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Tag Archive: Kerbin II
Jan 29 2021
Operations Summary – Weeks of 1/18 & 1/25/21
Jan 22 2021
Kerbin II Mission Analysis
In the months following our first orbital mission, which came very close to failing, lots of work was done on the Ascension Mk2 to make it more capable of reaching orbit. The result was a success on our second attempt, which placed the Kerbin II satellite into a stable and nearly circular orbit 191x228km@26° above Kerbin. Now that the hardest part of the mission was done, it was time to begin our first long-term operation of a spacecraft on orbit.
The Mission
The main goals of the mission in addition to telecom testing was just to see how the spacecraft fared over several weeks in space, in regards to things such as wear on its equipment to the stability of its orbit. It was equipped with two main antennas that each by themselves could get a strong signal to the ground for the transmission of science & telecom data and a tertiary backup antenna which could get enough of a signal to send & receive commands. This meant that potential loss of the satellite due to communications issues was unlikely. The probe core was constructed better than that of Kerbin I so although it remained a single point of failure it was at least robust. Whether the science instruments would last several weeks of space radiation exposure was also a question. Finally, scientists were still unsure if the 70km boundary to the atmosphere was “hard” or “fuzzy” – could an orbit remain stable or was there enough drag to gradually bring a spacecraft back down into the more well-defined atmosphere?
Dec 17 2020
Kerbin II
Nov 12 2020
Progeny Mk7-B Flight 3 Analysis
A pause after the first two launches was required to not only build the final two rockets but also to launch the second Ascension Mk2, which required a pad reconfiguration. The pad was setup again afterwards to support Mk7-B launches and the third rocket was trucked out to the pad to perform its mission, which we hoped would finally see the rocket on a high sub-orbital trajectory with a successful hot staging to avoid losing speed on ascent. While the launch date did not change, the rocket’s new 0.625m SRB was swapped out for a refurbished SRB to test under flight conditions for the first time after making it through two static fires.
The Flight
No delays occurred during pre-launch preparations and everything was looking good for an on-time lift off when a hold was called from the weather desk just 8 seconds prior to T-0. The mountain wave sensors were tripped and due to the high instability of the rocket without its support arms a hold had to be called before they were retracted at T-5s. No gusts were recorded at KSC in the following minutes however and after some more checking on the weather data it was determined to be a false alarm and the countdown was reset to T-2min with a new launch time of 18:00 local. The hold was released 29 minutes after it was called. T-0 arrived without further incident, all four support arms retracted properly and the Boostertron II first stage was successfully ignited to begin the ascent.
Oct 21 2020
Ascension Mk2 Flight 2 Analysis
Although the first orbital mission was eventually deemed a success for the payload, the Ascension Mk2 failed in its attempt to place the satellite it carried into a stable orbit. This brought the Ascension team back to the drawing board to improve the Viklun upper stage and make it more capable of maintaining attitude with its Reaction Control System cold gas thrusters. In the months since the first mission additional design work was also carried out for the next payload, dubbed Kerbin II and meant to test out technologies that would be used in the first line of communication satellites we are hoping to deploy in 2021. Once the Viklun stage improvements and payload design were finalized the rocket was assembled without issue in the VAB but the day before launch a problem occurred with installing the Radioisotope Thermal-electric Generator. The RTG was installed late in the launch preparation because the heat it outputs would compromise the fairings if left too long without thermal control, such as that provided by the crew access tower when the rocket is on the pad. Thankfully the problem was easy to overcome and the mission was only delayed to the following week.
The Flight
With no issues popping up during pre-flight the Mk2’s K2-X main engine lit up on time at T-3s under command of the AFCS, throttled at 10% power to check for good ignition. At T-0 after chamber pressures were confirmed to be nominal the 4 solid rocket boosters were ignited and their hold down bolts blown away to allow the rocket to begin its ascent with a combined force of 191kN to produce just over 1.6Gs acceleration. Immediately after launch all four of the rocket’s fins actuated to roll the rocket from 45° to 60° heading over about 6s before beginning to pitch over downrange. At the time pitch-over began the two horizontal fins nullified their ability to react to roll inputs so later in the flight at supersonic speeds control flutter would be kept to a minimum to reduce vibrations on the payload. By L+10s the SRBs had begun to taper off their thrust and the main engine throttle started to properly increase in order to maintain a TWR of 1.5.