SpaceX Falcon 9 - Iridium-6 NEXT / Grace-FO

  SpaceX Falcon 9 Block 4 - Iridium-6 NEXT / Grace-FO - Launching May 22, 2018

Screenshot from Webcast of SpaceX Falcon 9 B4 - Iridium-6 NEXT / Grace-FO

Mission Rundown: SpaceX B4 - Iridium-6 - Grace-FO

Written: January 15, 2021

Lift Off Time	May 22, 2018 19:47:58 UTC Universal Time Coordinated May 22, 2018 12:47:58 PDT Pacific Daylight Time
Mission Name	Iridium-6 NEXT Grace-FO
Launch Provider	SpaceX
Customers	Iridium Communications NASA - GFZ German Research Center
Rocket	Falcon 9 Block 4 serial number B1043-2
Launch Location	Space Launch Complex 4 East - SLC 4E Vandenberg Air Force Station, California
Payload	5 Iridium-6 NEXT Communication Satellites 2 Grace-FO Earth Science Satellites
Payload mass	5 x 689 kg ~ 1 519 pounds ~ 4 645 kg total 2 x 600 kg ~ 1 300 pounds ~ 10 195 pounds total
Where are the satellites going?	Polar LEO - Iridium NEXT - 493 km x 712 km x 86.71° Polar LEO - Grace FO - 483 km x 505 km x 88.99°
Will they be attempting to recover the first stage?	No. One way ticket flying “bareback” with no grid fins or landing legs + hydraulic tanks, pumps...
Where will the first stage land?	The Pacific Ocean west of Baja California
Will they be attempting to recover the fairings?	Yes. They are trying to catch one with Mr Steven.
Are these fairings new?	Yes - Type 2 fairings with 8 vent ports doing a double test recovery flight with parachutes
This will be the:	– 55th flight of all Falcon 9 rockets – 12th re-flight of all Falcon 9 boosters – 10th flight of Falcon 9 Block 4 rocket – 3rd re-flight of Falcon 9 Block 4 booster – 10th SpaceX launch from SLC-4E – 33th crash landing soft, hard, deliberate, Ups... – 10th mission for SpaceX in 2018
Where to watch Where to read more	SpaceX link Other:

Launch debriefing (This is what happend)

Host: T-00:14:27 T 00:00:00 T+00:01:23 T+00:02:49 - T+00:02:57 T+00:03:22 T+00:10:17 - T+00:11:39 T+00:56:00 T+00:56:55 - T+01:05:48 - - - -

John Insprucker is behind his desk as per usual SpaceX live feed at 0:32 Liftoff at 15:59 MaxQ at 17:22 (2-3 sec delay on downlink camera) MECO 18:48, stage separation 18:50 0 - 8734 km/h in 169 seconds - altitude 93,3 km SES-1 at 18:56 Fairing  separation at 19:22 SECO at 26:17 - velocity 27 425 km/h - altitude 502 km Grace FO is out of view but a tiny glimpse is spotted Deployment of 2 Grace FO at 27:40 - T+00:11:40 SpaceX resumes live feed at 1:12:00 SES-2 - SECO-2 in 8 seconds gave a velocity boost from 27 433 km/h to 27 581 km/h at 1:12:54 Deployment at 1:21:47 - T+01:07:28 - T+01:09:08 - T+01:10:48 - T+01:12:28 There is 100 seconds between deployments Rap up from SpaceX at 1:28:48 Both fairings landed safely at sea

Bangabandhu-1	Iridium-6 Next Grace-FO	SES-12	CRS-15	Telstar 19 V
Iridium-7 Next	Merah Putih (Telkom-4)	Telstar 18V Apstar-5C	SAOCOM 1A	Es’hail-2

The gravity of the bumpy Earth

SpaceX will launch a flight proven Falcon 9 Full Thrust booster with a Block 5 second stage to put 2 Grace FO earth science satellites and 5 Iridium communication satellites into a low earth polar orbit. These satellites are deployed by a Falcon 9 rocket in a Block 4 configuration.

