Shpaget

Do you see those holes for the mounting bolts, those lines between strips, bubbles of air trapped under the foil and holes he poked in it to pop them? Yeah, those will ruin the picture. I already gave you the only way you can make a parabolic mirror that is good enough for optical telescope. There is no other way.

That sounds like a good design of the NS and an oversight/compromise/tradeoff in the F9/Merlin design. SpaceX could decide to decrease total thrust/payload capacity and install a smaller central engine so they can hover as well. They choose not to, so they have that problem. Dissing an accomplishment of one because of shortcomings of a competitor is not nice.

Tolerances for satellite dishes are much poorer than for optical telescopes. Your dish could be banged up and have bird droppings all over it and still perform ok, something that would completely ruin an optical mirror. Are [I]you[/I] able to develop the liquid that will become reflective once it solidifies? If not, are you able to pay someone the cost of development? The cost of such development would probably be such that you could buy a fully equipped observatory instead. Mirror can't be translucent. The reflective surface must be on the front, not back (the first thing light hits must be the reflective stuff, not transparent glass). Polishing and coating is the way it's done. You can grind, polish and figure the base yourself. It's usually done in glass. Then you pay a company that specializes in such work to coat it for you.

It's perfectly possible to do all the steps to make the mirror in your back yard, except the final reflective coating. To get the good job on that one, you'll need some equipment that is beyond amateurs. However, there are companies that will do that relatively cheaply for you. To make the mirror you need just some basic tools. [url]https://stellafane.org/tm/atm/general/myths.html[/url] [url]http://stellafane.org/tm/atm/index.html[/url] Also, don't entertain the idea of the satellite dish. That's nowhere near good enough.

I'm unable to find detailed profiles, but from what I did find, the barge is about 400 km downrange. While that may sound a lot, it doesn't really matter because most of that downrange travel is done on ascent, not descent. The lower stage does not come horizontally at the barge. In conjunction with grid fins, it performs multiple burns high up in atmosphere to adjust the trajectory, at which point the F9 and NS profiles become very similar - almost vertical.

[quote name='*Aqua*']Jupiter is the main reason for reduced pertubations. All that's left in our solar system is those stuff which bowed to Jupiter's gravitational forces and are now hold unter it's control in (semi)stable orbits.[/QUOTE] No, it's more or less stable [I]despite[/I] Jupiter's influence; not thanks to it. [quote name='*Aqua*']Everything else already crashed into something or was catapulted out of the system.[/QUOTE] Everything else crashed into something or got ejected [I]because[/I] of Jupiter. Without big massive objects to cause significant perturbations, orbits of the small ones follow almost perfect elliptical paths. They don't wander off unexpectedly.

New Shepard did not land just anywhere. It landed on a small target. It is directly comparable to landing on the barge. It also landed right smack in the middle of that target. [IMG]http://i.imgur.com/YaUzusV.png[/IMG]

[quote name='kiwi1960']Because the molten core, without the mass of the planet, would become unstable and explode. [/QUOTE] A molten core is not going to spontaneously explode. Here's a video of it not exploding. [url]https://www.youtube.com/watch?v=ntQ7qGilqZE[/url] [quote name='kiwi1960'] As for the gravity question, its not a simple case of the sun holding it all in place, ALL the planets have an effect on the other planets .... take one out, and the equations change... even a minute change is still a change.... but take out the Earth.... what happens to the Moon.... and so on.[/QUOTE] The Sun holds almost 99.9% of the mass of the Solar system. Aside from Jupiter, rest is negligible. Taking one planet out, even Jupiter, would [I]reduce[/I] perturbation or others, not increase it.

[quote name='gooddog15']I don't think it's fair to compare New Shepard to the falcon 9. One's a suborbital rocket, while the other is strictly orbital.[/QUOTE] F9 return stage is never orbital. [quote name='gooddog15'] New Shepard is just peanut's compared to the Falcon 9.[/QUOTE] So F9 has more room for computer, navigation and guidance hardware. Is that what you're saying? [quote name='gooddog15'] Sure, NS flies all the way to space and back, but so can any first stage with a simple capsule thrown on top, just without you know, the successful recovery part. The Falcon 9 is a first stage and is strictly a first stage, throwing up the weight of a second stage + payload[/QUOTE] Smaller rocket - smaller payload. It's proportional. NS is also a first stage and strictly a first stage, throwing up the weight of its payload - second stage. [quote name='gooddog15'] high up in the atmosphere at a velocity of nearly 2.0km/s prior to deceleration and final touchdown on a [I]freaking[/I] barge in the middle of the [I]freaking[/I] ocean. Meanwhile, NS flies up to 100 km, separates it's capsule, falls back down and lands somewhere in Texas. [/QUOTE] Not somewhere in Texas. Exactly on the targeted landing area that happens to be smaller than the barge. BTW, what's your estimate, how fast is NS going? [quote name='gooddog15'] Besides Space X *technically* did it first [/QUOTE] No, they didn't. They crashed. [quote name='gooddog15']only to tip over and blow up after a second or two of being stationary. [/QUOTE] Nope. It was never stationary, or even upright. [quote name='gooddog15'] Blue Origin New Shepard landed in [I]Texas[/I], where everything is big, with it's wide open spaces and all. [/QUOTE] And the barge in the middle of the ocean is surrounded by skyscrapers that hinder the approach?

