SpaceX Falcon Heavy 3 - STP-2

  SpaceX Falcon Heavy FH 3 - STP-2 - Launching June 25, 2019

Falcon Heavy preparing to mate with fairing in SpaceX’s hangar at LC-39A → spacex.com/stp-2 If anyone asks, I’m just hangin out before my flight and waiting for the TEL to come pick us up

Mission Rundown: SpaceX Falcon Heavy - STP-2

Written: January 6, 2021

Lift Off Time	June 25, 2019 - 06:30 UTC - 02:30 EDT
Mission Name	STP-2 - Space Test Program 2
Launch Provider	SpaceX
Customers	U.S. Department of Defense NASA NOAA
Launch Vehicles	Left Block 5 side booster B1052-2 Y- Falcon Heavy Block 5 Core Booster B1057 Right Block 5 side booster B1053-2 Y+
Launch Location	Historic Launch Complex 39A - LC-39A Kennedy Space Center at Cape Canaveral, Florida
Payload	12 Mini- Nano- & Microsatellites 12 CubeSats from various sources
Payload mass	3 700 kg ~ 8 157 pounds
Where are the satellites going?	The satellites will be deployed in 3 distinct orbits, 2 Low Earth Orbits and the DSX spacecraft will be deployed in a Medium Earth Orbit.
Will they attempt to recover the first stage and side boosters?	Yes - The side boosters have enough fuel to return to launchsite - The core booster is aiming for OCISLY.
Where will the first stage and boosters land?	On OCISLY 1 236 km (771 miles) down range and Landing Zones LZ-1 & LZ-2 at CCAFS
Will they be attempting to recover the fairings?	Yes - GO Navigator and GO Ms Tree will be participating in fairing catch attempt 1 346 km downrange
Are these fairings new?	Yes - Type 2.2 lifeboat sized fairings - 34 x 17 feet with 8 ventilation ports and a heat resisting steel tip
This will be the: Falcon Heavy is not a single stick launch vehicle so in order to reduce confusion only their single boosters are counted as Falcon 9’s regarding their landings The Falcon Heavy core booster didn't make it to OCISLY 1236 km downrange	– 3rd Falcon Heavy launch by SpaceX – 1st flight of Falcon Heavy core booster – 1st & 2nd re-flight of Falcon Heavy sidebooster – 18th SpaceX launch from LC-39A – 41st, 42nd & 43rd booster landings overall – 39th crash landing. soft, hard, deliberate, Ups... – 8th mission for SpaceX in 2019
Where to watch Where to read more in depth	SpaceX link Tim Dodd on Falcon Heavy 3 June 25, 2019

Launch debriefing (This is what happend)

- T-00:19:17 Hosts: T 00:00:00 T+00:00:48 T+00:02:33 T+00:02:52 T+00:03:34 T+00:03:43 T+00:04:08 T+00:07:18 T+00:08:22 T+00:08:45 T+00:09:40 T+00:11:10 T+00:13:06 - - - T+01:12:40 - T+01:13:51 - T+01:19:30 - - - - - T+02:06:58 T+02:07:42 - T+03:27:01 T+03:27:28 - T+03:34:22 T+03:35:53

Pre Launch Run Down from 3:15 then Q&A SpaceX live feed at 14:06 Alex Siegel, Jessica Andersson and John Insprucker  Liftoff at 33:27 - 06:30:00 UTC MaxQ at 34:15 (3 sec delay on downlink camera) BECO at 36:02 Booster release at 36:05 Boost back burn by boosters at 36:21 - 67 seconds MECO 37:03, stage separation 37:05 SES-1 at 37:12 Fairing separation at 37:37 Booster entry burn 40:48 by 6 Merlin 1D# for 20 seconds Landing burn 41:52 by 2 Merlin 1D# for 22 seconds SECO-1 at 42:15 and coasting Entry burn 43:10 by center core for 14 seconds Landing burn 44:40 by center core - failed Deployment 1 at 46:36 - T+19:23 - T+24:59 - T+28:52 - T+31:18 - T+34:05 - T+38:50 - T+43:54 - T+50:10 Replays, tweeting with Q&A between deployments and launch day offer merchandise at 1:27:40 SES-2 - SECO-2 gave a velocity boost from 25.070 km/h to 25.280 km/h in 22 seconds First fairing half caught by GO Ms. Tree 1:47:27 - The other half was damaged but salvaged Deployment 2 at 1:53:03 - T+01:21:54 - T+01:24:05 - T+01:27:13 - T+01:31:23 - T+01:34:36 - T+01:36:30 - T+01:39:53 - T+01:43:20 - T+01:46:13 Q&A with info, explanations from 2:19:10 Launch day offer on merchandise at 2:23:35 Rap up from Tim Dodd at 2:24:11 And watching SpaceX from 02:31:56 their video time SES-3 and SECO-3 gave a velocity boost from 25.352 km/h to 28.837 km/h in 30 seconds, apogee 6 000 km SpaceX is back for final MEO burn and deployment SES-4 and SECO-4 gave a velocity boost from 14.630 km/h to 20.046 km/h in 47 seconds, altitude 6.006 km Deployment of DSX at 1:53:03 Hats of to Tim Dodd

