Author Topic: Atlas V 421 - SBIRS GEO-5 - Cape Canaveral SLC-41 - 18 May 2021 (17:37 UTC)  (Read 45327 times)

Online FutureSpaceTourist

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https://twitter.com/ulalaunch/status/1391782849674625031

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LAUNCH ALERT! #AtlasV will launch #SBIRSGEO5 for @SpaceForceDoD and @USSF_SMC next Monday from Cape Canaveral. Liftoff time is 1:35pmEDT(1735 UTC). #SBIRS satellites detect and track missile launches worldwide to provide early warnings and save lives. bit.ly/av_sbirsgeo5

Offline LouScheffer

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I believe it's <1500

I already calculated the GTO delta-v in a previous reply.

https://forum.nasaspaceflight.com/index.php?topic=47477.msg2233874#msg2233874
The SBIRS satellites do not reduce the inclination all the way to zero, so the delta-V will be less than the calculation used for GEO comsats (that's the 1633 m/s).  It  is left to the interested reader to calculate the delta-V to the 4.3o inclination used by SBIRS GEO-4.

Offline Newton_V

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Looking back through this thread, the expectation of the Atlas V 421 DV to GSO, or 4 deg GSO, is incorrect, as the assumption of the SV weight is incorrect.   Additionally, there is the weight of the secondary dispenser and separated payloads.
« Last Edit: 05/11/2021 03:03 am by Newton_V »

Offline ZachS09

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I believe it's <1500

I already calculated the GTO delta-v in a previous reply.

https://forum.nasaspaceflight.com/index.php?topic=47477.msg2233874#msg2233874
The SBIRS satellites do not reduce the inclination all the way to zero, so the delta-V will be less than the calculation used for GEO comsats (that's the 1633 m/s).  It  is left to the interested reader to calculate the delta-V to the 4.3o inclination used by SBIRS GEO-4.

I never said anything about the SBIRS-GEO satellites reducing the inclination to 0. I just assumed the inclination would be slightly lower than 16.88 degrees (could’ve been around 15 degrees with the same perigee on the mission kit).

P.S. Here’s the GTO delta-v for SBIRS-GEO 4 upon payload separation (per Spaceflight101.com).

Perigee: 185 kilometers

Apogee: 35,837 kilometers

Inclination: 16.88 degrees

Delta-v, using https://gtocalc.github.io/, is about 1,616 m/s.
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Offline LouScheffer

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Looking back through this thread, the expectation of the Atlas V 421 DV to GSO, or 4 deg GSO, is incorrect, as the assumption of the SV weight is incorrect.   Additionally, there is the weight of the secondary dispenser and separated payloads.
Yes, from the second post in this thread the reference orbit is a 5.2o inclined GEO orbit.

This means you cannot use the delta-v from https://gtocalc.github.io/, which always assumes a 0 inclination final orbit.  Instead we can do this from first principles:

The targeted transfer orbit, 21.14 degrees, will have a speed at apogee of about 1671 m/s.  Of this, 603 m/s are North-South, and 1559 m/s are East-West.   The target orbit, GEO inclined by 5.2 degrees, has a total speed of 3075 m/s, with a North-South of 279 m/s and and East-West of 3062 m/s.  Therefore the magnitude of the insertion burn is sqrt((603-279)^2+(3062-1559)^2) = 1538 m/s.   This meets the military requirement, which is the injection burn be less than 1594 m/s.

Offline Jansen

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https://www.losangeles.spaceforce.mil/News/Article-Display/Article/2603147/sbirs-geo-5-encapsulated-ahead-of-upcoming-launch/
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The United States Space Force’s Space Based Infrared System (SBIRS) GEO-5 satellite was encapsulated on April 30 at Cape Canaveral Space Force Station (CCSFS) Florida.

The satellite’s encapsulation within the United Launch Alliance's payload fairing represents completion of the final major testing milestone before launch, as well as a key protective measure for the satellite in preparation for its arduous ascent into the earth’s atmosphere.

After encapsulation, GEO-5 was transported to Space Launch Complex-41, where it was mated with an Atlas V rocket. The SBIRS GEO-5 satellite is scheduled for launch on May 17 at 1:35 p.m. EDT.  This is will be the first NSSL launch this year from CCSFS.

