Exoscientist

Have you tested this against existing launchers? Bob Clark

Good point. Also is that a real disk visible in that blown up photo or just fuzziness of the blown up image? Bob Clark

Anybody with image processing knowledge to tease out more detail of that image of the base of the F9R? Much discussed whether it will have the full 9 engines or just three on this test vehicle. Bob Clark

That hovering question has been much discussed on Nasaspaceflight.com. Even the current F9 has too much thrust just firing a single throttled down Merlin to hover. Apparently SpaceX will accomplish the landing doing short bursts of the engine. Bob Clark

The problem with that argument is National Security satellites are so hugely expensive, frequently in the billion dollar range. NASA science satellites are also frequently expensive, such as the billion dollar Curiosity mission. Commercial satellites in contrast are frequently in the $100 to $200 million dollar range. Imagine then the improvement to the satellite operators bottom line if they could reduce their launch costs from say $50 million to $5 million. Just the current lowered prices of SpaceX without reusability led some satellite operators to be highly positive towards the change: SES and SpaceX: Shaking the Industry to its Roots. By Veronica Magan | January 21, 2014 | Europe, Launch, North America, Publications, Regional, Telecom, Via Satellite Quote: “This launch, in my opinion, is probably the most important launch in the commercial arena, certainly since 1996, no doubt about it,†Halliwell said. “There are detractors, who are hoping for a failure, but the majority of the commercial satellite world is waiting for a success because it really opens a whole bunch of opportunities.†... The successful SES 8 launch is likely to mark a new era for the satellite industry. “The entry of SpaceX into the commercial market is a game changer, it’s going to really shake the industry to its roots,†Halliwell said. “We think this is the way to go forward for the future.†http://www.satellitetoday.com/publications/2014/01/21/ses-ans-spacex-shaking-the-industry-to-its-roots/ Bob Clark

Not to be derailed into politics but that's actually a conservative viewpoint, at least as such terms are used in the U.S. Bob Clark

The Raptor could still be used on a Falcon 9 sized vehicle. You would simply use fewer engines. Probably also call it something else then. Bob Clark

After Antares test launch, Orbital aims for space station. BY STEPHEN CLARK SPACEFLIGHT NOW Posted: April 26, 2013 http://spaceflightnow.com/antares/demo/130426cygnus/ A medium class launcher by the usual fully government-financed approach would cost in the multi-billions of dollars range. For instance the Ariane 6 is expected to cost in the range of $5 billion. And that's just the initial estimate. Quite likely just as with NASA fully government-financed projects, there will be significant cost overruns here as well. That both SpaceX and Orbital Sciences were each able to develop their launchers at a 90% cost savings by following the commercial space approach is important. It means any industrialized nation could afford to develop their own independent orbital launch system via commercial space. There would not need to be this constant wrangling within the ESA among France and Germany and Italy about which approach to take. They could each decide to take their own approach. Which space agency will be next to make the great leap to commercial space? Bob Clark

By Deborah Byrd in BLOGS | EARTH | HUMAN WORLD on Sep 28, 2013 U.S. sees another bright fireball on September 27. http://earthsky.org/earth/u-s-midwest-sees-another-bright-fireball Bob Clark

Opening ourselves up to alternative ways of doing things may allow us to return to the Moon: Saturday, September 28, 2013 Free your mind, and the rest will follow. http://exoscientist.blogspot.com/2013/09/free-your-mind-and-rest-will-follow.html Bob Clark

Congrats to Orbital Sciences and NASA's Commercial Orbital Transportation Services(COTS) program! Bob Clark

After Chernobyl and Fukushima, it's not strange. Bob Clark

Nice video but I don't think nuclear rockets launched from Earth would have been acceptable. Perhaps if we had space stations on the Moon such vehicles could be launched from there. Bob Clark

Newbie here just learning to use the forum. I teach math at an east coast U.S. university. How do I change my profile and signature? I get an error message that it's not authorized. Bob Clark

