30.12.2021
FAA delays completion of Starship environmental review
SANTA FE, N.M. — The Federal Aviation Administration says it needs at least two more months to complete an environmental review of SpaceX Starship orbital launches from its Boca Chica, Texas, facility.
The FAA said Dec. 28 that was unable to meet an original Dec. 31 deadline to complete an environmental assessment of plans by SpaceX to conduct orbital launches of its Starship/Super Heavy vehicle from the Boca Chica facility the company calls Starbase. That review, formally known as a Programmatic Environmental Assessment (PEA), is a key requirement for obtaining an FAA launch license needed for those launches.
“However, due to the high volume of comments submitted on the Draft PEA, discussions and consultation efforts with consulting parties, the FAA is announcing an update to the schedule,” the FAA stated on its website. “The FAA now plans to release the Final PEA on February 28, 2022.”
The FAA received more than 18,000 public comments to the draft version of the report, released in September. SpaceX is working to respond to those public comments under the supervision of the FAA, the agency noted, but did not give further details about the analysis of the comments. Two public hearings about the review in October generated many comments both supportive and critical of SpaceX’s plans.
The environmental review process also includes consultations with other government agencies. The FAA noted that those consultations involve those regarding endangered species and preservation of historical sites.
The postponed completion of the environmental review means a delay in the award of an FAA launch license for Starship/Super Heavy orbital launches from Boca Chica. In November, SpaceX Chief Executive Elon Musk said he expected to get the launch license at the end of 2021 with a first orbital launch projected for January or February 2022.
It is not clear, however, that SpaceX would be ready for an orbital launch attempt on that schedule even if the environmental review and licensing process was completed as previously planned. Musk said in November that SpaceX would perform a “bunch of tests” of the Starship vehicle and its Super Heavy booster in December, but many of those anticipated tests, such as static fires, have not occurred yet.
There is also no guarantee that the new Feb. 28 deadline will not be extended again. An environmental review of a proposed launch site in Georgia, Spaceport Camden, suffered a series of delays lasting months before the FAA awarded a spaceport license for the facility Dec. 20.
Quelle: SN
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Update: 31.12.2021
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SpaceX fires up Starship SN20 prototype again ahead of landmark test flight
SN20 continues to prep for a landmark orbital test flight.
SpaceX's Starship SN20 prototype performs a six-engine static fire test in South Texas on Nov. 12, 2021. SN20 performed another static fire on Dec. 29, 2021. (Image credit: Spadre.com)
SpaceX's latest Starship prototype has breathed fire again.
The Starship SN20 vehicle performed a "static fire" test on Wednesday (Dec. 29) at the company's Starbase site in South Texas, briefly igniting its Raptor engines while remaining anchored to the ground.
The trial continued the launch-prep campaign for SN20 ("Serial No. 20"), which is scheduled to conduct the Starship program's first-ever orbital test flight in the coming months. That landmark liftoff had been targeted for January or February, but it'll now take place no sooner than early March because the U.S. Federal Aviation Administration just pushed the estimated completion date of a required Starbase environmental review from Dec. 31 to Feb. 28.
SN20 has performed static fires before. The vehicle lit up all six of its Raptors on Nov. 12, for example. Wednesday's test, which NASASpaceflight streamed live, may have involved all six engines as well, though SpaceX has yet to confirm that.
SpaceX is developing Starship to take people and cargo to the moon, Mars and beyond. The vehicle consists of two elements, both of which are designed to be fully and rapidly reusable: a huge first-stage booster called Super Heavy and a big spacecraft known as Starship.
Starship prototypes have flown before, but only on short jaunts that reached maximum altitudes of around 6.2 miles (10 kilometers). Those previous launches involved Starship vehicles with no more than three Raptors, and none of them lifted off atop a Super Heavy booster.
The upcoming orbital flight will see SN20 fly atop a Super Heavy called Booster 4, which sports 29 Raptors of its own. If all goes according to plan, Booster 4 will splash down in the Gulf of Mexico shortly after liftoff and SN20 will make it all the way to orbit, eventually performing a splashdown of its own near the Hawaiian island of Kauai.