Offline Jansen

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https://www.losangeles.spaceforce.mil/News/Article-Display/Article/2602337/multi-manifest-satellite-vehicles-tdo-3-and-tdo-4-ready-for-integration/

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The U.S. Space Force Space and Missile Systems Center’s Launch Enterprise Mission Manifest Office (MMO) delivered two fully tested and integrated multi-manifest satellite vehicles, Technology Demonstration Orbiters (TDO-3 and TDO-4), to Cape Canaveral Space Force Station, for integration aboard the SBIRS GEO-5 mission on May 4.

The MMO is increasing space warfighting domain flexibility by enabling expedited integration and “swap-out” capability of multi-manifest satellites late in the integration process. The SBIRS GEO-5 mission will demonstrate this “swap-out” capability by having two qualified and compatible multi-manifest satellites vehicles ready to be substituted, if needed, as late as two weeks prior to launch. Considering the normal integration timeline for traditional satellites is approximately 24 months, this is just another example of how SMC is driving integration flexibility and responsiveness into the National Security Space planning process and rapidly delivering capability to the warfighter.

TDO-3 and TDO-4, are carrying multiple U.S. Government sponsored payloads that will provide critical experimental data for the United States Air Force Academy (USAFA). The Department of Astronautics at USAFA was the sponsor for TDO-3 and TDO-4. This data will ultimately be used to create capabilities that assist the nation's warfighters in performing their critical missions. The MMO utilized strategic partners National Aeronautics and Space Administration (NASA) Goddard Space Flight Center, NASA/Wallops Flight Facility and numerous industry participants to exercise this urgent effort. The multi-organizational design, analysis, manufacture, test and integration effort was performed within a nine-month period. The successful effort also demonstrated an atmospheric modeling thesis. DNet Engineering & Integration of Denver, Colorado, operated as the bus manufacturer and payload integrator for TDO-3 and TDO-4 satellite vehicles. Parsons Corporation developed the interchangeable EZ Integrated Flight System which was designed to house the TDO-3 and TDO-4 satellite vehicles.

TDO-3 and TDO-4 will deploy into an optimized Geo Transfer Orbit (GTO) after the first upper-stage Main Engine Cut Off (MECO-1) and prior to the SBIRS GEO-5 satellite’s separation. This is the third time that an early separation event has occurred as part of a National Security Space Launch (NSSL) mission. Successfully executing this early separation maximizes the operational utility and flexibility of NSSL and supports the warfighter with added capabilities in space.

The MMO, part of SMC’s Launch Enterprise, is blazing the trail for innovation in the space warfighting domain and continuing the SMC tradition of innovation in space.

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L-4 launch weather forecast is 90% GO

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https://twitter.com/ulalaunch/status/1392928803735932932

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The Launch Readiness Review is complete as preparations continue for Monday's liftoff of #AtlasV carrying #SBIRSGEO5 for the @SpaceForceDoD. The launch window opens at 1:35pmEDT (1735 UTC) and the weather is 90% GO! Follow the mission in our live blog: bit.ly/av_sbirsgeo5

Offline Steven Pietrobon

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The SBIRS satellites do not reduce the inclination all the way to zero, so the delta-V will be less than the calculation used for GEO comsats (that's the 1633 m/s).  It  is left to the interested reader to calculate the delta-V to the 4.3o inclination used by SBIRS GEO-4.

P.S. Here’s the GTO delta-v for SBIRS-GEO 4 upon payload separation (per Spaceflight101.com).

Perigee: 185 kilometers
Apogee: 35,837 kilometers
Inclination: 16.88 degrees
Delta-v, using https://gtocalc.github.io/, is about 1,616 m/s.

I get 1556.3 m/s with an inclination change of 16.88-4.3 = 12.58°.

Enter initial perigee height (km): 185
Enter initial apogee height (km): 35837
Enter required inclination change (deg): 12.58
Enter final orbit height (km): -1
Geosynchronous altitude = 35786.0 km

Burn at 35837.0 km: theta1 = 12.58 deg, dv1 = 1555.4 m/s
Burn at 35786.0 km: theta2 =  0.00 deg, dv2 =    0.9 m/s
dv = 1556.3 m/s

http://www.sworld.com.au/steven/space/gto.zip
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline LouScheffer

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The SBIRS satellites do not reduce the inclination all the way to zero, so the delta-V will be less than the calculation used for GEO comsats (that's the 1633 m/s).  It  is left to the interested reader to calculate the delta-V to the 4.3o inclination used by SBIRS GEO-4.

P.S. Here’s the GTO delta-v for SBIRS-GEO 4 upon payload separation (per Spaceflight101.com).

Perigee: 185 kilometers
Apogee: 35,837 kilometers
Inclination: 16.88 degrees
Delta-v, using https://gtocalc.github.io/, is about 1,616 m/s.

