight,
- reusability.
2000 2005 2010 2015
<100 kg payload and/or Techn.
Payload
Passenger Experiments
Semi-Reusable Winged-Body.
3 FTBs
Configuration evolution
Balloon for DTFT, SRT, HFT.
Launching Stage
VEGA for ORT
DTFT SRT HFT ORT
Dropped Sub-orbital Hypersonic Orbital
Transonic Re-entry Flight Re-entry
AEROSPACEPLANE
TECHNOLOGIES
Flight Test Test Test Test
PRORA 8/2003 7/2004 8/2005 9/2007
USV Part 1 Part 2
Transonic/Supersonics
Re-entry
Hypersonics
Fig. 1 – USV Program Road Map
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G. Russo
− Validation of the propelled FTB configuration
3. The USV Experimental Missions
equipped with expendable solid motor
The USV will perform a set of missions defined in such a − Verification of the Balloon + Propelled Vehicle
way as to acquire the capability to manage several aspects (Rockoon) System
that are peculiar of a future generations RLV. − CFD validation and PWT-Flight correlation
In order to reduce costs, some operational − Passenger experiments (for examples Health
assumptions have been taken: Management, UHTC, TPS, Reentry GNC,
− Launch shall be made via aerostatic Propulsion, …)
stratospheric balloon
− Baseline Launch Base shall be the ASI It is important to note that being a sub-orbital mission,
station of Trapani-Milo in Sicily SRT is characterised by available low energy levels
− The vehicle shall be recovered on the sea (around 2 MJ/kg). In order to try to satisfy the above-
without implementing TEAM and automatic mentioned objectives, it is necessary to fly non-standard
landing, but via parafoil. trajectories. In fact, the nominal trajectory has been
The USV system shall perform the missions described selected by imposing the condition to maximise the heat
here below. flux, rather than minimise it as normally done when the
Dropped Transonic Flight Test (DTFT) target is just to re-enter in the safest way possible.
The balloon achieves a floating altitude of 24.2 km, then
the first USV Flying Test Bed named FTB-1 is dropped.
At about 16 km the vehicle will experience the maximum
Mach of 1.05 at 8.8 degrees AoA (see Fig. 2).
The main objective of this 1st CIRA flight test is to 24.2 km
verify the stability, manoeuvrability and controllability of
the FTB-2 vehicle when flying in transonic conditions. A
secondary but also important objective of DTFT is to
have operational and technical confidence on:
− Separation from Balloon and manoeuvres during
the first few seconds of the mission
16 km
− Capability to cope with the recovery phase Mach = 1.05 @
(parafoil deployment, capability to foresee and AoA = 8.8 deg
achieve the landing zone, ….)
− Duplication of typical reentry final phase, with
specific regard to SRT (second mission) Fig. 2 – Outline of Dropped Transonic Flight Test
− Codes and design flight validation (DTFT)
− Passenger experiments shall be arranged on
board.
Useful testing flight can extend down to subsonic
conditions of Mach 0.6. This happens at a dynamic
Hypersonic Flight Test (HFT)
pressure of 4.3 kPa and at an altitude of about 13 km
The balloon achieves a floating altitude of about 35 km.
where the drogue start to inflate.
After the release from the balloon the main motor is
ignited, pushing the vehicle to reach its maximum speed
Sub-orbital Re-entry Test (SRT)
along a horizontal flight path. It is foreseen that USV will
The balloon achieves a floating altitude of about 35 km;
fly above Mach 6 for at least 25 sec and will reach the
and after the release from balloon the main motor is
maximum speed at Mach 7.
ignited accelerating the vehicle along a sub-orbital
These conditions are achieved at a constant attitude of
trajectory up to a maximum altitude of about 120 km.
