Temstar

The KSP wiki has a much better picture of Kerbin-Duna atmosphere comparison: 20% pressure at sea level relative to Kerbin is pretty forgiving when it comes to parachute landing. Mars for example have only 0.6% of Earth's atmosphere pressure at its "sea level". Wiki also has a Kerbin-Eve graph

Jebus, what kind of mission need that kind of fuel requirement? As for RCS transfer, no you just need the fuel transfer but, you don't need the computer. As a matter of fact from what I can see the placement of the fuel transfer thing on your propellant depot doesn't actually matter, what type of fuel gets transferred depends on the type of the target tank not the source tank. How do you fly a 6400L tanker and get it to dock? I find that big spaceship is pretty unwieldy when it comes to be the active partner in docking so I tend to use small tankers. For example, here's one of my light tanker refuelling my Duna/Ike mission stack.

I personally think Squad is not quite taking docking seriously enough. Docking is such a vital part of any space program that we might still be trying to land on the moon today had we stuck to direct ascent. As soon as NASA could put a man into orbit they started planning for Project Gemini to get EVA and docking working because these two things are essential to landing on the moon. Seen as we've just got EVA working in KSP the logical step next should be docking.

Look carefully at the fuel line below, notice how one pair of parallel stage boosters feeds another pair, which then feeds a third pair which then feeds the center sustainer motor? This allows each pair to be dropped as soon as the fuel is consumed while keeping the inside of the asparagus fully fuelled until the staging event. This is an extremely efficient way of staging and can get pretty complicated when you have many layers, hence the point of this thread.

Awww nuts, adjusted angle doesn't work with combined spacecraft created by docking mods:

There are two docking mods: http://kerbalspaceprogram.com/forum/showthread.php/20503-Plugin-Part-0-16-Erkle-Mods-Warp-Capable-Docking-Clamp-v0-4-released/ http://kerbalspaceprogram.com/forum/showthread.php/20604-Plugin-Parts-0-16-Orbital-Rendezvous-and-Docking-Assistant/ They each have their own strengths and weaknesses. ORDA has a fantastic docking computer which can actually keep the target ship stable while you approach and has all sorts of handy functions. It can also transfer both fuel and RCS but the docking itself is fickle and pretty fragile. Erkle has very strong docking and one click fuel transfer but no other functionality. I use both on my ships. Here's a tanker rocket coming to dock with the Duna stack to refuel both ships.

No but you can only be "Killed in action" if you die due to hostile attacks. Non-hostile events cannot cause KIA by definition.

That's not that good of a reason. We know how to clean up radioactive contamination. It's not really any worse than hypergolic rocket fuel which are highly corrosive, highly toxic, produces carcinogenic exhaust and was used to fuel Titan rockets that flew the Gemini spacecrafts.

Eve is like a bigger, purple-er Venus with a much thinner atmosphere. If you think Eve's 5 bar at sea level atmosphere is thick check out Venus's atmosphere, it's 93 bar at the surface.

Kiwi-TNT In January of 1965, the U.S. Rover program purposely placed a Kiwi Reactor (KIWI-TNT) on fast excursion to simulate a worst-case scenario of a fall from altitude into the ocean such as might occur in a booster failure after launch. The rocket was positioned on a railroad car in the Jackass Flats area of the Nevada Test Site, with the reactor specially modified so as to go critical. The radiation released would have caused fatalities out to 600 feet and injuries out to 2000 feet. With current solid-core nuclear thermal rocket designs, it's possible that potentially radioactive fuel elements would be dispersed intact over a much smaller area. The overall hazard from the elements would be confined to near the launch site and would be much lower than the many open-air nuclear weapons tests of the 1950s.

Having played around a lot with the atomic rocket engines I've come to the conclusion that they are king of spacecraft propulsion for all but the smallest spacecraft. So the question is: how come we don't use them in our rockets like the Kerbals? Our own NERVA rockets could manage 800s-1000s Isp and could reach a TWR of 7, much better than LV-N which is below 3. Both the US and Soviet Union have launched nuclear reactor powered satellite into LEO before and a NERVA reactor cores are very tough and have been successfully destructively tested to cause minimal containment in case of failure. So how come Kerbals are ahead of us?

Killed in action Although it's kind of wierd since it's a military classification, I had figure KSP as a civilisan space program

Interplanetary Vessel Thunderchild docked with Heavy Planetary Lander Tiger Moth, waiting on orbit for Duna transfer window. If the docking hold this will be an Apollo style 3 man Duna + 3 man Ike landing and return mission

I get the feeling Jeb is like a Deke Slayton of Kerbal space program - Head of the kerbonaut office and thus the boss of all the other kerbonauts and the person who picks who will fly which misson. Which would put him in a position to pick himself for dangerous/high profile missions. But the parts description also says he runs a rocket parts company that specialises in selling rocket engines built from bits found lying on the side of the road. Funnily enough the Mercury Seven astronauts where each assigned a specialty area of the space program they were ment to keep track of and represent the astronauts office for, and sure enough Deke happens to be responsible for booster development. I wonder how Jeb finds the time to handle these two jobs at once. Is there anything else we know about the man and what his involvements are in the space program?

