SpaceX’s Starship prototype nails first tethered hop during Raptor test fire

SpaceX CEO Elon Musk says that the company’s first full-scale Starship prototype has completed an inaugural hop test in South Texas, igniting its lone …

SpaceX CEO Elon Musk says that the company’s first full-scale Starship prototype has completed an inaugural hop test in South Texas, igniting its lone Raptor engine and straining against a trio of tethers attached to its legs.

While relatively minor in the scope of SpaceX’s next-generation rocket program, Starhopper’s successful tethered hop now paves the way towards untethered testing in which the terminally suborbital testbed could spend several minutes aloft and reach altitudes as high as 5 km (3 mi). Aside from Starhopper itself, this perhaps marks an even more significant milestone for Raptor, completing the engine’s first successful test-fire as part of an integrated flight vehicle.

Starhopper completed tethered hop. All systems green.

— Elon Musk (@elonmusk) April 4, 2019

Starhopper’s first successful Raptor ignition comes after the better part of two weeks of concerted testing of the integrated prototype, beginning around March 18/19. That testing included 5+ wet dress rehearsals (WDRs) that involved loading the vehicle with a significant quantity of liquid methane and oxygen propellant, verifying the performance of avionics and plumbing, and ultimately attempting to ignite Raptor.

Some challenges with ice formation in the cryogenic propellant prevalves. Hopefully overcome soon.

— Elon Musk (@elonmusk) April 2, 2019

Ironically, less than 24 hours before Starhopper’s successful ignition, SpaceX CEO Elon Musk had noted that the rough prototype, its ground systems, or both were suffering from issues caused by ice formation in propellant valves. Reading between the lines, it’s likely that the issues involved valves on both Starhopper and its ground support equipment ‘sticking’ (i.e. failing to actuate) when commanded. While not usually a particularly large risk for the overall health of the vehicle and pad, uncooperative valves will almost invariably throw a wrench in the gears of attempted rocket operations, particularly when dealing with cryogenic propellants like those used by Starhopper.

As the supercool methane and oxygen inevitably begin to warm after leaving the propellant plant and entering Starhopper’s tanks, a fraction of the liquid will gradually transition into gas and expand, requiring constant venting of the tanks to prevent overpressure events that could damage or destroy the rocket. Falcon 9 and Heavy exhibit this same behavior, as do most other liquid-fueled rockets. This helps to explain the massive venting seen throughout Starhopper’s half-dozen or so WDR tests, as well as large but routine fireballs as excess methane gas was burned off as part of the process of vehicle and pad pressure regulation.

One of Starhopper’s three tethers, April 2nd. (NASASpaceflight – bocachicagal)
Workers labor beneath Starhopper in the days leading up to the vehicle’s first hop test and Raptor ignition. (NASASpaceflight – bocachicagal)

According to Musk, “all systems [were] green” during Starhopper’s most critical test yet. If Raptor and its prototype host are still in good health after their integrated three-second ignition test, SpaceX could attempt several more static fires and tethered hops over the next few days, mirroring the extremely rapid test series observed in February with the first completed Raptor engine.

If all proceeds nominally, it’s possible that SpaceX could begin untethered hop tests in the near future. Regardless, this marks an excellent step forward for the company’s next-generation Starship/Super Heavy spaceship and launch vehicle – all data gathered in this phase will help to optimize and improve the final design of the first orbital vehicles.

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Disappearing Act

And new satellite imagery taken by Planet Labs reveals that the launch pad at the Imam Khomeini space launch center is a lot worse for the wear after …

It’s a flood of apocalyptic proportions! No I’m not talking about Noah and the ark, or even Offut Air Base.

Hi, I’m Grace Liu. Here’s your local Iranian weather for the week.

*walks in front of green screen*

The skies over Semnan in north-central Iran were mostly cloudy, with significant rainfall on March 20, 21, and again on the 26th.


*wildly gestures around greenscreen*

Thi weather radar map also shows precipitation around Semnan on the 26th.

Source: Ventusky

Why am I showing you the weather from Semnan in late March? Because that’s where Iran’s Imam Khomeini Space Center is located. And new satellite imagery taken by Planet Labs reveals that the launch pad at the Imam Khomeini space launch center is a lot worse for the wear after the downpour.

There is a small, circular launch pad at the space center that has been used for many of Iran’s satellite launches. Most recently, Iran attempted to launch a Safir space launch vehicle on Feb 5. It reportedly failed.

The circular pad usually looks like a colorful jawbreaker that a child has been licking for a day or two.

*more gesturing at the greenscreen*

In a recent image from March 29, the pad is barely visible.

