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Re: SpaceX News

Posted: Mon Mar 13, 2017 1:56 pm
by Skipjack
I think that sustaining a mars colony is unfeasible until the average trip time to mars is less than a month. The fact that we are still struggling with just going to the ISS, tells me that even a sustainable moon base is still way off. It would be very wise to invest in break through energy/ propulsion technology first, which would have other benefits as well.

Re: SpaceX News

Posted: Mon Mar 13, 2017 3:24 pm
by Carl White
Skipjack wrote:The fact that we are still struggling with just going to the ISS, tells me that even a sustainable moon base is still way off. It would be very wise to invest in break through energy/ propulsion technology first, which would have other benefits as well.
I wonder whether that's a matter of actual difficulty of doing it, or just not being willing to put enough resources into doing it.

Re: SpaceX News

Posted: Mon Mar 13, 2017 4:41 pm
by JoeP
Probably the latter. IIrc, some ion designs are estimated 1-2 months trip time.

Re: SpaceX News

Posted: Tue Mar 14, 2017 8:37 am
by NotAPhysicist
I'm willing to go with Elon Musk's take that the main problem at this point is launch cost.
Get costs down low enough and people will be willing to put a lot of stuff in to space - the distance/time is important but if you can chuck a lot of resources at the problem it becomes less of an issue. So rockets based on newer techniques and resuseability. Fortunately that is being tackled by more than just SpaceX so that's handy.
Not that I'm against lots of investment in more advanced energy generation or breakthrough propulsion schemes, far from it.

Re: SpaceX News

Posted: Wed Mar 15, 2017 12:43 am
by Skipjack
Carl White wrote:
Skipjack wrote:The fact that we are still struggling with just going to the ISS, tells me that even a sustainable moon base is still way off. It would be very wise to invest in break through energy/ propulsion technology first, which would have other benefits as well.
I wonder whether that's a matter of actual difficulty of doing it, or just not being willing to put enough resources into doing it.
There are many potential solutions to the problem. Some are more conventional, like what Musk and Bezos are trying to do. Then we have Sabre and REL. Then there are other more risky, but potentially a lot more rewarding approaches. As we are all aware of, there are quite a few fusion based propulsion concepts that could mean a break through for transportation below earth orbit. Some could even mean a break through for launch to orbit. And of course they would solve the world's energy problems as the same time.

MSNW LLC's Fusion Driven Rocket is predicted to enable trip times to mars as low as 30 days, which is the lowest I have seen so far.
A recent addition is Shumlak's Reverse Flow Z- Pinch which could (if it works as anticipated) lead to ~200 MW device with a volume smaller than 4 m3 (Cylinder 2 meter diameter and 1.5 meters tall). Something this compact would have lots of applications including aerospace.
I also find Sam Cohen's FRC- based Direct Fusion Drive quite promising. It also has the potential to be very compact and light weight. Cohen's reactor would be most aneutronic too, which helps with weight.
There are a few other promising fusion reactor concepts (including Polywell) that could lead to other fusion based propulsion schemes. Miley et al have looked at quite a few and checked them for their potential.
Anyway, I think that colonizing mars or even the moon before we can even get to LEO without a huge and expensive struggle is premature. A propulsion and energy break through would be a game changer. IMHO, this is what NASA should focus all it's efforts on, instead of throwing money after the stupid pointless SLS. The amount of fusion research that could have been funded with the billions thrown into that money grave...

Re: SpaceX News

Posted: Thu Mar 16, 2017 12:29 pm
by krenshala
It looks like the SpaceX launch went off fine this morning, after being scrubbed on Tuesday morning due to high winds.

Re: SpaceX News

Posted: Fri Mar 17, 2017 1:02 am
by Skipjack
It seems like all future launches (except probably those reusing previously recovered stages) are going to use an improved Falcon 9 that requires less work with the range. That should help with range related delays.

Re: SpaceX News

Posted: Fri Mar 17, 2017 12:50 pm
by ladajo
The next SpaceX (March 27?) is the money shot.
First reflight, and with a commercial payload.

Re: SpaceX News

Posted: Fri Mar 17, 2017 2:39 pm
by paperburn1
This next one does not land as well , correct?

Re: SpaceX News

Posted: Fri Mar 17, 2017 2:59 pm
by TDPerk
paperburn1 wrote:This next one does not land as well , correct?
No, it is a refurbished launcher intended to be landed and used a third time.

Re: SpaceX News

Posted: Fri Mar 17, 2017 3:34 pm
by ladajo
Yup, as I understand, there are no more 'unlegged' boosters. Everything going forward is recoverable. I believe this is also the case for heavy and deep pushes to Geo (or beyond), as the landing platforms have proven out for deep sea ops. Thus, this gives them ability to position for a long arc shot, to landing, saving fuel landing requirements on the booster. In addition, the newer engines and superfreeze LOX help this out as well.

Re: SpaceX News

Posted: Fri Mar 17, 2017 4:30 pm
by krenshala
It will definitely save on fuel for the landing if they don't try to reverse the ballistic arc. And that means more for putting the second stage where they want it. Hopefully the next one won't be on a day I work (or the night before), so I'll have a chance to see how it goes as it happens.

Re: SpaceX News

Posted: Wed Mar 22, 2017 4:28 am
by paperburn1
n this mission, we also get to meet the newest member of the SpaceX family: the "Roomba". The SpaceX Roomba is an adorable low-profile tracked crawler robot which lives inside a protective "garage" on the edge of the droneship (landing barge). After the stage lands on deck, Roomba will scurry out of its garage, trailing a bundle of umbilical lines, crawl underneath the rocket between the landing legs, and attach to the base of the stage.

Roomba appears to have four hydraulic jacks which will interact with the hold-down flanges on the thrust structure of the rocket stage. We're not entirely sure whether it lifts the stage up or pulls downward. But its purpose, in a vague sense, is to secure the rocket after landing, to correct for any static tilt, and to prevent the vehicle from "walking" along the deck as the barge pitches and rolls with the waves in the ocean. :?: :?: :?: :?:

Re: SpaceX News

Posted: Wed Mar 22, 2017 12:42 pm
by TDPerk
paperburn1 wrote:n this mission, we also get to meet the newest member of the SpaceX family: the "Roomba". The SpaceX Roomba is an adorable low-profile tracked crawler robot which lives inside a protective "garage" on the edge of the droneship (landing barge). After the stage lands on deck, Roomba will scurry out of its garage, trailing a bundle of umbilical lines, crawl underneath the rocket between the landing legs, and attach to the base of the stage.

Roomba appears to have four hydraulic jacks which will interact with the hold-down flanges on the thrust structure of the rocket stage. We're not entirely sure whether it lifts the stage up or pulls downward. But its purpose, in a vague sense, is to secure the rocket after landing, to correct for any static tilt, and to prevent the vehicle from "walking" along the deck as the barge pitches and rolls with the waves in the ocean. :?: :?: :?: :?:
I recall observing they needed something like a forklift to scoot out and hold the rocket ASAP after landing. Looks like they thought so too, more or less.

Re: SpaceX News

Posted: Wed Mar 22, 2017 11:33 pm
by paperburn1
The last rocket that landed slid almost to the edge of the barge before they were able to get aboard and secure the landing pads. It takes almost an hour to get the crew onboard the barge after landing.