More test flights will likely follow in quick succession, for SpaceX aims to get Starship up and running relatively soon. NASA chose Starship as the first crewed lander for its Artemis program, which aims to put people on the moon in the middle of the decade.
And Japanese billionaire Yusaku Maezawa, who recently returned from a 12-day stay aboard the International Space Station, booked a round-the-moon trip on Starship, with launch targeted for 2023.
Quelle: SC
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1st orbital test flight of SpaceX's Starship Mars rocket pushed to March at the earliest
A required FAA environmental assessment now won't be done until Feb. 28.
This SpaceX photo shows the first test-fire of six Raptor engines on the company's Starship SN20 rocket prototype on Nov. 12, 2021 at the Starbase facility in near Boca Chica Village in South Texas. A Starship Super Heavy booster stands at right. (Image credit: SpaceX)
We'll have to wait a bit longer for the orbital debut of SpaceX's Starship Mars rocket.
SpaceX had been aiming to launch Starship on its first orbital test flight in January or February, provided that the U.S. Federal Aviation Administration (FAA) wrapped up a programmatic environmental assessment (PEA) of the company's South Texas launch site by Dec. 31 as planned.
But that timeline no longer applies. The FAA announced on Tuesday (Dec. 28) that it has pushed the release of the final PEA back to Feb. 28, citing "the high volume of comments submitted on the draft PEA" and "discussions and consultation efforts with consulting parties."
Members of the public submitted more than 18,000 comments about the draft PEA, which was released on Sept. 17, FAA officials wrote in an update Tuesday.
SpaceX is developing Starship to get people and cargo to the moon, Mars and other deep-space destinations. NASA has already signed up for a ride, choosing Starship as the first crewed moon lander for the agency's Artemis lunar exploration program.
The huge vehicle consists of two fully reusable elements: a first-stage booster called Super Heavy and a 165-foot-tall (50 meters) spacecraft known as Starship. Both will be powered by SpaceX's next-generation Raptor engine — six for Starship and about 30 for Super Heavy.
Starship prototypes have flown before, on roughly 6.2-mile-high (10 kilometers) hops into the skies above Starbase, SpaceX's facility near the South Texas village of Boca Chica. But the upcoming orbital test flight will be a much more ambitious endeavor, launching a Starship atop a Super Heavy for the first time ever.
If all goes according to plan, the Super Heavy will splash down in the Gulf of Mexico shortly after liftoff, while the Starship vehicle will complete one loop around Earth and splash down in the Pacific Ocean, off the Hawaiian island of Kauai.
We could see that launch as soon as early March, because SpaceX plans to be ready when it gets the green light. "FAA approval is the schedule driver," SpaceX founder and CEO Elon Musk said via Twitter Wednesday (Dec. 29) in response to a question about the test flight's target date.
Quelle: SC
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Update: 4.01.2022
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SpaceX Starship prototype completes fourth static fire
In its true last act of the year, SpaceX successfully fired up its first orbital-class Starship for the fourth time in approximately two months, placing the prototype one step closer to flight readiness.
Starship S20 first left its roost in SpaceX’s Starbase factory in early August, briefly performing a fit test atop Super Heavy Booster 4 (B4) – both only partially complete at the time. Both returned to their nests for finishing touches soon after. However, relative to almost all other prototypes SpaceX has built in South Texas in the last two years, Starship S20’s path to flight readiness has been a long and windy one. It took SpaceX a full eight weeks after that first rollout to prepare Ship 20 for – and complete – its first cryogenic proof test, in which the rocket was pressurized and filled with hundreds of tons of liquid nitrogen (LN2).
It took another three weeks after that milestone for SpaceX to then prepare Ship 20 for an even more important test – its first Raptor engine static fire.
