Hermès or the missed opportunity for Europeans to be autonomous in human space flights

In our articles, when it comes to dealing with subjects related to European manned flights, Futura often refers to the Hermès space plane project to highlight the missed opportunity for Europeans to be autonomous today in matter manned flights. Indeed, since this abandonment, theESA has made the choice of international cooperation – and therefore to barter the flights of its astronauts – rather than developing its own manned space transport infrastructure.

That said, the Hermès program obviously cannot be reduced to this single failed ambition, which can be explained in particular by a lack of political will. Hermès is also a story, spanning more than twenty years, which, although it did not allow this small space shuttle to fly, has nonetheless enabled Europe to acquire many technologies necessary for manned flights. On this point, the heritage of Hermès is substantial.

To get a more precise idea of ​​the history of the Hermès program, from the first studies to its abandonment, we took advantage of the bookstore release of a test on the Hermès program to meet its author, François Leproux. This engineer in space mechanisms, president of the 3AF Grand Est group and specialist in the space sector, reviewed the history of this space shuttle, its motivations and the reasons for its failure as well as its technological heritage. A fascinating interview.

Futura: what did Europe lack to equip itself with a manned space transport system?

François Leproux: If a lack of political will was undeniably lacking in Hermès, from a technical point of view, the concept was also very ambitious. In November 1992, when it was abandoned, it turned out to be technically and financially unfeasible under the conditions originally envisaged. There were many technological leaps to be taken. Arriving in the field of manned space transport with an airplane was very ambitious, a bit as if Europe had wanted to go from the steam train to the TGV without going through the capsule stage as the Russians, the Americans have done so well. and today, China and SpaceX.

What Hermès also lacked is that, unlike the Ariane program which won unanimous support around it due to the fact that it had to give Europe autonomous access to space, this project was not not as unifying as Ariane. A few countries were not convinced of the usefulness of a space plane.

For Italy and Germany, Hermès and human space flights were not justified. The program was seen as a technological project with little operational value, like the Concorde.

There was also some industrial inconsistency. The division of tasks between ESA, national agencies and manufacturers was not completely clear-cut, satisfactory. The basis of the program was too fragile.

Industrial inconsistency? That is to say ?

François Leproux: You should know that originally Hermès is a French program. When it came to “Europeanising” it, the French government had already chosen its own manufacturers to carry it out. Dassault-Breguet and Aérospatiale were in charge of most of the development of the aircraft. A situation that was frowned upon by its European partners. France has also been criticized for using ESA to finance its own space ambitions. That said, the creation of EuroHermèspace was an interesting attempt to bring together French, German and Italian industrialists within a single structure. Dissolved with the abandonment of Hermès, it has the merit of having laid the foundations of Arianegroup.

In 1992, was not the low orbit context the one envisaged when the decision to develop Hermès was made?

François Leproux: Yes. When the decision was taken to abandon Hermès, the context had changed enormously since the end of the 1970s. The LEO-hub imagined a few years earlier and which could justify an almost permanent human presence in orbit bass was no longer considered for decades. In a way, those who had imagined theemergence from an economy of space in low orbit with an extended use to a wide range of services were too far ahead of time! The LEO-Hub is becoming a reality favored by the arrival of actors from Newspace.

Haven’t the broken promises of the space shuttle been a drag on Hermès?

François Leproux: This is an essential point. Initially, Hermès was imagined to serve a small station in low orbit and bring back to Earth materials manufactured in orbit. For the Europeans, it was not conceivable to arrive with a capsule while the Americans and the Russians were developing a shuttle. At the time, the concept of the inhabited capsule seemed outdated. When, after only a few operational flights, the Nasa realized that his spaceship was dangerous and complicated to use so that one could not go into space as easily as one takes the plane, the Hermès project was called into question.

The mass of Hermes?

François Leproux: It’s been a big problem throughout development. Hermès’ first sizing studies were based on the expected performance ofAriane 5 with a capacity to launch 15 tons into low orbit. Over the course of development, the mass of the space plane got heavier to finish at 17 tons. After the loss of the shuttle Challenger and his crew, it was decided to add ejection seats. Hermès has also been equipped with a separable module, a cone mooring and batteries, which made the aircraft heavier. The latest Hermès concept could no longer be launched by Ariane 5!

