I knew that Orbital ATK would think about launching more Cygnus spacecrafts atop Atlas V; it was a matter of time.After OA-7, Antares would have launched seven times plus the Orb-3 failure in 2014. Compared to 73 successes out of the previous 74 Atlas V flights, I think one of the reasons that the latter would be used for Cygnus is because of its higher success rate.
Why? What's going on with Antares?Is it more cost-effective for OA to supplement Cygnus/Antares launches with Cygnus/Atlas V launches?Is an outside vendor's "ride" less expensive than purchasing their own rocket?
So you draw the conclusion that Antares launcher offering will end in the not to distant future.
It's NASA that prefers launching Cygnus on Atlas V above Antares, because of the higher payload capability.
OATK stil has to launch OA-8 to OA-11 right for COTS1 extended?. OA-8 will launch on Antares and I expect at least one more. Some of them will launch on Atlas V.
Secondly, both Atlas V and Antares use RD-18x engines, not so much difference there.
I agree with the launch cost spiraling out of control. Does someone know how many tanks OATK has laying around? I think that OATK will launch those; Or Yuzhnoye buys them back for Cyclone-M.
So is the conclusion that Antares 200 will use up the existing amount of tanks. Antares 300 won't be developed, instead it will be replaced by a NGL version.
What is comparable to Antares?: ...
Quote from: Space Ghost 1962 on 10/26/2017 08:32 pmNone past November's, that I'm aware of launch contracts for.Three through 2019, including OA-8. Then six more 2019-2024, though some or all of those could go on Atlas 5.https://spaceflightnow.com/2017/10/10/wallops-launch-base-receives-final-hardware-delivery-for-next-cygnus-mission/Orbital ATK ordered eight RD-181 engines in 2015. That's enough for four Antares launches, including one that has already flown. The company has an option to buy as many as 30 engines. - Ed Kyle
None past November's, that I'm aware of launch contracts for.
“The first mission type is a pressurized cargo mission on Antares, very similar to what we’re flying on OA-8 to OA-11,” DeMauro said in a July 11 interview. “Those will have a little bit more cargo capacity, but it’s an Antares-based mission.”NASA has authorized the first of the six Cygnus flights planned from 2019 through 2014. Named OA-12, that mission will launch on an Antares booster from Wallops Island with pressurized cargo.“We have six missions that have been contracted for on CRS-2,” said Frank Culbertson, a former astronaut and president of Orbital ATK’s space systems group. “The first one has been given a go-ahead for activity, so we are doing long-lead purchasing, beginning the process to … start building the structure. That one should launch in, we hope, 2019.”
DeMauro said there are no plans to return to the Atlas 5 for the foreseeable future, as the company completes its original Commercial Resupply Services (CRS) contract and starts a follow-on award called CRS-2. “Our baseline plan is to continue to fly Cygnus on Antares,” he said. “We are ready to respond to our customer’s needs, if they should require something different, but for all of the rest of CRS-1 and so far for the CRS-2 missions we’re planning to do them on Antares.”After this launch, Orbital ATK has three missions remaining on its CRS contract, OA-9, 10 and 11. No firm launch dates have been set, but DeMauro said OA-9 could launch as soon as the first quarter of 2018. OA-10 would then likely follow in the fall of 2018 and OA-11 in early 2019. DeMauro said later that NASA has ordered two Cygnus missions so far under its CRS-2 contract, OA-12 and 13.
Frank DeMauro said that OA's plan is to continue flying Cygnus on Antares, and that they currently have orders out to OA-13.QuoteDeMauro said there are no plans to return to the Atlas 5 for the foreseeable future, as the company completes its original Commercial Resupply Services (CRS) contract and starts a follow-on award called CRS-2. “Our baseline plan is to continue to fly Cygnus on Antares,” he said. “We are ready to respond to our customer’s needs, if they should require something different, but for all of the rest of CRS-1 and so far for the CRS-2 missions we’re planning to do them on Antares.”After this launch, Orbital ATK has three missions remaining on its CRS contract, OA-9, 10 and 11. No firm launch dates have been set, but DeMauro said OA-9 could launch as soon as the first quarter of 2018. OA-10 would then likely follow in the fall of 2018 and OA-11 in early 2019. DeMauro said later that NASA has ordered two Cygnus missions so far under its CRS-2 contract, OA-12 and 13.http://spacenews.com/orbital-atk-looks-to-antares-to-handle-cargo-resupply-missions/
They snuck another third stage option in at some point. Northrop Grumman's factsheet shows the options of the Star 48, Orbit Adjust Module (used to be called bi-propellant third stage), and now also shows an Orion 38 motor.
Speaking of which, can anyone help decipher the Antares 23x+ characteristic energy versus payload chart? Where would GTO be, for example? - Ed Kyle
Quote from: edkyle99 on 06/12/2018 09:01 pmSpeaking of which, can anyone help decipher the Antares 23x+ characteristic energy versus payload chart? Where would GTO be, for example? - Ed KyleI've never done this for a bound orbit, but using the definition that c3 = 2x specific orbital energy, we getc3 = 2 * (v^2/2- u/r)For GTO, v = 1596 m/s at the top of the orbit (if a 250 km perigee), r = 42157 km, and u for Earth is 3.986e14, then plugging in we get -16.4 km^2/sec^2.EDIT: spelling