Nibb31

If the stage is on a free fall trajectory that ends at a landing pad and you blow it to pieces because the engine doesn't start, then you only have a whole lot of rocket bits that are still going to end at the landing pad. You'd really want to divert the rocket, which you can't do if the engine doesn't start or you've lost control. The best solution is to aim for a crash area, and divert the rocket to the landing pad when you are sure that everything works.

Yep, but their facility is sized for a production rate of 400 Merlins per year, which means that they are wasting money on an oversized factory. Only SpaceX management can do the proper cost/benefit calculation for reusability, and they can only do that after they have some experience in actually recovering, refurbishing, and relaunching. For all we know, the stress of reentry might cause buckling or unrepairable stress marks on the tankage, which might make the whole enterprise unviable. Nobody knows at this point. My point is that it is not as clear-cut as some people seem to think. Reusability only makes sense if you dramatically increase the launch rate and the refurbishing costs are minimal. The launch rate can only increase if there is an increase in demand. A 20% cut in launch costs is not going to suddenly create a massive demand for orbital launches.

That is one example. However, microgravity research hasn't really piqued the interest of pharmaceutical companies to the point of making them invest in orbital science. Although the idea of using microgravity for developing new drugs has been bandied about for yours, the truth is that not a single pharmaceutical company has even launched a cubesat or flown an experiment to the ISS. They simply are not that interested. No. Infrastructure and manpower to develop the vehicles, handle them, maintain them, integrate payloads,fuel the rocket and payload, monitor launch and pre-launch activities... And there is also the administrative and sales overhead. There are thousands of people that work at SpaceX and the various NASA space centers that have nothing to do with manufacturing. In fact, the manufacturing facilities are only a small part of the whole thing, and don't typically employ the most expensive employees. On the other hand, reusing hardware means that you build less of them, which in turn means that the unit cost of each item is much higher because you don't benefit from economies of scale. If you build 10 rockets a year instead of 100, then the cost of each rocket is much higher. You don't divide your costs by 10. Overall, the cost of the first stage hardware is only a fraction of the total launch price. Reusing that hardware only saves you a fraction of the cost of that hardware. And remember that the launch is only a fraction of the cost that a customer pays to build and operate a satellite. In the end, you are looking at a reduction of the price of a launch of 20% max, if you're lucky, which means that customers might save $10 million out of the current $60 million they pay to launch their $300 million satellite. It's an appreciable reduction, but it's not going to revolutionize access to space. I don't think it can be done much cheaper than what SpaceX does today. They are cheaper because they are run with lean processes, subsidized technology, and a young and overworked workforce. But they are about as lean and mean as it can get without taking uncontrolled risks. There are no miracles. You're talking about a 95% reduction in launch costs. That is simply isn't realistically possible with any current technology. And Virgin is a technological dead end with an elitist business model. Jetsetters are interested in going to space because it's rare. Once half of the jetset has flown on Virgin, it loses its novelty appeal.

Not comparable. When powered flight developed, there was a huge demand for mass transportation. People needed to reach destinations where they would be able to conduct business, meet with relatives, find a job, build a new life, or just visit. None of that demand exists for spaceflight. There is nothing for normal people like you and me to do up there, except float around and look out of a window. There is no business, no new life, no cheap resources. No. Reusing the first stage does not cut cost "immensely". The cost of the hardware is a small fraction of the total cost of launching a payload into space. The biggest cost is infrastructure and manpower, which are not really impacted by reusability. It will be interesting, but accelerating payloads to orbital speed will always require large amounts of power. That kind of power will always cost a lot to produce, handle, and transform into kinetic energy in a safe and secure manner. - - - Updated - - - You need to return it to the launch site somehow. The second stage practically gets to orbit, which means that you might as well do a full orbit and land at the launch site. If you land it downrange, it doesn't change much in terms of deorbit and reentry, but you also add the cost and delay of bringing back the stage on a plane or a ship. Those options are not cheap and go against your goal of "fast turnaround". The second stage is pretty small, with only one engine. It's much cheaper than the first stage to produce, so it really doesn't make sense to spend more money to recover it.

There was no point. They had invested in the recovery system and salvage ships at the beginning on the program, so there was no turning back. The reason was the political claim that everything was reused except the external tank.

None of those things are "CURRENT" technology AFAIK.

An SRB is basically made of steel casings (the cheapest part), solid propellant casting (the most expensive part), avionics, thrust vectoring systems, ignition systems, separation systems, and parachutes. The SRBs were salvaged at sea by two recovery ships at great expense, taken apart, and only the steel casings were reused. It wasn't very economical at all.

1- They use computers. However, they typically work in reverse to what we do in KSP. Instead of launching the rocket and figuring out how to get to the destination from there, they determine where they want to put the probe, the various dV options to put it there, and work their way back to launch. 2- The extended mission objectives are vaguely outlined before the mission. It's not secret, but the details are decided on an "as we go" basis, depending on where they are, what they found, and whatever resources (time, money, power, propellant) are left.