DM-1	FH-2 Arabsat-6A	CRS-17	Starlink V0.9 L0	RADARSAT
FH-3 - STP-2	CRS-18	Amos-17	Starlink V1.0 L1	CRS-19

One giant leap for… - …was just too far

SpaceX will be launching the Space Test Program 2 (STP-2) rideshare mission for the U.S. Air Force’s Space and Missile Systems Center on a Falcon Heavy rocket. This Falcon Heavy is composed of a new block 5 center core (B1057) and the two block 5 side boosters (B1052-2 & B1053-2) from the Arabsat-6A mission.

The launch window for this mission opens at 11:30 PM EDT on June 24, 2019 and is 4 hours in duration. The Falcon Heavy will be lifting off from Launch Complex 39A (LC-39A) at the Kennedy Space Center in Florida. After burning for about 2 and a half minutes, the side boosters will separate from the core booster and boost back to the launch site for a landing at Landing Zones 1 & 2 (LZ-1 & LZ-2).

The core booster will continue burning for another minute, before shutting down and separating from the second stage. The core booster will be landing approximately 1 239 km (771 miles) downrange on the Autonomous Spaceport Drone Ship, Of Course I Still Love You (OCISLY). The core booster crash landed and did not survive the impact.

Screenshot of Falcon Heavy mission view by Geoff Barret - The soddy side boosters have flown before

It took 8 months to make a deployment list

The unclear Payload

From Wikipedia it says that the STP-2 (DoD Space Test Program) payload was launched aboard a SpaceX Falcon Heavy on 25 June 2019 - 06:30:00 UTC.

Included was COSMIC-2, a cluster of six satellites, with a mass of 277,8 kg each. The primary role of the COSMIC-2 satellite constellation is to provide radio occultation data with an average latency of 45 minutes.

The six satellites were placed on an orbit with an inclination of 24 to 28.5 degrees with plans for them to move eventually to six separate orbital planes with 60 degree separation between them. The payload stack was integrated using an ESPA ring. Two ESPA Grande adapter rings were used to mount the six COSMIC-2 satellites beneath the upper payload adapter hosting the DSX payload and avionics modules. Arrgh Write it properly ESPA ring.

STP-2 also deployed a number of CubeSats as secondary payloads, including E-TBEx, PSAT, TEPCE, and 3 ELaNa 15 CubeSats. LightSail 2 is carried by the Prox-1 nanosatellite. Other satellites and payloads included Oculus-ASR nanosatellite, GPIM, and the Deep Space Atomic Clock. Another source of information is this article.

LightSail 2 after a boom deployment test

Screenshot of artist impression of STP-2 payload mounted on ESPA rings with portholes

There are 4 ESPA rings with 17 ports upon which a Minisatellite or CubeSat dispenser is secured. PPOD 1-8 deploys the first 11 CubeSat payloads.

Payload Pay Dirt

From the eo Portal Directory this article about the Deep Space Atomic Clock shows the precise loading manifest of STP-2, so now there is access to a more detailed Payload list, and an educational explanation of the use of atomic clocks in space.

First set of deployments consists of 10 small secondary CubeSat satellites that will be deployed into an elliptical orbit of ~300 x 860 km, inclination of ~28º.