I was trying to get a lower roundtrip delta-V for lunar missions by flying directly to the lunar surface rather than going first into lunar orbit then descending, the "direct descent" mode. Here's a list of delta-V's of the Earth/Moon system: Delta-V budget. Earth–Moon space. http://en.wikipedia.org/wiki/Delta-v_budget#Earth.E2.80.93Moon_space If you add up the delta-V's from LEO to LLO, 4,040 m/s, then to the lunar surface, 1,870 m/s, then back to LEO, 2,740 m/s, you get 8,650 m/s, with aerobraking on the return. I wanted to reduce the 4,040 m/s + 1,870 m/s = 5,910 m/s for the trip to the Moon. The idea was to do a trans lunar injection at 3,150 m/s towards the Moon then cancel out the speed the vehicle picks up by the Moons gravity. This would be the escape velocity for the Moon at 2,400 m/s. Then the total would be 5,550 m/s. This is a saving of 360 m/s. This brings the roundtrip delta-V down to 8,290 m/s. I had a question though if the relative velocity of the Moon around the Earth might add to this amount. But the book The Rocket Company, a fictional account of the private development of a reusable launch vehicle written by actual rocket engineers, gives the same amount for the "direct descent" delta-V to the Moon 18,200 feet/sec, 5,550 m/s: The Rocket Company. http://books.google.com/books?id=ku3sBbICJGwC&pg=PA174&lpg=PA174&dq=%22direct+descent%22+Moon+delta-V&source=bl&ots=V0ShEuXLAv&sig=QIpkcV9Gtu-rYMOYJpLOmWwsy54&hl=en#v=onepage&q=%22direct%20descent%22%20Moon%20delta-V&f=false Another approach would be to find the Hohmann transfer burn to take it from LEO to the distance of the Moon's orbit but don't add on the burn to circularize the orbit. Then add on the value of the Moon's escape velocity. I'm looking at that now. Here's another clue. This NASA report from 1970 gives the delta-V for direct descent but it gives it dependent on the specific orbital energy, called the vis viva energy, of the craft when it begins the descent burn: SITE ACCESSIBILITY AND CHARACTERISTIC VELOCITY REQUIREMENTS FOR DIRECT-DESCENT LUNAR LANDINGS. http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700023906_1970023906.pdf The problem is I couldn't connect the specific orbital energy it was citing to a delta-V you would apply at LEO to get to that point. How do you get that? Bob Clark

Thanks for the info. Bob Clark

Thanks for those refs. I\'ll give them a read. Bob Clark

Robert Zubrin has proposed lower cost missions using the new Falcon Heavy rocket: MAY 16, 2011 Robert Zubrin\'s Proposes using three Space Falcon Heavy Launches to send two people to Mars by 2016. http://nextbigfuture.com/2011/05/robert-zubrins-proposes-using-three.html MAY 17, 2011 Zubrin provides more explanation of his Space Falcon Heavy Mars Plan. http://nextbigfuture.com/2011/05/zubrin-provides-more-explanation-of-his.html Bob Clark

That\'s a good plan. That notation with the power as a superscript between the 'sin' and the '(x)' does indeed mean raise the sine function to that power. On a calculator you could enter like this: (sin(x))^2. To get an idea of what the answer to your problem is try plugging large numbers on your calculator into: (sin(x))^2/(x^2+1) Bob Clark

Hello, just joined the forum. How do you get the mathematical formulas into your posts? Bob Clark

Hello, newbie here. I have some spacecraft proposals that I want to create simulations for that I discuss here: The Coming SSTO\'s. http://exoscientist.blogspot.com/2012/05/coming-sstos.html How do you use the kerbal program to simulate a space launch? Also does kerbal have accurate trajectory calculators where you can get a good idea about how much payload your rocket can get to orbit? Thank You, Bob Clark