Strong rains over the past two weeks likely flooded the thin sand around the area and deposited the sediment across the flat concrete.

This likely means that the launch pad is out of commission for now. Before the pad can be used again, the Iranians will have to take time to remove the sediment from the pad and possibly make repairs if there was any significant damage.

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SpaceX’s Starship hopper steps towards first hop with several cautious tests

SpaceX’s team of South Texas engineers and technicians have dived into a program of critical pre-hop tests of the first assembled Starship prototype, …

SpaceX’s team of South Texas engineers and technicians have dived into a program of critical pre-hop tests of the first assembled Starship prototype, a partial-fidelity vehicle – known as (Star)Hopper – meant to soon perform low-altitude, low-velocity hop tests powered by Raptor.

Despite a lack of official information is known and SpaceX’s general silence – even to local residents – about Starhopper’s testing, some barebones insight can be derived from what has and hasn’t been done or seen over the past seven days of testing, as well as five apparent wet dress rehearsals (WDRs). To verify the operational integrity of Starhopper and iron out best practices for what is effectively a one-off mobile test stand for Raptor, these WDRs (and one more active test) have seen the unusual prototype filled with some amount of liquid oxygen and methane propellant, taken to flight (hop?) pressures, and generally monitored closely to gather valuable telemetry and judge Starhopper’s condition and hop-readiness. Aside from Hopper, these tests also serve as a shakedown for complex pad and support facilities sprung up from a dirt pile in barely three months.

Here are a few photos from today. In addition to not being a rocket scientist, I am not a photog either. The close up of the rocket at the @SpaceX site was taken minutes after they reopened the road.

— Mark Reagan (@RGVReagan) March 27, 2019

Fueling the beast

Starhopper’s five (ish) wet dress rehearsal tests have demonstrated an intriguing level of caution relative to the last few months of BFR program development. Depending on how much propellant SpaceX has been filled the vehicle with and how much of that propellant they are able to recycle after each attempt, each dress rehearsal could cost upwards of six figures (USD), while also putting the unusual steel structure through multiple stress cycles.

No official info has been provided beyond a brief indication that SpaceX means to static-fire Starhopper before transitioning to tethered hops, meaning that it’s quite difficult to determine what exactly the testing plan and schedule are. In other words, these ~5 WDR tests could have been the plan all along, or each test could be producing data that has lead launch engineers to scrub Raptor ignition attempts nominally planned at the end of each rehearsal. For an entirely new and unfamiliar design like Starhopper, it seems likely that at least one or two WDRs were planned before any attempt to static fire the hopper’s lone Raptor, although it could also be the case that – much like most SpaceX static fire attempts – the WDR was simply built in as a precursor to ignition, barring off-nominal telemetry.

Local resident and spaceflight forum-goer /u/bocachicagal captured this excellent video of Starhopper’s most active test yet, perhaps the ignition of Raptor’s preburner. (NASASpaceflight – bocachicagal)

The third and most visibly active test yet (above) occurred on March 25th and saw Starhopper briefly vent a cloud of gas from Raptor, with some viewers guessing that a Raptor preburner (partial ignition) test had been observed. It’s unclear whether this Raptor (SN02, the second produced) completed acceptance testing in McGregor, Texas on the way from California to Boca Chica. If not, then the caution on display in these WDR tests (i.e. no visible Raptor ignitions) could also be a side-effect of extremely young age of the full-scale engine test program, known (publicly) to have only completed a couple dozen seconds of hot-fire testing in February.

The fidelity of Starhopper relative to its orbit-facing successors is also unclear. If the prototype’s structures, avionics, and plumbing are actually more indicative of the finished product than they appear, it’s possible that SpaceX tendency towards accepting the destruction of test hardware is in a bit more of a cautious state than usual, with a total loss of vehicle amounting to a significant technical setback and schedule delay. Based on the vehicle’s appearance and the apparent decision to entirely set aside the idea of installing a new fairing on Starhopper, it seems far more plausible that the prototype is more of a glorified mobile test stand for Raptor engines and Starship avionics (software) than anything else.

Test today has been postponed until tomorrow, #SpaceX crews hard at work today on the #StarHopper & progress on the orbital #StarShip. 🚀


— Austin Barnard🚀 (@austinbarnard45) March 26, 2019

If Starhopper really can’t function as something more than a marginally mobile test stand for Raptor(s), then the value of actually hopping the craft could be quite minimal, perhaps offering useful data on Raptor’s control loop and behavior during flight operations. Still, CEO Elon Musk has stated several times that SpaceX has gotten good enough at the actual task of landing rockets vertically that it’s effectively a known quantity for Raptor and BFR, whereas the exotic atmospheric operations planned for Starship are the main uncertainty for successful recoveries.

