Tuesday, 29 December 2020

Beginning a New Normal

Since this is being written in the sixth month of the COVID19 "Pandemic" you may think I am going to write about this subject. 
You would be wrong.
The new normal that began Aug.4/2020 refers to the successful launch of the SpaceX SN-5 prototype rocket from Boca Chica build /launch site in Texas.
This roughly welded, stainless steel shell is actually the most sophisticated of a new class of spaceships, transportation systems, launch vehicles envisioned by 21st century technology.
While most of the other launch systems are like very expensive mortars designed to toss items into space, never to fly again, this Starship is designed as a method to enter and return from space, intact and ready to fly again, and again, up to 20 or more times, before being refurbished.
The era of throwing a 100 million dollar first stage booster into the ocean as trash after every launch is over.  When SpaceX perfected the Falcon 9 booster as a returnable, re-flyable rocket it was considered a success but it was only a start of something much more daring.
To return a booster which is empty, relatively light and only travelling 10 times the speed of sound, from a height of 40 miles, had never been attempted BUT had been thought possible.  The engineers of five countries who crunched the numbers, weighed the costs and decided that the alternative was correct were always employed by governments with excess tax dollars to spend. So they threw away billions of dollars worth of high tech engines, tons of aluminum and kept producing inefficient launch vehicles.  
To return an orbiting spacecraft, with a speed almost 40 times sound speed,  that is almost the the same mass as when it launched is 3 orders of magnitude more difficult.  This is the engineering feat that SpaceX will be attempting with the new Starship when they have gone through the early suborbital flights.
The SN-8 prototype is set to launch in early November to a 15 mile height and attempt a soft landing back at the launchsite.

Now on Dec.29th I can relate that SN8 did launch from Boca Chica on the 9th of Dec.  It rose on 3 engines and reached the planned altitude at 47,000 ft, shut down the engines, rotated to horizontal and floated down and back to the landing zone; one engine was lost due to low fuel pressure and the landing ended in an explosion of the rocket.  99% successful but the next SN9 is already on the launchpad, set to go in a week or so.

Now it's Feb. 14th/2021 and the SN-9 was flown on Feb. 2nd to an altitude of 40,000 ft. and managed to 'fly' back to the launch site and flip from horizontal to almost vertical before an engine failure caused a second crash of a prototype.  But SN-10 is on the launch pad ready to go, and SN-11 is finished and ready to move to Pad -B.

This is added on Sept. 23/2021. The SN-10 flew successfully but exploded above the landing zone in a heavy fog.  However SN-11 was partially successful.  Landing with a little too much speed, standing upright but with a fuel leak from a ruptures line which caught fire and blew up the rocket.
SN-12, 13, and 14 were passed by and SN-15 flew a faultless test and landed safely.  It was decided not to try a re-flight so that they could press on to a full booster and Starship launch next.  So now we await the next chapter.