Mechjeb Landing Stops and Starts Warp Again
KSP Craft File: Kiwi Orbiter
If y'all play Kerbal Space Program, you inevitably get to a indicate where sending Kerbal crew members up and down to a space station becomes a mundane drain on your in-game greenbacks and your real-life fourth dimension and enthusiasm. It needs to be easy for the actor, and efficient for the game.
Design Trouble: We demand a space bus; a driver service. The standard "Go Up, Move Around, Come up Down" mission. Information technology needs to be very cheap, efficient, and undemanding of the actor.
Design SOLUTION: The Kiwi Orbiter
The Kiwi Orbiter is a partially-reusuable, low-cost/loftier-versatility space sheathing, designed to take iii Kerbals to a circular, equatorial Low Kerbin Orbit (LKO) of 245km, perform several rendezvous and docking maneuvers, and so re-enter safely for a landing at Kerbal Space Centre (KSC), with minimum of fuss, bother, hoo-haa, and flap-doodle to the actor.
The vehicle is congenital with precisely the right resource for the mission, meaning the player tin fly it past using mouse-clicks only and no planning, construction, or flight control inputs are required!*(MechJeb modern required for some operations).
It is an counterpart for the real-life Russian Soyuz TMA in terms of function, but takes more the physical form of a SpaceX Dragon in that it re-enters in one piece without a Service-Module Separation.
HERE is the download link, but delight read on for a total vehicle description and mission walk-through.
You MUST have MechJeb installed. Download MechJeb starting time here.
The ship is designed in game version i.3.0, and works in 1.3.one , ane.iv.0, 1.4.1, and 1.4.two.
FAQ: Why 245km orbit?Answer: 245km is my standard altitude for infinite stations. Information technology's high enough to enable the actor to use 1000x time-acceleration to cut down on existent-life waiting time for transfer windows. Additionally it is near the border of High Kerbin Orbit (HKO) which is handy if you need to catch extra high-altitude science, and information technology is a skilful jumping-off betoken for transfer burns to Mun, Minmus, or beyond. Your altitudinal needs may vary and will void warranty.
FAQ: Why use a sheathing-based space plan, when shuttles and SSTOs are the existent bargain when it comes to reusability? Reply: because spaceplanes are fickle and demand to be micro-managed and I actually can't stress strongly enough how much I caaaaaan't be fucked (CBF). With this sheathing program my real-life investment is as depression as it can mayhap be, while the in-game costs are comparable. For this reason, the Kiwi Orbiter is the backbone of my space program. Every crewed mission, whether to a space-station or to a big inter-planetary transport, begins and ends in one.
THE KIWI ORBITER
Primary function:
- LKO crew ascent and descent.
Secondary functions:
- ferry crew betwixt stations and vessels while on-orbit,
- emergency lifeboat carried on larger vessels,
- infinite tug for construction projects on-orbit,
- make New Zealand proud.
Fundamental FEATURES
LOW COST
Send Kerbals to space for just $7,000 per person *(once recovered from landing most KSC ).
FEW PARTS
A mere 20 parts *(orbiter but) ensures the next coiffure rotation doesn't turn your station into Kraken chow.
SINGLE-RESOURCE SIMPLICITY
Vacuum engines draw from the same large supply of monopropellant as the RCS, all merely eliminating the run a risk of running out of gas for RV and docking. Additionally, refueling is simple and no longer requires whatever irritating Lf+Ox balancing!
VERSATILITY
When fully fueled and in vacuum, orbiter has 1021m/s of delta-V (dV) (in 780 units of monopropellant). Afterwards subtracting for orbital insertion and de-orbit burns, actor is left with approximately 300m/s for on-orbit maneuvers – plenty for the average day of wildly inefficient RV and docking!
HANDS-OFF ASCENT
Vehicle flies itself to orbit with one click of the mouse *(using MechJeb mod).
NO MORE Droppings
Vessel is precisely fueled and weighted for Main Engine Cut-Off (MECO) and Stage Separation to occur simply before achieving positive Periapsis, leaving your planet 100% droppings-free and earning the Kiwi Orbiter the
Kessler Tick of Approval™
*(when using recommended ascent profile).