Simultaneously, SpaceX is building the first orbital-class Starship prototype just a few thousand feet away from Starhopper’s new roost, utilizing stainless steel sheets almost three times thinner than the quarter-inch-thick steel the first prototype was built out of. It’s likely that Starhopper’s career will thus end up being rather short, given that the completion of the first near-final Starship would further minimize the low-fidelity hopper’s utility. If it’s actually meant to reach orbit, the newest Starship prototype will require the tripod fins and canard wings shown in SpaceX’s latest renders in order to safely land for future test flights, while Starhopper appears to be far too heavy and simplistic to warrant the expensive and time-consuming task of outfitting it with aerodynamic control surfaces and a new nose cone capable of surviving the associated forces.

Starhopper conducts one of its first wet dress rehearsals in Boca Chica. On the right is a flare stack, used to burn off unused methane. (NASASpaceflight – bocachicagal)

While additional testing may be done on Friday, March 29th, it appears that the next attempts for the first static fire (and hop tests) will begin next week (likely Monday) – SpaceX is unlikely to test on weekends due to the potential disruption it could cause for beach-going locals.

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Air-Breathing Rocket Engine Promises Future Space Planes

After all, man had just walked on the moon and suborbital transports could make the same trip in 30 minutes and — according to Elon Musk — go …

If you are a certain age, you probably remember the promise of supersonic transports. The Concorde took less than 4 hours to go across the Atlantic, but it stopped flying in 2003 and ended commercial supersonic passenger flights But back in the 1970s, we thought the Concorde would give way not to older technology, but to newer. After all, man had just walked on the moon and suborbital transports could make the same trip in 30 minutes and — according to Elon Musk — go between any two points on the Earth in an hour or less. A key component to making suborbital flights as common as normal jet travel is a reasonable engine that can carry a plane to the edge of space. That’s where the UK’s Sabre engine comes into play. Part jet and part rocket, the engine uses novel new technology and two different operating modes to power the next generation of spaceplane. The BBC reports that parts of the new engine will undergo a new phase of testing next month.

The company behind the technology, Reaction Engines, Ltd, uses the engine in an air-breathing jet mode until it hits 5.5 times the speed of sound. Then the same engine becomes a rocket and can propel the vehicle at up to 25 times the speed of sound.

The engine has three sections: The front end is a precooler that can take a 1,000C airstream and chill it to -150C almost instantly. The core engine then takes air from the precooler, and forces it back out through relatively conventional rocket nozzles.

Although a company called Boom is trying to revive interest in supersonic jetliners and GE has new engines for the purpose, a commercially viable suborbital transport could obsolete supersonic transport. Reaction Engines is a private venture, backed by BAE, Rolls Royce, and Boeing. It also has research and development help from the British government. The history behind supersonic flight is interesting and perhaps will extend to cover the X-59, soon.

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DeepSpace: Rocket Lab ready for first commercial launch of 2019, an innovative DARPA spacecraft

Completed on March 8th, SpaceX’s near-flawless Crew Dragon launch, space station rendezvous, and recovery is likely the last of the company’s …

This is a free preview of DeepSpace, Teslarati’s new member-only weekly newsletter. Each week, I’ll be taking a deep-dive into the most exciting developments in commercial space, from satellites and rockets to everything in between.

If you’d like to receive this DeepSpace newsletter and all of our newsletters and membership benefits, you can become a member for as little as $3/month here.

Now approximately four months distant from the inaugural commercial launch of Rocket Lab’s Electron rocket, the company is ready – following many weeks of customer-side delays – to conduct its first launch of 2019, aiming to place an experimental DARPA-funded satellite into low Earth orbit (LEO).

If all goes as planned with the launch and experimental spacecraft’s orbital operations, Defense Advanced Research Projects Agency (DARPA) hopes to use the mission to qualify a currently-untested technology that could ultimately enable the production of massive communications and sensing antennas that can fit on relatively tiny satellites. Known as R3D2 (ha…ha…), the mission also effectively serves as the latest operational debut of DARPA’s growing interest and involvement in spaceflight-related industries, nominally proving that the agency is capable of leaning on established companies and startups to rapidly design, build, and fly satellites. Barring any additional launch delays from DARPA’s preparations, Rocket Lab hopes to launch Electron around the end of this week – likely March 22-24 – to kick off what will hopefully be a busy and productive year for the newly operational launch provider.