Drag is mostly to do with the speed you fly through the atmosphere rather than time. Take an extreme example: if there were magical floating steps in the sky and you are climbing up at a walking pace then all of the energy you expand in your legs would be used to fight against gravity and almost none of it would be because of drag. Or another way to look at it: On a celestrial body with no atmosphere, pure rockets always beat spaceplanes because wings are deadweight On a 1G / 1 atm body like Kerbin, rockets and hybrid rocket/spaceplane have similiar performance as shows in my experiment. Wings give you lift which allows you to left off with more weight but they also impose weight penalty on your ship. It follows that on a 1.7G but 5 atm body like Eve, spaceplanes would have a significant advantage over pure rockets in the lower atmosphere. Hybrid rocket/spaceplane should have a significant advantage over pure rocket power.

But the point is, if we use wings to generate lift as we take off from Eve's surface we should be able to get a spacecraft with very low TWR off the ground. If 0.3 TWR is possible on Kerbin/Earth than under 1.7G and 5 atmosphere pressure even lower TWR should be flyable. This very low TWR spacecraft would burn fuel at a very low rate compared to a 2 TWR Eve lander. The catch is this rocket plane would spend much longer to achieve orbit which results in greater gravity drag. So the equation is: Pure rocket Eve lander low gravity drag since it ascends vertically and quickly reaches orbit high air drag because it attempts to quickly punch through that very thick lower atmosphere Rocket plane Eve lander high gravity drag since it ascends in depressed trajectory and takes much longer to reach orbit low air drag because it climbs out of the lower atmosphere slowly The question is is the trade off worth it, my gut feeling says yes, seen as Eve's gravity is 70% greater but its sea level atmosphere pressure is 400% greater. To do a quick test I built two rockets attempting to put a small spacecraft into Kerbin orbit, one conventional rocket and one a horizontal take off rocket plane. I tried to make them both as efficient as possible to loft the spacecraft up into 75km orbit and compared the two rocket's weight at take off: As expected, the pure rocket manages to launch the spacecraft with lower take off weight. But surprisingly the results were pretty close. Given that this test is conducted under 1G and 1 atmosphere pressure I'm seeing this as evidence to support that a smaller winged rocket on Eve would be able to loft the same payload as a larger conventional rocket. Seen as weight is a critical issue in lander design picking the right choice would make an enormous difference in size at take off from KSC. To fly Pathfinder X-2, do the follow: 1. Throttle to full, stage to light the engine 2. glide on the runway until you reach about 90m/s, pull back on the pitch gently and nose up. Once you start to climb turn on ASAS and stage to jettison the landing gears 3. Nose up to 65 degree (do it while ASAS is on to be safe) and hold it there, let the rocket plane climb 4. Once the fuel in the side stages are gone (should be somewhere about 14,000m) stage to jettison all the spaceplane parts and convert to pure rocket mode 5. Burn to orbit as you would a normal rocket

I did some research: Take a Boeing 747-400, at maximum take off weight it's 396,890 kg. It's four Pratt & Whitney PW4062 turbofan generates 282 kN of thrust each for a total of 1182kN. TWR for whole aircraft = 1182 / (396890 * 9.807) = 0.000307 Yet despite such a poor thrust to weight ratio compaired to our rockets (remember, recommended TWR for rockets at take off is around 2, and decreases as you climb) the 747 can take off no problem. How? It generates a lot of lift from those big wings. A 747 at take off is flying in a 1G environment at 1 atmosphere pressure. Our Eve spaceplace will be taking off in 1.7G at 5 atmosphere pressure. In that thick of an atmosphere even tiny wings of a winged rocket will be generating tremendous amount of lift. Therefore a rocket with small wings in the shape of an enlarged X-15 should be able to take off and slowly climb in the thick Eve atmosphere with very low level of rocket thrust. As the atmosphere thins out the thrust required to keep it aloft will be increasing as lift decreases, however this is compensated by the fact that the rocket plane is also becoming lighter by burning fuel and jettisoning empty tanks. As a matter of fact if we make it so we keep staging empty tanks we may be able to keep the same set of aerospike engine from lift off all the way to orbit.

The wiki says Which sounds to me like as if the person wrote that DID manage to see useful thrust from engines at higher altitude. Can anyone confirm if that's true or not?

