USA
DELTA 2-6925
1. IDENTIFICATION
1.1
Name
DELTA 2-6925
1.2
Classification
Ø Family
Ø Series
Ø Version
:
:
:
Ø Category
Ø Class
Ø Type
DELTA
DELTA 2
6925
:
:
:
:
SPACE LAUNCH VEHICLE
Medium Launch Vehicle (MLV)
Expendable Launch Vehicle (ELV)
1.3
Manufacturer
1.4
Development manager :
U.S. Air Force Space Division
L.A. Air Force Station, P.O. Box 92960
LOS ANGELES, CALIFORNIA 90009-2960
1.5
Vehicle operator
Mc DONNELL DOUGLAS SPACE SYSTEMS
Company
(with USAF or with NASA)
1.6
Launch service agency :
:
Mc DONNELL DOUGLAS SPACE SYSTEMS
Company
(MDSSC)
5301 Bolsa Avenue
HUNTINGTON BEACH
CALIFORNIA 92647
Mc DONNELL DOUGLAS SPACE
SYSTEMS
1.7
Launch cost
December 1992
:
Company
5301 Bolsa Avenue
HUNTINGTON BEACH
CALIFORNIA 92647
Tel.
: (714) 896 - 3311
Telex : 67 - 8426
Fax
: 714 - 896 - 1315
Between 45 and 50 M$ (1987) on the basis of one launch of a DELTA 2
serie launcher every 60 days.
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DELTA 2-6925
2. STATUS
2.1
Vehicle status
:
Out of service
2.2
Development period
:
Started January 1987
2.3
First launch
:
15.02.1989 (success)
3. PAYLOAD CAPABILITY AND CONSTRAINTS
3.1
Payload capability
3.1.1 Low Earth Orbits
3.1.2 Geosynchronous and Interplanetary Orbits
GEOSYNCHRONOUS TRANSFER ORBIT AND PLANETERY CAPABILITIES FROM ESMC
FIGURE 1
FIGURE 2
PERIGEE VELOCITY CAPABILITY FROM ESMC AND WSMC RESPECTIVELY
FIGURE 3
December 1992
FIGURE 4
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DELTA 2-6925
APOGEE ALTITUDE CAPABILITY FROM ESMC AND WSMC RESPECTIVELY
FIGURE 5
FIGURE 6
3.1.3 Injection accuary
All DELTA II configurations, including DELTA 2-6925, employ the DELTA Inertial Guidance System (DIGS)
mounted in the second-stage guidance compartment.
Orbit accuary for free-stage missions is primarily affected by the pointing and impulse error resulting from the
upper stage solide motor burn. To assist the user in mission planning, 3σ apogee altitude dispersion data for
a geosynchronous transfer orbit are presented in the figure hereunder, as a function of transfer orbit
inclination. The band shown in the figure indicates a typical range of pointing error at upper stage ignition.
The pointing error for any given mission depends on upper stage/spacecraft mass properties and spin rates.
Past DELTA experience, however, shows that most missions will typically fall within a 1 to
2.5 degrees pointing error band.
Transfer orbit perigee altitude errors for geosynchronous missions are typically < 5.6 km.
Three-sigma transfer orbit inclination errors over the inclination range shown in the figure are typically
0.2 < ∆ i < 0.6 degrees.
These data should be used as general accuracy indicators only. Detailed analyses are performed for each
specific mission, including the effects of individual mission requirements to define more precisely the
accuracy to be expected. Users are invited to contact the II Program Office for further information on orbit
accuracy.
FIGURE 7 - THREE-STAGE TYPICAL SYNCHRONOUS APOGEE ALTITUDE DEVIATION (km) - ESMC
December 1989
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3.2
DELTA 2-6925
Spacecraft orientation and separation
The third-stage DELTA separation sequencing system consists of a pyrotechnic timer to effect spacecraft
separation for redundancy, two timers are located on the attach fitting and incorporated into the third-stage
sequencing system. The sequencing system is initiated by a signal from the guidance computer before
second / third-stage separation.
FIGURE 8 - DELTA 2-6925 AND DELTA 2-7925 SEPARATION SYSTEMS
Ø Relative payload separation velocity: 0,61 to 2,4 m/s
Ø Deployement mechanism type: 4 springs release
3.3
Payload interfaces
3.3.1 Payload compartments and adaptors
Ø Payload fairing description: the fairing is an all-aluminium structure fabricated in two half-shells, consisting
of a hemispherical nose cap with a biconic section.
