SpaceX Dragon spacecraft for low cost trips to the Moon.

On Feb 3, 6:06*am, Alan Erskine wrote:
On 2/02/2012 8:54 PM, Robert Clark wrote:

* You can send it to this email address. What are you using for your
Earth departure stage and lunar lander stage?

* *Bob Clark

Forgot to add - Nothing exists that's powerful enough for what I call a
Trans-Lunar injection (see, nothing original there either) stage, but
I've used two MB-60/RL-60 engines.

I looked over your presentations. Looks good. I definitely think your
low cost estimates to go back to the Moon are doable.
However, about your Trans Lunar Injection stage, my understanding is
that since that is launching from LEO in zero G, you don't need the
engine thrust to exceed this upper stage's gross mass. Usually in fact
for upper stages it does not, even for stages sending a satellite to
GEO, which is a comparable delta-V requirement to that of sending a
satellite to low lunar orbit.


Bob Clark

On 9/02/2012 6:04 AM, Robert Clark wrote:
On Feb 3, 6:06 am, Alan wrote:
On 2/02/2012 8:54 PM, Robert Clark wrote:

You can send it to this email address. What are you using for your
Earth departure stage and lunar lander stage?

Bob Clark

Forgot to add - Nothing exists that's powerful enough for what I call a
Trans-Lunar injection (see, nothing original there either) stage, but
I've used two MB-60/RL-60 engines.

I looked over your presentations. Looks good. I definitely think your
low cost estimates to go back to the Moon are doable.
However, about your Trans Lunar Injection stage, my understanding is
that since that is launching from LEO in zero G, you don't need the
engine thrust to exceed this upper stage's gross mass. Usually in fact
for upper stages it does not, even for stages sending a satellite to
GEO, which is a comparable delta-V requirement to that of sending a
satellite to low lunar orbit.


Bob Clark

I'll have a look at it. If that's the case and you are right, it's a
big mass saving and further increases payload; that'd be very very handy!