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