C'mon people! It's not like this is rocket science.
Oh. Wait. Actually, it is.
Lover Boy and I spend a lot of time watching his younger sister while their father is away on business. Last weekend she came over to the house with her laptop, as she usually does, but instead of working on school projects or poking around the internet she started playing a game called, Kerbal Space Program.
Kerbin is a fictitious blue-green world not unlike our own save for the facts it is only 600km in radius and it has 2 moons. Kerbin is inhabited by Kerbals, little green humanoids with large, curious eyes and an endearing stoicism in the face of near-incessant catastrophe. The object of the game is to get Kerbals off of Kerbin and into space.
To meet these objectives the player is provided with a library of parts from command modules to fuel tanks, engines, solar arrays, landing gear, etc. etc. etc. With these basic elements you can build rockets, satellites, space stations and even space planes.
It's not as easy as it looks, she explained, as her rocket climbed into the air. She went on to describe how she lost many rockets -- and no small number of Kerbals -- from designs that veered -off course out of control or simply exploded on the launch pad under their own weight. Simply achieving orbit is a feat in and of itself as you have to begin your gravity turn at the right altitiude, which is wholly dependent on your rate of ascent which in turn depends on the mass of your rocket and the power of your engines.
"Well of course. Everyone knows that," I said to my husband who gave me a bewildered shrug.
Her target today was Minmus, the second of Kerbin's two moons. This was an unmanned (unkerballed?) flight as she prefers to send probes ahead of the more deliberate missions. Having easily achieved orbit (?!?!?) she waited until the rocket circled around to periapsis, the lowest point of orbit (the converse being apoapsis) where she had set a maneuver node.
As she approached periapsis she aimed the nose of the rocket towards the point designated by her maneuver plot and when the prograde vector overlapped it she hit the main engine. Checking the map she watched as her projected course brought her into an encounter with the Mun's (the nearer moon of Kerbin) gravity.
Seconds ticked away as a green gauge next to the navigation ball bled away. This was the Delta V indicator, the amount of thrust to be applied to change the velocity and hence, the trajectory. Delta is apparently the mathematical symbol for "change" and V is for velocity. When the indicator hit 0.3 she shut down the engines.
Satisfied she switched from the map to the free camera mode which showed the rock leaving Kerbin orbit. It was simply beautiful to watch as the tiny, beautiful world grew smaller and a glorious universe unfolded. It may just be a game but my heart was seized by the silent splendor of it all.
She accelerated time as the trajectory required a 4 hour, 50 minute time until Mun encounter. Along the way, she explained she would be approaching the Mun from behind so as to gain acceleration and thus conserve fuel. If she were to approach from the front she would decelerate and that would jeopardize the mission.
She also switched to another mission, one that had landed successfully on the Mun. She showed how Jebediah Kermin, her personal favorite due to his happier nature, could walk around the in the Mun's much lower gravity.
Back to following the probe she waited for the Mun to capture the tiny machine in its sphere of influence. She quickly placed another maneuver node and fired the engines at the appropriate time for the prescribed duration. Again, the trajectory plot grew until it changed color indicating a projected encounter with Minmus. She switched back to camera mode as we watched the Mun recede off into the distance.
As we again waited for time to elapse she told me how she wanted to get a space station in orbit around each moon but, she lamented, docking was a skill she had yet to master even though she had watched numerous video tutorials. It seemed an odd confession considering the ease and confidence at which she commanded her current mission.
In time she approached Minmus. She rotated the probe to a retrograde position and fired her engine until the last of its fuel was depleted. She turned the probe prograde vector before releasing the spent rocket stage ensuring it drifted away from behind rather than being in the way ahead of her as she tried to decelerate -- a lesson she assured me she had learned the hard way. She returned the ship to its retrograde course and began burning her final engine to bring her orbit in around the Minmus.
It is a strange and uninviting world of teal blue ice oceans surrounded by menacingly huge white mountains of ice. Bit by bit she worked to lower her orbit. She wondered aloud whether she should attempt a soft landing.
"I think I'll try it!" she announced like one who had no government budget to be mindful of.
Continuing the retrograde burn she slowed the rocket until gravity took over. Then it was a matter of juggling engine burn while toggling the stabilizing system on and off. Her little fingers worked furiously to control thrust and position but -- I am sad to report -- there were too many unlearned variables. Altitude, the jutting terrain, limited fuel and unfamiliar gravity conspired to dash her ambitions and her rocket against the mountains of Minmus.
A cathartic "Darn it!" later and she was back in the Vehicle Assembly Bay with a handful of lessons learned, redesigning her satellite.
She then announced she wants to be an astronaut.
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Why does he remind me of Invader Zim?
(Tsiolkovsky rocket equation, via Wikipedia)
I'll never get anything done for playing that game now.
