Another reason is the Van Allen belts. This zone of radiation is best crossed quickly as spending too much time in it can kill the crew. That being said you could send something like Orion to a High earth orbit or EML-1/2 with 2 delta heavy launches (one for Orion, one for a stage). Or one FH launch (Orion plus stage lifted together). Once there it could meet another craft that was moved via electric propulsion from LEO.

You need chemical propulsion, and you may need heavy lift. However the amount of heavy lift needed depends on both technology and mission. Apollo needed its Saturn V because it didn’t use depots and needed to send both crew and lander at the same time fully fueled. If you change that equation, then smaller launchers can work that is where things like fuel depots and electric propulsion help.

There is really no other user for a 100MT+ rocket at this time. Only NASA could use it (and they can’t afford it). If your heavy lift is designed in a way that others can use it like say the FH, then NASA isn’t bearing all of the costs to keep the capability around. If you only doing 1-2 BEO mission a year, then EELV or EELV derived heavy lift(Delta phase I, Atlas Phase I or II) make much more sense.

A good example would be Apollo. For Apollo you needed to lift a 30MT CSM and a 14MT lander at the same time.

If you had an SEP tug, you could send the lander ahead to EML-1, now you only need to send the capsule to EML-1. That could be done via a 70MT heavy lift (if you restrained yourself to one launch). Orion actually masses 21MT or so and with a 25MT or so upper stage could go to EML-

A FH could lift that much at once or it could be done in two launches of Delta Heavy. To be fair lunar lander departing EML-1would need to mass more say 20MT but that is another story.

If you had a Fuel depot at EML-1, it becomes possible to reuse the lander. Instead of sending a new lander every time you send cheap propellant and supplies via the SEP tug. You can lift 20MT via Atlas, Delta or FH.

You now can do a lunar mission with 2-3 launches of existing rockets that don’t cost NASA 3 billion a year just to have the capability. The focus shifts to spacecraft not rocket, which is where it needs to be.

“Ron, don’t know if you caught this.”

I hadn’t, so thanks for the update.

I’ve long been a fan of VASIMR, and I too can’t wait to get the test engine up to the ISS and do some real-world operations.

My only point to “niksus” was that we don’t need to wait for newer engine technologies to explore, just like the Wright Brothers didn’t need to perfect heavier-than-air flying to start flying.

The best way to know what the technologies we need to improve is to gather real-world experience on what is holding us back (or costing us too much), which is part of what the goal of the ISS is. So too when we get our first beyond-LEO exploration vehicles going, we’ll find out what mix of technologies work and which ones we want or need to improve upon.

VX-200 VASIMR Prototype Increases High Power Performance, Demonstrates Efficient Constant Power Throttling

“The June 2012 campaign successfully accomplished this task, producing a new optimized performance model that shows approximately a 10% improvement in engine efficiency over a wide Isp range.”

The second part is interesting also:

“2. Demonstration of efficient Constant Power Throttling (CPT)

The throttling that makes VASIMR (R) uniquely distinctive from other in-space propulsion designs is its ability to vary the plasma exhaust parameters (thrust and Isp) while operating at a fixed total power level. This technique, called “Constant Power Throttling (CPT),” is similar to the function of a transmission in an automobile. Using optimal CPT for different phases of a mission, VASIMR(R) is capable of increased payload mass and decreased trip times compared to other technologies.”

Increased performance and increased payloads. Can’t wait to see the test results when they put this on the ISS.

“Imho, earthlings don’t need chemical rockets for deep space missions.”

But chemical engines and technology is what we know, and we could do deep space missions with chemical engines today if we had to. Electric engines could lower the overall cost of the transportation segment, but they raise the cost of the human payload portion (longer mission = more supplies/weight).

But we shouldn’t jump directly to Mars without testing our ability to roam around in local space, which is why I think a mission to an asteroid is so important – to test out our theories on what are the best combinations of technology and technique to travel long distances safely and least expensively.

The people who would be interested in doing it NASA, Bigleow, Excalibur Almaz, ect already know that. An communications satellite needs something to communicate with and I really don’t see a massive program to pepper the far side with probes happing that would justify it.

They only need one far side probe.

As for a store and forward satellite in low lunar orbit it is not significantly different in cost compared with an ordinary communications satellite at EML-2.

Ah the way they do it at mars is they send the data from surface missions like MER and Phoenix to either Mars Odysseys or Mars Reconnaissance orbiter, even Mars express once. The data is then stored and relayed back to earth when those probes have a view to earth. Granted MER and Phoenix could send data directly back to earth if there were a need but that is a different story.

“The Dragon is not man rated yet so people cannot be sent on a loop around the Moon. However a cargo loop can go near EML-2.”

Err not quite. NASA plays no role in non NASA spaceflight, only the FAA. Dragon may not yet be able to carry a crew, but it soon will be (circa 2014). If Space X flew a lunar mission before Orion, it could cause a deep reevaluation of the way spaceflight is done and perhaps even if NASA is needed anymore. They certainly would be able to test an unmanned one around the moon very quickly if they wanted to.

“Before EML-1 or EML-2 spacestation gets built we need to get someone to agree to pay for it. A communication satellite there shows that it is a useful piece of real estate.”

The people who would be interested in doing it NASA, Bigleow, Excalibur Almaz, ect already know that. An communications satellite needs something to communicate with and I really don’t see a massive program to pepper the far side with probes happing that would justify it.

“This will also tell the general public that NASA can go the Moon and Mars.”

The general public knows that. They don’t want to pay taxes to NASA to send someone to the moon or mars without very good reason. Unlike roads, education, heck even the military, HSF makes little to no impact in the everyday lives of people. That is why many see it as a waste. IMHO that must change. By doing it privately you start doing things without (or with as little as possible) their taxes. You can develop missions and systems with less political bantering.

Nah. You could just use a probe orbiting the moon to act as a relay (like we do at mars). Plus unless space X gets into the communications business, NASA pays for it or someone else does no revenue stream.
However a loop around the moon is the perfect tourist type trip of sorts. FH can push 16MT to TLI. If dragon could carry 3 tourists plus a pilot with a launch cost of 128mil and the cost of dragon roughly 54 mil, you could sell seats for roughly 60million.

A single communication satellite orbiting the Moon cannot replay back to Earth from the far side unless it is a long way out. To see both the far side and Earth continuously a EML-2 HALO orbit is needed.

The Dragon is not man rated yet so people cannot be sent on a loop around the Moon. However a cargo loop can go near EML-2.

As for space station at EML-1 or EML-2. All you need it for someone to build and launch one.

Before EML-1 or EML-2 spacestation gets built we need to get someone to agree to pay for it. A communication satellite there shows that it is a useful piece of real estate.

SpaceX is still part owner of Surrey Satellite Technology Ltd ?

Unfortunately that press release is out of date. From Wikipedia “Surrey Satellite Technology Ltd, or SSTL, is a spin-off company of the University of Surrey, now fully owned by EADS Astrium, …”