Hermès was quite different from the American shuttle. We used to say that it fixed many “flaws” of the American shuttle. So we can be surprised at the choice of NASA for the shuttle as it was designed?

François Leproux: Indeed. The fundamental difference between Hermès and the space shuttle was its integration with its launcher. The European spaceplane was located above the Ariane 5 launcher and not against, as was the case with the shuttle. This had the main advantage that Hermes was protected from falling debris (mousse insulation, ice for example) and that in the event of an explosion of the launcher, the crew was located 20 meters away, which could give them additional chances of survival. In addition, the American shuttle had the other drawback that it had to carry a significant crew and have the capacity to transport US Army spacecraft, or even bring them back to Earth. Two mutually damaging requirements. In the case of Hermès, the payload transport function was devolved to a classic Ariane 5.

NASA was aware that its choice was not optimal for the safety of the crews. It had to deal with the requirements of the military who wanted to be able to launch the shuttle from Vandenberg, and recover very large payloads in orbit, hence the large volume from the hold of the Shuttle. The size of the cargo bay forced engineers to equip the Shuttle with large Delta wings instead of the initially imagined right wing, resulting in a less safe vehicle than expected.

In terms of safety, Hermès was aiming for more than 99.999% (the reliability of the Ariane 5 launcher being 99%), the 0.001 being covered with a crew ejection system, which the Challenger crew lacked. died not in the shuttle explosion but in its crash in the ocean.

That said, despite the abandonment of Hermès, its advances have directly or indirectly benefited all space programs.

François Leproux: Indeed. But not only in the space sector. We can cite pell-mell the software of modelization in hypersonics, operating safety architectures, third generation thermal materials, semi-load-bearing bodies for example. Thus, from the technological bricks of Hermès, programs were born such as ATV, ARD and Space Rider. The IXV, the demonstrator atmospheric re-entry, is the program that has benefited the most from the developments initiated for Hermès (thermal materials, aerodynamic design in particular).

Regarding Hermès design, did Dassault’s choices turn out to be excellent?

François Leproux: Yes. Initially envisioned as an “American space shuttle”, its appearance has gradually shifted towards that of a delta-wing aircraft without tail vertical, this one being replaced by two winglets at the end of the wing. A configuration so well optimized that NASA recognized that this concept imagined by Dassault, of a very thin wing with winglets at its ends was very relevant. Moreover, this design is taken up by many space aircraft projects such as the Dream Chaser. This configuration was notably tested in flight by the X-38 as part of the CRV program which was to give rise to a rescue vehicle for the crews of theISS.

What other areas have benefited from Hermès?

François Leproux: We talk less about it, but Hermès has been an accelerator in the development of many technologies that are not in the space sector. As an example, we can cite the Catia software from Dassault. Initially developed for the Rafale aircraft program, Hermès has undoubtedly accelerated its development. The development of fuel cells was also accelerated with Hermès, as were the electric flight controls which were also being developed in parallel for the Airbus A320. Hermès’ in-orbit piloting and in-orbit docking algorithms were used by ATV and are still used for satellites. If, strictly speaking, Hermès did not give birth to new technologies, it should be noted that the program could have favored the creation of a sector in Europe in the field of cockpit flat screens.

A Hermès tomorrow?

François Leproux: I am fairly convinced that the European Space Agency will decide to provide Europe with access fall to space for its astronauts. The very strong dissensions of the 1980s between France, Germany and Italy are less evident today. Italy is a pretty strong supporter and in Germany there are fewer objections than before.

Josef Aschbacher, the new Director General of ESA, promotes human space flight a lot. All the lights are green, especially with the heavy version ofAriane 6, the Europeans have a launcher whose capacities will allow it to launch a manned vehicle which will certainly be a capsule. In addition, France, which took the 1^er January the presidency of the European Union could speed things up in view of the next ESA ministerial conference scheduled for the end of 2022.