The process began on October 19th with Ship 20’s first Raptor preburner test, in which smaller secondary combustion chambers designed to supply the engine’s main combustion chamber with a combustible mixture were briefly ignited on their own. On October 21st, that next milestone finally came, with Starship S20 not only completing the first on-pad static fire of a Raptor Vacuum engine but also performing a second test during the same window, firing up the same RVac and a gimballing Raptor Center (RC) engine less than an hour later. It was an impressive leap in apparent confidence, with Ship 20 jumping from the slowest prototype to reach a testing milestone to the first prototype of any kind to complete back-to-back static fires less than an hour apart.
After another unusually long three weeks of work, some of which was spent installing four more Raptors on Starship S20, the ship completed a second preburner test – the first of any kind to simultaneously feature or involve six Raptor engines. Unlike the first campaign, which had a two-day gap, SpaceX then turned S20 around in the same window and performed the first six-Raptor Starship static fire 50 minutes later – both a success, according to CEO Elon Musk.
Another Ship 20 static fire was subsequently attempted another three or so weeks later, ultimately resulting in an abort on December 1st. Only four weeks later did SpaceX try again, successfully completing what appeared to be Starship S20’s second six-engine static fire without issue on December 29th. The company attempted a second static fire a few hours later but that try was less lucky, culminating in an abort seconds before ignition and wrapping up the day’s testing. That brings us to today, January 2nd, 2022, where SpaceX is once again preparing for more Ship 20 testing with eight-hour windows on January 4th, 5th, and 6th.
The goals of these continued static fire tests are less clear than some past SpaceX testing but Ship 20 – the first orbital-class prototype and first Starship to test more than three Raptors at a time – is a valuable pathfinder. While SpaceX would likely have benefitted even more from them weeks or months, all lessons learned from Ship 20 will help guide retroactive modifications and proactive design changes for upcoming prototypes – the statuses of which are currently in flux.
SpaceX Starship ‘launch tower’ spreads its rocket-catching arms
Update: Shortly after publishing, SpaceX began a much more ambitious series of tests with the Starship launch tower’s two main arms, which are designed to lift and (one day) catch Starships and Super Heavy boosters.
After lifting the arm carriage about 15m (~50 ft), several times higher than January 3rd’s far more conservative kickoff, SpaceX fired up each arm’s main hydraulic actuator and opened them about as wide as they’re able to move. Unsurprisingly, the arms’ first powered lateral movement happenedvery slowly, obviously telegraphing caution but probably also hinting at the start of a calibration process needed to determine their full range of motion and associate those positions with certain sensor readings or telemetry to ensure they can be safely controlled. As of midnight CST, that testing has continued well into the night.
Regardless of the purpose, substantial powered movement is a major milestone for the tower’s main arms and all but guarantees that more extensive tests and simulations are soon to come.
SpaceX has moved Starbase’s rocket-catching “chopstick” arms for the first time since they were installed on the orbital Starship pad’s ‘launch tower’ two months ago.
After a shockingly brisk three-month period of assembly, the first arm installed in late August 2021 was a lone structure designed to swing in; grab and stabilize Super Heavy with its claw; fuel and power Starship; and quickly detach and swing away from the rocket during launch. A month and a half later, SpaceX begin installing a much larger pair of more complex arms in mid-October. Unlike the Starship quick-disconnect (QD) arm, the pair of arms that followed were almost nothing like anything built as part of another rocket launch complex.
Unlike other ‘arms’ related to other rocket launch facilities, the pair SpaceX began to install on Starbase’s launch tower were colossal, measuring more than 30m (100+ ft) long and 5-10m (15-30 ft) tall. Built out of heavy-duty steel pipe and affixed to an even sturdier pair of claw-like supports that grab onto the launch tower, the combined assembly likely weighs hundreds of tons. Aside from their sheer scale, Starbase’s main tower arms are also attached to a complex system of cables and an industrial-strength ‘drawworks’ commonly used on giant oil rigs and derricks.
They also feature huge actuators that allow the two arms to open and close, revealing a bit of their purpose. While the main reason they likely exist is to provide SpaceX with an all-weather alternative to cranes for lifting, manipulating, and precisely stacking Starships and Super Heavy boosters at the launch pad, the headline – ever since Musk revealed the idea – has always been plans to use those same arms to literally catch rockets out of mid-air.