What if we use a 3 stage pure rocket powered spaceplane for Eve lander? It will deorbit and glide to a "water" landing in the mercury ocean. The Kerbonauts can get out and do some SCIENCE on top of the wings then get back in. The the lander will take off on a small number of aerospike rockets (TWR less than 1 when taking the weight of the whole craft) and fly in depressed trajectory using lift from the wings just like a Kerbin plane. Climb to say 30,000m, stage and blow off stage 1 and become a smaller spaceplane with the canard of the previous stage as the main wing of this stage, climb higher and stage again and then accelerate to orbit on pure rocket powered stage 3?

I'm planning an Apollo style Eve landing mission using all stock parts + the two docking mods. The interplanetary carrier is done (9,600L capacity, 7 nuke engines) and the test lander for a Duna + Ike landing is nearly ready too. If all goes well the Duna test mission will be carried out sometime late this week and results will be posted next week. Assuming docking and everything else work I should be able to delivery a "big" lander to and from Eve. The only Eve lander I've seen though is one LV-T45 with 12 asparagus staging aerospikes with a total fuel load of 20,800L at full capacity. A lander of this size is probably too unwieldy even for the carrier I've got. A return mission may still be possible but will probably require tanker rocket(s) to arrive from Kerbin to refuel the lander and mothership waiting in LEO before a landing and return trip could be attempted.

I believe you need to be able to put out around 12,000m/s delta-v after lift off if you launch from sea level.

I really dig the Soviet N-1 rocket's unique engine arrangement (think about it, it's actually a gimballed toroidal aerospike engine made up of 30 smaller engines). Thanks to the efficiency of asparagus staging such big engine clusters are a common sight in KSP. So let's share your most impressive looking asparagus engine cluster. Here's my: Stage 1: 12 BACC big SRBs tipped with liquid fuel tanks to get this bad boy off the pad, the liquid fuel feeds the inner engines Stage 2: 4 aerospike with seven 400L tank each on top Stage 3: 2 aerospike with three 400L and one 200L each on top, setup so that the tanks feed the center spacecraft while the engine feed off the spacecraft tanks. This way I can drain them first but then have the two aerospikes keep burning out of the spacecraft's own fuel. The aerospike is connected to the tanks with a decoupler to prevent tanks from feeding downwards Stage 4: spacecraft's own 7 nuclear rocket cluster, for final 200m/s burn into orbit. The spacecraft is a 9600L capacity interplanetary mothership designed to carry multiple landers. It will be refuelled on orbit to top up the tanks before leaving.

Yeah they fixed all the fuel and throttle bugs in 0.17 and nerfed performance of parts. I had to increase fuel load of my SSTO to make up the difference, end result being the plane's performance became more sluggish at take off. Craft file is attached. Mark 1 is all stock, Mark 2 supports docking and on orbit refuelling using Erkle and ORDA docking mods

So recently I've been playing around with both Erkle and ORDA docking mods with the goal of developing techniques for interplanetary landing and return trips, particularly for the harder targets like Eve and Laythe. The test Mun mission turned out to be a great success. Here's a run through: At the start of the mission, an Olympus class orbital propellant depot is already waiting on orbit with one crewmen. (prototype shown above with two spacecraft docked) The depot holds a large quantity of both regular and RCS fuel and will function as an orbital base in the future for Mun missions. The other ship involved in the mission is the lander, here it's taking off with the two remaining crew to join with the depot. At LKO, the two ships join up. For this occasion I picked the aft docking port of the Olympus to dock the lander, you will see in a moment why. Time for trans-munar injection. While Olympus has plenty of fuel and thrust for TMI it's radial engines have awful Isp. So instead I elected to use the lander's highly efficient nuclear thermals rockets for the TMI burn to push the entire combined spacecraft into munar orbit. There's a trick to this: the two spacecraft's navigation must be in agreement with each other, otherwise they will fight each other for steering and cause the combination to spin out of control.. For this burn I set both spacecraft to R&D > ATT> HOLD. This makes both ships try to keep their heading at the moment the HOLD command was switched on. Although efficient, the low thrust of the nuclear thermals rockets ment an unusually long burn. During the burn I did some fuel transfer test - turns out the fuel transfer rate between Erkle docking claw is quite high. Here we can see it's way higher than the burn rate of three nuclear rockets. Also interesting is the fact that fuel feed will continue after the receiving ship's tanks are filled if it's burning fuel - the transfer will just drop to equal to the burn rate. 8 hours later, the two ships arrive above Mun. The crew turn the combined spacecraft around and fire the nuclear thermals rockets again to slow down and settle down into a munar orbit. While orbiting the moon, the lander crew fully fuel the lander and wait for the go for PDI. Word from KSC is a go and Apokee Lander undocks from Olympus and begins powered descent initiate. Apokee Lander successfully lands on the Mun! Commander Tombree climbs down first with lander pilot Gilfurt right behind him. Tombree does his Peter Pan thing with his MMU EVA is over and the crew gets back inside and lifts off and head back meet up with Olympus Having linked back up again. Gilfurt gets out to work the RCS fuel lines to refuel the lander. Much like the ISS and its docked Soyuz the Apokee Lander function as a lifeboat for Olympus. Should it be necessary the crew can evacuate from the depot using the lander and escape to either a different orbit or Munar surface to wait for rescue. Thus it's a safety requirement that the lander is loaded with full fuel when docked. Neither Olympus or Apokee Lander are intended for re-entry for this mission (though Olympus have the capability). Instead they are intended as a permanent Mun presence. To get our heroes back a new crew is launched from KSC in an Apokee II cis-munar spacecraft and heads for the Mun The three ships join together above the Mun while the two crews exchange greetings and conduct handover. Apokee II arrives with more fuel and RCS fuel than required to get back so the additional fuel are pumped into Olympus's hold. With the crew exchange complete the original crew undocks Apokee II from Olympus and fires its engine for TKI to take them back home. Apokee II successfully re-enters atmosphere. Since the nose of the spacecraft is taken up by the docking port Apokee II does not have an XL parachute. Instead it mounts three regular Mk16 parachutes. Splash down and a heroes welcome for the crew! You can find the craft files and link to the mods here: http://kerbalspaceprogram.com/forum/showthread.php/22560-0-17-Erkle-ORDA-Orbital-Propellant-Depot-Olympus

