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DeepSpace: Firefly’s Alpha rocket to get a massive upgrade with ion thruster boost stage ⚡ ?

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Eric Ralph · June 18th, 2019

Welcome to the latest edition of DeepSpace! Each week, Teslarati space reporter Eric Ralph hand-crafts this newsletter to give you a breakdown of what’s happening in the space industry and what you need to know. To receive this newsletter (and others) directly and join our member-only Slack group, give us a 3-month trial for just $5.


Although the company quietly teased the concept for the first time several months ago, Firefly has released a detailed update on its Orbital Transfer Vehicle (OTV), an ambitious spacecraft meant to complement its Alpha and Beta launch vehicles. If Firefly can deliver on the independent spacecraft’s technical promises, the combination of Alpha (~$15M) and OTV could help usher in a new era of small, high-performance satellites launched on small, high-performance rockets.

In fact, Rocket Lab – currently the world’s only truly commercial smallsat launch provider – has already demonstrated the power of this new paradigm, albeit on a smaller scale. After just one failed attempt, the first successful orbital launch of the company’s Electron rocket also marked the surprise debut of a tiny third stage used to circularize the payload’s orbit. After five successful uses in orbit, Rocket Lab has taken its third stage a step further, adding redundant avionics, solar arrays, and more to effectively create an independent spacecraft/satellite bus called Photon. By all appearances, Firefly’s OTV is much larger than Photon but is functionally quite similar. By taking advantage of Alpha’s significant performance benefits compared to Electron, Firefly has designed a third stage/spacecraft capable of delivering hundreds of kilograms to geostationary orbit, the Moon, and (perhaps) beyond.

Changing the delta V game

  • Generally speaking, OTV is quite small. According to Firefly’s Payload User’s Guide, the spacecraft will weigh just 130 kg (285 lb) dry and will carry perhaps 30-70 kg of xenon fuel for its electric ion thrusters. This is a critical differentiator relative to Rocket Lab’s Photon and kick stage, which rely on the inefficient (but simple and reliable) Curie chemical rocket engine.
    • According to Firefly, Alpha is designed to launch a max of 1000 kg (2200 lb) to a 200 km (125 mi) low Earth orbit (LEO). Given OTV’s ~200 kg wet mass, Alpha + OTV offer some incredible capabilities relative to the rocket’s size and design.
    • Powerful electric thrusters undeniably add a lot of complexity to any spacecraft that chooses to use them but that pain is often deemed worth it for the benefits they can offer. Most notably, ion propulsion is extremely efficient.
This graph demonstrates the potential performance benefits of Alpha + OTV relative to Alpha on its own. (Firefly)
  • Thanks to OTV’s efficient electric thrusters and light carbon composite structure, the potential benefits of Alpha + OTV are hard to believe for a rocket as (relatively) small as Alpha.
  • On its own, Alpha can only deliver a meaningful payload (~100 kg) to perhaps 4000 km (2500 mi). With OTV, Alpha can suddenly deliver ~600 kg to a circular geostationary orbit (~36,000 km, 22,300 mi) and upwards of 400-500 kg into orbit around the Moon.
    • For reference, despite weighing around 10% of Falcon 9, Alpha and OTV would offer perhaps 10-15% the performance of Falcon 9 to trans lunar injection (TLI). This utterly defies the general rule of thumb that as a rocket gets significantly smaller, its performance (particularly to higher-energy orbits) deteriorates disproportionately.
  • With OTV, Alpha – nominally a ~$15M launch vehicle relegated to LEO payloads – becomes an incredibly intriguing option for small geostationary communications satellites and small-scale public and private exploration of the Moon, near Earth asteroids, and maybe even Mars/Venus.
  • According to a senior Firefly investor and board member, Firefly hopes to have OTV ready for its orbital debut on Alpha’s third launch, tentatively scheduled no earlier than mid-2020.