SpaceX is launching the Iridium-6/GRACE-FO on Tuesday, May 22 from Space Launch Complex 4E (SLC-4E) at Vandenberg Air Force Base, California. The instantaneous launch opportunity is at 12:47:52 p.m. PDT, or 19:47:52​ UTC. The GRACE-FO satellites will be deployed approximately eleven minutes and thirty seconds after launch, followed by the deployment of 5 Iridium® NEXT satellites beginning about an hour after launch.

Falcon 9’s first stage B1043-2 launching the Iridium-6/GRACE-FO mission previously supported the Zuma mission from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station in January 2018. SpaceX will not attempt to recover Falcon 9’s first stage after this launch.

Grace Follow On

The GRACE-FO mission, a collaboration between NASA and GFZ, was launched on 22 May 2018 aboard a SpaceX Falcon 9 rocket from Vandenberg AFB, California, sharing the launch with five Iridium NEXT satellites. During in-orbit checks, an anomaly was discovered in the primary system component of the microwave instrument (MWI), and the system was temporarily powered down on 19 July 2018.

After a full investigation by an anomaly response team at JPL, the backup system in the MWI was powered up on 19 October 2018 and GRACE-FO resumed its in-orbit checks. GRACE-FO entered the science phase of its mission on 28 January 2019.

The orbit and design of GRACE-FO is very similar to its predecessor. GRACE-FO employs the same two-way microwave-ranging link as GRACE, which will allow for similar inter satellite ranging precision. In addition, GRACE-FO employs laser-ranging interferometry (LRI) as a technological experiment in preparation for future satellites.

The two Grace Follow On satellites in tandem flight. Artists impression.

The LRI allows for more accurate inter-satellite ranging due to the shorter wavelength of light, and additionally allows the angle between the two spacecraft to be measured as well as their separation via differential wavefront sensing (DWS). Using the LRI, scientists have improved the precision of the separation distance measurements by a factor of more than 20 relative to the GRACE mission. Each laser on the LRI has about the same power as four laser pointers. These lasers must be detected by a spacecraft about 137 miles (220 km) away. This laser approach will generate much more accurate measurements than the previous GRACE satellite mission.

GRACE-FO will continue to monitor Earth's gravity and climate. The mission will track gravitational changes in global sea levels, glaciers, and ice sheets, as well as large lake and river water levels, and soil moisture. In addition, each of the satellites will use GPS antennas to create at least 200 profiles per day of atmospheric temperature distribution and water vapor content, a first for the GRACE mission.

GRACE-FO has a design life of 5 years.

Iridium-6 NEXT

The 5 Iridium NEXT satellites will be deployed to Orbit Plane 6, where 3 will replace three of the old block 1 Iridium satellites and 2 will replace a couple of old spare satellites. Shortly after deployment, Iridium confirmed successful communication with all five new satellites, formally bringing the total number of Iridium NEXT satellites in orbit to 55. This leaves just two more launches of 10 satellites each to complete this ambitious launch of the Iridium NEXT constellation, featuring 66 interconnected low Earth orbit (LEO) satellites

This will enable never before possible services like the AireonSM global aircraft tracking and surveillance system and its new broadband service, Iridium Certus who will be the world's first truly global broadband service, providing reliable connections for the aviation, maritime, land-mobile and Internet of Things (IoT) related industries, including essential safety services used by first responders world wide.

And while Iridium is already relied upon by governments, non-governmental organizations (NGOs), first responders and a variety of industries worldwide, Iridium Certus will bring users an upgraded infrastructure using Iridium's resilient L-band spectrum, but with higher throughputs and faster speeds.

Iridium's safety services portfolio includes multiple capabilities including aircraft tracking and communications, emergency voice and data communications, personal tracking and remote monitoring applications. Specific to the maritime industry, Iridium has been recognized as the second-ever satellite communications provider for the Global Maritime Distress and Safety System (GMDSS) and plans to begin providing service in early 2020. This is a critical, life-saving service for mariners, and the addition of Iridium will for the first time extend the reach of satellite-enabled GMDSS to even the most remote waterways.