SLOW-Burn ASCENT
Low Thrust-to-Weight Ratio (TWR) and low strains during the atmospheric flight phase make any weighty, complicated and costly launch escape systems unnecessary, thus adding economic system. Booster Separation less resembles the fourth of July, and delicate tourists and VIPs are left conscious and with luncheon intact.
LIGHTWEIGHT
Due to its small size the Kiwi is very responsive under RCS, piece of cake to dock, and forgiving of mistakes. Its TWR is balanced for both orbital insertion and fine tuning an intercept. Mental attitude control is more than than acceptable nether reaction wheels alone, saving more RCS fuel for translating and thrusting.
Hands-OFF RE-ENTRY
Simply arm parachutes and relax! The entire orbiter re-enters in 1 piece, and tin can be recovered. No Service Module separation occurs, thus no risks of collisions, explosions, frame-rate problems, or creating debris. Flat solar panels need no retraction, and at that place are no external antennas.
Rubber RETURN
Estrus shield ablator is precisely pared down to the blank minimum (plus 400% prophylactic margin) in order to provide ameliorate dV and TWR throughout the mission. Triple parachute organization provides step-wise decceleration and soft-landing, without demand of player input or witting Kerbals.
COSTS
Crew: 3
Launch toll: $36,125.
Recovery: ~$xv,000 can usually be recovered, assuming re-entry and landing goes co-ordinate to plan.
Final cost: $21,000 for 3 Kerbals, or $7000 per Kerbal.
It's tough to detect anything cheaper than that!
Function LIST
Allow's talk about some of the design choices.
ORBITER:
- Shielded Docking Port. Low atmospheric speeds make launch escape tower unnecessary, and this port is more aesthetically attractive than an open up wound clamp-o-tron.
- Mk1-2 Command Pod (obviously). Provides 3 crew seats, reaction cycle stability, remote comm link. Likewise functions as reserve battery and fuel tank (with 48m/s dV); both resources are locked off by default.
- Parachutes. 2x radial main chutes, 1x radial drogue. Only one of the main chutes is necessary, the second is simply for aesthetic symmetry. Quite often to reduce role count farther I only replace one master chute with the drogue, just it doesn't look as good.
- Bombardment and Solar Panels. The largest possible battery is used. Why? Considering information technology makes the electricity supply virtually unlimited. Why practice we need almost-infinite power supply? Considering the solar panels used on the ship are the apartment single versions which sometimes don't generate much power (if, say, you timewarp without facing the lord's day). Okay and so, then why use apartment solar panels if they suck? Well, because foldable solar panels are a hurting in the neck and are hands broken. So information technology all stems from that. If the indicate of the ship is to exist 'hassle-gratis', and so I'm definitely going to remove solar panels that need to be folded away for protection when it comes time for docking or re-entry.
- Monopropellant Tank and 2x "Puff" Vacuum Engines. The largest 750-unit yellowish fuel tank is used, to fuel vacuum engines and RCS from the same source. The rationale is that while Puff monoprop engines have, granted, a terrible Specific Impulse (ISP) rating, in that location are other gains to be made from 1) visual clarity when refueling, to say nothing of being distinctive bright yellow and not boring gray, 2) no run a risk of your Lf+Ox tanks existence accidentally emptied or unbalanced equally sometimes happens when docked to a Lf+Ox-burning ship with crossfeed unhapp'ly enabled, and 3) the flexibility for the player to perform much, much more translation while on-orbit (i.eastward. docking, tugboating, more docking, MOAR DOCKING!). More specific dV readouts will follow below, but basically, what you pay for in ISP yous make up for in real-life freedom from worries, which ultimately is what this spacecraft is virtually. It must also be said that the Isp of the Puffs is non so unlike from that of Lf+Ox engines of a similar size.
- Mechanical Jeb Command Unit of measurement. The entire premise of the Kiwi Orbiter is to provide the player with hassle-gratuitous launch and a anticipated result every time. Information technology is designed for one mission only: the MechJeb autopilot ascent to 245km. Thus, the arts and crafts file will not be provided without the MJ unit attached, and yous will need to accept the modern installed in your Game Information folder for this vehicle to load in your game. Deal with it.
- Kerbal Engineer (KER) Flight Reckoner. This is optional, and the arts and crafts file is provided without it.