If they are clever (and they usually are), they put the first stage into a flyback trajectory that ends in a crash zone (ocean, marshes, etc...). If the engine restarts properly, then it diverts to the landing zone. This is for the first stage. Flying back the second stage is impractical. The only time it was mentioned was in that "Muse" inspirational video from several years back, but everyone including SpaceX knows that it's not worth the propellant penalty and extra weight. The second stage has to reach orbital speed to return to the landing site, so it would need a pretty heavy heat shield to survive reentry, which would severely reduce the payload fraction.

Not really, the ISS is held together with CBM ports and APAS/hybrid docking ports. The PMA between Unity and Zarya is only an APAS.

Source please ?

Not a reactor. It was a small RTG.

It's a possibility if those missions ever get funded.

Not really. Docking ports have mechanical specifications and limits. And designing a new system is a very long process. Just look at how convoluted the LiDS/NDS/IDA development has been. It started in 1996 with several redesigns and a lot of money spent. You don't just "make them bigger".

That's not a maglev, it's an automatic light railway. It looks a like the VAL that is used in my city:

You would start it like any other company. Of course, before you get started, you are going to need a business model, a potential market, and to hire the right people.

This is a view from the top facing window, with the camera pointed upwards. It would depend on the desired reentry profile. During this flight, the reentry profile was steep, to simulate the heat from a lunar reentry.

French Aerotrain jet-powered air-cushion monorail from the 60's. 30 kilometers of test tracks were built and it managed to reach 400 km/h. And the old TGV. Orange was super-trendy in the 80s. Those TGV trains are 35 years old now (older than the Space Shuttle!) but they are still going strong.

They would probably try to troubleshoot the problem and wait for ground teams to reestablish comms. Visiting vehicles also have their own independant and redundant comm systems, so they would probably power up the Soyuz and try using that. They might try juryrigging their gear to contact HAM radios or something. If nobody answers, then I guess Earth is toast. If the situation became untenable or dangerous (lack of attitude control, supplies, or critical information), then I suppose the decision would be made to evacuate. For example, after a while it might be risky to stay on board without debris monitoring information. It probably is. Firing thrusters on Zarya would result in a bad day for Zvezda. I don't thing they use its RCS pods though. They spend a lot of effort trying to minimize pollution from thruster exhaust in the vicinity of the ISS. Yes, you're right. In fact it's called "hybrid", a probe and drogue system with an APAS docking collar.

Most of the ISS systems are controlled by various laptops that are located around the station. Each laptop can access all systems. The closest you'll find to a "cockpit" is the Cupola module, which is a wide window bay that is used for observation, monitoring docking/berthing operations and simply daydreaming... Manoeuvers such as rotation, reboost or avoidance, are usually scheduled and controlled from the ground. There are two airlocks on the ISS: The Quest airlock module on the USOS and the Pirs module on the Russian segment. The spherical parts on the Zarya and Zvezda (where the other modules dock) can and have been used as airlocks, in contingency situations. Only the Russian modules Zvezda and Zarya have RCS, but I don't think those are functional any more. Those modules were essentially individual spacecraft that could fly and dock independantly. That is not the case with USOS modules (US Orbital Segment, including European and Japanese modules), which are basically dumb canisters. Attitude control is done through CMG (control moment gyroscopes), located in the truss. These are basically a set of heavy flywheels that spin up and down on several axes, which rotates the station in the opposite direction. Reboost is done by visiting craft (Progress or ATV). No, systems are redundant. It would be pretty hard to actually lose contact with Mission Control though. Comms go through redundant channels, including the TDRS satellites and ground stations around the world. Each country has independant communication channels and mission control centers. The USOS and global systems are controlled from Houston, but the international modules have their own Mission Control centers in Russia, Europe, and Japan. If one channel was to go down, communications would go through someone else's module. There are lots of docking ports, using different systems. The Russian segment has at least 3 hybrid docking ports for visiting Soyuz and Progress vehicles. At least two of those are constantly used by 2 Soyuz spacecraft that also serve as lifeboats in case of emergency. The USOS has 2 APAS ports which were used by the Shuttle, and are soon to be equipped with IDS adapters (the new international standard) for CST-100 and Dragon. And there are several CBM ports, which can't be used for docking, but allow visiting vehicles to be berthed with the robotic arm (for Dragon and Cygnus) or new modules to be attached.

One of the worst rocket explosions was the Intelsat 708 launch on a Long March 3B in 1996. Officially, the disaster killed only two victims. However, videos of the aftermath taken by westerners after the crash show that the base's residential area and a nearby village, less than 2km from the launch site, were devastated by the explosion. Many people believe that the death toll was much higher than any other rocket disaster.

First, GEO is not "Near Earth Orbit". It's pretty far away, and the only practical use of GEO at the exact GEO altitude. The graveyard orbit that is above it is useless for any practical purpose. Secondly, if you want a commercial space industry, then it's all about "saving bucks". If it wasn't economical to operate GEO sats, there would be no space industry at all and government launch prices would be prohibitive. If a GEO sat had to carry enough fuel to put itself and into GEO and to do a controlled deorbit from GEO, then it wouldn't spend enough time in operation, so it wouldn't be economical, and wouldn't exist in the first place.

The thread title mentions the 50s and 60s.

It might also be due to optimized plumbing.

Johnson Space Center predates Kennedy Space Center. Mission Control was moved to Texas because that where most of the aerospace engineers were located. Astronauts spent most of their time training in Houston. KSC was only where the integration and launch activity took place.