The constellation provides L band data speeds of up to 128 kbit/s to mobile terminals, up to 1.5 Mbit/s to Iridium Pilot marine terminals, and high-speed Ka-band service of up to 8 Mbit/s to fixed/transportable terminals. The NEXT satellites incorporate a secondary payload for Aireon, a space-qualified ADS-B data receiver for use by air traffic control and, via FlightAware, by airlines. A tertiary payload on 58 satellites is a marine AIS ship-tracker receiver for Canadian company ExactEarth. In January 2020, the Iridium constellation was certified for use in the Global Maritime Distress and Safety System (GMDSS).

The fairing recovery

The fairings are equipped with drogue chute mortars, steerable parachutes and a number of cold N2 gas CRS thrusters (6-7), and Mr Steven is deployed on a fairing recovery attempt in the Pacific Ocean. Mr Steven here is equipped with a “small” net between 4 steel posts, and it is no small feat to catch a fairing half the size of a small 34 x 15 foot “boat” hanging in a steerable parachute.

Mr Steven on fairing recovery duty in 2018

A 6 million dollar pair of fairings that can’t get wet is a poor design, but eventually the design changes so saltwater doesn't get in through ventilations ports. Maybe Mr Steven should catch a long fishing line thrown down from the fairing and wheel it in like a big Blue Marlin or Tuna. Hawl it into the net like a paraglider hawled after a boat.

Author Tim Dodd link

Coauthor/Text Retriever Johnny Nielsen link to launch list

SpaceX Falcon 9 - Bangabandhu-1

  SpaceX Falcon 9 Block 5 - Bangabandhu-1 - Launching May 11, 2018

Screenshot from Tim Dodd hosting SpaceX Falcon 9 with Bangabandhu-1 May 10

Mission Rundown: SpaceX Falcon 9 - Bangabandhu-1

Written: January 13, 2021

Lift Off Time	May 11, 2018 - 20:14 UTC - 16:14 EDT
Mission Name	Bangabandhu-1
Launch Provider	SpaceX
Customer	Bangladesh Telecommunication Regulatory Commission US Space Partnership International, LLC
Rocket	Falcon 9 Block 5 serial number B1046-1
Launch Location	Historic Launch Complex 39A - LC-39A NASA’s Kennedy Space Center, Florida.
Payload	Spacebus 4000 Telecommunication Satellite
Payload mass	3 709 kg ~ 8 177  pounds
Where is the satellite going?	Geostationary Transfer Orbit - 308 x 35 549 km x 19.3139°
Will they be attempting to recover the first stage?	Yes - OCISLY have been towed eastward downrange
Where will the first stage land?	On the Autonomous Spaceport Drone Ship - Of Course I Still Love You - located 611 km downrange
Will they be attempting to recover the fairings?	Yes - Go Pursuit were retrieving at least one fairing half
Are these fairings new?	Yes - Type 1 boat hull sized fairings - 34 x 17 feet with 10 evenly spaced ventilation ports in a circle
This will be the:	– 54th flight of all Falcon 9 rockets – 1st flight of Falcon 9 Block 5 rocket – 1st maiden flight of Falcon 9 Block 5 rocket – 14th SpaceX Launch from LC-39A – 25th booster landing overall – 9th mission for SpaceX in 2018
Where to watch Where to read more	SpaceX link May 11, 2018 Other scrubbed Tim Dodd May 10 - It’s informative

Launch debriefing (This is what happend)

- - - T-00:12:27 Hosts: T 00:00:00 T+00:01:16 T+00:02:33 T+00:02:43 T+00:03:32 T+00:06:19 T+00:08:10 T+00:08:24 T+00:27:08 T+00:27:37 - T+00:33:01 T+00:33:41 -

Post Launch Run Down from 0:01 then Q&A until ARGH Tim Dodd does his best, but May 10 launch is scrubbed Sorry Tim I’m going with the SpaceX webcast SpaceX live feed at 5:28 Tom Praderio and Michael Hammersley Liftoff at 17:56 MaxQ at 19:12 MECO 20:30, stage separation 20:32 SES-1 at 20:39 Faring separation at 21:29 Entry burn 24:16 by 3 Merlin 1D# for 26 seconds 10% fuel Landing burn 26:06 by 1 Merlin 1D# for 21 seconds ? SECO at 26:20 and coasting SpaceX resumes live feed at 45:05 SES-2 - SECO-2 in 53 seconds gave a velocity boost from 26 395 km/h to 34 842 km/h at 45:34 SpaceX resumes live feed at 50:58 SpaceX show deployment at 51:37 One fairing lost at sea

PAZ MicroSat 1&2	Hispasat 30W-6	Iridium-5 Next	CRS-14	TESS
Bangabandhu-1	Iridium-6 Next Grace-FO	SES-12	CRS-15	Telstar 19 V

Now we have our workhorse 

SpaceX is targeting the launch of Bangabandhu Satellite-1 on Friday, May 11 from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center, Florida. The two-hour launch window opens at 4:14 p.m. EDT or 20:14​ UTC.