To do so, they’ll need to be able to actuate and move extremely quickly and precisely up and down the Starship launch tower, matching the velocity and autonomously determining the position of landing Super Heavy boosters (and possibly Starships) to avoid major damage or the loss of entire vehicles. While arguably an unnecessary gamble and an attempt to micro-optimize the concept of operations of a rocket that’s yet to attempt a single orbital-class launch, SpaceX’s CEO is clearly committed to the idea and – whether or not the first iteration works – has fully delivered on the first complete lift-and-catch system.
On January 3rd, 2022, after removing a large amount of scaffolding in the days prior, SpaceX briefly and slightly moved the installed arms for the first time, using the drawworks to lift the entire arm-and-carriage assembly a few meters (~6 ft) up and down the tower. Once a few minor additional steps are taken, the chopsticks could be ready for much more extensive testing, beginning with basic lift, descent, and arm actuation tests to calibrate and then proof the first-of-its-kind mechanism. Later, SpaceX will likely simulate catching rockets in a wide range of scenarios. Somewhere before, during, or after that testing, SpaceX may perform another fit test with Starship S20 and Super Heavy B4 – but this time using the arms to lift and install the stages.
Quelle: TESLARATI
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Update: 13.01.2022
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SpaceX working on several Starship, Super Heavy upgrades and design changes
Not long after Elon Musk confirmed plans to add three more Raptor engines to Starship and stretch the upper stage’s propellant tanks, the SpaceX CEO has confirmed one of several smaller design changes planned in the interim.
On January 3rd, Musk confirmed that SpaceX is entirely relocating one of two secondary ‘header’ tanks that Starships use to store landing propellant. A graphic sketched on the side of future Starship rings further revealed plans to tweak most of the subsections that SpaceX stacks to form a Starship, complementing an upgraded nosecone design. Finally, another design change was spotted on hardware that will eventually become part of the first full-thrust Super Heavy booster.
According to Musk, starting with Starship 24 (S24), which is likely the next ship SpaceX will complete, the methane (fuel) header tank will be relocated from Starship’s common dome to its nosecone. From the start, Starship’s oxygen header tank has been located in the very tip of the nose – placed in such an inconvenient location for the sole purpose of shifting Starship’s center of gravity forward. Now, the methane header tank will join it in the nose, with the obvious explanation being a need to shift that center of gravity even further forward. It’s possible that this change was planned before SpaceX realized the performance benefits of a stretched, nine-engine Starship, but it could also be a preemptive modification meant to counteract the added weight of three more Raptor engines and longer tanks.
Musk’s confirmation of the methane header tank’s relocation came just a few days after a drawing on the side of a Starship section further confirmed several more minor design changes. Starbase ‘hieroglyphics’ are not uncommon, as SpaceX engineers and technicians have often used hardware itself as a sort of whiteboard to sketch out plans and literally annotate ongoing work. This particular drawing was exceptionally detailed and useful, effectively showing exactly how Starship’s design will change beginning with Ship 24. The changes are simple enough: in essence, SpaceX will be adding an extra ring to several Starship ‘sections.’ For current ships, six distinct sections are stacked to form the Starship’s cylindrical tankage and hull.
It takes another five stacked sections to complete the current nosecone design. Counting the nose as one, it takes about seven stack operations to fully assemble the basic structure of a Starship. With the design changes sketched out on a Starship S24 ring and an upgraded nosecone that will debut on the same ship, fully assembling a nosecone will now take two or three stacks (down from five) and fully assembling a Starship will take six stacks (down from seven). While obviously not a major redesign, the changes will significantly simplify (and thus potentially speed up) Starship assembly, which will have additional positive follow-on impacts on plumbing, wiring, and heat shield installation.