OCULUS-ASR deployed from ESPA ring 1 port 1 of 5 in top view of PAF camera

OCULUS-ASR: Attitude and Shape Recognition Microsatellite - 70 kg - from MTU

OCULUS-ASR SPHERE: Deployed Attitude and Shape Recognition CubeSat- 2 kg - MTU

PPOD-1 have deployed DOTSI an unlisted CubeSat along with TEPCE

TEPCE 1&2: Tether Electrodynamics Propulsion CubeSat Experiment, a 3U CubeSat 3 kg

PPOD-2 have deployed FalconSat-7

FalconSat-7: a 3U CubeSat mission developed by the Cadets of the U.S. Air Force Academy

PPOD-3 have deployed ARMADILLO

ARMADILLO: a nanosatellite - 3U CubeSat from University of Texas at Austin, mass ~ 4 kg

PPOD-4 have deployed PSAT-2 and BricSat 2

PSAT-2: ParkinsonSAT, a student built 1.5U CubeSat of US Naval Academy - mass 2 kg

BRICSAT: a student built a 1.5U CubeSat of USNA (US Naval Academy) to demonstrate a µCAT 

electric propulsion system and carry a ham radio payload

PPOD-5 have deployed the Prometheus CubeSat, another unlisted CubeSat

PPOD-6 have deployed E-TBEx A, the first of the tandem pair of CubeSats

E-TBEx A: Enhanced Tandem Beacon Experiment, a 3U CubeSats from SRI

PPOD-7 has deployed E-TBEx B, the second of the tandem pair of CubeSats

E-TBEx B: Enhanced Tandem Beacon Experiment, a 3U CubeSats from SRI

PPOD-8 has deployed CubeSats CP-9 “LEO” and StangSat

CP-9/StangSat: a joint 2U CubeSat/1U CubeSat experiment sponsored by NASA LSP

By seeing CP-9 “LEO” deployed, I suspect that PPOD 1-8 is a CubeSat dispenser mounted on top of DSX, which is mounted on ESPA ring 4 port 1 or Z+ who is in camera view.

The last set of CubeSat are developed under the ELaNa-15 program - Educational Launch of Nanosatellites run by the Launch Services Program (LSP) at NASA's Kennedy Space Center in Florida.

Second sets of deployments consist of 10 Mini- and Nanosatellites and 1 CubeSat, which will be deployed in a circular orbit at 720 km altitude and at an inclination of 24º.

Prox-1: Nanosatellite - mass 71 kg - Space Systems Design Laboratory at Georgia Tech

LightSail-2: Planetary Society, Nanosatellite 3U CubeSat - mass 5 kg - are deployed by Prox-1 who were deployed from ESPA ring 1 port ? of 5 out of view of PAF camera

NPSat-1: Nanosatellite - mass 86 kg from Naval Postgraduate School, Monterey, CA.

NPSat-1 where deployed from ESPA ring 1 port 2 of 5 in view of PAF camera

OTB-1: Minisatellite with NASA's DSAC - Deep Space Atomic Clock - millimeter accuracy?

OTB-1 where deployed from ESPA ring 1 port ? of 5 out of view of PAF camera

GPIM: Green Propellant Infusion Mission Minisatellite - hydroxylammonium nitrate (HAN)

GPIM  where deployed from ESPA ring 1 port ? of 5 out of view of PAF camera

6 FormoSat-7/COSMIC-2 Satellites on ESPA ring 2 and 3 from NOAA and Taiwan’s NSO

COSMIC-2-5 deployed from ESPA ring 2 port Z+ who are in view of PAF camera

COSMIC-2-6 deployed from ESPA ring 2 port Z- who are out of view

COSMIC-2-2 deployed from ESPA ring 2 port Y- who are out of view

COSMIC-2-4 deployed from ESPA ring 2 port Y+ who are in view

COSMIC-2-1 deployed from ESPA ring 3 port Z- who are out of view

COSMIC-2-3 deployed from ESPA ring 3 port Z+ who are in view

Third and last deployment happens after two orbit raising and circulation burns made by the second stage to reach an elliptical MEO (Medium Earth Orbit) with a perigee of 6000 km and an apogee of 12000 km, inclination of 43º.

DSX: Demonstration and Science Experiments mission of AFRL Air Force Research Lab

SET 1 and 2 are DSX payload and avionics mounted on ESPA ring 4 port 1 and 3; Z+ and Z-

DSX payload where deployed with ESPA ring 4 mounted on port 1 Z+  in view of PAF camera

There is no longer something missing in this launch manifest. After searching 6 different sources, it’s now possible to find a more clear loading manifest and details about the 24 Minisatellites and CubeSats and their deployment order.

Other multi-satellite deployments have the same problem with being superficial. Only details about the CubeSats are lacking “Sorry. Nerd level 9 in progress.”

