Connect with us

News

SpaceX sends “radically redesigned” Starship engine to Texas for hot-fire tests

As of September 2017, subscale Raptor engines had been cumulatively fired for more than 1200 seconds in just 12 months of testing. (SpaceX)

Published

on

SpaceX has shipped one of the first of a group of Starship engines known as Raptor, described last month by CEO Elon Musk as “radically redesigned”. A culmination of more than 24 months of prototype testing, the first flight-worthy Raptor could be ignited for the first time as early as February.

According to Musk, three of these redesigned Raptors will power the first full-scale BFR prototype, a Starship (upper stage) test article meant to conduct relatively low-altitude, low-velocity hop tests over the southern tip of Texas. Those tests could also begin next month, although a debut sometime in March or April is increasingly likely.

Effectively designed on a blank slate, Raptor began full-scale component-level tests in 2014 at NASA’s Mississippi-based Stennis Space Center, evolving from main injector development to oxygen preburner hot-fires in 2015. Soon after Raptor’s prototype preburner design was validated at Stennis, SpaceX moved testing to its privately-owned and operated facilities in McGregor, Texas, where Raptor static fire testing has remained since.

Just days before CEO Elon Musk was scheduled to reveal SpaceX’s next-generation rocket (BFR, formerly known as the Interplanetary Transport System or ITS) in September 2016, he announced in a tweet that propulsion engineers and technicians had successful hot-fired an integrated Raptor prototype – albeit subscale – for the first time ever. Just 12 months later, Musk once again took to the stage to announce an update to BFR’s design, while also revealing that prototype Raptor engines had already completed more than 1200 seconds (20 minutes) of cumulative hot-fire tests, an extremely aggressive and encouraging rate of progress for such a new engine.

Although Raptor undoubtedly borrows heavily from much of the same expertise that designed Merlin 1 and operated and improved it for years, that is roughly where the similarities between Raptor and M1D end. M1D, powered by refined kerosene (RP-1) and liquid oxygen, uses a combustion cycle (gas-generator) that is relatively simple and reliable at the cost of engine efficiency, although SpaceX propulsion expertise still managed to give M1D the highest thrust-to-weight ratio of any liquid rocket engine ever flown. Still, measured by ISP (instantaneous specific impulse), M1D’s inefficient kerolox gas-generator cycle ultimately means that the engine simply can’t compete with the performance of engines with more efficient propellants and combustion cycles.

While SpaceX’s Falcon 9 and Heavy rockets – powered by Merlin 1D and Merlin Vacuum – are more than adequate in and around Earth orbit, a far more efficient engine was needed for the company to enable the sort of interplanetary colonization Musk had in mind when he created SpaceX. Raptor was the answer. Ultimately settling on liquid methane and oxygen (methalox) as the propellant and a full-flow staged-combustion (FFSC) cycle, Raptor was designed to be extraordinarily reliable and efficient in order to safely power a spacecraft (BFS/Starship) meant to ferry dozens or hundreds of people to and from Mars.

Advertisement
-

An excellent NASASpaceflight article explores the engine’s journey from a blank sheet to integrated static-fire tests and offers a deeper explanation of the technical details.

Raptor enters a new era

For all the extensive and invaluable testing SpaceX has done with a series of prototype Raptor engines, the engines tested were subscale versions with around 30% the thrust of the c. 2016 Raptor and around 40-50% of the updated c. 2017 iteration, producing almost the same amount of thrust as Merlin 1D (914 kN to Raptor’s ~1000 kN). In September 2018, Musk described Raptor as an “approximately…200-ton (~2000 kN) thrust engine” that would eventually operate with a chamber pressure as high as 300 bar (an extraordinary ~4400 psi), requiring at least one of the FFSC engine’s two preburners (used to power separate turbopumps) to operate at a truly terrifying ~810 bar (nearly 12,000 psi).

Conveniently stood beside a Merlin 1D engine also ready for hot-fire acceptance testing, the Raptor engine spotted departing SpaceX’s Hawthorne, CA factory last week was reportedly immense in person, towering over an M1D engine. Raptor also featured a mass of spaghetti-like plumbing (complexity necessary for its advanced combustion cycle), with a significant fraction of the metallic pipes and tubes displaying mirror-like finishes. Most notable was an obvious secondary preburner/turbopump stack and the lack of any exhaust port, whereas M1D relies on a single turbopump and exhausts the gases used to power it. Raptor’s full-flow staged-combustion cycle uses separate oxygen and methane preburners to power separate turbopumps, significantly improving mass flow rate and smoothing out combustion mixing.

 

Unlike all previous hot-fired Raptors, those shipping now to McGregor, Texas are expected to be the first completed engines with a finalized design, arrived at only after a period of extensive testing and iterative improvement. They also appear to be full-scale, meaning that the test bays dedicated to Raptor will likely need to be upgraded (if they haven’t been already) to support a two- or threefold increase in maximum thrust.

