Starship SN10 – The Muskette https://themuskette.com Thu, 04 Mar 2021 23:04:37 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.2 https://themuskette.com/wp-content/uploads/2022/12/cropped-elon-fav-32x32.png Starship SN10 – The Muskette https://themuskette.com 32 32 Starship Just Had Its Biggest Achievement Yet https://themuskette.com/starship-just-had-its-biggest-achievement-yet/ https://themuskette.com/starship-just-had-its-biggest-achievement-yet/#respond Thu, 04 Mar 2021 23:04:37 +0000 https://muskette.com/?p=3205 On March 3, Starship SN10 conducted its high-altitude flight and achieved more than any prototype had done so far. 

If you haven’t watched the flight already, take some time out of your day, it’s worth it:

 

Launch & Ascent

At 17:15 CST, Starship SN10 lifted off Pad A at the Starship Launch Site in Boca Chica, Texas. This came after an aborted attempt earlier in the day, whereby the vehicle’s computers commanded shutdown at T-0.1 seconds due to excessive thrust generated by the Raptor engines. 

Elon took to Twitter to tell us they would re-attempt a launch after tweaking the parameters of the flight computer:

And thus, the re-attempt at 17:15 was a go by the flight computer, and SN10 soared into the skies.

We saw a stable ascent, initially powered by all three Raptor engines, before shutting them down in sequence. This was to keep the thrust-to-weight ratio from being too high, and allowed for a stable, controlled ascent to 10km in altitude. 

The Raptors gimbaled (pivoted) in order to maintain control, whilst individual engines were throttled down and eventually shut down. 

Until finally, the vehicle relied upon a single-Raptor engine, providing the final acceleration to 10km. A ‘kick-flip’ maneuver was then performed by the Raptor before being shut down, to re-orient the vehicle belly-first. 

Descent & Landing

With the use of the forward and aft flaps, electrically powered by Tesla motors, SN10 had a stable descent from 10km, once again verifying the concept of the controlled ‘belly-flop’. 

A key moment in the flight was during the landing phase, something SN8 and SN9 had failed on for differing reasons. As talked about in another article, SN10 combined the improvements of SN8 and SN9, in the hope that it could land in one piece. 

And it did just that. 

We saw all three Raptor engines re-ignite successfully, a flip maneuver from horizontal to vertical, and the successful shutdown of two Raptors relying on one to perform the final touchdown. 

And touchdown it did. 

This was the first time a Starship had completed a high-altitude test flight, and landed. We had seen small hops in the past, but nothing as ambitious as this, and we had seen two previous prototypes have a failed attempt at touchdown. 

SN10’s landing marked a truly historic event in Starship development. 

Post-Landing

As everyone in the space community lost their minds, Starship SN10 decided to give one more surprise. 

Reflection

Even though SN10 had landed, it didn’t do so in the smoothest way. Nor did the landing legs deploy as best they should. 

You can visibly see SN10 touching down at a relatively high velocity, to the point where the entire vehicle appeared to bounce on the landing pad. 

Whatever landing legs were deployed correctly, they would’ve likely been crushed by this higher-than-expected landing speed.  

Somehow, the vehicle did manage to remain standing.

But the explosion we saw shortly after was likely due to the fireball we could see being emitted out of the shutdown engines during the landing burn. 

By the looks of things, this could have been leaked methane being combusted by oxygen, the leak source likely being a shutdown Raptor(s).

As the vehicle sat on the landing pad, enclosing the entire engine bay, this fireball continued to rage inside to the point of the liquid oxygen tank being ruptured and ignited. 

SN10 is now a wreck of stainless steel, just like SN8 and SN9 was.

But unlike them, this prototype had gone further than any prototype had gone before and was a huge achievement. 

What’s Next?

Starship SN11 is up next, and will likely conduct a repeat of this high-altitude test, this time landing intact. 

Teams will be hard at work looking through data, and adding improvements wherever needed. The ultimate fate of SN10 came down to the landing velocity being too high, potentially because one or more of the Raptors underperformed. 