In the picture below, there are a pair of missing payloads called SET-1 and SET-2, which will replace the two Van Allen Probes. The Space Environment Testbed payloads should have had a recognizable mission name, but damn if I know which payload. Maybe there was room for two extra Minisatellites, but they got cut from the loading manifest.

Found them at last. It’s DSX on ESPA ring 4. Enjoy the picture. It’s at least “colorful”.

The missing payloads is SET-1 and 2, who will replace the two Van Allen Probes - It’s DTX Arrgh

Following orbital targets were identified by the NORAD space track. “Sorry. Nerd level 10.”

NORAD  Name               NSSC ID    Type  Country Period Incl.   Apo  Peri

44339  Prox-1             2019-036A  NanoSat TBD   99.13  24.00   725   709

44340  NPSat1             2019-036B  NanoSat TBD   99.12  24.00   725   708

44341  OTB-1              2019-036C  MiniSat TBD   99.12  24.00   725   708

44342  GPIM               2019-036D  MiniSat US    99.09  24.00   725   706

44343  Formosat/Cosmic-3  2019-036E  PAYLOAD TBD   99.10  24.00   725   707

44344  DSX                2019-036F  PAYLOAD US   316.92  42.21 12035  6005

44345  FH R/B 2nd stage   2019-036G  Debris  US   306.86  42.24 11936  5449

44346  OBJECT H           2019-036H  TBA     US    96.27  28.52   853   307

44347  OBJECT J           2019-036J  TBA     US    96.24  28.53   850   307

44348  OBJECT K           2019-036K  TBA     US    96.23  28.52   852   304

44349  Formosat/Cosmic-1  2019-036L  PAYLOAD TBD   99.10  24.00   724   707

44350  Formosat/Cosmic-4  2019-036M  PAYLOAD TBD   99.10  24.00   724   707

44351  Formosat/Cosmic-2  2019-036N  PAYLOAD TBD   99.09  24.00   724   706

44352  ARMADILLO          2019-036P  CubeSat       96.21  28.54   848   306

44353  Formosat/Cosmic-6  2019-036Q  PAYLOAD TBD   99.09  24.00   724   706

44354  PSat-2             2019-036R  CubeSat US    96.19  28.53   847   305

44355  BricSat-2          2019-036S  CubeSat US    96.19  28.53   847   305

44356  OCULUS ASR         2019-036T  NanoSat       96.15  28.52   847   301

44358  Formosat/Cosmic-5  2019-036V  PAYLOAD US    99.09  24.00   725   705

44359  E-TBEX-B           2019-036W  CubeSat US    96.14  28.52   847   300

44360  CP-9 LEO           2019-036X  CubeSat       96.06  28.52   842   298

44361  E-TBEx A  OBJ Y     2019-036Y  guess   US    96.12  28.52   848   297

44375  OBJECT Z           2019-036Z  TBA           96.17  28.52   845   306

44376  OCULUS-ASR SPHERE1 2019-036AA CubeSat       95.91  28.51   820   305

44386  PROMETHEUS 2-6     2019-036AB CubeSat       96.15  28.53   844   304

44386  Lightsail          2019-036AC CubeSat       96.15  28.53   844   304

Five to go:  E-TBEx A, FalconSat7, StangSat, TEPCE 1&2 as Object H, J, K, Y & Z.

After the last deployment there will not be enough propellant in the second stage tanks to deorbit, so this third Falcon Heavy launch will produce yet another large piece of space debris that will take a long time to deorbit on its own.

Maybe the 2nd stage should be equipped with a passive payload packet from NASA so it can do a bit of science. It is kind of a satellite bus, it’s missing solar panels for power, gyroscopes for orientation, solarwind detectors, magnetic field instruments and Hall effect thrusters to deorbit itself with. There are some possibilities in a NASA science packet.

Mirror Mirror on the… Deck

At 2:00:46 (T+01:27:13) you see the reflection of the GPIM satellite deployed in the upper left corner of the screen. That’s a rare sight to behold. 

The Center Core was aiming directly at the Drone Ship, but something made it tip over, and it bolted and sped off and flew itself directly in the ocean just off the OCISLY starboard forward side, almost missing it. The light from the triple engine burn is reflected off the back blast shield, so it was almost working perfectly.

Just before landing, the water on the deck was blasted away, so it was on target, but an engine lost thrust so the others opened up uncontrolled to get away from OCISLY.

