KerbalX

Description

A stock rocket called Kerbal X2. Built with 114 of the finest parts, its root part is mk1-3pod.

The Kerbal X2, like the Kerbal X1, modifies the stock Kerbal X by replacing the X’s core Mainsail with twin Vectors and its booster Swivels with Reliants.

Unlike the X1, however:

• The X2’s third (final) pair of boosters are identical to the first two pairs (standard-length and Reliant-powered), in contrast to the X1’s stretched, Dart-powered, sepratron-aided-separation third set of boosters.
• The Vectors’ pitch and yaw gimballing can now be toggled on and off separately from their roll gimballing (as the rocket becomes prone to overcontrol - and the resultant control oscillations - much earlier in roll than in pitch and yaw, making it desirable to control roll gimballing separately from pitch/yaw gimballing); pitch/yaw gimballing toggles on and off with 3, as was the case for all control axes with the X1, while roll gimballing now toggles on and off with 4.
• Unlike the X and X1, which were designed as standalone spacecraft best suited for landing kerbals on other celestial bodies (and, optionally, returning them to orbit, and, even, possibly, to Kerbin), the X2 is designed to serve as the core of an orbital space station, remaining in space indefinitely if possible. As a result of the change to a space-station design:
  • The capsule’s landing legs, parachutes, and heatshield are now superfluous, so these parts have all been removed to free up mass.
  • The capsule no longer being designed for reentry into Kerbin’s atmosphere, there is now no need to separate it from the vehicle’s upper stage, so the stack separator that lies between the two on the X and X1 has been removed, making the upper stage integral to the craft.
  • More and larger docking ports have been added to the sides of the X2 (greatly improving on the X1’s complement of a mere two Clamp-O-Tron Jr. ports and the X’s complete lack of any docking equipment), and a shielded docking port (shield closed to reduce drag during ascent, and opened once in orbit) takes the place of the X-and-X1’s main parachute on the nose of the vehicle.
  • More and larger solar panels are used on the X2 for improved long-term power supply, with a higher-capacity battery for greater electrical storage capacity.
  • A large reaction-wheel module and extensive RCS system (fed by a substantial-capacity monopropellant tank) have been added for improved flight control and rendezvous capability; the additional reaction-wheel authority provided by the dedicated wheel module (along with the X2’s higher battery capacity) allows the X1’s large-size Steadler RGU (chosen over the smaller model for its greater electrical storage capacity and reaction-wheel authority) to be replaced with the smaller, lighter, cheaper model of RGU.
• The X2’s upper stage has been stretched considerably, using tankage that was part of the lower core stage in the X and X1; this both makes room for more docking ports and ensures that the lower core stage exhausts its fuel and oxidiser, and is dropped, before the vehicle reaches orbit, greatly reducing the amount of structural mass that has to be dragged around.
• As the X2’s lower core stage (being significantly shorter than that of the X and X1 and lifting a larger, longer vehicle) no longer reaches orbit, it makes sense to design it for recovery, in contrast to the expendable core of the earlier vehicles (which would, except in the event of a launch abort or for certain flight profiles not making use of a parking orbit in LKO, be jettisoned onto a stable orbit and not reenter Kerbin’s atmosphere). Thus, airbrakes and parachutes have been added to the lower core stage (the former to slow the stage during reentry and hypersonic/supersonic descent, and the latter for the final soft landing).
  • To allow the airbrakes to work without having to deploy them before staging or include a probe-core reentry controller in the lower core, airbrake deployment, along with parachute deployment and lower-core separation, has been tied to the abort action group. The lower core, when exhausted, should be staged away by pressing the abort key (defaults to backspace), or by clicking the abort button that slides out to the left of the altimeter, not by using the normal staging hotkey (defaults to spacebar); otherwise, the airbrakes will fail to deploy (although the parachutes will still work), and the less-draggy lower core will maintain a higher speed lower in the atmosphere (worsening aerodynamic heating and potentially causing parts of the core - especially the expensive Vectors, which, due to their great weight, tend to lead the stage through the atmosphere - to blow up), potentially enough so that it never slows to a safe parachute-deployment speed before impact.
  • As the lower core no longer reaches orbit, the mass penalty from carrying the stabilisation fins along with it is decreased, allowing them to be moved from the boosters back to the core without too much negative effect.

Built in the VAB in KSP version 1.10.0.

Details

• Type: VAB
• Class: station
• Part Count: 114
• Pure Stock
• KSP: 1.10.0