SpaceX launches Starship, but loses rocket signal – 11/18/2023 – Science

SpaceX held this Saturday (18) in Boca Chica, Texas, the second launch of its Starship vehicle — but it was almost as if it were the first, and there was no lack of excitement.

For the first time, it reached space, with the second stage reaching an altitude of 150 km. However, it probably exploded, and contact was subsequently lost, without completing the almost orbital trajectory that would take it to re-entry near Hawaii, in the Pacific Ocean.

The launch represents considerable progress since the first flight in April. However, it still brings challenges that Elon Musk’s company will have to overcome to make the most powerful rocket ever built in history operational.

First, the good news: takeoff took place without major disturbances, shortly after 10 am (Brasília time), and for the first time the 33 engines of the first stage worked satisfactorily, giving the vehicle a safe ascension. In the previous attempt, several of them had failed in flight, preventing them from reaching space.

This time, the separation of the stages also happened successfully, with around three minutes of flight, as expected. But a surprise came soon after, when the first stage exploded rather than making a powered return into the Gulf of Mexico.

The second stage continued its climb to almost orbital speed, reaching over 24,000 km/h (to enter orbit, it takes around 27,000 km/h), before the control center lost contact with the vehicle. . It is not known at the moment what would have happened, but it is likely that it was destroyed.

It’s a rather bland ending to the flight, but not entirely unexpected. The whole logic of adopting a “near-orbital” flight is to ensure, in these early stages of rocket development, that it quickly re-enters the atmosphere even if control over it is lost.

It’s all part of the design philosophy dictated by Musk, which favors flight testing, even using unrefined prototypes with no guarantee of success. The results obtained from the experiments will be used to guide modifications to the vehicles with each new attempt.

It is also true that there will be pressure on SpaceX to deliver results, as the Artemis 3 mission, scheduled to take astronauts to the surface of the Moon in the second half of the decade, depends on the availability of Starship. The company hopes to carry out a new flight at the beginning of next year, but this will once again depend on authorization from the FAA (the agency that regulates civil aviation and commercial rocket flights in the USA).

SpaceX had to slow down its development pace in recent months while waiting for authorization from the FAA to return to launches, but with the agency’s approval granted last Wednesday (15), the company should speed up testing again.

SERIES MANUFACTURE

A good clue as to how SpaceX’s development scheme works, in contrast to the traditional space industry, is the numbering of the vehicles used in flight. In the first orbital scale flight attempt, which took place on April 20, Booster 7 (first stage) and Ship 24 (second stage) flew. The numbering indicates how many prototypes of each were developed (and sometimes built) before those that flew. Previous versions served to improve the design, manufacturing and ground testing of some of the systems, in addition to conducting high-altitude flights of the second stage, with subsequent landing.

For this second flight, we had Booster 9 and Ship 25, which, according to Musk, include more than a thousand modifications compared to those used in the previous takeoff, in April.

At that time, SpaceX treated it as a success if the launcher left the platform without destroying it – which in fact happened. The flight was far from reaching Earth orbit, however, ending untimely about four minutes after launch, with the failure of several of the first stage’s engines. Now, with the improvements, Musk estimated the chance of orbiting the Earth at 60%. That didn’t happen, but barely.

Some of the changes were implemented to meet FAA demands, others are natural improvements to systems that were already foreseen even before the first flight.

Among the biggest innovations successfully introduced were a new “hot” stage separation system (in which the upper stage engines are activated before separation), a technique little used in American vehicles, but more common in Russian rockets, and a new electronic steering control system for the first stage nozzles, in order to better control the rocket’s trajectory. The self-destruct system was also upgraded, as the previous device failed on the first flight.

In the ground systems, there were also major upgrades, the most notable of which was the installation of a water deluge system, to cool the platform during the takeoff process. This time, there was much less debris resulting from the firing of the engines.

The telemetry data will still be analyzed in the coming days to find out exactly what went right and what went wrong on this second flight. The fact is that many technologies will still need to be demonstrated before Starship is ready to take astronauts to the Moon, such as the ability to recover both stages of the vehicle, as well as to perform refueling in orbit. More than a hundred Starship launches are expected to be made before anyone can board it for a spaceflight.