Torquemadus

I refer to the SRB-KD25k simply as the SRB. When I mention the SRB in threads, this is the part I'm referring to. I'd have pet names for the larger SRBs used for heavy lifting, but there aren't any large SRBs in the stock game.

I've finally got to the point in my 0.90 hardcore custom difficulty save where I have enough tech to use the lightest version of my Kerbooster. Here are some pics of launch vehicles used in my current hardcore save:- This is Kercury 8, which is a good example of my BACC booster based early game launchers. This is Kercury 11. I used SRBs to send a number of these ships to spam contracts from both of Kerbin's moons. This is the Kerbooster Light, which uses SRBs to perform low cost satellite launches. I can launch larger versions of the Kerbooster, but I have to spam large numbers of SRBs as a first stage. The current SRB-KD25k is too weak for heavy lifting. It can only be used to lift large payloads if clustered in large numbers. A larger SRB is needed for use with the 2.5m and 3.75m parts.

I'm playing a 0.90 stock save on hardcore custom difficulty. As you can imagine, things can get a bit grindy if I don't do a good job of planning missions and minimising launch costs. In previous patches, I used my Kerbooster fly-back booster family to keep launch costs under control. As my 0.90 save begins to make progress, I'm ready to start introducing Kerboosters in 0.90. My crewed missions to Kerbin's moons are still using the expendable Zedstone booster, which can be used to throw crewed spacecraft to Kerbin's moons at a good price. Once there, they can perform landings and/or spam orbital survey contracts, earning back vastly greater amounts than they cost to launch. Earning money from satellites is more difficult, since they usually complete only one contract before returning to Kerbin for recovery. There are some other contracts they could perform, but I have crewed survey ships stationed at Kerbin's moons that can deal with those. The satellites need a cheap launch vehicle to keep their contracts economical. The Kerbooster is a low cost two stage to orbit (TSTO) launch vehicle. It consists of an expendable solid rocket stage, and a liquid fuelled fly-back stage. I've built much larger versions in previous patches, but this version is designed to work within the limits of my current hardcore difficulty save and the limited building upgrades I've been able to afford. Pictured below is the Kerbooster in it's lightest configuration. The staging strategy is similar to the Zedstone, but performance is sacrificed in favour of re-useability. It uses four SRBs as a first stage and uses a similar second stage to the Zedstone. The solids provide all of the first stage thrust. I pause briefly before igniting the second stage to give the solids time to get clear after separating. An important feature of the Kerbooster Light is that the satellite is still counted as having undergone an uncrewed launch. While I'm at it, I recover the cost of the launch clamps, which are still present on the launch pad as debris. There's a myth going around in KSP that funds can only be recovered from debris if it has a probe core attached. Actually, it can be recovered, but you don't see the dialogue telling you how much money you got back. If in doubt, check how much funds you had before and after recovering. Depending on the size of the payload, my Kerboosters often have spare fuel when they reach orbit, so I often use part of their remaining fuel to perform some, or all, of the departure burn. In this case, I stopped the burn part way because I wanted to preserve a good reserve of fuel for recovery. I don't actually need all that much fuel to get back to Kerbin, but my re-entries are often off target, so I like to keep a reserve of fuel in case I need to compensate. I usually do a few aerobraking passes first. These make it easier to perform an accurate re-entry, so that I can hopefully bring my fly-back booster down within gliding distance of the KSC. It's always difficult to get an accurate re-entry without mods. I usually count myself to have been successful if I emerge from re-entry heating somewhere over the KSC. After all, I can easily circle around to loose height. Next, I need to turn around and line up with the runway. I used to position the rear wheels under the wings, but since 0.90, I've had to move the wheels to the fuselage for stability. It sucks to make it all the way back to the runway, only to end up flipped upside down. I could get better performance if I used a probe core instead of a pilot. However, the fly-back stage is designed to glide long distances if my re-entry is inaccurate (which it often is). If I do a long glide after a night re-entry, I often run out of electricity for my reaction wheels. My fly-back stage can still land without reaction wheels, but only because the pilot doesn't run on electricity!

This is the smallest version of my Kerbooster stack shuttle. I use it for satellite contracts on my hardcore custom difficulty save. It's part of my family of fly-back boosters that I use in place of shuttles. It's two stage to orbit, but the only parts that are expended are "trash bins full of boom" SRBs, which are dirt cheap, and are worth next to nothing when empty anyway.

I landed too far from my four EVA sites to walk. A test jetpack flight showed that EVA fuel was going to be marginal, especially since I had only an approximate idea of there the sites were. Therefore, I decided to move my ship closer. I dropped it in at the Gamma site and visited the others via the jetpack. - - - Updated - - - There's no good reason why you couldn't have a compass. A compass should be standard kit for exploring any geologically inactive body that doesn't have a magnetic field!