There’s good reason to believe that some of the changes – especially expanding Starship’s nose barrel from four to five rings tall – will end up being applied to Super Heavy, potentially reducing the number of booster ‘sections’ needed from nine to seven or eight. However, there are already signs of some weirder changes being made to Super Heavy’s design. On December 21st, a Super Heavy thrust dome – likely Booster 7’s – was sleeved with several steel rings as part of a now-routine process, partially completing the first 33-engine thrust section. However, instead of the usual aft barrel section comprised of three six-foot-tall (~1.82m) steel rings, this ‘sleeve’ was made up of four ~1.4m-tall rings – the first time in Starbase history that shorter rings have appeared on any hardware.
Unlike all the other changes described above, it’s entirely unclear what benefit SpaceX is getting from keeping a given ship or booster section the same height while adding more smaller rings to it – a process that will inherently increase the complexity and amount of work required to complete that section. Regardless, it’s clear that SpaceX is in the midst of a significant period of design revision that could see Ship 24 and Booster 7 debut with a wide range of upgrades and design changes in just a few months.
Quelle: TESLARATI
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Update: 17.01.2022
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Chopsticks tested ahead of first Mechazilla stacking operation
Having conducted the first series of Mechazilla catch and stack systems tests, SpaceX’s Starship program has come one step closer to seeing another fully stacked Starship on the Orbital Launch Mount (OLM).
Several tests were conducted with the chopsticks, paving the way for the first lift of a booster and a ship’s potential stacking following the previous full-stack operation conducted by a crane.
Chopsticks Tested:
Testing the chopsticks began the night of January 2, when they were raised a few feet before being lowered onto their resting blocks.
This was the first time the chopsticks were moved vertically, with the only prior movement being when the chopsticks were rotated to not interfere with the OLM.
Testing continued on January 4, when they were raised higher than previous tests. Each arm was rotated open individually over several hours, separately testing each significant system component for the first time.
The next test conducted was what appeared to be an exercise of the entire Mechazilla system, using the chopsticks in a simulated lift a Starship to a full-stack height before swinging the Ship Quick Disconnect (QD) arm into place to stabilize the full stack. However, this time the arms did not open wide to the position that they would be in during a launch attempt.
The next series of tests included SpaceX hooking a bar between the chopsticks before attaching multiple load test bags to the bar.
The Chopsticks were then raised, with the bags empty, to the top of the tower at a previously unseen speed, reaching the top in just under nine minutes. SpaceX later filled four of the bags with water before raising the chopsticks and translating them above the OLM.
It is hoped that checkouts of the chopsticks will allow Booster 4, or Booster 7, to be lifted onto the OLM in the coming weeks.
Following the fit check stacking of Booster 4 and Ship 20, the test campaign for Booster 4 kicked off back on December 17, with SpaceX conducting a partial cryogenic proof test, partially filling B4’s methane tank with liquid nitrogen (LN2).
These tests are conducted to verify the tanks’ structural integrity and ability to hold the super-chilled liquid methane and liquid oxygen needed for a test flight.
The next test, conducted on December 21, included SpaceX partially filling the liquid oxygen tank with LN2 for the first time, with a repeat performance for the methane tank.
The most recent test of Booster 4 saw teams fill the liquid oxygen tank with LN2 before filling the methane tank nearly halfway, potentially paving the way for the first round of static fire tests on the OLM.
However, it has not yet been confirmed that Booster 4, and the OLS Tank Farm, are at the required state of readiness for such a test.
SpaceX has not received certification to store methane in their custom-built GSE tanks, as confirmed by regulations from the Texas Railroad Commission, which regulates natural gas storage in Texas.
Should SpaceX opt to move to the next Super Heavy for Static Fire testing, Booster 7 would be the vehicle.
Stacking ops have continued in the High Bay, with the Liquid Oxygen (LOX) Aft Tank #5 being rolled into the High Bay ahead of being joined to the rest of the aft tank stack.
Once Aft Tank #5 is joined to the stack, work will shift from the LOX section to the methane section. After the methane section is completed, the Booster Thrust Section will be joined to the LOX section before the methane section is lifted and joined to the LOX section, completing the Booster.