So in a testing for docking and planned interplanetary travel, I decided to undertake an Apollo style mission using an Olympus class and a nuclear powered reusable Apokee lander: At the start of the mission, an Olympus class is already waiting on orbit with one crewmen. The other ship involved in the mission is the lander, here it's taking off with the two remaining crew to join with the depot. At LKO, the two ships join up. For this occasion I picked the aft docking port of the Olympus to dock the lander, you will see in a moment why. Time for trans-munar injection. While Olympus has plenty of fuel and thrust for TMI it's radial engines have awful Isp. So instead I elected to use the lander's highly efficient nuclear thermals rockets for the TMI burn to push the entire combined spacecraft into munar orbit. There's a trick to this: the two spacecraft's navigation must be in agreement with each other, otherwise they will fight each other for steering and cause the combination to spin out of control.. For this burn I set both spacecraft to R&D > ATT> HOLD. This makes both ships try to keep their heading at the moment the HOLD command was switched on. Although efficient, the low thrust of the nuclear thermals rockets ment an unusually long burn. During the burn I did some fuel transfer test - turns out the fuel transfer rate between Erkle docking claw is quite high. Here we can see it's way higher than the burn rate of three nuclear rockets. Also interesting is the fact that fuel feed will continue after the receiving ship's tanks are filled if it's burning fuel - the transfer will just drop to equal to the burn rate. 8 hours later, the two ships arrive above Mun. The crew turn the combined spacecraft around and fire the nuclear thermals rockets again to slow down and settle down into a munar orbit. While orbiting the moon, the lander crew fully fuel the lander and wait for the go for PDI. Word from KSC is a go and Apokee Lander undocks from Olympus and begins powered descent initiate. Apokee Lander successfully lands on the Mun! Commander Tombree climbs down first with lander pilot Gilfurt right behind him. Tombree does his Peter Pan thing with his MMU EVA is over and the crew gets back inside and lifts off and head back meet up with Olympus Having linked back up again. Gilfurt gets out to work the RCS fuel lines to refuel the lander. Much like the ISS and its docked Soyuz the Apokee Lander function as a lifeboat for Olympus. Should it be necessary the crew can evacuate from the depot using the lander and escape to either a different orbit or Munar surface to wait for rescue. Thus it's a safety requirement that the lander is loaded with full fuel when docked. Neither Olympus or Apokee Lander are intended for re-entry for this mission (though Olympus have the capability). Instead they are intended as a permanent Mun presence. To get our heroes back a new crew is launched from KSC in an Apokee II cis-munar spacecraft and heads for the Mun The three ships join together above the Mun while the two crews exchange greetings and conduct handover. Apokee II arrives with more fuel and RCS fuel than required to get back so the additional fuel are pumped into Olympus's hold. With the crew exchange complete the original crew undocks Apokee II from Olympus and fires its engine for TKI to take them back home. Apokee II successfully re-enters atmosphere. Since the nose of the spacecraft is taken up by the docking port Apokee II does not have an XL parachute. Instead it mounts three regular Mk16 parachutes. Splash down and a heroes welcome for the crew! Apokee Lander craft file attached for those interested.