After Months of Preparations Starship is Ready for Flight 3

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Starship Flight 3 is set and ready to fly after months of preparations and SpaceX learning from the issues encountered during Flight 2. Booster 10 and Ship 28 are the most advanced pair of vehicles yet to be slated for an integrated test flight of Starship.

The launch of the world’s most powerful rocket is set for 7 a.m. local time from Starbase in Texas.

Flight 1

SpaceX will be aiming to continue its impressive improvements over the past two flights, which opened with Starship Flight 1.

Booster 7 and Ship 24, which at the time weren’t the best vehicles available, were mainly tasked with simply clearing the pad and gain some flight ascent data.

Right at liftoff, three engines were already out, resulting in a slow liftoff and massive damage to the launch pad. The stack didn’t make it very far in flight, with more and more engines cutting out during flights due to fires in Booster 7’s engine bay. This resulted in both vehicles’ eventual loss before stage separation.

Even though Flight 1 had a lot of issues, those were valuable lessons learned for the program at large.

Starship’s Maiden Flight (Credit Max Evans for NSF).

After this flight, SpaceX went to work repairing the Orbital Launch Pad (OLP), adding a water deluge flame deflector plate to prevent pad damage going forward. Then, on the booster, SpaceX would increase the capability of the onboard fire suppression system for the engine bay. These two upgrades would help immensely during Flight 2.

Flight 2

Then came Flight 2, where SpaceX used Ship 25 with Booster 9.

Ship 25 sported some additional modifications compared to Ship 24, such as an upgraded Flight Termination System (FTS), strengthened engine shielding, and vents above the engine shielding.

Booster 9 had some significant upgrades compared to Booster 7 for example, better engine shielding, more vents for better tank control, upgraded raptors with Electric Thrust Vector Control (TVC), an upgraded fire suppression system for the engine, and last but not least, a hot staging ring.

The upgrades to the engine section and the engines themselves would help prevent fires and explosions from occurring during flight, allowing Booster 9 to complete its accent with all 33 engines running.

Starship Flight 2 (Credit: Max Evans for NSF)

However, Booster 9 would not make it past boost back burn, as an engine exploded, ultimately leading to the loss of the booster.

Ship 25 almost made it to orbital velocity with the FTS being activated due to fires on board and wiring being destroyed, which led to communications being lost to the flight computer. In terms of the OLP improvements, the new foundation and water deluge plate worked perfectly with the pad looking far better than after Flight 1.

Flight 2 – with its modifications and successful debut of hot staging – would set the stage for what is hoped to be the first fully completed orbital flight test for Flight 3.

Flight 3

Currently, SpaceX is targeting no earlier than March 14 for Flight 3 of Starship, with Ship 28 and Booster 10 being the stars this time. The Federal Aviation Administration (FAA) has issued the modification to Starship’s launch license.

This license is again only for this flight, Flight 3. Another addition to the license mentions the landing zone change for Starship to the Indian Ocean rather than Hawaii.

SpaceX and the FAA had to perform an environmental assessment for the new landing zone in the Indian Ocean, and SpaceX was approved for ten launches.

Here are a few quotes from the Environmental Assessment: “Based on the information SpaceX has provided to the FAA to date, it is reasonably foreseeable to analyze the potential for up to a total of ten nominal operations, including up to a maximum of five overpressure events from Starship intact impact and up to a total of five reentry debris or soft water landings in the Indian Ocean, within a year of issuance of a NMFS concurrence letter.”

As well as: “SpaceX has a near term goal of soft water landings by the end of 2024 and the ultimate goal of
landing the Starship vehicle on land/barges to ensure reusability of the vehicle, however a high degree of uncertainty
remains for the timing of successful missions to accomplish that goal. There are also potential vehicle changes that could
affect future impact analyses. This is similar to SpaceX’s prior development of the Falcon vehicle.”

With these statements and the Environmental Assessment completion, SpaceX was able to issue the modification to the Starship Launch License

However, it is important to note that the weather for March 14 is something to watch closely. There is a possibility of moderate wind shear, which could delay the launch if it is not within bounds for Starship.

Per the road closures, windows are set for March 14, 15, and 16 that run 12 am – 2 pm CDT.  The current launch windows on March 14 and 15 are set for 7 am – 9 am CDT, and then on March 16, the window is around 30 minutes. And, the Notice to Air Missions (NOTAM) runs from March 14 to 18, indicating that SpaceX has backup opportunities for Sunday and Monday as well, should it be needed. 

Ship 28 was stacked on Booster 10 on the morning of March 10 with the flight termination system installed. Crews continued to perform final checkouts with retract tests of the booster and ship quick disconnects, as well as another test with the water deluge plate.