The visual survey contracts require you to be either above or below a specific altitude. I often spam survey contracts from polar orbit, since I can visit many sites with only a tiny amount of fuel expended to adjust my orbit to get the right altitude.

His actual name is Austin Kerman. Danger's his middle name!

It's worth pointing out that the ISP of a rocket engine depends on it's exhaust velocity, which depends on the molecular weight and temperature of the exhaust gas. Ideally, you want the gas coming out of the exhaust to be molecules of a very light gas such as hydrogen, heated to the highest possible temperature without melting the engine. Remember that the goal is to give the rocket as much kinetic energy as possible for a given mass of fuel. Nuclear and solar thermal rockets can use hydrogen because they don't have to react it with anything else to get the energy needed to heat the propellant. The absolute best performance available from chemical rockets is achieved by reacting the hydrogen with oxygen to produce water. An alternative way to fuel a thermal rocket is to use water. This will produce the same ISP as a chemical rocket, but has the advantage that you can refuel anywhere you can find water. If you want to refuel with hydrogen instead, you'll need to electrolyse some water to get the hydrogen out, which requires a lot of electrical power. The performance of the LV-N in KSP suggests that it uses hydrogen, since it has a much higher ISP than the chemical rocket engines.

Landing gear is indeed very useful for surface reports!

We know from the latest Devnotes that Ted will be undertaking the daunting task of rebalancing the game, including engine stats. I wanted to open up a discussion on solid rockets. Specifically, I want to discuss the role they play in heavy lifting. IRL, in the case of the NASA Space Shuttle and the SLS, the solid boosters are supposed to provide the majority of the thrust at liftoff. Currently, the largest SRB we have available in the stock game is the S1 SRB-KD25k, which produces the equivalent thrust of a Rockomax Skipper. These boosters came with the SLS parts introduced for the Asteroid Redirect Mission pack and are supposed to represent the five segment boosters used on the Block One SLS. The Block Two SLS is supposed to use "advanced boosters", for which solid and liquid fuelled versions have been proposed. The liquid version is represented in game by the LFB KR-1x2. The solid version is not currently represented in stock, I dug up an article about them at nasaspaceflight.com. In career mode, the early game tech tree is dominated by excellent solid rockets. At the beginning of the game, the RT-10 allows cheap atmospheric and sub-orbital flight. The Rockomax BACC provides cheap first stages for orbital flights and early trips to Kerbin's moons. The S1 SRB-KD25k provides excellent and cheap first stage thrust without even requiring an upgrade to the Research and Development building to unlock it. All of the current SRBs are 1.25m parts. Currently, there are no larger solid rockets for use in heavy lifting. There are 2.5 metre and 3.75 metre liquid fuelled parts designed for heavy lifting such as the Rockomax Mainsail, LFB_KR-1x2, Kerbodyne KR-2L and S3 KS-25x4. However, there are no solids that produce equivalent thrust. This means that any rockets built to lift large payloads must either cluster large numbers of SRBs, or rely entirely on expensive liquid fuelled first stages. One issue that will intrude into this discussion will be the game balance of expendable rockets versus SSTOs in the late game. There will also be a question of whether expendable jet lifter stages are competitive against solids. I personally think that the stock game would benefit from a 2.5 metre solid rocket equivalent to the Mainsail and LFB and available in the Heavier Rocketry tech tree node. Like other solids, it should be cheap, and should have obvious performance disadvantages that make it undesirable for use as anything other than a first stage. Therefore, I think it should have similar thrust to the Mainsail and LFB, should have much worse dry mass and ISP, and should be offered as a cheap "trash bins full of boom" option for a disposable first stage.

Without thinking what I was doing, I accepted a contract to test the Mk 55 Radial engine in orbit right at the beginning of the game. I then had to figure out how to get a spacecraft fitted with a pair of them into orbit within the 17t limit of the tier 1 pad. I pulled it off with just enough fuel to de-orbit afterwards.

If you haven't upgraded the Astronaut Complex yet, you will be offered survey contracts that don't require you to do any EVAs, and therefore don't require you to land. These can be spammed from polar orbit.

Important tip: Ensure that proper range safety procedures are followed at all times! Also, please be aware that in 0.90, you don't need to worry about those silly building upgrades. Patched conics are for weaklings!