Author John Rumpf - former member of the Everyday Astronaut team - link

Coauthor/Text Retriever Johnny Nielsen link to launch list

SpaceX Falcon 9 - RadarSat

  SpaceX Falcon 9 Block 5 - RadarSat - Launching June 12, 2019

Screenshot of Tim Dodd: SpaceX launch Falcon 9 through the fog with RadarSat - WOW

Mission Rundown: SpaceX Falcon 9 B5 - RadarSat

Written: January 5, 2021

Lift Off Time	June 12, 2019 - 14:17 UTC Universal Time Coordinated June 12, 2019 - 07:17 PDT Pacific Daylight Time
Mission Name	RadarSat
Launch Provider	SpaceX
Customer	Canadian Space Agency (CSA)
Rocket	Falcon 9 Block 5 serial number 1051-2
Launch Location	Space Launch Complex 4E - SLC-4E at the Vandenberg Air Force Base (VAFB).
Payload	3 MDA Earth Observation Radar Satellites
Payload mass	4 290 kg ~ 9 458 pounds
Where will the satellites go?	Low Earth Sun Synchronous Orbit - 592 km x 97.74°
Will they be attempting to recover the first stage?	Yes - There is fuel enough to return home
Where will the first stage land?	LZ-4 west at Vandenberg Air Force Station
Will they be attempting to recover the fairings?	No - Type 1 fairings are no longer being produced
Are these fairings new?	Hmm - Old Type 1 boat hull sized fairings - 34 x 17 feet with 10 evenly spaced ventilation ports in a circle
This will be the:	– 72th flight of all Falcon 9 rockets – 22th re-flight of all Falcon 9 boosters – 16th flight of Falcon 9 Block 5 rocket – 8th re-flight of Falcon 9 Block 5 booster – 15th SpaceX launch from SLC-4E – 40th booster landing overall  – 7th mission for SpaceX in 2019
Where to watch Where to read more in depth	SpaceX link Other Tim Dodd on RadarSat June 10, 2019

Launch debriefing (This is what happend)

- - T-00:12:07 Host: T 00:00:00 T+00:01:07 T+00:02:18 T+00:02:26 T+00:02:39 T+00:02:55 T+00:06:12 T+00:07:22 T+00:08:34 - - - T+00:50:13 - T+00:54:49 - - - -

Pre Launch Run Down from 3:05 then Q&A Tim Dodd talks about a video on Raptor Engines SpaceX live feed at 22:37 Kate Tice was all alone today Liftoff through the fog at 34:45 MaxQ at 35:52 (3 sec delay on downlink camera) MECO 37:03, stage separation 37:05 SES-1 at 37:11 Boost back burn at 37:24 for 40 seconds Fairing  separation at 37:40 Entry burn 40:57 by 3 Merlin 1D# for 23  seconds Landing burn 42:07 by 1 Merlin 1D# for 34 seconds SECO at 43:19 and coasting Q&A with info, replays and explanations from 43:57 Launch day offer on merchandise 55:12 Q&A Kerbal until live feed resumes at 1:23:45 SES-2 - SECO-2 gave a velocity boost from 27 060 km/h to 27 488 km/h in 5 seconds Deployment at 1:29:33 - T+00:58:29 - T+01:02:21 Q&A with info, replay and explanations from 1:38:00 Launch day offer on merchandise at 1:46:12 Rap up from Tim Dodd at 1:48:50 Both fairings lost at sea

DM-1	FH-2 Arabsat-6A	CRS-17	Starlink V0.9 L0	RADARSAT
FH-3 - STP-2	CRS-18	Amos-17	Starlink V1.0 L1	CRS-19

: Screenshot from Tim Dodd: SpaceX RadarSat Overview by Geoff Barrett

Three brothers left to see the World

SpaceX will be launching the RADARSAT constellation of 3 satellite vehicles for the Canadian Space Agency (CSA) on a Falcon 9 rocket from Space Launch Complex 4E - SLC-4E at the Vandenberg Air Force Base (VAFB).

The three satellites were launched on 12 June 2019 at 14:17 UTC on board a Falcon 9 rocket, who’s regular Payload Adaptor Fitting was equipped with a three clover adaptor, on which the three RadarSats were mounted on release clamps.

This booster, B1051, is flying for the second time. It previously boosted the DM-1 Crew Dragon capsule to orbit in March 2019. No recovery of the type 1 fairings.