Despite Elon only recently confirming that the next Booster would have 33 Raptor 2 (R2) engines, the first thrust puck capable of accommodating 33 R2’s was first spotted in October of 2021. This next Booster has since evolved into Booster 7, with Booster 6 becoming a test tank.
With Ship 20 having conducted a series of Static Fire tests, with the potential for more over the coming weeks, Ship 21’s tank section has been moved around the Production Site, taking up stints inside both the Mid Bay and High Bay.
Ship 21’s tank section was rolled around the Production Site, making multiple trips in and out of the Mid and High Bays before being rolled back into the Mid Bay one last time.
While work on Ship 21 has seemingly halted, SpaceX has continued to work on Ship 22, adding hinges to the nosecone barrel, indicating that the barrel could be repurposed to be a cargo bay door pathfinder.
The last time a cargo bay pathfinder was spotted was in July 2021, when a nosecone barrel was cut open along with part of the nosecone itself. At the time, Elon noted that the exact payload bay door dimensions were yet to be determined and that the volume was roughly 1,000 cubic meters.
Meanwhile, crews have started working on Ship 24, with multiple parts spotted and the Common Dome sleeved. Mary (@bocachicagal) spotted the sleeve on December 24 and captured it being put onto the sleeving stand and sleeved on January 3 and 4, respectively.
Mary also spotted the Mid LOX section on December 10 and the Forward Dome just a few days later on December 12. It would be nearly a month before more work was done on the Forward Dome, when Nic (@NicAnsuini) captured it being sleeved on January 6.
Additionally, SpaceX has continued to add capacity at the Production site, with work on the third level of the new wider High Bay starting.
Along with the previous level, SpaceX has shifted to constructing sections of the Wide Bay on the ground before lifting them onto the previous level. It appears that this change is to speed up construction, as SpaceX has been able to make progress on the second and third levels much faster than the first level.
The “Wide Bay” will allow SpaceX to work on multiple Boosters or Ships at once, something they’ve been unable to do before. Previously, Ships could only be assembled to their forward dome section in the Mid Bay before being rolled to the High Bay for nosecone integration.
The “Wide Bay” will allow SpaceX to fully assemble a Booster and Ship simultaneously before rolling them to the launch site for tests.
Quelle: NS
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Update: 29.01.2022
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SpaceX reveals Starship “marine recovery” plans in new job postings
In a series of new job postings, SpaceX has hinted at an unexpected desire to develop “marine recovery systems for the Starship program.”
Since SpaceX first began bending metal for its steel Starship development program in late 2018, CEO Elon Musk, executives, and the company itself have long maintained that both Super Heavy boosters and Starship upper stages would perform what are known as return-to-launch-site (RTLS) landings. It’s no longer clear if those long-stated plans are set in stone.
Oddly, despite repeatedly revealing plans to develop “marine recovery” assets for Starship, SpaceX’s recent “marine engineer” and “naval architect” job postings never specifically mentioned the company’s well-established plans to convert retired oil rigs into vast floating Starship launch sites. Weighing several thousand tons and absolutely dwarfing the football-field-sized drone ships SpaceX recovers Falcon boosters with, it goes without saying that towing an entire oil rig hundreds of miles to and from port is not an efficient or economical solution for rocket recovery. It would also make very little sense for SpaceX to hire a dedicated naval architect without once mentioning that they’d be working on something as all-encompassing as the world’s largest floating launch pad.
That leaves three obvious explanations for the mentions. First, it might be possible that SpaceX is merely preparing for the potential recovery of debris or intact, floating ships or boosters after intentionally expending them on early orbital Starship test flights. Second, SpaceX might have plans to strip an oil rig or two – without fully converting them into launch pads – and then use those rigs as landing platforms designed to remain at sea indefinitely. Those platforms might then transfer landed ships or boosters to smaller support ships tasked with returning them to dry land. Third and arguably most likely, SpaceX might be exploring the possible benefits of landing Super Heavy boosters at sea.