After exploring the Mun and Minmus, I've finally unlocked the basic jet engine. Time to accept my first Kerbin survey mission! Off I go to the my first waypoint near the South Pole. Quite a long way to fly in a low altitude jet. Good thing I added these drop tanks. Next, I need to take some EVA reports at various locations in these mountains. Too easy! There aren't too many places to land here. Probably best if I drive instead. Fortunately, the EVA waypoints are all in easy to reach places. I need to get down from this cliff. Too steep to drive down. I'll just find a spot to set down safely. That's the last EVA waypoint. Time to head for home! I didn't have enough fuel to get back, so I found a spot to land near the coast so the recovery ship could come and get me. Job done!

Using tweakables in the Spaceplane hangar, you can remove fuel from the plane's tanks to simulate how the plane's centre of mass moves relative to the centre of lift as fuel drains from the plane. During descent, the plane is probably low on fuel, so the centre of mass will have shifted. If the plane is severely nose heavy, then it will be very difficult to keep the nose up. The plane's centre of lift is also it's centre of drag, so if the plane's centre of mass moves behind the centre of lift, the plane will try to "weather vane" backwards. If the plane isn't too badly unbalanced, it might be able to compensate with reaction wheels and control surfaces. If you suddenly loose control, it might be because the centre of mass moved past a point of no return, or it might be because the plane exhausted it's batteries trying to compensate. Planning how to manage changes in centre of mass can be difficult, as the plane needs to be just as flyable at takeoff as it is at landing.

Where is New Horizons? http://pluto.jhuapl.edu/mission/whereis_nh.php

I wouldn't be surprised if engineers are needed to service drilling rigs and mining equipment for the upcoming in-space refuelling feature. They might also be needed to service life support systems if these are implemented in the future.

I suspect that the capabilities of the buildings in 0.90 have been tweaked to compensate for the absence of the "barn" tier buildings.

Zubrin has already tested the ISRU technology needed for the mission. He considers it to be the lowest tech and lowest risk aspect of the mission. It would be a simple enough matter to demonstrate ISRU ahead of time as part of an unmanned sample return mission. Zubrin checked with the engineers at Martin to see if the relatively small amount of cryogenic hydrogen needed could be properly insulated and stored for the trip to Mars. There would be some boil off, which is accounted for. The hydrogen is only needed for the earlier flights, when a permanent base has not yet been established and a supply of Martian water is not yet available. In Zubrin's book, The Case For Mars, he explains and de-bunks the various "dragons" which supposedly require that a manned mission to Mars be put off until the distant future. Factions within NASA use these "dragons" to justify enormous spending on zero gravity research, radiation effects, human factors research, and advanced propulsion. Each of these different factions are keen to justify their budget, and don't want NASA's main goal to be a manned Mars mission that doesn't depend on them for success. The overriding reason why we haven't sent humans anywhere beyond low Earth orbit since the Apollo Programme, is that there hasn't been a heavy lift rocket available to send them there.

Without going into excessive detail, there has been a theological debate ever since the emergence of Neolithic technology over whether humans should be subject to a static order of nature and obey the "will of the gods", or whether they should attempt to modify their environment to make the Earth more habitable for humans. The creation stories prevalent in western religions depict early humans either as slaves, who must obey the will of the "gods", or as farmers and "gardeners" who are charged with the task of controlling nature to make the Earth more habitable. The first humans are never depicted as paleolithic hunter gatherers. The first argument says that humans should submit to the "will of the gods" and by extension to the will of the religious teachers and rulers that the "gods" appoint to control our lives. The second and very controversial idea is the idea that humans were meant to be intelligent and to possess free will. In the second version of events, humans are meant to become masters of their environment and are meant to "be fruitful and multiply". Think of all of the prophecies of doom that tell us that human meddling with technology and with nature will result in a retaliation that will punish us for attempting to evolve to become better than we are now. Our doom is often depicted as coming from intelligent Frankenstein machines or artificial intelligences that will punish us for daring to become scientifically and technologically literate. "No good will come of this!". Dare to become something better than we are now, dare to overcome the problems that we face today as a species and solve the scourges of poverty, hunger, disease and war, and the universe will turn around and punish us for our insolence. We mustn't at all costs go into space, the dangers are too great and the universe itself will punish us for harbouring ideas above our station. Scott Carpenter derided the brigade of what he called "professional naysayers", who insisted that spaceflight must be fatal to man. There will always be those who insist that human spaceflight is too hard and must be put off forever.