I've been looking for that film for years!

Engines on the Apollo landers were throttleable to about 10%.

The dust is from retrorockets. [url]https://www.blueorigin.com/technology[/url] [QUOTE]The crew capsule descends under parachutes for a smooth landing, in the same way as the earliest space pioneers. Three independent parachutes provide redundancy, while a retro-thrust system further cushions your landing.[/QUOTE] Soyuz does the same. [url]https://www.youtube.com/watch?v=XyvIw_yO60w[/url]

[quote name='FishInferno']Enough safety features to pull the crew away safely in the event of an explosion (read: every spacecraft except the shuttle)[/QUOTE] Let me repeat myself. There is no such thing as "enough safety features to prevent an accident". There is only "enough safety features to reduce the risk of an accident to an acceptable level". Which is exactly what has been done.

What's this talk of CGI?? I see only a segment of 20 seconds of CGI that is clearly not intended to deceive, but rather to represent the intended mission. The separation of booster and pod, the only technical part of that segment, is obviously CGI which would be insanely difficult to film from that perspective and no one in his right mind would mistake it for actual footage. The important part, the landing itself is, as far as I can see, completely video footage, no CGI at all. Those people made a significant achievement and I don't understand the dissing.

How did you get the energy requirements for disassembly? Also, how do you define complete disassembly?

It appears it still takes several seconds to cut the power. Anyway, the suicide burn doesn't seem to be a problem for powered landing. Their timing was quite good the last time they got to that phase.

A mostly uniform disk shaped asteroid belt, such as main belt and Kuiper belt and spherical formation such as Oort cloud will not alter the position of the barycenter.

That's a recurring theme in fiction. Battlestar Galactica, Stargate, Star Trek (if you consider the Borg to be bots)...

[quote name='kerbiloid']Kethane mod contains a ready-to-use KE-WAITNONOSTOP-01 Kerbal Unreconstitutionator converter which you can use to convert Kerbal into Kethane in situ.[/QUOTE] That is simultaneously the most disturbing device ever made, and a very noble one. As for the original question, it's hard to answer. If you're limited to use nothing but a human, then [I]very[/I] little. There is very little unreacted oxygen available for combustion, so without adding additional oxidizer, you won't be able to extract much of the energy. If you can use additional oxidizer and some king of an engine, then the numbers go up, but with that logic you can use the body just as reaction mass (with necessary energy and hardware provided), at which point dV is theoretically unlimited.

[quote name='Gaarst']Actually, if Jupiter disappeared that would be really bad for us: most asteroids in the Asteroid Belt are kept in their place by the gravitational pull of Jupiter, without it they would be less stable and end up crashing on our heads.[/QUOTE] I'll have to ask for citation for that one.

Why would it explode? Also, the Sun contains 99.86% of the mass of the solar system. Even if Jupiter with its moons just disappeared, it would have negligible effect on the rest of the system. BTW, does the goo come in neon green?

I got confused when you said "Now we clearly agree that certain non-conservative forces (e.g. friction, B) can take energy out of the system, viz. reduce T. ". To take the energy out of the system you need to act upon the system from outside of it. Friction inside the system does not take the energy out of it. In your case of P = m1v1 + m2v2 v1 = -v2 P = m1v1 - m2v2, and if m1 = m2 P = 0 It was 0 from the beginning. Ninjaed

But that's outside force.

Torque induce precession of a flywheel does not depend on gravity.

[quote name='Jovus']One thing I don't understand still is why we don't use friction to dump angular momentum from our reaction wheels. Yes, conservation of angular momentum, but that only applies to conservative forces. Friction is not a conservative force.[/QUOTE] Propose a model that would produce a net change in angular momentum.