Through its Falcon rockets, SpaceX has slowly but surely refined and perfected the recovery and reuse of orbital-class rocket boosters – 24 (out of 103) of which occurred back on land. Rather than coasting 500-1000 kilometers (300-600+ mi) downrange after stage separation and landing on a drone ship at sea, those 24 boosters flipped around, canceled out their substantial velocities, and boosted themselves a few hundred kilometers back to the Florida or California coast, where they finally touched down on basic concrete pads.
Unsurprisingly, canceling out around 1.5 kilometers per second of downrange velocity (equivalent to Mach ~4.5) and fully reversing that velocity back towards the launch site is an expensive maneuver, costing quite a lot of propellant. For example, the nominal 25-second reentry burn performed by almost all Falcon boosters likely costs about 20 tons (~40,000 lb) of propellant. The average ~35-second single-engine landing burn used by all Falcon boosters likely costs about 10 tons (~22,000 lb) of propellant. Normally, that’s all that’s needed for a drone ship booster landing.
For RTLS landings, Falcon boosters must also perform a large ~40-second boostback burn with three Merlin 1D engines, likely costing an extra 25-35 tons (55,000-80,000 lb) of propellant. In other words, an RTLS landing generally ends up costing at least twice as much propellant as a drone ship landing. Using the general rocketry rule of thumb that every 7 kilograms of booster mass reduces payload to orbit by 1 kilogram and assuming that each reusable Falcon booster requires about 3 tons of recovery-specific hardware (mostly legs and grid fins) a drone ship landing might reduce Falcon 9’s payload to low Earth orbit (LEO) by ~5 tons (from 22 tons to 17 tons). The extra propellant needed for an RTLS landing might reduce it by another 4-5 tons to 13 tons.
Likely less than coincidentally, a Falcon 9 with drone ship booster recovery has never launched more than ~16 tons to LEO. While SpaceX hasn’t provided NASA’s ELVPerf calculator with data for orbits lower than 400 kilometers (~250 mi), it generally agrees, indicating that Falcon 9 is capable of launching about 12t with an RTLS landing and 16t with a drone ship landing.
This is all to say that landing reusable boosters at sea will likely always be substantially more efficient. The reason that SpaceX has always held that Starship’s Super Heavy boosters will avoid maritime recovery is that landing and recovering giant rocket boosters at sea is inherently difficult, risky, time-consuming, and expensive. That makes rapid reuse (on the order of multiple times per day or week) almost impossible and inevitably adds the cost of recovery, which could actually be quite significant for a rocket that SpaceX wants to eventually cost just a few million dollars per launch. However, so long as at-sea recovery costs less than a few million dollars, there’s always a chance that certain launch profiles could be drastically simplified – and end up cheaper – by the occasional at-sea booster landing.
If the alternative is a second dedicated launch to partially refuel one Starship, it’s possible that a sea landing could give Starship the performance needed to accomplish the same mission in a single launch, lowering the total cost of launch services. If – like with Falcon 9 – a sea landing could boost Starship’s payload to LEO by a third or more, the regular sea recovery of Super Heavy boosters would also necessarily cut the number of launches SpaceX needs to fill up a Starship Moon lander by a third. Given that SpaceX and NASA have been planning for Starship tanker launches to occur ~12 days apart, recovering boosters at sea becomes even more feasible.
In theory, the Starship launch vehicle CEO Elon Musk has recently described could be capable of launching anywhere from 150 to 200+ tons to low Earth orbit with full reuse and RTLS booster recovery. With so much performance available, it may matter less than it does with Falcon 9 and Falcon Heavy if an RTLS booster landing cuts payload to orbit by a third, a half, or even more. At the end of the day, “just” 100 tons to LEO may be more than enough to satisfy any realistic near-term performance requirements.
But until Starships and Super Heavy boosters are reusable enough to routinely launch multiple times per week (let alone per day) and marginal launch costs have been slashed to single-digit millions of dollars, it’s hard to imagine SpaceX willingly leaving so much performance on the table by forgoing at-sea recovery out of principle alone.
Quelle: TESLARATI