Delta Sprint Library Report
3 Spacecraft Ascent

All elements of this report are tentative and may be subject to change.

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After Columbias new variant Delta II launch vehicles tentatively have these configuration numbers:

-  Delta Sprint Standard:                 792F-3.5T

-  Delta Sprint Spartan:                  7920H-3.5P

-  Delta Sprint Planetary:                792FH-3.5T

 

These are Delta II missions and configurations which have actually flown:

-  Mars Rover Spirit                      7925

-  Mars Rover Opportunity                 7925H

-  Globalstar (4 at a time)               7920-10L

The first number '7' represents the core stage and strap-on type and is the only Delta II core type currently in service, '8' being the core type for Delta III.  Delta IV departs from this numbering system.  The second number '9' represents the number of strap on motors (3 and 4 strap-ons can also be used.)  The third digit is the second stage type, here representing the AJ10-118K stage, currently the only second stage used on the Delta II (on Delta III/8930, the '3' second stage is incompatible with Delta II.)  The fourth digit/letter represents the third stage used.  '5' is a spin-stabilized solid motor called Star 48 ('6', not shown, is a smaller spin-stabilized Star 37FM, '0' means no third stage.)  After Columbia concepts use the Fregat, an upper stage currently in service with Starsem's Soyuz ST and FG commercial launch vehicles, but not for Delta II yet.  This is represented by 'F' and may become a number ('7' perhaps) if implemented.  The 'H' sometimes in the fifth character represents the larger type of strap-on motor for Delta III, which is compatible with the Type '7' Delta II core.  The hyphenated part represents a fairing other than the standard 9.5ft diameter metallic fairing used by most missions.  Two composite 10ft diameter fairings are available for Delta II commercial missions '-10' and '-10L'.  After Columbia's fairing designation '-3.5T' is a 3.5m diameter fairing large enough to accommodate both the Service Module and Fregat, while the '-3.5P' is a 3.5m diameter fairing large enough for only the Service Module (for sTandard and sPartan.)  Both of After Columbia's fairings require the exposed Descent Module for aerodynamic integrity.

 

3.1 Delta II 792F-3.5T

 

The primary ascent option for Delta Sprint Standard is the Delta 7920 with Fregat upper stage.  To determine the payload performance and feasibility of this arrangement, After Columbia's Terry Wilson has been configuring and testing the system in the Orbiter Simulator using the "generic" multistage.dll spacecraft module by Vinka (www.swing.be/~vinka).  The completion of this analysis is currently pending but a configuration of approximately 4500-5000kg is expected for Delta Sprint, with the Fregat upper stage carrying approximately the same amount of propellant as the Delta Sprint will weigh (its limit is 5350kg.)  The information used in the analysis is available from www.astronautix.com by Mark Wade.  Fairing mass for both 792F-3.5T and 792F-3.5P is assumed to be 1200kg, slightly heavier than the estimate of the standard fairing based on Steady State Accelleration chart found on Figure 4-18, Page 4-20 of the Delta II Payload Planner's Guide.  For each kg under this estimate, about 300g of mission mass can be added (i.e. 850kg fairing, a 350kg savings, would allow about 105kg to be added to Delta Sprint.)

 

3.1.1 Flight Characteristics

 

The following are approximate flight characteristics of the launch vehicle in various phases of the ascent as based on Orbiter Multistage ascent model Rev. 16's best run.  Units are Orbiter SI (Units used in Shuttle ascent & entry commentary for STS-107 and STS-33 for the benefit of those familiar with either of those missions.)

 

3.1.1.1 20 seconds:

Airspeed: 125 m/s (280 mph; 410 fps)

Altitude: 1.2 km (4000 ft)

Climb angle: 81 degrees

 

3.1.1.2 31 seconds:

Airspeed: 215 m/s (480 mph; 700 fps)

Altitude: 3.1 km (1.9 mi; 1.7 nmi)

Climb angle: 72 degrees

 

3.1.1.3 57 seconds Max-Q

Airspeed: 520 m/s (1160 mph; 1700 fps)

Altitude: 11.25 km (7 mi; 6.15 nmi)

Dynamic pressure: 50 kPa (1044 psf)

Climb angle: 53 degrees

 

3.1.1.4 65 seconds (1:05) groundlit boosters burn out

Airspeed: 620 m/s (1400 mph; 2000 fps)

Altitude: 14 km (8.7 mi; 7.6 nmi)

Climb angle: 48 degrees

 

3.1.1.5 97 seconds (1:37)

Airspeed: 1080 m/s (2400 mph; 3500 fps)

Altitude: 31.5 km (19.5 mi; 17 nmi)

Climb angle: 32 degrees

 

