The European Space Agency is developing an observatory that would settle questions about the sun from a unique location: inside the orbit of Mercury. The Solar Observatory, or SOLO, would perform heretofore unprecedented measurements of the heliosphere and solar wind as well as magnetic storms and coronal mass ejections, not easily available from our neck of the solar system due to the sun’s 25 day sidereal rotation and small obliquity with respect to the plane of earth’s orbit:

The spacecraft will provide remarkable views of the Sun’s polar regions and farside. Its elliptical orbit will be tuned such that it can follow the star’s rotation, enabling it to observe one specific area for much longer than is currently possible.

That kind of proximity doesn’t come without consequences to design and cost. SOLO will dwell well inside the Goldilocks’ Zone where water is a liquid, making one orbit about every 60 days. In this vicinity exposed surfaces could be roasted to a toasty 800° depending on the material . SOLO survives and thrives only by staying oriented behind a robust heat shield with slots through which cameras and other detectors peer out at a sun many times larger than seen from earth. That’s why the fully equipped spacecraft could run a whopping one-billion euros and may not be ready for launch until 2019.

Former moon-walkers address Congress last week on the future of the US space program and it wasn’t pretty. The overall gist was the US should maintain our lead in manned spaceflight, a laudable goal. But given the engineering reality, some of the specific suggestions they made could be judged misguided:

Cernan thinks that it’s not too late to reinstate the space shuttle. “You want a launch vehicle today that will service the ISS? We’ve got it sitting down there. So before we put it in a museum, let’s make use of it. It’s in the prime of its life, how could we just put it away?” he asked Congress. “Get the shuttle out of the garage down there at Kennedy [Space Center], crank up the motors and put it back in service.”

The shuttle was a prototype forced by budget concerns and too many masters to serve as a production spacecraft, and in that role it was proven dangerous. Occupants faced a one in 75 chance of death. That’s way, way too high for manned spaceflight to become routine, which was one of the primary things the shuttle was advertised and built. And it delivered those daunting odds at a premium price. If the cost of the two orbiters that were lost and the ensuing delays are factored in, the shuttle cost almost a billion dollars per flight by some estimates.

A smaller, second generation reentry space-plane intended to ferry humans only might work. But that still means things like wings and landing gear have to be paid for in precious payload from beginning to end. Ideally, our space program should run on a single axiom: what goes up stays up. As much as possible anyway. If humans have to come down the most efficient, proven safest way is in the smallest lightweight container possible.

Traditional, medium-sized rockets are going to give us the cheapest and safest transport into space in the forseeable future, reentry space-planes and lifting bodies could eventually play a role, but a great deal of work will have to be done before super sized winged reentry vehicles that serve as launch vehicle, high altitude hypersonic glider, mini space station, launch platform, space-truck, and many other roles can compete head to head as safely, cheaply, and efficiently as the 50 year-old Soyuz design our manned program currently depends on.