Bangabandhu Satellite-1 will be deployed into a Geostationary Transfer Orbit (GTO) approximately 33 minutes after launch.

The Bangabandhu-1 Satellite mission will be the first to utilize Falcon 9 Block 5, the final substantial upgrade to SpaceX’s Falcon 9 launch vehicle. Falcon 9 Block 5 is designed to be capable of 10 or more flights with very limited refurbishment as SpaceX continues to strive for rapid reusability and extremely high reliability.

Following stage separation, SpaceX will attempt to land Falcon 9’s first stage on the “Of Course I Still Love You” droneship, which will be stationed in the Atlantic Ocean.

The Payload

Screenshot of Bangabandhu 1 in angle test under stress loads

Bangabandhu-1 was designed and manufactured by Thales Alenia Space. It is named after the father of the nation, Bangabandhu Sheikh Mujibur Rahman.

SpaceX will be launching the Bangabandhu 1 telecommunication satellite for the Bangladesh government telecommunication company . The built satellite will ride a Falcon 9 to Geostationary Orbit (GEO).

Bangabandhu 1 is equipped with 14 C-Band and 26 Ku-Band spot beam transponders with a 1600 megahertz capacity. The satellite will expand the Ku-band coverage over all of Bangladesh and its nearby waters including the Bay of Bengal, Nepal, Bhutan, Sri Lanka, the Philippines, eastern Indian states (West Bengal, Assam, Meghalaya, Mizoram, Tripura, Nagaland, Arunachal Pradesh) and Indonesia.

This is coupled with the C-band coverage for all aforementioned areas. It will be able to count holdings as well as to calculate the population density, depending on the natural increase and the natural decrease of birth rates and death rates in a particular country. It scans the number of people per 1,000 km2 with its advanced, installed technology such as cameras. The satellite will be located at an orbital location 119.1° East longitude and provide voice, data and video service to Bangladesh.

SpaceX Falcon 9 Block 5

SpaceX is launching their first "Block 5" rocket out at Launch Pad 39A at Kennedy Space Center, located at Cape Canaveral in Florida. It’s launching Bangladesh's first satellite called Bangabandhu-1, which is pretty small weighing only 3 700 kg. It's heading to a Geostationary Transfer Orbit, so the satellite will have to boost itself into its final orbit. This means the first stage will have to land on the "Of Course I Still Love You" drone ship 611 kilometers down range.

The Falcon 9 per usual stands 70 meters tall now in a black and white colour scheme with the standard 34 foot payload fairing. The black fire resistant legs have been redesigned to retract to avoid demounting the landing legs, but who knows if the legs don't warp during descent making it hard to relock the legs to the boosters locking pins. Spoiler.

This upgraded and "final" block change of the Falcon 9 features a black interstage vacuum engine cover, better and black thermal protection on the first stage for less refurbishment after recovery, black retractable landing legs, slightly increased thrust (8% to 845 kN) and new turbine blades inside the turbo pump in the Merlin 1D# engine. There's other tweaks, but this is the culmination of all landed and reflown Falcon 9 to date!

Another difference between earlier Falcon 9 blocks and Block 5 is a throttle function in the combustion chamber that delivers a constant thrust as the atmospheric pressure reduces, while the rocket ascends above the atmosphere.

The combustion chamber decreases its RP-1/LOX intake, which the earlier Full Thrust Falcon 9 didn’t do, so the combustion chamber pressure isn’t constant aka. “Full Thrust” with the side effect, that the thrust increased 10-15.000 pound-force pr. engine with the reduced air pressure outside the older Merlin 1D+ enginebell.