- Heatshield. The 2.5m version has had almost of the ablator removed, as it was not useful load. The remaining 160 units is approximately 110 units more than I have ever used on even the most aggressive re-entry profiles. NB: the Puff vacuum engines and RCS blocks will often go to temp gauges on re-entry, only never explode when properly pointing retrograde.
- –Not included: Antenna.– This is not necessary for a driver bus, non fifty-fifty for remote probe guidance. Add one if you really wish; I recommend the Communotron 16-S to continue the "no-encephalon-required" design approach.
FIRST Phase:
- 18 Sepatrons (Pointing Upwards). Staged with the separator. Okay, this may exist overkill, but I desire to exist absolutely certain that the first stage droppings does not accomplish orbit. Even if the Periapsis is merely +1m above the ground, the game will even so put it on runway and let it to continue orbiting. Non on my scout, sonny. Non on my sentinel.
- I Orange Tank with "Skipper" Engine. Let's talk nigh the Skipper. The Skipper rocket motor is under-powered and useless, correct? Well, combined with two boosters, information technology actually performs perfectly for what this mission requires. As noted to a higher place, the rising is very docile, and majority of the fuel is burned merely after a satisfactory ISP rating has been reached college in the temper. Thus, the employ of the Skipper is the number one toll saver in this vehicle. In the configuration I have provided, it has a huge border over the more expensive Twin Boar or Mainsail rocket motors you otherwise might want to use.
- 4 Stabiliser Fins. Keeps everything flying in a nice, vaguely pro-grade orientation.
- 2x "Thumper" Solid Rocket Boosters (SRBs). The two inexpensive and disposable boosters provide a "just right" amount of thrust in the starting time phase of the flight. Using them downward low in the temper is what allows for the cost savings of the Skipper at higher altitudes, every bit noted above. NB: They are Autostrutted to Orange tank without demand for EAS Struts, and still divide just fine, thank you.
MISSION WALKTHROUGH
Now you know all about how the vehicle is built, it's time for a walkthrough of the whole mission, with all the technical details included. There are viii steps in the rising phase.
- Pre-launch.
- Launch.
- Booster Separation.
- Max Q.
- MECO, Phase Sep, and Vacuum Engines Outset (VES).
- Vacuum Engines Cut Off (VECO).
- VES-2 Circularisation Burn.
- VECO-2 Autopilot Disengage.
And after, another 8 steps in the descent. But let'due south deal with the ascent kickoff.
ASCENT:
ane. PRELAUNCH.
- NOTE: WHILE MECHJEB ENSURES EACH MISSION IS Virtually IDENTICAL, There ARE QUANTUM FLUCTUATIONS THAT CANNOT Be ACCOUNTED FOR AND WILL CAUSE YOUR DELTA-V CALCULATIONS TO VARY.
- Open MechJeb.
- Open up 'Ascent Guidance'.
- Enter '245' in the 'Orbit Altitude' box.
- Cheque all other MJ settings lucifer those shown in the screenshot (they are all the defaults and then y'all shouldn't have to change anything at all).
- Verify coiffure and staging has not been garbled.
- Press the 'Z' central to become total throttle.
- RCS disabled.
ii. LAUNCH.
- Press 'Spacebar' to activate start phase engines and docking clamps.
- As quickly as possible, click MJ 'Engage autopilot' button.
- Now that the vessel is on its manner upward, you may press '>' fundamental to utilize time acceleration as desired.
3. BOOSTER SEPARATION AT MET00:42.
4. MAX-Q AT UNKNOWN TIME – Aerodynamic forces are then low that it doesn't matter.
v. MECO, Stage-SEP, AND VES-i AT 02:35
- Sepatrons and Separator will automatically activate through staging. The get-go stage falls dorsum to Kerbin.
- The orbiter will tumble a trivial, and re-orient itself pro-grade.
- The two Puff vacuum engines will appoint, to finish raising apoapsis to 245km.
6. VECO-1
- Vacuum engines volition throttle downwardly and fine-tune apoapsis earlier cut off.
- MechJeb will declension to border of atmosphere, create a circularisation node of ~250m/south, re-orient the vessel, and appoint time-warp.
7. VES-two CIRCULARISATION Fire AT ~12:05
- Vacuum engines throttle up to raise periapsis.