3.1.1.6 130 seconds (2:10) airlit boosters burn out

Airspeed: 1800 m/s (4000 mph; 5900 fps)

Altitude: 51 km (31.5 mi; 27.5 nmi)

Climb angle: 21 degrees

 

3.1.1.7 196 seconds (3:16)

Velocity: 3100 m/s (7000 mph; 10000 fps)

Altitude: 85 km (53 mi; 46 nmi)

Climb angle: 7 degrees

 

3.1.1.8 263 seconds (4:23) main engine cut off (MECO)

Velocity: 5000 m/s (11200 mph; 16400 fps)

Altitude: 115 km (71 mi; 62 nmi)

Climb angle: 9 degrees

 

At this point several things happen.  The first stage verniers continue to burn for three seconds to stabilize the vehicle from main engine cut off, at three seconds the verniers are cut off, the separation bolts fire for the first and second stages, and the Payload Escape Stage rockets fire to pull the second stage, Fregat and Delta Sprint spacecraft away from the first stage.  After three seconds the PES motors burn out.  Two seconds later the PES motors are jettisoned and the second stage (AJ10-118K) engine starts.  Three seconds later, the fairing protecting the Service Module, Fregat, and second stage from aerodynamic forces and PES motor exhaust are jettisoned.  In short, this will be a very spectacular 11 seconds for the crew and observers of on board camera feeds.  It could be a little scary for ground observers if they think the vehicle is falling apart!

 

3.1.1.9 350 seconds (5:50)

Velocity: 5700 m/s (12700 mph; 18500 fps)

Altitude: 125 km (78 mi; 67.5 nmi)

Climb angle: 0 degrees (level flight)

 

3.1.1.10 450 seconds (7:30)

Velocity: 6200 m/s (13900 mph; 20300 fps)

Altitude: 120 km (75 mi; 65 nmi)

Climb angle: 0 degrees (level flight)

 

3.1.1.11 688 seconds (11:28) Second stage engine cut off (SECO)

Velocity: 6500m/s (14500 mph; 21300 fps)

Altitude: 125 km (78 mi; 67.5 nmi)

Climb angle: Climb that would peak at 150km if left unpowered

 

Delta Sprint uses an unusual cut off mode of the Delta II second stage called "Propellant Depletion Shutdown" or PDS, which runs the second stage completely out of one or both of its propellants.  Most commercial missions use a command shutdown to ensure an accurate final orbit.  Delta Sprint has another stage to go, the Fregat, which can correct any insertion inaccuracies.  The Delta Sprint therefore sacrifices accuracy for performance.  The two stages remain connected for ten seconds to allow residual thrust to dissipate in the AJ10-118K engine.  The Fregat's motor ignites five seconds after separation.  At this point, with the spacecraft over the Atlantic outside the Gulf of St. Lawrence, Delta Sprint guidance takes over and uses the Fregat to complete the ascent.  The length of this ascent burn is not yet known, but probably about 6-10 minutes

 

3.1.1.12 880 seconds (14:40)

Velocity: 6800m/s (15200 mph; 22300 fps)

Altitude: 165 km (103 mi; 89 nmi)

 

Delta Sprint's ascent plane crosses the orbital plane of the International Space Station prior to the cut-off of the Fregat ignition unless Delta Sprint flies in a yaw attitude during ascent.  Delta Sprint does this to bring the crossing point, or 'node' forward to cut off of the Fregat engine and to bring the planes into closer alignment in space.  Doing this complex procedure allow faster rendezvous as the launch windows can be phased with the International Space Station rather than being merely aligned with it.  There is more flexibility in this rendezvous mode with Delta Sprint Standard than there is with Delta Sprint Spartan or Shuttle.

 

3.1.1.13 1180 seconds (19:40)

Velocity: 7850 m/s (17560 mph; 25750 fps)

Altitude: 150 km (93 mi; 81 nmi)

 

Delta Sprint's cut off is in perfectly level flight defining the periapsis of its orbit at the crossing node with the International Space Station.  About 44 minutes later at apoapsis, the Fregat executes a burn to both raise the orbit and bring the spacecraft's orbital plane into alignment and phase with the International Space Station.  On the Shuttle, a similar maneuver is called OMS-2.

 

3.2 Alternate Options

 

3.2.1 Delta II 7920-3.5P

 

The Delta Sprint Spartan ascent option lacking a Fregat upper stage has approximately a 5500kg total mass budget based on charts found in the Delta II Payload Planner's Guide available free of charge from Boeing and downloadable from their website at www.boeing.com.  A small amount of performance will be added by the in-flight firing of the PES (Payload Escape Stage.)  Ascent modelling in Orbiter in support of Delta Sprint Standard so far has indicated that the Payload Escape Stage will improve performance very slightly (about 1/4 of the mass of the PES motors.)  The Delta Sprint Spartan requires a more sophisticated Service Module for the rendezvous maneuvers and the mass budget for the Descent Module is likely to be smaller because of this.