Ø Dimensions and mass of the fairing :
-
length: 8 488 mm
-
diameter: from 2 438 mm at the base to 2 896 mm at the midest portion
-
mass: 839 kg including thermal and acoustic insulation
December 1989
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DELTA 2-6925
Ø The allowable spacecraft envelope within the confines of the fairing is shown herebelow:
FIGURE 9 - PAYLOAD ENVELOPE, PAM-D STAR 48B CONFIGURATION (3712 ATTACH FITTING)
Ø The Payload Attach Fitting (PAF) 3712 is the interface between the upper stage motor of the three-stage
versions of DELTA II and the spacecraft.
The 3712 fitting is available with three forward flange configurations designated 3712 A, 3712 B, 3712 C.
The figure hereunder shows the capabilities of the three configurations in terms of spacecraft weight, cg
location and the following maximum clamp assembly preload associated with each configuration:
December 1989
3712 A
3 084 kg
3712 B
3 855 kg
3712 C
1 272 kg
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DELTA 2-6925
FIGURE 10 - CAPABILITIES OF THE THREE CONFIGURATIONS
Ø The actual selection of attach fitting configuration will be made after discussions with the spacecraft
contractor.
Ø As an option, the PAF is available without an NCS (Nutation Control System).
Ø New payload attach fittings are currently being studied; they take into account the use of the separation
clamp assembly interfaces that have been qualified for STS. They are listed below:
APPROXIMATE
DIAMETER (MM)
MAXIMUM FLIGHT
PRELOAD (KG)
SPACECRAFT PAF
FLANGE ANGLE (DEG)
115
3084.5
15
123
2585.5
20
136
3538
20
146
2993.7
20
164
3538
15
Ø A variety of removable doors can be provided in the fairing to permit limited access to the spacecraft
following fairing installation. Four standard access doors exit in the baseline fairing configuration.The RF
windows and access doors do note contain acoustic or thermal blanket material. Additionnal access
doors can be envisioned.
December 1989
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3.4
DELTA 2-6925
Environments
3.4.1 Mechanical environment
Ø Steady - state acceleration
For a three-stage DELTA vehicle the maximum steady-state acceleration occures at the end of thirdstage flight for payloads up to 1 180 kg. Above this weight, the maximum acceleration occurs at the end
of the first-stage burn.
FIGURE 11 - AXIAL STEADY-STAGE
ACCELERATION AT UPPER STAGE BURNOUT
FIGURE 12 - AXIAL STEADY-STAGE
ACCELERATION AT MECO VERSUS SECONDSTAGE PAYLOAD WEIGHT
Ø Vibration
The maximum expected sinusoïdal vibration flight levels (3 σ) are as follows:
FREQUENCY (Hz)
ACCELERATION (g's) (zero to peak)
Thrust axis
5 to 6.2
6.2 to 100
0.5 IN (Double amplitude)
1.0
Lateral axis
5 to 100
0.7
The spacecraft random vibration is best simulated by a properly performed acoustic test sed on the
environment described hereafter. Specific random vibration interface levels may be requested.
3.4.2 Acoustic vibrations
The acoustic environment for the 6925 version of the DELTA 2 vehicle is shown hereunder.
FIGURE 13 - INTERNAL FAIRING ACOUSTIC ENVIRONMENT FOR DELTA 2-6925
December 1989
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DELTA 2-6925
3.4.3 Shock environment
FIGURE 14 - MAXIMUM FLIGHT SHOCK LEVELS FOR THE DELTA 2-6925 AND DELTA 2-7925
VEHICLES DUE TO CLAMPBAND SEPARATION SYSTEM
3.4.4 Thermal environment
Ø Fairing
FIGURE 15 - VEHICLE FAIRING INTERNAL WALL TEMPERATURE AND EMITTANCE
December 1989
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DELTA 2-6925
Ø Upper-stage motor and spin-rockets
The motor Plume subjects the spacecraft to a heat flux profile depicted in the following figures.
FIGURE 16 - PAM-D PLUME RADIATION
AT THE SPACECRAFT SEPARATION
PLANE VERSUS BURN TIME
FIGURE 17 - PAM-D PLUME RADIATION
AT THE SPACECRAFT SEPARATION
PLANE VERSUS CENTERLINE DISTANCE
The spin rocket plumes subject the spacecraft to a maximum heat of 2 837 W/m² at the separation plane.
This heat flux is a 1 s duration pulse.
The upper-stage motor case temperatures are detailed herebelow.
