This is my first KSP craft I’ve posted and is a homage to what maybe the most interesting what if space vehicle never to have flown, the X-20. (Requires Mechjeb otherwise Stock). After several years of doing add-ons for Orbiter, i thought id have some fun with KSP as well. Get it Here : https://www.dropbox.com/s/wcovzz4ytehd18z/X-20%20v1_1.craft?dl=0 The X-20 was America’s 0’th space shuttle. Originally conceived as a manned sub-orbital strike vehicle it morphed back and forth to being an space fighter, space bomber or space born spy platform in both orbital and sub-orbital configuration as well as a possible reusable winged space station resupply vessel. It also suffered from a lack of a decided launch platform with Titan 1, Titan 2, Titan C, Saturn 1 and Titan 3C being possible candidates at various times. The project was sadly killed by Robert MacNamara’s lack of for-sight in 1963 just a 8 months before before initial drop tests from a B-52 and the first manned flight in 66. The trainee USAF astronauts (including one Neil Armstrong) moved on to other things. Full orbital operations were planned for 1970. An alternative world would have seemed a small reusable manned US shuttle by the early 70s that could carry up to 5 crew to a space station in the follow on X-20X version. Here I’ve modelled the MK III X-20 orbital spy platform along with docking capability riding a Titan 3C. Of course so as to not raise the hackles of the government of the KSSR on the other continent, the ELINT devices have been cunningly disguised as research pods and what not. The Inline docking port allows KSSR satellites to be “inspected†up close if required. Stock parts only are used except for MechJeb controller. X-20 Flight OPS 1) Ascent Standard ascent to low orbits is possible. The transtage (stage 3) allows possible trans-munar missions but I’ve never tried it. Mechjeb can handle assents easily. Separate the second stage after a normal ascent and only remain with the trans-stage on orbit. 2) On-Orbit OPS The huge transstage allows for quick and very large orbital inclination changes. This allows for “surprise†overflights of KSSR installations. A full range of “scientific†instruments are available for your use as well as a massive ELINT antenna for capturing side scatter microwave conversations, cunningly disguised as a Communotron 88-88. On orbit manouvering options are many and excellent as would be expected for this craft. NOTE: In keeping with original X-20, there is no RTG or solar panels. An ample battery is provided for orbital ops but possibly a solar array needs to be added to the trans stage if longer duration missions are planned. Hence manage your power. 3) Landing For landing I utilise Mechjeb. I set the landing point a certain distance before the KSP runway and allow mechjeb to perform the first descent burn from orbit. I then switch the mechjeb autopilot off, discard the trans-stage and fly the descent from there. I set the mechjeb initial landing point as 1/4 to 1/3 of the way between the mountains west of the KSP and the KSP on a 0 degree orbit approach. That is closest to the mountains. This should place you over that selected landing spot at about 15000 to 12000m I fly using SAS on and kill RCS below 5000m. Control is usually pretty good below 5000m and the craft can handle fairly severe turns but tends to loose height rapidly if you have too high an AOA in a turn. Line up and stabilise the approach a long distance out if possible. Decrease or increase the vertical sink rate as required to reach the threshold. Remember its a glider so your nose will usually be around horizon level at best. Do not let the forward speed decay too much as you will start to loose lift and your vertical will then increase again rapidly, at a time when you are too low to recover. Touch down should be with as lower vertical as possible by -6.0ms should be safe on concrete or flat grass. You have to push the Gear button TWICE to lower the gear. Nose wheel has steering. Once you get good at it reentry landing can become routine and a fun challange and the craft can definately do it, so if you cant make the runway alive, dont blame me! 4) Abort / Pad abort The abort action group is wired to fire the 8 sepratrons at the rear of the X-20. This has enough force to haul the vehicle away from an out of control stack or even (JUST) do a pad abort. If you still have control over the stack when you abort, first push X to kill main engines if possible which will limit the chances of collision with the booster, thought the abort thrust should be good enough to clear it in most attitudes. PAD ABORT ACTIONS 1) PUSH ABORT 2) IMMEDIATELY pull 45 degrees over (PITCH UP) so the X20 is upside down and climbing away at 45 degrees 3) You have maybe 5 seconds of thrust. 4) When thrust has finished IMMEDIATELY roll the craft right side up 5) Follow the Prograde marker down as the airspeed drops with your nose ASAP, however do not go below -20 degrees pitch. If you have done things right the vehicle should be travelling at about 50+m/s in a slightly below horizon attitude 6) GEAR DOWN ASAP 7) Flair for landing slowly enough to not stall it with a high AOA but enough to get its Vertical sink down to acceptable landing levels. 8) Kiss the grass and roll to a stop 9) Jump out on the grass to be thanked by the KCIA for saving their "instruments" and KSAF for saving their vehicle. Note: the above makes a fun challenge in and for itself! Note: I believe USAF astronauts practiced aborts from the pad (simulated using a jet fighter (Skyray?) with a rocket at the rear) or possible early ascent where they landed/glided back to the Merrit island skid strip at Kennedy Space Centre with hair raising results not dissimilar to above! ASCENT ABORT ABORT during ascent is similar to the PAD abort when in the early stages of launch but naturally you have more time the higher the event occurs at. Down range however the prime concern is probably flight time to dry land if available. In reality it would have probably involved stabilising the craft over water at a reasonable height and ejecting. Also without orbital reentry velocity behind you and a straight in approach to the KSP, the X-20 will tend to dive until you can get some lift and vertical command authority probably sub 10000m and possibly even below 5000m. ORBIT ABORT In the case of simulated transtage failure, jettison the transstage and use the ABORT engines and rear RCS quadruple thrusters to deorbit as and where required. X-20 Mission IDEAS 1) Perform ELINT missions 2) Try a sub orbital long lob mission and land back at base or in the field (exceedingly challenging) 3) Simple fast transport to a space station 4) Satellite inspection 5) Quick and simple science missions with easy vehicle recovery. Future IDEAS for X-20 Variants. Nice if there was a MK-1 Cargo bay (simple sub-sat transport and release or capture) Nice if there was a MK-1 Crew compartment (maybe 2 or 3 more kerbals squeezed in back in the hull there with a docking ring added in the roof. What a .... way to go to Skylab in 1974. Hope you enjoy Rossco
