Recent Posts

Pages: [1] 2 3 ... 10 Next
Excerpt of letter to NASA from Congress, dated yesterday (this sort of NASA stone-walling is exasperating):

"Finally, on September 16, 2014, Subcommittee staff reached out to NASA in order to gain support for facilitating a briefing on the Commercial Crew Transportation Capabilities (CCtCap) contract source selection, as well as the source selection statement. After NASA issued the request for proposals (RFP) for the contract it declined to comment on the procurement so as to not influence the selection. Understanding the sensitive nature of the source selection process, the Committee decided to reserve questions regarding the procurement until after the selection. Similarly, the Committee also withheld queries until after the offerors were briefed on the selection. It is our understanding that at this point all of the offerors have been briefed. Unfortunately, NASA continues to delay providing Congress with information related to this program and the source selection. We are aware that the selection was referred to the Government Accountability Office (GAO) 3 as part of its bid protest process;4 however, this should not preclude NASA providing information to Congress as the statute that governs the protest process states "[a] protective order under this paragraph shall not be considered to authorize the withholding of any document or information from Congress or an executive agency."5 To date, the Committee has not been briefed on the source selection, nor has it received the source selection statement, despite the fact that offerors have been briefed, details were released to the press,6 the GAO is now involved; and NASA has decided to proceed with the contracts.7 Up to this point, NASA has not provided Congress with detailed information related to the CCtCap source selection in almost one year during the "blackout period." We assume the Administration will submit a budget proposal to Congress in the next few months that will include funding for the CCtCap program. Congresses' ability to evaluate this budget request may be challenged by NASA's uncooperative position. We hope that NASA will not expect taxpayers to blindly fund billion-dollar programs absent any information related to the procurement or contract. This Committee has demonstrated a commitment to ensure that American astronauts are once again launched on American rockets from American soil. NASA's refusal to provide necessary updates to Congress may unnecessarily impact these efforts."
Advanced Concepts / Re: EM Drive Developments
« Last post by birchoff on Today at 01:43 PM »
I ... estimate ... the Flight thruster dimensions ...

w-small = 1"
w-big =   2"
height = 3"


I am dizzy with all the tests that Shawyer has conducted and with the different names he gives the tested device.  ...

This is circumstantial and corroborating evidence supporting the conjecture regarding the intentional reluctance of the experimentors to freely share their data.

The reluctance is certainly understandable, for at least three reasons, none of which can be discussed except on an informal basis among disinterested professional friends:

1. A surfeit of professional pride in understanding the obscure physics, combined with the typical disregard paid by professionals to amateur website contributors.

B. A pragmatic need to share without sharing, knowing full well the economic benefits of a vastly superior propulsive method.

iii. A stubborn refusal to realize that nothing is being seen.

Vee. Other reasons, such as keeping the rabble occupied with measuring Faztek thingies, so as to keep them off the streets protesting the forty year lack of accomplishment at NASA at doing what was promised back then; a peaceful future realizing mankind's destiny in the universe at large.

As I mentioned at:

I note that we are spending a lotta time arguing about these dimensions.  The good Doctor asked, rather politely, a hundred or more pages ago, but got only partial dimensional answers.  Since then Paul March decided to go mum. 

Easily answered questions go without answer, which reflects on those who experiment, not on those who try to understand.

I'd like to thank the EagleWorks team for their help and cooperation.  (They should probably set up shop in Awizona; 'twould help their worldview.)

On the plus side, thanks to decent forum moderation, we no longer have to hear from those who disparage everybody's credentials.

Does this mean we have collectively gotten to the point that there is not enough information available to make any conclusions?
Meaning that the flight rate of Falcon 9 might actually not have been limited (recently) by the availability of the payloads or the stages, but by the production rate of the engines. Very interesting.

If the production rate is now at 4 per week and going to 5 soon SpaceX will be pumping out Merlin 1D's at a rate of 250 per year. Enough for 25 flights per year. So any limitation in launch rate due to production rate of Merlin 1D's should be going away fairly soon.

