IIRC the master program plan document or whatever it was called explicitly said only 6 ATVs were planned, before the first had even flown. Then that got dropped to 5 later on.There was a gap in the SM to allow a docking tunnel to be added there in the future with only minimal mods. One of a ton of ATV derivatives proposed
Something I never quite understood is why Japan kept building HTVs ?
Quote from: brickmack on 02/28/2018 01:32 amIIRC the master program plan document or whatever it was called explicitly said only 6 ATVs were planned, before the first had even flown. Then that got dropped to 5 later on.There was a gap in the SM to allow a docking tunnel to be added there in the future with only minimal mods. One of a ton of ATV derivatives proposedATV was, from the very beginning, conceived as a technology demonstration program. And it did exactly that. It proved that ESA and its contractors had the expertise to independently develop and fly (cargo) spacecraft. And it is correct that, from the onset, only six ATVs were planned. ESA stuck to that plan simply because, at the time, ISS was expected to be de-orbited in the 2019-2020 timeframe. But events overtook this and ISS was extended, first to 2022, and than to 2024. But based on the original estimated ISS lifetime, the ATV production line had been shut down. So, when it became apparent that ISS would continue beyond 2022 ESA needed something different to barter for their continued presence on the station. NASA pitched an idea, based on ATV, and ESA went for it. You see, development of the Orion ESM fits perfectly as a follow-on to the original technology demonstration program that ATV was.
Quote from: woods170 on 02/28/2018 07:13 amQuote from: brickmack on 02/28/2018 01:32 amIIRC the master program plan document or whatever it was called explicitly said only 6 ATVs were planned, before the first had even flown. Then that got dropped to 5 later on.There was a gap in the SM to allow a docking tunnel to be added there in the future with only minimal mods. One of a ton of ATV derivatives proposedATV was, from the very beginning, conceived as a technology demonstration program. And it did exactly that. It proved that ESA and its contractors had the expertise to independently develop and fly (cargo) spacecraft. And it is correct that, from the onset, only six ATVs were planned. ESA stuck to that plan simply because, at the time, ISS was expected to be de-orbited in the 2019-2020 timeframe. But events overtook this and ISS was extended, first to 2022, and than to 2024. But based on the original estimated ISS lifetime, the ATV production line had been shut down. So, when it became apparent that ISS would continue beyond 2022 ESA needed something different to barter for their continued presence on the station. NASA pitched an idea, based on ATV, and ESA went for it. You see, development of the Orion ESM fits perfectly as a follow-on to the original technology demonstration program that ATV was.ATV also competed as a COTS vehicle in partnership with Boeing as lead and commercial launch provider.