- Advanced users may click MJ 'Disengage autopilot' at Pe=140km to combine this circularisation burn with a Hohmann rendezvous maneuver. I do this almost every unmarried time.
8. VECO-2 AT 13:04.
- Engines throttle downward, autopilot disengages.
- Role player may now presume command of the vessel.
- Game time elapsed is 13:04, but existent-life fourth dimension elapsed is only 02:27.
- Delta-Five: I take run over 100 ascents and kept information (some pictured below), and found that most times there volition be ~770m/s remaining. However some physical fourth dimension acceleration bug alter the MJ ascent profile and leave merely ~690m/s remaining (you can tell this situation is occurring if your boosters explode on separation – no known workaround exists sorry). Some other unexplainable quirk in the cosmos will cause the ascent to go more efficiently and leave you lot with ~810m/s of delta-V. No guarantees!
DESCENT PHASE:
1. CHECK SETTINGS
- Cheque you take enough fuel! You need approximately 300m/s of dV to consummate the recommended MJ-car landing at KSC. Otherwise the standard "eyeball your burn down and then your periapsis touches the eastern peninsula" program may be used.
- Check your orbit is clear of objects and ready for a burn.
- Check you have control of the ship i.e. either Pilot on board or Remote control link, with reaction wheels enabled and plenty of electrical charge. Ablator, obviously. All the usual stuff.
- Check fuel tank menstruation is open.
- Toggle the engines to ON (action group ane by default).
- OPEN MECHJEB LANDING GUIDANCE PROGRAM. Set your landing target for "KSC Pad" and click "gear up" twice. If successful then target coordinates will announced. Ensure "show landing predictions" is enabled.
2. DE-ORBIT BURN
- Switch to map view
- Click "land at target"
- The ship will at present fourth dimension warp up to the burn point, turn and indicate retrograde, and engage engines..
3. DISENGAGE AUTOPILOT!!!
- This is crucial. Yous MUST click "abort autoland" when the estimated distance reads 21km from KSC.
- If you need to adjust it (I normally do) you lot can do some manual burns either prograde or retrograde, using RCS or main engines as you meet fit. The but thing that matters is that your landing prediction is reading an overshoot of 21km, and that you reach this equally quickly as possible after the autopilot disengages.
iv. DEPLOY CHUTES, ORIENT RETROGRADE
- You are now gratuitous-falling towards the Kerbal Space Center. The 21km overshoot is precisely designed to reduce to goose egg subsequently entering atmosphere.
- Deploy your chutes. They are in the staging by default, merely you tin can also exercise this manually by right-clicking them.
- Use MechJeb SmartASS (or a pilot if you are super, super sure they won't lose consciousness on re-entry) to HOLD RETROGRADE.
- Goes without proverb that you need electric charge to run the reaction wheels to hold retrograde. If you are out of charge (how the hell did y'all manage that?) then yous should use remaining RCS fuel.
5. RE-ENTRY HEATING
- Vessel will re-enter the temper and hopefully concord retrograde well enough that zip will explode and your aiming is not spoiled by aerodynamic elevator.
- The engines and RCS blocks will become to temp guages.
- Do not panic.
- Practise not touch the controls.
- Pray to deity/deities.
- You lot may fourth dimension accelerate, but this sometimes causes overheating. Use discretion.
6. PARACHUTES OPEN
- If you lot've done it right, information technology should await like this!
- Don't touch anything.
- If y'all really screwed up your approach, this is your concluding adventure to utilize your engines to state closer to KSC.
7. LANDING
- Easy every bit pie! Bob'due south your uncle, and Val'south your aunt.
- Sometimes things will explode. Sometimes the heatshield. Sometimes the engines. Sometimes both or nothing. This is the run a risk you running by landing on terrain – if it really bothers you I suggest changing your approach from "21km" overshoot to "23km" overshoot to ensure you country close to the KSC but in the water.
- If you'd like to exist certain of zero exploding, you could lighten your bear upon by burning your engines at the last moment to expend fuel mass and reduce airspeed. But honestly, meh.
- It don't go much prettier than that!
8. RECOVERY
- Click the greenish "Recover Vessel" button similar normal and reap rewards!
- Thank you for flying the Kiwi Orbiter. We hope to encounter you again.
Source: https://andrewsnewblog.wordpress.com/2017/09/18/kiwiorbiter/
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