The numbers don't add up to a continuous production rate of 4 per week....
If the crs 4 core was shipped to mcgreggor in say mid july (since it was in Florida for the first week in aug), with the ~80th just-manufactured merlin D on it, that means they have manufactured at most 20 more engines in about 12 weeks, or only about 1.6 a week, not 4.

Now, perhaps they mean that 100 engines have been fully stage-qualified and test-fired, which would be true if the CRS-5 stage and one-other stage (Orbcomm or f9-dev2 perhaps?) have completed McGregor workflow.
In which case, they probably have far more than 100 engines assembled, but not test fired and integrated.
Possibly up to 30 more?
Jim, every point you listed is right, I was perfectly aware of them, and I'm not saying it MUST work, for engineering evaluation I mean doing all the math and check if it can work


considered the benefit of a not thrown away second stage at every mission, I'm wondering if this design could worth  the added cost/complexity you have mentioned


you could always develop an uncrewed version also, to launch small satellites or make ISS cargo mission

just my two cents

Elon Musk is teaching us that nothing is impossible
Well, if that isn't revealing then I don't know what.
Eighty engines have flown already. Another ten are on the booster for CRS-5 slated for early December.
Meaning that the engines for the next flight after that have only just finished production.

It also reveals that 10th F9 flight will be in 2015
Advanced Concepts / Re: EM Drive Developments
« Last post by Rodal on Today at 01:36 PM »
Another device of equivalent preagmatic utility.
Doesn't the pictured device only work in a partial vacuum (thus the glass enclosure) and neither the discussed NASA Eagleworks, Shawyer of Chinese experiments were conducted in such partial vacuum conditions inside glass enclosures?

Advanced Concepts / Re: EM Drive Developments
« Last post by Rodal on Today at 01:31 PM »
It is incorrect to state that only DC fields can produced ionic winds.  I don't know whether such a misunderstanding may come from reading Wikipedia articles.

AC fields can also produce ionic wind in a variety of ways.  For example, the point electrode and ring electrode system is capable of generating electric winds (with velocities of few m/s) for both DC and AC applied voltages.  In the AC regime, ions generated within the corona move in the field and migrate a distance before recombining; the net flow of ions away from the corona creates a time-averaged force that drives the steady flows.  AC coronas can sustain wind velocities of over 1m/s independent of electrode separation in marked contrast to DC coronas.

Another arrangement in which AC fields can produce ionic wind is dielectric barrier discharge actuators.  AC applied across the electrodes through the dielectric produces a variety of electric breakdown phenomena (e.g., corona, streamers, and plasma).  Spark breakdown is prevented by the dielectric barrier. Transient migration of charged species within AC fields also gives rise to steady electric winds.
My two cents.
You are looking too far into the future.
Every gram that can be shaved from a spacecraft is less reaction mass (ie propellant) needed for maneuver.
Some subsystems also are very mass sensitive, one of the strong points of Soyuz is having separate Orbital and Reentry modules, saving a lot on TPS mass.

Obviously technology advances, but I think we are still too far from the "integrated spacecraft" point.
Consider also that Dragon is designed to retain (and reuse) LAS and heatshield (while for example CST-100 eject both).

(Well, I waited too much, Jim put on the table  a ten dollar bill !)
Because the near future potential market is for LEO applications, think about bigelow orbital hotel...

And tell me, which other applications are envisioned in the immediate future for the dragon V2, other than ISS crew turnover?

SpaceX is not building for the immediate future. They need the more general problem of retrieving second stages solved for their future plans. Your suggestion does not advance them in the direction of their long term goals.

Landing on a runway seems a lot safer than propulsively retro rocket;

"Seems" does not a quantifiable term and meaningless in this case.  Both have advantages and disadvantages. 
Pages: [1] 2 3 ... 10 Next