3 deg and a constant altitude of about 30 km, the latter
Then the vehicle starts the re-entry phase along a
being determined by the fact that, while accelerating
trajectory designed to maximise heat fluxes, achieves the
horizontally, the vehicle drops down until sufficient
maximum heat flux at about 25 km and keep a heat flux
velocity and lift are reached, as indicated in the sketch
higher than 650 kW/m2 for about 15 sec (see Fig. 3). The
Fig. 4. Objectives of HFT are:
main objectives of SRT are:
− Acquisition of operational and technical confidence 120-km
on re-entry aspects by duplicating a large part of
typical reentry trajectory (sub-orbital flight) in real
conditions (pressure-thermal flux)
− Provide the research community with a Flying Test 2
650-kW/m ; 15 “
Bed able to test advanced materials under very
severe conditions 35-km
− Flight test the second USV hardware (FTB-2). It will
be characterised by a design refinement with respect
to FTB-1, after DTFT
Aerotecnica Missili e Spazio Vol. 81 – 2/2002
Fig. 3 - Outline of Sub-orbital Re-entry Test (SRT)
68
G. Russo
− Acquisition of operational and technical
confidence about horizontal sustained hypersonic
flight in terms of aerodynamics and flight 25”
M > 6 forM = 7; Mmax = 7
mechanics behaviour prediction
35-km
− First European Mach 7 Sustained Flight and
second civil test in the world after the X-15
experience
− Utilisation of the same FTB-2 hardware used for
SRT, after adequate refurbishment.
− CFD validation and WT-Flight correlation Fig. 4 - Outline of Hypersonic Flight Test (HFT)
− Passenger Experiments (for example, Health
Management, UHTC, Hypersonic GNC, Air- − General shape as slender as possible
breathing Propulsion, ...) − Maximum length 7.5 m
− Maximum wing span 3.5 m.
A further mission is being considered that is dubbed
HFT-LP, standing for Hypersonic Flight Test with Liquid The vehicle will be used as a flying test facility, so a
Propulsion engine. It will be essentially a repetition of good level of modularity has to be implemented:
HFT but using a new 10 t class LOx-Methane engine
under development at FiatAvio. So, the objectives shall − The nose and the leading edge shall be removable
be summarised as: in order to be able to test different materials at
different heat load conditions
− Second European Mach 7 sustained Flight − It shall be possible to install at least 2 classes of
− Modified FTB-2 motors
− New LOx-HC motor flight test − The TPS shall be completely removable.
− Same hardware as SRT The design approach for the winged vehicle definition
− Passenger Experiments (for example, Health was defined on the basis of the general constraints that
Management, UHTC, Hypersonic GNC, ...) frame the program:
− Reduced development time (1st flight in mid-
Orbital Re-entry Test (ORT)
2003) and budget w.r.t. very ambitious objectives
The final USV mission is dubbed ORT and will
of the 4 missions
implement a full orbital re-entry experiment. A third
hardware FTB-3 will be realised having less slender − Very different flight conditions with similar
configuration than previous vehicles. It will be brought at vehicles
an low earth orbit of 200 km by the VEGA small − Long term plan (final experimental mission at
launcher. Major objectives are: end 2007).
− Execution of a multi-objective mission oriented On the basis of that, the most important concepts that
toward flight demonstration of future RLV have applied at system level are:
generation technological advances
− Reaching LEO (First CIRA Experience) − Trade-off areas reduced to the possible minimum
− Management of a complex mission of a complete − Robust design approach not only in terms of
multi-stage system [VEGA (1st stage) + FTB-3 design margins but also in terms of mid-long
(2nd stage)] term H/W availability, programmatic risks,
decision margins on several areas (e.g. choice of
− Small payload to LEO demonstration.
the main motor, minimum radius at nose, and
other topics).