SpaceX’s Starship hopper will need three finalized engines, meaning that the Raptor now in McGregor, Texas may not have been the first to arrive. Nevertheless, the shipment of full-scale hardware is always an extremely encouraging milestone for any advanced technology development program, while also foreshadowing the first imminent static-fires of the “radcally redesigned” rocket engine. With hardware now at the test site before January is out, a February test debut – one month behind a January debut teased by Elon Musk last December – is not out of the question.


Check out Teslarati’s newsletters for prompt updates, on-the-ground perspectives, and unique glimpses of SpaceX’s rocket launch and recovery processes!

Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

Advertisement
Comments

News

FCC green lights SpaceX’s move to a showdown with Verizon and AT&T

The FCC advanced plans opening 482 MHz to satellite phone service, boosting SpaceX’s Starlink Mobile.

Published

on

By

A hand holds a smartphone displaying the Starlink Mobile app interface showing a strong “Connected – Direct to Cell” signal, with a Starlink satellite beaming connectivity signals down to Earth from orbit. The background features the planet’s night side glowing with city lights against the curve of the atmosphere, set above a scenic twilight landscape.

The Federal Communications Commission voted Thursday to move forward with a proposal that would open an additional 482 MHz of spectrum to satellite service beamed directly to ordinary phones, a step that could widen the road for SpaceX’s Starlink Mobile to compete with the country’s largest wireless carriers.

The commission adopted the notice of proposed rulemaking at its October open meeting in Washington, Reuters reported. The proposal would raise the number of bands eligible for Supplemental Coverage from Space from five to 13, according to the FCC fact sheet. Commissioners also advanced a companion item proposing an auction of 25 MHz in the 1675 to 1695 MHz and 2020 to 2025 MHz bands, which could be used for terrestrial service, direct to device service or both.

Thursday’s vote does not hand any spectrum to SpaceX. It opens a public comment period, and final rules will come later. Under the draft, comments would be due 60 days after the notice is published in the Federal Register. The FCC had not released the adopted text at the time of writing, so it is not yet clear whether any bands were changed before the vote.

That question is where the fight now moves. AT&T, Verizon and T-Mobile, through industry group CTIA, asked the FCC to drop the 2.5 GHz and 3.45 GHz bands, which make up 290 MHz of the 482 MHz on the table, as Teslarati reported ahead of the vote. T-Mobile argued satellite interference could wipe out up to 96% of a cell site’s uplink coverage area. SpaceX asked the commission to go the other way and add the 902 to 928 MHz band.

The rule change that matters most to SpaceX may be a structural one. Today, a satellite operator must lease spectrum from every carrier holding co-channel licenses across an entire region such as the contiguous United States. The proposal would replace that with a certification that the operator has coexistence agreements covering only the areas it plans to serve, or that it holds the terrestrial licenses itself.

Advertisement
-

SpaceX has spent this year building that second path. It bought EchoStar’s AWS-4 and H-block licenses in a deal worth roughly $17 billion, and earlier this month agreed to acquire Grain Management’s nationwide 800 MHz portfolio, which the company said would pave the way for Starlink to become a major US mobile carrier. The FCC approved SpaceX’s purchase of three unused AWS-3 licenses from Tristar on October 21, and cleared its plan for 15,000 next generation direct to cell satellites on October 6.

The regulator has not always sided with SpaceX. In April, the FCC dismissed a SpaceX petition seeking access to Mobile Satellite Service spectrum held by incumbents, and it rejected 2.5 GHz for satellite coverage when it first adopted the framework in 2024.

The carriers are also building their own defenses. In May, the three companies agreed in principle to form a joint venture pooling spectrum for satellite service, and T-Mobile remains SpaceX’s US launch partner for Starlink Mobile even as it leads the push to keep satellites out of 2.5 GHz. SpaceX President Gwynne Shotwell has said service on SpaceX’s own airwaves is targeted for early 2028.

Continue Reading

Elon Musk

Tesla’s Roadster appearance at SpaceX has merger watchers talking

Tesla’s next generation Roadster was spotted at SpaceX’s Hawthorne headquarters, two weeks after its unveiling.

Published

on

By

The Roadster’s rear wing, one of the aerodynamic elements Tesla pairs with a fan-based downforce system. (Image: Tesla)

Tesla’s next generation Roadster turned up at SpaceX’s headquarters in Hawthorne, California on Wednesday, less than two weeks after the car flew off a ramp at its unveiling in Texas.

