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.

YEET! Launching Starship has a huge learning curve. Thanks @elonmusk for a spectacular day! @austinbarnard45 #SpaceX #BocaChica #Texas #Starship pic.twitter.com/PC0p3tFfsB

— LabPadre (@LabPadre) February 2, 2021

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:

We were too dumb

— Elon Musk (@elonmusk) February 4, 2021

Before clarifying the fix needed to avoid such a repeat:

It was foolish of us not to start 3 engines & immediately shut down 1, as 2 are needed to land

— Elon Musk (@elonmusk) February 4, 2021

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:

Yeah. By default, engine with least lever arm would shut down if all 3 are good.

— Elon Musk (@elonmusk) February 4, 2021

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.

Possibly the last sunrise with Starships SN9 and SN10. It looks like a beautiful day for a flight. ????@NASASpaceflight pic.twitter.com/zgUMnUduP7

— Mary (@BocaChicaGal) February 2, 2021

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.