4. The USV Configuration
The hypersonic mission HFT is “driving” for the
The general shape definition criteria of the FTB vehicles
definition of several requirements and characteristics of
comes on one side from the objective to simulate to a
the vehicle (aerodynamic performances and shape, motor
certain extent the environment typical of future
performances, ….). The SRT re-entry mission is the
generations launch and reentry vehicles.
sizing case for what concerns the thermal and mechanical
On the other side, it has to be considered as a
loads. Several hypotheses have been considered in the
requirement directly derived from the willingness to
definition of the mission in terms of vehicle mass, release
address topics concerning 3rd generation RLV and
altitude, maximum altitude during coasting, type of
beyond. As a matter of facts, that sort of RLVs will spend
motor.
most of energy during the atmospheric flight so their
The system configuration has been defined to have a
aerodynamic characteristics must be much better than the
vehicle intrinsically stable and controllable in all flight
1st and 2nd generations ones.
conditions. The centre of gravity (CoG) is determinant,
The main shape requirements are the following:
and has shown to range between 65% and 67.5% from the
− Radius at nose 10 mm vehicle nose.
− Maximum wing profile thickness < 8%
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The external shape has to be considered as a equipment. In-depth probes are to be installed in the
requirement, aimed at translating the meaning and the Thermal Protection System, aimed to detect temperature
main objectives of PRORA. These requirements have and incoming heat fluxes, both for monitoring critical
been translated in an 8% maximum wing profile zones and for validating/tuning the aerothermodynamic
thickness, and a fuselage diameter as small as possible prediction tools used in the design. Similarly, the
compatibly with the mechanical problems. distribution of pressure ports on the airframe shall be
The total vehicle mass is constrained by the need to designed in such a way to allow the completion of the
be launched by existing balloons. The vehicle dry mass aerodynamic characterisation of the vehicles.
has been estimated around 1200 kg. The ADS shall exploit both nose ports and mid
The general configuration of the vehicle is shown in
Fig. 5. The structure is sized on the basis of the loads
induced by the SRT mission. The wing box sizing
criteria, in any case, could be the stiffness needed to cope
with wing flap induced flutter.
Fig. 6 shows a sketch of the flight instrumentation
system with the identification of suitable zones for the
measurements of pressure and temperature/heat.
The measurement instrumentation of the USV
vehicles is aimed to reconstruct the flight history in all its
major features, to support the navigation and flight
control functions, to monitor the state of the vehicle itself Fig. 5 – USV Configuration
and to provide people with all data necessary for the
verification of the accomplishment of the scientific and
fuselage ports, for static pressure estimate. Wings, tails
technological goals. Ground tracking, a GPS, an inertial
and base pressure distributions are also to be detected, so
measurements unit and accelerometers will allow the
as wing flaps and rudders efficiency. Stagnation points
reconstruction of the trajectory, included free stream
temperatures and fluxes are envisaged to be monitored;
Mach number, and of inertial attitude. The Mach number,
moreover, base temperatures will give a check for the
as well as the thermal free stream parameters, will also be
exhaust plume radiation extent. A dense distribution of
estimated on the basis of on board pressure and
temperature probes in the windward mid section shall
temperature measurements.
allow the detection of laminar-turbulent transition points.
The aero Flight Control System (FCS) is based on the
The experimental Flying Test Beds to be developed in
accurate knowledge of the angles of attack, whose
the course of the USV program are supposed to be
detection is obtained by a pressure measurements based
recovered. Although automatic landing technology and
system (Air Data System). Like for Mach number, a
features are excluded by the program, each mission is
redundant estimate based on inertial attitude and ground
designed and planned to minimise the probability of
velocity will be performed on board.
loosing the vehicle.
As USV will experience a variety of conditions
Fig. 6 – Flight Instrumentation System
during its flights, the ADS has to work in wide ranges of One of the major concerns in this direction is the
Mach and attitude, this implying the exploitation of utilisation of stratospheric balloons, being their reliability
different assemblies of pressure ports, the use of more relatively poor (0.85-0.90). However, this is not the only
than one type of transducers and the implementation of weak or risky point or element. The already investigated
suitable switches in the onboard flight control software. or considered “counter-measures” include:
Monitoring of the vehicle will include inside pressure and • Shock-absorbing protection system attached to the
surface temperatures and strains on structures and lower side of USV in order to prevent vehicle
Aerotecnica Missili e Spazio Vol. 81 – 2/2002
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G. Russo
damage in case of problems at very early stage of the • USV program needs
ascending phase (some m/s) • CIRA background (increase existing
• once the balloon has reached a certain altitude (from competencies, promote new ideas)
some 300 m altitude) any failure of the ascending • Balance the II and III generation level research
system can easily be overridden by using the safety activities
parachute included in the balloon chain The research lines selected up to now are illustrated in
• even not analysed yet, air bag devices can be Tab. I and Tab. II. They are classically grouped in
mounted as further impact absorbing element Material & Structures, Aerodynamics &
• finally, a Flight Termination System (FTS) is Aerothermodynamics, Propulsion, Heat Management,
foreseen, in order to maximise the safety in case of Health Management, Flight Systems.