Photos shared on X by SpaceX Engineer (@DeannaRiceSPCX) show the new Roadster parked outdoors beside the famed Falcon 9 that stands outside company headquarters at the corner of Crenshaw Boulevard and Jack Northrop Avenue. Rocket B1019 was the first orbital-class booster ever to land after a launch on December 21, 2015 after it sent 11 Orbcomm satellites to orbit and then flew back to Landing Zone 1 at Cape Canaveral, which would be the first landing in what became SpaceX’s reusable rocket program. SpaceX chose not to fly it again. After a test fire in Florida, the booster was shipped to Hawthorne and raised upright as a permanent monument in August 2016, as Teslarati reported at the time. Putting the Roadster, which flies on SpaceX cold gas thrusters, next to the rocket that started SpaceX’s landings is symbolic in itself.

The Thrust and Rocket versions of the Roadster use cold gas thrusters fed by composite overwrapped pressure vessels, the same type of tank SpaceX flies on Falcon 9, and Elon Musk described the car as the work of Tesla and SpaceX engineers working together. Tesla lists 0 to 60 mph in under 0.9 seconds for Thrust and under 0.59 seconds for Rocket, while the base Performance model relies on a fan and ground sealing system for grip, as Teslarati detailed in its breakdown of the three Roadster configurations.

Tesla has kept the car in the spotlight since the October 15 event near Waco. Last week, the company posted a video of the Roadster’s fighter jet inspired cockpit, including a Track Mode screen with a “Thruster · 5,500 PSI” readout, which we covered in our look at the Roadster’s center display. Musk also said owners will be able to ask the car to perform the stunts autonomously, and promised a looping track at Tesla’s Texas headquarters.

The visit comes as special committees at Tesla and SpaceX weigh a possible merger, a step Musk confirmed on SpaceX’s third quarter earnings call. The Roadster, built on SpaceX hardware, has become one of the clearest examples of the two companies already building products together.

Musk said at the unveiling that Roadster production will begin in 2028. Reservations are open with a $50,000 payment, Thrust is listed as a limited release and Rocket is invite only. Tesla says the car is not approved for public road use.

Continue Reading

News

Verizon, AT&T and T-Mobile are trying to shut Starlink out before FCC vote

AT&T, Verizon and T-Mobile want 290 MHz cut from an FCC satellite plan before Thursday.

Published

on

By

Starlink D2D direct to device vs Verizon, AT&T (Concept render by Grok)

AT&T, Verizon and T-Mobile are asking the Federal Communications Commission to pull nearly 300 MHz of spectrum out of a proposal that would let satellite companies like SpaceX offer cell service directly to ordinary phones. The request lands one day before the agency votes on it.

The FCC will vote Thursday, October 29, on a notice of proposed rulemaking that would make an additional 482 MHz available for direct to device service, expanding the number of eligible bands from five to 13, according to the FCC fact sheet. It would also scrap the rule requiring a satellite operator to lease spectrum from carriers, replacing it with a certification that the operator has coexistence agreements in place or holds the terrestrial license itself.

That second path matters for SpaceX. As Teslarati reported earlier this month, SpaceX agreed to buy Grain Management’s nationwide 800 MHz portfolio to turn Starlink Mobile into a full US carrier, adding to the spectrum it already bought from EchoStar.

The carriers want two bands removed, 2.5 GHz and 3.45 GHz, which make up 290 MHz of the 482 MHz on the table. Through industry group CTIA, they argued that about 300 million users depend on those bands and that satellite operations in them are not technically feasible. T-Mobile, which calls 2.5 GHz the foundation of its Ultra Capacity 5G network, said in its own filing that satellite interference could wipe out up to 96% of a cell site’s uplink coverage area and cut uplink speeds by 88% to 99%.

Executives from all three carriers met with FCC staff on October 20, and T-Mobile CEO Srini Gopalan met separately with FCC Chairman Brendan Carr. T-Mobile’s role stands out because it is still SpaceX’s US launch partner for Starlink Mobile. The three carriers have also teamed up on their own satellite joint venture to pool spectrum, a move widely seen as a response to Starlink.

Advertisement
-

SpaceX is asking for the opposite. In an October 23 filing after meetings with FCC staff and commissioners’ offices, the company asked regulators to add the 902 to 928 MHz band to the proposal. “Doing so now saves time later,” SpaceX wrote. The company also asked the FCC to modernize interference rules and align satellite deployment requirements with those for terrestrial cell networks, saying the goal is to let satellite and ground networks work together so Americans stay connected wherever they are.

The carriers have not been shy about how they view SpaceX as a competitor. On Verizon’s third quarter earnings call Monday, its chief executive said Starlink Mobile “just can’t compete with a terrestrial network” and estimated SpaceX would need four to six years and $300 billion to $500 billion to build a full US carrier network.

Thursday’s vote will not settle which bands survive. Adopting the notice opens a public comment period, with final rules to come later in the proceeding. The FCC already considered and rejected 2.5 GHz for satellite coverage once, in 2024. SpaceX also is not the only satellite player watching: the FCC approved Amazon’s $11.6 billion acquisition of Globalstar on October 27, giving its planned direct to device fleet its own mobile satellite spectrum.

Continue Reading