Vehicle Changes for Flight 3

Flight 3 has a few upgrades over Booster 9 and Ship 25, but fewer than between Flight 1 and 2. However, the Orbital Tank Farm has many upgrades.

In terms of vehicle changes, Booster 10 has one major change: its common dome is now the simpler elliptical dome that has been seen in test tanks in the past. The only other difference is the addition of what appear to be new large slosh baffles at the bottom of the Liquid Oxygen (LOX) Tank. These could help counteract the propellant sloshing that occurs during the flip and boost back burn.

Ship 28 on Pad B (Credit: Mary (@bocachicagal) For NSF)

Ship 28’s changes include more refinements and some structural reinforcement. First, the header tank vents have some nice cowbells to help redirect the gasses down and away from the heat shield. SpaceX has deleted three LOX tank vents, two cowbell vents, and one of the side vents. 

In addition to vent changes, Ship 28’s LOX tank added vertical stringers for structural reinforcement. There are also larger doubler plates on the aft dome weld line, these reinforcements were introduced on Ship 26.

Launch Pad Changes

In terms of the launch pad, SpaceX added four LOX subcoolers and two pumps, then two Liquid Methane (LCH4) subcoolers and one pump to the propellant. With these additions, SpaceX was able to reduce its propellant loading time from 97 minutes, as with the previous two flights, to 50 minutes with this flight. 

Upgraded LOX Side of OTF with new Blast Wall (Credit: Sean Doherty for NSF)

As part of these added subcoolers and pumps, SpaceX split up the ones for the ship and booster. The booster now has six LOX and three LCH4 subcoolers, and the ship has two LOX and one LCH4 subcooler.

Another large change was the addition of detank manifolds on both the LOX and LCH4 sides of the tank farm allowing SpaceX to be able to detank the vehicle faster during testing or in an abort scenario. This also reduces the turnaround time between launch attempts as teams can recover more of the propellant.

Launch Timeline

As mentioned above, the propellant load for Flight 3 will be much faster than that of previous flights. For Flight 3, the GO call for propellant load is at T-1 hour and 15 minutes, compared to Flight 2, where the call was at T-2 hours.

One of the biggest changes to the timeline is that the propellant load for the Ship will start 11 minutes before the booster propellant load, whereas for Flight 2, Ship load starts 20 minutes after the booster propellant load. A reason why the Ship is loaded first now could be that with the new tank farm setup, teams can have both vehicles finish propellant load at nearly the same time.

A couple of new things stand out in the flight timeline. First, SpaceX intends to test the payload bay door at T+11 minutes and 56 seconds, which is then set to close at T+28 minutes and 21 seconds. While the payload bay door is being tested, SpaceX intends to do the Tipping Point cryogenic fluid transfer test at T+24 minutes and 31 seconds.

After those events, SpaceX plans to perform an in-space Raptor relight at T+40 minutes and 46 seconds. This will likely be a simulated deorbit burn like SpaceX performed with Ship 28 on Dec 29, 2023. SpaceX filed a warning area near the original reentry location; according to Jonathan McDowell on X, this zone is consistent with a 100m/s DeltaV burn with Raptor.

After all of these separate tests, SpaceX plans to reenter Starship over the Indian Ocean rather than north of Hawaii as with the previous two flights. This is a safer trajectory than with Hawaii, since a burn is planned it will guarantee that no matter what Ship 28 will reenter over water. 

Teams have been working a lot on Ship 28’s heatshield, which suggests that SpaceX wants to give this vehicle the best chance possible of making it through reentry.

Expectations For Flight

SpaceX has said on the info page about Flight 3 that teams would like to get data from all of the in-flight tests that are scheduled to be performed and that this flight test aims to build on what teams have learned from the previous two flight tests.

In order for this to be more of a success than Flight 2, Ship 28 needs to at least get to reentry, and Booster 10 needs to get past boost back burn.

If Ship 28 reenters successfully and splashes down in the Indian Ocean in one piece, and Booster 10 completes its landing burn, Last but not least, if no anomalies or property damage occurred, SpaceX will not be required to complete a mishap investigation as defined in Federal Aviation Regulations Part 450.173.

But if there is an anomaly then SpaceX will have to perform a mishap investigation just like the last two flights. 

Looking ahead

After Flight 3, there is Flight 4, which is currently slated to be Ship 29 and Booster 11. Now Ship 29 has already completed a spin prime before being rolled back to the production site, and Booster 11 is patiently waiting its turn to have the OLM.

Its going to be very interesting to see how quickly Flight 4’s test campaign will be and how quickly it will be ready for launch.

Feature Image: Polaris Program flyby of IFT-3. Credit: Jack (@thejackbeyer) For NSF.

The post After Months of Preparations Starship is Ready for Flight 3 appeared first on NASASpaceFlight.com.



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