| Which will be the future launcher systems for Europe? | | | | Liquid Fly-Back Boosters (LFBBs) or Reusable First |
| To answer this question ESA started in 2004 the | | | | Stage (RFS). As the Russians explore the capabilities |
| Future Launcher Preparatory Program (or FLPP). But | | | | of Fly-Back Boosters since several years, a |
| let us first look at the current situation. | | | | cooperation between Europe and Russia is considered |
| Currently ESA has access to space through the | | | | from the start on. |
| Ariane-5 launcher, operated by its commercial offset | | | | As these designs, mainly the Fly-Back Boosters, are |
| Arianespace. Developed as a cheaper and more | | | | somewhat conventional, the cost reduction is not for |
| powerful successor of the very successful launcher | | | | sure. In contrast, the more complex reusable |
| family Ariane-4, the Ariane-5 is available in three | | | | technology is still a major barrier. That's why ESA will |
| models. The generic version GS, the heavy-lift model | | | | also investigate and test technologies to reduce this |
| ECA and a modified vehicle for transporting the ISS | | | | complexity. For example there are already structures |
| supply craft ATV, called Ariane-5 ES-ATV. | | | | in evaluation and testing with embedded fiber-optic |
| Through the alliance, called Starsem, of Arianespace, | | | | health monitoring systems. |
| EADS, and Russian partners, ESA can and does also | | | | The most advanced concepts are certainly fully |
| use the Soyuz launchers, especially for interplanetary | | | | reusable Two Stage to Orbit (TSTO) concepts. |
| probes. Currently, the Kourou spaceport gets an | | | | Especially for this kind of launchers, as also for a |
| additional launch pad for the Soyuz rocket, so in future | | | | Reusable First Stage for a semi-reusable concept, |
| it will possible to launch the Soyuz from the | | | | investigation in high performance reusable engines are |
| equator-near Kourou with an increased payload. | | | | seen as a key objective. |
| For smaller payloads ESA develops the Vega | | | | Up to today, only the Space Shuttle and the Energia |
| launcher, consisting of three solid propellant stages and | | | | Buran spacecrafts used reusable engines. Both are |
| one liquid propellant stage. The solid rocket engines are | | | | seen as robust but also as technically demanding and |
| based on the Ariane-5 booster engines. It is planned to | | | | relatively expensive. |
| first-launch the Vega in 2008. | | | | If SpaceX with its Merlin engine, which also should be |
| Recently ESA announced a cooperation with the | | | | reusable, can achieve a successful complexity and |
| Russian Space Agency to build a new spacecraft | | | | cost reduction, time will still have to tell. An analysis of |
| together. As this craft needs a new launcher or at | | | | the possible cost reductions is underway at the Space |
| least a modified launcher, ESA could also use that | | | | Fellowship Forum. The potential cost reduction is surely |
| launcher for future payloads. The rockets currently in | | | | the highest but the development costs will also be the |
| consideration are a modified Soyuz launcher, called | | | | highest. |
| Soyuz-3, a further improved Ariane, or another | | | | Another key objective would be the development (and |
| launcher currently in development, the Angara-3. | | | | maturing) of light-weight reusable stage structures with |
| These launchers will give Europe space access for | | | | cryogenic propellant tanks. Also the second stage |
| the next several years. As the private launcher | | | | would need a reentry system, which would add |
| business is yet unclear, Europe will need a new | | | | structural mass. Additionally reentry systems showed |
| launcher family around 2015 to 2020. | | | | to be complex and very labor-intensive for reuse. |
| The FLPP calls for a future launcher to be operational | | | | Structural mass and additional operational costs for |
| around 2020. Currently the first studies are conducted. | | | | inspection and re-qualification of the system after a |
| Now we will take a look at the potential launchers, | | | | launch are the main difficulties to handle with reusable |
| reusable and expendable both. | | | | systems, as compared to an expendable vehicle. |
| One important condition for the whole program is the | | | | As the reusability adds structural mass, e.g. increasing |
| use of matured technologies and concepts. Designs | | | | the structural and engine robustness for withstanding |
| like Single Stage to Orbit (SSTO) vehicles or | | | | several launches or adding health monitoring systems, |
| air-breathing propulsion systems like scramjets are not | | | | it's necessary to focus on materials and systems |
| considered because they are not yet proven and | | | | science. Inspection and particularly re-qualification of the |
| sufficiently developed. | | | | hardware is an expensive area as this work is very |
| The most conservative concepts are expendable | | | | labor-intensive. |
| launchers. Aside from a payload increase, they would | | | | Also new procedures are necessary to be developed. |
| incorporate better and especially cheaper | | | | How much of damage to a certain part is tolerable |
| manufacturing and components like low cost engines. | | | | before it will be necessary to replace it? In aviation we |
| But as the launchers would be rather conventional, the | | | | have this expertise today, we can predict for example |
| launch costs would be not very different from today's. | | | | how a small crack will develop and when it's |
| If that would be (on the background of a potential | | | | necessary to replace or repair it. In the aerospace |
| emerging private rocket market) enough to compete | | | | sector we nearly have no such experience yet. |
| with others, that is likely to be a question. The | | | | The clear advantage if all these challenges are |
| advantages clearly would be no dependancies on new | | | | mastered is a low-cost high-performance launcher |
| breakthrough technologies and a manageable budget. | | | | system which will strengthen Europe's future role in |
| On the other side, reusable concepts are investigated. | | | | spaceflight. |
| The first idea are semi-reusable rockets with so called | | | | |