The video explains how to send humans to Venus and return them safely to Earth. It doesn't explain why a manned mission is required or desired. It doesn't make a case for why we would want a permanent base there. To sell the idea of a permanent settlement at Venus, a case would have to be made for how it would fit into the economics and logistics of a developed inner solar system. If Venus can't provide all of the resources needed to support technical civilization, then the Venusian colonists would have to rely on imported resources. These resources would need to be paid for. Could the Venusians produce an export that is of value to the economy of the inner solar system? Mars possesses all of the resources needed to support human technical civilization. This includes food production and industry. It is also within easy delta V reach of the main Asteroid Belt, meaning that Mars could export any goods and resources needed by asteroid miners that they can't produce for themselves locally and can't afford to import from Earth. This would allow a "triangle trade" to be set up, where Mars imports high tech goods and skilled workers from Earth, the Asteroid Belt mining colonies import anything that can't be economically produced locally from Mars, and Earth imports rare and precious metals from the Asteroid Belt that aren't in adequate supply on Earth. A case has also been made for why we would want access to resources from Near Earth Asteroids. The high cost of lifting equipment and consumables from Earth, and the relative ease with which we can transfer between Earth and NEAs makes them attractive sources of in-situ resources. For example, a highly automated process might allow rocket fuel and any other useful resources to be shipped from NEAs to a station in a Highly Eccentric Earth Orbit (HEEO). If such a station could support manufacturing, then potentially most of the hardware and resources needed to get from Earth to anywhere won't have to be lifted from Earth, while the remainder (such as the crew) could be lifted to the station via SSTOs. Making a case for the settlement of Venus needs to be economically realistic. We need to know how self-sufficient a base at Venus could be made to be, and how it would fit in with the economics of a developed inner solar system. If a colony at Venus can provide a valuable contribution to such an economy, then it should be sold on that basis. Unfortunately, the video does not explain what this contribution might be. It should also be noted that in the outer solar system, floating "cloud cities" in the atmospheres of the gas giants could offer an incredibly valuable resource. The atmospheres of all four of the gas giants are rich in the insanely valuable isotope helium 3, which is the second highest energy density fuel known to man behind antimatter, and the highest energy density fuel available naturally in our environment. Helium 3 can be used to fuel highly efficient and clean burning fusion reactors, and also as fuel for fusion thermal rockets. Helium 3 offers such high energy density as a fuel that it provides more than adequate delta V for starship propulsion. It will take longer to settle and develop the outer solar system than the inner solar system, but the potential economic value of helium 3 is so ridiculously high that it will be well worth the trouble.

Mars had liquid water for roughly a billion years or so. It should have had the correct chemistry to allow life to emerge. Mars and Earth have been trading meteorites throughout their histories. Rocks have been blasted off the surface of both planets by asteroid impacts and have travelled through space before falling as meteorites. Despite what happens to the outside of the meteorite, the inside of the rock remains unsterilized. Mars was being hit by unsterilized rocks from Earth containing microbes at a time when it was capable of supporting life. Any microbes that may have evolved on Mars during the same warm and wet period would also have ended up on Earth. Mars is known to have geothermally heated subsurface water. Life can easily survive and thrive in such conditions on Earth, so if there was ever life on Mars in the part, it's perfectly reasonable to expect to find it still living in subsurface water today. The geologically active areas on Mars where we would expect to find such water are releasing methane into the atmosphere. The source of this methane could be geological or biological, but either way, we know that the required geological conditions are present. The only way to know for sure whether there is microbial life in that water today is to use a drilling rig to drill down to the water and take samples. If found, life on Mars may turn out to be descended from ancient Earth microbes that survived the trip to Mars inside a meteorite and subsequently took hold on Mars. In this case, there would be strong arguments for restoring Mars to a warm wet state through terraforming so that life from Earth can once again thrive there. An even greater discovery would be life descended from a completely separate genesis on Mars. All living things on Earth are descended from an ancient microbial common ancestor. If life on Mars was descended from a different ancestor, we would then have two samples of life that emerged independently on adjacent planets. This would prove beyond all doubt that life is extremely common in the universe. Studying alien Martian life would be of immense scientific value and would likely lead to all manner of medical breakthroughs. The final possibility is that Mars might turn out to be sterile. This would support the point of view that life is comparatively rare in the universe and is worth going to great lengths to protect. This would place a burden of responsibility on humans to spread the gift of life across an otherwise dead and empty universe by seeding life on new worlds. Regardless of whether Mars have life now, it most certainly can have life in the future.

This is a link to the updated edition of the full length documentary The Mars Underground. It explains Robert Zubrin's Mars Direct mission plan. With in space refuelling expected in the next KSP update, this seems quite relevant!

I always reckoned that this video was a good example of how to do launch music like a boss.

The pic below shows my "rebalanced" settings for Hard Mode. The building costs are the same as Hard, but the mission rewards are drastically reduced.