The only way to reduce thrust and therefore G-force on the payload was to turn the engines down during mach one, just before max Q and stage separation on the old Block 4 and the Full Thrust v1.2. Block 5 no longer needs to do anything other than to throttle down the RP-1/LOX intake of the turbo pumps in the engines to maintain the thrust in decreasing air pressure.

Another new feature is that the RP-1/LOX begins loading at T -35 min, which ensures that the propellant is as cold as can be before liftoff, so that a minimum of LOX gets too “hot” and evaporates away before launch. The LOX is pumped through a liquid nitrogen heat exchanger outside on the launch pad, before it’s pumped into the LOX tanks on the first and second stages of the Falcon 9 rocket.

The LOX tanks are kept chilled by helium bubbles stirring the LOX, giving it more “air” space to evaporate thus removing heat by venting boiled off oxygen through the engines plumbing , which are kept chilled just above working temperature. There are vents at the top of the LOX tanks on the first and second stages, which regularly release the excess pressure in the LOX tanks before liftoff.

But just how big are those LOX tanks?

By utilizing the ratio of LOX to RP-1 is 2,327 part LOX to 1,0 part RP-1 it can be assumed that if LOX density of 1.255 g/cm3 in super chilled condition and with RP-1 chilled density of 0.842 g/cm3, that 2,920 kg LOX + 0,842 kg RP-1 is consumed per second per engine.

3,762 kg propellant x 9 Merlin 1D# engines x 162 second burntime = 5 485 kg propellant.

But with the fact that the 9 Merlin 1D# engines have 410,9 ton of propellant in the first stage fuel tanks. We can now estimate the size of the parts of propellant in the LOX/RP-1 ratio by dividing the 410,9 ton with the 5,485 ton which gives 74,91 as the number of portions of propellant that a Merlin 1D# engine consumes. Is that the nozzle size?

74,91 x 3,762 kg propellant x 9 Merlin 1D# x 162 second = 410 900 kg propellant.

I have calculated the minimum tank volume in the first stage on both types of propellants by multiplying with the number of engines and the total burn time. 174,29 liter x 9 Merlin 1D# engines x 162 seconds burn time = 254 118 liter equivalent to 254,12 m3 of LOX tank space in the first stage. 74,91 liter x 9 Merlin 1D# engines x 162 seconds burn time = 109 219 liter equivalent to 109,22 m3 of RP-1 tank space in the first stage.

With 2 242,8 liters of propellant is consumed by the 9 Merlin 1D# engines every second of full thrust during liftoff. This is equivalent to 592,5 gallons of propellants to those metric impared. It can also be calculated as kilograms per liter using the LOX/RP-1 densities. 

218,73 kg x 9 Merlin 1D# engines x 162 seconds burn time = 318 908,34 kilogram LOX.

63,07 kilo x 9 Merlin 1D# engines x 162 seconds burn time = 91 956,06 kilogram RP-1.

These calculations are minimum numbers on the first stage only, I have yet to do a more precise calculation on the second stage. There should be extra room for evaporation in the top tank dome and room for a number of COPV helium and nitrogen tanks.

An extra engine chilling makes sure that the LOX doesn't boil off immediately in a thermal shock on the metal engine parts, and because the Merlin 1D# engines prefer liquid oxygen pumped directly into the pressure chamber with cold -70 Celcius RP-1 before combustion and rocket thrust build up.

Falcon 9 Block 5 will be ready for NASA to certify it for human transport from American soil, but it must prove itself first through its reliability. That means the COPV Composite Overwrapped Pressure Vessel model 2.0 should fly at least 7 times without incidents before being certified by NASA. From booster B1047 they will be a standard fixture on the Falcon 9 Block 5 rockets.

This booster B1046 is equipped with the last old COPV model 1.0 and it was used later on in a spectacular in-flight abort test of the new Dragon 2 or Crew Dragon. Spoiler alert.

I have used the Scandinavian unit “km/t kilometer i timen” which should be kilometers pr. hour in english speaking countries. I’m sorry. It's been corrected by now.

Author: Tim Dodd and SpaceX link

Coauthor/Text Retriever: Johnny Nielsen link to launch list