Alpha readies for launch

  • Of course, OTV is a bird without wings without Firefly’s Alpha launch vehicle. Weighing 54,000 kg (120,000 lb) fully-fueled, Alpha is a two-stage rocket that will stand 1.8m (6ft) wide and 29m (95ft) tall. Powered by four Reaver engines, the first stage will produce ~740 kN (166,000 lbf), approximately 85% of one of Falcon 9’s nine Merlin 1D engines.
  • Firefly is working relentlessly towards an ambitious December 2019 Alpha launch debut, a target that will probably slip into early 2020 due to the inherent complexity of the task at hand. Critically, though, Firefly has made a huge amount of progress towards that goal.
    • Notably, Firefly’s second stage – powered by one vacuum-optimized Lightning engine – has already been qualified for launch with full-duration static fires at the company’s Texas facilities. Firefly is in the midst of preparing for an identical series of qualification tests for its more powerful first stage, shown above in the form of one Reaver engine attached to an Alpha S1 thrust structure.
    • As early as July, a full set of four Reaver engines will be installed on the same thrust structure to perform static fire testing, much like SpaceX gradually added Merlin 1D engines during Falcon 9 development testing.
  • If all goes as planned, Firefly will have completed its first Alpha rocket – first stage, second stage, and payload fairing – by October or November 2019. Expect plenty of new photos and updates as Alpha nears its inaugural launch.
Thanks for being a Teslarati Reader! Become a member today to receive an issue of DeepSpace in your inbox each week!

– Eric

 

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.

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Why Tesla Roadster unveiling delay might have nothing to do with it flying

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tesla roadster elon musk flying
Credit: Grok

Tesla announced on Monday that the Roadster event scheduled for today would be postponed due to the need for it to be held outside.

Less than 24 hours later, CEO Elon Musk broadened that by stating it was due to high winds, immediately sending everyone into a frenzy over the Roadster’s potential ability to fly.

And realistically, it could definitely have to do with it flying, hovering, or hopping; whatever Tesla has in mind for this demonstration could not be impacted by wind. However, it might have nothing to do with the vehicle flying whatsoever, and instead could be a simple precaution, as the Roadster is a very unique vehicle with some already official specs that are just mind-blowing.

Tesla will very, very likely be showcasing both the acceleration rate and potentially even a top speed demo at the event in Waco. Both of these demonstrations, performed with a vehicle that has such incredibly fast metrics, could easily be impacted by wind as well.

Tesla Roadster event requires restricted airspace, and the FAA obliges

Top Speed Demo

At high speeds, aerodynamic forces are already overwhelmingly present. A crosswind or sudden gust adds a layer of sideways force that the tires must counter with slip angle. On a short demo course, that force can shove the car off the intended line, especially in a light car with a low frontal area and little mass to resist the push.

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Electric cars, due to their battery packs, have an advantage of an extremely low center of gravity, giving them extra stability. However, the speeds at which the Roadster could travel at the demo could spell some issues if crosswinds are present.

Gusts are worse than a steady wind because the load changes faster than a driver can smoothly correct. That shows up as weaving or a late correction. Headwinds and tailwinds can also spell disaster. Headwinds cut a measured top speed but raise the power needed to get there or maintain it. Meanwhile, a tailwind can inflate the top speed, and downforce issues could become more noticeable.

Wind also loads the body unevenly. A low car can feel light on the upwind side or see a sudden change in downforce if the gust hits a wing or diffuser at an angle. Tire temperature and pressure might stay near a normal level, but lateral grip can be lost as the vehicle is spent fighting the wind.

Acceleration Demo

Launch and 0-60 MPH runs are shorter, so the car spends less time exposed to forces that could cause things to go awry. However, the first second is very sensitive, as a crosswind at launch could yaw the car before speed builds and prior to aerodynamic impact being too great. The driver will be required to correct traction control or manage how much the wheels are spinning, which will likely be corrected automatically by some sort of traction control system within the Roadster (we are fairly certain Tesla will implement something brilliant with it).

These things could cause an unstable run.

A headwind would increase drag as speed rises, while a tailwind would do the opposite. Meanwhile, surface effects, like wind-driven dust, light debris, or even rain, could reduce grip at the exact moment the tires are asked for peak longitudinal force. Standing water plus a crosswind is a common reason an acceleration attempt might be scrapped.

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Flying or Not

No matter what Tesla has in store for the Roadster, waiting for ideal conditions is a great idea. People who follow and support the company, along with the engineers involved in the Roadster program, have been waiting nine years since the last unveiling for this moment. Everything should be ideal.

Some speculate that it’s just not ready, and that’s ridiculous. Why would Tesla even schedule the event — albeit prematurely — after nine years if it was not ready? Why would they jump the gun now?

We were all excited for today, but it truly is the most ideal thing in the world to wait two more weeks so everything, including the weather, can be perfect. The delay is simply worth it. But Tesla, seriously, make this the last one.

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SpaceX nails “Lucky 13” astronaut launch, leaning into Tesla tradition and superstition

SpaceX launched Crew-13 astronauts to the ISS Thursday, setting up a record fast Dragon docking.