serious contingencies and consequent mission The final iteration to refine this Plan is running at
abortion. FTS shall be defined in a way to guarantee time of writing, so adjustments are expected.
that the system and propellant fragmentation fulfil
general safety requirements. 6. Conclusions
The results of the phase A activities of the USV
5. The Enabling Technologies Program Plan Program have been fully successful, collocating the
As USV is a technology development program, its overall program itself well within the international scenario.
main objective is to provide a focus for identification, These results can be summarised as follows:
development and validation of a number of key − The main objectives of PRORA have been well
technologies known to be representative of needs for understood and translated into mission and system
future generations reusable space transportation vehicle. requirements
More specifically, the Enabling Technologies Program − The feasibility of the program has been demonstrated
Plan included in USV is intended to deal with either 2nd − Large project margins exist, both in technical and
as well as further generations RLV, according to the programmatic terms
NASA terminology. − Meaningfulness of each single element of the
Under this assumption future space transportation program has been assessed with respect to the next
systems will have to satisfy many contemporary generation RLV technology needs identified by ESA
requirements of air transportation such as economy, − The Enabling Technologies Program Plan has been
reliability, prolonged service life and short turn around essentially identified, even if still waiting for final
time. For this purpose, the methods and processes freezing.
customary to space transportation must be combined with
7. References
those of aeronautics. A merge of aeronautic and space
technologies seems probable and will be expressed in the [1] “Future Launchers Preparatory Programme (FLPP) -
vehicle configuration. Initial Programme Proposal”, ESA/PB-
The development of such an aerospace vehicle ARIANE(2001)112, 22 Oct. 2001
presupposes in particular the maturation of some specific
macro-technologies: [2] G. Russo, S. Borrelli, G. Borriello, A. Denaro, F.
Betti, A. Accettura, “Access to Space: Flying Test
1. Atmospheric Re-entry - the aerospace vehicle has to Beds as a Need for Long Term R&D“, 2nd Int.
“handle” the typical large thermal loads encountered Symp. on Atmospheric Re-entry Vehicles and
during re-enter to earth from LEO, due to the Systems, Arcachon 26/29 March 2001
necessity of reducing the vehicle speed from Mach
25 or so down to few hundreds of km/h at landing; [3] G. Russo, G. Borriello, S. Borrelli, F. Mura,