 

3.2.2 Soyuz 11A511U

 

The most experienced launch vehicle of piloted spaceflight has sufficient payload impulse and the commercial version includes the Fregat upper stage as standard, allowing Delta Sprint Standard to ascend with little developmental pain associate with the launch vehicle.  The minimum inclination reachable by a Soyuz 11A511U launched from Baikonur is 51.6 degrees, and precludes Delta Sprint from planetary applications and future space stations using orbits of less inclination.  Even without China airspace considerations, a launch vehicle from Baikonur still cannot reach the ecliptic transfer orbit preferred for planetary missions, imposing major payload penalties for any vehicles wanting to use Delta Sprint or Soyuz as a crew transfer vehicle (this is something that the Soviet lunar landing program competing with Apollo had to contend with.)  Also, using Soyuz 11A511U as Delta Sprints launch vehicle introduces a common failure threat into both lifeboats for the International Space Station.  A single Soyuz failure could ground both spacecraft, forcing the abandonment of the International Space Station.

 

3.2.3 Ariane 44L

 

The Ariane 44L was the old favorite when Delta Sprint was first worked on shortly after the catastrophic failure of STS-107 for about a week.  In about April 2003, the Ariane 44L was removed from consideration as the craft's launch vehicle because the Ariane 44L went out of service.

 

3.2.4 Sea Launch

 

Sea Launch has lots of envelope and impulse for the job of ascending Delta Sprint Standard, Planetary or Spartan and is still open.  The obstacles are expected to be in the processing and crew ingress facilities as the fully fuelled launch vehicle is not erected until just before launch.  This last fact may actually work to advantage as the crew will not be on their backs for long before launch.  Sea Launch is also an open option for Delta Sprint II.

 

3.2.5 Delta III

 

Delta III has been removed from consideration as it no longer appears in the primary interfaces at www.boeing.com indicating that it may have been removed from service.  Regardless, it is an excellent launch vehicle.  Unlike the Shuttles failures, the two consecutive failures experienced by the Delta III were unforeseen, could be expected statistically, and could have happened on other launch systems using the same hardware.  The failure of Galaxy X would likely have happened to the Opportunity Mars Rover (Delta II), while the failure of Orion-3 would probably have happened to the first DSCS III launch on Delta IV.  After Columbia will miss the Delta III.

 

3.2.6 Delta IV

 

The first all-cryogenic launch vehicle, with an all-new first stage and engine, and a more conservative second stage.  Delta IVs commercial line comes in 5 configurations: M, M4.2, M5.2, M5.4 and H.  Of these five, M and H generate the most interest with After Columbia, with Low Energy payloads of  9000kg, and 25000kg respectively.  These numbers are reduced slightly for the ISS orbit.  Delta IV-M is being considered for follow-ons to Delta Sprint, such as increased capacity crew transfer vehicles (Delta Sprint II; the heaviest concept ascends on Delta IV-M4.2), and Delta IV-H is being considered for Yellowstar, a Bluestar proof of concept and orbital entry test vehicle (part of ISTS program) Outbound, a tether demonstrating space station as a prototype for Mars Direct with commercial potential and, of course, Ariane Sprint, a logistics vehicle for the Space Station which is also part of the Sprint Program.

 

3.2.7 Atlas V

 

After Columbia has not yet explored applications for Atlas V as we have not yet acquired this launcher's customer manual.

 

3.2.8 Ariane 5G

 

Ariane 5G is too big for Delta Sprint, and is being considered for Yellowstar, Outbound, and is the primary launch vehicle option for Ariane Sprint.

 

3.2.9 Proton 8K82

 

Proton 8K82 uses Baikonur as its launch site and suffers from the same limitations regarding inclination.  It also, like Ariane 5G, is too big for Delta Sprint.

 

3.3 Future Ascent Options

 

Future ascent options for Delta Sprint revolve around it being carried as a payload on ISTS (whereas OSP, based on illustrations, appears to have been intended as a more independent vehicle, never residing in a fairing or cargo bay, with progressively reusable stages being built around it.)  In its extended bailout role, it is intended that the ISTS be used for crew transfer, while Delta Sprint is carried without crew in the cargo bay.  During the period that ISTS is not crew rated, Delta Sprint would need to ascend on its original launch system.  The Crew Exploration Vehicle (CEV) concept under the new White House Plan supplanted OSP on 17 February 2004.  See Chapter 6 for more details


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