FIGURE 18 - UPPER STAGE MOTOR CASE TEMPERATURES
3.4.5 Variation of static pressure within the fairing
Venting of the fairing is provided by a 64.5 cm² vent opening in the interstage and by other leak paths in the
vehicle.
December 1989
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DELTA 2-6925
The resulting fairing internal pressure history in represented in the following figure:
FIGURE 19 - DELTA 2 9.5 ft. FAIRING INTERNAL PRESSURE LIMITS
3.4.6 Spacecraft compatibility tests
Ø Sinusoïdal vibration test levels
Ø Acoustic test level
December 1989
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3.5
DELTA 2-6925
Operation constraints
Ø Launch rate capability (including all DELTA II versions): 12 in 1990, up to 18 in 1991.
Ø Ground constraints
The spacecraft agency must provide its own test equipment for spacecraft preparations, including
telemetry and ground stations.
Ø Integration process
FIGURE 20 - INTEGRATION PROCESS
A typical launch site operations flow involves about 73 working days.
The spacecraft is not required for mate with the DELTA third stage until about 10 working days prior to
launch.
FIGURE 21 - TYPICAL LAUNCH OPERATION FLOW
December 1989
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DELTA 2-6925
4. LAUNCH INFORMATION
4.1
Launch site
Dual pad launch capabilities are available in Florida at Launch Complex 17 on the Cape Canaveral Air Force
Station (CCAFS). In addition, a single launch pad is available at Vandenberg Air Force Base (VAFB) in
California to accomodate polar or other high inclination launches.
Ø Cape Canaveral Air Force Station, a part of the ESMC (Eastern Space and Missile Center), is located
approximately 80 km east of Orlando (Florida).
Launch Complex 17 consists of two launch pads (17 A and 17 B), a blockhouse, ready room, shops, and
other facilities needed to prepare, service and launch the DELTA vehicle. Launch information is shown
hereafter :
LAUNCH
PAD
LATITUDE
LONGITUDE LAUNCHER AZIMUT
(degrees North) (degrees West)
17 A
28.44687
80.56516
115.2
17 B
28.44559
80.56605
115.0
Launch Complex 17 is convenient for orbit inclinations from 28.5° to 51°.
In addition to the facilities required for the DELTA II launch vehicle, specialized facilities are provided for
the spacecraft:
Ø Payload processing facilities:
-
NASA - Provided hangars AO, AM, or AE,
-
ASTROTECH Space Operations in Titus-ville,
Ø Hazardous processing facilities:
-
NASA - Provided payload spin test facilities: Explosive Safe Area 60 (ESA 60), Spacecraft Assembly
and Encapsulation Facility 2 (SAEF 2), Cargo Handling Storage Facility at KSC or CCAFS;
-
ASTROTECH Space Operations
ASTROTECH of these facilities is controlled by the respective owners.
December 1989
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DELTA 2-6925
FIGURE 22 - LAUNCH COMPLEX 17, CCAFS
FIGURE 23 - DELTA SPACECRAFT CHECKOUT FACILITIES
December 1989
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DELTA 2-6925
Ø Vandenberg Air Force Base (CALIFORNIA)
The pad available at VAFB for DELTA launches, the Space Launch Complex SLC-2, is convenient for
orbit inclinations from 63° to 145°.
LAUNCH PAD
LATITUDE
(degrees North)
LONGITUDE
(degrees West)
LAUNCH AZIMUT
SLC-2
34.75
120.62
259.5
FIGURE 24 - VANDENBERG AIR FORCE BASE
FIGURE 25 - SPACE LAUNCH COMPLEX SLC-2 WSMC - PLAN VIEW
December 1989
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DELTA 2-6925
FIGURE 26 - SPACECRAFT SUPPORT AREA
4.2
Sequence of flight events
Typical sequence of events for a DELTA 2-6925 mission launched from ESMCR.