I get 1556.3 m/s with an inclination change of 16.88-4.3 = 12.58°.

Enter initial perigee height (km): 185
Enter initial apogee height (km): 35837
Enter required inclination change (deg): 12.58
Enter final orbit height (km): -1
Geosynchronous altitude = 35786.0 km

Burn at 35837.0 km: theta1 = 12.58 deg, dv1 = 1555.4 m/s
Burn at 35786.0 km: theta2 =  0.00 deg, dv2 =    0.9 m/s
dv = 1556.3 m/s

http://www.sworld.com.au/steven/space/gto.zip
From these various calculations, you can see that removing the last bits of inclination is expensive.  They are roughly
Comsat  (0.0o), starting from SBIRS-4 GTO, 1616 m/s
SBIRS-4 (4.3o), from SBIRS-4 GTO, 1556 m/s
SBIRS-5 (5.2o). from SBIRS-5 GTO, 1538 m/s

That's almost 2 years of stationkeeping fuel, at 50 m/s per year.

Offline ChrisC

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(TFR with map that may be for this launch)

The TFR above implies that the launch will head ENE, just north of due east.  For the low inclination orbits you guys are talking about (e.g. 16 deg, 4 deg, 0 deg, everything less than 28.6 deg) I would expect it to launch due east.  No?

(I'll be in the area and just want to know what to expect)
« Last Edit: 05/14/2021 04:54 pm by ChrisC »
PSA #1: EST does NOT mean "Eastern Time".  Use "Eastern" or "ET" instead, all year round, and avoid this common error.  Google "EST vs EDT".
PSA #2: It's and its: know the difference and quietly impress grammar pedants.  Google "angry flower its" .

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https://twitter.com/torybruno/status/1393246793639645186

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Here’s another #ToryTimelapse for your Friday fun. Vertically integrating our precious cargo. #AtlasV #SBIRSGEO5 #SBIRS

Offline Newton_V

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(TFR with map that may be for this launch)

The TFR above implies that the launch will head ENE, just north of due east.  For the low inclination orbits you guys are talking about (e.g. 16 deg, 4 deg, 0 deg, everything less than 28.6 deg) I would expect it to launch due east.  No?

(I'll be in the area and just want to know what to expect)
Not saying this is for SBIRS......but there are possible other considerations:
1) Maybe require/prefer a specific location of SVSEP
2) Require a specific longitude at apsis, which will be a function of transfer orbit period (perigee alt), but can also be controlled by the longitude of the descending node of the park orbit (flight azimuth)

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https://twitter.com/torybruno/status/1393548367662174215

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Pgo is 90% for cumulus clouds. Rolling to the pad today. #SBIRSGEO5

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https://twitter.com/ulalaunch/status/1393563131079798787

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Welcome to rollout day for ULA's #AtlasV rocket and @SpaceForceDOD's #SBIRSGEO5 missile warning satellite to Space Launch Complex-41 at Cape Canaveral. Liftoff is planned for Monday at 1:35pmEDT (1735 UTC) to add a critical new national asset into orbit. bit.ly/av_sbirsgeo5

Edit to add:

https://twitter.com/ulalaunch/status/1393570136494387212

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ULA Launch Director Steve Huff gives final approval to begin the rollout. Pre-roll preps are complete and the weather is acceptable to move the 194-foot-tall rocket on its Mobile Launch Platform a third-of-a-mile north to the launch pad.
« Last Edit: 05/15/2021 02:14 pm by FutureSpaceTourist »

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https://twitter.com/ulalaunch/status/1393571347779969030

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The #AtlasV rocket rollout is underway from the 30-story Vertical Integration Facility to the Space Launch Complex-41 pad at Cape Canaveral to launch the #SBIRS GEO-5 into Earth orbit on Monday. bit.ly/av_sbirsgeo5

https://twitter.com/ulalaunch/status/1393575023064109056

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The #AtlasV rocket and #SBIRSGEO5 make their way to the pad for Monday afternoon's launch for @SpaceForceDoD and @USSF_SMC: bit.ly/av_sbirsgeo5

Edit to add:

https://twitter.com/ulalaunch/status/1393581741902860290

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#AtlasV has arrived at the pad for Monday's launch of U.S. @SpaceForceDoD's #SBIRSGEO5, the most advanced missile warning satellite ever built. bit.ly/av_sbirsgeo5
« Last Edit: 05/15/2021 03:17 pm by FutureSpaceTourist »

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