...As a aside what exactly is the liftoff thrust of A64? All sites give 1500 tons but when I sum up vulcain (100 tons) and 4 P120C (4*450 tons, "average thrust" on Avio’s site) it gives closer to 1900 tons, are the P120C burning at a lower thrust at liftoff?
Quote from: TheKutKu on 01/30/2023 09:41 am...As a aside what exactly is the liftoff thrust of A64? All sites give 1500 tons but when I sum up vulcain (100 tons) and 4 P120C (4*450 tons, "average thrust" on Avio’s site) it gives closer to 1900 tons, are the P120C burning at a lower thrust at liftoff?Yes, this can be clearly seen in the P120C static firing tests. After P120C ignition, the thrust level increases for some time. Than it decreases to a lower point untill burnout.I'm very doubtfull about the long term succes of leo comsat constellations. I think that if/when Europe desides to launch one, it will look more like oneweb than starlink.The LEO comsat constellations cause problems for astronomy/ ground based telescopes.And Parabolicarc posted this article: ozone layer report raises fears about expansion of space activitiesShort summary: environmental consequences of reentering satellites are unknown. They could cause the ozone layer to stop healing/ closing.This environmental aspect weight much more heavily in Europe than in the USA.We might end up requiring satellites with multi-decade operational lifetime. This might be enabled by satellite servicing. This would indeed mean much larger satellites (no cubesats).I still view a fleet of Stratobus, Stratospheric pseudo satellites, as viable alternative for leo comsat constellations. For the 202x's Ariane 6, Vega (C/E) and some small/microlaunchers could provide europe with independent acces to space. If Europe decides to develop a reusable launcher, i expect it to have a launch capability simular to SpX Falcon9 or RocketLab Neutron, not BO New Glenn, let alone Starship. Possibly the upperstage could be recovered as well.I'm not aware of a propulsive landing technology in Europe. So Europe can't propulsivly recove a stage. Land a rover on the moon or on Mars. Yes, the sad fact is that Europe is over a dacade behind on SpaceX, BlueOrigin and Rocketlab.Mistakes in the Ariane 6 development mean no-acces to space from H2 2022 to at least H1 2024. And 700mln Euro being waisted on the Ariane 5 to Ariane 6 transition. (Three years hardly any launcher production.) What could have been developed with this funding alternatively. Rocket engine test sites are heavily restricted in test time for noice and other environmental reasons. The same will be the case for stage recover testing.
...No offense, but that is almost never the case. Particularly not in the world of comsats. First those got heavier and heavier, driving the development of more capable launch vehicles (instead of the other way around). But in recent years a reverse trend has emerged: Guess what became less heavy in recent years? That's right: comsats. Tugging along a cr*pload of propellant for GTO-to-GEO is on the way out. Tugging along much lighter solar electric propulsion for GTO-to-GEO is in.The reason Starship has such massive upmass capability is primarily for their own purposes: Starship is being built first-and-foremost to serve the SpaceX endgoal: Mars. Such massive upmass secondly serves to get the rest of the Starlink constellation up in as few launches as possible (economics driven).But other than that there are NO non-SpaceX payloads - existing or in development - that make full use of the massive Starship upmass capability. Heck, even the way less capable Falcon Heavy is struggling to find payloads that make full use of its capabilities. That reality applies to both commercial and DoD/NRO payloads.So, I am not buying your narrative. And that should tell you that I think that Europe does not need its own 150-ton-to-LEO, full reusable launch vehicle. What I do think is that Europe should be working on is a 50-ton-to-LEO full reusable launch vehicle.
...IF starship is successful and launch cost drop dramatically, (not guaranteed but at least that is the plan if starship succeeds), I would expect to see a return to heavier comsats using chemical propulsion to get on station quicker.
I'm very doubtfull about the long term succes of leo comsat constellations. I think that if/when Europe desides to launch one, it will look more like oneweb than starlink.The LEO comsat constellations cause problems for astronomy/ ground based telescopes.And Parabolicarc posted this article: ozone layer report raises fears about expansion of space activitiesShort summary: environmental consequences of reentering satellites are unknown. They could cause the ozone layer to stop healing/ closing.This environmental aspect weight much more heavily in Europe than in the USA.We might end up requiring satellites with multi-decade operational lifetime. This might be enabled by satellite servicing. This would indeed mean much larger satellites (no cubesats).I still view a fleet of Stratobus, Stratospheric pseudo satellites, as viable alternative for leo comsat constellations.
Israël: hopefully have the first Ariane 6 launch by the end of the year, but some risk to that.
A column by Marco Fuchs: thoughts about time and space"I strongly believe in the Rocket Factory – withdrawal is out of the question"No space flight without rockets. Why this is the hour of the microlauncher.20 March 2023. ...Ariane 6, the successor to Ariane 5, is in a crisis, and in my estimation it will be at least another year before the first launch....
...Mr Daniel Neuenschwander is reassigned as Director of Human and Robotic Exploration Programmes (D/HRE) as of 1 July 2023 and renewed for four years as of 1 July 2024. He will be based at the European Astronaut Centre (EAC) in Cologne....Mr Toni Tolker-Nielsen is nominated as acting Director of Space Transportation as of 1 July 2023....
Andre-Hubert Roussel will step down as CEO of ArianeGroup- a French aerospace joint venture between Airbus and Safran – French newspaper La Tribune reported on the 30th of March. ...The current CEO of ArianeGroup will be replaced by Martin Sion, the president of Safran Electronics and Defence.
Would not a wider single first stage be more efficient than the six engines 3 booster reusable final evolution of a Ariane 6 ?
From comments during today's JUICE launch: 28 Ariane 6 launches sold so far, of which 18 are for Kuiper.
Quote from: woods170 on 04/14/2023 12:30 pmFrom comments during today's JUICE launch: 28 Ariane 6 launches sold so far, of which 18 are for Kuiper.Not all that impressive actually. It means that besides Kuiper, Arianespace has managed to sell only 10 Ariane 6 launches to other customers so far.
Quote from: woods170 on 04/14/2023 12:34 pmQuote from: woods170 on 04/14/2023 12:30 pmFrom comments during today's JUICE launch: 28 Ariane 6 launches sold so far, of which 18 are for Kuiper.Not all that impressive actually. It means that besides Kuiper, Arianespace has managed to sell only 10 Ariane 6 launches to other customers so far.It looks more like 28 *planned* without kuiper looking at various contract.When did they say the part about "18 for kuiper"? I didn't hear that at around the 1:02:00 mark
Wow. The Ariane 6 is proving to be a disaster for European space policy. Hard to say it is otherwise at this point.
EU turns to Elon Musk to replace stalled French rocketBrussels is looking to negotiate a ‘security agreement’ with US to keep its space program running.BY JOSHUA POSANER AND LAURENS CERULUSAPRIL 17, 2023 5:40 PM CETThe European Commission wants to cut deals with private American space companies like Elon Musk's SpaceX to launch cutting-edge European navigation satellites due to continued delays to Europe's next generation Ariane rocket system.