SpaceX DM-1

March 2, 2019

RADARSAT

June 12, 2019

The Three Clover Payload

The constellation consists of three identical satellites built by MacDonald, Dettwiler and Associates ltd. (MDA). Each satellite weighs 1 430 kg (3 153 pounds). The instruments onboard are a C-Band synthetic aperture radar and an Automatic Identification System. The objectives of the satellites are to perform maritime surveillance, with ship detection, ice monitoring, oil pollution monitoring and maritime wind measurement, as well as disaster management and environmental monitoring.

The satellites will fly in a Sun synchronous low Earth orbit at an altitude of approximately 600 km (373 miles), at an inclination of 97.74 degrees and an orbit taking ~ 96 minutes. 

Screenshot of the RadarSat satellite. Credit: Canadian Space Agency.

This is the third RadarSat mission for CSA. RadarSat-1 was launched on a Delta II on November 4, 1995 ending its mission on March 29, 2013. RadarSat-2 was launched on a Soyuz-FG Fregat rocket on December 14, 2007 and is still active.

Originally booster B1050 was planned to be used for this mission. However, after the failed landing of B1050, booster B1051 was moved up to be used in this mission.

Three Merlins? That’s a good question

Liquid Chris: Why does SpaceX use three Merlin 1D# rocket engines during reentry?

When you fall, you accelerate by 1 g aka. 9,82 m/s2. Multiplied by your weight “mass”, you get the Force -1 N pr. kilo weight. To stop that you need +1 N pr. kilo weight just to hover or maintain your current falling speed, but you need to break. If you don’t, Earth will stop you dead in an instant. Just ask SN8 and SN9.

A descending Falcon 9 booster weighing 20-25 ton dry + x tons of propellant traveling 4-5 times faster than a bullet needs a lot of thrust to break midair without crumbling itself like an empty Beer Can. So the +G force must not exceed 3,5 G.

This booster B1051-2 had an entry burn at 40:57 by 3 Merlin 1D# for 23 seconds, and they lit up in a one - three - one sekvens, each sekvens taking 4 seconds, 19 seconds and 2 seconds. How they were throttled on the entry burn is unknown, but each Merlin 1D# rocket engine has a 845 kN - 482 kN thrust range.

They have a max. thrust of + 2 535 kN to counter a - 400 kN (I’m guessing double dry weight) speeding down towards earth, but that's a thrust to weight ratio of 6,3, which is too much. A rocket hull is like a beer can, it will crumble and disintegrate. At minimum thrust of 1 446 kN reduces the thrust to weight ratio to 3,6, which is structurally survivable.

B1051-2 had an available burn time of 9 x 162 seconds and used 9 x 140 seconds on the accent burn, 1-3-1 x 40 seconds on boost back burn, 1-3-1 x 23 seconds on entry burn and 1 x 34 seconds on the landing burn. 162 - 140 = 22 second burntime left, or 66 seconds burntime for 3 Merlin 1D#, so 66 - 40 = 26 second burntime left. The entry burn used 23 seconds so there is now only 3 seconds left, or 9 seconds by one engine, even that's not enough for the 34 second landing burn.

Now here's the throttle to the rescue. A low “idle” thrust burn takes longer than a full thrust burn, because it has a lesser fuel consumption. 482 kN is 57% of 845 kN and must use 57% less propellant, so 23 seconds at 57% thrust is equivalent to a 13,1 second 100% burn time. Now there is 10 plus 9 second full thrust burn time left for the landing burn.

19 seconds full thrust landing burn or with 57% “idle” thrust in 33,33 seconds which is almost enough to make the 34 second landing burn.

Now the throttle has been used several times during the flight before the entry burn, and the throttle hasn't been either full up or only at “idle” at 57%. That means, the fuel consumption has been less during throttle down periods, so the remaining burn time increases by the throttle down usages and throttle percentages.

Now a genuine rocket scientist can tweak these thrust numbers to such a degree, that the booster lands on fumes or at least 100 kilo propellant left in the tanks.

That should “sort of” answer the 3 engine reentry burn question. - Rocket Mechanic -

This needs more work... Decent speed km/h? Delta V? Energy content m x V2 ? The variable propellant weight? Oh Man… My head hurts… Doctor… DOCTOR... WHO

Now some three months later I found a minor nugget. This will help with this question. The green throttle curve is slowly building up G-forces. Each spike down is a throttling down with less and less propellant intake and usage in the Merlin 1D# engines. There is data for both stages during ascent.

‘There’s Gold in them there Hills.’ John Houston. Movie actor.

Author: Trevor Sesnic Spaceflight entusiast link

Coauthor/Text Retriever: Johnny Nielsen link to launch list