Rmf wrote:thanks for nothing that is. rs-25 were man-rated and that increased costs much more then usual , also used older technology. this is something new and well thought out.Big_Gazza wrote:Rmf wrote:Big_Gazza wrote:Project Canada wrote:U.S. space firm’s success may threaten Russian satellites
The daily newspaper Vzglyad reports that U.S. company SpaceX's success in bringing back to Earth a unit from the Falcon-9 rocket in functioning condition is something really unimaginable. Now the delivery of cargo to near-earth orbit will be at least 10 times cheaper, writes the publication. Does this mean that the Russian Proton and Soyuz satellites will be left without a job?
Experiments on returning the first unit of the Falcon-9 had been carried out since 2010. Only the eighth attempt, conducted on Dec. 21, 2015, was absolutely successful.
The cost of the Falcon-9 launch is currently estimated at about $60 million. The unit returned costs $54 million. SpaceX will therefore lose only $6 million on the Falcon-9 if the unit is able to land by itself for further use.
This could lead to a real revolution in the world space market since the delivery cost of one kilogram of cargo onto the Earth's orbit could fall to $1,100, which on average is 20 times less than on other one-time carriers.
This would leave the Proton, Soyuz, Arian and Atlas satellites out of work, if it were not for one "but." Despite its variety, the Falcon-9 cannot replace, for example, the Proton, since the load-bearing capacity of the Russian carrier is 10 tons more.
However, if the matter involved a large space apparatus weighing 20 tons, two Falcon-9s could deliver a 26-ton object into orbit at a cost of $12 million. One Proton can deliver a 23-ton object for $100-120 million. Therefore, using two Falcon-9s is more advantageous than one Proton, writes Vzglyad.
Someone is channelling Musks propaganda as this is the usual hyper-optimistic fan-boi garbage. It remains to be seen if a pre-flown F9 can be reused with anything like the reliability of a brand new unit fresh off the assembly line. Given the experience with operating "reuseable" shuttles (which in reality were "refurbishable" shuttles requiring huge expenses between launches) I personally doubt that recovery of F9 stage will change the dynamics in a significant way.
One question that is ignored is this - how many satellite owners will be willing to risk their expensive payloads worth several $100M on a USED launcher? Isn't it better business sense to go for superior reliability and plug for the new item? Launcher costs are a small part of a payloads cost in any event.
Another factor that is regularly ignored is that flying back the booster is only achieved by accepting a huge penalty in weight delivered to orbit. The core stage needs enough fuel to reverse its course, fly back to its pad, and then control its descent. This F9 flight delivered a small payload of only 2.2T. That's a large rocket for such a small payload. The idea that "two Falcon-9s could deliver a 26-ton object into orbit at a cost of $12 million" is simply absurd. There is NO WAY that an F9 with a recoverable 1st stage can lift 13T to LEO.
Reuseability is a good idea, but I think Musk is barking up the wrong tree on this one. A large fly-back booster is the better idea as it leverages off conventional aircraft technologies and established maintenance knowledge base of commercial and heavy military aircraft. Design it with modular propulsion plant so that engines can be changed out after each flight and returned to factory for de-coking and cleanup, retest and recertification, while the flyback vehicle is fitted with another propulsion module and reflown.
In any case, only time will tell. The idea that Musk and his F9 will threaten Russia's space industry is simply laughable scare-mongering.
why? shuttle rs-25 engines were refurbished and reused with 100% reliability (better then soyuz) without major problems ,and they are much bigger and older ! so your story is trash.
usa private space has got 1 up on russians thats for sure...
falcon 9 is bit oversized and redundancy is intristic , it uses concept of many engines but with very high thrust to weight ratio (better then famed nk-33), and when launches with 80% full load or lower , it uses spared fuel for landing first stage and its reuse.
if some engine stops working other compensate with 110% power and you still have successful mission but without reusable stage.
so your empty jelaous post is jus that . i warned something must change in communist style bueracracies in russian space agency but every rusophyle apologyst was talking how thats not the case.
Shuttle RS-25s were practically rebuilt after every flight at great expense - that's part of the reason why it cost ~$1B to launch a shuttle. In this instance, reuseability failed comprehensively to deliver on its promise of cheaper access to space.
You are comparing SpaceX Merlin engine to NK-33s??? Merlin are low-tech gas-generator engines while NK-33 is a closed-cycle master-piece. You are correct that Merlins have a higher power-to-weight ration, but thats because it is simpler and inefficient and dumps energy overboard via its turbine exhaust while the NK-33 wastes nothing. Thats why the NK-33 specific impulse (the TRUE measure of an engines efficiency) is 297 sec at sea level, while the poor little Merlin slouches along at 282... (at vacuum its 331 vs 311).