“Preliminary Design And Performance OF The
2. Hypersonic Flight – we suppose that the future space PRORA-USV Experimental Vehicle“, 2nd Int.
vehicles will have to fly for large part of its mission Symp. on Atmospheric Re-entry Vehicles and
to speed much greater that the speed of the sound, Systems, Arcachon 26/29 March 2001
and will have to manoeuvre in such conditions in
security, having also to “handle” the heavy thermal [4] G. Russo, “Next Generations Space Transportation
loads generated from the friction with the air; Systems: R&D and Need for Flying Test Beds”,
3. Reusability - the most important characteristic from AIAA/NAL/NASDA/ISAS 10th Int. Space Planes
the operating point of view is the tendency to be as and Hypersonic Systems and Technologies
much like current airplane. This translates in the Conference, Kyoto (Japan) 24/27 April 2001
reusability concept. [5] G. Russo, A. Capuano, “The PRORA-USV
Program”, 4th European Symp. on
Given these elements, the USV Enabling Aerothermodynamics for Space Vehicles, CIRA,
Technologies Program Plan has been drafted taking into Capua (Italy) 8/11 October 2001
account the following criteria:
[6] M. Serpico, A. Schettino, “Preliminary
• Italian industrial needs and competencies
Aerodynamic Performances of the PRORA-USV
• European scenario (avoid duplications,
Experimental Vehicle”, 4th European Symp. on
strengthen the Italian position)
Aerotecnica Missili e Spazio Vol. 81 – 2/2002
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G. Russo
Aerothermodynamics for Space Vehicles, CIRA, TECHNOLOGIES Priority
MATERIAL & STRUCTURES
Capua (Italy) 8/11 October 2001
• Advanced Thermal Protection System (TPS)
[7] S. Borrelli, M. Marini, “The Technology Program in • Advanced CMC (UHTC) 1
• Hot Structures 2
Aerothermodynamics for PRORA-USV”, 4th • Tanks
European Symp. on Aerothermodynamics for Space • Filament Wound CFRP Cryo-Tank (oxidyser & eventually fuel) 1
Vehicles, CIRA, Capua (Italy) 8/11 October 2001 • Elastomeric liner for Cryo Tank (oxidyser & eventually fuel) 1
• Advanced Tanks based on Nanotechnology 2
AERODYN. & AEROTHERMODYN.
• New Configurations 2
• Extrapolation to Flight 1
TECHNO Atmospher Sustained Reusability • Laminar-Turbulent Transition 1
LOGY ic Hypersonic • Base Flow 2
• Real Gas, catalyticity 2
FOCUS Re-Entry Flight • Control Surfaces 1
PROPULSION - LOx/HC Engine
FLIGHT SRT, ORT HFT DTFT, • System Level
TEST SRT, HFT, • Optimal cycle (GG, SC, Expander, Bleed,…) 1
• Sub-systems identification 2
ORT • Propellants
• Materials compatibility 2
ENABLIN - Transition - Transition - UHTC • Sub-System Design
G - Extrapolat - Extrapolat - Hot • Supercritical injector plate
High temperature materials 1
TECHNO ion to ion to Structures Combustion instabilities damping/detuning devices 1
LOGIES flight flight - Heat • Ablative cooled combustion chambers 2
- Base - New Mgnt • Ablative cooled nozzles 2
Flow configurat - Health • Engine Modelling
• Mass/energy budget analisys tools 1
- Real Gas ions Mgnt Syst • Turbulent combustion models for combustion chambers 1
Effects - Control - LOx-HC • Combustion modelling by LES 1
- Micro- Surfaces rocket PROPULSION - OTHER TOPICS
Aerother - UHTC • Hydrocarbon Liquid Ramjet/Scramjet Engines 1
• Hybrid Propellant Ramjet/Scramjet 2
modyn. - Cryotank • Flight Experiments 2
- Control - Smart HEAT MANAGEMENT
Surfaces Structure • Design Methodologies 2
• Heat pipes based cooling panels 2
- UHTC - Heat
• Wing leading edge con raffreddamento basato su heat pipes 2
- Heat Mgnt • Active cooled panels (LH2, HC cracking) 2
Mgnt - LOx-HC INTELLIGENT & INTEGR. HEALTH MANAGEMENT
- Re-entry rocket • HW e SW Innovative Architectures 1
• Data Fusion 1
GNC - Air- • Algorithms 1
breathing • Modular Avionics 1
Prop • Innovative EGSE, maintenance & re-design capability 1
- Hypersoni • Sensori Ottici a Reticolo di Bragg per Alte Temp. 2
FLIGHT SYSTEMS
c GNC • Re-entry GNC 1
• Hypersonic Flight GNC (M<7) 1
Tab. I - Relation between selected technologies and USV • High Performance Bus 2
Flight Test Beds
Tab. II Selected Enabling Technologies
Aerotecnica Missili e Spazio Vol. 81 – 2/2002
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