Space suits, moon buggies and lunar landers aside - what specific technological advantages (design, computing, navigation, material, engine, thrusters etc.) did the Apollo missions from over 50 years ago have that the Virgin Galactic does not? How specifically would the Virgin Galactic need to be improved so it could do a fly by of the moon?
For a start, I assume it doesn’t have enough fuel - it only goes into very low earth orbit, doesn’t it? Then it would need more to decelerate, more to turn round, and then get back.
Maybe it doesn’t have the life support infrastructure for a journey of that duration. How long does it take to get to the moon and back?
It goes suborbital. To reach orbit, you need to go about 18,000mph (Around the world in an hour and a half). With the best current standard rocket fuels and motors, your spacecraft needs to be at least 90% fuel just to get to orbit. A cheap shortcut is to throw away parts of rocket when they are not needed; most orbital craft, like the gemini, apollo and shuttle, discarded parts to lighten the load on the way up.
See this - Hypersonic: Airbus Dreams of Faster, Greener Space Concorde - DER SPIEGEL and still nowhere near fast enough for orbit.
To get orbital, Spacecraft One would have to be sitting on a tank the size of the shuttle tank, plus a motor on the bottom of that assembly to lift the whole thing. Then it would not be able to be launched from the mother ship, so I would start vertical from the ground with an even bigger tank or a bigger first stage. Pretty soon you’re back to Apollo.
Also, on reentry, the heat disipation needed to bleed off orbital speed is a lot greater than what’s needed to bleed of speed from a simple suborbital flight; we’re back to those clunky tiles again, turning SPaceship One into a flying brick.
All this has only gotten us to orbit. To get from orbit to the moon, we need an extra 7000mph boost. Why fly that giant brick of a renentry craft from the earth to the moon, and down onto the moon? Makes more sense to meet up with a specially designed orbit-to-orbit craft already waiting for you… and a special built throw-away lander.
Apollo got past some of these problems by keeping the humans in a small 10-foot by 13-foot cone which only needed heat shielding on the bottom; and since it too was throw-away, it didn’t matter if the heat shield mostly burned away during renentry. Even then, it was the biggest rocket in history.
It’s not even going to go into orbit. The plan is that it goes up high enough to technically be “in space”, and provide a few minutes of weightlessness for its passengers, then comes right back down.
According to Wikipedia, its planned apogee is 68 miles (110 km, which is a few miles higher than the SpaceShipOne prototype). By contrast, most ships and satellites which actually orbit do so at an altitude of at least 300 km – lower than that, and you run into too much atmospheric drag.
Even John Glenn’s Mercury-Atlas 6 flight (the first U.S. manned orbital flight) had a perigee of 159 km.
For example, Apollo 11:
- Launched on July 16, 1969 at 13:32:00 UTC
- Left Earth orbit for the moon on July 16 at 16:22:13 UTC
- Entered Moon orbit on July 19 at 17:21:50 UTC
So, three days each way, at Apollo speeds.
The height isn’t even the hard part about getting into orbit-- It’s the speed.
The Apollo program ran from 1961-1975, so is not yet “over 50 years ago.”
Also, I think the biggest things they had going for them that Virgin does not were the most powerful MFing rockets ever made.
First of all, the vehicle, built by Scaled Composites, is called SpaceShipOne (SS1). This is the rocket propelled suborbital vehicle, which is carried to the launch altitude by the White Knight aircraft. Virgin Galactic is a company owned by Richard Branson which intends to offer flights on SpaceShipTwo (SS2), the larger follow-on vehicle to SS1. Both SS1 and SS2 have a trajectory that has an apogee of just above 62 miles (100 km), which is defined as the “edge of space” (Kármán line). Note that the motor (which is a hybrid motor; liquid oxidizer and a solid fuel) is exhausted long before that time, and it is in a purely ballistic trajectory until it reenters the atmosphere. At that point it is going much, much slower than orbital speed, so the heating due to ram compression is not high, thus the vehicle has no ablative heat shielding. The elevons and ailerons (or whatever they refer to them as) are use to slow the vehicle down before it hits thicker atmosphere where the heating rate would be higher. This method is not suitable for high speed orbital or Earth injection speed reentry.