I like how you point out that "if some engine stops working".... Tell me the last time a Soyuz or Proton main engine (not vernier) "stopped working"...
Take a look at the recovered F9 core - its engine bay and lower section is scorched from the heat of its vertical descent (the airflow carries the heat up and around the core rather than down and away as it does during ascent) and if anyone really believes that this recovered stage can simply be wiped down, refuelled and relaunched is quite frankly deluding themselves. At best, the engine bay will need to be dismantled. thermal insulation replaced, and heat-affected metallic components will need to be replaced (consider what an under-strength strut did to the previous F9 flight, now imagine the effect of heat-weakened components in the engine bay which carry the full engine thrust force). They will likely be able to be salvaged and put under heat treatment to return them to the proper temper, but it still adds to the refurb workscope.
"rusophyle apologyst"???? What the fuck are you smoking? I've said NOTHING that isn't properly considered and defensible. Maybe SpaceX have all the answers and can make a real go out of re-use of returned hardware, but its VERY POSSIBLE that like the shuttle before, the F9 reuseability promises will remain undelivered. Again, only time will tell.
wrong , its different concept , merlin d uses- lower chamber pressure and simpler gas generator, safer direct injection instead of showerplate ,and thus lighter ,cheaper ,and safer ,+ reusable engine because its componenets are not stressed mechanicaly as other engines.
RD-180 26,700 kPa 338
NK-33 14,500 kPa 331
Merlin 1D 9,700 kPa 311
their ""loss"" of only less then 10% ISP for all that gain in other areas is actually impressive!!
Wrong again ,its core stage on return is empty of fuel so it uses only 1 of 9 engines to land. ahahahaha...
and even that 1 is refurbished withour problem you dont need much thrust for empty core stage and youre going down not lifting anyway ,its black from coal dirt deposit and its nothing.
but continue russophyle apologyst....
There you go with your stupid "russophyle apologyst" crap. I don't even mention Russia, you sign off with a Russian flag, yet I'M the "russophyle apologyst"?
ISP is king, regardless of your assertions, and for a given set of propellants, ISP is proportional to chamber pressure. Reducing chamber pressure to increase reliability to achieve man-rating is perfectly fine, but it sacrifices performance, and the alternative technique is to build heavier but more robust engines to not only handle the high pressures, but can also withstand multiple full-duration firings. SpaceX adopts the former, while Energomash adopts the later. Which is the better path is open for debate, but I prefer the Energomash approach, especially as their products are staged combustion, and RD-series engines, once lit, go like blazes and don't quit.
Ask yourself - if Musk/SpaceX concept of using a large number of smaller simpler engines is such a winner, why does ULA and the US Military still insist in using RD-180s (despite the political issues), and why do so many in the US want to exercise their negotiated rights to start manufacture in US under license? Why does the Atlas use a single large chamber engine per core? Why do Ariane 5 core use a single engine?
Musk & Space X also claim their engine config has been developed for using a single unit as a return engine, but this isn't overly convincing. Design specification for a low thrust return engine burning for extended periods are very different from a main ascent engine, and trying to do the same job with a single design places too many design constraints on the engines main job of getting to altitude. The Merlin cannot be throttled to very low thrust levels and this mandates a landing trajectory at a high decent rate and a sudden deceleration just prior to touchdown. Its a finicky maneuver and difficult in practice. A much better config would be use of 3-4 RD-180 class engines with a dedicated centreline descent engine optimized for low thrust and capable of wide throttle operation. Bring the stage down at a more leisurely and controlled pace, and have the ability to hover precisely and stabilize prior to committing to the touchdown. SpaceX didn't do this, because they were ideologically wedded to the idea of 100% in-house hardware and lacked the tech for world-class high performance engines, so they had to cobble together a reuseable scheme based on what they could build and then make it work however well they can.
Face facts - the Merlin is a poor-mans engine, and Musk has chosen this approach simply because he lacks the IP for better technology (and doesn't want to pay to buy them). SpaceX hypes their "cheaper & simpler" engine design but the rationale for clustering large numbers of combustion chambers is the same today as when Korolev was forced to cluster 30x NK15s on the N1 1st stage due to lack of availability of a suitable large chamber engine. Musk might emphasis the advantages of an "engine out" capability, but simply using a large number of engines increases the chance of a single unit failure, so I don't see any real advantage, especially when RD-series engine reliability is taken into account.
Edit: I should add however that I do like the Merlin engine for using high-pressure fuel from the turbopump to supply hydraulic power to engine gimbal mechanism. The advantages are that a heavy HPU and fluid reservoir is not required, and it eliminates any risk of losing hydraulic pressure due to a shortage of fluid.