Whatever occurred, SpaceX will be seeking a fix, and that fix will be applied to SN11.

]]> https://themuskette.com/starship-just-had-its-biggest-achievement-yet/feed/ 0 Could Starship SN10 Be the Successful One? We Await an Answer https://themuskette.com/could-starship-sn10-be-the-successful-one-we-await-an-answer/ https://themuskette.com/could-starship-sn10-be-the-successful-one-we-await-an-answer/#respond Wed, 24 Feb 2021 21:12:18 +0000 https://muskette.com/?p=3179 SpaceX’s Starship development has caught the attention of many across the world, particularly after the spectacular flights of SN8 and SN9, both of which ticked multiple objectives for the vehicle and its radical design.

Overall, they were renowned successes, and created interest like I’ve never seen before in the spaceflight community. However, both vehicles failed on one crucial objective; landing.

But both instances have exposed failure points in the vehicle, something SpaceX have recognized and resolved. SN8 exposed an autogenous pressurization issue in the header tanks, now resolved by using helium to pressurize them. SN9 exposed a Raptor ignition flaw, which has now been resolved through redundancy mitigation in the landing burn.

The point being, existing failure points have now been resolved. At face value, if no more failure points crop up, there’s nothing that should stop SN10 from finishing the job SN8 and SN9 couldn’t quite achieve.

But rocketry is never that simple.

What’s SN10 been up to?

Starship SN10 took its place on Launch Pad A on January 29, alongside SN9 on Pad B, marking the first time we saw two Starships together at the launch site.

SN9 took flight four days later on February 2. In its aftermath all eyes were on SN10, and as usual with Boca Chica operations, its testing campaign was imminent already.

Unlike SN9, SN10 did not have its trio of Raptor engines installed prior to pad transport. Elon said this would happen after it completed its cryo test:

But as ever with Starship operations, plans change constantly so during the first week of January, the three Raptors were installed before the cryo.

And before long, the testing campaign begun with a cryogenic proofing test (cryo test) whereby the vehicle was loaded with superchilled liquid nitrogen to verify structural integrity.

This was completed on February 8, just six days after SN9’s flight.

Following the cryo test, a static fire was expected as usual, where the vehicle is held down but all three Raptor engines are ignited for a few seconds qualifying a multitude of hardware on the prototype, ready for flight.

Static fire occurred on February 23.

The static fire appeared to be a good duration, but as I outline, the rapid depressurization venting after shutdown hasn’t been a good sign in past static fires.

This vent releases all pressure from the liquid oxygen and liquid methane tanks, and allows for detanking to occur whereby the propellants can be withdrawn or boiled-off from the tanks. This naturally happens at the conclusion of a test, in order to safe the vehicle and allow work to continue at the pad.

But, to see it directly after the shutdown of engines usually signals an abort has occurred. The vehicle’s computer has detected an anomaly, and it seeks to safe the vehicle as soon as possible.

Usually, we have seen them withhold from detanking until a few minutes after the static fire, likely for data collection post-ignition. This is without computer intervention in the form of an abort.

Elon confirmed this shortly after:

As of present, a new replacement Raptor has been delivered to the launch site and will be swapped out with the anomalous one.

In keeping with past experiences, another static fire is highly likely.

This should hopefully be completed in the coming days, potentially more than a week.

The flight of SN10

In the aftermath of the first static fire, a flight depends on a successful second one and favorable weather.

At present, there are launch Temporary Flight Restrictions (TFRs) set for Thursday, Friday and Saturday (February 25, 26, 27), combined with road closures on Thursday, Friday, Monday and Tuesday (February 25, 26, March 1, 2).

As ever with these dates, they can change very easily. The bottom line is that a more solid estimation can be given once there is a nominal static fire, which we’re yet to have.

In regards to Federal Aviation Administration (FAA) approval for launch, there are no hurdles to jump.

How will SN10 make a success out of SN9’s failure?

As discussed in my other article, SN9 failed to land due to an anomalous Raptor failing to ignite on the landing burn. More detail on mitigation can be found there.