Aside from that, SS1 and SS2 do not have the propulsive capability (in total impulse) to achieve orbit or beyond, do not have life support systems suitable for more than a few hours of sustained habitation, do not have communication systems suitable for maintaining voice and telemetry links above low Earth orbit, and do not have a navigation system capable of plotting and assuring trajectory to the Moon. The only way SS1 and SS2 could ever go to the Moon is as payload on another vehicle.
Stranger
So in the 50 or so years since the Apollo missions, various governments, rich oil producing countries, private billionaires and the worlds superbrains have yet to overcome mere fuel and acceleration restraints? When it’s already been demonstrated by Apollo and shown to the world as far back as the 1960’s? Seems like a long time to have not gained an edge in that area.
I’m not sure, but I think the “fuel and acceleration restraints” you’re referring to are more commonly called the laws of physics.
To put it into perspective: SpaceShipOne reached a top speed of Mach 3 or so, which is about 1 km/s. Orbital speed is about 7 km/s. And 7 times faster means 49 times more energy needed to get up to that speed - and that’s ignoring air resistance, which makes it even harder to get up to the higher speed.
Also, these are the speeds the spacecraft reenter the atmosphere. Which means an orbital spacecraft encounters 49 times more heat than SpaceShipOne (assuming the same mass).
The “laws of physics” didn’t seem to slow down Apollo. And speaking of perspective, what do you suppose the collective immaginations of those who were around to witness Neil Armstrong walking on the moon could envision for 2011? A manned mission to Mars? To Venus? To Pluto? A return to the moon at the very least, no? Yet here we are flying around in glorified airplanes that can’t get orbital? What is holding us back?
That would be gravity.
Money. Not technology. Just money. Sadly, Americans will never allow tax rates to return to the levels they were at in the 1960s that made Apollo feasible, and there’s just not enough financial incentive for the private sector to leave Earth orbit.
And lack of funding. Anyone could replicate Apollo given enough money (almost $200 billion in today’s dollars) and time.
Understood (and agreed); I was mostly responding to Candyman74, who asked about it going into low-Earth orbit.
Lack of impetus likely also plays a role.
In the 1950s and the 1960s, NASA and the space program were able to command massive funding, because we were in a race into space (and then to the moon) against the Soviet Union. Getting to the moon – and getting there before the Soviets did – was seen as an important strategic advantage by the U.S. government and military.
Today, there’s no country which holds that same “bogeyman” status. The Russian space program relies, in no small part, on our funding just to keep going. While the Chinese are aggressively building their space program, the U.S. isn’t engaged in a Cold War with them, and they’re (at the moment) simply retracing things which we have already accomplished.
The lack of any real need or purpose to expend the extraordinary amount of effort and accept the risk of sending people to far flung interplanetary destinations (and bring them back), versus sending unmanned probes that can operate in a wide variety of environments that would be hazardous or lethal to human beings (and not have to bring them back). We’ve gotten an enormous wealth of data from the various interplanetary programs, especially the Mars Exploration Rovers and the Jupiter and Saturn missions like Galileo and Cassini, and all for a fraction of what it would cost to put a single person on the surface of Mars.
And I guarantee that there is no manned mission that will ever go to the surface of Venus.
Stranger
According to the little ticking clock I found on the internet, the US has spent $434,000,000,000 ish in Afghanistan. We could have gone back twice!
Probably few of those imaginations envisioned how effective robotic probes would become, at a tiny fraction of the price of manned missions. Principally due to the cost, a manned mission to Mars isn’t yet under serious contemplation, but we’ve explored the surface in more detail than any such mission probably could.
You knew of a way to divert this sum from the DoD to NASA, and yet you kept it to yourself?