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Crew Dragon sits atop Falcon 9 at sunrise on Cape Canaveral's pad 40, less than a day before four astronauts are set to launch to the ISS. (Credit: SpaceX)

SpaceX launched NASA’s Crew-13 mission to the International Space Station on Thursday morning, getting four astronauts to orbit despite a forecast of thunderstorms and gusty winds that had threatened to push the flight to Friday.

Falcon 9 lifted off from Space Launch Complex 40 at Cape Canaveral Space Force Station at 11:10 a.m. ET carrying Dragon Grace, NASA confirmed. On board are NASA commander Jessica Watkins, NASA pilot Luke Delaney, Canadian Space Agency astronaut Joshua Kutryk and Roscosmos cosmonaut Sergey Teteryatnikov. The first stage booster, B1101, landed at Landing Zone 40 beside the pad on its third flight after previously supporting Crew-12 and a Starlink mission.

It was the first spaceflight for Delaney, Kutryk and Teteryatnikov. Watkins, who flew on Crew-4 in 2022, became the first NASA astronaut to launch aboard a Crew Dragon twice.

Before launch, the crew rode to the pad in Teslas, a tradition on NASA’s SpaceX crew flights since 2020. This time the cars carried specialty plates reading “Lucky 13.” Watkins said the mission patch leans into the number on purpose, as a nod to Apollo 13 and the resilience of that crew.

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Grace is now on a short trip to the station. Docking at the forward port of the Harmony module is scheduled for about 7 p.m. ET, roughly 7 hours and 50 minutes after liftoff, which Space.com notes would be the fastest Crew Dragon transit to the ISS yet. Most Dragon flights take around 15 to 24 hours to catch the station. Hatch opening is planned for 8:25 p.m. ET.

The launch came more than two weeks later than originally planned. An oxidizer leak was found in Grace’s propulsion system in August, and NASA and SpaceX added time for tests. That pushed back the return of Crew-12, which has been aboard the station since February and is now set to splash down off Southern California next week. Crew-13 is expected to stay about six months.

SpaceX rescue mission for stranded ISS astronauts nears end — Here’s when they’ll return home

SpaceX already holds NASA orders for crew rotations through Crew-17, while Boeing is preparing an uncrewed Starliner flight to the station as early as December.

Crew-13 was only the first of three SpaceX launches planned for Thursday, as Teslarati previewed on Wednesday. A Falcon 9 launched its Transporter-18 mission from California today, where Google will be launching its first orbital artificial intelligence (AI) test satellite. Meanwhile, Falcon Heavy is set to launch the classified NROL-97 mission for the National Reconnaissance Office from Launch Complex 39A at 11:53 p.m. ET. Its two side boosters will return to Landing Zones 1 and 2, which means Central Florida could hear up to three sonic booms in a single day. The busy stretch follows Starship’s Flight 14 on Monday, which reached orbit for the first time.

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Tesla moves forward on Wireless Charging for vehicles

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Credit: Tesla | X

Tesla has moved its Wireless Charging efforts for its electric vehicles forward, as it had a new patent published today, one that it submitted back in March.

The patent describes a system for detecting foreign objects on the wireless charging pad under varying temperatures, aiming to mitigate any undesired results that could come from something being on top of the charging pad.

The abstract of the patent states:

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“The present disclosure relates to methods and systems that can reliably detect foreign objects on a wireless charging pad under varying temperatures. In some examples, an object detector can utilize a set of inductive coils included in resonant tanks, and excite the resonant tanks using signals in a range of frequencies including or near a nominal resonant frequency of the resonant tanks. The object detector can detect a metal object based on resistance of a coil increasing and inductance of the coil decreasing. By analyzing the shifts and/or distributions in resonant frequencies and output magnitudes (e.g., output voltage peaks), the object detector can distinguish between changes of frequencies and magnitudes caused by temperature and those caused by foreign objects to accurately detect the foreign objects.”

The object detection system will utilize a set of inductive coils included in resonant tanks, and “excite the resonant tank using signals in a range of frequencies including or near a nominal resonant frequency of the tanks.” Metal can be detected by an increase in the coil’s resistance and a decrease in the coil’s inductance.

By analyzing shifts or disruptions in resonant frequencies and output magnitudes, the system can detect foreign objects. These types of safeguards need to be implemented through the normal operation of the charging pads.

Tesla says its Cybercab wireless charging efficiency is ‘well above 90%’

Tesla plans to utilize wireless charging with Cybercab and Robotaxi-enabled units to help streamline the fully autonomous experience from A to Z. The last thing the company wants to do is have any sort of small obstruction preventing the rider from experiencing Robotaxi as intended.

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