FLIGHT TIME
To
EVENTS
Main engine ignition
Solid motor ignition (6 solids)
56
62
63/64
December 1992
Solid motor burnout (6 solids)
Solid motor ignition (3 solids)
Solid motor separation (3/3 solids)
118
Solid motor burnout (3 solids)
124
Solid motor separation (3 solids)
265
Main engine cutoff
273
Blow stage 1/2 separation bolts
278
2nd stage ignition
305
Fairing separation
692
2nd stage engine cutoff
1 300
2nd stage engine restart
1 310
2nd stage engine cutoff command
1 360
Fire spin rockets, start 3rd stage sequencer
1 362
3rd stage separation
1 400
3rd stage burnout
1 600
Spacecraft separation
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4.3
DELTA 2-6925
Launch record data
LAUNCH DATE
NUMBER OF
SATELLITES
ORBIT
RESULT
14.02.89
1
Circular
Success
10.06.89
1
Circular
Success
18.08.89
1
Circular
Success
21.10.89
1
Circular
Success
11.12.89
1
Circular
Success
24.01.90
1
Circular
Success
14.02.90 (1)
1
LEO
Success
26.03.90
1
Circular
Success
13.04.90
1
GEO
Success
01.06.90 (1)
1
LEO
Success
02.08.90
1
Circular
Success
18.08.90
1
GEO
Success
01.10.90
1
Circular
Success
30.10.90
1
Circular
Success
08.03.91 (2)
1
GEO
Success
PAM-D2
07.06.92 (1)
1
LEO
Success
DELTA 2
6920
24.07.92
1
GTO
Success
REMARK
DELTA 2
6920
DELTA 2
6920
(1) 2 stage vehicle (DELTA 2-6920)
(2) 3rd stage: PAM-D2
Ø Failures: none
LAUNCH DATE
RESULT
24.01.94
CAUSE
.
Ø Success ratio: 100% (on 17 launches)
4.4
Planned launches
None of the 6 900 series.
December 1992
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DELTA 2-6925
5. DESCRIPTION
5.1
Launch vehicle
FIGURE 27 - VIEW OF DELTA 2-6925
5.2
Overall vehicle
Ø Overall length
Ø Maximum diameter
Ø Lift-off mass (approx.)
December 1992
: 39.62 m
: 2.44 m
: 220 t
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5.3
DELTA 2-6925
General characteristics of the stages
STAGE
0
1
2
3
CASTOR 4 A
-
-
PAM-D
THIOKOL
MDSSC
MDSSC
MDSSC
Length (m)
10.97
26.08
5.96
Diameter (m)
1.02
2.44
2.44
1.20
Dry mass (t)
1.5
Solid
Liquid
Liquid
Solid
TP-H8299
(Storable)
(Storable)
CTPB
RP-1
UDMH (A-50)
Oxygen
N2O4
HTPB 2000
96
5.9
Max.2
6.9
2.2
Designation
Manufacturer
Propellant :
Type
Fuel
Oxidizer
Propellant mass (t) :
10
Total
Ø Fuel
Ø Oxidizer
Ø Water
Tank pressure (bar)
Total lift-off mass (t)
11.5
Ø Upper part
DESIGNATION
SPIN TABLE
PAYLOAD
FAIRING
PAYLOAD
ATTACH
FITTING
Manufacturer
Mass
839 kg
Ø Launch vehicle growth: yes, there are 2 improved versions of DELTA 2-6925 planned in the future:
DELTA 2-7925 and DELTA 2A.
December 1989
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5.4
DELTA 2-6925
Propulsion
STAGE
0
1
2
3
Designation
TX - 780
RS - 27
AJ 10 - 118 K
STAR 48
THIOKOL
Rocketdyne
AEROJET
THIOKOL
9
1
1
1
Manufacturer
Number of engines
Engine mass (kg)
Feed syst.type
-
-
Mixture ratio
Chamber pressure
(bar)
47.6
Cooling
Specific impulse (s):
Ø sea level
230
Ø vacuum
262
303.5
319
Thrust (kN):
Ø sea level
480
919
Ø vacuum
378
912
42
66.7
Burning time (s)
52.5
228
450
85.3
Nozzle expansion
ratio
8.2
8:1
140
53.9
Yes
Restart capability
5.5
Guidance and control
5.5.1 Guidance
Ø Inertial guidance unit on first and second stages + DELCO processor unit.
5.5.2 Control
STAGE
0
1
2
3
TVC
Gimballing
Gimballing
Gimballing
Roll
-
-
-
Spinstabilized
30 to 10 rpm
Precision
-
-
-
-
Pitch, yaw
December 1989
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DELTA 2-6925
6. DATA SOURCE REFERENCES
1
-
DELTA 2 spacecraft users manual - July 1987
2
-
AIAA 89-2422: Castor solid rocket motors for launch vehicle propulsion - July 10 - 12, 1989
3
-
DELTA 2: A new generation - Mc DONNELL DOUGLAS SPACE SYSTEMS Company brochure March 1989
4
-
DELTA 2: Brochure released by Mc DONNELL DOUGLAS ASTRONAUTICS Company - June 1988
December 1989
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