Since, NASASpaceFlight understand that incident was down to an “apparent ignitor issue” in the engine. This is unconfirmed, but the best indicator we have of the incident as there has been no official news.

According to Elon himself, these are the chances that SN10 will land:

Best of luck SN10, as always, we will be watching whatever the outcome.

]]> https://themuskette.com/could-starship-sn10-be-the-successful-one-we-await-an-answer/feed/ 0 SpaceX Continues to Press Ahead Onto SN10 at Astonishing Pace https://themuskette.com/spacex-continues-to-press-ahead-onto-sn10-at-astonishing-pace/ https://themuskette.com/spacex-continues-to-press-ahead-onto-sn10-at-astonishing-pace/#respond Tue, 09 Feb 2021 00:02:33 +0000 https://muskette.com/?p=3150 Starship SN9 had its long-anticipated 10km test flight on February 2 2021, resulting in the completion of numerous test objectives, but the eventual destruction of the prototype during its failed landing attempt.

Liftoff occurred at 14:25 CST, powered by three Raptor engines, SN9 soared into the skies of Boca Chica, Texas, with millions of people across the world watching in awe.

Similar to SN8’s high-altitude test flight, we saw the vehicle shutdown individual Raptors in sequence to adjust the increasing thrust-to-weight ratio as the vehicle’s weight decreased by propellant use.

The vehicle eventually relied upon one Raptor as it reached its apogee of 10km, executing precise control as the vehicle began to slow toward a hover, before the engine eventually performing a ‘kick-flip’ helping reorient the vehicle belly-first, then shutting down.

Once again, we saw amazing stability through the use of the vehicle’s forward and aft flaps, helping steer the craft back toward the launch and landing site whilst keeping oriented.

SN9 was on-profile, at terminal velocity and right over the landing pad, preparing to reignite two Raptor engines to flip vertical, and touchdown. However, we could visibly see one Raptor reignited successfully, but the other failed to.

What resulted was the vehicle successfully flipping, but uncontrollably. Without enough thrust to counteract the over-flip, the vehicle could not maintain vertical, let alone scrub off enough velocity for a soft touchdown.

SN9 crashed spectacularly.

The resulting hours and days allowed speculation to run wild; SpaceX eventually confirmed in a statement that “one of the Raptor engines did not relight and caused SN9 to land at high speed and experience a RUD.”

Significantly, Elon Musk took to Twitter to answer a question many had on their minds:

Before clarifying the fix needed to avoid such a repeat:

Prior to SN9, the landing burn consisted of using two Raptor engines, configured parallel to the flaps, to perform the flip-to-vertical manoeuvre, before then shutting down to one Raptor for the touchdown.

SN9 highlighted the lack of redundancy to this method, whereby if one of the Raptors failed, the landing would fail. Elon clarified even further the fix they will now use:

By igniting all three Raptors, flight computers will carefully monitor the health of all-three to which if nominal, one will shut down leaving the required two to perform the remaining burn. However, if one is off-nominal, by having all three Raptors pri=med, the opportunity to maintain the use of two Raptors remains, and thus the chances of a successful landing are not lost.

Onto the Next Prototype

Starship SN10 was already on the pad before SN9 launched, providing a glimpse of the first time two Starships had been on the pad together.

Fortunately, the crash landing of SN9 did not affect SN10 and according to local sources, the prototype sustained no damage from debris.

In the aftermath of SN9, and the clear impression that SpaceX had a fix, it was widely thought SN10 could be seen in the skies very soon. This consensus has stuck.

As of February 8, the prototype has undergone a cryogenic proofing test whereby the vehicle’s tanks were loaded with liquid nitrogen qualifying the vehicle’s capability to hold superchilled propellant.

A static fire will be conducted shortly after to qualify the three Raptor engines, in which if successful, there’s a high probability for a flight by the end of February, if not sooner.

The speed of Starship development and testing is truly phenomenal. SN11 is undergoing final checks, and will soon be rolled out to the pad, amongst a multitude of other prototypes in construction, that will shortly follow.

Truly phenomenal speed.

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