DARPA in Space

  • Originally targeted for sometime in the second half of February, the R3D2 mission – Electron’s fifth planned launch in 18 months – has suffered several weeks of delays due to issues faced by DARPA during satellite delivery and pre-launch preparations.
    • Aside from a general hint that the satellite arrived a few weeks later than planned and an official statement from Rocket Lab that “DARPA’s payload team is conducting final ground station configuration work over the coming days”, the process appears to be going rather smoothly.
  • Weighing in at roughly 150 kg (330 lb), the R3D2 spacecraft – barring the quiet inclusion of co-passengers – will be the first launch of Electron dedicated to a single satellite. In fact, 150 kg is actually the maximum listed payload that Electron is capable of launching to a 500 km (310 mi) sun-synchronous orbit (SSO), providing a functional ‘ceiling’ for the ultimate destination of DARPA’s satellite.
    • R3D2’s primary purpose will be to extensively test a brand new antenna technology and thus prove (hopefully) that the in-space deployment mechanism and unique material composition function as designed. Likely no more than 1-2 feet (~50 cm) across, the definitively small satellite will attempt to deploy an antenna many times larger than itself.
    • Made out of a material known as Kapton, the deployable antenna will reach a maximum diameter of 2.25 m (7.4 ft), fairly large even when compared with antennas used on satellites many dozens of times more massive.

Rocket Lab’s Biggest year yet

  • Although the company is off to a relatively slow start, as many as eleven Electron missions – including R3D2 – are at least tentatively manifested for launches in 2019.
  • In November and December of 2018, Rocket Lab further demonstrated that it is more than capable of a respectable monthly launch cadence, particularly impressive for a rocket conducting its third and fourth missions ever. If Rocket Lab can more or less sustain that cadence after DARPA’s R3D2, the company could ultimately complete as many as 8-10 launches this year.
  • Ultimately, founder and CEO Peter Beck says that Rocket Lab and Electron will eventually target dozens of annual launches per year and a weekly launch cadence from an array of launch facilities.
    • Earlier this year, Rocket Lab officially announced that it had come to an agreement with the state of Virginia to build its second launch complex (LC-2) at Wallops Flight Facility (also known as the Mid-Atlantic Spaceport). If construction proceeds apace, the company’s first US-based Electron launch could occur before the end of 2019.
Rocket Lab’s Electron – built almost entirely out of carbon fiber composites – is an undeniably spectacular rocket, building heavily on New Zealand’s unique global expertise in high-performance composites, an offshoot of a very healthy sailing industry. (Rocket Lab)

  • DARPA’s goal with R3D2 – and its interest in space and small satellites in general – should ultimately benefit the entire spaceflight industry, potentially paving the way for the design and production of small satellites with technical capabilities that far outstretch their compact nature.
    • Reliable and affordable deployable structures are becoming a growing focus of a number of young and old spaceflight companies, ranging from heavyweights like SSL/Maxar to new startups like Oxford Space Systems.
  • Unlike most modern defense and aerospace technology procurement, DARPA is also distinctly focused on streamlining the process of designing, building, and launching spacecraft. To do so, the agency plans to rely heavily on established commercial entities to optimize speed and affordability will still ultimately producing innovative space systems and pushing the state of the art forward.
  • Aside from closely involved projects like R3D2, DARPA – through a program called Blackjack – is also extremely interested in a number of LEO communications constellations proposed in the last few years by companies like SpaceX, OneWeb, and Telesat, and has already awarded a series of small contracts with several to begin the program’s earliest phases.

Mission Updates

  • Completed on March 8th, SpaceX’s near-flawless Crew Dragon launch, space station rendezvous, and recovery is likely the last of the company’s orbital launch activities for the month of March.
  • The second launch of Falcon Heavy – the rocket’s commercial debut – is currently expected to occur as early as April 7th
  • After Falcon Heavy, SpaceX has at least one other launch – Cargo Dragon’s CRS-17 resupply mission – firmly scheduled for April (April 25th), as well as the more tenuous possibility of the first dedicated Starlink launch occurring as early as late April.

Photos of the Week:

NASA posted a series of official photos documenting SpaceX’s Crew Dragon recovery process following the spacecraft’s first successful orbital reentry and splashdown. The photo below (top) offers one of the best (and most detailed) views ever made public of one of the heat shields of a SpaceX Dragon spacecraft, offering a glimpse of the wear the PICA-X material experiences after several minutes of extreme heating and buffeting. (c. NASA/Cory Huston)

Back on land, SpaceX’s South Texas entourage has continued to build the first full-scale Starship prototype – nicknamed Starhopper – in preparation for the vehicle’s inaugural static-fire and hop tests. According to official SpaceX statements, those tests could occur as early as this week, partially confirmed by the first installation of a Raptor engine (serial number 2) on a flight article of any kind.(c. NASASpaceflight – bocachicagal)

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